The Achilles of Rationalist Psychology (Studies in the History of Philosophy of Mind)

THE ACHILLES OF RATIONALIST PSYCHOLOGY

STUDIES IN THE HISTORY OF PHILOSOPHY OF MIND Volume 7

Editors Henrik Lagerlund, The University of Western Ontario, Canada Mikko Yrjönsuuri, Academy of Finland and University of Jyväskylä, Finland Board of Consulting Editors Lilli Alanen, Uppsala University, Sweden Joël Biard, University of Tours, France Michael Della Rocca, Yale University, U.S.A. Eyjólfur Emilsson, University of Oslo, Norway André Gombay, University of Toronto, Canada Patricia Kitcher, Columbia University, U.S.A. Simo Knuuttila, University of Helsinki, Finland Béatrice M. Longuenesse, New York University, U.S.A. Calvin Normore, University of California, Los Angeles, U.S.A.

Aims and Scope The aim of the series is to foster historical research into the nature of thinking and the workings of the mind. The volumes address topics of intellectual history that would nowadays fall into different disciplines like philosophy of mind, philosophical psychology, artificial intelligence, cognitive science, etc. The monographs and collections of articles in the series are historically reliable as well as congenial to the contemporary reader. They provide original insights into central contemporary problems by looking at them in historical contexts, addressing issues like consciousness, representation and intentionality, mind and body, the self and the emotions. In this way, the books open up new perspectives for research on these topics.

THE ACHILLES OF RATIONALIST PSYCHOLOGY

Edited by

THOMAS M. LENNON University of Western Ontario, London, ON, Canada and

ROBERT J. STAINTON University of Western Ontario, London, ON, Canada

Editors Thomas M. Lennon University of Western Ontario Department of Philosophy Talbot College 1151 Richmond Street London ON N6A 3K7 Canada

ISBN: 978-1-4020-6892-8

Robert J. Stainton University of Western Ontario Department of Philosophy Talbot College 1151 Richmond Street London ON N6A 3K7 Canada

e-ISBN: 978-1-4020-6893-5

Library of Congress Control Number: 2007939014 c 

2008 Springer Science+Business Media B.V. No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Printed on acid-free paper. 9 8 7 6 5 4 3 2 1 springer.com

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T.M. Lennon and R.J. Stainton

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1 Did Plato Articulate the Achilles Argument? . . . . . . . . . . . . . . . . . . . . . . 19 Karen Margrethe Nielsen 2 Aristotle on the Unity of Consciousness . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 John Thorp 3 The Neoplatonic Achilles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Devin Henry 4 The Unity of the Soul and Contrary Appetites in Medieval Philosophy 75 Henrik Lagerlund 5 Hume, Spinoza and the Achilles Inference . . . . . . . . . . . . . . . . . . . . . . . . . 93 Shannon Dea 6 Locke and the Achilles Argument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Jean-Pierre Schachter 7 The Reverse Achilles in Locke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Benjamin Hill 8 Cudworth and Bayle: An Odd Couple? . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 Thomas M. Lennon 9 The Achilles Argument and the Nature of Matter in the Clarke Collins Correspondence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 Marleen Rozemond 10 Leibniz’s ‘Achilles’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Jean-Pierre Schachter 11 Hume’s Reply to the Achilles Argument . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Lorne Falkenstein v

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12 Kant and Mendelssohn on the Implications of the ‘I Think’ . . . . . . . . . 215 Brigitte Sassen 13 Kant on the Achilles Argument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 William Harper 14 William James and the Achilles Argument . . . . . . . . . . . . . . . . . . . . . . . . 247 Hunter Brown 15 The Binding Problem: Achilles in the 21st Century . . . . . . . . . . . . . . . . . 257 Christopher Viger, Robyn Bluhm and Sharday Mosurinjohn Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277 Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287

Contributors

Robyn Bluhm Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada Hunter Brown Department of Philosophy, 266 Epworth Avenue, King’s University College, London, ON M6A 2M3, Canada e-mail: [email protected] Shannon Dea Department of Philosophy, 200 University Avenue West, University of Waterloo, Waterloo, ON N2L 3G1, Canada e-mail: [email protected] Lorne Falkenstein Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] William Harper Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] Devin Henry Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] Benjamin Hill Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] vii

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Contributors

Henrik Lagerlund Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] Thomas M. Lennon Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] Sharday Mosurinjohn Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] Karen Margrethe Nielsen Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] Marleen Rozemond Department of Philosophy, University of Toronto, Missisauga, 3359 Missisauga Rd. N., Missisauga, ON L5L 1C6, Canada e-mail: [email protected] Brigitte Sassen Department of Philosophy, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada e-mail: [email protected] Jean-Pierre Schachter Department of Philosophy, The University of Western Ontario, 64 Sherwood Ave., London, ON N6A 2E2, Canada e-mail: [email protected] John Thorp Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected] R.J. Stainton Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected]

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Christopher Viger Department of Philosophy, Talbot College, Richmond Street, The University of Western Ontario, London, ON N6A 3K7, Canada e-mail: [email protected]

Introduction T.M. Lennon and R.J. Stainton

1 Preliminary Remarks Paradigmatically, an Achilles argument moves from an observation about the unity of thought or consciousness to the human mind or soul needing to be a simple, unified substance. Often enough, though not always, the argument moves on from there to conclude that the mind or soul is immaterial and/or that it is immortal. We say ‘paradigmatically’ both because the argument comes in a variety of versions, some of which deviate from this gloss, and because what the key terms in the inferences mean often varies. The papers in this volume all discuss variations on the Achilles, arising across the history of philosophy and into contemporary Cognitive Science. Among the philosophers discussed are Plato and Aristotle, the Neoplatonists Plotinus and Proclus, Cudworth, Descartes, Locke, Bayle, Clarke, Leibniz, Hume, Mendelssohn, Kant, Lotze and James. The papers address these historical figures’ relationship to the Achilles: What conceptual elements did they contribute to its development? Did they offer a variation on the argument, and if so what was it? If they rejected the argument, or some core element of it, what were their grounds? As for contemporary Cognitive Science, the final paper in the volume considers the relationship between the traditional Achilles within philosophy and the pressing question in Cognitive Science of whether unities of consciousnesses – both of the sorts emphasized by philosophers and the new forms discovered by today’s cognitive psychologists – really require a single ‘unifier’ to bring various mental elements into a global representation, and if so how the human brain could manage this extraordinary feat. The central focus of this Introduction is the variation found in the Achilles arguments. Before we turn to that, however, a word is in order about the origins of this volume. The papers published here result from a group effort in the Department of Philosophy at the University of Western Ontario. The Achilles Project, as it was T.M. Lennon Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7, Phone: (519) 661-2111, ext. 85751, Fax: (519) 661-3922 e-mail: [email protected]

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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soon to be called, came into existence almost as if by chance. Early discussions among two or three of us in the Department and at the affiliated Huron College revealed an already existing interest in the history of arguments based on the unity of consciousness, with a fair amount of work already done by us on the topic. Others in the Department, with a couple of natural extensions beyond it, were canvassed about interest in the topic, and one after another of us fell into place for the coverage represented here. It was as if the project was an instance of the phenomenon whose history we were studying: we appeared to be a single consciousness working on different authors from different periods in a way that paralleled the diversity of representations which, according to the Achilles argument, are brought together in a simple mind. That we came together in this way is perhaps less a product of chance than an indication of the depth and importance of the topic, as well as the wide net of issues to which it is connected. What remains surprising, however, is that so little work has been done before on the Achilles argument. Ben Lazare Mijuskovic’s pioneering work1 was the first in modern times to draw attention to the importance of the argument, but aside from the subsequent work he has done and the previous work of project members, there is little else in print.2 Given the nature of the topic, in any case, the present volume makes no claim to being the history of the Achilles in the sense of an exhaustive or complete account, which for more than practical reasons would be an impossibility. Instead, it purports to be a fuller account, with deeper analysis, of what we take to be some of the more important instances of the argument found from antiquity to the present. In this sense, the project is on-going – with possible extensions of the unity theme already identified for future investigation. Whether the Achilles Project takes up the history of relations, of representation, and other such topics, only time will tell. Meanwhile, we would like to take this opportunity to thank an anonymous referee for many useful suggestions for improvement, Shannon Dea, Katharina Paxman, and Mark Stephenson for their editorial assistance, and the Social Sciences and Humanities Council of Canada for its financial help. Thanks also to the other contributors for their many helpful suggestions. Finally, we are especially grateful to Lorne Falkenstein for very valuable comments on earlier drafts of this Introduction.

2 Variations on the Achilles This Introduction has three main sections. In the present section, we discuss the various sorts of Achilles arguments, both with respect to how much is allegedly proven, and with respect to how the key terms are to be interpreted. We turn after that to some of the most natural objections to the Achilles. Though we do note

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The Achilles of Rationalist Arguments. The Hague: Martinus Nijhoff, 1974. A rare, recent exception is Todd Ryan, in ‘Bayle’s Defense of Mind-Body Dualism,’ Aufklärung 16 (2004) pp. 191–211, esp. 201–209.

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connections to the papers that follow, the principal aim of these sections of our Introduction is to present the argument: what it says, whom it targets, and how it has been resisted. In the third and final section we will briefly survey the papers included in this book. It will be important, both for understanding our Introduction and for reading the papers in this volume, to keep firmly in mind the various lines of thought that may be fairly termed an ‘Achilles argument’. The gloss given on p. 1 needs to be further spelled out, and in several ways. We will suggest, in particular, that there are at least four Achilles-type arguments, which we label ‘Narrowest’, ‘Narrow’, ‘Broad’ and ‘Broadest’. Let’s begin with the Narrow Achilles. It runs as follows: P1: Unification of representations takes place. P2: Only a simple, unified substance can unify representations. Therefore, C1: The human soul or mind is a simple unified substance.

There can be a host of reasons given for endorsing P1. A very obvious one is the existence of compound representations, forged from representations deriving from different modalities of the mind. We get the scent of an apple through one channel, its color through another, its texture through yet another. These are then fused into a unified representation of the sensed apple. Clearly, unification happens in such a case. But if one reads ‘unification’ in P1 broadly, as one should, other points come to light. It seems undeniable, for instance, that in acts of comparison or in thoughts of relations, some kind of ‘unification’, in the very broad sense of ‘bringing together’, is required. Whatever the grounds of support for P1, the premise is part of a Narrow Achilles. Turn now to what we label the ‘Narrowest Achilles’. It is a version of the Narrow Achilles which uses a particular sub-argument to support P2. (It is because of its particular relevance in the history of the argument that we single it out for special attention, and assign it a label.) We have in mind a trilemma, introduced in part by the Neoplatonists and emphasized especially by Mendelssohn. The trilemma runs as follows. Suppose, for reductio, that what gives rise to unification is not a simple substance, but is instead divisible into parts. There are then three options: (a) one part of the mind grasps all of the parts of the resulting representation, (b) each part of the mind grasps all parts of the resulting representation, or (c) each part of the mind grasps only a part of the resulting unified representation. Option (b) is either rejected as multiplying global perceptions, or it is accepted, but is then claimed to commit one to a single unit doing the global perceiving in any case – as each part does precisely this. The same worry about conceding the conclusion attends (a). Either way, P2 is not avoided. As for (c), there are two sub-cases, depending upon whether the parts are taken to be conscious or not.3

3 It is rare for an author to consider both sub-cases of (c), that is, both the non-conscious case and the conscious case. Exceptions include Mendelssohn and Cudworth.

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If the parts are not conscious, it is argued that unified consciousness cannot emerge. This deserves some comment. Surely, one wants to say, there are ever so many cases in which a (mere) compound performs feats that no part of it can. Nor do we need to appeal to contemporary examples like computers (whose abilities patently go far beyond what any given silicon chip can manage). One need only think of musical instruments or wagons, objects familiar to all philosophers, from the Greeks onwards: the properties of these wholes are not shared by each part. Mendelssohn, for instances, stresses that a harmony can easily enough arise out of parts which are not themselves harmonies. Several philosophers address just this point: with his concept of superaddition, Locke points to this kind of emergence, and the issue is a centerpiece of the Collins/Clarke correspondence. The objection is well taken. However, as we find in a number of papers in the volume, emergence in the case of unified representations from non-conscious parts poses a special problem. To give one example, Clarke and Mendelssohn both urge that whenever a composite seemingly exhibits qualities or powers not contained in its component parts, these qualities or powers really arise in the consciousness of other intelligent beings who contemplate the composite. Insofar as we consider these to be unities at all, they are surely mind-dependent. But mental unities, e.g., the conscious experience of sugar as at the same time white, granular and sweet, cannot be those kinds of unities. That would give rise to a circle. So, they contend, mental unities must be sui generis – and hence not the kind which emerge. (Similar considerations may be found in Bayle.) A variant on this argument, which appears to be original with Lotze, focuses on a difference between (a) the composition of physical qualities, paradigmatically instanced by the composition of motions, and (b) the kind of composition one encounters in knowledge of relations. (The latter, notice, is a case of a representational ‘bringing together’.) Lotze argues that there are only two circumstances in which a quality ever emerges, such that it is something more than simply the aggregate of its causes: when the causes all act on a singularity, or when the effect is considered not as it is in itself, but as it appears to a conscious being. For reasons that would take us too far afield here, he adds that representational unification (e.g. in knowledge of relations) cannot emerge in either of these ways. Hence it cannot be a matter of emergence from non-conscious parts at all. One might complain, rightly in our view, that the arguments just given move very rapidly indeed. However, explaining the precise details of the anti-emergence arguments would require a significant detour. It is enough for the moment to recognize this: whatever view we might have on the emergence of unificatory powers from non-conscious parts, those who support P2 on the grounds of its impossibility are arguably on solid ground, at least within their larger philosophical systems. This brings us to the final option afforded by the trilemma, namely that each part is conscious and each grasps only a part. The trouble with this option is captured nicely by a quote from Kant. Kant considers, in the Critique of Pure Reason, the following claim: representations . . . distributed among different beings, never make up a whole thought . . . and it is therefore impossible that a thought should inhere in what is essentially composite. (A352)

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Kant’s illuminating comparison is with the words of a verse distributed among different persons: not being combined in one ‘place,’ the words do not manage to form a verse. One might equally think of a contemporary computer that has at least five registers. In the first is ‘Mary’, in the second ‘had’, in the third ‘a’, in the fourth ‘little’ and in the fifth ‘lamb’. If the machine is to bind these together, even in the very weak sense of comparing them, there must be something, some special register or processor, which is able to ‘read’ what is in the various part-containing registers. It won’t do, runs this line of thought, to have one processor that reads ‘Mary’, another that reads ‘had’, and so forth, and none that reads all of them – that would give us a ‘pile’ of representations, not a unity. Kant ultimately rejects this inference, labeling it a ‘paralogism’: it is, he maintains, a fallacy of deep philosophical significance. Though he himself rejects it, he here captures the very nub of the argument for the existence of a single unit that grasps the compound representation. We have made brief mention of the emergence of consciousness. Doing so can easily give rise to a confusion. So let us stress that not just any argument with an antiemergentist conclusion regarding consciousness counts as a Narrowest Achilles. To put things metaphorically, the Narrowest Achilles is characterized not by the destination, but by the path that takes one there: that is, the key characteristic of a Narrowest Achilles is how considerations about emergence get deployed, namely within the context of the trilemma. Still less does an argument become an Achilles in general simply in virtue of endorsing similar conclusions about immaterialism or immortality. Descartes, for example, arrives at such a conclusion, but not via an Achilles. Instead, an Achilles must move from some kind of reflection about representations being ‘brought together’ in some way, to a conclusion about the need of a unified thing which carries this out. So far we have introduced two Achilles arguments, which we labeled ‘Narrow’ and ‘Narrowest’. It may help the reader keep track of things if we explain the motivation for our terminology. We call the two premise version the ‘Narrow Achilles’ because it is the very core of the argument: whatever form a specific Achilles argument takes, the template of the Narrow Achilles is always present. We think of the variant which makes use of the Neoplatonic trilemma to support P2 as ‘narrower’ because, rather than building out from the conclusion of the Narrow Achilles, thereby broadening the scope of its results, it is restricted to a tightly defined means of supporting the Narrow Achilles. In contrast, we think of arguments which take C1 on p. 3 as their departure point as ‘broader’ than the core argument itself. Plotinus provides the paradigm for a Broad Achilles. (See Henry’s paper for discussion.) For the sake of simplicity, we may crudely paraphrase his version of the Achilles as: P1: Unification of representations takes place. P2: Only a simple, unified substance can unify representations. Therefore, C1: The human soul/mind is a simple, unified substance. P3: If the human soul/mind is a simple, unified substance, then it is not material. P4: If the human soul/mind is a simple, unified substance, then it is immortal. Therefore, C2: The human soul/mind is immaterial and immortal.

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The grounds for P3 should be clear enough: material substance by its very nature is divisible into parts; so, given the Narrow Achilles, the mind or soul cannot be a material substance. P4, in turn, rests on the plausible idea that if something has no parts, it cannot be destroyed or go out of existence, at least not by any natural means. (Many authors leave open the possibility that an omnipotent God could annihilate even a simple substance.) Hence, barring supernatural intervention, the soul or mind, being simple, cannot be destroyed. How exactly the Broad Achilles goes in the various historical authors, is the burden of many of the papers included here. What is important for present purposes is to recognize the distinction between a Narrow Achilles, which (paradigmatically) uses premises along the lines of P1 and P2 to establish the existence of a unit that performs the ‘bringing together’, and a Broad Achilles, which goes on from C1 to draw conclusions about the materiality and mortality of the human mind or soul. It will also be useful to keep in mind the contrast between the two kinds of Broad Achilles: inferring only immateriality (common even into the Early Modern period) and also inferring immortality (more typical of earlier variations on the Achilles). Let us finally introduce the idea of a ‘Broadest Achilles’. This is any argument that makes use of something along the lines of P1 and P2, moves to a C1-type conclusion about the unity of the unifier, and then draws some other broader conclusion, i.e., something not about immateriality nor about immortality. We may further contrast a Broadest Achilles which is strictly philosophical from one which is not. The former are those arguments which move to a properly philosophical conclusion of some kind, but not of the sort found in Plotinus. Consider some examples. Hume, not surprisingly, seems to face a serious and pressing problem in light of the Achilles. It is his view, after all, that there is no unified self – whether material or immaterial, mortal or immortal. As he famously says, when he looks into himself, he finds only a series of perceptions. This seems to deny outright that there is a unit of any sort that does the unifying. Hence whatever arguments support C1 above are equally problematic for Hume. Kant faces a related problem. Given his larger philosophical program, Kant must insist that we cannot know the nature of the ‘I.’ More than that, we cannot even know whether it truly exists ‘in itself.’ Thus he cannot accept an argument that seems to establish, as a metaphysical certainty, that the thinker – where this means ‘the thing in itself’ – must be a simple substance. Things look especially dire for Kant because his own doctrine of the transcendental unity of apperception suggests that he ought to accept the Narrow Achilles. Indeed, the Narrow Achilles seems to be very much in line with his larger views about human psychology. (See Sassen’s paper for an extended discussion of this point.) The problems posed for Hume and Kant illustrate nicely what we intend by ‘strictly philosophical versions of a Broadest Achilles’. In particular, they underline the fact that philosophers who might have little sympathy or concern for the Achilles as an argument for, say, immortality, may yet find themselves forced to examine and respond to its key elements. This is a pattern seen repeatedly in the early modern period and afterward.

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An example of a not-strictly-philosophical Broadest Achilles would be Jerry Fodor’s arguments, at the end of Modularity of Mind, for a non-modular Central System within human cognitive architecture – without which, he contends, global and holistic integration of information of various modalities would not be possible. Fodor is making an (admittedly abstract) empirical proposal here; but, despite the empirical nature of his conclusion, his point of departure is deeply reminiscent of the Narrow Achilles. (See the final paper in this volume for further examples.) In sum, we have four kinds of arguments, each of which may with good reason be termed ‘an Achilles’: i) A Narrow Achilles: P1 (some sort of unification of representations) + P2 (simple unified substance required to unify) → C1 (the soul or mind is a simple unified substance) ii) A Narrowest Achilles: A version of the Narrow Achilles such that an appeal to the neo-Platonic trilemma is deployed to support P2 iii) A Broad Achilles: A Narrow (including a Narrowest) Achilles + P3 and/or P4 → C2 (immateriality and/or immortality of the soul or mind) iv) A Broadest Achilles: A Narrow Achilles used to reach some conclusion, strictly philosophical or otherwise, not pertaining to the immateriality or immortality of the soul or mind. (Recalling the grounds of our terminology: Arguments which take off from the conclusion of the Narrow Achilles we think of as ‘broader’ – they grant the core argument, and move forward. Arguments which instead provide support for one of the core argument’s premises, we conceive of as ‘Narrower’. The specific variant that deploys the Neoplatonist trilemma we call ‘Narrowest’.) One more refinement in terms of variations on the Achilles. We have introduced four Achilles templates. We call them ‘templates’ not because they contain explicit schematic variables to be filled in by constants, but rather because one can use these arguments to arrive at rather different lines of thought by interpreting their key terms in various more specific ways. Recalling P1, we would highlight in particular ten kinds of things which may be ‘brought together’: a) Unification of intellective representations b) Unification of various sensory perceptions, including sensory inputs from distinct modalities c) Unification of intellective representations with sensory ones d) Unification of aspects of one object into a representation of the entire object e) Unification of representations of various objects into a comparative representation of them f) Unification of representations across time g) Unification of each of the above, into a global representation of ‘the world’ (or at least of the present scene)

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h) Unification of thought-parts to form a complete judgment (i.e., joining concepts into thoughts) i) Unification of the elements of some cognitive act (as opposed to the elements in the object of that act) j) Unification of the premises in an argument so as to draw an inference Clearly, one could run an instance of the Narrow Achilles – and hence instances of the Broad and Broadest Achilles – using any of (a)–(j). Each of these ‘things brought together’ could be held to require a single cohesive unifier – though to be sure the cogency of the resulting argument might differ. (Nor are these the only kinds of items unified, in the broadest possible sense: as the papers that follow make clear, appeals to ‘ontic unities,’ as opposed to ‘representational unities,’ may be found in Condillac, James, Malebranche, and Spinoza. We revisit the issue of ontic unity at the end of Section 3.) Equally, one might have in mind any of the following three senses of ‘bringing together’. That is, rather than various relata as above, there are various relationships (or something like that), each meriting the label ‘unity’, that an author might have in mind: k) Representations brought together into a cohesive whole l) Self awareness m) Being aware of various representations even without synthesizing them into a coherent whole Thus when Plotinus speaks of unities created by the soul, he seems (following Plato) to have in mind something like the production of a compound, cohesive representation, whether formed on the basis of the various senses, on the basis of the intellect, or both. This is (k). In contrast, as Henry explains in his contribution, Proclus appealed to a very different kind of unity to defend the soul’s simplicity: the unity of an entity that is able to be aware of itself (see also Clarke on ‘the reflex act’). Finally, turning to (m), in a very novel twist Lotze points out the need for a unified self that is appeared to, even if we appear to ourselves as non-unified! Arguably even this most minimal sense of ‘bringing together’ supports C1.

3 Objections to the Achilles No introduction to the Achilles argument would be complete without some discussion of the most natural objections raised to it: the grounds on which any argument is commonly rejected elucidate the argument itself; moreover, having a sense of the salient objections to the Achilles clarifies how the authors discussed here fit into the larger picture. To give just one example, though Spinoza seems not to have addressed the Achilles directly, some of his ideas about ontic unity seem to buttress an objection to the Achilles. Grasping Spinoza’s relation to the Achilles thus

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requires familiarity with the kind of objection to which his metaphysics might make a contribution. (See Dea’s contribution for discussion.) On the other hand, such a discussion of objections cannot help but be limited in scope – not least because, at least sometimes, which objections arise depends on which specific Achilles is on offer: e.g., a response to a Broad Achilles in favor of immortality might offer reasons for rejecting P4, whereas these might not affect either the Narrow Achilles or other ‘broader’ Achilles arguments. In light of this, our aim here is certainly not to canvass every objection that has been, or could reasonably be raised. Instead, we have singled out a few that strike us as of special importance. Different historical figures have offered their own variations on some of the objections considered here; we don’t rehearse those either, leaving that to the individual papers that follow. The first objection we consider concerns P2, namely that only a simple unified substance can unify representations. Consider this modal claim. It may be read with wide-scope ‘necessary’, as in P2’, or with narrow-scope ‘necessary’, as in P2”: P2’: It is necessary that the thing which performs unification be a unified simple substance. P2”: The thing which performs unification is necessarily a unified simple substance.

Now, P2’ is arguably supported by considerations about how unification actually takes place: it does seem necessary, at least at first glance, that there be a single ‘place’ at which the various sub-representations come together. In contrast, P2” does not seem to be similarly supported, not even prima facie: Why should the actual unifier be necessarily simple and unified in this way? That is, it may be that the mind needs to contain something which is in fact a unity; but there’s little reason to believe that it contains something which is necessarily (and hence permanently) a unity. A contingently simple item would seem adequate. Given this, continues the objection, consider which of P2’ and P2” can support, say, immortality. Maybe P2” can, but P2’ pretty clearly cannot: something which merely is unified might well cease to be such, and hence might cease to be. The objection can be made more precise by putting it specifically in terms of the Aristotelian contrast between undivided and indivisible – a distinction which is worth flagging here in any case, given its recurring role in historical Achilles arguments. Suppose we understand ‘simple unity’, as several of the figures discussed in this volume clearly do, as meaning ‘lacking divisions (or parts)’. Now, the ability to unify representations seems, at least prima facie, to require a unifier which in fact is not divided into parts – for otherwise, as per the Neoplatonic trilemma, the whole could not do its job. But, even granting this, does this same integrative ability demand something which is in principle indivisible? It seems not. And, continues the objection, there is no reason to think that something which is merely contingently undivided should be indestructible: only the indivisible may reasonably be held to be immortal. A powerful reply to this objection, raised for example by Clarke, runs as follows. First, the respondent will insist that ‘unified simple substance’ be understood in the just-introduced terms, as requiring something without parts. Not just any unity will do. Second, continues the reply, when it comes to unifying representations and the like, there can be no great difference between parts which are, say,

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a millimeter apart (hence divided) and parts which have been attached by glue or some other sticky substance (hence undivided, though divisible). If there is a mystery about how the former parts could yield unity of consciousness, or comparison of representations, it is surely equally a mystery how those parts plus some kind of material fastener could do so. Thus the allegedly important contrast between undivided/indivisible turns out to be a red herring in the present context. (What’s more, whereas there are some senses of ‘unified simple substance’ on which the contrast in P2’ and P2” makes reasonable sense, it is hard to see how something could be only contingently and temporarily without parts. If an entity satisfies the demand for lacking parts, then surely it is ipso facto necessarily without parts as well. So, here again, the distinction in ‘readings’ turns out, in this context, to be without force.) The previous objection built on an Aristotelian contrast. The next objection is directed at Aristotelians who also wish to endorse the Achilles, or even just its core conclusion, that the human soul is a simple unified substance. (This argument may be found in Locke and is at the core of Hume’s attempt to respond to the Achilles in the Treatise.) Suppose, with Aristotle and the Scholastics, that sensory perception is a matter of the soul ‘taking on’ sensible forms. Now, we humans can perceive conflicting qualities at the same time: e.g., red and white on distinct balls. If the soul really is just one unit, however, without any parts, then these conflicting qualities would inhere in one and the same single thing during perception. And that is impossible. We have here something like a ‘reverse Achilles.’ One begins with a simple observation about human cognition, namely the perception of diverse and conflicting qualities at the same time. One then infers something about the thing which performs the cognitive act – this time, that it cannot be an undivided simple. Put in a nutshell, the reverse Achilles might be phrased as follows: If there is a problem about how a non-unity can grasp a compound representation, there must equally be a problem about how a unity can grasp a disparate series of representations that do not form a compound. (See the contributions by Hill and Schachter for discussion.) A usual response to this sort of objection, found in Aquinas for example, is to compare the simple soul to the center of a circle: it is the meeting point of seemingly conflicting lines. This, goes the response, is how unification takes place, consistent with the Aristotelian hylomorphic theory of perception. (See Thorp’s paper for discussion.) It’s natural to worry, however, that this doesn’t really help. If we take the analogy seriously, it doesn’t seem to be a good model of what occurs. Worse, it isn’t really a hylomorphic model anyway: it breaks down the allegedly illuminating parallel between perception on the one hand and what the Aristotelian postulates in material versions of form-inherence on the other. Surely the latter isn’t at all comparable to lines meeting at a point. On the other hand, if we don’t take the analogy perfectly seriously, then we are merely camouflaging the mystery by appeal to an image that ultimately does little work. (The same may be said, by the way, of appeals to intentionality to deal with conflicting properties being grasped by a single substance. They either do away with the parallel with material inherence or they merely re-label the problem.)

Introduction

11

So far we have seen two relatively obvious objections to the Achilles. The third objection comes from Kant, who gave the Achilles its name. Kant insists that it is a dialectical inference, a paralogism. Put in terms of our reconstruction, he appears to urge, first, that P2 (or something along those lines) is not analytic.4 That only a simple unified substance can unify representations is not knowable from concepts. Nor, Kant suggests, can this claim of necessity come from experience. Thus the argument, despite its initial attractiveness, must fail, since it cannot be defended on either of the only two possible grounds which Kant admits. Kant tries to resist the argument’s force by suggesting that ‘I think,’ which he takes to be the hallmark of representational integration, is merely a ‘logical proposition’ and hence one that carries no metaphysical implications with respect to the alleged subject of thinking. Whether his objection to the argument holds up depends, we think, upon the coherence and plausibility of this gambit. (See Harper’s paper for discussion. Speaking of Kant, it is interesting to speculate why he choose the name ‘Achilles’ for this argument. One thought is that the argument appears to have real strength, but upon close examination it turns out to have a fatal flaw, just as the mythic Achilles himself did. Another is that Kant took the name from Bayle, who characterized an Achilles argument as the champion argument characteristic of a sect. On this view, an Achilles argument was so-called in the Schools, not in reference to the invincibility of Achilles, but because of the insolubility of Zeno’s puzzle about motion. Then again, it may be neither of these.) The final objection we will discuss here rejects a core presupposition of the Narrow Achilles. P1 says that unification takes place. But maybe that is an illusion. How so? Because, goes this final objection, unity exists ‘out there.’ It is the default state of affairs, if you will. Thus there is no need for unification to occur, so as to create unity. In which case, the Narrow Achilles is blocked because there is now no need for a unifier – simple or otherwise. There are two variants on the objection. The first appeals to the common sense idea that there are multiple objects in our world, and that each of them comes already bundled with its properties. On this variant, there are many ontic unities. For example, consider an apple, whose properties of redness, crispness, crunchiness, etc., are already bound together ‘out there’; in addition, consider a skunk, whose properties of blackness, furriness and stink are bound together too. Given that the apple and its various properties are already united, goes the objection, there is no need for unification. The second variant is monistic. On this view, there is only one object to be perceived, maybe the Cartesian’s res extensa or Spinoza’s single pantheistic substance.

4 As is often the case with Kant, it is hard to know for sure how he himself intends the argument. One interpretive doubt is especially worth flagging. Despite our brief discussion on pp. 5–6, it is not entirely clear to us whether Kant takes the Narrow Achilles to be the paralogism (so that he is objecting to inferring the very existence of a unified unifier), or whether he is more concerned to resist the immortality of a simple substance, such that the paralogism would instead be a Broad Achilles.

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The historical interest of this objection lies in two places. First, something along these lines seems to be found in Spinoza, and in certain writings by William James. (See Brown and Dea for related discussion.) Second, a commitment to ontic unity might explain the otherwise very curious fact that no Achilles is to be found among the Cartesians: not in Descartes himself, nor in Malebranche, LaForge or Régis. This omission is especially glaring given that the Cartesians are in so many other respects Platonists or Neoplatonists, who moreover share the conclusions of the Broad Achilles.

4 Survey of Contributions Chapter 1 Moses Mendelssohn’s Phaedon revamped an argument for the simplicity and immortality of the soul that debuted in Plotinus’s Enneads IV, 7.6, and drew fire from Kant in the Second Paralogism in the First Critique. But did the argument really originate with Plato in the Phaedo, rather than with Plotinus, as Ben Mijuskovic has argued? In this paper Nielsen reexamines the relevant passages in the Phaedo (in particular the so-called affinity-argument for the immortality of the soul) and argues that Mijuskovic and the analyses he considers overlook a passage with a more obvious connection to Plotinus’s simplicity argument, the so-called Wooden-Horse passage in Theaetetus 184–187. Although the Wooden-Horse passage presents what Myles Burnyeat has dubbed ‘the first unambiguous statement in the history of philosophy of the difficult but undoubtedly important idea of the unity of consciousness,’ there does not seem to be sufficient evidence to conclude that Plato connected the unity of consciousness to the simplicity or indivisibility of the soul, although he insists on the unity – oneness – of the perceiving subject. Thus, it is debatable whether Plato should be honored (or reviled) as the progenitor of the Achilles argument. Although Plato clearly bases his affinity argument for the immortality of the soul on considerations of the soul’s simplicity, he does not base his endorsement of the soul’s simplicity on considerations about the unity of consciousness. Unlike Plotinus and Mendelssohn, Plato (in the Republic, at least) seems untroubled by the idea that a partite soul could be the subject of a unified consciousness. This may be due (a) to a failure to spot a putative philosophical problem or (b) to an unarticulated conviction that the reasons underlying the Achilles argument are weak, or (c) to an understanding of partition that differs from the one presupposed by Plotinus and Mendelssohn. Chapter 2 Aristotle does not accept the Achilles argument; indeed he might almost be said to repudiate it, for he accepts its premise and denies its conclusion: he agrees that consciousness is unified, but he denies that it follows that the knower is simple, incomposite, partless. Indeed, very explicitly and puzzlingly, he proposes that we must understand the knower as both one and many, single in one sense and multiple in another, a unit but not an atom, undivided but divisible. The language he uses to present this theory is somewhat mysterious: he speaks of the knower as one in number and place, but multiple in ‘being’ or in ‘account’

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(logos). He offers the analogy of the mathematical point – a point in a line, say – which is one in number and place, but can be taken either as the last point in a segment or the first in another segment. This paper presents Aristotle’s ruminations on this matter as they are developed in three different (and very difficult) texts: de Anima III, 2 & 7, and de Sensu 7. It tries to develop a sympathetic understanding of what it is that Aristotle has in mind, and to lay bare the underlying hypotheses of his work in psychology that give rise to this theory. In the end it finds Aristotle’s idea to be much less mysterious than at first it seemed. However that may be, it is clear that Aristotle’s subtle views about the unity-and-plurality of the knowing subject disqualify him for membership in the Achilles club. Chapter 3 Although the Achilles argument has its roots in Plato and Aristotle, it is (almost) fully articulated for the first time in Neoplatonism. The Neoplatonic Achilles consists of two main parts: the basic argument for immortality, plus a series of further arguments designed to show that the soul is both incorporeal and separable from body (its main premise). While all Neoplatonists seem to agree on the basic immortality argument, they employed different arguments for securing this premise, giving rise to two main versions of the Achilles: a Plotinean version and a Proclean version. The major difference concerns the incorporeality of the soul. Plotinus moves from the unity of consciousness, to the incorporeality of the soul, to its immortality, whereas Proclus moves from the capacity of the soul to reflect on itself, to its incorporeality, to its immortality. Both versions are deployed by other Neoplatonists. For example, Porphyry, Simplicius, and Philoponus all use the argument from self-consciousness to establish the separability of the soul, while Philoponus also makes use of Plotinus’ unity argument to establish its incorporeality. Chapter 4 Lagerlund traces the Achilles argument, or the argument for the unity (simplicity) and immortality of the human soul, in the works of a few medieval thinkers starting with Augustine and ending with John Buridan in the fourteenth century. It becomes apparent that the argument is foremost used by thinkers that emphasize an Augustinian or Neoplatonic conception of the soul, such as Avicenna, Peter John Olivi, Henry of Ghent, John Duns Scotus and William Ockham. He contrasts these thinkers with so-called Aristotelian thinkers such as Thomas Aquinas and John Buridan, who primarily use other Aristotelian arguments for the soul’s immortality. He further contends that the arguments for the unity or simplicity of the soul are often associated with observations of contrary appetites and inner conflicts in the soul, hence creating a paradox. Finding solutions to this paradox, he suggests, becomes a central task in later medieval philosophy and informs discussion of the nature of the human soul. Chapter 5 Despite the pervasiveness of the Achilles inference in the history of philosophy, there are a number of major figures who never make recourse to it. Among these are Hume and Spinoza, who nonetheless figure large in the history of the argument – Hume due to his lengthy criticism of it in Treatise 1.4.5, and Spinoza because Hume invokes him throughout much of that criticism. Hume argues that the Achilles argument is so similar to Spinoza’s arguments for the simple unity of substance that proponents of the former inevitably open the door to Spinozism. This

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essay considers the analogy that Hume draws between the Achilles inference and Spinozism. While ultimately no analogy holds between the Achilles and Spinozism, Dea argues that there is in fact a strong analogy between Spinoza’s and Hume’s reasons for eschewing the Achilles. However, they also encounter analogous difficulties as a consequence of their respective positions. She concludes by sketching these. Chapter 6 Locke rejects the Achilles inference explicitly on four grounds, (1) the existence of an unextended substance is humanly inconceivable, (2) an unextended and immaterial substance is as incompatible with the data of consciousness as is extended substance, (3) withal, material substance could be made to think through God’s unknowable powers, and (4) whether we are immaterial substances that persist after death is irrelevant in any case to the really important question that prompts that discussion, namely that of personal immortality. Yet, despite his complete rejection of the argument for demonstrating the immateriality of the human soul, he applies the argument, possibly derived from John Smith (1618–1652), a Cambridge Platonist, to demonstrating the necessary immateriality of the divine mind. In this paper, Schachter explores Locke’s rejection of the proof for one purpose and his application of it to the other, as well as two serious obstacles he does not address. Chapter 7 Hill challenges Schachter’s claim that, for Locke, modest agnosticism is the only rational position we can take regarding the nature of the soul. On Hill’s view, the internal logic of Locke’s criticism of the Achilles ought to have obliged him to accept some version of non-reductive, emergentist materialism. Although Locke did not, strictly speaking, formulate a version of the Reverse Achilles, he did provide arguments pointing directly toward it. This was especially the case in his Examination of Malebranche. There he thoroughly criticized the possibility of God’s absolutely simple intellect containing the diversity of idea types, as Malebranche’s thesis of seeing all things in God seemed to him to require. Locke also presented a limited version of the Reverse Achilles, an argument that sense perception is impossible if it terminates in a single point and so requires terminating in something extended. Thus, despite remaining officially committed to dualism, Hill argues that Locke is with good reason credited with laying the conceptual foundation for eighteenth-century materialism, especially French versions, and the philosophes’ use of the Reverse Achilles. Chapter 8 Ralph Cudworth and Pierre Bayle seem to differ rather dramatically in philosophical style and outlook. But the Achilles argument is deployed by both, and in ways that invite their treatment together. A look at Cudworth in Lennon’s paper leads to Bayle’s use of two very different arguments, one a latter-day version of Plotinus’s argument that the perception of a complex object requires simplicity on the side of the perceiver. The other argument is a Proclean argument on the basis of introspection, the appreciation of which requires a look at Bayle’s view of the debate between Malebranche and Arnauld over the nature of ideas. Although neither Cudworth nor Bayle comes to terms with it, the issue in both arguments is intentionality – how it is that the mind can be directed toward an object: something else in the one case, and itself, perhaps one’s self as such, in the other. Chapter 9 A discussion of the Achilles Argument prominent in the 18th century was a correspondence (1706–1708) between Samuel Clarke and Anthony Collins.

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Reading the correspondence prompted Leibniz to engage in extended exchange with Clarke. The correspondence is noteworthy for its in-depth discussion of the question whether one can show that the soul is immaterial. Clarke offered the Achilles Argument, Collins rejected it. The discussion of the Achilles argument itself is short, but the correspondence is revealing about the metaphysical presuppositions of the argument. Collins rejected the argument mainly on the ground that it failed to address the possibility that thinking emerges from material qualities. But they both rejected the idea of a conscious material subject being a collection of conscious particles. In this paper, Rozemond focuses on that aspect of their discussion. It is tempting to focus on the nature of thought in analyzing this argument, but views about the nature of matter are crucial to usage of the Achilles Argument throughout its long history. The argument purported to show that the subject of thought cannot be material because matter is infinitely divisible, and a thinking subject must be simple. Rozemond examines the various possibilities Clarke and Collins discuss for a suitably unitary material subject of thought. Chapter 10 Given the argument’s prevalence, as well as textual evidence that Leibniz was well familiar with it, it is a puzzling fact that he does not anywhere explicitly make use of it. In this paper, Schachter addresses the question of the role of the Achilles in Leibniz’s thought. As a preliminary, he examines the argument type and sets its defining conditions. He considers one of Leibniz’ very early arguments as a potential Achilles, and ultimately rejects it as genuinely such. He then focuses on Section 2 of the Monadology, in which Leibniz makes the cryptic claim that there must be ‘simples,’ since there are ‘composites.’ This is a foundational Leibnizian thesis that can be discovered in his earliest writings, but one which he never seems to defend directly. The reason, argues Schacther, is that in his mind, everything he writes is a defense of this fundamental position. In effect, it is argued that the reason the Achilles argument does not explicitly surface within Leibniz’s philosophy is that his philosophy is as a whole nothing other than an extension and elaboration of this most fundamental thesis. In briefest terms, this thesis follows, for Leibniz, from the even more basic presumption that strictly speaking only simple substances can be said to exist. From which it follows that if anything at all exists, this entails the existence of the only things that can exist, namely simple substances. He calls these simples ‘Monads,’ and Schachter argues (a) that the ‘composites’ he speaks of are our unified experiences, and (b) that he seeks to demonstrate the existence of his Monadic substances directly from the existence of our unified experiential manifolds. But this is, on the one hand, the burden of his whole philosophy and, on the other, an argument of the Achilles type. Chapter 11 Hume discusses a ‘remarkable’ argument for the immateriality of the soul – the soul must be immaterial because whatever is material is always divisible into further parts. But were multiple pieces of information distributed to separate individuals for processing, there would be no one individual who knows all the pieces of information and so no possibility of generating the awareness of wholes that phenomenal consciousness reveals us to have. Hume put an odd spin on this argument by treating it as resting on the assertion that perceptions cannot be ‘locally conjoined’ with matter because they do not occupy space. He then refuted the

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argument by claiming that, while some perceptions do not occupy space, others do. The same reasons that lead immaterialists to assert that an unextended perception could not be locally conjoined with an extended mind put materialists in a position to charge that an extended perception could not be locally conjoined with an unextended mind. Either way there is a problem, given that there are perceptions of both sorts, and the only solution is to dismiss the entire question of the substance of the soul as unintelligible. But Hume’s predecessors did not argue for the immateriality of the soul by claiming that thoughts are unextended or that thoughts must occupy the same point in space that minds do. They instead argued that thoughts contain a variety of different items of information and that the subject (or the part of the subject) that apprehends one piece of this information must be identical to the subject (or part) that apprehends the other. So, argues Falkenstein, Hume appears to have missed the point. The point is that a compound or complex impression must be apprehended by a simple subject, not that an unextended perception can only be ‘locally conjoined’ with an aspatial subject. And Hume appears to have offered a merely rhetorical answer to the real problem. Rather than explain how there can be any such thing as a compound or complex impression if there is no material or immaterial subject who apprehends all of its component parts, Hume flippantly declared that the problem is as much of a problem if one takes the subject to be immaterial as if one takes the subject to be material. Falkenstein thinks Hume was right about this, if one is looking for perceptions to be ‘locally conjoined’ with a subject. But he is not right if one understands the relation between subjects and impressions differently. All of that notwithstanding, Falkenstein argues that there is more to Hume’s argument in Treatise 1.4.5 than the brief critical survey just presented would suggest. He urges that the text goes some way to dismiss any account of the nature of the relation between perceptions and minds other than the ‘local conjunction’ account. And he argues that Hume’s rejection of the notion of a substantial soul did not impede his ability to account for compound and complex perceptions. Chapter 12 This is a paper on Kant and Mendelssohn, in particular, on the treatment each offered of the implications of the Cartesian ‘I think’. Mendelssohn’s discussion appeared in his 1767 Phaedon, Kant’s in the two editions of the Critique of Pure Reason (1781, 1787). The relationship between these texts and their arguments is quite complex. On the one hand, Kant was critical of Mendelssohn, as is evident from the ‘Refutation of Mendelssohn’s Proof for the Permanence of the Soul’ that was appended to the second edition Paralogism (B413–18). Although Mendelssohn was not named in the first edition, Kant was there similarly critical of the sort of argument that appeared in the Second Dialogue of the Phaedon, which he identified as ‘the Achilles of all dialectical inferences of the pure doctrine of the soul’ (A351). Yet, in the B-edition Transcendental Deduction of the Categories, Kant defended at least a portion of the argument we find in the Second Dialogue of the Phaedon. Given the complex interrelationship just sketched, Sassen proceeds as follows. Beginning with the arguments for the incorruptibility of the soul, she treats Mendelssohn’s argument in the First Dialogue of the Phaedon and Kant’s Refutation of it in the second edition of the Critique. Here it quickly becomes evident that Kant

Introduction

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misinterpreted Mendelssohn’s argument since the latter offered an answer to Kant’s later objection which Kant seems to have failed to notice or appreciate. Granted, the incorruptibility of the soul is not identical with its simplicity and immortality, but it has often been taken as such (though not by Mendelssohn) and his reason for not equating those concepts is itself interesting. Secondly, she turns to Mendelssohn’s refutation of materialism in the Second Dialogue of the Phaedon, in order to show how a portion of the argument is echoed in the Transcendental Deduction of the Categories, but also quite severely criticized in the A-edition Paralogism. To indicate how the debate continues into the 19th century, she ends with Johann Gottlieb Fichte’s critique of Kant. Chapter 13 In the first edition of his Critique of Pure Reason Kant characterizes the Achilles inference as the second paralogism of transcendental psychology. According to him, this famous inference to the simplicity of the soul from the requirement that representations must be combined in a single consciousness to make up a whole thought is unsound even though it is deceptively attractive. His grounds for regarding it as unsound are informed by his closely related treatment of a parallel argument to the substantiality of the soul as the first paralogism of transcendental psychology. Kant’s treatment of these arguments as unsound is closely tied to his empirical realism and corresponding rejection of the Cartesian ideal of empirical knowledge as incorrigible access to merely subjective contents of consciousness. In the second edition Kant completely rewrote his treatment of such arguments, but remained committed to counting them as unsound and to his closely related rejection of the Cartesian inspired new way of ideas. Chapter 14 In his response to the Achilles argument William James agrees that some sort of medium or vehicle is required in order to account for the unity of experience and that ‘soul’ may be used as the name of that medium. The inference by the Achilles argument to an immaterial, simple soul, however, is rejected by James for going well beyond what is warranted by experience in a number of respects. In the end, then, for James, while the unity of experience justifies an inference to some sort of ground responsible for such unity, the concept of soul can be used to represent such a ground only as a placeholder, the metaphysical characteristics of which remain as yet unknown. Chapter 15 The problem posed by the Achilles is reflected in contemporary science, where it is known as ‘the binding problem.’ This chapter reviews empirical investigation into the binding problem in psychology and in neuroscience and discusses the similarities and differences between contemporary views of the binding problem and the Achilles. In some respects, the binding problem is fundamentally different from the historical approach to the unity of consciousness; the ‘self’ being unified is assumed to be material and the answer to the question of how unity arises is sought in terms of psychological or neural structures and mechanisms. Further, while the Achilles is generally outlined in terms of complete thoughts (such as Kant’s example of the words of a line of verse), research on the binding problem focuses mainly on the unity of visual experience and assumes (either explicitly or implicitly) that other types of binding will be performed using mechanisms similar to those that unify visual experience. In other respects, however, approaches to the

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binding problem clearly reflect the responses that have been given to the Achilles. In the case of neuroscience, for example, there are two main candidate theories proposed to explain the unity of visual experience. The hierarchical model holds that the various streams of processing all converge on a ‘cardinal cell’ that represents the entire visual experience. The alternative denies that such convergence occurs and argues that unity is achieved through temporal co-activation of a group of cells, each of which represents part of the visual experience. The debate over which of these alternatives is more plausible echoes the problems raised in the philosophical literature on the Achilles.

Chapter 1

Did Plato Articulate the Achilles Argument? Karen Margrethe Nielsen

Moses Mendelssohn’s Phaedon, oder über die Unsterblichkeit der Seele in Drey Gesprächen (1767), a dialogue that owes its name, if not its content, to Plato’s eponymous work,1 presents a surprisingly resilient argument for the simplicity and immortality of the soul. The argument proceeds from the assumption that extended substance (matter) is infinitely divisible into progressively smaller parts. Halfway through the ‘Zweytes Gespräch,’ Mendelssohn’s ‘Sokrates’2 presents a thesis for refutation, a thesis that is not explicitly targeted for refutation in Plato’s dialogue, but which strongly resembles a thesis that Leibniz attacks in the Monadology. The thesis is the following: (M): ‘The ability to think may belong to an extended soul.’ Lorne Falkenstein has summarized the ensuing argument as a reductio ad absurdum of three purportedly exhaustive alternatives for explaining how an extended soul could be the subject of a unified – whole – thought.3 A thought is a complex representation, consisting of many parts, but in order to be one thought these separate parts must somehow be brought together in one mind. A mind aware of each word in the first line of Goethe’s ‘Wandrers Nachtlied,’ ‘Über allen Gipfeln ist Ruh,’ is

K.M. Nielsen Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 85746, Fax: (519) 661-3922 e-mail: [email protected] 1 Moses Mendelssohn, Schriften zur Philosophie und Ästhetik: Bearbeitet von Fritz Bamberger und Leo Strauss (Stuttgart: Friedrich Frommann Verlag, 1972). The page extensions refer to this edition. Throughout this paper, I rely on the interpretation of the Phaedon defended by Lorne Falkenstein, ‘A Double Edged Sword? Kant’s Refutation of Mendelssohn’s Proof of the Immortality of the Soul and Its Implications for His Theory of Matter,’ Studies in History and Philosophy of Science (1998), pp. 561–588. Four editions of Mendelssohn’s Phaedon appeared between 1767 and 1770, and the book was translated into several languages. Mendelssohn arranged to have a copy of the first edition sent to Kant. See Falkenstein, note 37. 2 I will refer to Mendelssohn’s Socrates as ‘Sokrates’, with a ‘k’. Although Plato’s Socrates was also Socrates with a ‘k’ (kappa), I will refrain from referring to him in Greek. 3 Lorne Falkenstein, ‘A Double Edged Sword?’, pp. 566–567 and his contribution to this volume.

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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not necessarily aware of the whole thought expressed therein.4 The mind may only be aware of each word successively, so that the hilltops are forgotten by the time the mind thinks of the calm, or the mind may be aware of each word simultaneously, but not be aware of them in relation to each other. Now, if as stipulated in (M) an extended soul were to have a thought, we may ask with Sokrates in which part of the extended soul the thought inheres. (i) If the part is itself made up of parts, we must determine in what part of the part of the soul the thought inheres, thus embarking on a quest for the ultimate part in an infinite series. If, on the other hand, the part is simple, we reject the assumption that the soul is extended and give up the argument (Mendelssohn’s Sokrates is a Cartesian about matter, it seems) (Phaedon, pp. 96–98). (ii) If, on the other hand, we say that each part of the extended soul thinks the whole thought, we’ll replicate the same function needlessly – we’ll have as many whole thoughts as there are parts of soul: an infinite number (Phaedon, pp. 97–98). But, (iii) If each part merely thinks part of the thought, we’ll violate the principle of the unity of consciousness, since there won’t be an awareness of the whole thought (Phaedon, p. 96). Rather, there will be one awareness of the calm, one of the hilltops and so on, which is not the same as an awareness of any one thought expressed by Goethe’s line. But it’s simply a fact that we do have a unified awareness of whole thoughts. Therefore, it cannot be the case that each part thinks a part of the whole thought.5 Sokrates, Mendelssohn’s mouthpiece, concludes his trilemmatic argument for the simplicity of the soul by pointing out that the thesis (M), ‘The ability to think may belong to an extended soul,’ is self-refuting. From (M), Sokrates and his friends Simmias and Cebes (reunited with Socrates for the encore performance) are able to derive ‘den schnurstrachs entgegengesetzten Satz’ (the exact opposite proposition) by a series of supposedly valid inferences.6

4 Goethe wrote the ‘Wandrers Nachtlied’ in September of 1780, so this is obviously my illustration, not Mendelssohn’s. 5 My reconstruction of the argument follows Lorne Falkenstein, ‘A Double Edged Sword?’, pp. 566–567. The ‘words-of-a-verse’ illustration is Kant’s own (although the underlying idea is found in ovo in Plotinus’ Enneads, IV, 7, line 18–19). As Kant writes in the first edition of the Critique, presenting the third lemma of the Achilles argument, ‘For representations (for instance, the single words of a verse), distributed among different beings, never make up a whole thought (a verse), and it is therefore impossible that a thought should inhere in what is essentially composite [einem Zusammengesetzten, als einem solchen]. It is therefore possible only in a single substance [in einer Substanz], which, not being an aggregate of many, is absolutely simple [schlechterdings einfach]’ (A 352). I quote Norman Kemp Smith’s translation of Immanuel Kant’s Critique of Pure Reason (London: Macmillan Press, 1992). For the German I have consulted Immanuel Kant, Kritik der reinen Vernunft (Frankfurt am Main: Suhrkamp Taschenbuch Verlag, 1974). 6 Surveying the road they have traveled, Sokrates observes: ‘Wir haben voraus gesetzt, das Denkungsvermögen sey eine Eigenschaft des Zusammengesetzten, und, wie wunderbar! aus dieser Voraussetzung selbst bringen wir, durch eine Reihe von Vernuftschlüssen, den schnurstrachs entgegengesetzten Satz heraus, daÿ nehmlich das Empfinden und Denken nothwendig Eigenschaften des Einfachen und nich Zusammengesetzten seyn müÿten: ist dieses nicht ein hinlänglicher Beweis, daÿ jene Voraussetzung unmöglich, sich selbst widersprechend, und also zu verwerfen sey? – Niemand kann dieses in Zweifel ziehen’ (Phaedon, p. 98).

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Because it is a brute fact that we are capable of thinking whole thoughts, and likewise a fact that this would be impossible on the assumption that the soul were extended and material, the thinking soul cannot be extended and material. Rather, the soul must be unextended (not composed of parts) and immaterial (simple). The refutation of (M) provides a belated defense of a premise that Mendelssohn took for granted in his proof for the immortality of the soul in the first part of the Phaedon (pp. 72–73), namely the that the soul is a simple substance. Mendelssohn’s proof bears a superficial resemblance to an argument presented by Plato’s Socrates in his attempt to calm the minds of his anxious friends while waiting for the hemlock in Plato’s Phaedo. Simmias and Cebes should not fear death, Plato’s Socrates argues, because death is the separation of soul from body, and the soul (which is the person proper) is simple and immaterial, unlike the material body. A simple substance cannot dissolve, and is thus immortal. Mendelssohn’s Sokrates, on the other hand, argues that the soul is immortal by noting that a simple substance could only cease to exist either (A) by being destroyed (annihilated) or (B) by gradually losing its power to think until it finally has no such power at all.7 The latter alternative is impossible, since such a gradual loss of power would still require a last step, a transition from being to not-being. But that’s not a gradual transition at all. And since natural destruction requires the dissolution of constituent parts, a simple substance cannot cease to exist in the same way as a composite substance. It is therefore ‘incapable of being destroyed by natural means,’ as Mendelssohn circumspectly puts it,8 leaving it open that God, in an act of complete annihilation, could place his divine finger on the simple soul-substance, not exactly squashing it like an ant (ants, after all, consist of parts), but making it vanish into nothing. (Plato’s Socrates does not bother with the threat of an all-mighty destroyer God, for reasons that should be obvious when we recall his theory of matter in the Timaeus. Matter is not the kind of thing that could be destroyed).9 Mendelssohn’s Phaedon is a curious work. For the most part, the concerns of Mendelssohn’s characters echo those of Plato’s characters in the Phaedo, although they address one another in impeccable German (‘Sage mir, mein lieber Simmias! . . .’ ‘Mein lieber Sokrates . . .’ etc). But as the trilemmatic argument for the simplicity of the soul demonstrates, Mendelssohn’s Phaedon is not without independent philosophical merit. One would be hard pressed to find anything quite like his argument for the simplicity of the soul in Plato’s Phaedo, and Mendelssohn’s argument for the immortality of the soul moves beyond any of Plato’s arguments.

7

See e.g. Phaedon, p. 81 for a summary of the preceding argument. ‘Durch natürliche Kräfte kann nichts zernichtet warden,’ p. 81. 9 In the Timaeus, Plato is thought to identify the ‘receptacle’ with primordial matter, and calls it the ‘wet nurse of all becoming’ (49a–52d). He also calls it ‘space’, and says that it ‘exists always and cannot be destroyed’ (52b). Thus, if ‘space’ and ‘receptacle’ are other names for matter prior to any en-forming activities on the part of the demiurge, primordial matter is eternal. Mary Louise Gill, ‘Matter and Flux in Plato’s Timaeus’ Phronesis (1987), pp. 34–53, defends a view according to which matter is not the receptacle, but rather a set of permanent simples that the demiurge finds in the receptacle. Either way, the demiurge is not capable of creating or destroying matter. 8

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Although the conclusion that Mendelssohn’s Sokrates seeks to draw from the alleged simplicity of the soul is the same as the conclusion Plato’s Socrates sought to draw (‘the soul is immortal’), the argument that Mendelssohn’s Sokrates uses to secure the major premise (‘the soul is a simple substance’) is of an entirely different nature. Immanuel Kant later named Mendelssohn’s argument for the simplicity of the soul the ‘Achilles of all dialectical inferences in the pure doctrine of the soul’ (A351). Although Kant warns that it is ‘no mere sophistical play,’ but rather ‘an inference which appears to withstand even the keenest scrutiny and the most scrupulously exact investigation,’ he nevertheless singles it out for refutation in the Second Paralogism in the first edition of the First Critique (1781). Kant’s reverence for, but ultimate rejection of, the Achilles argument even led him to attach a refutation of ‘Mendelssohn’s proof of the permanence of the soul’ in the second edition of the First Critique (1787), though Kant appears to have underestimated the strengths of Mendelssohn’s full position.10

1.1 Mijuskovic and the Question of Attribution Did Mendelssohn suck the Achilles argument from his own breast, or did he perhaps borrow it from contemporary or near-contemporary sources (Leibniz, for instance)? The question of the origin of Mendelssohn’s argument is worth posing, especially since it bears on our interpretation. The most likely candidate is explicitly cited by Mendelssohn, and it is a Late Hellenistic source rather than an Early Modern one: Plotinus’ Ennead IV, 7. But this raises a further question: Whether rightly or not, the Neo-Platonists are sometimes dismissed as eclectic, if not downright derivative, thinkers. If the argument is adopted from Plotinus, should we not expect to find it in Plato as well? My question, then, is whether the Achilles can be found in Plato’s Phaedo, or anywhere else in the Platonic corpus. It’s significant that Mendelssohn himself does not attribute the Achilles to Plato, but rather cites Plotinus Ennead IV, 7 as his source. The similarities between Mendelssohn’s trilemma and Plotinus’ argument in the section devoted to the immortality of the soul are indeed striking. Just like Mendelssohn, Plotinus attempts to refute the hypothesis that the soul is extended (diestôs) (and therefore divisible) by way of a tri-partite reductio. Either (i) different parts of the perceiving soul will receive different parts of the object. But if parts of soul have the ability to perceive, it’s unreasonable to deny that parts of parts have this ability, and so on ad infinitum. Thus, we won’t be able to determine in what part of the soul the perception occurs (IV, 7, 27–34). (ii) If, on the other hand, any part of the soul takes in the whole object, we’ll be left with an infinite number of perceptions of the whole object. After all, any magnitude (megethos) is infinitely

10 See Lorne Falkenstein, ‘A Double Edged Sword?’, Appendix A: The soundness of Kant’s refutation of Mendelssohn.

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divisible by nature (eis apeira diaireisthai),11 and the perceptions of the sense-object will therefore be infinite for each part (IV, 7, 34–37). But (iii) if the multitudinous perceptions we have of one object were to arrive at different termini, as they would if the soul were an extensive magnitude, we would be left with many perceptions of different things rather than one perception of one thing, ‘just as if I perceived one thing and you another’ (IV, 7, 18–19). In other words, the unity of consciousness would be lost. On the basis of these arguments, we should conclude that the soul is un-extended: the soul like a point rather than a line. Even this brief survey, which does not do justice to the details of Plotinus’ argument, reveals that Mendelssohn must have found Plotinus’ Ennead IV, 7 a rich ore to mine for simplicity-arguments, arguments which he proceeded to pour into the dramatic mold of Plato’s Phaedo. It seems, then, that Mendelssohn’s title by itself should not be taken to imply that all of his arguments originate in Plato’s Phaedo. Mendelssohn presumably realized as much – that’s why he cites Plotinus, not Plato, for the simplicity trilemma. Despite Mendelssohn’s conspicuous omission of a reference to Plato for the Achilles argument, Ben Mijuskovic nevertheless identifies Plato’s Phaedo as its first locus in his book-length study The Achilles of Rationalist Arguments (1974) and subsequently in a series of articles that followed its publication.12 Mijuskovic’s identification of Plato as the progenitor of the argument seems to reflects his adherence to A. O. Lovejoy’s approach to the history of ideas. In his 1933 William James lecture at Harvard, which appeared as The Great Chain of Being in 1964, Lovejoy argued that the task of the historian of ideas is to trace what he calls ‘unitideas’ through time. These unit-ideas remain essentially the same after Plato; later authors merely present variations on a Platonic theme. To Lovejoy’s ears, as well as to Mijuskovic’s, A. N. Whitehead’s chirp that ‘the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato’ rings literally true.13 It’s therefore unsurprising that Mijuskovic should take himself to have found the Achilles argument in Plato: it fits perfectly with his methodological outlook. Mijuskovic sets out to do for what he calls ‘the simplicity argument’ what Lovejoy did for ‘the great chain of being.’ In the introduction to The Achilles of Rationalist Arguments, Mijuskovic programmatically states that

11 It’s significant that Plotinus takes (extensive) magnitudes to be infinitely divisible, as this is a presupposition of Mendelsohn’s trilemmatic argument as well. Pretty obviously, the assumption is at work in Plotinus’ first lemma as well, but he only spells it out in connection with the second lemma. 12 Ben Lazare Mijuskovic, The Achilles of Rationalist Arguments. The Simplicity, Unity, and Identity of Thought and Soul from the Cambridge Platonists to Kant: A Study in the History of an Argument (The Hague: Martinus Nijhoff, 1974). 13 Lovejoy endorses Whitehead’s remark in the opening of chapter two of The Great Chain of Being: ‘The most fundamental of the group of ideas of which we are to review the history appears first in Plato; and nearly all that follows might therefore serve as an illustration of a celebrated remark of Professor Whitehead’s, that “the safest general characterization [etc]” ’. Arthur O. Lovejoy, The Great Chain of Being (Cambridge, Mass.: Harvard University Press, 1964), p. 24.

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K.M. Nielsen The simplicity argument, although distinguishable into a quartet of separable purposes, nevertheless essentially remains what A. O. Lovejoy designated a ‘unit-idea’. In other words, the idea itself, or more properly in this case the argument itself, remains the same. It does not change, although to be sure there are minor refinements and technical developments.

Noting that scholars have been reluctant to grant that Plato’s basis for concluding that the soul is immortal in the affinity argument is its simplicity,14 Mijuskovic nevertheless concludes that the first occurrence of the Achilles is in the Phaedo, specifically 78b–80e.15 Unfortunately, Mijuskovic is not always perfectly clear on what his ‘unit-idea’, or, better, ‘unit-argument’, is supposed to be, and it is therefore perhaps easier for him to ‘trace’ it through time than it would have been if he had distinguished clearly between the ‘hard core’ of the argument and various related arguments; arguments that may appeal to similar considerations or arrive at similar conclusions, albeit by different routes.16 In order to determine whether Plato in fact did articulate the Achilles-argument, we need a template of the argument. I believe the clearest statements are found in Mendelssohn and Kant. Their formulations should be paradigmatic, insofar as Kant named the argument the ‘Achilles’ in response to Mendelssohn. Although Kant takes the conclusion of the argument proper to be that the soul is a simple (and hence immaterial) substance (he charges that this is a paralogism), we may still look at the Achilles proper as an initial stage in a longer argument for the immortality of the soul (or its ‘permanence’, as Kant puts it in his refutation of Mendelssohn). Let me, therefore, distinguish between what I will call the ‘Broad Achilles’ argument, and the ‘Narrow Achilles’ embedded in it.17 The ‘Narrow Achilles’ is the argument from the unity of thought to the simplicity of the soul, what Kant calls the nervus probandi of the argument he criticizes in the Second Paralogism (A 352). The ‘Broad Achilles’ is the argument from the unity of thought, via its simplicity, to a conclusion stating that the soul is immortal. 14

A. E. Taylor, Plato: The Man and His Work (London: Methuen, 1949); F. M. Cornford, Plato‘s Cosmology: the Timaeus of Plato (New York: Humanities Press, 1952), commenting on Plato’s Phaedo 78d. 15 Mijuskovic: ‘I have tried to show how the argument from the alleged simplicity, unity, and identity of our thoughts and our soul was repeatedly used in the 17th and 18th centuries. I have maintained that its first appearance occurs in Plato’s Phaedo, but that it underwent significant changes at the hands of Aristotle and Plotinus’ (The Achilles of Rationalist Arguments, p. 138). Even more categorical is his statement in ‘The Simplicity Argument and the Freedom of Consciousness,’ Idealistic Studies (1978), pp. 62–74: ‘This proof [The Achilles], which ultimately derives from Plato (Phaedo 78b) has been repeatedly used and has had a major influence in shaping philosophic discussion since the Hellenistic age’ p. 62. 16 The problem is, as far as I can tell, that Mijuskovic permits that one and the same ‘argument’ may be used to defend different conclusions (see e.g. his introductory remarks to ‘The Simplicity Argument and the Freedom of Consciousness’ and The Achilles of Rationalist Arguments). Thus, any author who employs considerations about the unity of thought to prove some thesis or other is said by Mijuskovic to employ the Achilles. This reveals that Mijuskovic operates with a rather eccentric, if not outright confused, conception of the identity-conditions of arguments. 17 Cf. Lennon & Stainton’s introduction to this volume.

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1.1.1 ‘The Broad Achilles’ (1) Human awareness is a unified multiplicity. (2) A unified multiplicity (Kant’s example: the words of a verse) can only be a modification of a simple substance. (3) If a substance is divisible, then it is not simple. (4) Material substances are extended, and therefore (infinitely) divisible. (5) So, a unified multiplicity cannot be a modification of a material substance. (6) So, a unified multiplicity must be a modification of a simple, immaterial substance – the soul. (7) Simple substances cannot be destroyed. (8) So, simple substances are ‘deathless.’ (9) So, the soul is immortal. Mendelssohn’s trilemmatic argument for the simplicity of the soul supports (2). As we have seen, he adduces several additional premises to infer (8) and (9). Steps (7) though (9) give a general picture of the inference from the simplicity and immateriality of soul to its immortality. Despite Kant’s judgment that the argument is ‘no mere sophistical play’ it’s not particularly convincing either – the step from (1) to (2) was challenged by Locke, who, as Jean-Pierre Schachter has noted, argued the by parity of argument, a multiplicity, however unified, cannot be the modification of a simple substance.18 Premise four would have struck Democritus, Leucippus or any atomist as dubious. The inference from (7) to (8) is equally problematic, at least as stated. As both Mendelssohn and Kant recognized, the simple substance could be annihilated by God, or it could gradually lose its ‘intensive’ magnitude. (Mendelssohn tried to counter the latter suggestion by arguing that even this purportedly gradual way of perishing nevertheless requires an abrupt transition from being to not-being at the very end, and that this transition is impossible.) I’ll leave these objections to the side – my task is to determine whether Plato articulates the Achilles argument. A provisional answer to this question is best expressed in German: ‘Jein’ – yes and no. Elements of the argument are present in Plato’s dialogues, but we won’t find all the steps articulated as one argument. The first step, from (1) to (2), strongly resembles an argument found in the Theaetetus (184a–187b), not in the Phaedo, while steps (7–9) are found in the Phaedo (78b–80e), not in the Theaetetus. Thus, somewhat ironically, elements of the Broad Achilles seem to be distributed over two different dialogues – they are, as we might say, ‘modifications of different literary substances.’ Was Plato, then, conscious of the Achilles? In the case of the Narrow Achilles, that depends on whether he inferred that the soul is a simple substance based on considerations of concerning the unity of thought. In the case of the Broad Achilles, it depends on whether he had the Narrow Achilles and whether he related an argument for the simplicity of soul to an argument for its immortality. I will argue that in the final analysis, there is little 18

In correspondence, Schachter has mentioned John Locke, Locke’s Philosophical Works (London: George Bell & Sons, 1906), Vol. II, Sect. 39, p. 439 in this regard.

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evidence to suggest that Plato expressed either the Narrow or the Broad Achilles in the form that we find it in Mendelssohn. Thus, there is no unequivocal evidence that Plato would be a proper target for the criticism leveled at the Achilles in Kant’s Second Paralogism. If Plotinus is Mendelssohn’s source, then he, rather than Plato, is its author.

1.2 The Affinity Argument: Dying in High Wind My first task will be to show that, pace Mijuskovic, the ‘affinity argument’ (Phaedo 78b–80e) does not express the Narrow Achilles, although the simplicity of the soul figures prominently in Plato’s argument. There is a certain family resemblance to be sure, but family-resemblance is not identity. Insofar as we are tracing a ‘unitargument’ through time, what matters is whether Plato articulated an argument of the same structure, with like premises adduced in support of like conclusions. In the Phaedo, Socrates and his frightened interlocutors conceive of death as dissolution of the soul. This is what Cebes and Simmias fear will happen to Socrates when his soul leaves his body. But Socrates makes fun of their fear, saying: You seem to have this childish fear that the wind would really dissolve and scatter the soul, as it leaves the body, especially if one happens to die in high wind and not in calm weather (77e).

In other words, if the soul were a compound, we should have reason to fear dying in high wind, as the soul will be dispersed faster, and we won’t enjoy much of an afterlife. If we die in calm weather, on the other hand, we may hope to live a little longer. Cebes distances himself from the ‘childish fear’ – it’s not really he who fears this, but the child inside him. So Socrates should try to persuade the child inside the man not to fear death like a bogey. To cut a long story short, Socrates tries to put the child’s fears to rest by arguing that the soul is not the kind of thing that could be scattered. Socrates develops an argument that trades on the ‘affinity’ between soul and forms, and body and visible particulars.

1.2.1 ‘The Affinity Argument’ (1) Something is liable to be split up into its component parts only if it is composite (78c). (2) The invisible forms of F remain the same and do not tolerate any change whatever (they are divine, deathless, intelligible, uniform, indissoluble) (78d). (3) The many visible F particulars never in any way remain the same as themselves or in relation to each other (they are human, mortal, multiform, unintelligible, soluble) (78e). (4) The soul investigates by itself when it passes into the realm of the invisible forms (79d).

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(5) The soul is dragged down by the body to the things that are never the same when it investigates through the bodily senses (79c). (6) (Like is known by like). (7) The body is like the many visible F things (80b). (8) The soul is like the invisible forms of F (80b). (9) So, the soul is ‘altogether indissoluble or nearly so’ (80b).19 Socrates concludes that if the soul is pure when it leaves the body – if it has not adopted any of the body’s desires and drags nothing bodily with it – the soul will not be scattered or destroyed when it leaves the body, as the majority of men say. Instead, it will ‘make its way to the invisible, which is like itself, the divine and immortal and wise, and arriving there it can be happy, having rid itself of confusion, ignorance, fear, violent desires and the other human ills, and, as is said of the initiates, truly spend the rest of time (ton loipon chronon) with the gods’ (81a). What matters for the immortality of the soul, then, is not whether one dies in high wind or calm weather, but whether one has practiced for dying by not indulging in bodily pleasures, but rather dissociating oneself from the body. This is nothing other than practicing philosophy in the right way, or, as Socrates puts it, ‘practicing for death’ (81a). The affinity argument is not Plato’s final word on the immortality of the soul (the so-called final argument at the end of the dialogue is usually recognized as stronger). Simmias later introduces the materialist harmonia-theory of soul as an alternative to the model of the soul presupposed in the affinity-argument. Still, some crucial premises in the Broad Achilles are clearly present in the affinity argument. But we’re equally clearly missing several crucial premises. For there is no appeal to the unity of thought or consciousness. Lorne Falkenstein assesses the relation between Plato’s affinity argument and later developments of the Achilles as follows in ‘A Double Edged Sword?’: Plato tried to show the simplicity of the soul by appealing to the fact that the soul knows the forms, which are indivisible, and claiming that like must be known by like (Phaedo 78b– 80b). Later philosophers, including Mendelssohn himself, offered a modified argument that turns on the claim that the soul must be indivisible because thought is indivisible (Plotinus Ennead IV, 7 is cited by Mendelssohn as his source.)20

I think Falkenstein is right to observe that Plato’s basis for inferring the simplicity of the soul differs from that of Mendelssohn. Plato wants to argue that the soul is indivisible because it resembles the thing that it knows, the forms. He does not appeal to the unity of thought, nor to the necessity of a simple substance as its condition of possibility (Kant’s Second Paralogism). Nevertheless, we do find an argument closely related to Mendelssohn’s argument for the simplicity of the soul in the 19 The qualification is odd, but probably reflects Socrates’ conviction that those souls who associate with the body take on the body’s properties. Thus, the soul only shares the properties of forms if it has dissociated itself from the body. 20 Falkenstein, ‘A Double Edged Sword? Kant’s Refutation of Mendelssohn’s Proof of the Immortality of the Soul and Its Implications for His Theory of Matter,’ p. 566.

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Platonic corpus. But it does not appear in the Phaedo, the only dialogue Mijuskovic considers at any length. Rather, we find an argument for the unity of consciousness, and possibly even for the simplicity of soul, developed in the so-called Wooden Horse passage in the Theaetetus (184a–187b). An argument strongly reminiscent of Plato’s argument for the unity of consciousness in the Theaetetus appears as a premise in Plotinus’ Enneads IV, 7 (especially lines 8–12) – precisely the chapter that Mendelssohn cites as the source of his argument for the simplicity of the soul. So, although Plato does not articulate either the Narrow or the Broad Achilles in the Phaedo, it looks as if he articulates an argument that has close affinities to the Narrow Achilles elsewhere, and that may even have inspired Plotinus’ (and hence Mendelssohn’s) argument for the simplicity of soul. It is therefore quite surprising that both the early moderns and Mijuskovic overlook the Theaetetus entirely.21 There isn’t a single reference to the Wooden Horse passage in the extensive literature that Mijuskovic considers, nor in Mijuskovic’s study itself, which is odd, given how closely it parallels the third lemma of Mendelssohn’s argument.

1.3 Knowledge is Perception: Theaetetus 184a–187b Let me attempt to explain how the Theaetetus-passage is relevant to the Achilles. In Enneads, IV, 7 Plotinus observes that the terminus of perception must be ‘truly one’ (hen on ontôs), and therefore cannot be the many organs of sense (eyes, ears, tongue, etc). The argument is part of his effort to prove that the soul is not and cannot be an extensive magnitude (megethos): If one [object of perception] enters though the eyes, another through the sense of hearing, there must be some one place to which they both go. Otherwise, how could we state that these are different, if the objects of perception do not arrive at the same place?

Judging that the sound of a woodpecker differs from the sight of one requires the ability to hold both perceptions before the mind’s eye for comparison. But (Plotinus does not spell out his reasons fully) the ears are incapable of appreciating visual stimulus, just as the eyes are incapable of appreciating auditory stimulus. If, per hypothesis, the consciousness of sound resided in the ears, and the consciousness of color in the eyes, judgments that we in fact make about the proper objects of each sense would be impossible. But they are not. Therefore, extended organs such as eyes and ears are not the loci of perceptual awareness. Rather, the soul – to hegemonikon – is. The soul holds the perceptions together in one act of consciousness, and that requires, according to Plotinus, that the soul is ‘truly one.’ For Plotinus, only an indivisible terminus is truly one. Plotinus’ compressed argument for the conclusion that the terminus of the perceptions of diverse senses must be ‘one’ is undoubtedly inspired by Plato’s structurally similar argument in the Wooden Horse passage in the Theaeteus, some 21

There’s one possible exception: Simon Foucher refers to the Theaetetus, but not to the wooden horse passage in particular. Tom Lennon identified the reference in Foucher.

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six hundred years earlier. In his stimulating commentary to the Theaetetus, Myles Burnyeat observes that in the Wooden Horse passage, The unity of the perceiving subject is demonstrated from the unity of the thinker who surveys and judges the proper objects of different senses, for which purpose the thinker must also be a perceiver capable of exercising and coordinating a plurality of senses. Plato’s achievement in this passage is nothing less than the first unambiguous statement in the history of philosophy of the difficult but undoubtedly important idea of the unity of consciousness.22

Plotinus exploits the argument from the soul’s ability to judge different types of perceptions to show that not only must the perceiver be one, it must also be without parts, like a point on which the different perceptions converge. As far as Plotinus is concerned, the unity of thought (and the unity of consciousness) requires a simple soul. But when we turn to the Theaetetus, it becomes clear that Plato significantly remains mum on the question of the connection between the oneness of the terminus of different perceptions and the simplicity of the terminus. Judging from his silence, it’s not capricious to infer that Plato does not find the thought of a unified soul consisting of parts inherently troubling. What he does find troubling, rather, is the thought of a partitioned soul where each part is incapable of being conscious of the ‘mental states’ of the others. This is brought of in his argument in the Wooden Horse passage against Theaetetus’ suggestion that the sense organs – eyes, ears, tongue, etc – could be loci of knowledge. For none of these senses have access to the proper objects of the others, and hence they are separate parts in the strong sense that they are incapable of communicating with one another. In the Theaetetus 184a–187b, Plato presents a refutation of the thesis ‘Knowledge is perception.’ The thesis (T) is put forward towards the beginning of the dialogue by the eponymous interlocutor as an answer to Socrates’ question ‘What is knowledge?’. Theaetetus’ ‘first born’ child, (T), is, it appears, still-born. But although Theaetetus’ first proposal fails, it nevertheless puts Socrates in a position to discern its fatal flaw, which turns out to be a misconceived notion of what perception is, based on a misconceived notion of the perceiving subject. It is this misconceived notion of the perceiving subject that the Wooden Horse analogy is supposed to bear out. Before we see how, we must assess Plato’s analysis of the model of perception underlying (T) that makes the Wooden Horse analogy apt. In spite of the aporetic nature of the exchange at 184a–187b vis-à-vis the initial problem: ‘What is knowledge?’, Socrates is still able to conclude the passage on an optimistic note. He observes that the interlocutors ‘have made a little progress’: they will no longer be ‘looking for knowledge in sense-perception at all’ but rather, Socrates states, ‘in whatever we call the activity of the soul when it is busy by itself about the things which are’ (187a). The latter activity, the soul’s engagement or business (pragmateia) with beings (ta onta), itself by itself (autê kath’autên), is

22

M. F. Burnyeat, The Theaetetus of Plato, translated by M. J. Levett (Indianapolis: Hackett, 1990), Commentary, p. 58.

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immediately identified as judgment (doxazein). The upshot of the analysis is that sense-perception fails to qualify as knowledge because it does not involve the exercise of the capacity for judging sense-impressions, i.e. for judging that x is F – a capacity which presupposes (a) the application of a concept of being that cannot be attained through the senses and (b) the application of predicates that don‘t arise through sense-impressions. This is deemed sufficient to vindicate, not only the quite trivial truth that sense-perception and knowledge do not amount to the same thing – any trompe l’oeil picture could convince us of as much23 – but the far more radical thesis that no sense-perception amounts to knowledge: N: ‘No perception is knowledge.’ The tenet N is radical, but should hardly surprise anyone with the vaguest acquaintance with Plato’s thought. In the Republic books V, VI, VII and X, Plato goes to great lengths to prove that aisthêsis is not epistêmê. Rather, perception remains in the domain of eikasia and pistis, the lowest stages in the simile of the divided line. Perception’s only cognitive achievement is doxa, it cannot attain anything that comes close to epistêmê.24 However, the fact that the arguments in the Republic and in the Theaetetus 184a–187b issue in the same conclusions should not divert our attention from the fact that the premises and considerations thought to underwrite N differ radically, as John M. Cooper has persuasively argued.25 In the passage from the Republic which I have quoted, perceptions contradict each other in the manner of beliefs. A few lines further on, at 524a, Plato speaks of the sense of touch ‘reporting to the

23 I’m thinking of typical instances of sense-deception: a two-dimensional shape appearing threedimensional, for instance. 24 This is the upshot of Plato’s discussion of the ‘summoners’ in Republic VII, 523c–524e. Asking us to study three fingers on our hand, Socrates draws attention to the peculiar tendency of senseperception to ascribe opposite predicates to one and the same object simultaneously. The ringfinger, placed between the pinkie and the middle finger, appears ‘big’ relative to the former and ‘small’ relative to the latter, but the difference in length is the same in both cases. This puzzle awakens us to the problem of what ‘big’ and ‘small’ really are. They cannot be defined in terms of sensibles, since any object we’ll want to define ‘big’ with reference to, may very well turn out to be small in relation to another. (Rep. VII, 523b–c). Sensibles like ‘one inch’ cannot explain either ‘bigness’ or ‘smallness’ since the same state of affairs will account for opposite predicates equally well. Definitions must be sought elsewhere – in the realm of intelligible forms. I here follow Gail Fine in reading the ‘summoners’ passage in the light of the similar puzzle of height in the Phaedo, 102c–103a. (G. Fine, ‘Plato on Perception: A Reply to Professor Turnbull, “Becoming and Intelligibility”,’ Oxford Studies in Ancient Philosophy, Supplementary Volume (1998). Fine argues that the ‘summoners’ passage in book VII is distinct from the example of the bent stick in book X, since the latter is simply an illustration of the distorting effect of perspective. I would like to add in support of this view that the stick does not look both bent and straight simultaneously – reason alerts us to the conflict. 25 John M. Cooper, ‘Sense-Perception and Knowledge,’ Phronesis 15 (1970), pp. 123–146; reprinted in Gail Fine (ed.): Plato 1, Oxford Readings in Philosophy (Oxford: Oxford University Press, 1999), pp. 355–376. Cooper rejects the attempts of Cherniss and Cornford to read the summoners passage and the Theaetetus passage as expressing the same doctrine.

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soul (parangellei tê psuchê) that the same thing is perceived by it to be both hard and soft.’ The sense appears to be able to formulate its findings in propositional form, it ‘wires’ fully articulated messages back to headquarters – the soul. Plato describes the sense-organs’ communication with the soul in terms of ‘esêmênen’ (523d), ‘sêmainei’ (524a) and even ‘legei’ at 524a.26 These are clever sense-organs – they are capable of judging that the same X is both F and G at the same time and alert the soul to this fact. The senses do not simply provide the raw-material for the subsequent judgment, carried out by the soul; they structure impressions by employing categories like ‘hard’, ‘soft’, ‘long’ and ‘short’, ‘sameness’ and ‘difference.’ Although the senses cannot solve the puzzle of opposed predicates, they are able to formulate it. The proof for N in Theaetetus 184a–187b, in contrast, turns on a flat out denial of the contention that perception is structured in the same way as beliefs, and – a fortiori – that perception can give us true belief or even knowledge. The Theaetetus, then, marks a radical development in Plato’s thought: his earlier undifferentiated notion of sense-perception, both as a passive ‘experience’ or imprint in the soul and as involving a structured judgment, gives way to a distinction between mere ‘imaging’ and the soul’s active assessment of these images in judgments like ‘x is F’ or ‘it appears to me that x is F.’ Theaetetus’ first born is not the only child to be exposed through the argument of 184a–187b.27 Plato is also exposing his own ‘middle period’ theory of perception.

1.4 Heraclitus, Protagoras and the Unity of the Perceiving Subject When the thesis ‘knowledge is perception’ is first advanced in the Theaetetus 151, Socrates immediately relates the theory to Protagoras’ relativistic theory of senseperception (151e–152c), and subsequently to Heraclitean metaphysics of sensible flux (152e). Later on in the dialogue, at 160d, Socrates notes that the three theories, T, P and H, ‘coincide’: T implies the latter two tenets. Refuting T, then, can take the form of refuting either P or H respectively. Myles Burnyeat28 interprets the

26 I rely on the list compiled by John M. Cooper in his ‘Sense-Perception and Knowledge,’ reprinted in Fine (ed.): Plato 1, p. 359. 27 The imagery is ghastly, it’s true. The parallel between exposing children and uncovering flaws in arguments points to the less romantic side of Socrates’ midwifery. For the midwife-analogy to work in the Theaetetus, it’s crucial that Socrates is also a post-natal eugenicist. (See for instance 161a, where Socrates straightforwardly asks Theaetetus: ‘Is it your opinion that your child ought in any case be brought up and not exposed to die?’) Still, we can appreciate Socrates’ attempt to distinguish sound from flawed arguments without thereby buying into the eugenic basis of the analogy. Sensitive minds may take solace in the fact that Theaetetus’ first born is also referred to (151e) as a ‘wind-egg’ or ‘anemiaion’: it lacks the form of the father. 28 M. F. Burnyeat: ‘Knowledge is Perception. Theaetetus 151d–184a’ reprinted in Fine (ed.): Plato 1, Oxford Readings in Philosophy (Oxford: Oxford University Press, 1999), pp. 320–354. This is

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structure of the first refutation of T as a double argument, first proving P to be false (177c–179b), and subsequently refuting the metaphysics of H (179c–183c). The unnecessary double labor is explained by Plato’s eagerness not just to prove that T is mistaken, but to display the reasons why H and P fail respectively. At 151e–152c, Socrates interprets Protagoras’ famous homo mensura-sentence in terms of ‘appearing’ for a person. ‘Man is the measure of all things; of the things which are, that they are and of the things which are not, that they are not’ is thus transformed into the thesis ‘Things are for me such as they appear to me, and for you as they appear to you’ (152a). If it appears to A that x is F, then x really is F for A; conversely, if it appears to B that x is G, then x is G for B. One and the same wind29 may thus be said to be both cold and not cold at the same time, without thereby violating the principle of non-contradiction, since whatever properties the wind might have are relative to different perceiving subjects. Socrates sums up the position in terms of perception P: ‘things are for the individual such as he perceives them’ (152c). Perception, then, on the Protagorean model, is structured in the manner of beliefs. I perceive that the wind is warm. These beliefs cannot be false: Protagoras’ epistemology effectively precludes the possibility of erroneous judgment: I’m an infallible judge of my own appearances, and hence we’re all omniscient. Still, insofar as Protagoras has not ruled out the possibility of a world that exists independently of our perceptions, he cannot rest assured that ‘mistaken belief’ is a contradiction in terms. Introducing the Heraclitean ontology of flux, (H) at 152e, Socrates blocks this recourse once and for all. If everything is changing constantly, not retaining the same qualities for even an infinitesimally small stretch of time, then no things can strictly speaking be said to ‘be’ F or G; in fact, neither subject nor object are identical to themselves at any two times: ‘we are wrong when we say that they are, since nothing ever is, but everything is coming to be’ (152e). Socrates infers that on the Heraclitean-Protagorean model, sensible properties like ‘white’, ‘black’, ‘hot’ and ‘cold’ have no reality independently of our senseorgans: What we naturally call a particular color is neither that which impinges nor that which is impinged upon, but something which has come into being between the two, and which is private to the individual percipient (153e–154a).

As a consequence, no two perceptions of color are ever the same for two different subjects. But the flux doctrine does not merely undermine the identity of the objects of perception. It also undermines the identity of the perceiving subject. In fact, I cannot even at t2 check my own prior experience at t1, since I don’t retain my a slightly shorter version of Burnyeat’s discussion of Theaetetus 151d–186e in his introduction to M. J. Levett’s revised translation of the Theaetetus (Hackett, 1990). 29 Whether or not a Protagorean epistemology can accommodate conflicting appearances of the same x – ‘x appears F to A’ and ‘x appears G to B’ is not immediately clear. In order for conflict to arise, we must be able to identify the object whose features are in dispute. Thus, not all properties can be relative to perceivers – some underlying ‘substance’ must remain stable between observers. The Heraclitean metaphysics of becoming undermines any appeal to sameness, and hence to different appearances of the same object: the ‘paradox’ of conflicting appearances disappears.

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identity in the time that passes from t1 to t2. All I have are five distinct senses that mesh with the outside impression30 to create a momentary sensation of sweetness or whiteness or heat in the relevant sense-organs. As Burnyeat illustrates the upshot of this position, Heraclitus’ ontology makes nonsense of our belief in the unity of the perceiving subject: We may indeed speak of Socrates as tasting sweet wine, but only on the understanding that this Socrates cannot be the subject, just as the wine cannot be the object, of any other perception (159e) There is no more to this Socrates than his tasting tongue, and no more to it than is given by the statement that it is tasting this sweet wine now; so if, similarly, Socrates is to be identified with his eye when he sees something white, it follows that the Socrates who tastes something sweet at a certain moment is distinct from the Socrates who sees something white at that moment.31

This implication for our view of subjectivity will become relevant in Socrates’ second refutation of T. Plato’s second argument, the one in 184a–187b, relies on a proof to the effect that this ‘decentralized’ image of consciousness must be mistaken. Since it is a brute fact that we’re capable of judging that ‘This sweet thing is white’ there is a unity to our conscious experience that belies the decentralized model of the perceiving subject.

1.5 The Perceiving Subject as Wooden Horse The conclusion at 187a explicitly refers back to the two criteria of knowledge set out early in the dialogue. At 152c, Socrates infers that by equating knowledge and perception, Theaetetus must be maintaining that perception is about (1) ‘what is always’ and (2) that it is ‘unerring’ (tou ontos aei estin kai apseudes). These, then, are the defining features of epistêmê, the yardsticks of all subsequent attempts to clarify the notion: 1) Knowledge is about what is always 2) Knowledge cannot be false

The phrase ‘about what is always’ is ambiguous. On purely linguistic grounds, 1) could be interpreted either as the claim that knowledge is 1a) always about what is

or 1b) about what always is

The former points to a universal, and hence necessary condition for epistemic judgment, the latter focuses on the unchanging nature of any purported object of

30

The Heraclitean model makes it hard to describe the process, since we are forced to postulate a ‘Ding an sich’ that the theory does not allow for. 31 M. F. Burnyeat, ‘Plato on the Grammar of Perceiving,’ Classical Quarterly, NS 26 (1976), pp. 29–51.

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knowledge. If we favor 1b, the ontological reading, it is clear from the very outset of the dialogue that no object that affords of change can ever be known. Hence, given reading 1b, the two-world theory of forms and sensible flux is presupposed at the outset: only unchanging forms can properly speaking be known. However, the rest of the argument does not seem to presuppose this contentious doctrine, and the interpretation 1a does not rule it out. Thus, in the absence of strong evidence speaking in favor of 1b, we should be reluctant to introduce the theory of forms as a premise in the argument – Plato would hardly be happy with such a dogmatic procedure. How does Plato arrive at this revised theory of perception? At 184b–c, Socrates asks Theaetetus about the role of the sense-organs in perception. When we see white and black, or hear high and low tones, we obviously make use of our eyes and our ears, they readily agree. But are the eyes that with which we see (hô horômen) or that through which (di’hou) we see? The question is aimed toward a clarification of the ‘ergon’ or function of the sense-organs – are eyes and ears mere instruments in the perceptual process, or are they the agents or loci of perceiving itself? In keeping with Socrates’ own intuitions, Theaetetus favors the former alternative. We see through the eyes, not with them, and the same applies to the remaining four senses. No ears are capable of hearing qua ears – the auditory capacity belongs to the subject whose ears they are. The alternative scenario would be ‘very strange’ (deinon), Socrates maintains, since it implies that ‘there are a number of senses sitting inside us as if we were Wooden Horses (ei pollai tines en hêmin hôsper en doureiois hippois aisthêseis enkathêntai)’ (184d). The five men huddled inside the Wooden Horse all have separate consciousnesses, and there cannot be any unity to their experience. The men inside the horse cannot speak, since that would alert the Trojans to their plan, and they are presumably too far away from each other to use sign language. The horse itself is insentient – i.e. deaf and blind and without ability to taste, smell or touch. The problem with man qua Wooden Horse is, as Socrates points out, that it lacks ‘some single form, (mia tis idea) soul or whatever one ought to call it, to which all these converge – something with which, through the senses, as is they were instruments, we perceive all that is perceptible’ (184d). As Myles Burnyeat notes, the model of the five autonomous senses inside the Wooden Horse neatly parallels the notion of subjectivity that emerges from Heraclitus’ metaphysics of flux. On the Heraclitean model, there is nothing more to Socrates than his tasting tongue and his seeing eye: What he is at any given time t is what his senses perceive at that given moment. There is no one subject that ‘has’ different sensory experiences. The Kantian credo that ‘I think’ must be able to accompany all my representations is true only in the impoverished sense that ‘my’ experiences belong to one out of five warrior-senses inside the Wooden Horse. But that yields five centers of consciousness rather than one – precisely the absurd consequence of the third lemma of Mendelssohn’s argument. The ensuing argument demonstrates, convincingly, I think, that the Wooden Horse model does not provide an adequate description of perception or the perceiving subject. Socrates’ first move is to contend that (A) that though which we perceive properties such as ‘hot’, ‘hard’, ‘light’, ‘sweet’ and their opposites are instruments

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of the body. He then introduces a second assumption (B): we can’t perceive the proper objects of one bodily instrument through another. What I perceive through hearing, I can’t possibly perceive through sight and vice versa, and so on for all the different conceivable combinations of senses and their non-proper objects. If we take the truth of (B) for granted, we will also be willing to concede the following point to Socrates: (C) If you think something about both a proper object of hearing and a proper object of sight, say, that a particular sound or a particular color differ from each other, that each is identical to itself, that they are two, that they are, that they are like or unlike and so forth, these thoughts cannot be the exclusive product of perception (185a). For there is no special bodily instrument for these properties. Hence, if I judge that sound differs from color, my judgment presupposes something more than perceptual awareness.32 Still, we may already at this point want to pause to assess the viability of Socrates’ premises. Isn’t (B) patently false? Surely, it is possible to access the same properties both through sight and touch! Shape can be both seen and felt – otherwise such mundane activities as finding a light switch in the dark would be impossible. So it seems Socrates’ argument gets off on a screeching false note – and if (B) goes, then won’t (C) go down with it? But (C) is crucial for the argument Plato is about to make. Despite the obvious falsity of (B), Plato may still has the resources to circumvent the difficulty that arises. How do I know that the visual images my eyes provide and tactile sensations provided by my fingers are caused by the same object? The so-called Molyneux problem becomes relevant. In a letter to John Locke, reported in the second edition of An Essay Concerning Human Understanding, Molyneux asks us to imagine that a man, blind from birth, who has learnt by his touch to distinguish between a cube and a sphere, were to regain his sight. Two objects are placed before him on a table. Could this man, before touching the objects, tell the cube from the sphere? The answer, as far as Locke is conceded, is negative.33 There is no automatic connection between the qualia of the cube qua tangible object and

32 In his commentary to the Theaetetus 184b–186, F. M. Cornford warns against identifying ta koina with Aristotle’s common sensibles. ‘They are not to be confused with the “common sensibles” which Aristotle regarded as the objects of a common sensorium seated in the heart, namely objects perceptible by more than one sense, such as motion, shape, number, size, time. Plato does not speak of a “common sense” (koinê aisthêsis), but on the contrary insists that his common terms are apprehended, not by any sense, but by thought. The judgments involving them are made by the mind, thinking by itself, without any bodily organ.’ F. M. Cornford, Plato’s Theory of Knowledge (London: Routledge and Kegan Paul, 1935), p. 105. I agree with Cornford that Plato’s koina are apprehended by the soul (psuchê), not by any sense over and above the five mentioned. But Cornford wants to argue further that ta koina are ‘the meanings of common names – what Plato calls “Forms” or “Ideas”.’ Cornford’s identification of ta koina with Platonic forms makes it impossible to see how non-rational animals (and indeed most men) could have a unified consciousness, since they lack the ability to grasp forms. 33 John Locke, An Essay Concerning Human Understanding, ‘Of Perception,’ Book II, Chapter IX, 7.

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the qualia of the cube qua visible object. But if the senses can’t tell us that they are properties of the same object, how are we able to tell? Plato’s hypothetical retort is to insist that neither of the senses can discern ‘common’ properties such as ‘sameness’ and ‘difference.’ I can’t even formulate the question whether the object of one sense is the same as that of another sense if I restrict myself to employing bodily instruments. By modus ponens from (C), assuming (D), that we do think such things about particular sights, sounds, tastes and the like, it follows (E) that my awareness of qualities like ‘difference’ or ‘sameness’ and the like cannot be perceptual. But if that is the case, what is the instrument ‘through which’ such ‘common properties’ are revealed?34 Theaetetus’ answer corrects Socrates’ tentative suggestion that we recognize these properties ‘through’ an instrument: ‘All I can tell you is that it doesn’t seem to me that for these things there is any special instrument (organon idion) at all, as there is for the others. It seems to me that in investigating the common features (ta koina) of everything the soul functions through itself (autê di’hautês)’ (185d–e). The soul is not in the service of yet another cognitive faculty when it perceives such qualities. This gives rise to the conclusion of the argument, (F): The soul itself is the locus and sole agent of any cognitive activity that involves the use of or reference to ta koina. Socrates completes the discovery by adding that not only does the soul consider some things through itself, the soul is also the true subject of awareness that passes through the senses. It is that with which we see, hear, taste, touch and smell. Perception in the strict and philosophical sense happens through the senses, which are impinged upon by their proper sensibles. But judgment about these sensibles is an exclusive function of the soul, whether it’s a judgment that ‘this is white’, that ‘this is sweet’, that ‘sweet differs from white’, that ‘the whiteness and sweetness are two different properties’ and so on. Summary of the Wooden Horse argument: (1) The five senses – that through which we perceive properties such as ‘hot’, ‘hard’, ‘white’, ‘sweet’ and their opposites – are instruments of the body. (2) We can’t perceive the proper objects of one sense through another sense. (3) If we think something about both a proper object of sight and a proper object of taste (that this white thing is sweet, that white differs from sweet, and so forth), this is not in virtue of a perception of both properties through either sense. (4) But we do think such things about particular sights, tastes and the like. (5) So whenever we have a thought that includes reference to a ‘common property’, this is not ultimately in virtue of any of the five senses, which are instruments of the body. (6) So common properties (koina) aren’t perceptible. (7) Rather, the soul considers the common properties through itself. (8) The soul is ‘that one form’ (mia tis idea) with which we consider the proper objects that are given through the five senses.

34

I here rely on a reconstruction suggested by Charles Brittain.

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The debate about the nature of ta koina – whether apprehending them is apprehending forms, as Cherniss and Cornford have held, or whether apprehending them rather requires a lower-level ability to apply common properties to a sensible manifold, as critics such as Burnyeat and Cooper have argued – is a debate that I cannot fully explore in the present paper. Those who read the passage in light of the Phaedo 79d, where Plato states that ‘the soul investigates by itself when it passes into the realm of the invisible forms,’ are likely to opt for the former reading. But the function of the soul in the Theaetetus passage is supposed to be to judge perceptions – krinein. It seems excessive to require apprehension of forms in order to judge that ‘This sweet thing is white.’ Apprehending forms would then be a precondition even for false judgment and belief (doxazein) (187a). And this is hardly a Platonic position. The identification of the perceptual activity of the bodily senses with knowledge fails, because the bodily senses fail to judge their objects, as the bodily senses lack the common properties.35 The suggestion that knowledge requires judgment gives rise to the conception of Theaetetus’ second child, the thesis that ‘Knowledge is true belief,’ which occupies the interlocutors in the next part of the dialogue. The notion of forming an opinion is also central in Socrates’ classical definition of thinking at 189e–190a: ‘a talk which the soul has with itself about the objects under investigation.’ When the soul arrives at something definite, i.e. when it ‘affirms one thing consistently and without divided counsel, we call this a judgment.’ We have strong contextual evidence, then, that by calling ‘ousia’ a ‘common property’, Plato is not claiming that ‘grasping being’ in the sense of intuiting forms is the function of the soul when presented with the evidence of the senses.

1.6 The Wooden Horse and Achilles Burnyeat held that the Wooden Horse passage contains ‘the first unambiguous statement in the history of philosophy of the difficult but undoubtedly important idea of the unity of consciousness.’ The question is whether Plato takes the further step

35 As Michael Frede writes, Plato’s point in introducing the narrow notion of perception as a purely passive affection of the body is to ‘untangle the conflation of perception, appearance, belief, and knowledge with which the dialogue begins at 151d.’ Frede: ‘Perception in Plato’s Later Dialogues,’ reprinted in Fine (ed.): Plato 1: 377–379. A comprehensive physicalist notion of vision is developed at Timaeus 45: ‘Now whenever daylight surrounds the visual stream, like makes contact with like and coalesces with it to make up a single homogenous body aligned with the direction of the eyes. This happens whenever the internal fire strikes and presses against an external object it has connected with. (. . .) It transmits the motions of whatever it comes into contact with as well as whatever comes into contact with it, to and through the whole body until they reach the soul. This brings about the sensation we call seeing.’ Sense-impressions are presented as ‘images’. The liver – the locus of appetite – is singled out as the ‘perceptive’ part of the soul in virtue of its smooth, reflective surface. The spleen performs the part of a dust-cloth (72c), ‘wiping’ the mirror of the soul. The Timaeus gives different termini for sense-perception in different passages at 64–68: both the liver and ‘center of consciousness’ (64b) are mentioned.

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(Plotinus’ step) of inferring that the unity of consciousness presupposes the metaphysical simplicity of the thinking or perceiving subject. Socrates identifies ‘some one form (mia tis idea), soul or whatever one ought to call it, to which all these converge – something with which, through the senses, as if they were instruments, we perceive all that is perceptible’ (184d). The unity of the soul secures the unity of perceptual experience. Knowing Plato’s metaphysical commitments from the Phaedo it’s not unreasonable to argue ex silentio that he conceives of the soul as a substance in the Theatetus. For he calls it a form (idea), and a form may very well be a substance in Plato’s ontology. But significantly, Socrates does not insist on the simplicity of the soul substance in the Theaetetus. All that is explicitly required is its unity. If Plato had been on the track of the Narrow Achilles here, why did he not articulate the argument in terms of simplicity rather than unity? The most convincing answer that I can give is that he rejects the assumption that the unity of the soul requires its simplicity. Just as the body is one, although it consists of parts, the soul may be one, although it consists of parts. It’s hardly news that Plato subscribes to a theory of a partitioned soul in his middle and late dialogues. In the Phaedo, bodily desires for food, drink and sex are said to belong to the body, not to the soul. But in Republic IV, Plato reverses his position: appetitive desires belong to a distinct part of the psychê, the part named after them, to epithumêtikon. Relying on a quasi-physical principle of opposites (‘the same thing will not be willing to do or undergo opposites in the same part of itself, in relation to the same thing, at the same time’ (436b)), and the reality of a specific kind of motivational conflict, Plato concludes that the soul is tripartite. But although the soul consists of parts, these parts are not thought to be internally divisible ad infinitum.36 Rather, the internal unity of a part is preserved through its distinctive function – ergon.37 There’s no need to ask whether a part of the part could perform that function, for Plato’s argument moves from observation about a characteristic function to the existence of a part of soul realizing that function. Insofar as it serves this purpose, the question of whether the part is itself divisible is moot. The most fundamental observation to be made about parts of soul is not, then, that they are infinitely divisible magnitudes, like parts of undifferentiated matter (what Aristotle calls ‘homeomerous’ stuff), but that they are distinguished by the differing functions of the soul that they make possible. Burnyeat notes that the ‘with’ idiom38 that distinguishes the function of the soul from the instrumental function of the senses at 184b–c, is the same idiom that he employs to characterize the functions of the different parts of the soul – the appetitive (to epithumêtikon), the spirited (to thumoeidês) and the reasoned (to logistikon) – 36

As T. H. Irwin has argued in Plato’s Ethics (Oxford: Oxford University Press, 1995), Chapter 13, Republic IV: The Division of the Soul. 37 This has led some commentators to conclude that talk of parts is merely metaphorical, and that they simply refer to different functions of the soul. For a discussion of this question sympathetic to the opposite view, see Hendrik Lorenz, The Brute Within (Oxford: Oxford University Press, 2006). 38 The construction is one where the thing ‘with which’ we act is put in a dative case. The instrumental meaning is conveyed by dia + genitive case.

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in the Republic 436a. Socrates asks Glaucon: ‘Do we learn with one part, get angry with another, and with some third part desire the pleasures of food, drink, sex and the others that are closely akin to them? Or, when we set out after something, do we act with the whole of our soul, in each case?’ His answer is, of course, that we do so with different parts of soul. But if the soul consists of parts, why doesn’t the unity of the subject dissolve into separate, autonomous sub-agents? If we can’t perceive with a number of senses, since it would dissolve the unity of our consciousness, why should we be able to ‘desire’ with different parts of our souls and still remain a person? The idea that there are five separate ‘sub-agents’ with which we see, hear, touch, smell and taste cannot be blown off as ‘very strange’ (deinon) in the Theaetetus, if it’s precisely the same idea of division of labor is accepted as part and parcel of the partition-argument in the Republic. To see why the cases are not, in fact, parallel, we need to pay attention to a crucial difference between the cognitive capacities of the five senses and the three parts of soul respectively. The five senses are incapable of grasping anything but their proper sensibles. The tongue cannot appreciate color, the eyes cannot notice sound, the ears are impervious to taste. The matter stands differently with individual parts of the soul. Plato repeatedly refers to the rational part as issuing commands to the spirited and appetitive parts, and claims that an individual man is moderate ‘because of the friendly and harmonious relations between these same parts, namely, when the ruler and the ruled agree in common (homodoxôsi) that the rational part should rule and don’t engage in civil war against it’ (442d). In other words, the parts are capable of communicating with each other, and may share opinions about what the proper rule is. The rational part can assess the opinion of appetite and spirit, appetite can accept, if not fully understand, the dictates of reason, and the spirited part can accept the opinions of either parts, although it should be an ally of reason when it does its job excellently. A well-functioning soul, just like a well-functioning city, is one in which all the parts do their own work, but at the same time ‘sing the same song together.’ In a moderate soul, as in a moderate city, ‘the same belief is present in the rulers and the ruled about who ought to be the rulers’ (Rep. 431d). It appears, then, that the unity of the soul is preserved through the proper consonance of the individual parts. A person properly governed by reason will not experience the kind of discord that plagues the akratês. So, if we apply the Wooden Horse model to Plato’s psychology, what matters is not that there are several warriors inside the horse, but that the right warrior is in charge. Plato’s partition of the soul is compatible with unity of consciousness. When epithumia has our knees quake in fear, and our skin turn white with terror, we need a wise Odysseus to boost our morale. When thumos urges us to spring out of the horse before it’s time, reason should hold us back.39 Autonomy and unity of consciousness, on this model, is a matter of being governed by reason. If 39

The state of the men inside the Trojan Horse seems to have ranged from over-eagerness to fear and trembling, if we are to believe Odysseus’ report: ‘While our picked Argive crew still rode that hollow horse Epeios built, and when the whole thing lay with me, to open the trapdoor of the ambuscade or not, at that point our Danaan lords and soldiers wiped their eyes and their knees began to shake, all but Neoptolemos. I never saw his hand brush one tear away. Rather, he prayed

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the line of command is correct, and all soldiers heed the decision reached by reason, all the parts of the soul converge to form a single, unified person. In that case, the warriors inside the horse will stand as one man.

1.7 Review and Conclusion It’s time to assess my evidence against Mijuskovic’s view that Plato was the first philosopher to articulate the Achilles argument. I first tried to show that the affinity argument in the Phaedo does not express the Narrow Achilles, since it does not rest on considerations about the unity of thought or the unity of consciousness. I then considered what I, with Burnyeat, take to be the first extant articulation of the idea of the unity of consciousness, the Wooden Horse passage in the Theaetetus. I concluded that although Plato insists that the soul be one, he is mum on the question of the simplicity of the unified soul. To be sure, Plato’s argument shares certain similarities with the third lemma of Mendelssohn’s, but since he does not explicitly tie the unity of the perceiving soul to its simplicity, he stops short of articulating the Narrow Achilles. Plato’s partition of the soul in Republic IV indicates that he is unfazed by worries that only a simple soul is truly unified. Breaking with the psychological model presupposed in the Phaedo, Plato here insists that the human psyche is composed of three functionally distinct parts (merê) (442b) or forms (eidê) (435c). If Plato was the first philosopher to hold that unity of consciousness requires simplicity of soul as Mijuskovic urges, he failed to show how his new model would handle the challenge of the Wooden Horse, a rather brazen omission. If Plato were the progenitor of the Achilles, he might be expected to recall that later on. If, on the other hand, Plato never assumed that unity requires simplicity, this putative omission is easier to explain, for he would not have any reason to think that the tripartite psychology is inherently inimical to his argument for the unity of the perceiving soul in the Theaetetus. I believe Plato’s silence on the issue speaks volumes. Would Plato have accepted the first lemma of Mendelssohn’s argument – that an extended soul would be infinity divisible into smaller and smaller parts, so that it would be impossible to determine in what part of the part a thought inheres? I find even this doubtful. First, in the Timaeus he appears to think that matter consists of ultimate simples: though Plato certainly rejects atomism as an ultimate explanatory principle, he equally rejects the hypothesis of matter’s infinite divisibility. Second, I don’t see any reason to saddle Plato with the thought that a property of the whole is necessarily a property of its parts. Why assume that just because a whole eye has the ability to see, half an eye has the same ability? In the absence of conclusive evidence that Plato accepts this kind of (fallacious) argument, we should not foist it on him. Third, a function may be realized in matter without being essentially material. In

me, hand on hilt, to sortie, and he gripped his tough spear, bent on havoc for the Trojans’ (The Odyssey book XI, 622–632, translated by Robert Fitzgerald, Vintage Classics, 1961).

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fact, it would seem that Plato’s partition argument in Republic IV is compatible with non-reductive materialism about the soul: the soul is the form (eidos) of the body, as Aristotle would later insist. Although some psychological functions may be realized in matter, as Plato seems to suggest in the Timaeus,40 the soul is not reducible to matter. Plato agrees with Plotinus that the soul is not essentially material. But even something that is not essentially material may be partitioned or even realized in matter. The soul is not essentially an extensive magnitude (megethos), but that still leaves Plato several options for preserving unity in a partite soul. All in all, then, the passages I have examined do no confirm Mijuskovic’s view that Plato recognized an argument from the unity of thought to the simplicity of soul – the Narrow Achilles. What we find is an argument from the unity of perception to the unity of the perceiving subject. But this is all in good, Kantian taste. Granted, there may be other passages that demand our attention. I have considered the ones that strike me as the best candidates for finding the Achilles argument in Plato. Despite many similarities, the results were negative. But if Plato does not articulate the Narrow Achilles, he does not articulate the Broad Achilles either. It seems then, that we still lack evidence for thinking that Plato should be one of the philosophers that stand accused by Kant of articulating a paralogism, the paralogism he calls ‘the Achilles of all rationalist arguments in the pure doctrine of the soul.’

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In the Timaeus, Plato locates different parts of soul in different parts of body. The offspring of the demiurge encased the ‘immortal’ part of the soul ‘within a round mortal body,’ i.e. the head (69c), while they place the mortal soul – the spirited and appetitive parts – in the chest and the trunk. The locations reflect the relations between the parts: ‘since one part of the mortal soul was superior to the other, they built the hollow of the trunk in sections (. . .) the spirited part they settled nearer the head, between the midriff and neck, so that it might listen to reason and together with it restrain by force the part consisting of appetites should the latter at any time refuse outright to obey the dictates of reason coming down from the citadel’ (70a). But this spatial distribution of functions does not by itself threaten the unity of the soul as far as Plato is concerned. Granted, Plato sometimes muddies the waters by likening appetite to a ‘many-headed and multifarious beast’ and spirit to a ‘lion’, while reason is the human being proper (Rep. 588c–d), which certainly makes it sound as if the unity of the person dissolves. If a soul is well-ordered, the unity is preserved. A greater threat is Plato’s tendency to write as if the appetitive and spirited part themselves have a rational part that may understand and concur with the judgment of reason. This may entail that these parts have a rational part of their own, a concession that which would land Plato in a vicious regress. See T. H. Irwin, Plato’s Ethics, pp. 217–222 for a discussion of the unity of a part of soul and the relations between them.

Chapter 2

Aristotle on the Unity of Consciousness John Thorp

Broadly understood, the Achilles Argument has two steps. The first establishes the unity of the soul on the basis of the experienced unity of consciousness; the second establishes the immortality of the soul on the basis of its unity: what is simple cannot decompose.1 More narrowly understood, the Achilles is really just the first of these steps, from the unity of consciousness to the unity of the soul. Although these themes are swirling around in Aristotle’s ruminations about soul, it is very interesting that he does not advance the broad Achilles Argument. Not only does he not advance it; he might actually be said to repudiate it, for he asserts its premise, and he denies its conclusion – that is, he seems to take the first step of proving the unity of the cognizing soul, but he denies its immortality.2 How can this be? Certainly, it is not that Aristotle is resistant to the idea that simplicity confers eternity: that all perishing is decomposition, and that what is partless cannot decompose. It is this thought, for example, that underlies his quest in Book VIII of the Metaphysics to show that essences are atomic after all, despite their appearance of being composed of parts: genus and differentia. It is this thought that leads him to associate the partlessness and the eternity of the prime mover at the end of the Physics. No, the reason for his immunity from seduction by the Achilles Argument lies elsewhere. When Aristotle considers the question of the immortality of the soul or the mind, its simplicity is never in play; he conducts that inquiry in terms, mostly, of J. Thorp Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 85767, Fax: (519) 661-3922 e-mail: [email protected] 1 In some versions of the argument the sequence runs from simplicity through immateriality to imperishability. 2 Notoriously, of course, Aristotle allows that the active mind – or what might better be called the productive mind – is immortal and eternal. But there is no agreement in sight as to just what the active mind is: hypotheses range from God to a person’s power to focus attention, the power to abstract. We will contrive to steer clear of those irresolvable debates in this article. What is not in doubt is that the passive mind, the bearer of knowledge, is perishable. And an upshot of this is that even if an active mind survives bodily death, memory does not (430a 24).

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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impassibility: an impassible mind would be immortal.3 Why, one wonders, does he not consider simplicity in this context? Plato, as Karen Nielsen has shown in Chapter 1, above, had laid the tracks of this argument so invitingly; why does Aristotle avoid traveling down them? To be sure, Aristotle takes the first steps down them. When he raises the question by what sense we discriminate sweet from white – the question that gives rise to the doctrine of common sense – he seems to be embarking on the Achilles. The answer is that there has to be ‘some one thing’ that discriminates these, since it cannot be done by taste or sight themselves.4 He even advances the thought experiment that often opens the Achilles: not to postulate a single cognizer beyond the individual senses would be as though I were aware of the sweet and you of the white. . . .5 But then his thought takes a surprising turn. Instead of pressing on about the perfect and indissoluble oneness of the ultimate cognizer, he qualifies that oneness: the cognizer must be one, yes, but it must also be two. It must be single in one way, and in another way it must be multiple. For, to make the judgment that sweet is different from white it must be one; but to be aware of sweet and white separately and simultaneously it must be two! Far from reaching an Achilles-like conclusion that the cognizer must be simple, partless, indivisible, etc., Aristotle seems to conclude that it must be divisible, although a unit. The upshot of this is that the reason Aristotle does not accept the broad Achilles argument is that, when one looks closely at it, he does not even accept the narrow Achilles argument. His view about the unity of the cognizer turns out to be very subtle and elusive. I will try to figure it out.

2.1 Aristotle’s Argument Three principal texts are relevant here, two from Book III of de Anima, and one from Chapter 7 of de Sensu.6 Although the texts are linguistically very difficult – crabbed and telegraphic and encumbered by a dizzying cascade of textual variants7 – nevertheless it does seem possible to stand back from them and see that, broadly, they are all urging the same thing. There is enough overlap of language and of images that we can see that Aristotle is trying to formulate the point that the ultimate 3

For example, de Anima I, 4, 408b18 ff. de Anima III, 2, 426b18 5 426b19 6 More narrowly, the texts in question are: de Anima III, 2, 426b10–427a15; de Anima III, 7, 431a20–431b1; de Sensu, 7, especially 448b17–449a22. 7 Some of the flavor of these difficulties may be seen if we assemble a few of the commentators’ remarks about the particularly challenging passage at 431a21 ff. Rodier, Aristote: Traité de l’âme, p. 501, writes, grandly, ‘. . .ce passage, dont l’obscurité est célèbre. . . .’; Wallace, Aristotle’s Psychology, p. 280, writes, ‘This paragraph is full of almost hopeless difficulties. . . .’; Ross, Aristotle: de Anima, p. 305 writes, ‘This is a difficult passage, of which only a tentative interpretation can be offered.’ 4

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cognizer both is and is not unitary. Our attempt will be to understand in what way he sees the cognizer as single and in what way he does not. In my presentation and discussion of the matter I won’t try to follow the development of any one of the three texts in particular. Rather, working from a sort of loose amalgam of the three, I present what seems the clearest logical ordering of Aristotle’s thought. I am guided by a logic of exposition rather than one of discovery. But first, let me set out a number of general points about these passages. The first point is that all three of them are concerned, it seems, not with knowledge in the strict sense, but with sense-perception.8 This may initially make them seem irrelevant to the question of the Achilles argument, which seems to be about thought as such. But they are not irrelevant: Aristotle says explicitly that the same requirement respecting the unity of the cognizer belongs to judging, to thinking and to perceiving.9 The account, it seems, is meant to be quite general with respect to the cognitive operations. The second point is this. Aristotle is interested by two different cases. One case is the perception of objects10 that belong to different genera: sweet and white, black and bitter; how is it possible for one and the same cognizer to be simultaneously aware of these, and to distinguish them? But he is also interested in the more difficult case of objects that belong to the same genus, but are contraries: black and white, sweet and bitter. Call these latter cases homogeneous11 contraries, and the former ones heterogeneous attributes. The third point is that Aristotle is not driven just by the phenomenon that one can perceive both sweet and white; he notes the further point that one can realize and indeed assert that these two objects are different from one another. So the phenomenon driving the theory is not just that one can be aware of these two objects; it is also that one can be aware that they are different objects. The fourth point is that Aristotle very explicitly rejects any solution to the problem that would consist in allocating the two perceptions to different moments of time.12 It is rather coinstantaneously that one is aware of the sweet and the white, 8

Some commentators have thought that, in the passage of de Anima, III, 7, it is ideas, not percepts, that are being discussed: the idea of sweet and the idea of white. In favor of this view is the fact that Chapter 7 is, broadly, about thought – certainly its opening remarks are about knowledge. But it has long been recognized that the chapter – to quote Ross, Aristotle: . . . de Anima, p. 303 – ‘is not a connected discussion but a series of scraps put together by an early editor. . . .We must suppose that an early editor found these scraps in Aristotle’s Nachlass, and simply strung them together in order that none of the Master’s words should be lost to posterity.’ 9 de Anima III, 2, 426b21. 10 In these contexts the term ‘object’ generally means the attribute or property that is perceived, rather than the thing whose attributes are perceived. 11 ‘Homogeneous’ is here used in the sense ‘being of the same genus’; the more normal English term would probably be ‘congeneric’, but ‘homogeneous’ and ‘heterogeneous’ have standardly been used by commentators in the present context. 12 The point is not idle. There had long been a puzzle in the theory of music about how one can hear concords, that is, how one can hear two notes sounded together – surely the one note should drive out or drown out the other. A traditional solution to this puzzle, which one finds, for example,

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and aware that they are different. He goes further: ‘it asserts now that the objects are different now.’13 The final point is that we cannot rely on Aristotle to use a number of crucial words here in a consistent and precise way. It is a particular problem that there are no perfectly unambiguous words for undivided vs indivisible, separable vs separate. The Greek word diaireton, a verbal adjective, may mean divided or divisible. The Greek word chôriston may mean separate or separable. Problems of this sort are endemic to Aristotle, of course, and they are frustrating. But at least they are familiar. It follows that very often the best way to get at the sense of a passage may not be to attempt a really close reading right off the bat: it may be wiser to stand back a bit and let the vision blur, so that one gets the general message. Now the general message of all three texts is, as we said, that to account for these phenomena, the cognizer has to be a unit, but not straightforwardly so. It has to be, in one way, one, and in another way, two (or, presumably, more). I find, in the three texts, six ways in which Aristotle expresses the contrast between the way of being one and the way of being more than one: 1. (de Anima III, 2, 427a1) that which distinguishes is unified and undivided and inseparable in number, but divided in being.14 hama men kai arithmô adiaireton kai achôriston to krinon, tô einai de kechôrismenon 2. (de Anima III, 2, 427a3) it is as though the divided [cognizer] perceives disparate objects, but it does so qua undivided. esti dê pôs hôs to diaireton tôn diêrêmenôn aisthanetai, esti d’hôs hê adiaireton 3. (de Anima III, 2, 427a5) it is divided in being but undivided in place and number. tô einai men gar diaireton, topô de kai arithmô adiaireton 4. (de Anima III,7, 431a19) The final [cognizer] is one and a single mean, though its being is multiple. . . . to de eschaton hen, kai mia mesotês, to d’einai autê pleiô. . . . 5. (de Sensu, 449a17) the common sense is one and the same in number, though in its being it is different, reflecting different genera and species [of its objects]. to auto kai hen einai arithmô to aisthêtikon pantôn, to mentoi einai heteron kai heteron tôn men genei tôn de eidei 6. (de Sensu, 449a19) different objects would be perceived by one selfsame cognizer, but not selfsame in essence (logos). hôste kai aisthanoit’ an hama tô autô kai heni, logô d’ou tô autô.

in Plato (Timaeus 67b), was the idea that high-pitched notes travel faster than low-pitched ones, so the high note in the concord will reach the ear before the low one, and will expire before the low one expires. It is an interesting confusion between rate of vibration and rate of travel in sound. 13 de Anima III, 2, 426b28. 14 Unless otherwise noted, the translations are my own.

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So the ultimate cognizer is both one and many, one in number and in place, but plural in ‘being’, in essence. To judge that white and sweet are different the cognizer has to be somehow divided so that it can register both white and sweet; but it must be unitary so that it can issue the judgment that they are different. It has to be one, but has also to be divisible. It has to be one, but it need not – indeed it must not – be simple. In the de Sensu chapter Aristotle struggles with this idea. He rejects an initial thought that white and sweet might fuse into one attribute – the way, we might say, that blue and yellow fuse to make the single object green.15 He starts to settle for the view that perceptions of different objects simply cannot be coinstantaneous despite appearances to the contrary.16 But then he comes to the realization that, in fact, the coincidence of two heterogeneous forms in one cognizer need not be mysterious at all.17 A thing that is white and sweet – a lump of sugar, for example – meets the criterion perfectly. It is one in number and in place, but it is diverse in its ‘being’: it is white and it is sweet. If one thinks of the cognizer as replicating the perceived thing, then one can see a straightforward sense in which it might be one in number but various in ‘being’. There is no more difficulty about a cognizer being receptive of sweetness and whiteness at the same time – and being so in actuality not just in potency – than there is about a lump of sugar being both white and sweet at the same time. Nothing could be more familiar. Now, for sure the term ‘being’ – various in ‘being’ – strikes the reader as oddly grandiose here; we also find the word logos, which may be rendered as ‘definition’, or, more neutrally, as ‘account’. Perhaps the idea is something like this: the lump of sugar is one in number, but there are various things that it is: it is sweet; it is white; it is crumbly. . . . The ‘being’ in question just reflects the use of the verb ‘to be’ as the copula. In our account of the sugar we mention the various things that it is. . . .white, sweet, etc. This is my best guess, at this point, for understanding the terminology. However that matter of terminology may be, the general idea works out quite well in the case of heterogeneous objects. The cognizer is in a sense one, numerically one, but it is not one in being: it can don18 the quite different forms of sweet and white, in actuality, and that at the same time. But the case of homogeneous contraries presents a much steeper grade of difficulty.19 It doesn’t seem theoretically possible for a thing to be both black and white, to assume contrary properties at the same time. We must remember that 15

de Sensu, 7, 447b10 ff. & 449a7. There is an interesting discussion of these matters in William Charlton, ‘Telling the Difference between Sweet and Pale’, Apeiron, 1981, 103–114. 16 de Sensu, 7, 447b7 ff. 17 de Sensu, 7, 449a13 ff. 18 I take this striking image from Rodier (p. 386): ‘Il résulte de là que, puisque sentir c’est s’identifier à la forme sensible, le sentant indivisible doit revêtir, dans le même temps, des formes contraires, ce qui paraît impossible.’ 19 Curiously, in the discussion in de Sensu, at least in its earlier parts, Aristotle clearly considers that the case of heterogeneous objects is more difficult to accommodate than that of homogeneous contraries.

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in Aristotle’s hylomorphic theory, perception is the imprinting of the form of the perceived object upon the sense; in the case of perceiving black and white simultaneously, then, the sense would have to be both black and white, would have to receive contrary forms at the same time. Aristotle quickly rejects what might have been the expected way for him to deal with this, that is, by saying that a thing can be potentially sweet and potentially bitter at the same time;20 for awareness requires that the object of perception be actualized in sense; indeed the whole doctrine of sense perception is that it is the actualization of potentials in the sense organs. So, in order to explain the simultaneous awareness of homogeneous contraries, and our judgment that they are contrary, Aristotle is stuck with having to say that the cognizer receives contrary forms at one and the same time, or, as he puts it explicitly, is affected by contrary movements (kinêseis) at one and the same time. And this looks very much as though it would violate the Principle of Non-Contradiction.21 How can this be? And here Aristotle pulls a rabbit from the hat. He says that the case is like that of a point or limit: 7. (de Anima III, 2, 427a9) But as with what is called a point, just as it is both one and two, so it is both indivisible and divisible. all’ hôsper hên kalousi tines stigmên, hê mia kai duo, tautê [kai adiairetos] kai diairetê 8. (de Anima III, 2, 427a13) So far forth then as it takes the limit as two, it discriminates two separate objects with what in a sense is divided:22 while so far forth as it takes it as one, it does so with what is one and in a single moment of time. hê men oun dis chrêtai tô perati, duo krinei kai [kechôrismena] estin hôs kechhôrismenôs; hê de heni, hen kai hama 9. (de Anima III, 7, 431a23) it [the cognizer] is one thing, in the way that a boundary is esti gar hen ti, houtô de hôs ho horos23

This is what Aristotle gives us; we must see what we can make of it.

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For discussion of this same idea in other thinkers, see Jean-Pierre Schacter’s chapter on Locke, in this volume. 21 Here and in what follows I assume it proved that to predicate contrary properties of a subject (at the same time and in the same respect . . .) is to violate the Principle of Non-Contradiction. 22 Here the textual variants are too many to permit a secure reading. But it is certain that the analogy of the point or limit is invoked. 23 Averroes, Averrois Cordubensis Commentarium Magnum in Aristotelis De Anima Libros, p. 471, understands the term horos here to mean ‘definition’. While this is indeed, in the abstract, a possible meaning of the word, surely given the discussion of points and limits in III, 2, ‘boundary’ – understood as a mathematical term – is a more reasonable translation.

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2.2 A Preliminary Question This remarkable proposal certainly invites some questions and some comments. The first question is this. To what entity, exactly, is Aristotle meaning to ascribe this subtle two-in-oneness? Is it the organ of common sense? Is it the faculty of common sense? I have deliberately tried to hold this question at bay by supplying the phrase ‘ultimate cognizer’ or ‘cognizer’ in my presentation of the argument. But the question will not go away. If what Aristotle is speaking about is an organ, then the business about the point or limit seems troubling. Is Aristotle saying that the organ is like a limit, in this particular, that it can be one in number while being two in ‘being’? In that case we want to know more about the material realization of this possibility. Is the point mentioned just to make the general claim that there can be cases of oneness in number but twoness in being? Or is the analogy meant to be a much closer one? If, on the other hand, what has this twoness-in-oneness is the faculty, whether of common sense or of knowledge, then the matter seems much more metaphorical and much less troubling. I’m not at all sure what the principle of individuation of faculties is, so some wobble over whether a given faculty is one or two would not distress me.24 We don’t get much guidance from the text in our attempt to tackle this question: Aristotle’s phrasing seems to be systematically ambiguous. Sweet and white are presented ‘to some one thing’ (heni tini); ‘that which distinguishes (to krinon) is unified. . . .’; ‘the perceiver of everything (to aisthêtikon pantôn). . . .’; and so forth. It almost seems that Aristotle is engaging in methodical indirection. In fact, I think that is exactly right. He is an acute observer of the anatomy of the special organs of sense,25 but he can only guess at the nature of the common organ, or of the physiological apparatus of imagination and memory. So we are to read his discussions of these as trying simply to say what, minimally, must be true of that apparatus and its functioning: it has to be such as to allow us to be aware of bitter and sweet simultaneously and to judge that they are different, and this, in turn, requires a certain oneness together with a certain twoness in the apparatus and/or its manner of functioning. Even, however, if we allow Aristotle this vagueness about just what is the analog of the point, the analogy seems not altogether satisfactory.26 Do we not, however we turn matters, end up having to say that the subject dons contrary forms at the same time? Have we really made any progress with the puzzle that Aristotle’s analysis sets us? The turn that Aristotle takes away from the Achilles Argument seems to lead into an impassable swamp of contradiction. 24

Alexander, Quaestiones 97, 12 ff., for example, argues that it is the faculty, not the organ, that is being discussed. 25 His observation of the anatomy, and his suggested physiology, of the ear are particularly remarkable: de Anima II, 8. 26 D.W. Hamlyn, tr. & comm., Aristotle, De Anima, Books II and III, with passages from Book I, Oxford, Clarendon Press, 2002, p. 128, comments, drily, that the analogy ‘is not perspicuous in its implications, to say the least.’

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2.3 Four Dodges In the commentaries there have been, broadly, three ways of dodging this impasse. One, which I might dub the ‘neoplatonic’ way, has been to argue something of the following kind. While it is true that in the realm of bodily things a subject cannot be characterized by two contrary forms at the same time, in the realm of intentionality, which is not bodily, this constraint does not apply. There is simply no difficulty in having two contrary forms present intentionally (gnôstikôs). And so, by the wave of a wand, the problem is solved.27 Of course, though, this won’t do as exegesis of Aristotle. As has very often been observed, the notion of a nonbodily intentional realm is simply missing from Aristotle. Whether this is ultimately a virtue or a vice in his account is subject to debate, but, interpretation of his texts must stay within the bounds of his clean parsimonious thought. The second dodge – which one finds first in Themistius and most recently in Hicks – has been to say that when one is aware of the difference between black and white, say, one is really aware not of two things but only of one: the difference. There is really, after all, only one object of perception in such a case, so there is no need to suppose that the cognizer is subject to two contradictory ‘movements’.28 But of course Aristotle repeatedly insists that, in some sense or other, the cognizer is bifurcated. The third way of dodging the impasse has been to quietly give up Aristotle’s fundamental working hypothesis that perceiving or knowing is to be understood as passive; commentators have been tempted to this from as early as Alexander to as recently as Hamlyn. Alexander writes: A body, indeed, cannot be subject at the same time and in the same part to several different affections, because contraries cannot coexist. . . .but there is nothing to stop the sensitive faculty from distinguishing them, for distinguishing is not undergoing an affection.29

And Hamlyn writes: These objections depend, of course, on the idea that perceiving something is being affected or moved by it. It may be that the next section with its emphasis on judgment is meant to undermine that idea, but if so Aristotle does not make the point really clear.30

But this way around the impasse isn’t really playing the game; it is changing the rules: it requires that we give up what seems like the basic working hypothesis of Aristotle’s enquiry into perception and cognition, the hypothesis, one might say, of the passivity of cognition. He acknowledges that hypothesis explicitly at 427a8:

27

See, for example, Sophonias 114, 38ff. Themistius, 114; Hicks, p. 451 29 Alexander, Quaestiones 97, 19–25; oddly, though, he had earlier said that judging and perceiving are the same: 94, 32. 30 Hamlyn, p. 127–128. 28

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A thing cannot be at once white and black, and therefore cannot at one moment be subject to (paschein) the forms of white and black – if that is the sort of thing that perception and knowledge are.31

A fourth possible dodge, which to my knowledge no commentator has embraced, would be to deny another of Aristotle’s explicit hypotheses. He writes at de Sensu 7, 448a2: Again, if the stimuli (kinêseis) of sense derived from contraries are themselves contrary, and if contraries cannot be conceived as subsisting together in the same individual subject, and if contraries, e.g. sweet and bitter, come under one and the same sense-faculty, we must conclude that it is impossible to discern them coinstantaneously.32

The first conditional clause in this passage might be called the hypothesis of logical isomorphism, that is, the idea that if two objects of perception have a logical relation between them – contrariety, say – then the ‘movements’ that represent them, their codified representations,33 will have the same logical relation between them. No doubt it is a natural enough assumption, but the interesting thing is that Aristotle acknowledges it explicitly. But if we were to deny it, then the problem of the copresence in sense of contrary movements would not arise.

2.4 Taking Aristotle Seriously I think that we should take Aristotle more seriously and try harder to get our heads into what he was trying to do with the analogy of the point or limit. And to do so requires, I believe, that we start with a little bit of unthinking: we have to unthink some of our ready understanding of geometry. We have a concept of what is often called Cartesian space: the world is an infinite three-dimensional spatial manifold in which objects play out their careers. We can give the spatial coordinates of any object at any time, relative to some arbitrarily chosen origin. The world is dense with points, with lines, with planes: they are, literally, everywhere, even though we may happen to name or consider only a small

31 Ross’ translation, with modification. It is true that Aristotle does not here mention judging or distinguishing (krinein), but equally it is true that no important structural distinction is ever made among perceiving, judging, asserting, knowing. . . . 32 Tr. J. I. Beare, in The Complete Works of Aristotle, 2 vols., ed. Jonathan Barnes, Princeton, 1985. 33 There has been a good deal of debate here about whether Aristotle was what we might call a ‘realist’ in cognition – that is, did he think that forms were imprinted tels quels on the cognizer? Does the eye which sees yellow become yellow; does the common organ of sense become yellow? Does the tongue which perceives bitterness become bitter; does the common organ of sense become bitter? Or does Aristotle hold a subtler theory according to which these various forms are imprinted on the cognizer in encoded form? Different texts pull opposite ways on this question. But here, in the three passages we have been considering, Aristotle seems to hold to the subtler theory, and speaks of ‘movements’ (kinêseis) representing, or corresponding to, the perceived objects. This same issue is the focus of a disagreement between Leibniz and Malebranche; see Jean-Pierre Schacter’s chapter in this volume.

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number of them. There is a point with coordinates (x,y,z) relative to the summit point of Mt Everest; that point is defined by those coordinates. That it happens to be the point at the apex of the Eiffel Tower is interesting, but not part of the definition of the point. Aristotle, I think, saw things exactly the opposite way. For him the definition of the point in question would have been that it was the apex point of the Eiffel Tower; it would have been a relatively uninteresting fact that it was a certain distance, in three dimensions, from the top of a high mountain in Asia. Again, a line exists by being drawn on a board. A line AB is of definite length, and although you can extend it in either direction, if you don’t do so, then it is simply line AB, period. A is its start point and B is its end point, or vice-versa. It does not exist before A, and it does not exist beyond B – not unless you draw it. The essence of a mathematical object, whether point or line or plane or solid, was given by the material object to which it belonged. Let me now offer four pieces of evidence for this interesting difference between Aristotle’s geometrical understanding and ours. The first three are well-known Aristotelian doctrines that need no elaboration; the fourth is a curiosity that sheds interesting light on this matter. (a) For Aristotle, no line can be extended indefinitely, because eventually it will hit the outer boundary of the world, and the world is finite. There is no infinite absolute space. (b) Though this is notoriously difficult for us, Aristotle famously understands place as relative to things. There is no absolute space. (c) Mathematical objects, for Aristotle, are real objects, with their uninteresting or irrelevant attributes eliminated in thought – abstracted. (d) There is an intriguing passage at the end of the little treatise de Lineis insecabilibus (972b 25ff.) in which we learn that if the end point of one line coincides with that of another we have not a point but a joint: the points, it seems, though coincident, remain two points.34 Although this treatise is not thought to be by Aristotle, it is of the time and place – perhaps by Theophrastus or Strato – and it shows us the ideas and issues that were in the air. A point, then, is not defined by its position in absolute space, as the Cartesian view would have it; rather a point is defined by its position in some or other named object or line. The westernmost point of Europe or the southernmost point of Chalcidikê is precisely that; that is its definition. Its definition places it relative to an actual object. The starting point of the line AB that I have drawn on the board is precisely that: its essence, if you like, is that it is the starting point of AB. And AB is the line that I have drawn on the schoolroom board, in chalk, in the town of Stagira, in 350 BCE.

34 I am grateful to my former student Sammy Jakubowicz for his perceptive analysis of this passage in his thesis The Trouble with Touching.

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Now the burden of all this is that when a given point is both the starting point of BC and the ending point of AB, we have a spatial coincidence of essences: we have two logical subjects35 in one place. To use scholastic language, we have two essences in one existence. We have a thing that is one in number and in place, but two in being or essence. This conception is what explains Aristotle’s language about difference in being or definition: the language is not grandiose at all; it is exactly right. So the analogy of the point or limit is meant to introduce the idea of the spatial coincidence of two logical subjects, two essences, two subjects of predication. But how is that meant to solve the problem how there can be two contrary properties belonging to one thing? Presumably it could work in this way: one property belongs to one being, one logical subject, and its contrary belongs to the other being, the other logical subject, and the two beings coincide in place. Can this be? For sure, it is a fascinating notion, an intriguing foray into the outskirts of paraconsistent logic, the branch of logic that explores truth relations when the Principle of Non-Contradiction is suspended. We can begin by thinking about the mathematical case. Let us consider the point B that lies in the line AC. B is a single point, but it is two in ‘being’: it is the end point of line AB, and the beginning point of line BC.36 That would illustrate the general idea that a single thing may be plural in ‘being’, but it doesn’t yet get us close to a violation, or apparent violation, of the Principle of Non-Contradiction. Does this analogy help with Aristotle’s problem of understanding how a single thing can have two contradictory ‘beings’ – how the cognizer could be both black and white, or receive the forms of both black and white at the same time? It might if we press the analogy a little. Imagine two mathematical circles that are tangent to one another: they share one and only one point. Imagine further that one of the circles is black, the other white.37 What then is the color of the point of tangency? Clearly there is no reason to say that it is white rather than black, or black rather than white. Is it both white and black, thus apparently violating PNC? Or is it neither black nor white, thus apparently violating the Law of Excluded Middle?38

35

The phrase ‘logical subject’ is, doubtless, anachronistic when it is suggested as an interpretation of Aristotle’s thought. But it does capture, in modern idiom, the gist of the idea that he seems to be pursuing. 36 Alexander (96, 14) suggested that the idea here was the point that was centre of a circle, and, as such, the terminus of all the radii of the circle, and Themistius (159, 10), Philoponus (481, 8), Sophonias (114, 25) and others followed him in this. This image has the advantage of suggesting the centre of the circle as the analog of the faculty of common sense, on which all the data of the special senses converge. Simplicius, however, saw that the text need not be read so elaborately: a point in a line will give all that Aristotle needs (201, 5). Charles Kahn offers a similar interpretation of the analogy of the point in ‘Sensation and Consciousness in Aristotle’s Psychology’, Archiv für Geschichte der Philosophie, 1966, 55–59. 37 Admittedly, mathematical circles are not normally thought of as having color. But mathematical circles are created by abstracting undesired features from real circles, and we could simply fail to abstract the color of the circles, and so end up with one colored and one white mathematical circle. 38 We would have to set some constraints on the universe of discourse to get a violation of LEM, of course.

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Aristotle’s choice, it seems, would be that the point is both black and white, black in so far as it belongs to the black circle, and white in so far as it belongs to the white circle. Black belongs to one logical subject, and white belongs to the other logical subject, and the two logical subjects happen to coincide. We have the illusion of a violation of PNC, but it is only an illusion: the two contrary properties actually belong to two distinct beings, though those beings are coincident in place. There may be too many incidental problems with this analogy;39 let me offer another. Cleanthes and Milo each have a farm, and the southern boundary of Cleanthes’ is coincident with the northern boundary of Milo’s. Draw a line AC from the front door of Cleanthes’ house to the front door of Milo’s house. There is a point on this line, call it B, that is on the boundary between the farms. Is B on Cleanthes’ farm or on Milo’s? No doubt it could be on both, without contradiction. Let us then further assume that Cleanthes has been a worthy citizen and the temple priest has blessed him and his land; Milo has been a blackguard and the priest has cursed him and his land. What is the status, then, of point B? Is it blessed or cursed? The point B has two ‘beings’, two definitions. Along the line AC, it is the last point on Cleanthes’ farm, and it is also the first point on Milo’s farm. In its ‘being’ as the last point on Cleanthes’ farm it is blessed; it its ‘being’ as the first point on Milo’s farm it is cursed. So one and the same point admits of contrary properties, but only because there are two logical subjects resident in that point. So, the argument runs, just as a single point can be two in its ‘being’ – can even admit contrary predicates, one under each ‘being’ –, in the same way the cognizer, while numerically one, can be two in its ‘being’, and can even admit contrary predicates, one under each ‘being’. This seems very elegant. But will it work in the case of cognition? It is, I believe, the outline solution that Aristotle has thrown us; can we fill in the details? Let us take the problem cases in turn.

2.4.1 Heterogeneous Attributes: White and Sweet Certainly it provides a tidy way of solving the easier problem, namely, how one and the same cognizer can be simultaneously aware of the data of different senses, the heterogeneous attributes. The common sense is a coincidence of the special senses. In so far as the common sense is the sense of sight, it receives the form white; in so far as the common sense is the sense of taste, it receives the form sweet. So sweet and white can both belong to common sense, each of these properties belonging to it under one of its ‘beings’. But this is the easy problem, and we had already found a solution for it in any case.

39 For example, is there any meaning in saying that a point is colored? Or indeed, are points perceptible at all?

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2.4.2 Homogeneous Contraries: Black and White What about the harder problem, that of the homogeneous contraries? How can we account for the simultaneous perception of black and white, of sweet and bitter? Here, I think, we would have to say something like the following. There are two distinct beings or logical subjects coincident in the common sense (along with many others of course): a black-cognizer and a white-cognizer. The black cognizer can be actualized, and the white cognizer can be actualized, and because these cognizers are coincident in space we have the illusion of a violation of PNC. But the violation is only an illusion: the contrary properties actually belong to two distinct logical subjects. But this seems to run counter to the whole spirit of Aristotle’s theory of perception: it is one sense that perceives the whole range of properties running between the poles of a pair of contraries – black and white and all the colors between, sweet and bitter and all the flavors between. To invent different logical subjects as the perceiver of each possible color or flavor seems quite against the whole tenor of Aristotle’s theory. It looks as though the outline solution that Aristotle has thrown us cannot be used, at least not for the hard case of homogeneous contraries. There is however another device in Aristotle’s toolbox for creating logical subjects. It is the device of qualification, represented by that ubiquitous but too-little considered word qua.40 ‘Coriscus qua veiled man’ is a different logical subject from ‘Coriscus qua my old friend’. Unless we allow the force of qua we will end up with a paradox of the following sort: I don’t know the veiled man; the veiled man is Coriscus; Coriscus is my old friend; therefore I don’t know my old friend. Or, more strikingly, and more to our purpose here, we could conclude: Coriscus both is and is not known to me. Let us then consider Aristotle’s example of simultaneous awareness of black and white, and, to simplify matters, let us imagine that the entire left side of our visual field is filled with black, and the entire right side filled with white. We can easily then construct two logical subjects as follows: ‘qua representation of the left side of my visual field, my common sense (organ) is moved by the stimulus black’ and ‘qua representation of the right side of my visual field, my common sense (organ) is moved by the stimulus white’. And then we would have what we need: two contrary movements belonging each to a different logical subject, with those two logical subjects being coincident. That seems to do the trick for the case of awareness of black and white. By being divided into two different logical subjects, by the device of qualification, the (organ of) common sense admits of contrary properties.

40

I am grateful to my former student Dwayne Raymond, whose doctoral thesis ‘Qua’ argues the centrality of the notion of qualification – the centrality of qua – in Aristotle’s logic and metaphysics.

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2.4.3 Homogeneous Contraries: Sweet and Bitter Matters are altogether more difficult, though, with Aristotle’s other example of homogeneous contraries, the sweet and the bitter. It is a curious fact that none of the commentators, I believe, has thought at all carefully about this example. The problem is that a thing can be both bitter and sweet at the same time, without any spatial separation between bitter and sweet regions: a gherkin is not bitter at one end and sweet at the other, but bittersweet throughout. Nor was the sophistication of the agrodolce unknown in Aristotle’s time: oxymel, a mixture of honey and vinegar, was a standard part of the pharmacopeia, and, it seems, of the kitchen as well.41 Moreover, the category of the bittersweet, the glukupikros, was of huge cultural importance, especially in its figurative sense.42 How, then, can we construct a logical subject that will allow us to separate the sweet and the bitter in sense in such a case? Perhaps we needn’t bother. For it would seem, once we reflect on this case, that what it really shows is that, despite our ready notions about the matter, bitter and sweet are not actually contraries. If, indeed, they can both characterize one and the same object at the same time, without spatial partition – a swig of oxymel, for example – it would seem that they are not contraries after all. This is not a problem that we should try to solve.

2.5 Conclusion These troubled Aristotelian texts about the unity of consciousness have seemed to generations of commentators to be very unsatisfactory, and to contain an unresolved contradiction at their core. We have described three ways in which commentators have tried to dodge this trouble, and a further way in which a commentator might try to dodge it, and we have seen that these avoidance devices are not true to Aristotle’s enterprise, whether its general character or its explicit hypotheses. We have then tried to probe deeply into the meaning of his analogy of the mathematical point or limit, and discovered that what he was probably canvassing there was the idea of a coincidence in space of two or more different logical subjects. Initially this idea seemed unhelpful for explaining the simultaneous perception of contraries, but when we further considered Aristotle’s apparatus of qualification – represented by the word qua – we saw that there was indeed a way to make the black and the white that one perceives the attributes of different logical subjects. Finally we considered the other standard example of contrary perceptible objects, the bitter and the sweet, and concluded that there is something wrong with the example. Whatever the difficulties and the obscurities of the ingenious theory for which Aristotle is reaching in these texts, one thing is clear: he cannot subscribe to the Achilles argument. He cannot subscribe to it because he thinks that the phenomenon 41 42

There is a discussion of oxymel in the pseudo-Aristotelian treatise Problemata, 19, 43. Most famous, perhaps, is Sappho’s description of love as bittersweet.

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of perceiving of disparate objects does not simply require that the cognizer be one – partless, simple, atomic –; on the contrary, it requires that the cognizer be both one and multiple, one in one way and multiple in another, undivided in number but divided in being. Aristotle’s scientific work on cognition takes him to a view remote from the pure, simple, partlessness of mind envisioned by the Achilles argument.

Chapter 3

The Neoplatonic Achilles Devin Henry

At first it appeared to me that the Neoplatonists recognized at least the broad Achilles and that Plotinus had articulated the first narrow version of the argument.1 Upon reflection I became increasingly skeptical of this assumption. Based on other contributions to this volume, it seemed wrong to say that what the Neoplatonists articulated was an Achilles argument at all. And yet their influence on the development of the Achilles remains undeniable. (Moreover, that influence seems to be more direct than that of the Ancient Philosophers.) I now believe that what we find in Neoplatonism is in fact a set of related arguments that I shall collectively refer to as a ‘proto-Achilles.’ At the heart of all this is an attempt to defend the immortality of the soul against two rival camps. On the one hand, the Stoics and Epicureans argued that the soul is body of some kind and that it is destroyed by being decomposed into its constituent elements. On the other hand, the Aristotelians held that the soul is not itself a body but the form or actuality of a (living) body. As such, it not capable of existing apart from that body. On this theory the soul is destroyed by being separated from its bodily substrate, which happens at death.2 The Neoplatonists reject both these conceptions of soul. The soul is neither a body nor an inseparable entelechy. It follows from this that the soul is indestructible and therefore immortal:

D. Henry Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 85876, Fax: (519) 661-3922 e-mail: [email protected] 1 The introduction to this volume has identified a ‘broad’ and ‘narrow’ version of the Achilles argument in the history of philosophy. 2 This view also reflects the Pythagorean view that the soul is the harmony of the body, like the harmony in the well-tuned lyre. In that case one might argue that the soul is destroyed when the animal body is destroyed just as the harmony is destroyed along with the lyre (cf. Phaedo 85E–88D).

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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(1) There are two ways for a thing to be destroyed. (a) If it is a body,3 it can be destroyed by being decomposed into its constituent elements. (b) If it is the sort of thing that can only exist in a substrate—if it is inseparable from body—it can be destroyed by being severed from its substrate. (2) The soul is incorporeal (asomaton) and not a body.4 (3) The soul is separable from body.5 (4) Therefore, the soul is indestructible. (From 1a and 2, and 1b and 3) In this chapter I shall focus on the various ways the Neoplatonists articulated this basic argument. Although none of these properly constitute an Achilles argument (except when ripped from its context in this broader argument), it is possible to identify key elements of later formulations in their discussions. It is in this sense that I believe the Neoplatonists offer us a proto-Achilles. The historical development of the Neoplatonic argument is full of twists and turns. Plotinus (206–260 CE) first formulates the immortality argument at Enneads IV.7.12.6 Porphyry (232–309 CE), a student of Plotinus’s, later modifies the argument by deriving the separability of the soul from its capacity for self-reversion (Sentences 41).7 Proclus (411–485 CE) inherits this version of the separability argument from Porphyry but adds a new argument for the incorporeality of the soul based on the same principle of self-reversion. Proclus’s main contribution, however, was to fortify the argument by presenting it in the form of a logical proof. As we shall see, the immortality of the soul is presented as an a priori deduction from a series of propositions established at various points throughout the Elements.8 The argument shows up again in the 6th Century CE in Philoponus, who offers his own version that 3 What I am calling ‘body’ and ‘corporeal’ translate the Greek soma and somatos, respectively. The Neoplatonists take ‘body’ to be a substance that is divisible into spatially distinct parts. Every soma is thus essentially composite (suntheton) and resolvable into its constituents elements. (See e.g., Plotinus Enneads IV.7.1–2; on the corruptibility of body see Enneads IV.1.1,12–17; IV.7.1,18–20.) The choice of terminology here is important. For example, Mijuskovic claims that Plotinus attempts to show that the soul is an ‘immaterial’ unity. However, being incorporeal (asomaton) is not equivalent to being immaterial for the Neoplatonists. For they held that matter as such is incorporeal (Enneads II.4.8–12). 4 This premise is the conclusion of what I shall refer to as ‘the incorporeality argument.’ The Neoplatonists offer different versions of this argument, different ways of proving that the soul is incorporeal and thus not liable to decomposition. 5 This is the conclusion of ‘the separability argument.’ Again, this argument takes different forms. 6 Plotinus was the founder of Neoplatonism. 7 On the concept of ‘self-reversion’ see below. In the context of the soul, self-reversion takes the form of self-reflection. 8 Proclus’s Elements of Theology (‘theology’ in the Aristotelian sense of first-philosophy or metaphysics), in which his version of the Achilles appears, employs ‘the method of a priori deduction known to the ancient mathematicians as synthesis and familiar to us from Euclid and Spinoza’ (Dodds 1963, xi).

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combines Plotinus’s appeal to unity for deriving the incorporeality of the soul with Proclus’s appeal to self-reversion for deriving its separability.9 Finally, Simplicius, also writing in the 6th Century, extends the separability argument to include the sensory soul,10 something explicitly rejected by Porphyry and Philoponus. Within this complicated history it is possible to identify two main formulations of the immortality argument: a Plotinean version and a Proclean version. In what follows I shall concentrate on these two formulations. The major difference between them lies in the way each secures the incorporeality of the soul (premise (2)). Plotinus moves from the unity of consciousness to the incorporeality of the soul to its immortality, while the Proclean version moves from the capacity of the soul to reflect on itself to its incorporeality to its immortality.11

3.1 The Plotinean Version The argument for the immortality of the soul first appears in Plotinus at Enneads IV.7.12: [1] Again, everything which is dissoluble is a compound (sunthesis) and, insofar as it is compounded, is naturally liable to be disintegrated in the same manner. But the soul is a single and simple nature, being actuality in the sphere of life. Therefore, it is not capable of being destroyed. [2] ‘But if it is divided into parts, it could be dissolved by being chopped up into pieces (kermatizomenê).’ But the soul is neither a mass (ongkos) of some sort nor a quantity, as has been demonstrated. [3] ‘But it will come to destruction by qualitative change (alloiôtheisa).’ But qualitative change that destroys separates the form and leaves the matter. But this is an affection that happens to a compound. If, then, the soul can be destroyed in neither of these ways, it must of necessity be indestructible.12

We can divide this passage into three parts (indicated by my numeric insertions). In the first part Plotinus argues for the indestructibility of the soul on the grounds of its simplicity. Since the soul is not a composite substance, it is not liable to de-composition. The second and third parts raise objections to this, targeting the different ways the soul might be considered ‘composite’. The first objection is based

9

Philoponus in DA 464,24–466,28. Although there is some dispute concerning the authorship of the De anima commentary attributed to Philoponus, I shall take this as authentic. For a defense of this see Wolfgang Bernard, ‘Philoponus on self-awareness,’ in Philoponus and the Rejection of Aristotelian Science, ed. Richard Sorabji (London & Ithaca, NY: Duckworth & Cornell University Press, 1987), 154–5. 10 Simplicius in DA 173,3–7; 187,27ff. The authorship of the De anima commentary attributed to Simplicius is also disputed, though again I shall take it as authentic. 11 It remains unclear to me the extent to which the two agree on the move from separability to immortality. They certainly appeal to different arguments here (as we shall see). 12 All translations are my own unless otherwise indicated. (The Plotinus translations are based on A. H. Armstrong, Plotinus: Enneads. Loeb Classics, vols. I–VI (Cambridge: Harvard University Press, 1967)). I am grateful to Karen Nielsen for her help with some of the difficult Greek passages.

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on the idea that the soul is a material compound (a body composed of elements).13 The second imagines the soul to be a hylomorphic compound (a composite of matter and form).14 The former objection arises because Plotinus accepts that the soul is, in some sense, divisible into parts (IV.1.1). And if it has parts, one might argue, then surely it can be divided into them. However, Plotinus holds that the soul is not divisible in the way bodies are (it cannot be chopped up into pieces) since it is incorporeal.15 On the other hand, if the soul were a hylomorphic compound, then it might be destroyed through alteration, which separates the form from its material substrate. However, Plotinus has already offered arguments to show that the soul is not a composite in this sense, either (IV.7.8). In what follows I shall focus on Plotinus’s arguments for denying the soul is a material composite (soma), since historically these constitute the more influential portion of Neoplatonism on the development of the Achilles argument.

3.1.1 The Unity of Consciousness In Enneads IV.7.6 Plotinus argues that perception would be impossible if the soul were a body (soma).16 It will be useful to quote the entire argument so that we have the relevant text in front of us: If something is going to perceive anything, it must itself be one and must apprehend it by the same [sense], both if several impressions are [perceived] through many sense organs, or many qualities [are perceived] in one object, or if one sense organ [perceives] a complex object, for example, a face. For there isn’t one [perception] of the nose and another of the eyes, but one identical [perception] of all of them together. And if one [sense-object] enters through the eyes, and another through the hearing organ, there must be some one place to which they both go. Otherwise, how could we state that they are different from each other, if the sense-objects did not all come together to one and the same place? Therefore, this place must be like a center point, and the perceptions coming from all places, like the lines coming from the circumference of the circle, must terminate there. And the thing that apprehends these perceptions must be of this sort, really one. But if this should become extended and the incoming perceptions were to strike against, as it were, both ends of a line, then either they will meet together again at one and the same point (e.g. the midpoint), or one will strike at one point and another at another point and they will each have a perception of different things, just as if I perceived one thing and you another. And if the sense-object is a single thing, for example a face, then either it will be united together into one thing (which is what clearly does happen, for it is united together in the pupils) or how could the largest things be

13 Cf. Enneads IV.7.1,18–20: ‘And besides this, since they [material composites] have magnitude, because they are bodies, they can be divided and broken up into small pieces and so undergo destruction in this way.’ 14 Cf. Enneads IV.7.1,15–18: ‘And even if one part is isolated when it has become one, it is not truly [one], since it admits of dissolution into form and matter, from which it is necessary that even the elementary bodies should have their composition.’ 15 For more on this see ‘The Simplicity of the Soul’ further below. 16 Plotinus identifies several other phenomena that would be impossible if the soul were a body. Below I discuss his claim that thought would be impossible.

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seen through the pupil of our eye? So still more when they [sc. the sense-objects] reach the ruling principle,17 they will become like partless thoughts, and this [ruling principle] will be without parts. Or, if this [sc. the ruling principle] is a magnitude, it [sc. the sense-object] would be divided up with it, so that each part [of the ruling principle] would perceive a different part of the sense-object and none of us would ever have a grasp of the object as a whole. But the whole thing is one; for how would it be divided? For equal will certainly not match up with equal because the ruling principle is not equal to every sense-object. Into how many parts, then, will the division be? Will it be divided into a number of parts corresponding to the number of variegated qualities the incoming sense-object has? Are we to suppose, then, that each of these parts of the soul will then perceive each [part of the sense-object] with its own parts? Or will the parts of the parts lack perceptions? But that is impossible. Yet if any and every part [of a corporeal soul] perceives the whole [sense-object], then since the dividing of a magnitude is naturally carried down to an infinite number of parts, the perceptions of a particular sense-object will also become infinite for each part, yielding an infinite number of images (eikonas) of the same thing in our ruling principle.

Plotinus considers two features of our psychology that appear puzzling on the view that the soul is a body. One is the way the unity of consciousness arises from the multiplicity of perception. When we perceive the outside world, different sensory properties are received through different channels: color through the eyes, sound through the ears, and so forth. Yet, our experience of them is not fragmented but integrated and unified. When we perceive a face, for example, there isn’t one perception of the nose and another of the eyes, but one identical perception of all of them together. Plotinus argues that this would be possible only if the senses all reported to a single, unified perceiver that transforms their different inputs into a single, unified experience. The other puzzling feature is our ability to make comparative judgments about disparate sense-objects (‘. . .how could we state that they are different from each other . . .’). This cannot be accomplished by any of the five senses, Plotinus argues, since each sense can only make judgments within its own modality. Sight says ‘This is white!’, and taste says ‘This is sweet!’; but what compares the two and asserts that white is different from sweet? Again Plotinus argues that this ability can only be explained by positing a single, unified perceiver beyond the five bodily senses.18

17

Enneads VI.7.6 concern what Plotinus calls ‘the ruling principle’ (to hêgemonoun), which is the ultimate subject of conscious experience. This part of the soul would correspond to what the Aristotelians call the common sense. In what follows I shall refer to this as ‘the central consciousness.’ 18 As Nielsen has shown (Chapter 1 above), this worry has its roots in Plato’s Theaetetus. At 184CD Socrates remarks that it would be ‘very strange indeed’ if the different senses did not all report to a single principle (if we were all like wooden horses with several perceivers situated inside, each perceiving its own distinct object). However, what drives the main argument of that passage is not the unity of consciousness per se but the soul’s ability to make judgments about different sense-objects, to ‘examine their being in comparison with one another.’ This same argument is deployed again by Aristotle in DA III.2 (see Chapter 2 of this volume). According to Aristotle, it would be impossible to make comparative judgments unless the different sense-objects were ‘clearly apparent to one thing,’ so that what asserts their difference must be a unity (426b8–22). However, unlike Plato, Aristotle does not draw the further conclusions that (a) this principle of soul

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The incorporeality of the central consciousness follows directly from its essential unity. For only an incorporeal substance, Plotinus contends, possesses the kind of unity necessary to explain our experience. In order to account for experience, the data from the five senses must all converge on a single perceiver. Now suppose this central consciousness was a body and that it was divided up into parts corresponding to the parts of its sense object.19 How could it perceive the whole object? Plotinus considers three alternatives. First, the whole consciousness might perceive the whole object in virtue of each of its parts perceiving a separate part. However, unless all of these sub-perceptions came together before another percipient, our experience would be fragmented into isolated perceptions ‘and it would be as if I perceived one thing and you another’ (cf. Aristotle DA III.2, 426b15–20). The second option Plotinus considers is that the central consciousness perceives the whole object even though none of its parts perceives anything. But this is impossible. For how can the whole consciousness perceive the object if none of its parts do? Finally, each part of the central consciousness might perceive the object as a whole. However, in that case there would be a multitude of perceptions of the same thing in our consciousness, which contradicts experience.20 Plotinus thinks that no account of a corporeal soul could avoid this trilemma. If the soul is going to perceive anything, he argues, it must be a unity and therefore cannot be a body of any kind. For a body, being composed of spatially distinct parts, could never apprehend the manifold of perception in such a way that its act constituted a single, unified grasp of that manifold as a whole.21 Enneads IV.7.8 deploys two further arguments to show that the intellect cannot be a body of any kind, either.22 The first argument begins from the claim that thinking must be an apprehension of an object without the use of the body, since otherwise it would be identical to sense-perception, which involves grasping an object by means of a bodily organ. But if thinking is an activity that occurs without the body, then it

cannot be a body and (b) its grasp of their difference cannot be a perception. Plotinus too seems to reject (b). 19 Plotinus claims that the object that this perceiver ultimately perceives must itself be unified and become like a ‘partless thought.’ However, for the sake of argument he allows that the sense-object is a body divisible into spatially distinct parts. 20 Plotinus’s argument against the third option actually appeals to the infinite divisibility of matter: ‘Yet if any and every part [of a corporeal soul] perceives the whole [sense-object], then since the dividing of a magnitude is naturally carried down to an infinite number of parts, the perceptions of a particular sense-object will also become infinite for each part, yielding an infinite number of images of the same thing in our ruling principle.’ The Atomists would simply deny the premise of infinite divisibility, since they posit atomic (literally ‘uncuttable’) bodies. However, this would not avoid the problem Plotinus identifies with the third option. For if the soul is composed of atomic particles, and each of those particles perceived the sense-object as a whole, then there would still be multiple (albeit unified) perceptions of the same thing in our consciousness. 21 As we shall see, Plotinus does accept that bodies can be ‘one’, but only in a very weak sense: they are one by continuity. I shall return to this shortly. 22 See also Enneads IV.4.11, 12–17. This passage is discussed in Emilsson, Eyjólfur Kjalar, Plotinus on Intellect. (Oxford: Clarendon Press, 2007), 196–7.

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is all the more necessary that the thing that thinks has existence apart from body and so cannot itself be a body.23 The second argument is much simpler. Since the objects of thought are without magnitude (e.g. the circle itself), the intellect which thinks them cannot be corporeal. For if it were a body, it would be a magnitude divisible into parts. And how can a magnitude think that which is not a magnitude and what has parts that which has no parts?24 Enneads IV.7.6 and IV.7.8 both provide the means for securing the move from incorporeality to immortality. Since the soul (both its sensory and intellectual aspects) is incorporeal, it is not liable to disintegration. For what is incorporeal is simple and without parts.25 As other chapters in this volume show, the unity argument deployed by Plotinus in Enneads IV.7.6 proved to be especially influential in the history of philosophy. Indeed, it was this sort of argument that Kant described as ‘the Achilles of all dialectical inferences in the pure doctrine of the soul’ in the Second Paralogism of the Critique of Pure Reason. However, other contributions to this volume also show the influence of Proclus on the development of the (broader) Achilles. Before turning to the Proclus, however, I want to revisit the first objection Plotinus considers against the immortality of the soul and elaborate on the sense in which it is ‘a single and simple nature’.26

3.1.2 The Simplicity of the Soul Enneads IV.7.12 argues from the simplicity of the soul to the conclusion that it is not liable to decomposition and thus cannot be destroyed in the manner of corporeal substances. ‘But if it is divided into parts,’ the opponent objects, ‘it could be dissolved by being chopped up into pieces.’ This objection arises because Plotinus accepts that the soul is both one and divisible into parts. And if it is divisible into parts, then surely it can be destroyed. However, Enneads IV.1.1–2 has already shown that the unity and divisibility of the soul are different from that exhibited by bodies: The soul is not one in the sense in which a body is one. For a body is one by continuity, but its parts are different from each other and in different places. And it is not one in the way in which a quality is one, either. But the nature, at the same time divisible and indivisible, 23 This principle (whatever has a separate activity must itself have separate existence) is later formalized in Proclus ET 44 (cf. 83). According to Proclus, it would be absurd to suppose that an activity which does not require a bodily instrument proceeds from a substance that cannot exist without the body. Both Plotinus and Proclus use this principle to establish the soul’s separability, though in different ways. 24 The argument is Aristotelian in origin (DA I.3, 407a18–19): ‘Again, how can it think (a) that which has parts with that which has not or (b) that which has no parts with that which has parts?’ Ironically, Plotinus seem to have missed the fact that this is directed against the Timaeus conception of soul. 25 This follows from the Neoplatonic conception of ‘body’. See note 3 above. 26 This appears to have the structure of a ‘narrow Achilles’ argument even according to the strict standards of the introduction to the present volume. However, calling it such would wrench it from its context as a step in the argument for the immortality of the soul. It is, perhaps, a ‘broad Achilles.’

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D. Henry which we affirm soul to be, is not one in the way in which an extended thing is one, having [spatially] distinct parts, but in another way: it is divisible, because it is present in every part of that in which it exists, and indivisible, because it is present in all the parts as a whole and in any one part of it as a whole. . . .Having no magnitude, it is compresent (sunesti) with every magnitude and is here and again there, yet not with a different part but with the same part. So that it is both divided and yet not divided, or rather, it is not itself divided and has not become divided. For it remains whole with itself, but it is divided in the realm of bodies in virtue of the characteristic divisibility of bodies, since they are incapable of receiving it indivisibly. Thus, divisibility is an affection of bodies, not of [the soul] itself. (Enneads IV.1.1,60–77)

Plotinus takes the soul to be a unity, but not in the way that bodies are unities. Bodies have what we might call corporeal unity. They are (on the Neoplatonic conception of body) composed of spatially distinct parts that are one by virtue of continuity. This makes them liable to decomposition: they are the sorts of unities that can be divided by being chopped up into pieces, which interrupts their continuity. At the other extreme are pure unities. Plotinus characterizes pure unity as being one in the sense of being ‘completely indivisible and a self-contained one, a nature altogether acquitted of multiplicity and divisibility.’27 Only the One possesses this pure and perfect unity. Enneads IV.1.2 presents a series of arguments to show that the soul is neither a corporeal unity (altogether divisible) nor a pure unity (altogether indivisible). The arguments against taking the soul to be a corporeal unity closely resemble those in IV.7.6 (e.g. ‘How will it know as one the contents of many perceptions, of eyes and ears for instance?’). The argument against taking the soul to be a pure unity is that, if it were, the soul ‘would set itself, so to speak, at the centre of each living being and leave the whole mass of it soulless.’ Although the soul is not itself a body, it penetrates all the parts of the body, and so in that sense (but only that sense) it is divisible. The unity of the soul thus lies somewhere between corporeal unity and pure unity. It has what we might call incorporeal unity: it is at once both divisible and indivisible.28 This answers the objection to the immortality argument. The soul is not one by continuity, since it is not a body composed of spatially distinct parts. Therefore, it is not divisible in the way that bodies are divisible (it cannot be chopped up into pieces). Rather, it is divisible only per accidens because it is present in every part of the body, which is itself per se divisible.29 Yet, it remains indivisible because it is present in every part of the body as a whole.30 27 Enneads IV.1.2, 36–7: ameriston pantê kai eph’ heautou hen, kai pantê plêthous kai merismou ekpheugoi phusin. Cf. Plato Sophist 245A8: ‘Surely a thing that’s truly one, properly speaking, has to be completely without parts.’ 28 Enneads IV.1.2, 54–5: ‘The forms in body [sc. souls] are many and one; bodies are many only; the Supreme one only.’ 29 At the end of the above passage Plotinus insists that divisibility is not an affection of the soul per se but only of the body in which it exists. Thus, Plotinus goes on to say (IV.1.2,14–16), to describe the primary ruling principle as a part of the soul is to speak ‘uncritically’ (anexetastôs). 30 There are traces of this idea in Aristotle. Aristotle accepts that the soul has parts, but not in the

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3.2 The Proclean Argument In contrast to Plotinus, the starting-point of Proclus’s argument is the idea of self-reversion. Reversion is a technical concept in Neoplatonism taken over from the Stoics (see, e.g., Epictetus Diss. III.22.38–9). The Greek word epistrophein literally means ‘to turn towards’ and the phrase to pros heauto epistrophein ‘to turn towards itself.’ What is important about the process of reversion, for our purposes, is that it involves a union of sorts whereby that which reverts becomes conjoined (sunaptein: ET 32) with that upon which it reverts, resulting in the two becoming one.31 According to Philoponus in DA 466,27–8, a thing’s reverting on itself ‘is nothing other than laying a hold of its own activities.’ In the case of the intellect, this takes the form of self-knowledge or self-awareness, a reflexive act in which the intellect gains direct access to itself as a whole (Proclus in Tim. 2,286,32): ‘Hence, it is immediately evident that reverting upon itself is knowledge of itself, and of everything in, prior to, and proceeding from itself. For all knowledge is a reversion to the object of knowledge, and an alliance and adaption to it.’ For Proclus, the soul’s unique capacity for self-reversion is the key to its immortality.32 In ET 187 Proclus supplies a proof for the immortality of the soul that draws directly on the argument from Plotinus: Proposition 187: Every soul is indestructible and imperishable. Anything that can in any way be dissolved or destroyed either is corporeal and composite or has its existence in a substrate. The former kind of thing, being made up of a plurality of elements, is destroyed by being dissolved, while the latter kind, being capable of existence only in something other than itself, disappears into non-existence when severed from its substrate. But the soul is both incorporeal and external to any substrate, existing as it does in itself and reverting on itself. It is, therefore, indestructible and imperishable. (Translated after Dodds)

Propositions 15 and 16 prepare the way for this argument by laying the groundwork for its two main premises: the soul is incorporeal (ET 15) and separable in being (ET 16). As we shall see, both of these attributes are shown to follow directly from the soul’s capacity for self-reversion.

sense that you could cut it into pieces. This is shown in the case of things like worms. If you cut the worm’s body into two, it isn’t the case that its sensory capacities go with one part and the nutritive capacities with the other. Rather what happens is that the entire soul goes with each part, which shows that the soul is present everywhere in the body as a whole. See DA II.2, 413b12–25. 31 More generally, the process of reversion involves the reconnecting of what is at a lower level with what is at a higher level (John Dillon and Lloyd P. Gerson, Neoplatonic Philosophy: Introductory Readings [Indianapolis: Hackett Publishing Company, Inc., 2004], 365). However, it is the uniting of the two elements that is central to Proclus’s argument. 32 Dodds translates epistrophê pros heauto as ‘introversion’, which may be more appropriate here. For most Neoplatonists self-reversion (or introversion) is unique to the intellect. As Aristotle is supposed to have shown in DA III.2, the ordinary sense faculties are incapable of directing their activities on themselves since they ‘have acquired their efficiency through the medium of the body’ (Porphyry Sentences 41). Proclus speaks of ‘the soul’ reverting on itself, though Dillon and Gerson take him to mean the cognitive soul (278 n. 48). I am not concerned with the distinction between soul and intellect here and will use the two quite interchangeably.

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3.2.1 Incorporeality The Stoics held that the soul is both corporeal and capable of self-reflection. Proclus insists that these two properties are incompatible: if the soul is corporeal, it is not capable of self-reversion; if it is capable of self-reversion, it cannot be corporeal.33 The proof of this is demonstrated in ET 15: For nothing bodily is of such a nature as to revert upon itself. For if that which reverts upon anything is conjoined with that upon which it reverts, then it is obvious that all the parts of the body that reverted upon itself must be conjoined with every other part. For that is what it is to revert upon itself: both elements become one, both the reverted subject and that on which it has reverted. But this is impossible for a body and all divisible substances in general. For the whole of a divisible substance cannot be conjoined with the whole of itself because of the separateness of its parts, occupying distinct positions in space from one another. No body, then, is of such a nature as to revert upon itself in such a way that the whole is reverted upon the whole. If, therefore, there is anything that is capable of reverting upon itself, then it is incorporeal and without parts. (Translated after Dodds)

Proclus is here attempting to secure the general premise that nothing corporeal can achieve self-reversion and the reflexive consciousness that accompanies it.34 For a body to revert on itself, both the reverting part and the part reverted upon must become conjoined resulting in the two parts becoming one. That is what self-reversion means. But this is impossible for a body. Imagine a body consisting of two parts A and B, each occupying a distinct position in space. If the body were to revert upon itself, then A and B would come to occupy the same space, which is impossible. The implication here is that if the soul has the capacity to reflect on itself (if it is capable of self-reversion), then it cannot be a body of any kind; it must be incorporeal.35

3.2.2 Separability Proposition 16 supplies the other crucial premise for the immortality argument: ‘Everything that is capable of reverting on itself has existence separable from all body.’ Again, this follows from the capacity for self-knowledge. Self-knowledge, 33

Dodds 1963, 202. Proclus is again relying on the Neoplatonic conception of a body (soma) as a substance composed of spatially distinct parts (what the Epicureans would call a ‘compound body’). 34 Dillon and Gerson 2004, 267. 35 Simplicius (in DA 187, 27ff.) later extends this argument to the sensory soul (a move not found in Proclus and rejected by Porphyry): ‘It is also shown in this way that our rationality penetrates as far as sense-perception, if it is the case that human sense-perception is able to know itself. This is so because in a way what is perceiving knows itself, when it knows itself while it perceives. And for this reason it reverts upon itself and belongs to itself, and its being separate from bodies already shows through more, insofar as every body having different parts of itself in different places would never be able to turn its attention to itself.’

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like all acts of self-reversion, is an activity carried out in separation from the body.36 However, whatever has a separate activity must itself have a separate existence (cf. ET 44, 83): For if it were inseparable in substance from any body (achoristou tes ousias somaton ouses), it is impossible that its activity should be separable, since it is impossible that, if a given substance be inseparable from bodies, the activity that proceeds from that substance should be separable. For if that were the case, the activity would be superior to the substance in that the latter would need a body while the former would be self-sufficient, being dependent not on bodies but on itself. (ET 16, 2–8 translated after Dodds)

So if the soul is capable of reflecting on its own activity, then it must be capable of existing apart from its body.37 Both arms of Proclus’s Achilles argument are joined together in ET 186, preparing the way for the final proof of the immortality of the soul in ET 187: Proposition 186: Every soul is an incorporeal substance and separable from body. For if it knows itself, and if whatever knows itself reverts upon itself [prop. 83], and what reverts upon itself is neither a body (for all body is incapable of reverting on itself [prop. 15]) nor inseparable from body (for, again, it is not the nature of what is inseparable from body to revert on itself; for in this way it would be separated from body [prop. 16]), it follows that soul is neither a corporeal substance nor inseparable from body. But that it knows itself is obvious. For if it has knowledge of principles superior to itself, then it is all the more able to know itself, as it derives self-knowledge from its knowledge of the causes prior to it. (Translated after Dodds)

Since the soul is capable of knowing itself, it is capable of reverting on itself, and is therefore both incorporeal and separable from body. It follows from this that the soul cannot be destroyed either by decomposition or by being severed from its bodily substrate (ET 187).

36

This seems to follow from ET 15. Since no body is capable reverting on itself, the activity of self-reversion cannot be one that is accomplished through the body. 37 Proclus is likely drawing on Porphyry Sentences 41: ‘For that which is able to know itself without that which it is in, withdrawing itself from it and being able to do this without encompassing its own destruction, can in no way owe its essential existence to that from which it was able to turn itself to itself (strephein heauto eis heauto) without undergoing destruction and to know itself without that.’ Porphyry continues that the fact that the senses cannot do this shows that they ‘have acquired their efficacy through the medium of the body.’ Dillon traces the connection between selfreflection and separability back to Aristotle at DA 430b24–6. However, Porphyry himself seems to be drawing directly on DA III.2, 425b13–26, which argues that none of the five senses are capable of reflecting on their own activity. (See also Theaetetus 184Cff.) Philoponus, writing in the 6th century, offers a similar argument at in DA 466,19–28: ‘But if it [the soul] reverts on itself, then it would have an activity which is separate [from body], and what has a separate activity has a separate existence and on that account is eternal and incorporeal.’ Philoponus explicitly argues that the sensory soul cannot be eternal and therefore cannot revert on itself: ‘The senses are not eternal, and for that reason do not revert on themselves. And if they do not revert on themselves, they do not lay hold of their own activities. For a thing’s reverting on itself is none other than its laying hold of its own activities.’

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3.3 Ancient Origins The move from separability to immortality is not original to Neoplatonism. In De anima II.1 Aristotle defines the animal soul as the actuality of the living body, which he identifies with its form. Towards the end of that chapter he remarks that this definition entails that the animal soul is inseparable from body (413a4–7): The soul is an actuality in the same way that sight and the power of the tool are, while the body is that which exists potentially. And just as the korê and the power of sight make the eye, so too the body and the soul make the animal. Thus, it is quite clear that neither the soul nor certain parts of the soul (if it naturally has parts) can be separated from the body; for in some cases the actuality belongs to the parts [of the body] themselves.

However, Aristotle goes on to say that there is nothing to prevent other parts of the soul from being separable, if they are not the actuality (or power) of any part of the body. This is confirmed in DA III.5, where he argues that the intellect is imperishable on the grounds that its activity does not have a share in anything bodily and thus is capable of separate existence. Another version of this argument appears in Generation of Animals II.3, 736b13–737a17. Although Aristotle does not draw the conclusion that the intellect is imperishable, its separability is again invoked as an important premise. Aristotle’s main concern in GA II.3 is to determine how the parts of the soul could be transmitted from the father to the embryo in the act of reproduction. Since the semen is eventually destroyed (it evaporates), it cannot serve as a vehicle for transmitting any parts of the soul that are actualities of bodily organs. For those parts cannot survive the destruction of their seminal vehicle (736b21–5): Clearly those capacities of soul whose activity is bodily cannot be present anywhere without a physical body; for example, the capacity to walk cannot be present anywhere without feet. And this also rules out the possibility of those capacities of soul entering [the embryo] from without (since it is impossible for them to enter on their own) as well as their entering by being transmitted in some body. For semen is a residue of nutriment that undergoes a change.

The exception is again intellectual soul. Since the activity of this soul does not involve a bodily organ (736b28–9: outhen gar autou têi energeiai koinônei sômatikê energeia), it alone is capable of separate existence and so could survive the destruction of its bodily vehicle. For this reason, Aristotle says, intellect alone enters the embryo from outside by being transmitted in the father’s semen.

3.4 Mereological Objections To close this chapter I want to explore what I see as the central weakness of Plotinus’s unity argument, what we have termed the ‘narrow’ Achilles. The problem, I shall argue, is that it relies on an impoverished model of composition wherein a

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whole is identical to its parts.38 Surprisingly, this was the model of composition endorsed by the ancient Atomists, who were among Plotinus’s primary targets. For example, Democritus is reported to have held that as the atoms move through the void they collide and become entangled in such a way as to cling in close contact with one another ‘but not so as to form in reality one substance of any kind whatsoever, for it is very simple-minded to suppose that two or more things could ever become one’ (Aristotle On Democritus ap. Simplicius in DC 295,9). Yet, this was not the only model of composition available to Plotinus. Indeed, as we shall see, it was a model that Plato himself rejected. The model of composition that Plato develops in its place is meant to preserve the idea of a whole as a genuine individual composed of parts rather than a mere collection or heap of them.39 I shall argue that Plotinus’s unity argument rests on his failure to avail himself of this richer model of composition. Recall Plotinus’s unity argument. Plotinus notes, for example, that when we perceive a complex object like a face we do not have one perception of the nose, a separate perception of the eyes, and so forth, but a unified perception of the face as a whole. Similarly if we were to perceive the face talking, we do not experience the sound as something distinct from the face; we perceive everything together as a unified whole. In order to explain this, Plotinus argues, all these different perceptions must be grasped by some one thing. Otherwise, it would be as if I perceived the eyes, you perceived the nose, and so forth, so that no one would ever perceive the face as a whole. According to Plotinus, this means that the central consciousness cannot be a body of any kind. For a body is composed of spatially distinct parts, which could never yield the kind of unity necessary for experience. Suppose the central consciousness was a body (soma) and that it was divided into parts corresponding to the parts of the sense object. How would it perceive the whole object? Let us suppose (to take a very simple picture) that we identify the central consciousness with a certain area of the brain; its parts would be the individual neurons that comprise that area.40 According to Plotinus, this leads to a trilemma. Suppose we say that there is an awareness of the whole object in virtue of each neuron being aware of a part of it. The perception of the object would be distributed over the neurons in such a way that their activation collectively yields an awareness of the object as a whole. Plotinus will argue that unless there is a single substance to which all these sub-perceptions report, our experience of the object would be fragmented into isolated perceptions and we would never have a unified experience

38

In this section I am concerned with Plotinus’s understanding of the composition of bodies (corporeal unity) rather than souls (incorporeal unity). It should be noted that Proclus’s version of the Achilles argument avoids the problem I identify below (though it seems to suffer from its own serious problems). 39 See Verity Harte, Plato on Parts and Wholes: the metaphysics of structure (Oxford: Clarendon Press, 2002). 40 The primary targets of Plotinus’s trilemma are the Stoics and Aristotelians, who both identify the central consciousness (what the Stoics call the hegamonikon and the Aristotelians call the common sense) with the heart.

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of the whole. This substance, moreover, must be incorporeal. For if it was itself a body divisible into spatially distinct parts, then the problem would arise all over again. However, suppose we reject this first alternative and say the brain possesses an awareness of the object even though none of the individual neurons is aware of anything. Plotinus will argue that this is impossible. For how could the brain be aware of something if none of its parts was? Finally, we might say that the brain has an awareness of the whole object in virtue of each neuron being aware of the object as a whole. This would preserve the unity of the perception, but not in the desired way. First, each of the neurons themselves would have to be an indivisible unity (and thus incorporeal), or else the problem arises again for each neuron. Second, if each neuron perceived the whole object, there would be as many perceptions as there were neurons. In that case there wouldn’t be one unified perception of the whole object but a multitude of them, which contradicts experience. I want to argue that Plotinus is too quick in rejecting the second alternative (‘Or will the parts of the parts [of the ruling principle] lack perceptions? But that is impossible!’). His dismissal of this option seems to rest on the idea that any property of the whole must ultimately be a property of its parts. Why? I suggest this is because he subscribes to a model of composition that Verity Harte calls composition as identity.41 According to this view, a whole is identical to, and so is nothing but, its parts; it is not a new substance generated from them.42 Since there is no higher-level entity corresponding to the whole, Plotinus might argue, it cannot be said to have any properties of its own. Any higher-level properties must ultimately belong to the lower-level entities that make it up. This rules out the second option of the trilemma: the brain cannot be conscious of the whole object if none of its neurons are. And since the other two alternatives (each neuron is aware of part of the object or each is aware of the whole object) are equally problematic, it follows that the central consciousness cannot be a body of any kind; it must be an incorporeal unity. Plotinus seems to have in mind here an analogy between a corporeal consciousness perceiving an object and a crowd of people staring at a painting. How could the crowd be said to have a single perception of the picture? The first option is that the crowd perceives the whole picture in virtue of each person perceiving a separate part of it. However, in that case the perception of the painting would be fragmented into isolated perceptions of parts and nothing would have an awareness of the painting as a whole. The third option is equally problematic. On this option each person in the crowd perceives the object as a whole, so that there wouldn’t be a single perception of the painting but a multitude of perceptions of the same thing. The second option also seems impossible on this analogy. For how could the crowd be said to perceive the painting if none of the people in the crowd do?

41

Harte 2002. As we shall see, this is a model of composition that Plato himself rejected. See Harte 2002 and below. Harte argues that Plato offers two alternatives to the thesis of composition as identity: the view of a whole as distinct from its parts (Parmenides 144E–145A), and the view of a whole as one thing composed of many parts (Sophist 244B–245E). According to Harte, Plato endorses the latter. 42

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If we treat the brain (or central consciousness) as a composite analogous to a crowd of people, then Plotinus’s trilemma certainly has force. The crowd cannot have any properties that do not belong to its individual members. For there is no crowd over-and-above the people (its parts); the crowd just is those people taken together. However, one might object to Plotinus’s dismissal of the second alternative by claiming that consciousness is an emergent property of the brain. According to Samuel Alexander, an emergent property is a higher-level property that ‘emerges from the lower level of existence and has its roots therein, but it emerges therefrom, and it does not belong to that level, but constitutes for its possessor a new order of existent with its special laws of behavior.’43 However, if one accepts the model of composition as identity (the brain just is the neurons), there would be no higher-level entity for consciousness to be a property of. In that case, the higher-level property (consciousness) must not only have its roots in the lower-level entities (the neurons), it must also belong to that lower-level. It follows that each neuron must either be aware of part of the object (in which case our experience would be fragmented) or be aware of the object as a whole (in which case there would be a multitude of experiences of the same thing). Neither would yield a single, unified experience. To block this move one would need a model of composition that treats certain kinds of wholes as genuine individuals. This would put the second alternative back on the table. On this alternative, consciousness will be a property of the brain (some single entity) that emerges from its lower-level parts but without belonging to that lower-level.44 To find such a model of composition Plotinus need only have turned to his master, Plato. Verity Harte offers the most complete account of Plato’s theory of composition.45 According to Harte, there are three essential features of the Platonic model. First, structure is an essential ingredient in the constitution of a Platonic whole.46 Second, composition is restricted. There are constraints on the sorts of 43 Alexander 1920, 46 (emphasis added). The idea of an emergent property would not have been unfamiliar to Plotinus. According to Caston, Galen had already come to the idea of an emergent property (Caston 1997, 309–363). Aristotle also seems to be reaching for some such notion in Parts of Animals II.1. Although the idea of ‘emergent properties’ has generally been met with contempt by contemporary philosophers, it is an entirely legitimate concept in biology: ‘With each step upwards in the hierarchy of biological order, novel properties emerge that were not present at the simpler levels of organization. The emergent properties result from interactions between [lower-level] components. A molecule such as a protein has attributes not exhibited by any of its component atoms, and a cell is certainly much more than a bag of molecules. If the intricate organization of the human brain is disrupted by head injury, that organ will cease to function properly, even though all its parts may still be present.’ (Campbell and Reece 2002, 4) The concept of emergent properties emphasizes the importance of structure in an organized whole, which lies at the heart of the Platonic (and Aristotelian) model of composition. 44 This model would require positing some sort of supervenience relation between the higher-level property and the lower-level base. Thus we could say that the brain’s awareness of the whole object supervenes on the activity of the neurons that compose it. 45 Harte traces the subtle development of Plato’s conception of parts-and-wholes across a number of different dialogues. 46 Harte 2002, 208. By ‘ingredient’ Harte does not mean in the sense of being a material component of the whole but in the sense that a whole can be analyzed into material components (or

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things that can combine to produce genuine wholes.47 Crowds of people and flocks of sheep are not genuine wholes, since they do not possess the requisite structure. Finally, composition it is creative. It generates something new that was not there before by imposing structure on parts that are themselves ‘structure-laden’.48 For Plato, then, a whole is not a mere collection of parts but ‘some single form’ (mian tina idean) possessing a distinctive nature of its own.49 My aim here is not to endorse the Platonic model of composition but rather to point to a way out of Plotinus’s trilemma. The way out, I am suggesting, is to show how a whole body (soma) can possess a single awareness without its parts possessing that awareness (the second arm of the trilemma). The key is to treat consciousness as an emergent property of the brain. This solution requires adopting a model of composition that treats a body as one thing composed of many parts, ‘not in the sense in which an aggregate is one thing but in the way that a syllable is’ (Aristotle Metaphysics Z17, 1041b12–14; cf. Theaetetus 203E). I am not suggesting that one needs to adopt the Platonic model of composition in order to avoid the trilemma. But that would have been the most natural option for a Neoplatonist. And since Aristotle also endorses a similar model, it is all the more strange (if I am right) that Plotinus opted for the identity thesis. That view of parts-and-wholes would have been more at home in Epicureanism than Plotinus’s Neoplatonism.

elements) and structure. (Compare the sense in which Aristotle calls matter and form as ‘parts’ of a composite in Metaphysics ⌬ 25.) For this feature of Platonic wholes see Harte’s analysis of the Philebus (Chapter 4, §4.3). Harte also argues that, for Plato, structure is essential to the identity of the parts themselves. On this reading the parts of a Platonic whole cannot be identified independently of the whole that they compose; they are (as Harte puts it) ‘structure-laden’. Thus we should not think of structure as something imposed on independently specifiable elements. 47 Harte 2002, §3.4. 48 Harte 2002, e.g. 156; 194. This view of composition as something creative obviously commits Plato to a thicker ontology. Contrast Democritus’s thinner ontology of ‘only atoms and void.’ 49 Compare Socrates’s description of the syllable at Theaetetus 203E. In Metaphysics Z17 Aristotle endorses this richer notion of composition exemplified by a syllable. There Aristotle speaks of the kind of whole ‘which is composed of something in such a way that the whole is one, not in the sense in which an aggregate (sôros) is one, but in the way that a syllable is’ (1041b12–14; cf. Metaphysics ⌬ 26, 1023b27–30: ‘That which so contains its contents that they form a unity . . .in the sense that the unity is composed from them.’). According to Aristotle, such wholes are not merely their parts taken together but include something else besides these which makes those parts one thing (e.g. a syllable or an organism). This ‘something else’ will not be another element but a single form, which he identified with the substantial being (ousia) of the whole. Although both Plato and Aristotle take syllables as paradigm wholes, had they known, they would have preferred the molecule. For example, a water molecule (H2 O) is not just the atoms H and O; if it were, then we would have water simply by placing two hydrogen atoms next to one oxygen atom. But that isn’t the case. Only when those atoms bind together in a certain way do they make a water molecule. This bond is not itself an atom but something else.

Chapter 4

The Unity of the Soul and Contrary Appetites in Medieval Philosophy Henrik Lagerlund

4.1 Introduction The history of the so-called Achilles arguments in the Middle Ages is largely unwritten. In his otherwise informative work, Mijuskovic only deals with the Middle Ages in one page and he is then mostly concerned with Thomas Aquinas.1 Although quite a lot has been published lately on medieval conceptions of the soul, not much attention has been given to these arguments. In this article, I will try to amend this to some extent, although a proper treatment requires a whole monograph. Following the terminology developed in the introduction to this book, I will deal with the broad and the narrow Achilles arguments, and I will trace these in the works of Augustine, Avicenna, Thomas Aquinas, John Peter Olivi, William Ockham and John Buridan. It will become apparent from my discussion of these authors that no Christian medieval thinker, except perhaps Olivi, accepts the broad Achilles argument. Their reason for not accepting it seems to be that they think it proves too much and ultimately puts limits on God’s omnipotence. Most of them will accept the narrow argument, however. A medieval thinker that accepts both arguments explicitly is Avicenna, and his outline of the two arguments becomes the main source for later medieval thinkers’ knowledge of them. After Aquinas and Olivi the notion of the simplicity and unity of the soul becomes a commonplace repeated by most medieval thinkers in one way or another, but with Ockham a new twist to the argument can be observed. He uses the notion of the soul’s simplicity as a premise in a paradox. Together with the notion of inner emotional conflicts and the principle that no contraries can exist in the same subject at the same time, the soul’s simplicity forms a dilemma that many subsequent thinkers had to comment on. Buridan, as will be seen, formulates a very influential

H. Lagerlund Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 80508, Fax: (519) 661-3922 e-mail: [email protected] 1 See Mijuskovic (1974), 12.

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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solution to this dilemma. Both the dilemma and Buridan’s solution found their way into the works of many early modern authors.

4.2 Augustine on the Simplicity of God and Soul Gareth Matthews has noted two arguments in Augustine’s De trinitate for the incorporeality of the soul,2 but neither of them seems inspired by the Neoplatonic argument from simplicity, that is, the broad Achilles argument. Both arguments can be found in Book X, Chapter 10, of De trinitate. After having discussed various positions on the nature (essence or substance) of the intellective soul (mens or animus in his terminology), Augustine writes that: All these people overlook the fact that the mind knows itself, even when it seeks itself, as we have already shown. But we can in no way rightly say that anything is known while its substance is unknown. Wherefore, since the mind knows itself, it knows its own substance. But it is certain about itself, as is clearly shown from what we have already said. But it is by no means certain whether it is air, or fire, or a body, or anything of a body. It is, therefore, none of these things.3

The argument takes its starting-point in the mind’s knowledge of itself, and since it knows itself, it knows it is not any body. The second argument is very much related to the first, but it is nonetheless a bit different and closer to Aristotle’s argument in De anima III, 4 (see below for a discussion of the argument). Augustine writes that: For [the mind] thinks of fire in the same way as it thinks of air or any other bodily thing of which it thinks. But it can in no way happen that it should think of that which itself is, in the same way as it thinks of that which it itself is not. For all these, whether fire, or air, or this or that body, or that part, it thinks of by means of an imaginary phantasy (per phantasiam quippe imaginariam); nor is it said to be all of these, but one or the other of them. But if it were any one of them, if would think of this one in a different manner from the rest.4

Augustine does not argue that whatever nature the mind has impedes it from thinking that nature, but that the mind instead would think differently about that nature. If it is fire, for example, it would think of itself, that is, fire, without having a representation of fire. As Matthews goes to great length to establish, Augustine holds that we can only think of material things representationally, that is, we need a mental image of them, but since the mind is directly present to itself without any representation it cannot be material.5 The force behind these arguments is Augustine’s notion of self-knowledge or perhaps the more mysterious notion of something being directly present to itself. The focus on self-knowledge is, of course, in line with general Platonic and Neoplatonic 2

See Matthews (2005), 43–52. See Augustine, On the Trinity, X, 10, 56. 4 Ibid., 56–57. The translation has been corrected. 5 See Matthews (2005), 46–52. 3

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doctrine, but Augustine makes a different use of it and presents some really original arguments. As we will see later on in this article, John Peter Olivi will make much use of this aspect of Augustine’s conception of the soul. Mijuskovic notes in his monograph on the Achilles argument that Augustine does not use the argument from simplicity in order to establish the immortality or incorporeality of the soul.6 He is, however, as Mijuskovic also notes, well aware of the argument. Augustine refers to the argument in Book VI of De trinitate, which is about the unity of the virtues and the simplicity of God. He there explains that the virtues, although meaning different things, converge in the human soul and cannot be separated from each other. Although the human soul is simple, it is not as simple as the eternal mind of God, which is simplest and eternally unchanging. In God, the virtues are one and the same, but: for the human mind (animus) it is of course not the same thing to be, and to be courageous and sagacious or just or moderate; it can be a human mind and have none of these virtues. But for God it is the same thing to be as to be powerful or just or wise or anything else that can be said about his simple multiplicity or multiple simplicity to signify his substance.7

Augustine seems quite happy to accept the argument from simplicity for God, but he seems not to think it is applicable to the human soul. The reason, which Mijuskovic gives, seems to be that he thinks it proves too much. If human souls were such simple things, then questions arise about their possible preexistence, and also about whether God could destroy them, that is, accepting the broad Achilles argument seems to put limits on God’s omnipotence. A little later in Book VI Augustine goes on to explain that he thinks that there are grades of simplicity in spiritual things. God is the simplest spiritual thing and human souls are, although spiritual, less simple. He writes that: [w]hen we come to a spiritual creature such as the soul, it is certainly found to be simple in comparison with the body; but apart from such a comparison it is multiple, not simple. The reason it is simpler than the body is that it has no mass spread out in space, but in any body it is whole in the whole and whole also in any part of the body. Thus when something happens even in some tiny little part of the body that the soul is aware of, the whole soul is aware of it because it does not escape the whole soul even though it does not happen in the whole body. And yet even in the soul it is one thing to be ingenious, another to be unskillful, another to be sharp, another to have a good memory; greed is one thing, fear another, joy another, sadness another; some of these things can be in the soul without others, some more, some less; countless qualities can be found in the soul in countless ways. So it is clear that its nature is not simple but multiple. Nothing simple is changeable; everything created is changeable.8

As pointed out in the very last sentence of the quote, everything simple is unchangeable, but the human soul is changeable; hence, it cannot be simple since only God is unchangeable.

6

See Mijuskovic (1974), 11–12. See Augustine, The Trinity, VI, 6, 209. The translation has been slightly modified. 8 Ibid., VI, 8, 210–211. 7

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In other writings, Augustine very eloquently stresses the divisions in the soul. In the Confessions, for example, he explains how his soul is torn apart by inner conflict.9 Such inner conflicts cannot exist in a simple soul. All this points towards the conclusion that Augustine does not accept the Achilles arguments. He stresses, as seen in what I have quoted, that material things have parts and hence they cannot be simple. The soul is simpler, but nonetheless not a simple thing. Only God qualifies as a true unity and simple substance on Augustine’s picture. Augustine’s view of the soul is very close to Plato’s in the Republic, but as will become clear his apparent rejection of the narrow Achilles argument had little or no effect on the subsequent tradition. I will argue, however, that his rejection of the broad Achilles argument had a profound effect on the whole medieval philosophical discussion of the soul. Very few, if any, Christian thinkers in the Middle Ages will accept it, since it seems to put limits on God’s omnipotence.

4.3 Avicenna on the Unity and Immortality of the Soul Augustine’s doctrine of the simplicity of God was very influential, but he is not the source of the medieval use of the Achilles arguments, as we have seen. There were other sources, however, and one of the most important was the Islamic philosopher Ibn Sînâ (Avicenna). He was himself influenced by Neoplatonism and tried very hard in his psychological writings to make Aristotelian psychology compatible with a Platonic conception of the soul. The argument from simplicity is visible in several places of his works and is one of the main arguments he gives for the incorporeality of the human soul. In my discussion, I will foremost be looking at the Kitâb al-Najât (The Book of Salvation), but the presentation there is the same as in the psychological part of the Kitâb al-Shifâ’ (The Book of Healing) only more condensed. The presentation in the Shifâ’ was translated into Latin and referred to as Avicenna’s De anima.10 The chapter of the Najât that includes the argument from simplicity is about the immortality of the human soul.11 This chapter contains two related arguments for the incorruptibility and immortality of the soul. The first argument is an argument for the incorruptibility, and it proceeds by showing that the body and the soul are independent entities. Anything corruptible is corrupted by the corruption of something

9

See Augustine, Confessions, VIII. In Book VIII, Augustine finds himself torn between the intellectual love of God and his lust for more worldly things. There is also a fascinating discussion of inner conflicts in William James’ The Varieties of Religious Experience, 153, and another locus classicus is, of course, Aristotle’s discussion of incontinence in the Nicomachean Ethics (see I, 13, for example). For a discussion of so called inner conflicts in the Ancient tradition see Price (1995). 10 See Hasse (2000). 11 See Khalidi (2005), 48–52; Rahman (1952), 58–63. The corresponding discussion in Avicenna, Liber de anima seu sextus de naturalibus, V, Chapter 4, 113–126.

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else, which it is dependent on. The body is such a thing or entity, but the soul is independent of the body and is hence not corrupted with it.12 Having said this, he continues by stating that the concepts of corruption and persistence are opposed to one another and as he says: ‘two different states of one thing.’13 He then writes that: [w]e say that it is possible for composite things and simple things that subsist in these compounds to combine the actuality of persistence with the potentiality of corruption; however, simple things that are separate in essence cannot combine these two features.14

The combination of these concepts is possible in the sense that in a human being, which is a composite thing consisting of a body and a soul, these two concepts can be combined, but the soul, being a simple thing, cannot have both. He continues by saying that: ‘[i]f the soul is absolutely simple and not divisible into matter and form, it will not be receptive to corruption.’15 A little further down on the same page he writes: It is obvious that everything that is simple and not composite, or is the origin and basis of something composite, will not combine the potentiality of persistence with the potentiality of annihilation in relation to its essence. If it has the potentiality of annihilation, then it is impossible for it to have the actuality of persistence. And if it has the actuality of persistence and existence, then it does not have the potentiality for annihilation. Thus, it is clear that the substance of the soul does not contain the potentiality for corruption.16

As noted, the argument aims at establishing that the soul cannot have both these potentialities. Perhaps a clearer way of stating the argument is the following: (P1) Souls exist. (P2) Souls have simple essences. (P3) The potentiality of corruption and the potentiality of persistence are opposed to one another. (P4) A simple essence cannot include opposed potentialities. (C1) Souls cannot include opposed potentialities. (C2) Souls do not include the potentiality of corruption. I am assuming that ‘existence’ and ‘persistence’ are the same thing, that is, if something exists, it persists and vice versa. This means that the soul in question is already has a potentiality for persisting and this, by simplicity, excludes the soul from also having the opposed potentiality of corruption. It is of interest to note given what I said above in relation to Augustine that Avicenna explicitly uses an example of opposed potentialities to show that the soul cannot be corrupted and is hence immortal. 12 For a short comment on the argument see Rahman (1952), 107–108. See also Thomas Aquinas, Summa theologiae Ia, q. 76. a. 6, for a similar argument for the soul’s incorporality. 13 Khalidi (2005), 51. 14 Ibid. 15 Ibid. 16 Ibid., 51–52.

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Both Augustine and Avicenna are influenced by Plato’s discussion in the Republic, IV, but they draw different conclusions from it. The principle used by Avicenna above (P4) will become very important later although slightly reformulated (see the section on Ockham). Avicenna goes on to show that matter or body can have both these potentialities. He explains that: [a]s for corruptible beings, they are composite and conjoined, and the potentiality of corruption and persistence are not in the concept by virtue of which the composite is unitary, but rather in the matter, which has the potentiality to receive two contraries.17

From this it is clear that Avicenna accepts the broad Achilles argument, which also of course means that he accepts the narrow argument. Although, it seems assumed in the above argument, it becomes clear a little later in the Najât where Avicenna discusses the unity of the soul that he also endorses the narrow argument. I will quote the whole passage, since it is exemplary, and serves as background to the later Latin discussions of this argument. Avicenna writes: [W]e sometimes say, ‘When I perceived such-and-such, I became angry’. Since this is a true statement, it is one thing that perceived and then became angry. That one thing is either the human body or the human soul. If it is the human body, then it would either be the totality of its organs or some of its organs. But it cannot be the totality of its organs, for it does not include the hand or the foot. It also cannot be two different organs, one of which perceived and the other became angry. For then it would not really be one thing that perceived and then was angry. It is also not the case that one bodily organ – according to someone who makes such a statement – is the object of both perception and anger. Rather, the truth is that the statement ‘I perceived and then became angry’ means perhaps that something within us perceived and something within us was angry. But the intention of one who utters, ‘I perceived and then became angry’, is not that this occurs to two things within us, but rather that the very thing to which perception conveyed this concept then became angry. Therefore, either the [literal] meaning of the statement is false, or else the truth is that the one who perceived and was angry in one thing. But since this statement is obviously [literally] true, then the thing to which perception conveys its perceptible is the very thing that becomes angry. And since it has such a position, even if it is a body, it does not have this position insofar as it is a body. Instead, it has it by virtue of having a faculty that makes it suitable for the combination of these two things. This faculty is not physical, and it must therefore be a soul.18

It must be one thing that unites all perceptions and emotions and to which the ‘I’ in the statement discussed in the quote refers. This one unitary and simple thing is the soul. Avicenna, as seen, accepts both the broad and the narrow Achilles argument. Given the profound influence of Avicenna’s psychology on the Western tradition, it seems clear that it was primarily through him medieval thinkers knew about the Achilles arguments.

17

Ibid., 52. Ibid., 54–55. The unity of the soul is also discussed in Avicenna, Liber de anima seu sextus de naturalibus, V, Chapter 7, 154–174. See also Yrjönsuuri (2006) for a comment on this passage. 18

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4.4 Thomas Aquinas on the Simplicity of the Soul In a famous passage, already referred to above, in De anima III, 4 (429a13–429b4), Aristotle argues that the intellective soul cannot have a specific nature, since it can think all things and if it had a nature, that nature would impede it from thinking that same nature, and since the intellect can think about anything, it cannot have a nature. In a similar way, as we saw Augustine argue above, Aristotle argues for the soul’s separability from the body. For both Aristotle and Augustine, the intellective soul thinks of something through a phantasm or a representation, and if the soul already had a nature it could not represent that nature in the same way as the fingers cannot feel the same temperature it itself has. Aristotle’s argument, repeated and developed in detail by for example Alexander of Aphrodisas,19 can be seen and indeed was seen by the tradition as an argument for the intellective soul’s immateriality or unbodiliness. Thomas Aquinas takes the argument to heart and presents it in the Summa theologiae Ia, q. 75, art. 2 (reply), in the following way: For it is clear that through the intellect a human being can cognize the natures of all bodies. But that which can cognize certain things must have none of those things in its own nature, because that which exists in it naturally would impede its cognition of other things. In this way we see that a sick person’s tongue, infected with a jaundiced and bitter humor, cannot perceive anything sweet; rather, all things seem bitter to that person. Therefore if the intellectual principle were to contain within itself the nature of any body, it could not cognize all bodies. But every body has some determinate nature. Therefore it is impossible for the intellectual principle to be a body.20

The reason Aquinas stresses this particular argument is that it fits very well with his hylomorphic view of human nature. The soul is the form of the body on his account. It is an immaterial substantial form, which is the principle of life, and which also is self-subsistent in a weak sense. It is this last point that is important for the argument above. According to Aquinas, a human soul can exist apart from the body it informs, but it is not itself a hoc aliquid, since it does not have a complete nature, that is, it cannot be located in a genus-species structure. It needs to be united with a body to complete its nature. It is furthermore only united to body that it can do what it is intended for, namely to think and acquire knowledge, since it needs phantasms or representations to do this. The argument for incorporality or unbodiliness above lets him say that the soul cannot be a body of any kind, but it is at the same time weak enough not to threaten the status of the soul and its dependence on the body. The broad Achilles argument is clearly too strong, in Aquinas’s eyes. It gives as a conclusion a soul that is quite complete in its simplicity and independence. Like

19 20

See for example Alexander of Aphrodisias, De intellectu. 46–58. The same argument can be found in his commentary on De anima as well. See III, 7, 344–347.

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Augustine, Aquinas does not want such a strong conclusion, since he wants to argue for an essential or per se union between the body and the soul.21 In q. 75, a. 6, of the Summa theologiae, Aquinas gives a version of Avicenna’s argument for the soul’s incorruptibility, but significantly he does not mention the simplicity of the soul as an explicit premise. He writes that: corruption is found only where contrariety is found, since generation and corruption occur from one contrary to another. For that reason celestial bodies, which do not have matter subject to contrariety, are incorruptible. But there cannot be any contrariety in the intellective soul. For it receives [things in it] in keeping with the mode of its existence, and those things that are received in it are without contrariety. This is because even the concepts of contrary things are not contraries within intellect; instead, the same knowledge embraces contraries. Therefore it is impossible for the intellective soul to be corruptible.22

The intellective soul cannot include contraries since it is immaterial like the celestial bodies, and it hence not subject to corruption. The premise explaining why contraries cannot exist in a soul is conveniently suppressed, however, making the whole argument questionable.23 There are hardly any references in Aquinas works to the simplicity of the soul. He clearly does not think the human soul is a perfect unity or simple in the same way as he thinks God is simple.24 God is, however, perfectly simple, as Augustine had claimed, but the human soul is not. There is, however, some unity even in the sensory part of the soul. Aquinas expresses this most clearly in his literal commentary on the De anima. Picking up a discussion by Aristotle in De anima, III, 2, Aquinas asks whether we distinguish between sweet and white with different powers or not. We cannot say that we do this with different powers, however, since then ‘it would be as if distinct human beings were sensing: one sensing sweet, another white – e.g., if I sense this and you that.’25 If we were to argue as above, however, then it would be clear that sweet and white are different, but the distinction itself would not be clear, since: there must be one [person] asserting that sweet is different from white. For this is a single truth, namely, that sweet is different from white. Therefore this one thing must be asserted by the same [person]. But an assertion is the expression (interpretatio) of an interior

21

See Mijuskovic (1974), 12, for the same conclusion. Ia, q. 75, a. 6, co.: ‘Non enim invenitur corruptio nisi ubi invenitur contrarietas, generationes enim et corruptiones ex contrariis et in contraria sunt; unde corpora caelestia, quia non habent materiam contrarietati subiectam, incorruptibilia sunt. In anima autem intellectiva non potest esse aliqua contrarietas. Recipit enim secundum modum sui esse, ea vero quae in ipsa recipiuntur, sunt absque contrarietate; quia etiam rationes contrariorum in intellectu non sunt contrariae, sed est una scientia contrariorum. Impossibile est ergo quod anima intellectiva sit corruptibilis.’ 23 Contraries in the intellect are also discussed in q. 89, a. 5, but it does not get much clearer there either. 24 See Summa Theologiae, Ia, q. 3, art. 7, for a discussion of God’s simplicity. 25 See Thomas Aquinas, A Commentary on Aristotle’s De anima, III, 3, 312. See also Aristotle, De anima, III, 2 (426b18–23). 22

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apprehension. So just as there is one who asserts, so there must be one who intellectually cognizes and senses that sweet is different from white.26

The argument used by Aquinas in this quote is indeed very similar to the argument used by Avicenna, and both arguments seem to be modified versions of Aristotle’s argument in III, 2. The sentence ‘Sweet is different from white’ is a truth assented to by one person. It is only by uniting two perceptions or representations in one perceiver that it can be judged to be true. This is done in the common sense, according to Aquinas. Expanding on an obscure analogy by Aristotle about a point being at once one and two, he explains that: It can be taken as one insofar as it connects parts of a line as a common terminus. It can be taken as two insofar as we use the point twice: as the origin of one line, and as the end of the other. In this way we should understand that the capacity for sensing is spread into the organs of the five senses from one common source: from this source the capacity for sensing goes into all of the organs, and at this source all of the alterations of the single organs have their terminus. Therefore this capacity can be considered in two ways: in one way as it is a single origin and a single terminus of all sensory alterations; in another way as it is the origin and the terminus of this sense and this one.27

The unity of the perceptions takes place in one organ, namely, the common sense, but the parts of the sense judgment have their origin in different senses. Similar to Avicenna there must hence be one faculty, sense or power that unites the different perceptions and which does the judging. This can hence be seen as a version of the narrow Achilles argument, although the simplicity of the soul in never mentioned explicitly, but it is instead obviously the unity of perceptions in the sensitive soul that is addressed.

4.5 Peter John Olivi on the Unity of the Soul Peter John Olivi was a Franciscan and contemporary of Aquinas. He produced strong negative critiques of Aquinas and also for that matter of Aristotle.28 The thinker he held above Aristotle was Augustine, but this of course does not mean that he rejects all Aristotelian notions. The form/matter distinction is absolutely essential to his metaphysics and souls are at least in part substantial forms. In fact, Olivi argues quite originally that the soul is a composite of an immaterial substantial form and spiritual matter. This is in itself a complete substance, which is in life united to a body to form another composite.29 In his very interesting commentary on the second book of Peter Lombard’s Sentences, he devotes three long questions (qq. 49–51) to

26

See Thomas Aquinas, A Commentary on Aristotle’s De anima, III, 3, 312. Ibid., 314. 28 See Burr (1971). 29 For a general presentation of Olivi and his thinking see Pasnau (2005) and for a treatment of his concept of soul see Pasnau (1997). 27

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the nature of substantial forms in humans and to the question why the soul cannot only be a form. Questions 50 and 51 also have long appendices on the unity of substantial forms and the nature of the soul. Like Augustine, Olivi stresses self-knowledge. He in fact makes it a basic requirement and distinguishing mark of all living things. Even clams have some form of self-reflection, according to him, since he thinks that as soon as an animal has sensations, for example, touch, it also has some rudimentary self-reflecting ability. He also connects self-reflection with the unity of the soul and the self.30 The notion of the unity of the soul is a very important doctrine for Olivi, and in this sense he moves beyond his otherwise so beloved Augustine. In fact, the very first argument of question 49 states the Achilles. Question 49 is about whether the soul immediately informs all parts of the body, and in traditional scholastic fashion he begins be stating arguments against this view. This first argument proceeds from the disconnectedness of several of our bodily parts. He writes that: First, [it is argued] from the discontinuation of several parts of our body. These [parts] are discontinuous from each other, diverse in number and as a consequence they are not parts of one entity. They are furthermore not informed by one form, but many parts of our bodies are discontinuous from each other.31

He continues by giving examples. The blood is separate from the veins, and veins and nerves are separate from the bones in out body, etc. There are also heterogeneous and diverse species in us, for example, sensible species. I hence take it that he is, as part of this general problem of unity, also concerned with the unity of perceptions.32 All this is presented as examples for why there is no unity in us; only parts put together.33 In his answer to this objection, he notes that the truth is indeed as the objection describes it, if we only take into account the corporeal forms, which together with matter make up our body. As such we are mere heaps of continuous forms and matter put together, but this is, of course, not the whole story,since we also havea single simple form that unites us into an essential whole.34 He writes the following to explain: 30

See Yrjönsuuri (2006) for a discussion of this. John Peter Olivi, Quaestiones in secundum librum Sententiarum, II, q. 49, 1: ‘Primo, ex discontinuitate plurium partium corporis nostri. Quae enim sunt inter se discontinua, sunt numero diversa ac per consequens non sunt partes unius entis numero nec informantur a forma una numero; sed multae partes corporis nostri sunt inter se discontinuae; ergo et cetera.’ 32 For evidence of this see ibid., 14–15. 33 Ibid.: ‘Minor patet: quia sanguis non continuatur venis nec venae aut nervi cum ossibus, nec spiritus cum arteries aut nervis, et universaliter partes heterogeneae sue diversae speciei non continuantur realiter inter se, quia omnis continuatio oportet quod sit per unam formam continuam et continuantem.’ 34 Ibid., 13: ‘Ad primum igitur dicendum quod in corporibus solas formas corporales et extensas habentibus divisio continuitatis facit numerum plurium entium et suppositorum, in iis vero quae habent unam formam animae simplicem ad quam omnes partes corporis substantialiter connectuntur divisio continui non facit numerum entium sive suppositorum, sed tantum numerum partium eiusdem entis.’ 31

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The reason for this division is because a corporeal form cannot be a unity and a unification unless by continuous forms and their parts. In animated [entities], the soul can without this by its simplicity in a spiritual unity unite these [parts], which in accordance with the continuous forms are disjoint in it.35

The corporeal parts of the body are not parts of an essential unity, only a unity secundum quid, but by the simple soul the bundle of matter and corporeal form that is the body becomes a united whole; it becomes one thing. It is among the characteristics of the soul that it is simple and spiritual or immaterial. In fact, as he often states, something simple cannot be other than spiritual.36 In his own answer to the general question, that is, whether the soul informs the whole body, he stresses the same points when he writes that: [It should be responded to the question above] that the soul informs every part of its body. This is proved first by the unity of the entity and its being and existence. It is necessary that every part of one entity concur in one total, natural, integrated or whole constitution, but parts of the body cannot be assembled into one total, natural, constitution of an animal, unless everything is united and perfected by one soul. It is evident from the only essence of their matter, [that bodies] cannot be unities. [This cannot happen either] by one material and connected form, . . ., nor [can it happen] by one specific corporeal form, . . .; therefore it is necessary that this [happens] by one simple form, which we call the soul.37

The union of diverse parts into one being is through the simplicity of the soul. It is impossible for material things with parts to be essentially united; only creatures with a soul have this quality. There is no other medieval thinker that emphasizes the unity of the soul as much as Olivi. It is not only taken for granted, as it often is by medieval thinkers, but also repeated continuously through several long questions of the Sentences commentary.38 It is, however, foremost the unity of perception or the unity of our bodily parts that he repeatedly stresses, but he also uses argument that perhaps could be characterized as related versions of the broad Achilles argument. In q. 51, he argues

35 Ibid.: ‘Huius autem diversitatis ratio est: quia in habentibus solam formam corporalem non potest esse unio vel unitas nisi per continuationem formae et partium eius, in animates vero potest absque hoc esse per simplicitatem animae in sua unitate spiritualiter uniente ea quae secundum formam continuitatis sunt inter se disiuncta.’ 36 See for example ibid., q. 72, 22. 37 Ibid., q. 49, 8: ‘Quod anima informat omnes partes corporis sui. Et hoc probat primo unitas entis et sui esse et existentiae. Oportet enim quod omnes partes unius entis concurrant in unam totalem naturam constituendam et integrandam seu consummandam; sed partes corporis ad unam naturam totalem animalis constituendam non possunt congregari, nisi omnes uniantur et perficiantur per unam animam; constat enim quod ex sola essentia suarum materiarum non sunt ad hoc unitae nec per unam formam extensam et continuam, cum plures earum sint discontinuae, nec per unam specificam formam corporalem, cum ex se non habeant nec habere possint unam talem, cum respectu formarum corporalium sint diversarum specierum; ergo oportet quod hoc sit per unam formam simplicem quam dicimus animam.’ 38 See particularly q. 50 and its appendix.

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that if the intellect is the form of the body, then the human body would be intellective just as it is sensitive through the sensitive soul.39 It is impossible, however: for the former [that is, the intellect] to be shared with the body, because that sort of characteristic can belong only to simple matter that is spiritual or intellectual and is both ungenerable and imperishable in respect of such a characteristic. For, since the intellectual and free form is highest and most simple of all forms, the matter which of itself can be connected to it must be in the genus of the highest and most simple matter.40

Nothing material can be intellective, since such a property is characteristic of immaterial and simple things. An intellective soul can only be united to simple and spiritual matter. This is not quite the broad Achilles argument mainly because it is not really an argument as stated above, but more an assumption that immateriality and simplicity go together and that they are incompatible with corporality. He thus accepts the conclusion of the broad Achilles but refuses the state the actual argument. Another similar passage is: Also, simplicity and spirituality, by their nature, incomparably exceed corporeal extension and quantity. Therefore the essential simplicity and spirituality of the passive power of spirits incomparably exceeds every extension and quantity of anything corporeal. Therefore it is impossible for it to be subject or subjectible to any extended force or its action.41

This is an argument for the conclusion that corporeal things or bodies cannot act on spiritual things. It is indeed an argument for a very strong dualism between the extended and the spiritual, and the argument proceeds through simplicity. It also assumes that simplicity and spirituality go hand in hand. This is not explicitly the broad Achilles argument either, but again it comes very close. I find it significant, however, that he never, as far as I can tell, explicitly endorses the argument by simplicity for the immortality or incorporeality of the soul. If this is indeed the case, he, as well as all other Christian medieval philosophers, thinks it proves too much and threatens God’s omnipotence. Although given his view of the soul as an independent substance, he seems to be the Christian thinker that comes closest to accepting the argument. The followers of Olivi in the so called Franciscan tradition, that is, Henry of Ghent and John Duns Scotus, did not accept Olivi’s conception of the intellective soul and they did not accept the broad Achilles argument. They, however, think

39 Ibid., q. 51, 104–105: ‘Si enim pars intellective est eius forma, cum omnis material fiat in actu per suam formam; tunc sicut corpus humanum est vere sensitivum et vivum per animam sensitivam, sic erit vere intellectivum et liberum per partem intellectivam.’ 40 Ibid., 105: ‘Sed hoc est impossibile corpori communicari, quia tale non potest competere nisi materiae simplici et spirituali seu intellectuali et ingenerabili et incorruptibili respectu talis esse. Cum enim altissima omnium formarum et simplicissima sit forma intellectualis et libera: materia quae ad ipsam per se attingere poterit oportebit quod sit in genere materiae altissimae et simplicissimae.’ 41 Ibid., q. 72, 22: ‘Item, simplicitas et spiritualitas ex sua ratione excedunt incomparabiliter extensionem et quantitatem corporalem. Ergo essentialis simplicitas et spiritualitas potentiae passivae spirituum excedit incomparabiliter omnem extensionem et quantitatem cuiuscunque corporei. Ergo impossibile est quod alicui virtuti extensae aut eius actioni sit subicibilis vel subiecta.’

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that the soul is a unity and its simplicity is stated on occasion.42 It seems to become accepted doctrine that the intellective soul is immaterial and hence also a simple thing, but the argument from simplicity to immateriality is never endorsed. In Ockham the discussion takes a new turn, however, and focus seems to fall on a new problem.

4.6 William Ockham on Unity and Contrary Appetites As mentioned above both Augustine and Olivi stress the immediate self-knowledge or self-awareness of the intellective soul or mind, and at least Olivi made this the central requirement for the mind’s identity or unity. They were, however, not alone in this—Aquinas also stresses the self-awareness of the operations of our own intellects. It is important for his argument against Averroes’s notion of a universal intellect that we while thinking have experience of our own thoughts as our own. Even though our thoughts are universal, we still experience them as our own and we thus have experience of ourselves as united beings with both a body and a soul. Aquinas thinks that this disproves Averroes’s thesis.43 It is the same person that sees and thinks, and this unity is something we have an experience of.44 William Ockham, however, rejects this whole way of reasoning and simply denies that we have an experience of a unified individual. He does not think that this opens the door for Averroes’s thesis of a universal intellect, though, since conflicting intellectual acts are spread out among a population. For example, I hold the belief that the Swedish Prime Minister is in September 2006, a man called Göran Persson, while others might think he is in fact called Fredrik Reinfeldt and not Göran Persson. The mere fact that there are these contradictory beliefs held by different people shows that we cannot all share one universal intellect, since contrary states cannot exist in the same thing at the same time.45 The principle utilized by Ockham in the above argument is the same one used by Plato in the Republic and by Avicenna in the Najât. In Book IV, when Plato starts to investigate whether the soul contains the same divisions as the state, he uses the same metaphysical principle as Ockham. He writes that ‘it is evident that the same thing will never do or suffer opposites simultaneously in the same respect and in relation to the same thing.’ (Rep. IV, 436b8–9.) The principle is almost uniformly 42

See Henry of Ghent, Opera omnia, Quodlibet, II, 2; III, 14; IV, 13; and X, 5. See also Zavalloni (1951). 43 See Thomas Aquinas, Summa theologiae I, q. 76, a. 1, resp. See also Yrjönsuuri (2006), 164–165. 44 There are similarities between Aquinas’s argument involving the notions of self-reflection and the union of soul and body and Proclus’s version of the Achilles argument. See D. Henry’s contribution for an outline of Proclus’s argument. In general, however, the unity of the soul as used by Aquinas in his arguments against Averroes is not the same kind of unity that is at the heart of the Achilles arguments. 45 See William Ockham, Quodlibetal Questions I, q. 11, 59–60.

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accepted by Ancient and medieval philosophers and since Leibniz it has been called the law of non-identity of discernibles, and can be given the following formulation: (P) If F and G are univocal contraries, and both ‘x is F’ and ‘x is G’ are true, then ‘x’ must refer to two different things.

The reason I write ‘univocal contraries’ is that there must not be any equivocation with respect to F and G in sense, time or anything else. If there is the ‘x’ might actually refer to the same thing although F and G are contraries.46 Ockham often uses the above principle in his argumentation and it is used explicitly in arguing for why there must be two souls in each human being, namely a sensitive soul and an intellective. Such a position fits very naturally with his acceptance of the doctrine of the plurality of substantial forms.47 It is in combination with the notion of the soul’s simplicity, the acknowledgment that there can be so called inner emotional conflict in a human being, and (P), that it follows that there must be at least two souls in each human being. This problem seemed, as noted above, to be a part of the reason why Augustine denied the simplicity of the soul and it leads Ockham to argue for two souls in each human being. Each soul is a substantial form, according to Ockham. The sensitive soul is a material form extended as part in part, and the intellective soul is an immaterial form, similar to Olivi’s discussed above, and is whole in the whole body and whole in each part of the body.48 Such a soul is simple and cannot have contrary states existing in it at the same time, according to Ockham. In his Quodlibetal Questions, Ockham argues for a real distinction between the sensitive and the intellective souls. He gives three arguments but the main argument is the first and it is a version of the argument Plato used in the Republic. Ockham writes that: It is impossible that contraries should exist simultaneously in the same subject. But an act of desiring something and an act of spurning that same thing are contraries in the same subject. Therefore, if they exist simultaneously in reality, they do not exist in the same subject. But it is manifest that they exist simultaneously in a human being, since a human being spurns by his intellective appetite the very same thing he desires by his sentient appetite. (II, q. 10, 132–3)

Ockham never argues for the simplicity of the intellective soul. It is something he accepts as standard doctrine and it together with (P) entails that the conflict we experience cannot be inside one soul but must be a conflict between two souls. The dilemma Ockham points to is implicit in Augustine and in Avicenna, as we have seen, and can be formulated in the following way: (i) P. (ii) The soul is simple and unified. (iii) There exist true inner conflicts.

46

See De Sousa (1987), 25. See Zavalloni (1951). 48 See Lagerlund (2004) for an outline of Ockham’s conception of the intellective soul. 47

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(i)–(iii) are inconsistent given that the inner conflict is between two univocally contrary states. Using the unification idea in the way Ockham does, as a premise in a paradox, was to become very common and a problem visible in many early modern thinkers. A medieval thinker explicitly addressing Ockham’s paradox was John Buridan.

4.7 John Buridan on Contrary Appetites In his commentary on Aristotle’s De anima, Buridan strongly argues against the Ockhamistic position described above. He does not believe that there are several souls in a human being. There is only one, which is vegetative, sensitive and intellective, but he still thinks that the soul is simple in the sense that there are no real distinctions within it. There is for instance only a nominal distinction between the intellect and the will, since ‘the soul is called “intellect” from the fact that it understands, and the same soul is called “will” from the fact that it wills.’49 This of course causes the same problem for him as it did for Ockham and he needs to find another way of solving the dilemma Ockham pointed to. He thinks this problem is so important that he devotes an entire question to it in his commentary, Question 18 of Book III, which is called, ‘Whether one appetite is contrary to another in a human being?’ The examples of inner conflicts he discusses are all from the discussion of incontinence in Aristotle’s Nicomachean Ethics, but the problem is for Buridan foremost metaphysical. In his answer to the question, he starts by making a distinction between an appearance, which he thinks can be both propositional and non-propositional, and the assent to that appearance. There can be contrary appearances or contrary propositions in the same soul at the same time, but there cannot be acts of assent to two contrary propositions at the same time. He explains this in a very clear way when he writes that: It must be noted that although we sometimes take ‘appearance’ broadly, as lending itself generally to every cognition, nevertheless, when it is taken strictly, there must be a great difference between the proposition, the appearance and the assent. For you are able to form a proposition without an appearance in such a way that it is or is not the case, e.g., that the stars are even in number, because you have no reason for one side or the other which is more naturally suited to cause the appearance of one side than the other. And finally there can also be appearance without assent. For to anyone looking in a mirror, there appears to be a threedimensional image in the mirror, although we know that this is not so. That is why we do not assent to but dissent from that appearance. And so someone touching a stone with his fingers crossed correctly produces in himself the appearance by touch that there are two stones, and yet he knows very well that there are not two. Also in this way, readily believable arguments

49

See McGrade et al. (2000), 514. For a general outline of Buridan’s concept of the soul see Zupko (2001), 164–182, and Lagerlund (2004). The latter article contains a discussion of Buridan’s critique of Aristotle’s argument in De anima III, 4, mentioned above. Buridan does not accept the argument and in that way opens the door for a more materialistic Aristotelian interpretation. He was in this respect very influential.

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H. Lagerlund on opposite sides produce appearance of contrary propositions at the same time for the intellect, but we do not assent to both. It was also stated in Question Sixteen of Book III of this treatise that propositions are not called contraries on the basis of the incompatibility of being in the same subject at the same time, but on the basis of the incompatibility of being true at the same time. But the acts of assenting to those contrary propositions would be contrary not only on the basis of the incompatibility of being true at the same time, but also on the basis of being in the same subject at the same time. Therefore, a human being can have contrary propositions at the same time, be they on the basis of different concepts or on the basis of sense and intellect. But the appearance of contrary propositions are also called contraries, either because they are contrary propositions, or because if they were separate, they would naturally bring about contrary acts of assent. Still, they cannot produce these acts in the same thing at the same time. . . .I will say, then, that appearances are not contraries on the basis of the incompatibility of being in the same thing at the same time, but they are called contraries (i) in the way that propositions are, i.e., on the basis of the incompatibility of being true at the same time; or (ii) they are called contraries because they belong actively to contrary acts of assent, . . .And so nothing prevents contrary appearances from being in the same person at the same time, as far as the intellect is concerned.50

It is the same thing with appetites. An appearance that something is good or bad generates what he calls a first motion of the appetite, but neither the appearance nor the first motion are contrary appetites, and this explains, according to Buridan, why a person can feel a disagreement and a pleasure towards the same thing at the same time. And I say that appetite does not follow upon the simple formation of a proposition, but it does follow upon the appearance that it is good or bad, worthy of pursuit or avoidance (and even more in this regard [does appetite follow] assent). But the appetite which follows upon the appearance that it is good is called love or agreement, and that which follows upon the appearance that it is bad is called hate or disagreement. And those appetites are usually called the first motions of the appetite itself, and they are not contrary on the basis of the incompatibility of being in the same thing at the same time, just as the appearance which they follow upon are not. For this reason, it is manifest that someone who throws his goods into the sea feels in this act a great disagreement because of the appearance of loss, and yet it pleases him because of the appearance of his and the others’ being saved.51

There cannot, however, be fully-fledged contrary appetites in the same subject at the same time. Really strong appearances, immediately followed by an assent, are called efficacious appetites, which immediately cause pursuit or flight in non-human animals. I say that, with respect to the same object, the accepting efficacious appetite, to the extent that it naturally produces agreement with assent, and the rejecting efficacious appetite, to the extent that it produces disagreement with dissent, are truly mutual contraries, and cannot possibly exist in a human being at the same time.52

Basically, what Buridan does in his answer to Ockham is to bring back the famous Stoic doctrine of first motions. According to for example Seneca, there are three stages to an emotion. First, we feel a movement in our bodies which draws us 50 John Buridan, Questions on Aristotle’s De anima, III, 18, 418–420. For the Latin see pp. 201–203. 51 Ibid., 420–421, and for the Latin p. 204. 52 Ibid., 421, and for the Latin p. 205.

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towards an object or away from it; secondly, this movement causes a proposition in us saying that this object or happening is good or bad; and, thirdly, if we assent to this proposition we have a fully fledged emotion. The first movement is necessary and we cannot help feeling it, but we can always avoid assenting to the proposition that this object is good or bad, and hence we can always avoid having the actual emotion, according to Seneca.53 Buridan accepts Seneca’s theory, and he uses it to account for the dilemma of combining the simplicity of the soul with inner conflicts. Buridan is very clear on the whole dilemma and he bases his answer to it on his theory of cognition and soul in general. It is questionable whether his solution properly accounts for the psychological phenomenon of inner conflicts as expressed by Augustine and Ockham, but it is interesting that this specific Stoic doctrine resurfaces to account for it.54

4.8 Conclusions In this article, I have argued that Augustine does not accept either the broad and or the narrow Achilles arguments and that he is not the source of the use of these arguments in the Middle Ages. Avicenna seems more likely to be the source for knowledge about these arguments. He accepts them both and gives a clear exposition of his versions of them. I have furthermore argued that very few, if in fact any, Christian medieval thinker accept the broad Achilles argument, since they seem to think it puts limits on God’s omnipotence. The only Christian thinker that comes close to accepting it is Olivi. His concept of the human soul makes it possible for him to endorse the argument and he very nearly does, but in the end it seem to me that not even he accepts it. Aquinas does clearly not accept the broad argument, but he gives a clear exposition of versions of the narrow argument, which is very similar to Avicenna’s version of it. Following Aquinas and Olivi, the notion of the intellective soul’s unity or simplicity becomes a commonplace and is repeated by most medieval thinkers. Ockham also thinks the intellective soul is simple, but he uses the notion as a premise in a paradox together with the notion that there are so called inner emotional conflicts in the soul and the principle that there cannot exist contraries in a subject at the same time. The solution to this paradox, according to him, is that there must be two souls in each human being and that the conflict we experience is a conflict between souls and not within a soul. Buridan explicitly address Ockham’s paradox, but finds a solution that allows him to argue that there is only one soul in each human being. Both the paradox and Buridan’s solutions became very influential. 53

For an account of Seneca’s view of emotions see Sorabji (2003) and Knuuttila (2005). For an account of Buridan’s view of action and incorporation of the Stoic doctrine of first motions see Lagerlund (2002). 54 Buridan’s solution is very similar to Descartes’ and in a sense, they both try to explain away the whole problem. For Descartes’ discussion of the problem see Section 47 of The Passions of the Soul (AT XI, 364–365; CSM I, 345–346). Exactly the same solution can also be found in authors like Peter of Ailly, John Mair and Francisco Suarez.

Chapter 5

Hume, Spinoza and the Achilles Inference∗ Shannon Dea

5.1 Introduction Despite the pervasiveness of the Achilles inference in the history of philosophy, there are a number of major figures who never use it. Among these are Hume and Spinoza, who nonetheless figure large in the history of the argument – Hume due to his lengthy criticism of it in Treatise 1.4.5, and Spinoza because Hume invokes him throughout much of that criticism. Although Spinoza himself never uses the Achilles argument, there are three closely related Spinozist doctrines that might be regarded as resembling the Achilles: (1) that all bodies are modes of a single extended substance, (2) that all thoughts are modes of one single mental substance, and (3) that extension and thought are attributes of the very same substance. Like the Achilles argument, these doctrines seem to engage the problem of the One and the Many, ultimately holding that pluralities of beings are united by the single being in which they inhere. In fact, maintains Hume, the Achilles argument is so similar to S. Dea Department of Philosophy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1 Phone: (519) 888-4567, ext. 32778, Fax: (519) 746-3097 e-mail: [email protected] ∗ All Hume references are to David Hume, A Treatise of Human Nature, eds. David Fate Norton and Mary J. Norton (Oxford: Oxford University Press, 2000). Spinoza references are to Baruch Spinoza, Complete Works, trans. Samuel Shirley (Indianapolis: Hackett, 2002) and follow the standard abbreviation and citation practices for Spinoza. Other references are as follows: Pierre Bayle, The Dictionary Historical and Critical of Mr. Peter Bayle, 2nd ed. (New York: Garland, 1984, Facsimile of London: J. J. and P. Knapton, 1734–38), Vols. 3 and 5; René Descartes, Principles of Philosophy, The Philosophical Writings of Descartes, Vol. 1, trans. John Cottingham, Robert Stoothoff, and Dugald Murdoch (Cambridge: Cambridge University of Press, 1985); Alan Donagan, Spinoza (New York: Harvester-Wheatsheaf, 1988); Martial Guéroult, Spinoza I: Dieu (Éthique, I) (Paris: Aubier-Montaigne, 1968); Immanuel Kant, Critique of Pure Reason, trans. Norman Kemp Smith (London: Macmillan and Co., 1956); Ben Lazare Mijuskovic, The Achilles of Rationalist Arguments: The Simplicity, Unity and Identity of Thought and Soul From the Cambridge Platonists to Kant: A Study in the History of an Argument (The Hague, Martinus Nijhoff, 1974); Isaac Newton, The Principia: Mathematical Principles of Natural Philosophy, trans. I. Bernard Cohen and Anne Whitman (Berkeley: University of California Press, 1999).

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Spinoza’s arguments for the simple unity of substance that proponents of the former inevitably open the door to Spinozism. In what follows, I consider the analogy that Hume draws between the Achilles inference and Spinozism. Section 5.2 surveys a number of important formulations of the Achilles inference in order to clarify what I mean by ‘the Achilles’, while Section 5.3 focuses on the analogy that Hume draws between Spinozism and the Achilles. I argue that, in fact, Hume presents two classes of analogies, the first a sincere one that draws upon Hume’s theory of ideas and presents his own reading of Spinoza, and the second a polemical one based on Bayle’s attack on Spinoza. I pay special attention to the former, in particular to the similarities between Spinoza’s double-aspect theory and what I term Hume’s ‘epistemic parallelism’ between ideas and impressions. Section 5.4 considers whether Spinoza ever tacitly accepts the Achilles argument, either in his philosophy of mind or in his larger metaphysics, ultimately arguing that, since the Achilles necessarily engages plurality, and since Spinozism in its very constitution prohibits such engagement, the analogy that Hume draws doesn’t hold. Indeed, the very thing that prevents Spinoza from accepting the Achilles likewise prevents Hume from doing so. The Achilles inference in its various historical forms concerns the cognitive intersection between the One and the Many. However, no such intersection is possible for either Hume or Spinoza – for Hume, there is only complexity/plurality; for Spinoza, only simplicity/unity. Thus, a real analogy holds not between Spinoza and the Achilles, but between Hume and Spinoza. However, they also encounter analogous difficulties as a consequence of their respective positions. I conclude by sketching these.

5.2 Which Achilles Inference? The question of whether or not Spinozism is an analogue of the Achilles inference hinges on which argument exactly we take to be the Achilles. As it turns out, this is a thorny issue. While it seems clear that such figures as Bayle, Hume and Kant have the same argument in mind, they characterize it in different ways.1 Bayle’s articulation of the Achilles inference in note E of his article on Leucippus in his Dictionnaire historique et critique is devoted to proving the immateriality of the mind. Bayle takes the following line: 1. If a mind were a composite of parts, each part of the mind could only know the portion of the thought that inhered in it. 2. If this were the case, then the mind could never have a whole thought. 3. But the mind does have whole thoughts.2 1 Mijuskovic describes the Achilles as a proof ‘which began with the simplicity of the soul and concluded in the epistemological unity of consciousness’ (92). However, following Kant (A351–52), I take the Achilles to do the opposite: to begin with the epistemological unity of consciousness and conclude with the simplicity of the soul. 2 Notice that Bayle does not here stipulate that the mind has all and only whole thoughts – nor

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Therefore, the mind is not a composite. Over the course of his argument, Bayle draws upon numerous examples in order to illustrate the unity of thought; all of these emphasize not the mind’s essence but its function. He illustrates the problem with conceiving of thought as extended through recourse to such thought-acts as knowing an entire horse or tree, and feeling a unified pain. If a thinking substance were a composite of parts, argues Bayle, it would never see a whole tree or feel pain upon being struck by a stick: . . . the subject, affected with the whole image of these objects, is not divisible into many parts, and consequently that man, as a thinking being, is not corporeal, or a material, or divided or compounded of many things. If he were, he would be perfectly insensible of the stroke of a stick, since the pain would divide itself into as many particles as the member smitten consists of. But these members consist of infinite particles; so that the portion of pain, which belonged to each part would be too small to be perceived or felt. (3.790 E)

Thus, Bayle’s consideration of whether the mind is a composite hinges upon the plurality of material substance and the mind’s function of uniting this plurality. Kant’s full formulation of the argument, like Bayle’s, argues from the nature of composites to the simplicity of the mind: Every composite substance is an aggregate of several substances, and the action of a composite, or whatever inheres in it as thus composite, is an aggregate of several actions or accidents, distributed among the plurality of the substances. Now an effect which arises from the concurrence of many acting substances is indeed possible, namely, when this effect is external only (as, for instance, the motion of a body is the combined motion of all its parts). But with thoughts, as internal accidents belonging to a thinking being, it is different. For suppose it be the composite that thinks: then every part of it would be a part of the thought, and only all of them taken together would contain the whole thought. But this cannot be consistently maintained. For representations (for instance, the single words of a verse), distributed among different beings, never make up a whole thought (a verse), and it is therefore impossible that a thought should inhere in what is essentially composite. It is therefore possible only in a single substance, which, not being an aggregate of many, is absolutely simple. (A351–52).

This version has four main premises: The action of a composite is an aggregate of several actions distributed among the plurality of substances of which the composite is comprised. If thinking were such an aggregate action, then thoughts would be distributed among the mind’s component parts. Distributed representations can never make up a whole thought. But there are whole thoughts. Therefore, thought is only possible in a single, simple substance.

This is essentially Bayle’s version of the argument, but with Bayle’s unstated starting assumption rendered as the first premise. And, like Bayle’s, it makes explicit the Achilles inference’s engagement of the problem of the One and the Many. Indeed, in a move that engages the plurality of perceptions even more directly than Bayle does, Kant identifies as the ‘nervus probandi’ of the Achilles the proposition that does he need to. It is sufficient for Bayle’s argument that some of our thoughts are whole. Thanks to Robert Stainton for drawing my attention to this.

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‘if a multiplicity of representations are to form a single representation, they must be contained in the absolute unity of the thinking subject’ (A352). For Kant, the starting assumption of the Achilles is not the mind’s essential simplicity, but rather the need for the mind to unify the manifold in the act of cognition.3 That is, for Kant, it is precisely the plurality of perceptions that speaks most forcefully to the unity of the mind. Both Bayle’s and Kant’s versions of the Achilles argue from the unity of cognition and the plurality of perceptions to the necessity of a simple mind to unify those perceptions. The inference draws the conclusion that it does because of the premise – implicit in Bayle’s version and explicit in Kant’s – that the action or behavior of a composite cannot be simple but is itself divisible into component parts. While Mijuskovic (87) takes Hume’s mention at Treatise 1.4.5 of ‘one argument commonly employ’d for the immateriality of the soul, which seems to me remarkable’ to refer to the Achilles argument, the argument that Hume outlines bears little prima facie resemblance to Bayle’s and Kant’s versions.4 Hume’s description of the argument runs as follows: Whatever is extended consists of parts; and whatever consists of parts is divisible, if not in reality, at least in the imagination. But ’tis impossible any thing divisible can be conjoin’d to a thought or perception, which is a being altogether inseparable and indivisible. . . . Thought, therefore, and extension are qualities wholly incompatible, and never can incorporate together in one subject. (Treatise 1.4.5.7)

This account is very different from the Bayle-Kant characterization of the Achilles. Whereas the Bayle-Kant version starts with the unity of thought and infers from it the simplicity of the thinking subject, Hume’s starts with the indivisibility of thoughts and infers from this that they can only be locally conjoined with other indivisible (and, hence, unextended) things. Indeed, Hume is explicit that his formulation of the argument does not concern the subject of inherence for thoughts: ‘This argument affects not the question concerning the substance of the soul, but only that concerning its local conjunction with matter’ (Treatise 1.4.5.8). Not only is the conclusion of Hume’s version less ambitious than that of the Bayle-Kant version, but his arguments against the conjunction of thoughts and bodies are quite unlike theirs. Whereas the Bayle-Kant version of the Achilles emphasizes that simple actions (such as seeing a whole tree) can only be performed by simple beings, Hume focuses on the heterogeneity of thoughts and bodies. If a thought and an extended thing were conjoined, writes Hume, ‘woul’d the indivisible thought exist on the left or on the right hand of this extended divisible body? On the surface or in the 3

This tone in Kant’s version of the Achilles presages the transcendental move that he makes in his attempt to reveal the Achilles as a paralogism, to wit: ‘It is obvious that in attaching “I” to our thoughts we designate the subject of inherence only transcendentally, without noting in it any quality whatsoever – in fact, without knowing anything of it either by direct acquaintance or otherwise. . . . the simplicity of the representation of a subject is not eo ipso knowledge of the simplicity of the subject itself’ (A355). 4 See Lorne Falkenstein’s chapter in this volume for a close consideration of Hume’s version of the Achilles.

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middle? On the back- or fore-side of it?’ (Treatise 1.4.5.7). These are simply not the issues that animate Bayle and Kant. Moreover, the argument Hume outlines is a purely destructive one against the local conjunction of thoughts and bodies; he does not take the crucial next step and affirm the simplicity of mind. Were this passage in Hume to occur alone, there would be little reason to think that the ‘remarkable’ argument that he alludes to is the Achilles. However, by Treatise 1.4.5.15, Hume begins to shift gears. He writes: ‘But tho’ in this view of things we cannot refuse to condemn the materialists, who conjoin all thought with extension; yet a little reflection will show us equal reason for blaming their antagonists, who conjoin all thought with a simple and indivisible substance.’ His invoking of the controversy between the materialists and the idealists/dualists, hard on the heels of his reference to the remarkable ‘argument commonly employed for the immateriality of the soul’ (Treatise 1.4.5.7), suggests that the argument he has in mind really is the Achilles. Hume argues that the local conjunction problem is a double-edged sword that is as much a problem for the idealist/dualist as it is for the materialist. Just as thoughts, being indivisible, cannot be conjoined with bodies, so extended (and hence divisible) perceptions cannot be conjoined with a simple mind. Here, in Hume’s retort to the ‘Theologians’ (Treatise 1.4.5.16) on behalf of the materialists, we at last find him making reference, albeit polemical, to the hypothesis of a simple subject unifying a plurality of perceptions: ‘The free-thinker may now triumph in his turn; and having found there are impressions and ideas really extended, may ask his antagonists, how they can incorporate a simple and indivisible subject with an extended perception?’ (Treatise 1.4.5.16). By the time that, two paragraphs later, Hume turns his attention to ‘the question concerning the substance of the soul’ – despite his having ‘condemn’d that question as utterly unintelligible’ (Treatise 1.4.5.17) – his reference to the ‘doctrine of the immateriality, simplicity, and indivisibility of a thinking substance’ makes it clear that he is talking about the Achilles. In fact, in his analogy between Spinozism and the Achilles at 1.4.5.21, Hume even drops his 1.4.5.7 concern with the heterogeneity of thought and extension, and turns his attention to the possibility of a plurality of modes inhering in a simple substance of the same kind. That is, rather than considering whether thoughts and bodies can be conjoined, he considers whether many thoughts can inhere in one thinking substance. This is very much the concern of the Achilles inference as we find it expressed in Bayle and Kant. Even so, it bears noting that Hume’s take on the Achilles is a heterodox one. While his version ultimately does include reference to the simplicity of the thinking substance and to that substance’s role in unifying a plurality of perceptions, he ignores both the unity of cognition and the background assumption that we find in Bayle and Kant that composites can only have complex outputs.5 However, even if the argument that Hume parses at Treatise 1.4.5.7 is rather far from the usual

5

It should not be surprising that Hume neglects these aspects of the Achilles. He rejects both in his Treatise 1.4.6 discussion of personal identity.

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Achilles, by the time he invokes Spinoza at 1.4.5.17, the argument (or class of arguments) that he has in mind clearly belongs at least to the same family as the Bayle-Kant version.

5.3 Hume on Spinoza and the Achilles 5.3.1 Two Classes of Analogies Spinoza got dragged into the Achilles question unwittingly. He never uses the argument, nor indeed can he, given his philosophy of mind. However, in his Treatise 1.4.5 criticism of the Achilles, Hume invokes Spinoza as a kind of metaphysical bogeyman. Any argument levied against Spinoza’s claim that diverse modes inhere in a single, simple substance, maintains Hume, is equally fatal to the position that a simple soul can be the subject of inherence for a plurality of perceptions. He thus maintains that ‘the doctrine of the immateriality, simplicity, and indivisibility of a thinking substance is a true atheism, and will serve to justify all those sentiments, for which Spinoza is so universally infamous’ (Treatise 1.4.5.17). Hume thus poses a dilemma for proponents of the Achilles argument: Use the Achilles and you pave the way for Spinozism; deny Spinozism and you also deny the Achilles. Arguably, Hume’s modus operandi here is just the standard reductio argument of the eighteenth century, when to show that an opponent’s position entailed Spinozism was considered a sufficient refutation of it. However, the length to which he pursues the analogy between Spinozism and the Achilles suggests that the comparison was motivated not only by the requirements of his argument ad hominem, but also by what he genuinely perceived as a formal isomorphism between the two positions.6 This possibility is further underscored by the fact that in Treatise 1.4.5 Hume offers not one but two classes of analogies between Spinozism and the Achilles. The first concerns the parallelism that Hume describes between perceptions and objects.7 This discussion, I would argue, is close to Hume’s heart, and reveals a possible Spinozist influence on his theory of ideas. On the other hand, Hume’s second class of analogies draws heavily on Bayle’s attack on Spinoza, and seeks to turn Bayle’s own arguments against the ‘Theologians’ who use the Achilles argument to prove the existence of a simple, unified, immaterial, substantial soul. It is in this section

6

Mijuskovic also identifies a formal similarity (although a slightly different one) between the Achilles and Spinoza’s metaphysics: ‘There is a . . . strong comparison to be made between: (a) the conception of God “combining” what appear, at least to human beings, as subjectively “distinct” attributes in his essential simplicity (the so-called “problem of divine attributes” . . .); and (b) the unification of diverse concepts in one immaterial center of consciousness in human acts of cognition’ (11n.27). 7 ‘Objects’ is, of course, a loaded term for philosophers. I use it here as Hume uses it in Treatise 1.4.5 – that is, to refer to extra-mental objects.

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that we find Hume’s polemical reductio ad Spinozism.8 I shall consider this second class of analogies first, before moving on to Hume’s preceding, and arguably more serious analogy.

5.3.2 Bayle and the reductio ad Spinozism Hume’s second analogy between Spinozism and the Achilles considers three classes of attacks that are leveled against Spinoza, and turns each of them around to show that they pose just as much difficulty for Achilles proponents as they do for their intended target. Hume is careful to signal that the criticisms of Spinoza that he engages are not his own. Even as he introduces the first argument, he disassociates himself from it with the phrase ‘First, It has been said against Spinoza, according to the scholastic way of talking, rather than thinking . . .’ (Treatise 1.4.5.23). His introductions to the second and third classes of anti-Spinozist arguments – ‘Secondly, It has been said . . .’ and ‘Thirdly, It has been objected . . .’ (Treatise 1.4.5.24–25) – are less pejorative, but are still clearly intended to distance Hume from them. Hume draws all three of these arguments from Bayle. In the ‘Spinoza’ entry of his Dictionnaire, Bayle considers and rejects in turn the three closely related Spinozist doctrines that (1) all bodies are modes of a single extended substance, (2) all thoughts are modes of one single mental substance, and (3) extension and thought are attributes of the very same substance. However, Hume’s discussion at Treatise 1.4.5.22–26 draws upon only the first of these, focusing exclusively on note N.I. of Bayle’s ‘Spinoza’ entry. This is suggestive of Hume’s polemical intentions. Any of the three doctrines that Bayle attacks could provide Hume with useful fodder since (1) and (3) are both formally similar to the Achilles argument, and, on one view, (2) just is the Achilles argument writ large. However, Hume confines himself to the first doctrine because to do so is the most cutting to Achilles proponents. After all, as Hume surely knew, the Achilles argument’s main historical function had been as a refutation of materialism.9 Thus, to argue that the Achilles argument is actually formally identical to arguments for materialism was to hit the ‘Theologians’ where it hurts. Bayle understood substance for Spinoza as material substrate. In note N.I. of his ‘Spinoza’ entry, he discusses three problems that he regards as entailed by conceiving of God as substrate. First of all, he argues that extended things ex hypothesi possess parts. If everything that exists is either a substance or inheres in a substance, then each part of extended things is either a distinct substance (which Spinoza 8 I owe this phrase to Jeffrey K. McDonough who used it in a question and answer period following his presentation of ‘Leibniz’s Two Realms Revisited’ to the Canadian Society for the History and Philosophy of Science, at York University, Toronto, Canada, May 30, 2006. 9 On the Achilles as an argument against materialism, see Mijuskovic, 8–18, also Mijuskovic’s discussion at 62 of the Achilles as a response to Epicureanism, and Bayle’s reference in his Leucippus entry to ‘an insurmountable objection, to which their opinion is exposed, who maintain, that matter may think’ (3.790, E.).

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denies) or inheres in a substance which itself possesses no parts. For Bayle, this entails the absurd consequence that things extended in three dimensions in fact inhere in a perfect, unextended substance. Thus, Spinoza ‘must needs teach that extension is a simple Being, and as much compounded as Mathematical points. But is not this a most ridiculous assertion, and contrary to our most distinct ideas?’ (5.209, N.I.). Bayle’s second N.I. argument against Spinoza is based on the non-identity of discernibles. Bayle argues that, for any two things, P and Q, if P possesses a property that Q does not possess, then P and Q are really distinct, and hence separate substances. All of the parts of extended substance, argues Bayle, are therefore really distinct since each of them possesses unique properties that are not shared by the others. For instance, if we divide a foot into twelve inches, every inch in the foot is really distinct from every other inch since ‘I can affirm of the fifth [inch], that it is contiguous to the sixth, and I can deny it of the first and second’ (5.209, N.I.). Thus, argues Bayle, every modification of substance is itself a distinct substance. Bayle’s third N.I. refutation of Spinoza is much the same as his second, but rather than considering the real distinctness of parts of extended substance, he considers the incompatibility of various modes of that substance. Properties such as squareness and roundness do not subsist on their own, writes Bayle, but must inhere in an extended substance. However, the very same substance cannot at once be both square and circular. Incompatible modes require distinct substances: When therefore I see a round table, and a square table, in a room, I may affirm that the extension, which is the subject of the round table, is a substance distinct from the extension, which is the subject of the other table; for otherwise the square figure and the round figure would be at the same time in one and the same subject; which is impossible. (5.209, N.I.)

Thus, Bayle rejects as absurd Spinoza’s putative position that the very same substance may be at once both square and circular, both iron and water, wine and wood. In his second analogy at Treatise 1.4.5.22–25, Hume rehearses these arguments in the very same order in which they appear in Bayle, turning them one by one against the Achilles. Hume begins by considering Bayle’s first argument that Spinozism entails that extended things must inhere in an unextended point, agreeing that this ‘is utterly impossible and inconceivable unless the indivisible substance expand itself, so as to correspond to the extension, or the extension contract itself, so as to answer to the indivisible substance’ (Treatise 1.4.5.23). However, continues Hume, the very same absurdity is entailed by arguments for an unextended mind. On Hume’s view, perceptions10 of extension are themselves extended. If Bayle is right that it is absurd to make extended bodies inhere in an unextended substance, then ‘’tis plain, nothing is requir’d, but a change in the terms, to apply the same argument to our extended perceptions, and the simple essence of the soul’ (Treatise 1.4.5.23). That is, if Bayle is right that extended modes cannot inhere in an unextended substance, and if, as Hume argues, perceptions of extended things are themselves extended, then it follows that these perceptions cannot modify an unextended mental substance either. 10 Hume uses ‘perceptions’ to refer to ideas and impressions. See Treatise 1.1.1.1. Throughout this section, I use the term in this sense.

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In his treatment of Bayle’s next two arguments from N.I., Hume considers in turn the notions of substance as ontologically independent and as substratum. Hume reminds his readers that ‘we have no perfect idea of substance’ (Treatise 1.4.5.24),11 but, despite this, he considers the definition of substance as ‘something, that can exist by itself’ (Treatise 1.4.5.24). On this conception of substance, writes Hume, when Bayle argues that all of the modes of Spinozist extended substance are themselves substances, all that he can mean is that they can exist by themselves. Earlier, at Treatise 1.4.5.5, taking his cue from Descartes’ Meditation 6 separability principle, Hume had argued that since all perceptions are conceivable apart from everything else, they are therefore really distinct from everything else. Thus, if ‘substance’ is defined as ‘something that can exist by itself,’ then all perceptions are separate substances. Now, in his consideration of Bayle’s second N.I. attack on Spinoza, Hume invokes this earlier argument. The very same grounds that license Spinoza’s critics to regard Spinozist modes as independent substances, argues Hume, likewise oblige them to consider perceptions as independent substances, and not, as Achilles proponents would have it, the affections of a substantial mind. ‘And consequently [concludes Hume] the one hypothesis labours under the same difficulties in this respect with the other’ (Treatise 1.4.5.24). Having considered the account of substance as that which is capable of independent existence, Hume invokes the definition of substance as substratum in his discussion of Bayle’s third N.I. criticism of Spinozism: ‘It has been objected [writes Hume] to the system of one simple substance in the universe, that this substance being the support or substratum of every thing, must at the very same instant be modify’d into forms, which are contrary and incompatible’ (Treatise 1.4.5.25). In illustration of this, Hume cites Bayle’s example of the round and square table, arguing that, just as it is impossible for the same extended substance to be modified into a square table and a round one at the same time, so it is impossible for the same thinking substance to be modified into impressions of a round table and a square table at the same time. Hume concludes his Bayle-inspired triad of reductios by asserting that ‘It appears, then, that to whatever side we turn, the same difficulties follow us, and that we cannot advance one step towards the establishing the simplicity and immateriality of the soul, without preparing the way for a dangerous and irrecoverable atheism’ (Treatise 1.4.5.25). Again, though, it bears emphasizing that the ‘difficulties’ that Hume has enumerated are not his own, but Bayle’s. That is, his line of argument at Treatise 1.4.5.22–26 is not ‘such-and-such is true of Spinozism, but it is also true of the Achilles,’ but rather ‘those who hold such-and-such to be true of Spinozism must hold the same to be true of the Achilles.’ These three arguments, then, are pure reductios, and do not give Hume’s own account of Spinozism, nor, consequently, his position on whether there really is a formal similarity between Spinozism and

11

Indeed, at Treatise 1.4.5.17, Hume condemns the question concerning the substance of the soul as ‘utterly unintelligible.’ His discussions of substance at paragraphs 22–26 are entirely polemical, and do not token a commitment on Hume’s part to substance metaphysics.

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the Achilles inference. That Hume’s intention with this triad was to ridicule the champions of a simple, immaterial mind, and not to engage them in serious debate is further suggested by the fact that, at least with regard to the first two of the three arguments, the so-called Theologians would have had little reason to accept Hume’s analogy. Hume’s claims that there are extended perceptions and that individual perceptions are ontologically independent are essential for the first two arguments, but they would have been anything but obvious to the philosophers he was targeting.

5.3.3 Two Parallelisms In marked contrast with his polemical analogies at Treatise 1.4.5.22–26, Hume’s discussion at 1.4.5.17–21 offers not what ‘has been said’ against Spinoza, but rather his own account of Spinozism: The fundamental principle of the atheism of Spinoza is the doctrine of the simplicity of the universe, and the unity of that substance, in which he supposes both thought and matter to inhere. There is only one substance, says he, in the world; and that substance is perfectly simple and indivisible, and exists every where, without any local presence. Whatever we discover externally by sensation; whatever we feel internally by reflection; all these are nothing but modifications of that one, simple, and necessarily existent being, and are not possest of any separate or distinct existence. Every passion of the soul; every configuration of matter, however different and various, inhere in the same substance and preserve in themselves their characters of distinction, without communicating them to that subject, in which they inhere. The same substratum, if I may so speak, supports the most different modifications, without any difference in itself; and varies them, without any variation. Neither time, nor place, nor all the diversity of nature are able to produce any composition or change in its perfect simplicity and identity. (Treatise 1.4.5.18)

Hume continues that Spinoza’s ‘hideous hypothesis’ of a simple, unified substance supporting a plurality of diverse modes is ‘almost the same’ (Treatise 1.4.5.19) with the Theologians’ doctrine of a simple, unified mental substance binding together a plurality of perceptions. He demonstrates this by sketching an epistemic parallelism that falls out of his own theory of ideas. On Hume’s account, the only ideas we have of the world of ‘external existences’ come to us via our impressions of those existences. While Hume grants that it is possible that the mind-independent existence of things may differ from our impressions of them, we cannot even conceive of these sorts of external existences, except as empty concepts. That is, we can conceive that there might be such existences, but, since we have no impressions of them, we cannot conceive what they might be like. Thus, there are only two ways for us to understand external existences – either as ‘a relation without a relative’ (Treatise 1.4.5.19) or as the very same as our impressions. Either way, argues Hume, we cannot conceive of a specific difference between an external existence and our impression of it since, in the former case, we have a merely formal, contentless conception of the external existence, and in the latter, the external existence is the same as our impression of it. Thus, while we cannot be certain that our reasoning based upon our impressions of objects is applicable to the external world, Hume maintains that any relations among external

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objects that we discover through reasoning about those objects must necessarily also hold among our impressions of those objects. Thus, we can never ‘discover a connexion or repugnance betwixt objects, which extends not to impressions; tho’ the inverse proposition may not be equally true, that all discoverable relations of impressions are common to objects’ (Treatise 1.4.5.20). Having reached this conclusion, Hume compares the ‘two systems of beings’ presented by Spinoza and the Theologians, respectively. With regard to ‘the universe of objects or of body,’ writes Hume, ‘Spinoza appears, and tells me, that these are only modifications; and that the subject, in which they inhere is simple, uncompounded, and indivisible’ (Treatise 1.4.5.21). Then, when he enquires concerning ‘the universe of thought, or my impressions and ideas. . . . theologians present themselves, and tell me, that these also are modifications, and modifications of one simple, uncompounded, and indivisible substance.’ Despite the great hue and cry that, according to Hume, arises when we compare the two systems, the two hypotheses ‘have the same fault of being unintelligible, and . . . as far as we can understand them, they are so much alike, that ’tis impossible to discover any absurdity in one, which is not common to both of them.’ Not only are the two positions formally identical, argues Hume, but, more strongly, the parallelism that on his view holds between the universe of perceptions and (what we know of) the universe of external objects entails that any relation that reason tells us is impossible among external objects is likewise impossible among our perceptions. Thus, if, as the antagonists of materialism hold, it is impossible for ‘the sun, moon and stars; the earth, seas, plants, animals, men, ships, houses, and other productions either of art or nature’ all to inhere in a single, simple substance, then it is likewise impossible for our ideas of these things to inhere in a single, simple (mental) substance: We can never, therefore, find any repugnance betwixt an extended object as a modification, and a simple uncompounded essence, as its substance, unless that repugnance takes place equally betwixt the perception or impression of that extended object, and the same uncompounded essence. Every idea of a quality in an object passes thro’ an impression; and therefore every perceivable relation, whether of connexion or repugnance, must be common both to objects and impressions. (Treatise 1.4.5.21)

Above, I referred to Hume’s account of the two systems of beings as an ‘epistemic parallelism.’ I did so in order to at once recognize Hume’s nod here to Spinoza and to point to the important difference between their two parallelisms. On the one hand, within a discussion of Spinozism, one can hardly read Hume’s assertion that we can never ‘discover a connexion or repugnance betwixt objects, which extends not to impressions’ (Treatise 1.4.5.20) without recalling Spinoza’s famous proposition that ‘the order and connection of ideas is the same as the order and connection of things’ (E2P7).12 On the other hand, however, the parallelism that

12 See also Spinoza’s earlier TIE 41 argument that ‘if there were something in Nature having no interrelation with other things, and if there were also granted its objective essence (which must agree entirely with its formal essence), then this idea likewise would have no interrelation with other ideas; that is, we could make no inference regarding it.’

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Hume advances here is not the robust, ontological parallelism of Spinoza, but rather a more agnostic, epistemic parallelism. That is, Hume does not claim that there is a realm of extra-mental objects and a realm of perceptions, and that these two parallel each other. Rather, he argues that if there is an extra-mental realm, then whatever ideas we have of relations of connection or repugnance in that realm also hold in the realm of perceptions. Hume’s parallelism thus asserts neither the existence nor the knowability of a world of objects, but only that if there is such a world, then whatever we can know about it we can also know about our impressions and ideas of it. It is worth pointing out that this quasi-parallelism of perceptions and objects itself is a close relative of Hume’s theory of ideas and the parallelism he describes between ideas and impressions. However problematic Hume finds Spinoza’s monism, this passage suggests that he has a much higher opinion of Spinoza’s parallelism. Again, it is important to recall that the argument Hume offers here is not merely one of Bayle’s N.I. arguments stood on its head, but Hume’s own account of Spinozism and the Achilles inference, an account that is much influenced by his theory of ideas. Hume devotes considerably more space to this interesting and difficult argument than he does to the Bayle-isms, which he unceremoniously eliminates, like ducks in a shooting gallery. I suggest that in this argument, which, in some respects, reveals similarities not only between Spinoza and the Theologians but also between Spinoza and Hume himself, we find Hume’s sincere appraisal of Spinoza. Despite Hume’s occasional invective, his appraisal is not entirely unsympathetic; it is demonstrably more even-handed than Bayle’s is. His brief account of Spinozism at 1.4.5.18 is fair and accurate, and, although he ultimately finds Spinozism to be ‘unintelligible,’ he finds it no more unintelligible than other theories then in currency. And, as we have seen, through his epistemic parallelism, he obliquely links his own theory of ideas with Spinoza’s E2P7 doctrine of parallelism. In light of this, it is worth considering whether the analogy that Hume draws at Treatise 1.4.5.17–21 between the Achilles inference and Spinozism really holds.

5.4 Does Spinoza Have an Achilles Argument? 5.4.1 Finite Minds Spinoza’s parallelism prevents him from adopting the Achilles argument for finite – that is, human – minds. According to Spinoza, to grasp the nature of human minds, we must understand human bodies (E2P13Schol). On his view, these bodies are not proper substances, but rather finite determinations of the infinite extended substance – essentially, mere clusters of properties persisting together for a time through a conative principle (E3P6-7). Human bodies, for Spinoza, are composites of many individual parts of different natures, some liquid, some soft, and some hard, these parts themselves both affecting and affected by external bodies in a variety of ways (E2Post1-3,6).

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For Spinoza, every finite extended mode has a corresponding finite thinking mode (E2P7Schol). Thought is therefore ubiquitous throughout Nature, and is as multifarious as extension. These finite modes of thought corresponding to bodies just are minds, or, put differently, a mind is just the idea of a body. In this sense, all bodies – and not just human bodies – have a corresponding mind: . . . what we have so far demonstrated is of quite general application, and applies to men no more than to other individuals, which are all animate, albeit in different degrees. For there is necessarily in God an idea of each thing whatever, of which idea God is the cause in the same way as he is the cause of the idea of the human body. And so whatever we have asserted of the idea of the human body must necessarily be asserted of the idea of each thing. (E2P13Schol)

According to Spinoza’s parallelism, ‘whatever happens in the object of the idea constituting the human mind is bound to be perceived by the human mind’ (E2P12). Since the mind just is that perception, human minds ‘map’ human bodies, possessing objectively all of the qualities formally possessed by the bodies. Thus, like finite bodies, finite minds are neither proper substances, nor simple unities, but rather complex clusters of finite modes temporarily ‘bound’ together by their conatus. Just as bodies combine disparate properties in a composite that changes as it affects and is affected by other bodies, so minds combine disparate and evanescent ideas: ‘The human mind is capable of perceiving a great many things, and this capacity will vary in proportion to the variety of states which its body can assume’ (E2P14). Thus, Spinoza is explicit that ‘the idea which constitutes the formal being of the human mind is not simple, but composed of very many ideas’ (E2P15). Indeed, it is precisely in virtue of this complexity that, for Spinoza, human minds are superior to others. He writes that human minds surpass non-human (finite) minds since their objects are ‘more excellent . . . and contain more reality’: In proportion as a body is more apt than other bodies to act or be acted upon simultaneously in many ways, so is its mind more apt than other minds to perceive many things simultaneously; and in proportion as the action of one body depends on itself alone and the less that other bodies concur with it in its actions, the more apt is its mind to understand distinctly. From this we can realize the superiority of one mind over others, and we can furthermore see why we have only a very confused knowledge of our body . . . (E2P15)

Spinoza’s denial of the substantiality of the human mind clearly rules out his use of the strong variant of the Achilles argument that infers from the plurality of perceptions to the existence of a thinking substance. However, it might be objected that a weaker, more contemporary variant of the Achilles is still open to Spinoza. For instance, the present-day ‘binding problem’ engaged by cognitive scientists is a version of the problem that motivates the Achilles.13 However, it is a version that remains agnostic – or, indeed, indifferent – on the question of substance. In my discussion above, I twice referred to conatus – Spinoza’s name for individuals’ tendency to persist in their own beings – as binding together extended – and hence, according to Spinoza’s parallelism, thinking – modes into non-substantial

13

See Viger, Bluhm and Mosurinjohn, this volume.

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individuals. It might, therefore, be argued that Spinoza obliquely adopts a weak variant of the Achilles argument whose conclusion asserts the existence of conatus rather than that of thinking substance. While conatus is indeed (in some sense) the ‘tie that binds’ disparate modes, there are a number of good reasons to reject the view that Spinoza’s arguments for conatus are in fact Achilles arguments. The most straightforward of these is quite simply that Spinoza nowhere indicates that he considers an individual’s conatus as a simple unity. Indeed, his famous example of the blood worm in Epistle 32 would seem to rule this out. Spinoza describes ‘a tiny worm living in the blood, capable of distinguishing by sight the particles of the blood – lymph, etc. – and of intelligently observing how each particle, on colliding with another, either rebounds or communicates some degree of its motion, and so forth’ (Ep. 32). For such a worm, argues Spinoza, the blood would be like a whole universe, and each individual particle of the blood would be like a whole individual, rather than part of a larger whole. He continues that ‘all the bodies in Nature can and should be conceived in the same way as we have here conceived the blood.’ The totality of Nature is straightforwardly a whole. However, individual bodies within Nature are only considered as parts or as wholes depending upon the point of view from which they are perceived. Just as the blood worm regards the particles of the blood as separate individuals, so a smaller creature might regard smaller bodies within those particles as wholes. And, since all bodies have corresponding ideas, therefore finite minds too are only ever considered as individuals: As regards the human mind, I maintain that it, too, is a part of Nature; for I hold that in Nature there also exists an infinite power of thinking which, insofar as it is infinite, contains within itself the whole of Nature ideally, and whose thoughts proceed in the same manner as does Nature, which is in fact the object of its thought. (Ep. 32)

Since conatus, for Spinoza, pertains to individual bodies and minds, and not to Nature as a whole, if an individual’s conatus is itself an individual, then it is susceptible to the same infinite nesting of parts and wholes that Spinoza describes in Epistle 32. It is, therefore, no more a simple unity than the bodies and minds that it ‘binds.’ And, of course, if it is not an individual, then it is not a simple unity. Either way, the Achilles is ruled out. The second reason for doubting that Spinoza tacitly draws upon the Achilles in his considerations of conatus is that concept’s origins in Cartesian physics. Spinoza’s central statement of the principle of conatus occurs at E3P6: ‘Each thing, insofar as it exists in itself, endeavors to persist in its own being.’ This is just Spinoza’s metaphysical version of Descartes’ so-called ‘first law of nature,’ that ‘each thing, in so far as it is simple and undivided, always remains in the same state, as far as it can, and never changes except as a result of external causes’ (CSM 1:240). Spinoza captures Descartes’s reference to ‘external causes’ both in the Principles of Cartesian Philosophy and in the Ethics. In the former, in his proof of Descartes’s first law, he writes that ‘if we pay no attention to any external causes (i.e., particular causes) but consider the thing only in itself, we must affirm that as far as in it lies, it always perseveres in the state in which it is’ (PPC 2:14Proof ). We find the very same notion repeated at E3P4: ‘No thing can be destroyed except by an external

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cause.’ Spinoza expands on this in the proof for that proposition, writing that ‘as long as we are attending only to the thing itself, and not to external causes, we can find nothing in it which can destroy it.’ Descartes’s discussion of his first law continues that ‘nothing can by its own nature tend towards its opposite, or towards its own destruction,’ a formulation that admirably captures what Spinoza means by conatus. Both Descartes’s and Spinoza’s versions of this principle are precursors to the modern concept of inertia that finds its canonical expression in Newton’s Principia as the First Law of Motion: ‘Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by forces impressed’ (Newton 416). Prima facie, an inertial (or proto-inertial) principle is just not the kind of conclusion that one would expect to find in the Achilles – an argument, after all, explicitly dedicated to mind, not matter. And, more seriously, both Spinoza and Descartes use arguments quite unlike the Achilles to demonstrate their respective propositions concerning conatus. Both Spinoza’s argument for conatus at E3P6 and his discussion of Descartes’s first law in the Principles of Cartesian Philosophy hold that finite beings persist as they do in virtue of God’s perfection.14 The argument runs that individual things owe their existence/persistence to God’s perfection, a perfection that never falters. Thus, any change that these individuals undergo must be owing to external causes, and not to the nature of the individuals themselves. This argument is not only quite unlike the Achilles, but it reveals a completely different set of concerns from those raised by the Achilles. This becomes even more clear when we recall that the historical purpose for which the Achilles was invoked was to refute materialism. As Hume makes clear in the first analogy that he draws between Spinozism and the Achilles, the possibility that something that is not itself a thinking thing can bind extended things and their modes poses serious difficulties for proponents of the Achilles. Moreover, while individuals really are just collections of properties for Spinoza, the metaphor of ‘binding’ these collections together is arguably misleading. Conatus is not a belt cinching a bundle of things together; rather, it just is that bundle of things. If we conceive an individual thing as a crowd of people, the crowd’s conatus is the crowd itself. If one were to throw a large lasso over the crowd in order to bind it together, this would in fact change the character of the crowd. It would confine it more tightly, limit its movements, and so forth. On Spinoza’s view, the lasso is not the principle of persistence for the crowd, but rather the ‘external cause’ that undercuts that persistence.

14

The details differ a little between PPC and E3P6 since the former, following Descartes, invokes God as creator, whereas the latter treats particular things not as creations but as determinate modes of God’s infinite attributes. Thus, the divine perfection invoked in PPC is God’s constancy in his works, whereas the divine perfection that is relevant for E3P6 is Being simpliciter. Other than this difference, the arguments are the same.

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5.4.2 God’s Mind It seems clear that Spinoza cannot and would not employ an Achilles argument for human minds. However, it is well to recall that when Hume discusses Spinoza in the context of the Achilles argument, he does so not in virtue of his (Spinoza’s) philosophy of mind, but because of the appearance of an Achilles-type argument in his discussion of God. Specifically, Hume describes a strong analogy between the Achilles argument and Spinoza’s ‘hideous hypothesis’ that a simple, unified substance supports a plurality of diverse modes. It is therefore worth considering whether an Achilles-type argument does indeed play a role – either explicitly or implicitly – in Spinoza’s larger metaphysics. In Section 5.3.2 above, I observed that there are three closely related Spinozist doctrines that might be regarded as resembling the Achilles argument: (1) that all bodies are modes of a single extended substance, (2) that all thoughts are modes of one single mental substance, and (3) that extension and thought are attributes of the very same substance. Like the Achilles argument, these doctrines seem to engage the problem of the One and the Many, ultimately holding that pluralities of beings are united by single beings in which they inhere. However, I would argue that to regard Spinoza’s one substance as uniting the attributes of extension and thought is to commit a serious category error. And, while there is indeed a sense in which Spinoza’s simple substance unites pluralities of modes, it does so in a way that is quite at odds with the union with which the Achilles is concerned. The nature of the category error that I referred to with regard to the third doctrine, the union of attribute types, is suggested in the preface to Ethics 5 in Spinoza’s criticism of Cartesian interactionism: ‘What, I ask, does [Descartes] understand by the union of mind and body? What clear and distinct conception does he have of thought closely united to a certain particle of matter? . . . surely, since will and motion have no common standard, there cannot be any comparison between the power or strength of the mind and body . . .’15 For Spinoza, mind and matter are so radically incommensurable that no causal relation is possible between them. However, what makes them incommensurable is their numerical identity. Spinoza makes this explicit at E2P7Schol: ‘. . . thinking substance and extended substance are one and the same substance, comprehended now under this attribute, now under that. So, too, a mode of Extension and the idea of that mode are one and the same thing, expressed in two ways.’ For Spinoza, a mode of thought and its corresponding mode of extension are just the very same thing considered in terms of its objective reality and formal reality, respectively. A mind can no more affect a body than the word ‘body’ can affect a body. While it is appropriate to consider the relationship between various aspects of formal reality, or, by contrast, various aspects of objective reality, the only 15

E5Pref. In an April 2006 presentation to members of the Achilles Project, John Nicholas likened Descartes’s theory that the mind and body are united in the simple unity of the pineal gland to the Achilles inference. If this is right, then Spinoza’s explicit mockery here of Descartes’s position on the pineal gland is yet another reason to reject the view that anything like an Achilles argument is to be found in Spinoza.

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relationship that can hold between a being’s formal reality and that being’s objective reality is a non-causal correspondence relation.16 Thus, a finite mode of thought and a finite mode of extension do not add up to two entities, but one entity considered in two different ways. And, just as ‘a body’ and a body do not constitute a true plurality to be united by a single substance, so Spinoza’s infinite attributes are not separate entities requiring – or even susceptible of – union. Thus, Spinoza is explicit that even though two attributes are really distinct in the sense that we can conceive one without the help of the other, ‘still we cannot deduce there from that they constitute two entities, or two different substances’ (E1P10Schol). The Achilles argument is an inference from the Many to the necessity of the One. We find no parallel inference in Spinoza’s doctrine of infinite attributes since, for him, there simply is no Many. This is also the right line to take regarding the purported isomorphism between the Achilles and Spinoza’s doctrine of the inherence of multiple modes in the single substance. That is, with modes as with attributes, since there really is no Many for Spinoza, it is not the case that substance as One is required to unite the Many. However, the details here are a little different from the attribute question. For one thing, the relationship in which two modes of the same attribute stand to one another is quite different from the one that holds between a body and the idea of that body. Two bodies, for instance, are just two different determinations of indeterminate extended substance. These bodies’ objective realities differ from one another, as do their formal realities.17 Moreover, two modes of the same attribute are distinguished by their respective conatus. Unlike a body and the idea that corresponds to it, two finite modes of the same attribute are not numerically identical. Thus, it would seem that these two bodies are susceptible of uniting in a way that the idea of a body cannot properly speaking be united to that body. Indeed, to see an Achilles-type argument here is tempting. After all, as I discussed above, Spinoza holds that finite thoughts and bodies are complex. He is also famously committed to the simplicity of the substance in which they inhere.18 In his early ‘Metaphysical Thoughts,’ Spinoza discusses this simplicity in terms of God’s thought: ‘[In God there is only one simple idea.]. . . . God’s idea through which he is called omniscient is unique and completely simple. For in actual fact God is called omniscient for no other reason than that he has the idea of himself, an idea or knowledge that has always existed 16

Of course, it may be argued that, since a being’s formal and objective realities are constantly conjoined, they share a Humean causal relation. However, Spinoza has no reason to quarrel with this since all that he denies is that mind or body can actually exert causal efficacy or force over the other. Humean causation is not his concern. In any case, Humean causes and effects are really distinct from each other; the same cannot be said of a being’s formal and objective realities. My thanks to Thomas M. Lennon for pointing this out to me. 17 In general, this is true of thoughts as well. However, Spinoza accepts that it is possible to have ideas of ideas. Thus, sometimes two ideas can stand in the same non-causal correspondence relation that I outlined above for modes of different attributes. 18 As Donagan notes, however, ‘no student of Spinoza . . . agrees with any other about all the major issues in interpreting him’ (xiii). Thus, Guéroult and Donagan both deny the simplicity of substance, taking God’s attributes to be really distinct. See especially Guéroult 428–61, and Donagan 77–93.

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together with God’ (CM 2/7). This dual emphasis on the simplicity of the substance in which pluralities of complex modes inhere, and on the unity of that substance’s cognition makes clear why Hume perceives an analogy between Spinozism and the Achilles. What separates the Achilles from Spinozism are the two doctrines’ positions on the priority of the One and the Many. Put simply, for Spinoza, the Many is not a real plurality, but just a partial conception of the One. The Achilles inference, on the other hand, regards the Many as in some sense prior to the One. Recall Kant’s ‘nervus probandi’: ‘if a multiplicity of representations are to form a single representation, they must be contained in the absolute unity of the thinking subject’ (A352). The classic Bayle-Kant form of the Achilles crucially treats the plurality of perceptions as prior to the unifying of that plurality by the simple subject. Bayle’s example of the tree helps us to see this. The tree’s top really is separated from its bottom by all of the complex, divisible matter in between them, and would remain so separated if there were no thinking subject perceiving the tree. It is in the act of cognition that the mind unites these distinct percepts. There is simply no analogue to this in Spinoza. For Spinoza, there is nothing outside of the one substance, and therefore nothing independent of that substance in need of binding. He writes, ‘there can be no substance external to God, and consequently no such substance can be conceived’ (E1P14Proof ). The Achilles can allow mind to unite pluralities of perceptions without thereby undercutting its simplicity and unity since the plurality that it unites occurs independently of the mind. However, on Spinoza’s view, if there are pluralities susceptible of union, this necessarily undercuts the unity and simplicity of God since those pluralities must themselves be part of God. If Spinoza’s God is a simple unity (and he is), then nothing can ever require uniting. In my discussion, I have characterized the Achilles inference as crucially concerned with the One and the Many. I argue, following Kant, that the core of the Achilles resides in its commitment to a simple substance that unifies a plurality that is in some sense independent of that substance. Despite some similarities between the Achilles and Spinozism, I maintain that no strong analogy holds between them since Spinozism in its very constitution rules out such a substance-independent plurality. However, I have also shown that Spinoza understands finite minds and bodies to be complex, and modes of the same attribute to be numerically distinct from one another. It is extremely difficult to see how these doctrines could be on all fours with the perfect unity and simplicity of Spinoza’s substance. If there are two non-identical modes, then God would seem to have parts, and therefore be a complexity, a state of affairs that would disqualify Spinozism from resembling the Achilles for very different reasons than the ones I give above. An adequate treatment of this issue is well beyond the scope of this discussion. However, the short answer to the problem is simply that finite modes are not parts of God, but rather God’s infinite attributes partially conceived. Thus, in the Short Treatise, Spinoza maintains ‘that “part” and “whole” are not true or real entities, but only “things of reason,” and consequently there are in Nature neither whole nor parts’ (KV 1/2/44). Later, in Epistle 35, he argues that substance ‘is simple, and

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not composed of parts. For in respect of their nature and our knowledge of them component parts would have to be prior to that which they compose. In the case of that which is eternal by its own nature, this cannot be so.’ For Spinoza, finite modes are epistemic artifacts and not part of the ontological furniture of the universe. Of course, this only pushes the question back a level. If there are no parts – if substance is perfectly simple and finite modes are only partial conceptions of that substance – then what exactly is doing the partial-conceiving? Or rather, since we know that it must be God partially-conceiving himself, how and why does a simple unity conceive itself (a simple unity) partially? As Hume remarks vis-à-vis Bayle’s attempted refutation of Spinoza, ‘It appears . . . that to whatever side we turn, the same difficulties follow us’ (Treatise 1.4.5.26).

5.5 Conclusion: ‘The Same Difficulties Follow Us’ Whether or not Spinoza’s doctrine of finite modes is ultimately coherent, the fact remains that Spinoza never uses the Achilles inference. Indeed, he cannot do so in virtue of the Achilles’ engagement of the problem of the One and the Many, and his rejection of the reality of the Many. I would like to conclude by observing that Hume, who invokes Spinoza in his attack on the Achilles inference, is prevented from accepting the Achilles for parallel reasons. Hume’s atomism, his rejection of substance and necessary connections, and his denial of the mind and personal identity all mark his position as antipodal to Spinoza’s. Whereas, for Spinoza, there is no Many, for Hume there is no One. Or, more precisely, although Humean atoms are individual units, any connections between these units are (on Hume’s account) loose, evanescent and ultimately illusory. The only unity for Hume occurs in primitives that fundamentally resist binding. That is, Hume’s notion of unity precludes the union of the Many by the One. Just as Spinoza’s denial of plurality prevents him from employing the Achilles, so does Hume’s denial of unity. Just as Spinoza characterizes complexity as merely epistemic, Hume regards the appearance of simplicity as just that – appearance: What I have said concerning the first origin and uncertainty of our notion of identity, as apply’d to the human mind may be extended with little or no variation to that of simplicity. An object, whose different co-existent parts are bound together by a close relation, operates upon the imagination after much the same manner as one perfectly simple and indivisible, and requires not a much greater stretch of thought in order to its conception. From this similarity of operation we attribute a simplicity to it, and feign a principle of union as the support of this simplicity, and the center of all the different parts and qualities of the object. (Treatise 1.4.6.22)

That is, Hume rejects the Achilles not merely because it is the argument of the ‘Theologians’, but also (and more importantly) because, like Spinoza, he has no use for an argument concerned with the relationship that holds between the One and the Many. All that interests Hume is the Many. If Hume and Spinoza reject the Achilles for isomorphic reasons, they also thereby produce isomorphic difficulties. I suggested above that Spinoza’s characterization

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of finite modes as partial conceptions of a single, simple, universal substance risks incoherence. The issue, once again, is this: if substance is a simple unity, and if nothing exists outside of substance, then what causes this simple unity to appear in a fragmentary way as finite modes? Or, more bluntly, why does the universe seem so multifarious if it is a simple unity? Hume’s atomism faces an opposite but equally serious challenge. Recall his claim that ‘an object, whose different co-existent parts are bound together by a close relation, operates upon the imagination after much the same manner as one perfectly simple and indivisible.’ If all perceptions are, as Hume claims, ontologically independent, then it is not at all clear how even this illusion of unity (in either the perceiving subject or in the objects of perception) is possible. Just as it behooves Spinoza to account for the appearance of plurality, so the onus is on Hume to explain the cognitive appearance of unity. Even if it is only an illusion, the appearance of simplicity in a perfectly pluralistic universe seems every bit as incoherent as the appearance of variety in a perfectly simple one. Indeed, Hume wrestles with this very difficulty in his Appendix: . . . having thus loosen’d all our particular perceptions, when I proceed to explain the principle of connexion, which binds them together, and makes us attribute to them a real simplicity and identity; I am sensible, that my account is very defective, and that nothing but the seeming evidence of the precedent reasonings cou’d have induc’d me to receive it. If perceptions are distinct existences, they form a whole only by being connected together. But no connexions among distinct existences are ever discoverable by human understanding. We only feel a connexion or determination of the thought, to pass from one object to another. It follows, therefore, that the thought alone finds personal identity, when reflecting on the train of past perceptions, that compose a mind, the ideas of them are felt to be connected together, and naturally introduce each other. However extraordinary this conclusion may seem, it need not surprize us. Most philosophers seem inclin’d to think, that personal identity arises from consciousness; and consciousness is nothing but a reflected thought or perception. The present philosophy, therefore, has so far a promising aspect. But all my hopes vanish, when I come to explain the principles, that unite our successive perceptions in our thought or consciousness. I cannot discover any theory, which gives me satisfaction on this head. (Treatise Appendix 20)

Hume continues that there are two principles that he cannot render consistent – ‘that all our distinct perceptions are distinct existences, and that the mind never perceives any real connexion among distinct existences’ (Treatise Appendix 21). In fact, these propositions are not inconsistent with each other. However, an inconsistency emerges if we take the first of the two propositions as short-hand for the argument of the preceding paragraph, viz.: All our distinct perceptions are distinct existences. If distinct existences form the appearance of a whole, they must be connected together. Our distinct perceptions do form the appearance of a whole. Therefore, they must be connected together.

Recall that, by what I have termed Hume’s epistemic parallelism, any relations among objects that we discover through reasoning about those objects must necessarily also hold among our impressions of those objects. However, by Hume’s

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second ‘inconsistent’ proposition, above, the mind never perceives a real connection among distinct existences. Thus, the argument alluded to in the first of the two propositions concludes that there must be connections among distinct existences, while the second proposition denies that we ever perceive such connections. This directly violates Hume’s epistemic parallelism – the very principle animating his first, sincere analogy between Spinoza and the Achilles. This should not be surprising since the argument that the first proposition alludes to resembles nothing so much as the Achilles inference. In sum, then, not only do Hume and Spinoza reject the Achilles for parallel reasons, but the very position that animates Hume’s rejection of the Achilles seriously undercuts his most earnest analogy between the Achilles and Spinozism. Indeed, the dejection that Hume notoriously falls into in the Appendix arguably centers on his inability to abandon the Achilles inference. If this is so, then despite his energetic attack on it, it is the Achilles that forces from Hume the following confession: ‘. . . I neither know how to correct my former opinions, nor how to render them consistent. If this be not a good general reason for scepticism, ‘tis at least a sufficient one . . . for me to entertain a diffidence and modesty in all my decisions.’19

19

My thanks to Lorne Falkenstein, Thomas M. Lennon, Robert Stainton, and Benjamin Hill for their assistance with this chapter. I also gratefully acknowledge the financial support of the Social Sciences and Humanities Research Council of Canada’s Doctoral Fellowships program.

Chapter 6

Locke and the Achilles Argument Jean-Pierre Schachter

There is an argument for the existence of an immaterial substance that seems to have had its first clear expression in Plotinus,1 but has recurred in a number of different forms until perhaps the beginning of the 20th C. Its most famous incarnation is in Kant’s first Critique, in which he dubs it ‘the Achilles of all dialectical inferences.’2 In deference to Kant and for the sake of a convenient label, I refer to arguments of this kind generically as ‘Achilles’ arguments, though the details of them vary considerably. What, then, is an Achilles argument? The Achilles is an argument that attempts to infer from data that are directly accessible to us the existence and nature of an entity that is theoretically inaccessible to us. More specifically, it attempts to infer the existence of a simple (‘indivisible’, ‘without parts,’ ‘unextended’) substance from the data of the different kinds of ‘unity’ that are found in our common human experience. Historically, the argument has then gone on to infer immateriality from the simplicity of that substance, and, ultimately, its immortality. For example, and most commonly, the Achilles attempts to move from the fact that human beings can simultaneously hear, see, smell, touch, etc., to the existence of a simple human subject-substance, a soul, that is necessarily immortal. There are a number of variants on this theme, notably ones arguing

J.-P. Schachter Department of Philosophy, Huron University College, The University of Western Ontario, 1349 Western Road, London, Ontario, Canada N6G 1H3 Phone: (519) 438-7224 e-mail: [email protected] 1 Plotinus, Enneads IV.7.6 2 Immanuel Kant Critique of Pure Reason, trans. by Norman Kemp Smith (New York: St. Martin’s Press, 1965) A351.

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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from the unity present in self-awareness,3 in judgment,4 and in the synthesis of past, present, and future into a self.5 This paper consists of two sections, the first of which considers Locke’s views on the Achilles applied to the human mind, the second on his application of the Achilles to God. In Section 6.1, I first identify three Lockean objections to the Achilles reasoning, and then two independent objections to the Achilles conclusion. In Section 6.2, I draw attention to the odd fact that while Locke strongly rejects the Achilles reasoning with respect to the human mind, he explicitly but inexplicably proceeds to apply it to the divine mind.

6.1 The Achilles and the Human Mind 6.1.1 The Five Objections In order to understand Locke’s objections to the Achilles, we must see that the argument’s structure is that of a disjunctive syllogism in which the two alternative accounts of human thought are respectively composite and simple substance. While the actual historical arguments are generally stated in terms of material and immaterial substance, they all hinge on the key properties of compositeness and simplicity. The argument characteristically proceeds by reducing the composite (material) alternative to absurdity by putatively demonstrating the incompatibility of the unity of consciousness with composition. The rejection of the composite alternative is then used to conclude by disjunctive syllogism that the alternative of simplicity must be true. In order to remain consistent with traditional wording, I’ll use ‘material’ and ‘immaterial’ in lieu of ‘composite’ and ‘simple’ in what follows unless the discussion is improved by using the latter. Locke attacks this reasoning in three ways: by arguing (a) that immaterial substance is as incompatible with the data of consciousness as is material substance, and (b) that matter might well have consciousness ‘superadded’ by God to a substance that seems to human reason as incapable of it (the ‘thinking matter’ hypothesis). He offers also one rather more cryptic objection, namely (c) that the Achilles (in a version offered by Thomas Burnet) could only succeed if our ‘nerves terminated in a point,’ for which I offer a speculative interpretation below. There are, in addition, at least two other Lockean positions that reject the Achilles conclusion with3

Porphyry and Proclus, see Devin Henry ‘The Neoplatonic Achilles,’ this volume. Possibly making its first appearance in Plotnius, but more likely not until John Smith. It is explicitly stated by Bayle: ‘When you warm your hand, it is certain that you feel a kind of pleasure. If at the same time there approaches your nose an agreeable odor, you feel another species of pleasure. If I ask you which of these two pleasures pleases you more, you respond “it is this one” or “it is that one,” you compare therefore together these two pleasures, and you judge them at the same time.’ Pierre Bayle, Nouvelles de la République des Lettres, Aug. 1684, VI, pp. 54–56 (reprinted in Slatkine Reprints, Genève, 1966, p. 162). 5 John Smith Select Discourses (London: W. Morden, 1660), Discourse IV, Chapter III. 4

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out attacking the Achilles reasoning. These are (d) that the very existence of an unextended substance is inconceivable, and (e) that the question of the existence of an immaterial substance is irrelevant to the issue that prompted it, namely that of personal immortality.

6.1.2 Nicholas Malebranche and Thomas Burnet Objections (a) and (b) attack the Achilles similarly. The first holds that, all other things being equal, the two disjuncts of the argument are equally absurd, while the second holds that if God’s infinite power is invoked, they are equally acceptable. The disjunctive syllogism fails in either case, and the only rational position on the nature of the soul’s substance that remains, holds Locke, is a modest agnosticism. Locke makes objection (a) in his An Examination of Père Malebranche’s Opinion of Seeing All Things in God, circa 1693, where he writes: Different sentiments are different modifications of the mind. The mind or soul that perceives is one immaterial indivisible substance. Now I see the white and black on this paper. I hear one singing in the next room, I feel the warmth of the fire I sit by, and I taste an apple I am eating, and all this at the same time. Now I ask, take ‘modification’ for what you please, can the same unextended and indivisible substance have different – nay, inconsistent and opposite (as those of white and black must be) modifications at the same time? Or must we suppose distinct parts in an indivisible substance, one for black, another for white, and another for red ideas?6

The first four sentences constitute the most common basis of an Achilles. The rhetorical questions that follow, however, are explicitly intended to deny the entailment to the Achilles conclusion. His answer seems to be that not only is the existence of an indivisible substance not entailed, it is actually incompatible with the datum it is supposed to explain. In effect, he is arguing that even if the unity we experience is incompatible with our minds being material composites, the multiplicity we experience (as unified) is equally incompatible with our minds being single immaterial simples (‘unities’), and the Achilles fails, leaving us metaphysically no wiser. A second textual source for this argument comes from the odd case of a critic of Locke’s Essay described by Noah Porter in 1887 as ‘the celebrated or rather the notorious Thomas Burnet, 1635–1715, Master of the Charterhouse and author of the “Sacred Theory of the Earth.” ’.7 As Porter recounts, Burnet wrote three critical responses to the Essay, of which only the first received a published reply, and that one contemptuously dismissive. What makes the case odd and very interesting is that while Locke gives no public response to Burnet’s criticisms, he thinks enough

6

Likely written in 1693, but not published till 1706. John Locke Locke’s Philosophical Works (London: George Bell & Sons, 1906), Vol. II, Sect. 39, p. 439. 7 Noah Porter, ‘Marginalia Locke-a-na,’ the New Englander and Yale Review (July, 1887, Vol. XI, pp. 33–40), reprinted in The Philosophy of John Locke Peter Schouls ed. (Garland: NY & London, 1984).

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of them to take the trouble to respond privately, often with some heat, in the margins of his own copy of Burnet’s pamphlet and, most important, explicitly to the Achilles. Burnet writes as follows (1699): . . . I think it unconceivable, . . ., that Matter should be capable of Cogitation,. . . . My Reasons are these; That Unity we find in our Perceptions, is such an Unity, as, in my judgment, is incompetent to Matter, by reason of the Division or Distinction of its Parts. All our Perceptions, whether of Sense, Passions, Reason, or any other Faculty, are carried to one Common Percipient, or one common Conscious Principle. For we compare them all, one with another, and censure them all, which cannot be done without one Common Judge or Percipient. Pray then tell us, what part of the Body is that, which you make the Common Percipient: Or, if that be too much, tell us how any one part of the Body may or can be so. If you say they are many; then let us know how they confer Notions, or tell one another what they have perceived in their several Districts.8

To which Locke responds: I make no part of the body so. But how any part of the body may or can be so I will undertake to tell when you shall tell how any [other] created substance [like a simple, immaterial one] may or can be so.9

His position, I think, is best summarized in this further rejoinder: Pray tell us how you conceive Cogitation in an unsolid [simple, immaterial] created substance. It is as hard, I confess, to me to be conceived in an unsolid as in a solid substance.10

This is the ‘a plague on both your alternatives’ argument, but a disjunctive syllogism can be attacked in another way, namely by denying the necessity of rejecting the ostensibly absurd alternative. Locke is famously committed to the possibility that God might by his free choice have used his divine power to superadd consciousness to matter. In his criticism of Malebranche, Locke attacks the Achilles disjunctive premise by arguing that even if attributing thought to matter leads to an absurdity, so does attributing it to immaterial substance, which blocks the inference. The thinking matter hypothesis, on the other hand, has the effect of overriding the absurdity of the matter disjunct, thus preventing the inference to the other disjunct and, once again, blocking the Achilles. This is objection (b) in my listing, but I want to add that Locke did not take full advantage of what the superaddition hypothesis offered him. The assumption of a possible divine superaddition of consciousness to matter applies necessarily mutatis mutandis to immaterial substance as well. That is, even though Locke has argued that a thinking (simple) immaterial substance is as humanly incomprehensible as a thinking (composite) material substance, if the absurdity of thinking matter can be overridden by God’s divine power, then so can the absurdity of thinking immaterial substance. This means that on the superaddition hypothesis, neither disjunct of the Achilles is rejectable by Reductio. While Locke

8 Ibid., Third Remarks p. 17. Note that Burnet seems to draw no distinction between the unity of perception and the unity of judgment. 9 Ibid. 10 Ibid., p. 48.

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does not take this final step, it is one that is completely consistent with his reasoning and one, I think, he would have embraced. With this final step in place, Locke’s argument has a pleasing symmetry. On the one hand, if we accept the authority of Reductio reasoning, then the Achilles disjunctive syllogism fails because both alternatives are equally absurd and must be rejected. On the other hand, if we reject the authority of Reductio reasoning in view of God’s infinite power, then the Achilles disjunctive syllogism fails again because the absurdity of both disjuncts is equally overridden and both are equally acceptable.

6.1.3 Unity and the Causal Theory of Perception Finally, Locke offers the following cryptic response, objection (d), to Burnet’s argument: This argument of unity if it has any force in it supposes all our perceptions of sense to be made in a point which cannot be unless all our nerves terminate in a point.11

Whatever the implicit reasoning might be here, it is at least clear that Locke intends it as a Reductio on the assumption that ‘all our perceptions [are] made in a point,’ an intriguing apparent denial of the unity of consciousness in the way in which the Achilles presumes it. Given the limits of the text, any elaboration of its reasoning is necessarily a conjecture, but, with that caveat in place, here is my own speculative reconstruction of his thinking. According to Locke’s marginal remark, we only need to posit a simple substance if we assume that ‘all our perceptions of sense [are] made in a point.’ Locke’s response to Malebranche, I think, provides the clue to what is going on here. His view is that our point of departure, consciousness, is inherently both ‘one’ and ‘many’, and in a way that is utterly unique. Because the phenomenon is unique, we have no ready vocabulary for it and thus carelessly apply terms borrowed from other contexts. Specifically, we apply words like ‘unity’, ‘simplicity’, and phrases like ‘common percipient.’ I suggest that Locke believes that these words and expressions cannot be extended to consciousness without generating paradoxical conclusions, one example of which is that consciousness winds up incompatible with both composite and simple substance. The notion of ‘unity’ that we actually understand does allow for one kind of multiplicity within a unity, for complex ideas are ‘unities’ by the action of the Understanding. The other notion of ‘unity’ is that of an indivisible. Neither of these meanings, however, capture the feature of consciousness that is supposed to fuel the Achilles. The ‘nerves’ marginal remark, I suspect, is just a further application of that thought. The ‘nerves’ remark seems to ask how the notion of unity can possibly be interpreted in order to yield the Achilles result. Clearly, it cannot be the sense of ‘unity’

11

Ibid., Marginalia, p. 45.

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in which complex ideas are unified because this unity has the mere character of a convention and, thus, does not demand a simple substance. Thus, the only other sense of the word left available is the sense of ‘indivisible’. The remark indicates that if the word is taken in this sense, the inference to a simple substance does succeed. But what could it actually mean for our diverse perceptual experience to be a such ‘unity’? For Locke, ideas are the only possible perceptions, and this means that the only meaningful assumption of the unity of consciousness is that our whole diverse experience is itself but a single indivisible idea. While this is clearly incompatible with our experience, this is not Locke’s point, it is rather that this leads to a false or absurd conclusion if we assume (as he does) the causal theory of perception. While Locke freely admits that the metaphysical detail of this causal interaction lies beyond the scope of human understanding, he does believe that what we perceive is causally determined by the configuration of matter outside us. Now, if our diverse perceptual perceptions are actually only a single point, then there must be a material cause capable of producing a single indivisible idea that contains multiple diverse perceptions. It seems to him that the only possible physical interpretation of this is that a multitude of neural streams converge on a single physical point within which they still retain their identities, and this point is then transformed into the single ideational point that contains our variegated experience. This consequence, however, must be rejected on numerous grounds. For one thing, neurologists’ investigations do not reveal any such single destination for the nerves. For another, the a priori ground of the infinite divisibility of matter prevents the existence of such a material indivisible point. For yet another, if there indeed were an indivisible material point, there could be no way in which the information converging from multiple nerves could be preserved within that point. The result of this is that Burnet’s argument is taken to fail by Locke. But what is the culprit in the failure? Did Locke simply mean to argue that we should give up the claim that consciousness is unified? I think the answer to this is both no and yes. Locke is as aware as Burnet that we judge, compare, and perceive many things at one time. He does not believe, however, that these facts entail something about the nature of human mental substance. As I mentioned earlier, he takes the question of the nature of human mental substance to lie beyond the reach of our faculties, and chooses to remain modestly agnostic on it. Yet, while he acknowledges the existence of these mental activities, he seems to be very suspicious of the use of the word ‘unity’ in the description of these mental activities, and that is perhaps because he suspects that arguments like the Achilles gain a specious plausibility because of an ambiguity and a murkiness in that and related words. We must remember that his basic position on the Achilles is that neither kind of substance is compatible with the data of consciousness, posing an apparent paradox. But paradoxes reflect the presence of concealed conceptual incoherence, and one such incoherence could exist in the misapplication of words like ‘unity’ to the unique phenomena of consciousness. That this might be the case is evidenced by the fact that even when he applies an Achilles-like argument for the immateriality of God, he shows a reluctance to specify unity as the factor in consciousness that forces the conclusion, while at the same time appealing cheerfully to sense, perception, reason, thought, and

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knowledge. Notwithstanding, it remains true that his arguments for the immateriality of God do seem to be reasonably clear applications of the Achilles, and thus they still depend on something that sense, perception, reason, thought, and knowledge have in common. What can that be if not ‘unity’? It is also true that there is ample textual evidence that the unity of consciousness plays a large role in his cognitive psychology (see below, Section 6.2.5).

6.1.4 The Remaining Two Objections Locke is generally skeptical with respect to conclusions concerning matters beyond the scope of our senses (our line is too short, we ‘cannot with it fathom all the depths of the ocean’), and so it should not surprise us if he proves to be unsympathetic to any dogmatic position on the exact nature of our substance. Like Descartes, Locke is fully convinced that each one of us knows with certainty that he himself exists, that a ‘thinking thing’ exists, but he rejects any inference from this knowledge to the nature of the thing we know to exist. We do not know and cannot know whether that thing is extended, divisible, and material or unextended, indivisible, and immaterial. Locke writes in 1690: 29. Summary. To conclude. Sensation convinces us that there are solid extended substances; and reflection, that there are thinking ones: experience assures us of the existence of such beings, and that the one hath a power to move body by impulse, the other by thought; this we cannot doubt of. Experience, I say, every moment furnishes us with the clear ideas both of the one and the other. But beyond these ideas, as received from their proper sources, our faculties will not reach. . . . [So that] we are no more able to discover wherein the ideas belonging to body consist, than those belonging to spirit. From whence it seems probable to me, that the simple ideas we receive from sensation and reflection are the boundaries of our thoughts; beyond which the mind, whatever efforts it would make, is not able to advance one jot; nor can it make any discoveries, when it would pry into the nature and hidden causes of those ideas.12

He does, it is true, allow himself to accept dualism, but he does not consider this to be ‘knowledge’, it is at best a merely ‘probable’ belief. While we do find in him at least a weak defense for the matter assumption,13 we do not even have this much for the belief in immaterial substance; and, on the contrary, he expends much effort in showing that knowing of the existence of such substance would be of little use to us. Immediately after the famous passage in which he suggests that the ‘super-addition’ of thought to matter was not to be taken as lying outside of God’s powers, he argues this in the following passage:

12

Locke E II.XXIII.29 p. 312. Locke E IV.III.16 pp. 547–548: ‘I have here instanced in the corpuscularian hypothesis, as that which is thought to go furthest in an intelligible explication of those qualities of bodies; and I fear the weakness of human understanding is scarce able to substitute another, which will afford us a fuller and clearer discovery of the necessary connexion and coexistence of the powers which are to be observed united in several sorts of them.’ 13

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I say not this, that I would any way lessen the belief of the Soul’s Immateriality: I am not here speaking of Probability, but Knowledge; and I think not only, that it becomes the Modesty of Philosophy, not to pronounce Magisterially, where we want that Evidence that can produce Knowledge; but also, that it is of use to us, to discern how far our Knowledge does reach; for the state we are at present in, not being that of Vision, we must, in many Things, content our selves with Faith and Probability: and in the present Question, about the immateriality of the Soul, if our Faculties cannot arrive at demonstrative Certainty, we need not think it strange. All the great Ends of Morality and Religion, are well enough secured, without philosophical Proofs of the Soul’s Immateriality; since it is evident that he who made us at first begin to subsist here, sensible intelligent Beings, and for several years continued us in such a state can and will restore us to the like state of Sensibility in another World and make us capable there to receive the Retribution he has designed to Men, according to their doings in this Life. {And therefore ‘tis not of such mighty necessity to determine one way or t’other, as some over zealous for, or against the Immateriality of the Soul, have been forward to make the World believe. . . . He that considers how hardly Sensation is in our Thoughts, reconcilable to extended Matter; or Existence to any thing that hath no Extension at all, will confess, that he is very far from certainly knowing what his Soul is. ’Tis a Point, which seems to me, to be put out of the reach of our Knowledge:} And he who will give himself leave to consider freely, and look into the dark and intricate part of each Hypothesis, will scarce find his Reason able to determine him fixedly for, or against the Soul’s Materiality. Since on which side soever he views it, either as an unextended Substance, or as a thinking extended Matter; the difficulty to conceive either, will, whilst either alone is in his Thoughts, drive him to the contrary side.14

In this passage, his only argument against the inference to an indivisible substance is that we are supposedly unable to conceive of something existing without extension (‘or Existence to any thing that hath no Extension at all’). This is objection (d) in my list, and it is not an argument against the Achilles per se since it is not an objection against an argument from the unity of consciousness. The fact, however, that any such inference fails is not a terrible consequence for Locke, since he sees no philosophical advantage in such knowledge in any case. While the question of what constitutes a self is central to the understanding of immortality, the existence of an immaterial substance is not. This leads him to objection (e). As I said, for Locke, any inference to inaccessible entities is inherently flawed, but even beyond that, an inference to an immaterial substance it is a wasted effort because the conclusion it seeks is useless. The point (and only point) of immortality is the rewarding of virtue and the punishment of vice, and such rewarding only makes sense if the same self-aware entity that earned the reward exists after death. But, even if the Achilles could demonstrate that the ‘rational soul’ that earns rewards must be immaterial, entailing that its substance must survive death, it does not follow that self-awareness or the same self-awareness must survive death. Soe that to prove that immortality of the soul simply because it being naturally not to be destroid by any thing it will have an eternall duration which duration may be without any perception [e.g., as in deep sleep] is to prove no other immortality of the soule then what

14 Locke E IV.III.6 pp. 541–542. My emphasis. This was already present in the 1690 edition, though the material within the curly brackets was only added in the fourth edition of 1700.

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belongs to one of Epicurus’s attoms, viz., that it perpetually exists but has noe sense either of happinesse or misery.15

Thus, proving the immortality of an immaterial substance is not equivalent to proving the immortality of the rational soul. What needs to persist is the self, and no philosophical argument can ensure this. This entails that even if the Achilles were sound, it would not provide the knowledge that we actually need. Finally, Locke’s many and ingenious arguments separating self from substance are well-known, but what follows from them concerning personal immortality should also be emphasized. Since he finds no logical connection between a ‘person’ or ‘self’, on the one hand, and any indivisible substance, on the other, it follows that knowing that our ‘substance’ persists after death would not ensure that we would have personal immortality, the kind we really want. Thus, the question of the immateriality of the soul is a serious distraction from a real issue of ultimate importance, the persistence of the self after death. This is objection (d). It is clear that whether the human mind is material or immaterial, divisible or indivisible, complex or simple is a question that, for Locke, we cannot answer. We encounter insurmountable obstacles to reason on either assumption, and so we must be content to remain modestly agnostic on this question. He says this expressly in yet another marginal reply to Burnet: If an inability to explain how any system of matter can think be an argument against a material soul, the inability to explain how body by motion can affect an immaterial being will be an argument against an immaterial soul. But such arguments raise great trophies from the ignorance of others, but think themselves safe in their own. When both sides are equally ignorant I think no advantage can be made of it on either side.16

So much for Locke’s reasons for rejecting the Achilles.

6.2 Locke, the Achilles, and God 6.2.1 John Smith’s Achilles While Locke seems to reject the Achilles as well as any of its relatives, he nonetheless allows himself a hypostasizing proof in E IV.X.10, entitled ‘Knowledge of the Existence of a GOD,’ in which he specifically argues for the immateriality of the divine mind, and on the basis of data of human consciousness. Further, the argument does have the form of a disjunctive syllogism based on the choice of material or immaterial substance; it does reject the material hypothesis where the mind of God is concerned; and it does this because matter is incompatible with certain properties of mind that are directly or intuitively available to each one of us. Yes, he argues 15

R.I. Aaron and J. Gibb, eds., An Early Draft of Locke’s Essay: Together with excerpts from his Journal (Oxford, 1936), p. 122. Cited by Mijuskovic, The Achilles of Rationalist Arguments (The Hague: Nijhoff, 1974). 16 Ibid., p. 46.

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that the eternal being we call ‘God’ must be an immaterial substance because each one of us individually senses, thinks, and knows. It is noteworthy that throughout the section, he appeals repeatedly to variants on ‘sense, perception, reason, thought, and knowledge,’ an inventory of data that all involve mental unification, but he conscientiously avoids any reference to unity. I elaborate the argument below in the following section, but for the moment it is sufficient to say that he argues from the fact that I think, that God’s mind must be immaterial! This looks very much like an Achilles argument applied mutatis mutandis to God, not man. That it is, is strongly suggested by the fact that the argument is strikingly similar to the one that John Smith (1618–1652), a Cambridge Platonist, gives for the immortality of the human soul, an argument that Smith himself sees present in the neo-Platonists, particularly Plotinus. Following Plotinus, Smith argues from the unity of perception; following Porphyry, he argues from reflective awareness; he also argues from the unity of judgment; and, in addition, he argues from the existence of a reflective self; none of these, he argues, could exist, if matter were the only substance. He gives his objectives in the introductory abstract for Discourse 4, Ch. III: The First Argument for the Immortality of the Soul. That the Soul of man is not Corporeal. . . . That Motion cannot arise from Body or Matter. Nor can the power of Sensation arise from Matter: Much less can Reason. That all Humane knowledge hath not its rise from Sense. The proper function of Sense, and that it is never deceived. An Addition of the Three Considerations for the enforcing of this first Argument, and further clearing the Immateriality of the Soul. That there is in man a Faculty which 1. controls Sense: and 2. collects and unites all the Perceptions of our several Senses. 3. That Memory and Prevision are not explicable upon the supposition of Matter and Motion.17

His abstract, however, is too modest in failing to mention his discussions of memory and ‘prevision’, which are remarkably evocative of Locke’s later doctrine of the self, but which also constitute an Achilles based on the unity present in selfhood. In effect, he argues that matter could not support self-hood because of its unification of memory and ‘prevision’ (anticipation). He writes: What Matter can thus bind up Past, Present and Future time together? which while the Soul of man doth, it seems to imitate (as far as its own finite nature will permit it to strive after an imitation of) God’s eternity: and grasping and gathering together a long Series of duration into it self, makes an essay to free it self from the-rigid laws of it, and to purchase to it self the freedome of a true Eternity. And as by its . . . Chronical and successive operations it unravels and unfolds the contexture of its own indefinite intellectual powers by degrees, so by this Memory and Prevision it recollects and twists them up all together again into it self.18

Locke seems to accept the Smith doctrine that a human self necessarily involves a unification of memory and anticipation, but not the Smith doctrine that the having of a self entails the existence of a substance that is necessarily immaterial; and, at the same time, however, he argues, on the same considerations, that an immaterial 17 18

John Smith Select Discourses (1660), Discourse IV, Chapter III, pp. 68–69. Smith, ibid. p. 83.

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substance is necessary to a divine consciousness. Mijuskovic notes that Locke had definitely read some of Smith’s writings, and that he did not accept Smith’s reasoning for the human soul’s immortality. This is quite correct, but Mijuskovic does not notice that while Locke found the Achilles inadequate to the conclusion of human immateriality, he found Smith’s arguments more than plausible when applied to God. Of course, there is one major respect in which Locke differs from Smith, he certainly does not agree ‘That all Humane knowledge hath not its rise from Sense,’ but this difference plays no role in his arguments for the immateriality of God.

6.2.2 Locke’s Arguments for the Immateriality of God The Essay contains two arguments for God’s immateriality, an initial somewhat elaborate one and a subsequent small, but clearly Achilles, one. Locke’s first argument for God’s immateriality contains two distinct sub-arguments, the first of which proves that God thinks from the fact that we think, and the second of which proves that he must, therefore, be immaterial. Only the second of these is an Achilles, and the reason it has to be preceded by the separate argument that God thinks is quite obvious. The Achilles is based on a fact that is directly available to each one of us, the fact of the unity of our own consciousnesses, which is why there is no need for a proof of that fact. Since none of us are God, however, we do not have direct access to his consciousness, and indeed, if we are intent on proving his immateriality from his consciousness, we must first prove that he is conscious, that he thinks. This is exactly what Locke does: he proves that God thinks in order to prove that he is immaterial. Since Smith is not using the Achilles to argue the immateriality of God (he is proving the immateriality, hence immortality, of our own souls), we do not find this move in his argument. Section IV.X.10 begins with an initial version of this argument, but then goes on to offer a kind of clarification or, in his word, ‘recapitulation’, that has a slightly different order. The initial argument attempts to deduce the existence of God from our knowledge of our own existence; the clarification begins with the assumption of an eternal being, and attempts to derive that being’s necessary immateriality. I will follow the order of the clarification, since it is there that Locke’s own Achilles ‘materializes’. Locke introduces his clarification with a substitution of the distinction between ‘cogitative’ and ‘incogitative’ for the traditional ‘immaterial’ and ‘material’. The device is not only not helpful, it conceals an equivocation. The argument needs two distinctions, (1) capable/incapable of thought, and (2) material/immaterial (or extended/unextended). The reason is that what is at stake is whether the property of being capable of thought can necessarily be tied either to material or to immaterial substance. I will therefore use my own two distinctions in representing his argument as follows: 1. There exists an eternal being; 2. The eternal being is the cause of human beings, entities capable of thought; 3. The eternal being is, therefore, also the cause of (human) thought;

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There are two and only two kinds of being conceivable, material and immaterial; Anything that causes thought, must itself think; The eternal being must itself be capable of thought; The eternal being cannot be material; Therefore the eternal being is immaterial (which being we call ‘God’).

Lines (1) through (6) make up the first phase of the argument, and lines (6) through (8) the second. In more detail, line (1) is supported by a version of the first-cause argument, namely that an infinite causal regress cannot exist unless it is supported by an eternal cause outside the series. Line (2): since humans are inside the series, the eternal being is also their cause; and that they think is known by reflection. Line (3) is analytic: what causes A, causes every property of A. Line (4): a metaphysical axiom. Line (5) is an expression of the principle that the cause of an effect must be of the same metaphysical type as the effect, a principle invoked also by Smith.19 Line (6) follows from line (5). And in line (7), we find the familiar Achilles rejection of materialism, the claim that thought is incompatible with matter. Near the end of the clarification in Section IV.X.10, added almost as an afterthought, we find the following small explicitly Achilles argument: . . . though our general or specifick conception of Matter makes us speak of it as one thing, yet really all Matter is not one individual thing, neither is there any such thing existing as one material Being or one single Body that we know or can conceive. And therefore if Matter were the eternal first cogitative Being, there would not be one eternal infinite cogitative Being, but an infinite number of eternal finite cogitative Beings, independent one of another, of limited force, and distinct thoughts, which could never produce that order, harmony, and beauty which is to be found in Nature.20

It is repeated two pages later, addressed to ‘materialists’: I. I would ask them, whether they imagine that all matter, every particle of matter, thinks? This, I suppose, they will scarce say; since then there would be as many eternal thinking beings as there are particles of matter, and so an infinity of gods.21

This is a separate and distinct argument against the hypothesis that God (already proven to be a cogitative being) is material. It argues that this cannot be because matter is infinitely divisible, and that therefore, consciousness would necessarily only be the property of each separate infinitesimal particle. That the argument is an

19

Smith writes: ‘Neither can those small corpuscla, which in themselves have no power of sense, ever produce it by any kind of Concourse or Motion; for so a Cause might in its production rise up above the height of its own nature and virtue; which I think every calm contemplator of Truth will judge impossible: for seeing whatsoever any Effect hath, it must needs derive from its Causes, and can receive no other tincture and imprecision then they can bestow upon it; that Signature must first be in the cause itself, which is by it derived to the Effect.’ (ibid. p. 73). Locke, on the other hand, writes: ‘. . . it is evident, that what had its being and beginning from another, must also have all that which is in and belongs to its being from another too. All the powers it has must be owing to and received from the same source.’ (E IV.X.4 p. 620). 20 Locke E IV.X.10 p. 624. 21 Ibid., p. 626.

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Achilles is supported by the fact that it is simply a reproduction of one of Plotinus’ arguments: Are we to suppose, then, that each of these parts of the soul will then perceive each [part of the sense-object] with its own parts? Or will the parts of the parts lack perceptions? But that is impossible. Yet if any and every part [of a corporeal soul] perceives the whole [sense-object], then since the dividing of a magnitude is naturally carried down to an infinite number of parts, the perceptions of a particular sense-object will also become infinite for each part, yielding an infinite number of images (eikonas) of the same thing in our ruling principle.22

The argument is an Achilles because, once again, it presumes that our perceptual experience is not of an infinitesimal pixel (as it were), but it is rather a unified whole of an infinite number of pixels. We, therefore, reject the matter hypothesis because it entails a falsehood, and we therefore are asked to accept the other disjunct, that of immateriality. Since Locke has given strong reasons for not accepting the Achilles reasoning, it is odd that we find it or something very much like it here in both his arguments for God’s immateriality. However, not all of his objections to an Achilles for the human mind apply also to his Achilles for the divine mind. For example, objections (b), (c), and (e) do not apply. As far as objection (b) is concerned, the superaddition argument entails that the human mind is not necessarily immaterial because God could have superadded thought to human matter for mysterious reasons of his own. But this argument requires the existence of a thinking God who is able to use supernatural power to make matter think. If, however, the universe consisted only of matter, there would be no thought of any kind, therefore no God, and hence no way in which divine thought could be superadded to that universe in order to make a God. Matter, having only natural powers, could not spontaneously superadd thought to itself the way a thinking God with supernatural powers could superadd it to human clay. The point is that Locke takes it as a given that divinely unaided matter cannot produce thought, and while this can be overridden for human beings, it cannot be overridden for God. If this is the case, then the Achilles is immune to the superaddition objection in the case of God. Objection (c) is the odd marginal note that the ‘unity’ argument depends on our nerves converging of a point. Since God presumably does not have a body, he also has no neural perceptual system and thus this point does not apply to him. Finally, objection (e) is that even if the immateriality of the human soul could be proven, it would be irrelevant since we are concerned to prove that the ‘rational soul,’ a personal self, is immortal, not just a ‘substance’. Since God has no material body is certainly not mortal, there is no issue of God’s immortality and this objection also does not apply to his Achilles for God. What of objections (a) and (d)? unfortunately for Locke, these are not so easily dismissed. Locke’s main objection to the human Achilles is (a), that the immaterial hypothesis is as incapable of explaining the unity of consciousness as is the material

22

Plotinus Enneads IV.7.6. Translation due to Devin Henry.

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hypothesis. His proof of the immateriality of God is still based entirely on the rejection of the material hypothesis, which implies that he is using a disjunctive syllogism to reach the conclusion of immaterialism, but this inference is blocked by the very same argument that he used against Malebranche around 1693. He infers divine thought from the existence of human thought, on the ground that only a thing with thought could cause the existence of another thing with thought. The thought in the former must presumably be similar in kind, even if not degree, to its effect. But if the human thought cannot be explained by immaterial substance, presumably that must also be true of divine thought. Yet, the argument he used in 1693 against Malebranche is still potent in 1694, the time of the Essay’s second edition. I do not see how the divine immateriality argument can withstand this objection. Locke also argues (d) when the human Achilles is in question, that the existence of an unextended substance is inconceivable, but if an unextended substance is inconceivable for the human mind, it is presumably as inconceivable for the divine mind. There seems to be no way of avoiding the conclusion that there are two incompatible lines of thought in Locke, one of which resists the Achilles inference, and one which accepts it. The five objections capture the first line, while the two arguments for God’s immateriality capture the second.

6.2.3 Locke’s Studied Avoidance of an Appeal to ‘Unity’ The problem Locke presents us is that while he repeatedly insists that ‘Sense, Thought, and Knowledge’ are incompatible with matter, he seems carefully to avoid ever telling us precisely what it is about thought that matter cannot accommodate. Like Smith, he compares the problem of accounting for consciousness to be analogous to the problem of accounting for motion, also a staple in the 17th C. theistic armament against atheistic materialism. These references to motion usually had two points to make, that motion could not account for sensation (or any of the other data of consciousness), and that even if it could, it was subject to exactly the same objection as applied to sensation, namely that matter’s essential properties could not explain its presence. Both Locke and Smith follow precisely that line of thought. In just one example, Locke writes as follows: If there were no other Being in the World, Must it not eternally remain so, a dead inactive Lump? Is it possible to conceive it can add Motion to it self, being purely Matter, or produce any thing? Matter then, by its own Strength, cannot produce in it self so much as Motion: the Motion it has, must also be from Eternity, or else be produced, and added to Matter by some other Being more powerful than Matter; Matter, as is evident, having not Power to produce Motion in it self. But let us suppose Motion eternal too; yet Matter, incogitative Matter and Motion, whatever changes it might produce of Figure and Bulk, could never produce Thought: Knowledge will still be as far beyond the Power of Motion and Matter to produce, as Matter is beyond the Power of nothing, or nonentity to produce.23

23

E IV.X.10 p. 623.

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While Smith had written, after granting motion to basic particles for the sake of argument: But yet though we should grant all this which Lucretius contends for, how shall we force up these particles of Matter into any true and real Perceptions, and make them perceive their own or others motions, which he calls Motus sensiferi? For he having first laid down his Principles of all Being, as he supposeth, (neither is he willing to leave his Deities themselves out of the number) he only requires these Postulata to enfold the nature of all by, Concursus, motus, ordo, positura, figure. But how any such thing as sensation, or much less Reason, should spring out of this barren soil, how well till’d soever, no composed mind can imagine. For indeed that infinite variety which is in the Magnitude of parts, their Positions, Figures and Motions, may easily, and indeed must needs, produce an infinite variety of Phenomena, which the Epicurean philosophy calls Eventa. And accordingly where there is a Sentient Faculty, it may receive the greatest variety of Impressions from them, by which the Perceptions, which are the immediate result of a Knowing faculty, will be dsftinguish’d: Yet cannot the Power it self of Sensation arise from them, no more then Vision can rife out of a Glasse, whereby it should be able to perceive these Idola that paint themselves upon it, though it were never so exactly polish’d, and they much finer and exacter than they can be.24

Yet, for all this, and many more examples of the same strong conviction, Locke is wary of telling us what it is about thought that requires an immaterial substance. Is it because thought is only possible where there is a unity of consciousness and Locke is aware that he has already dismissed this as an argument for immateriality? This is admittedly no more than a speculation, but that thought essentially and necessarily involves unification for Locke is textually defensible.

6.2.4 Locke, ‘Sense, Thought, and Knowledge,’ and Unity The question before us is this: Does Locke accept the Achilles inference for God’s immateriality? The answer to this question hinges on the answers to two subquestions: (1) Does Locke agree that consciousness presents a number of unifications that matter cannot account for? and (2) If he does, does he infer the immateriality of God from the fact of those unifications? The answer to the first question is a resounding, Yes, but a yes that is quite complex. The key to most of Locke’s thinking with respect to mind is that he makes self-awareness its defining characteristic. Self-awareness crops up in his account of perception, his account of the self, in his account of judgment and reasoning, and in his theory of reasoning, sometimes explicitly, sometimes not. It is no accident that when he is arguing for God’s immateriality, he appeals again and again, as noted earlier, to ‘sense, perception, reason, thought, and knowledge,’ for all of these presuppose self-awareness, and self-awareness is what makes unity possible in the mind. It is worth noting, once again, that self-awareness played a central role in Smith’s thinking as well. In rough terms, here is the path that Locke follows as I see it.

24

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There is no unity for him in the corpuscular world as far as aggregates are concerned. Unity for aggregates is only brought into existence by perception, whose unified perceptual objects are complex ideas – his term for this unity is ‘coexistence’.25 Corpuscles might exist at one and the same time, but only the simple constituents of a complex idea ‘co-exist’: this is a technical term, and ‘to coexist’ is to ‘co-exist for’ a perceiver. Thus, the perception of all complex ideas implicitly requires self-awareness. The apprehension of Ideas of Reflection, however, explicitly requires the ability of the mind to treat itself as an object of scrutiny. While perceptual objects require self-awareness for their unity, Locke is explicit that the world in which those objects appear, the world of the self, is also based on selfawareness. Since unity exists only where there is a representation for a perceiver, the only way in which a perceiver can become unified as a self is through becoming a representation to itself. He writes: . . . to find wherein personal identity consists, we must consider what person stands for – which, I think, is a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places; which it does only by that consciousness which is inseparable from thinking, and, as it seems to me, essential to it: it being impossible for any one to perceive without perceiving that he does perceive. When we see, hear, smell, taste, feel, meditate, or will anything, we know that we do so.26

This passage serves to confirm that he considers reflection to be as essential to perception as it is to self-hood. Finally, the possibility of judgment and reason also presuppose self-awareness. The reason for this is intuitively quite clear. For Locke, all reasoning reduces to the comparison of ideas: . . . all the inquiries we can make concerning any of our ideas, all that we know or can affirm concerning any of them, is, That it is, or is not, the same with some other; that it does or does not always coexist with some other idea in the same subject; that it has this or that relation with some other idea; or that it has a real existence without the mind. Thus, ‘blue is not yellow,’ is of identity. ‘Two triangles upon equal bases between two parallels are equal,’ is of relation. ‘Iron is susceptible of magnetical impressions,’ is of co-existence. ‘God is,’ is of real existence.27

But a ‘comparison’ that yields judgments of agreement or disagreement necessarily presupposes a judger for whom the terms of the comparison are present. Smith had already made this point and Mijuskovic cites him as follows:

25

For example, ‘6. Of their necessary co-existence in substances. Thirdly, The third sort of agreement or disagreement to be found in our ideas, which the perception of the mind is employed about, is co-existence or non-co-existence in the same subject; and this belongs particularly to substances. Thus when we pronounce concerning gold, that it is fixed, our knowledge of this truth amounts to no more but this, that fixedness, or a power to remain in the fire unconsumed, is an idea that always accompanies and is joined with that particular sort of yellowness, weight, fusibility, malleableness, and solubility in aqua regia, which make our complex idea signified by the word gold.’ 26 Locke E II.XXVII.9 p. 335. My emphasis. 27 Locke E IV.I.7 p. 527.

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We also find such a faculty within our own souls as collects and unifies all the perceptions of our several senses, and is able to compare them together; something in which they all meet as in one centre: which [a footnote reference to Enneads, IV.7.6 is given] Plotinus hath well expressed . . . That in which all those several sensations meet as so many lines drawn from several points in the circumference, and which comprehends them all, must needs be one. For should that be various and consisting of several parts, which thus receive all these various impressions then must the sentence and judgment passed upon them be various too.28

In addition, writes Smith: . . . no sense can judge another’s objects, nor convince it of any mistake, . . . If therefore there be any such thing within us a controls our Senses, as all know there is; then must that of an Higher nature then our Senses are.29

The answer to our first question is that Locke indeed does believe that the mind presents a number of unifications that matter is unable to account for. Our second question was whether Locke infers God’s immateriality from the fact of these unifications. Again, I believe the answer is, Yes. When Locke argues his case, he argues it from the presence of ‘sense, perception, reason, thought, and knowledge.’ He believes that precisely these aspects of the mind cannot be explained by matter. But the factor that is present in all of these aspects is precisely that of mental unification, a unification that is made possible by a property that matter cannot have, the property of selfawareness. Again, this is a point argued by Smith (who cites Porphyry approvingly): For that which we call Sensation, is not the Motion or Impression which one Body makes upon another, but a Recognition of that Motion; and therefore to attribute that to a Body, is to make a Body privy to its own acts and passions, to act upon itself, and to have true and proper self-feeling virtue; which Porphyrie hath elegantly expressed . . . In the sensations of living creatures the soul moves, as if unbodied Harmony her self should play upon an instrument, and smartly touch the well-tuned strings: but the Body is like that Harmony which dwells inseparably in the strings themselves which no perception of it.30

6.2.5 Conclusion The preceding considerations persuade me that Locke, on the one hand, is deeply resistant to both the Achilles inference and the Achilles conclusion where the human mind is concerned, and, on the other, that he confidently deploys two Achilles arguments in proving the necessary immateriality of the divine mind. As to why he would have used the argument for God’s immateriality, but not for man’s, I cannot say.

28

Op. cit. My emphasis. Smith ibid., p. 77. 30 Ibid., p. 76. 29

Chapter 7

The Reverse Achilles in Locke Further to Part I of Schachter’s ‘Locke and the Achilles Argument’ Benjamin Hill

Voltaire in his encomium to Locke singled out his analysis of soul and the suggestion that matter might think as Locke’s greatest philosophical accomplishment. This was of course to highlight Locke’s role in the thinking matter debate and the budding materialism of the French philosophes.1 If Jean-Pierre Schachter’s assessment of Locke’s criticisms of the Achilles argument (as applied to humans) is correct, Voltaire’s praise is rather misplaced. For according to Schachter, Locke’s moral is that modest agnosticism is the only rational position we can take regarding the nature of the soul: ‘It is clear that whether the human mind is material or immaterial, divisible or indivisible, complex or simple is a question that, for Locke, we cannot answer. We must encounter insurmountable obstacles to reason on either assumption, and so we must be content to remain modestly agnostic on this question.’2 While it is quite true that Locke never stated that the mind is material, or ever

B. Hill Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 80143, Fax: (519) 661-3922 e-mail: [email protected] 1 See John Yolton, Thinking Matter: Materialism in Eighteenth-century Britain (Minneapolis: University of Minnesota Press, 1983) and idem, Locke and French Materialism (Oxford: Clarendon Press, 1991). 2 Jean-Pierre Schachter, ‘Locke and the Achilles Argument,’ supra. See also: ‘Objections (a) and (b) attack the Achilles similarly. The first holds that, all other things being equal, the two disjuncts of the argument are equally absurd, while the second holds that if God’s infinite power is invoked, they are equally acceptable. The disjunctive syllogism fails in either case, and the only rational position on the nature of the soul’s substance that remains, holds Locke, is a modest agnosticism.’ Schachter bolsters his claim with a quotation from Locke’s marginalia on Burnet’s pamphlet: ‘If an inability to explain how any system of matter can think be an argument against a material soul, the inability to explain how body by motion can affect an immaterial being will be an argument against an immaterial soul. But such arguments raise great trophies from the ignorance of others, but think themselves safe in their own. When both sides are equally ignorant I think no advantage can be made of it on either side.’ This passage is not as univocal as Schachter presumes, however. The

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propounded an explicitly materialist argument, or ever abandoned dualism (indeed, his official position always was that dualism is ‘the more probable opinion’), the issue here concerns the internal logic of Locke’s criticism of the Achilles. That is to say, the issue is whether Locke ought to have accepted some version of materialism, whether, on the principles Locke laid down, it would be rational for one to be a materialist rather than merely agnostic. Pace Schachter, I believe that Locke ought to have accepted some version of non-reductive, emergentist materialism. Indeed, I believe that Locke was working in that direction in the Examination of P. Malebranche’s Opinion of Seeing All Things in God insofar as he was defending the central premise of the Reverse Achilles argument and even developing qualified, though complete, versions of the Reverse Achilles. The difference between Schachter and me centers around different assessments of Locke’s objections a–c (to retain Schachter’s categorization), but it really focuses on different understandings of objection (a).3 In the interplay between objections (a) and (b), Schachter sees Locke developing an antinomy. Reductio reasoning tells us to accept the unity-simplicity and diversity-compound conceptual relationships and thus view both disjuncts in the Achilles syllogism as equally absurd while speculation about the possibilities of omnipotence tells us to accept that both disjuncts are equally acceptable. I see things differently in that I see the suggestion that God might superadd thought to matter as a rejection of the necessity of the connection between true unity and simplicity, which entails that the way has been cleared for rejecting the simplicity disjunct without also denying that thought can exhibit some sort of genuine unity.4 The rejection of this unity-simplicity relationship, by loosening or changing the sorts of metaphysical unity available to be applied to the phenomenological unity of thought, was necessary for the development of the idea that thought as we experience it, i.e. as unified in a single perceiver’s experience, might nonetheless be composite, which is the key premise in the Reverse Achilles. So, here, I will show that Locke accepted this key premise, that composites can be single representations or thoughts of individual thinkers, and even that he deployed a limited, yet complete, version of the Reverse Achilles as a way of showing that Locke was developing the conceptual resources to move beyond a merely modest and pious agnosticism with regard to the mind toward an actual materialism. Thus I will show that Voltaire was closer to the truth regarding Locke’s position than Schachter is.

basis for an alternative reading should become clear from the alternative interpretation sketched below. Note here, however, that Locke’s complaint is an ad hominem directed against those who reject the materialist disjunct on the basis of our ignorance of the mechanics of the material mind, as Burnet did, rather than a direct statement that materialism is an irrational position. 3 Objection (a) is characterized by Schachter as, ‘that immaterial substance is an incompatible with the data of consciousness as material substance,’ (p. 2). I don’t see Locke as accepting that material substance is incompatible with the ‘data of consciousness’ since, as I see it, Locke was reconceptualizing the notions of unity and diversity such that the felt unity of consciousness could be accepted as nevertheless compatible with materialism. 4 An article such as this is not the proper place to hash out all the details of that understanding of Lockean superaddition.

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The Reverse Achilles is simply the Achilles turned on its head. Whereas the Achilles is an argument for the simplicity and immateriality of mind based on the unity of consciousness or thought, the Reverse Achilles is an argument for the complexity and materiality of mind based on the disunity and compositionality of thought. The Reverse Achilles can be schematized as follows: RP0: Substances are either simple and immaterial or composite and material. RP1: Human thoughts or representations are truly disjointed and composite. RP2: No simple, partless substance can contain truly disjointed and composite representations or thoughts. RC1: Therefore, the human mind cannot be simple, partless, and immaterial. RC2: Therefore, the human mind must be material.

Locke never stitched together an argument quite like this, but he did possess all the parts to do so. For example, Locke’s mental atomism or compositionalism is quite well known, and RP2 is defended in his critique of Malebranche. Let’s briefly consider that defense. Locke latches onto Malebranche’s claim that ‘the ideas He [God] had of the world are not different from Himself, so that all creatures, even the most material and terrestrial, are in God, though in a completely spiritual way’5 in order to reduce to absurdity Malebranche’s doctrine that all things are seen in God. Given the standard theological assumption that God is a simple substance, Malebranche’s doctrine amounts to the absurd claim, says Locke, that ‘a simplicity [is] made up of variety.’ The problem here is a conceptual one involving the distinctness of God’s various ideas. ‘They are,’ says Locke, ‘actually distinct, or else we could not see them distinct in Him.’ How, then, could such distinct beings be in God – only as ‘either parts, or modifications of the Deity, or comprehended in Him as things in a place.’6 Locke does not come out and say it, but we are supposed to readily see that each of these alternatives requires complexity on God’s part. If ideas x and y are distinguished by being different parts of God’s mind, God would have as many parts as there are distinct ideas, and so could not be a simple substance. If x and y are distinguished by being located in parts A and B of God’s mind, God’s mind would have parts, would be extended, and would be material. The less obvious alternative is the one involving modifications, for it does not seem absurd to maintain that distinct modifications may simultaneously occupy the same point, as when solidity and shape are said to simultaneously inhere in the same place. Maneuvers like this cannot suffice, however. For, as Locke points out a few pages later, not all modifications are compatible in the way solidity and shape are. Many ideas, understood as modifications, are ‘inconsistent and opposite,’ e.g., black and white, hot and cold, round and square, etc., and would cancel each other out, on pain of contradiction, were they ever placed together in a single simple space or substance. Thus God, or

5

Nicholas Malebranche, The Search after Truth, ed. Thomas Lennon and Paul Olscamp, (Cambridge: Cambridge University Press, 1997), III.ii.5, 229. 6 John Locke, Examination of Malebranche, in The Works of John Locke (London, 1823) 9:229.

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at least the human mind, would after all need to have different parts for each of the contrary sensations to modify.7 Locke went a little bit farther, however, and gave what appears to be a version of the Reverse Achilles restricted to sensory perception.8 Against the Peripatetic doctrine of sensible species Malebranche had argued that ‘a great number of objects located in the sky and on earth can be seen from the same place or the same point; the species of all these objects would then have to be capable of being reduced to a point,’ which is impossible; therefore sensory perception cannot be mediated by gross, sensible species.9 Locke jumps on the claim that sensory perception, at least in the visual case, requires reduction to a point. As a matter of fact, Locke argues, visual perception is impossible if it terminates in a single point: ‘the bottom of the eye or retina, which, in regard of these rays, is the place of vision, is far from being a point. Nor is it true, that though the eye be in any one place, yet that the sight is performed in one point, i.e. that the rays that bring those visible species do all meet in a point; for they cause their distinct sensations, by striking on distinct parts of the retina, as is plain in optics; and the figure they paint there must be of some considerable bigness.’10 Whether one was speaking of sensible species or particles of light didn’t really matter in Locke’s eyes, the point is the same: visual perception requires ‘some considerable bigness.’ The reason for this is quite similar to what we’ve just seen with regard to diversity and distinctness among the ideas in God’s simple mind – to perceive diverse and distinct parts of physical objects requires that the particles of light reflecting off of

Fig. 7.1 From Descartes, The World

7 ‘Take “modification” for what you please, can the same unextended indivisible substance have different, nay inconsistent and opposite (as these of white and black must be) modifications at the same time? Or must we suppose distinct parts in an indivisible substance, one for black, another for white, and another for red ideas, and so of the rest of those infinite sensations which we have in sorts and degrees; all which we can distinctly perceive, and so are distinct ideas, some whereof are opposite, as heat and cold, which yet a man may feel at the same time?’ (Ibid., 234–235). 8 Cf. with Schachter’s discussion of Burnet and objection (c), pp. 4–5. 9 Malebranche, Search, III.ii.2, 220–221. 10 Locke, Examination, 216.

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those parts strike the parts of the eye (and thence the brain) in a way that preserves the object’s original ‘ratios’. Failure to preserve these ‘ratios’ results in the very least in a distorted perception, and in an absolutely inchoate jumbled perception if all the particles of light strike in the very same spot. Consider Descartes’ famous Fig. 29 from The World (Fig. 7.1). If the light reflected from the arrow’s head and the light reflected from its fletching strike the same spot on the retina as the light reflected from its shaft, only optic nerves 4 will be agitated, and then only point b on the ‘internal surface of the brain’ would be inscribed. How would the mind perceive that inscription as an arrow pointing toward the perceiver’s left instead of as an arrow pointing toward her right, or as a small point-like blob, or as any other possible object of sensation? The mind could not do so on its own, since it could not possibly consider the infinite possibilities that inscription represents and neither would it have any reason for favoring any one over all the others. Thus sensory perception would require incessant, standing miracles, the miracle of dividing identical motions in the brain into endlessly diverse and distinct sensations and sensory perceptions, and presumably always on principled grounds. As with the problem of God’s simplicity, however, Locke ultimately opted for mysterianism: ‘But when by this means an image is made on the retina, how we see it, I conceive no more than when I am told we see it in God. How we see it, is, I confess, what I understand not in the one or in the other, only it appears to me more difficult to conceive a distinct visible image in the uniform invariable essence of God, than in variously modifiable matter; but the manner how I see either, still escapes my comprehension.’11 As we all can see, however, it’s as short of a step from God’s mind and God’s simplicity to sensory perception and then the human mind and its simplicity as it is from the acceptance of mysterianism to the irrationality of immaterialism and then the rationality of materialism. And as Voltaire emphasized, those willing to take that small step, like La Mettrie,12 were not long in coming.

11

Ibid., 217. See also 254. In La Mettrie all human thought was imagination and the imagination was the interior part of the brain where figures were literally traced onto it (the medullary screen): ‘I believe that everything is imagined and that all the parts of the soul can be properly reduced to imagination alone, which forms them all, and thus that judgment, reason, and memory are only parts of the soul which are in no way absolute but are veritable modifications of that sort of medullary screen on which the objects painted in the eye are projected as in a magic lantern. But if such is the wonderful and incomprehensible result of the organization of the brain, if everything is conceived by the imagination, if everything is explained by it, then why divide up the sensitive principle which thinks in man? Surely this constitutes a manifest contradiction for the supporters of the mind’s simple nature? For something that is divided can no longer, without absurdity, be seen as indivisible. See where we are led by the abuse of language and the haphazard use of grand words like “spirituality” and “immateriality” etc . . .’ (Julien Offray de la Mettrie, Machine Man, in Machine Man and Other Writings, trans. Ann Thomson [Cambridge: Cambridge University Press, 1996], 14–15). 12

Chapter 8

Cudworth and Bayle: An Odd Couple? Thomas M. Lennon

At the end of the seventeenth century, two of the most important authors dealing with the Achilles are Ralph Cudworth (1617–88) and Pierre Bayle (1647–1706). From our temporal perspective, the importance of Cudworth looks backward in time. Directly or through John Smith, he recovers and prominently deploys the ancient texts in which the Achilles was first expressed. Bayle’s importance is forwardlooking. For his citation of the Achilles is another instance in which Bayle was the ‘arsenal of the Enlightenment.’ He was a source for it on which Hume almost certainly drew, but perhaps also Mendelssohn, and, more likely, Kant who probably even gets his designation of ‘Achilles’ from Bayle. Cudworth and Bayle are independently important, but there might also be a connection between them (even if, in the end, Bayle himself might not deploy even the narrow Achilles, while Cudworth favors the Broad Achilles). Bayle was no mean scholar of ancient texts, and he is usually very fastidious about citing his sources. In the case of the Achilles, however, his citations seem insufficient to account for the argument he deploys. It is interesting to speculate on Cudworth as his source, especially since in any case Cudworth’s texts illuminate Bayle’s. On the face of it, Cudworth and Bayle seem an unlikely pairing. Certainly, they are polar opposites in outlook and style. The Cambridge Platonist is a dogmatic metaphysician, flamboyantly baroque in expressing the most speculative and idiosyncratic of views. By contrast, the Huguenot refugee is a positivist skeptic, a cynical pessimist, stylistically direct and brutal, yet delighting in the homeliest of anecdotes, even obscene ones, to make his philosophical points. Bayle once said that there are two kinds of philosopher, journalists, who tell it like it is, and lawyers, who relentlessly pursue a cause. Bayle himself is a journalist, especially but not only in the Dictionary, where his self-assigned reportorial role of faithfully conveying the views of others with their greatest cogency generally leaves his own position difficult to discern. On the other side, there is little T.M. Lennon Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 85751, Fax: (519) 661-3922 e-mail: [email protected]

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doubt but that Cudworth is a lawyer. His cause is clear from beginning to end, and everything he says is part of the case for it. Nowhere is the dispassionate weighing of evidence sic et non that confounds and delights readers of Bayle. Instead, Cudworth advances his views as the truth, the whole truth, and nothing but the truth. Even so, there are a striking number of remarkable convergences between them, beyond the appearance of the Achilles in their work. Initially striking is the bracketed appearance of the argument, limited to a highly contextualized harassment of atomism. It occurs in Cudworth’s great work, the True Intellectual System of the Universe (1678),1 where he prefaces his deployment of it with the following disclaimer: his aim is only to show how certain ancients were led to the unlikely view espousing unextended substance and how that view might be best used against materialism without necessarily embracing the view himself. He purports to show how they came ‘to assert and maintain a thing so repugnant to Sense and Imagination, and consequently to all Vulgar Apprehension, as a Substance in it self Unextended . . .Wherein we shall only represent the Sense of these Ancient Incorporealists, so far as we can, to the best advantage, in order to their Vindication, against Atheists and Materialists; ourselves in the Mean time, not asserting any thing; but leaving every one that can, to make his own Judgment; and so either to close with this, or that other Hypothesis, of Extended Incorporeals. (822)’ Now, despite Cudworth’s failure to commit himself on the extendedness of all things, he does embrace a clear conclusion: not everything is corporeal. As lawyers today put it, he argues in the alternative, drawing the same conclusion from what are incompatible premises.2 The soul is unextended, therefore it is immaterial; the soul is extended, therefore it is immaterial. The bracketing of interest occurs because the Achilles is primarily deployed only to support the first alternative. Of this, more below. Bayle, too, inserts the argument into a hypothetical context. In his Dictionary entry on Leucippus, he wonders at the failure of this ancient author and his atomist followers to regard each atom as endowed with a vital principle, a supposition that ‘would have enabled them to solve some of the objections that have been made against their theory.’3 To begin with, he remarks, they would have been able to respond to the sort of worries expressed by Plutarch and Galen over life as (what 1

Reprinted in a photo-offset edition, 2 vols., (New York: Garland Publishing, 1978). All citations are made from this work with great care, thus obviating the need for the sic device, whose perforce repeated use would have been annoying. 2 ‘My client did not borrow the lawnmower, therefore need not make restitution; my client borrowed the lawnmower but returned it, therefore. . . .’ 3 First edition, 1696; second edition, which alone contains this text, 1701. All citations are made from the translation of Pierre Desmaizeaux, 1734–37, carefully verified against the French text. Reprinted in a photo-offset edition, 5 vols., (New York: Garland Publishing, 1978). This translation is used because its language itself is important. Hume, for example, took his description of Spinoza’s monism from Bayle, but clearly in Desmaizeax’s translation: ‘the hideous hypothesis.’ (Not incidentally, this phrase occurs in the text in which Hume discusses the Achilles argument. The Treatise of Human Nature, 1.4.5.) Cross-referencing editions of the Dictionary is in any case easy, by article and remark.

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we would call) an emergent property. One does not get blood from a stone, but not life and thought, either. In addition, they would have had found ‘another great advantage,’ viz. ‘some answers’ to an ‘unsurmountable objection,’ which turns out to be, at least in part, the Achilles. But as in the case of Cudworth, there is little doubt about Bayle’s own rejection of materialism, since, however much the hypothesis of animate atoms might rebut the Achilles, in the end he thinks that there are arguments, from Augustine and others, that cannot be rebutted. The bracketing of the Achilles means that the strongest conclusion drawn from it by these two authors is the ontologically negative one that whatever it is, the soul or mind is not something material. Bayle’s summary statement is that ‘thought is incompatible with a compound being,’ Cudworth’s conclusion, as has been seen, is that whether it is extended or not, the mind is not something corporeal. Thus, neither deployment of the argument qualifies as an Achilles in the strict and narrow sense of Kant. Indeed, there are more than a few intimations, to be seen below, that it goes no farther than Kant’s own cooptation of the argument in terms of the ‘I think’ that must accompany all representation. Both Cudworth and Bayle rehearse the argument as derived from and directed against ancient authors, but it is clear in both cases, at least with a bit of context in Bayle’s, that the contemporary scene was no less the concern than the ancient. Atomism had never lost its association with hedonism, tychism (and thus the denial of Providence), materialism and the denial of the soul’s immortality. Concurrent with the general reliance of the 17th-century New Science on atomism, these threats to orthodoxy were evident in a way unmatched since antiquity. Thus the efforts of Gassendi to ‘baptize’ Epicurus with certain key modifications to his system. Moreover, there were versions of atomism proliferating far beyond Gassendi’s friendly amendments to it. Even Descartes was widely read as an atomist such that no less than Boyle was able to refer to him and the Gassendists in the same breath as ‘corpuscularian,’ the term that Locke applied to his own views. Cordemoy argued that Descartes’s own principles led to atomism of a metaphysical sort, and not just for instrumental purposes in doing physics. The ambiguity of the relation in Locke between atoms and substance points to the resolution of the issue in terms of the phenomenal atomism of Berkeley and Hume. Nor should it be altogether surprising if the handling of the Achilles by both Bayle and Cudworth should anticipate the metaphysical atomism, or monadology, of Leibniz.4

4 On Gassendi, see Margaret J. Osler, ‘Baptizing Epicurean Atomism: Pierre Gassendi on the Immortality of the Soul,’ in Margaret J. Osler and Paul Lawrence Farber, eds. Religion, Science and Worldview (Cambridge: Cambridge University Press, 1985) 163–83. On Cordemoy’s atomism, see Fred Ablondi, Gerauld de Cordemoy: Atomist, Occasionalist, Cartesian (Milwaukee: Marquette University Press, 2005) Ch. 2. On the anticipation of Leibniz, see Jean-Pierre Schachter, ‘Pierre Bayle, Matter, and the Unity of Consciousness,’ Canadian Journal of Philosophy 32 (2002) 255; Thomas M. Lennon, ‘Bayle and Late Seventeenth-century Thought,’ in Psyche and Soma, ed. J. P. Wright & P. Potter (Oxford: Clarendon Press, 2000) 204–07; Gianluca Mori, Bayle: philosophe (Paris: Honoré Champion, 1999) 131–32.

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Finally, and perhaps most surprisingly, the tradition on which Cudworth and Bayle draw for the Achilles turns out to be the same. That a Cambridge Platonist should look directly to the texts of Plotinus, Proclus et al., is certainly no surprise. The only source that Bayle mentions, aside from a passing illustration taken from Maimonides, is François Lamy’s De la connoissance de soi-même, which, however much it might be related to what Bayle has to say in the article, in fact does not contain the Achilles. Instead, his likely source for it is one that, as will be seen in the end, connects him in a surprising way with Cudworth.

8.1 Cudworth Cudworth’s ultimate aim was a system of ethics, an area which he saw as threatened by fatalism of various sorts. His ‘true intellectual system of the world’ was originally planned for three parts, each directed against what he saw as a form of fatalism. Only the first part, directed against ‘mechanical atomical fate,’ ever appeared. The second part was to combat ‘pantheistic stoical fate,’ and the third, ‘theological Calvinist fate.’ The third part would have opposed him to Bayle, who as a Huguenot was nominally a Calvinist, and for whom the doctrine of strict predestination, although far from being the center piece of his work, is nonetheless characteristic of his outlook.5 Cudworth sees two great advantages to the atomist philosophy: ‘it renders the Corporeal World Intelligible to us, since Mechanism is a thing that we can clearly understand, and we cannot clearly and distinctly conceive any thing in Bodies else . . .and it prepares an easie and clear way for the Demonstration of Incorporeal Substances, by setling a Distinct Notion of Body’ (48–49). Historically, however, atomism had been corrupted in the tradition between Democritus and Hobbes by an adherence to corporealism, the view that all that exists is body or matter, which results in atheism (59). For all he might claim about the intelligibility of the corporeal world wrought by atomism, however, there is an insoluble inconsistency in Cudworth’s own conception of matter. For at the same time that he purports to subscribe to (uncorrupted) atomism, he also takes matter to be infinitely divisible (829–30) and even to be identical to space.6 The infinite divisibility of matter and its identity with space, which eliminates the void, are precisely the points on which Descartes distinguished his view from atomism. Indeed, as J.-P. Schachter argues elsewhere in this volume, Leibniz claimed that matter cannot exist at all because of its infinite divisibility. In any case, the significance of materialism is clear. Mainly appealing to the authority of Plato and Aristotle, Cudworth concludes: ‘though all Corporealists be not therefore of necessity Atheists; yet Atheists universally have been Corporealists, this being their First and Grand Postulatum, that there is no other Substance besides

5 Lydia Gysi, Platonism and Cartesianism in the Philosophy of Ralph Cudworth (Bern: Herbert Lang, 1962) 1, 111. 6 Gysi, 3.

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Body’(768). Cudworth’s argument of real interest is to show this necessary condition for atheism to be false by showing that the human soul is incorporeal. This he does principally by appeal to the Achilles as the main part of his rebuttal of the atomist argument for materialism. Here is that argument: (1) Whatever exists is extended. (2) Whatever is extended is body. Therefore, (3) Whatever exists is body, i.e. nothing is incorporeal.

There are two (incompatible) incorporealist positions. Each position denies one of the premises, but accepts the other.7 One position, argued for at great length throughout the texts discussed below, is that while all extended things are corporeal, there exist non-extended things that are ipso facto incorporeal. It is here that Cudworth deploys the Achilles. The other position is that while everything is extended, there are some things that are incorporeal. It receives very scant attention at the end and is defended only to the extent that the defense of the first position shows the materialist conclusion to be false. Cudworth’s interest is only in what the two positions share, viz. that there exists a substance that is not material.8 But if so, i.e. if it is really left open to all to choose their version of incorporealism, then he takes the Achilles to be inconclusive and cannot be advancing it unconditionally as his own argument, or part of it, against incorporealism. The Achilles can be deployed only on condition that the incorporeal substances doing the unifying are unextended, and Cudworth never argues that this condition is satisfied; on the contrary, he explicitly leaves open the possibility that it is not. Another possibility, of course, is that the Achilles is supposed to support the second position as well. Cudworth gives no indication that his argument for the first position can be extended to the second, but this possibility will be touched upon at the end below. Both the atomists and their incorporealist opponents holding the first option are taken to agree in the assumption that there is only one kind of extension, viz. corporeal extension, which is to say that it has size and parts outside of parts. Anything extended in this sense is divisible (or ‘discerpible,’ as the Cambridge Platonists style it), ‘not only Intellectually and Logically, but also Really and Physically’ (822). In addition, any such extended thing will also be impenetrable by any other such impenetrable thing. Here, Cudworth draws on Descartes’s criterion for ontological independence, or existibility apart, viz. conceivability apart. The thrust of the rebuttal is to show by various considerations more or less approximating the Achilles that not everything is extended, thereby upsetting the atomist conclusion that nothing is incorporeal. 7

A consistent position is to deny both premises: there are some unextended things, and some extended things that are incorporeal. No one held this view, however, for one or the other of the categories would be idle, at least in accounting for the phenomena under discussion here. 8 ‘Our selves would not be Understood here, Dogmatically to Assert any thing in this Point, save only what all Incorporealists do agree in: To wit, That besides Body, which is Impenetrably and Divisibly Extended, there is in Nature another Substance, that is both Penetrable of Body and Indiscerpible; or which doth not Consist, of Parts Separable from one another. That there is at least, such a Substance as this, is unquestionably manifest, from what hath been already declared’ (834).

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His actual presentation of the argument, or arguments, is unexceptional, for he essentially just quotes them from his classical sources, in the original language followed by his translation, usually with only straightforward commentary. He begins by drawing attention to Simplicius’s Proclean argument from self-reflection. ‘Whatsoever can Act and Reflect upon its whole Self, cannot possibly be Extended, nor have Parts Distant from one another’ (823). This very condensed statement of the Proclean argument, set out by Devin Henry elsewhere in this volume, is nowhere developed by Cudworth; but it nonetheless enters incidentally and allusively in the context of his Plotinian version of the Achilles. For example, following Plotinus, that if the soul were extended, then like its object it would divided, such that one part of it would perceive one part of the object, another another part, and so on. ‘Whereas it is plain by our Internal Sense, That it is One and the Self same ting in us, which perceives, both the Parts and the Whole’ (825). Or still later, ‘nor indeed is it otherwise conceivable, how a whole Quantity of Extended Substance should be One thing, and One Personality, one I My Self in it all, were there not One Indivisible thing, Presiding over it, which Held it all together, and Diffused it self thorough all. And thus do we see, how this Whole in the Whole and in every Part (do what men what they can) will like a Ghost still haunt them, and follow them every where’ (831). Cudworth’s main Achilles, however, is the Plotinian version and his source for it is Plotinus himself.9 He begins the argument with the following mereological dilemma: if every part of a soul is not a soul, then the resulting soul comes from nothing. Yet ‘Nothing can (Causally) come from Nothing’ (823). (In particular, the proponents of atomism reject emergent properties for a reason of special interest here that was later pointed out by Bayle: if there were emergent properties of any sort, then immortality might emerge along with thought from atoms suitably configured.) But if every part of the soul is soul, then all parts but one would be superfluous. Moreover, ‘every supposed Part thereof, would be the same with the Whole,’ and therefore would not really be a part, which can never be the same with the whole. (824) And without parts, the soul would not be extended. The condition for identity expressed in the second horn is functional: two things are identical if they have the same function. Thus, if each putative part of the whole soul were soul, i.e. if each were capable of thought, sense, etc., they would be the same with it and thus would not be parts at all. On the other hand, if the soul were extended but without parts, this argument does not apply. Again, such a view will be touched upon at the end below. Cudworth next conveys three more or less close versions of the Achilles. The first also comes from Plotinus. If the soul were extended and thus had parts, then either (1) each of its parts perceives only a part of the object (but this cannot be, for ‘Internal Sense’ shows that there is but one thing in us that knows both parts and the whole of the object); or (2) each part perceives the whole (but then there are

9

Enneads, 4.7.2.

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infinitely many perceptions in us of the same object—again contrary to experience, which reveals one perception of each object); or (3) there is one point that perceives the whole and every part (but that point is either a mathematical point, which according to Cudworth is an abstraction and thus cannot be a real part, or a corporeal, indivisible least part, which is impossible given the infinite divisibility of body, and which would anyway be incapable of distinct perception of all the parts). (824–25) Cudworth elaborates the argument by ruling out a fourth possibility, viz. that only the whole perceives the whole and all its parts, with no part of the soul having any perception at all. The perception of such a soul would of course be an emergent property, and moreover, if only the whole soul can perceive, then it is to that extent indivisible. Plotinus is the source for still another argument, in which he conveys the image of perceptions in the mind as radii converging on the center of a circle. The argument is based on sympathy or ‘homopathy,’ according to which, it is one thing that perceives pain in different parts of the body and takes steps to relieve it. The conclusion is, that in Men and Animals, there is One thing Indivisibly the Same, that Comprehendeth the Whole Outside of them, Perceiveth both the Parts, and the Whole of Sensible Objects, and all transmitted through several Senses; Sympathizeth with all the Distant Parts of the Body; and Acteth entirely upon all. And this is properly called, I My Self, not the Extended Bulk of the Body, which is not One but Many Substances, but an Unextended and Indivisible Unity, wherein all Lines meet, and Concentre, not as a Mathematical Point, or least Extensum; But as one Self-Active, Living Power, Substantial, or Inside-Being, that containeth, Holdeth, and Connecteth all together. (826)

Cudworth is unclear on how much is to be invested in the self as opposed to a merely incorporeal substance, but it is an important question raised by the work of other authors below. Still another, distant version of the Achilles is drawn from both Plotinus and Aristotle, and, although it is in the end a petitio, it perhaps reveals more than do the others the intuition that drives Cudworth’s deployment of all of them. The thrust of the argument is that unextended things, such as abstract essences, which are indivisible, can be perceived and understood only by an indivisible mind. ‘Nay, the Soul conceives Extended things themselves, Unextendedly and Indivisibly; for as the Distance of a whole Hemisphere is contracted into a narrow Compass in the Pupil of the Eye, so are all Distances yet more contracted in the Soul it self, and there Understood Indistantly; For the Thought of a Mile Distance, or of Ten thousand Miles, or Semidiameters of the Earth, takes up no more Room in the Soul, nor Stretches it any more, than does the Thought of a Foot or Inch, or indeed of a Mathematical Point’ (827). What is thought about is extended, but thought of it is not. Strictly speaking, this argument is not an Achilles even in the narrow sense identified in the Introduction to this volume, for it does not involve integration of parts. But it mimics the Achilles by drawing attention to how perception ‘contracts to a narrow compass.’ More importantly, it captures the broad intuition behind the Achilles that mental phenomena require an ontology beyond anything materialism can muster. What is material and perceived at a distance is perceived ‘immaterially and indistantly’ in the soul. Elsewhere in this volume, Lorne Falkenstein takes

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this text to be at least a gesture in the direction of an ‘intentionalist’ reading of the Achilles. As will be seen below, it would thus be important to any connection between Cudworth and Bayle. His argument concludes with a version of the Achilles that recalls the Proclean Achilles, styled, however, from cloth found in Descartes and Plotinus. This version addresses the question of how the relation between thought and extension is to be conceived. First, they can be conceived (as existing) apart from each other. From this it follows that they can exist apart from each other. Extension here for Cudworth is the Cartesian res extensa, a substance (829). The thoughts under discussion are modes. But ‘no Mode of any thing can be Conceived without that whereof it is a Mode’ (830). Their conceivability apart shows thought not to be a mode of extension, and thus not to be extended. Although he is at best only alluded to, Spinoza’s monism is also attacked by the conceivability apart of thought and extension. On his view, thought and extension as attributes are different ways of conceiving ‘one and the self same substance’ (830). But a thought, according to Cudworth, is such that what has it must be a single substance that excludes extension. Minds ‘are such Tight and Compact things, and have such Self-Unity in their Nature, as that they cannot be lodged [in what is extended]. Nor is it conceivable, how all the several Parts of an Extended Magnitude, should joyntly concur and contribute, to the Production of One and the same Single and Indivisible Cogitation; or how that whole heap or Bundle of things, should be One Thinker. A Thinker, is a Monade, or one Single Substance, and not a Heap of Substances: whereas no Body or Extended thing, is One, but Many Substances, every Conceivable or Smallest part thereof, being a Real Substance but it self’ (830). Second, thought and extension cannot be conceived (as existing) together. If they were to exist with each other, thoughts would be extended, and it would make sense, as it in fact does not, to think of them as (literally) shaped, measurable, and divisible. In addition, if thoughts are extended then so must the soul having them.10 But if extended thoughts are inconceivable, so must be an extended soul. Here Cudworth quotes Plotinus and reads him in a way that anticipates Kant’s image of the words that fail to compose a verse: ‘In all Magnitude or Extension, This is One thing, That is Another.’ Extended things are like the words of a verse that can be re-arranged, each now in a given place but then in another. According to Cudworth, in such a case, God, at least, could divide a thought and the mind with it into multiple parts and ‘remove them to the Greatest Distances from one another, . . .in which case, neither of them alone, would be Soul or Mind, Life or Thought, but all put together, make up one entire Mind, Soul, Life, and Thought’ (829).

10

This argument was used by Simon Foucher, Locke, and Condillac. Richard A. Watson, The Downfall of Cartesianism, (The Hague: Martinus Nijhoff, 1966) Ch. 3; Thomas M. Lennon, ‘Philosophical Commentary,’ in Nicolas Malebranche, The Search After Truth, trans. Thomas M. Lennon & Paul J. Olscamp (Columbus: Ohio State University Press, 1980) 793; Lorne Falkenstein, ‘Condillac’s Paradox,’ Journal of the History of Philosophy, 43 (2005), 403ff.

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8.2 Bayle The Achilles occurs most notably in remark E of Bayle’s entry on Leucippus in his Dictionary. The context is the difficulty posed by Galen and Plutarch for materialist atomism that no combination of atoms could be animate and conscious if its constituent atoms were inanimate and unconscious. Bayle wonders why no atomist took the bit and asserted (in rather proleptically Leibnizian fashion, it would seem) that all atoms are themselves animate. He acknowledges that, according to Plutarch, Democritus might have held such a view, but neither Leucippus, nor Epicurus, nor any of their followers held the view—presumably because they were concerned to show that the soul is mortal, and to endow atoms with thought would upset any proof of the soul’s mortality based upon its dissolution into unconscious constituents.11 Moreover, such a view would have had another great advantage, he says. It would have provided them ‘with some answers to an unsurmountable objection, to which their opinion is exposed, who maintain that matter may think, that is, be capable of sensation and knowledge. This objection is founded on the unity, properly so called, which must belong to thinking beings; for if a thinking substance were no otherwise one, than as a globe is one, it would never see a whole tree; it would never feel pain upon the blow of a stick’ (III, 790a). As we shall now see, the globe argument is (a version of) the Plotinian Achilles, and the pain argument (a version of) the Proclean Achilles. The text appears to express an Achilles, but the direction in which it leads is very different from the traditional one found in Cudworth. Even so, it preserves the intuition driving Cudworth’s various versions of the Achilles that materialism is inadequate to explain the unity of our thought. Moreover, Bayle’s two arguments are extensions of the Plotinian and Proclean arguments. Here is the first one. Notice, Bayle’s argument at his point is not the traditional Achilles that the multiplicity of what the mind perceives requires unification in a unified consciousness which itself can exist only in a simple and thus immaterial (and immortal) substance. Instead, he treats the soul, its consciousness and the idea or representation as a single entity, that is, one without parts (a rather Cartesian view, aside from the materialism it is invoked to express) and argues that only it and not the complex soul supposed by the materialists can represent (in the sense of perceiving, i.e. presenting to itself) a complex object as unified. He illustrates his contention by supposing the allegedly complex soul to be like an object that we ordinarily take to represent something else, viz. a terrestrial globe. Let us consider the figure of the four parts of the world upon a globe; you will see nothing on this globe which contains all of Asia, or even a whole river. The part, which represent Persia, is not the same with that which represents the kingdom of Siam; and you distinguish a right side and a left side in that part, which represents the Euphrates. From hence it follows, that if this globe was capable of knowing the figures it is adorned with, it would contain nothing which could say, I know all Europe, all France, all the town of Amsterdam, all the

11 On this point, Bayle refers to art. Lucretius, rem. Q, where in fact this connection is made explicit. See also, art. Epicurus, rem. F; art. Democritus, rem. P.

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Vistula; each part of the globe could only know that portion of the figure, which fell to it’s lot; and as this portion would be too small to represent any one place entire, the globe’s capacity of knowing would be entirely useless; no one act of knowledge could result from that capacity; at least it’s acts of knowledge would be very different from those which we experience; for these represent to us all the whole object, a whole tree, a whole horse, etc. An evident proof, that the subject, affected with the whole range of these objects, is not divisible into many parts, and consequently that man, as a thinking being, is not corporeal, or material, or divided, or compounded of many beings.12

So, the fact is that the mind perceives the whole of a complex object such a tree or a geographical region; but if the mind had parts, each part would represent but one part of the complex object. The reason for this, unexpressed by Bayle, seems to be that there would be nothing to perceive the whole as a whole. Needed would be something to perceive the relations between all the parts of the so-called mind and the parts of the object of which it is aware. That perception must itself must be simple lest the very same problem be replicated. But how does even a simple perception solve the problem? Another difficulty is that even an indivisible atom has parts, so that biting the bullet to make all atoms animate and conscious does not help, despite Bayle’s claim that it does. But there is a still deeper issue. As a first approximation, mapping might be taken to be a relation: a maps b. But no one thing intrinsically maps any other thing, however much it might resemble or other wise be related to that other thing. Or, to put it another way, every thing maps, or can map, every other thing. For mapping is better construed as a threeterm relation: a maps b for c. A part of the globe maps a part of the earth only for someone. Moreover, not everything is a substitution instance for c. For the point is that the third item views both of the others as wholes and sees one to be a map of the other. Even providing an interpretation of the map, a legend, only adds another relatum without solving the problem of how the map comes to be a map. For the legend is no more a natural relation than mapping itself; it is a convention that needs interpretation by someone in order to be what it is. But this relation, however many terms it might have, cannot be the whole of the story. Seeing in this sense must be a higher order relation: that in virtue of which the first relation obtains. This status of seeing is suggested by Kant’s example, which ties this apparent digression directly to the Achilles. His version of it involves the familiar claim from both Cudworth and Bayle, among many others, that if a thought had parts, only all the parts together would be the whole thought, and the conclusion that no such thought is possible. ‘For representations (for instance, the single words of a verse), distributed among different beings, never make up a whole thought (or verse), and it is therefore impossible that a thought should inhere in what is

12

Jean-Pierre Schachter makes the historically and philosophically ingenious suggestion that what Bayle has in mind with his example of the globe is Descartes’s theory of visual perception. The globe is the human eye with its retinal image; or, more precisely, the pineal gland whose parts, or states, no less than the parts of the retina correspond to parts of what is represented. ‘Pierre Bayle . . .,’ 258–59.

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essentially composite.’13 But the single words of a verse do compose that verse. The first verse of the Aeneid is composed of the word arma and the rest of the words of that famous verse, and not by any other words such as oris, which help to compose the second verse. So what is Kant’s point? To get at his point, an indirect route might be taken via another question: how does the relation between the verse and its parts differ from the relation between an apple and its parts? Or, for that matter, between the color and shape of the apple? The answer of the atomist Hume is that they do not differ, that in all three cases the unity can be provided only by a viewer. Or, to be more precise, because he rejects the Achilles, the illusion of unity is provided only by the fiction or illusion of a viewer. The upshot of Hume’s treatment of this ‘remarkable’ argument is that on the basis of the Cartesian criterion for a real distinction, which he accepts, every simple perception is a substance because it can be conceived apart from every other and, indeed, from everything else.14 The apparent unity of both object and viewer comes from the same source, the laws of empirical psychology. These laws connect objects, viewers and viewers to objects in the same terms. The upshot of this atomist line is that there is no intrinsic difference between viewers and objects. Both are composed of perceptions, which are not of anything. The only question of relevance here that Hume poses about perceptions concerns their causal origin; but the cause of an impression is not its object, and in any case is not known.15 Even ideas, though said to be copies of impressions, seem rather to be faint instances of impressions, or, as they are for Hobbes, decaying states of them. When Bayle collapsed the soul-consciousness-idea distinctions, he in effect avoided before the fact Kant’s objection to the Achilles as yielding something on which immortality might based. Instead, what begins to emerge in Bayle on the basis of the Achilles is a sui generis relation of intentionality that atomism, Humean or otherwise, does not countenance. The viewer stands outside the map and what it maps, and sees the one to be a map of the other. In fact, the point of the Achilles is that the application of such spatial language to the mind is inappropriate. It can only be figuratively that we speak of what is ‘outside’ the mind, what is ‘apart from’ it, what is ‘at a distance from’ it, etc. The failure to see the figurative nature of spatial language applied to mind bedeviled early modern philosophy. (Consider just Berkeley’s New Theory of Vision, which he tells us was written to defend his thesis that everything perceived exists only ‘in’ the mind against the objection that things are perceived ‘at a distance’ from it. Or Malebranches’s ‘strolling mind’ at the outset of the second part of book three in the Search After Truth. Or. . . .) Thus, for once at least, it might be appropriate for Cudworth to use the colorfully neologistic language he does (of which a healthy dose was for this reason deliberately administered above). When he speaks of the mind as an ‘Inside-Being,’ and says

13

The Critique of Pure Reason, trans. Kemp Smith, 335. Treatise, 1.4.5. 15 Treatise, 1.1.2. 14

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that extended things at a distance are understood there ‘Indistantly,’ he might be struggling with what cannot be extensionally expressed, only figuratively suggested. But something beyond its non-spatiality must be said about intentionality to connect it to the Achilles. A bit of speculation might help. How many things are involved in an apple’s being red and round? Nominalists might say just one: the apple. Others might say three: the apple, its color and its shape. Others, even more generous, might count other things such as ties between the apple and its shape and color. Whatever the total, call it N. How many things are involved when I see that the apple is red and round? Simplifying, let us collapse, with Bayle, any distinction some might draw between me, my thought, and a representation of the apple. Some might immediately answer, N+1. The answer given by those who recognize the sort of intentionality intended here is 2, regardless of what N might be. How so? For them, I see only one thing, namely, a red-round-apple, or if you will, the fact that the apple is red and round (and mutatis mutandis for everything else of which I am ever aware). Kant rejects transcendental realism and with it all intentionality of this sort. Instead, he agrees with Hume that the data of experience are atomistic and then has to look for a synthesizer, which is the mind itself (also in agreement with Hume, although the synthesis occurs according to something much stronger than the laws of empirical psychology). In broadest terms, by contrast, the Achilles is an argument to the effect that only a mind of a sort that is radically different from matter can perceive what is already unified. The tradition underlines that difference by describing the mind as immaterial. But the immateriality of mind is unimportant—consider the contemporary materialist John Searle, who argues for the sort of irreducible intentionality under discussion here.16 What is important, even for Bayle, is the impoverished atomist ontology that at best yields only a correspondence between points of the object and conscious points in the putative mind. Such points in the mind are, in the atomists’ own terms, too small to know anything but a point in the object. ‘No one act of knowledge could result from that capacity; at least it’s acts of knowledge would be very different from those which we experience; for these represent to us all the whole object, a whole tree, a whole, horse, &c. An evident proof, that the subject, affected with the whole image of these objects, is not divisible into many parts, and consequently that man, as a thinking being, is not corporeal, or material, or divided, or compounded of many beings.’ Non-intentional awarenesses of the atomist sort are possible, but do not yield knowledge as we understand and experience it. According to Bayle, thinking matter would violate the unity of consciousness in two radically different ways, whose difference tends to be obscured by his initial presentation of them together as he begins his argument against such a possibility. He argues that if the putatively thinking thing ‘were unified only in the way that a sphere is,’ that is, if it were only an aggregate or heap of infinitely (or, at least,

16

‘Intentional states are both caused by and realized in the structure of the brain.’ Intentionality, (Cambridge: Cambridge University Press, 1983) p. 15.

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indefinitely) many spatially juxtaposed parts, ‘it would never see a whole tree; it would never feel pain upon the blow of a stick.’ Now, seeing trees and feeling pains, despite the similar surface grammar of reports of them, might be very different kinds of mental phenomena. Prima facie, we distinguish between a tree and the seeing of it; in this respect, seeing a tree is like kicking a stone. At a deeper grammatical level, the stone is expressed by an ineliminable substantive accusative that is external to the verb. But pain is not something different from the feeling of it; it this respect, feeling a pain is like dancing a waltz. The pain is expressed by an accusative internal to the verb, and might be eliminated in favor of an adverb (feeling painfully, dancing waltzingly). In short, seeing a tree is intentional; feeling a pain is not. (In this sense, only the first of Bayle’s examples qualifies as an Achilles in the strict sense. For only it involves an object with respect to which the question of unity is able to arise.) If the globe argument is sufficient to refute materialism, why does Bayle move on to the pain argument? And why does he run them together? Now, the intentionality of thought is the topic of the long debate between Malebranche and Arnauld over the nature of ideas, a debate in which Bayle took an interest right from its outset. In fact, the whole debate might without much loss be reduced to the single question as to whether all thought is, contrary to the prima facie distinction above, by it very nature intentional. Such was the view of Arnauld. ‘As it is clear that I think, so it is also clear that I think of something, that is, that I know [connois] and am aware of something [apperçois]. For thought is essentially that. And so, given that there can be no thought or knowledge [connoisance] without an object known, I can no more trouble myself for the reason why I think about something than why I think, since it is impossible to think without thinking of something.’ Arnauld’s theory of ideas proper begins when he continues: ‘but I can well wonder, why do I think of one thing rather than another?’17 The short version of his theory is that an idea can be understood in two senses: as a mode of the mind, and in this sense it is called a perception, and as the thing perceived in so far as it is in the mind. Ideas as modes are essentially representative in so far as they present to the mind objects other than itself as things perceived by it.18 Malebranche makes a rather dramatic claim that seems to endorse Arnauld’s view. ‘To see nothing is not to see; to think of nothing is not to think. . . . Properly thinking, this is the first principle of all knowledge.’19 But for him, it is only a contingent fact that all human thought is intentional. The intentionality of mind depends on a relation that goes beyond the mind’s nature as a thinking thing. By themselves, the mind’s modes are epistemically opaque: they do not and cannot represent to the mind anything outside itself. The mind’s modes gain access to a material thing only when connected to the exemplar in God’s mind on the model of which it was created. The primacy of intentionality for Malebranche is not

17

Oeuvres de Messire Antoine Arnauld, (Paris, 1775–83) vol. 38, 134. The distinction is the familiar one between formal and objective reality in Meditations III. 19 Malebranche, 320. 18

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ontological, but epistemological: if thought were not intentional, i.e. if the mind did not have access to Ideas, there would be no knowledge. But intentionality itself, although it might be sui generis, is superadded.20 Details aside, Malebranche takes a view exactly opposite to that of Arnauld (and no less contrary to the prima facie distinction drawn above); he claims that no thought is by its very nature intentional. Malebranche has a number of arguments against the intrinsic intentionality of mental modes. One that would have appealed to Bayle is based on a shared conception of modes. The mode of a thing is nothing more than that thing existing in a certain way. (The roundness of a thing, for example, is but that thing shaped in a certain way, with the parts of its surface equally distant from a central point.) But this means that the mode of a soul can represent only that soul, i.e. in so far as it represents its perception of an object, but not that object itself.21 From the outset, even if he found Malebranche’s theory of ideas difficult to accept, Bayle was generally sympathetic to the position he argued against Arnauld. In particular, he defended Malebranche’s side in this debate specifically with respect to the intentionality of pleasure. For Malebranche, pleasure does not look beyond itself, and in itself it makes those who enjoy it happy while they enjoy it. Consonant with his general view of the intentionality of all mental phenomena, Arnauld argued that there is an intrinsic distinction between pleasures on the basis of the object of the pleasures. Not incidentally, he thinks that Malebranche’s view justifies concupiscence and thus upsets one of the main proofs of original sin. According to Bayle, the various kinds of pleasure, and their moral status, are distinguished on the basis of their efficient cause, not their formal cause. While there may be no difference in the pleasure itself caused by the sovereign good and some base passion, they nonetheless differ just in virtue of the difference in their causes.22 Given his rejection of Arnauld’s view that all thought is intentional, it should not be surprising that by far the greatest part of Bayle’s attention should be directed not to the globe argument, but to the pain argument. To be sure, the globe argument qualifies as a proper Achilles, expressing what Bayle calls the ‘unsurmountable objection’ that is based on ‘the unity that ought to belong to thinking beings.’ But that argument carries only on the assumption that at least some thought is intrinsically intentional. In rejecting that assumption, Bayle needs another argument, which is the pain argument. It too is based on the ‘unity . . .which must belong to thinking things,’ which is why he runs the two arguments together. But the pain argument leads to a very different sort of intentionality.

20 ‘Superaddition’ is Locke’s technical term for the action of God in making matter capable of attraction, and, for all we know, of thought. An important part of the background to Bayle’s interest in the Achilles is Locke’s debate with Stillingfleet on this issue, which he followed in the Nouvelles de la République des Lettres. See art. Dicaearchus, rem. M. 21 Least of all would it, as a finite, particular thing, be able to represent and infinite, general thing. Malebranche, 806. 22 For the context and fuller story, see Thomas M. Lennon, Reading Bayle, (Toronto: University of Toronto Press, 1999) 54–58.

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The pain argument proceeds almost entirely by way of rebuttal of a reply to an objection to a material mind. The objection follows immediately upon the conclusion of the globe argument, and does so in way that, like the initial statement of the globe and pain arguments, suggests that they are of a piece. The conclusion of the globe argument, he says, is ‘an evident proof, that the subject, affected with the whole image of these objects [a whole tree, a whole horse, etc], is not divisible into many parts, and consequently that man, as a thinking being, is not corporeal, or material, or divided, or compounded of many beings. If he were, he would be perfectly insensible of the stroke of a stick, since the pain would divide itself into as many particles as the member smitten consists of. But these members consist of infinite particles; so that the portion of pain, which belonged to each part would be too small to be perceived or felt.’ The rebuttal consists of a string of arguments, at the end of which Bayle summarily returns to a version of the Achilles. ‘But I let that pass, and only ask you, whether your supposition does not manifestly include this monstrous absurdity; that in a famished dog, there are infinite substances, which feel the gnawings of hunger, and, in a man who reads there are infinite things, which read and know each what they read. Nevertheless, we all know by experience, that there is only one thing in us, which knows that it reads, that it is hungry, that it feels pain or joy, & c.’ This is a rather different consideration from Cudworth’s homopathy argument, which concludes that soul must be simple on the basis of its ability to judge disparate elements. (This is an argument that Bayle took note of in his review of a work by the abbé Dangeau, taking it in fact to be as certain as a geometrical demonstration.23) But here we get a version of the Achilles based on introspection which yields knowledge of a unified self. According to Malebranche, even though the mind’s modes are by themselves epistemically opaque, with no reference by themselves, they nonetheless provide knowledge of the mind or soul at least to that extent, viz. that it is capable of that sort of mode. But this sort of experiential knowledge, or inner sensation as Malebranche calls it, does not yield an idea of the mind, and in that sense it is incomplete. (In this, as he realizes, he departs from the Cartesian view that we have an idea of the mind making it better known than the body.24) Nor is it accidental that he uses the same expression that Cudworth was later to use for the mind’s introspective knowledge of itself. Both are Platonists for whom this inner sensation, like all sensation, yields acquaintance only of a particular. Even so, according to Malebranche, this knowledge is sufficient to demonstrate, by drawing a contrast between it and what is known about body (a priori, on the basis of the idea we have of it), the immortality and spirituality of the soul.25 Indeed, if I had only the idea of the soul, my knowledge of it would not be complete. For the idea would not yield knowledge of my soul, except generically.

23

See Schachter, 247–49. Elucidation XI, in Malebranche, 633. 25 Malebranche, 239. 24

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I would know the kind of thing the soul is, and thus all the sorts of modes of which it is capable, in the way that the idea of body as extension yields all the geometrical properties of which it is capable. But the individuality of my mind would elude me unless I also had the a posteriori awareness that comes only from the contingent occurrence of its modes. In fact, the same is true of the awareness of individual bodies. For all the Cartesians, certainly for both Malebranche and Arnauld, the idea of body gives me only body; to be aware of an individual body, I need color or some other mental mode to individuate it. All of this is detailed in the long exchange of views between Malebranche and Arnauld that Bayle followed. There is a deeper issue, however, that ties the pain argument to the globe argument as an instance of the Achilles. For there is an additional sense in which inner sensation might be taken to be intentional. Arnauld begins his theory of ideas with two ‘remarks,’ as he calls them. ‘The first is that our thought or perception is reflective on itself; or, as Latin better puts it, it is conscious of itself [est sui conscius]. For I do not think without knowing that I think.’26 Now, thought, of course, is the essence of the mind, and thus reflection yields for Arnauld the good Cartesian the complete knowledge of the mind rejected by Malebranche. But whether or not I know what I am, I might yet know myself as myself. Reflective inner sensation might reveal a self. Contrary to the explicit report of Hume, who almost certainly had these views in mind, when I look into my self I might find my self.27 Now, it is not altogether clear that this is the view that Arnauld is espousing. After all, his contention is that thought is reflective in that I cannot think without both knowing that I am thinking and knowing what it is that I am thinking about.28 Reflection might yield only mental acts, not the simple substance that is supposed to have them. Moreover, for Descartes, at least, reflection is the kind of awareness whereby innate ideas are disclosed, which is to say that it yields knowledge of kinds rather than of a self. Nonetheless, this proleptically anti-Humean view is to be found in the very Cartesian source that Bayle cites at the end of the pain argument: ‘no one, in my opinion, has treated this important question about the immortality and individuality of whatever thinks, more sublimely and solidly than Dom Francis Lamy of the congregation of St. Maur, in his work of the knowledge of one’s self [sic].’ (Note how the translator Desmaizeaux reads the title of Lamy’s work, which in the original deploys only the reflexive ‘oneself.’) The work to which Bayle refers is De la connoissance de soi-même, which appeared in six volumes, 1694–96, by a Benedictine follower of Malebranche, whom Bayle was later to call ‘one of the most cogent of the French Cartesians.’29 Bouillier says of this, his ‘most considerable work,’ that it is ‘an imitation of [Malebranche’s

26

Arnauld, 204. Arnauld cites Augustine, De Trinitate, book ten, chapter ten, and Descartes, especially the definitions at the outset of the geometrical proofs. This is a view typical of the Cartesians. 27 Treatise of Human Nature, 1.6.6. 28 Ibid. 29 Réponse aux questions d’un provincial, cxli; in Oeuvres Diverses de . . . Bayle (1737) Hildesheim: Georg Olms, 1966) III, 788.

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Search After Truth] . . . On every page one finds imitations and echoes of the Search. Lamy follows Malebranche where he follows Descartes and departs from Descartes where Malebranche does.’ The thrust of the work is to indicate the importance of knowledge of the self, to explain its failure to be better known despite its presence to itself, and to show how it can be better known. One of the points on which Lamy follows Malebranche in departing from Descartes is in rejecting the primacy of the cogito, and the reliance on inner sensation as the way to gain knowledge of the self.30 The text that Bayle almost certainly has in mind, however, might go beyond anything articulated by Malebranche to anticipate, in a perhaps unprecedented way, Kant’s transcendental unity of apperception. In the ‘eight reflections on the properties of the soul,’ Lamy deploys various arguments to show that the essence of the soul must be thought since only it can account for the properties that he has already shown to attach to the soul.31 The key premises are from familiar arguments found in Descartes, but also Cudworth, such as the conceivability apart of thought and extension. In addition to immateriality, the properties include unity, freedom, spirituality, and ultimately immortality, but also indivisibility, which is discussed as follows: ‘the indivisibility of the soul is a necessary consequence of its nature. The conscious me [le moi apercevant], or, to put it this way, the I think [le j’aperçois] does not allow division; and I challenge anyone to give me, or to conceive, a half, or a third, or a quarter of a perception.’32 Now, the ‘I think’ certainly refers to a simple substance for Lamy; after all, immortality is based on it. (Thus he draws the ontological conclusion condemned by Kant in the Second Paralogism.) But prima facie it need only be an indivisible mental act discoverable by inner sensation. A reading of his ‘I think’ in these terms might be given to what Lamy has to say about unity. ‘Not only do I perceive [sens bien] that there is in me a conscious being [un être apercevant], an I think [un j’aperçois], but I even conceive that there cannot be a second one, entirely different from myself—in short, the idea of my conscious me [mon moi apercevant] excludes every other conscious self, and it would be a contradiction for there to be more than one.’ The great attraction of this Kantian line beyond Malebranche’s position, for example, is that it obviously avoids the world soul of Latin Averroism, according to which there is no personal immortality. The soul that is immortal is not my own, personal soul, but the soul that I have I common with everyone else. Such was the view that the Cartesian Pierre-Sylvain Regis fell into in 1689. However, to suggest the further Kantian reading that the ‘I think’ carries no ontological weight, not even that of a stand-alone act, is to go far beyond the warrant of the text, especially the text of one who despite Bayle’s words of praise, is philosophically not very sophisticated.

30

Francisque Bouillier, Histoire de la philosophie cartésienne (Paris, 3rd ed. 1868) vol. 2, 367–69. De la connoissance de soi-meme, vol. 2, 381ff. Thus he gives an Achilles according to what Descartes would call the analytic method, when, for example, he argues that the soul’s essence must be thought since its immateriality depends on thought. 32 Ibid. 31

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8.3 Connections So much for the pain argument; what of the globe argument, on what resources might Bayle be drawing for it? Cudworth only alluded to Simplicius’s Proclean argument from reflection; hence, apart from his argument based on homopathy, he would have been of little help with the pain argument. But he developed arguments that could have inspired the globe argument. As it happens, Bayle knew of Cudworth, about whom he made a remark more aptly applicable to himself: ‘one of the most capable men of the seventeenth century, [who] combined two qualities rarely found together: prodigious reading and extraordinary insight.’33 Moreover, although Bayle had serious problems with Cudworth’s signature doctrine of plastic natures,34 he was impressed with Cudworth’s argument against materialism based on the inability of matter to think. A problem with tracing an influence to Cudworth is that Bayle had no English: ‘I do not know Cudworth’s work from having read it (my lack of English made that impossible) but only from its general acclaim [par la voix de la renommée] and from the extracts published by Leclerc.’ Had Bayle been able to read English, then it would have been straightforward to look for a connection between Cudworth and not only the elaborated Achilles of the Dictionary, but also a much earlier, compressed version.35 This version appeared around 1680, and thus lies outside the speculated connections below. But since it is an Achilles, the speculation, even if it should turn out to be true, would not explain Bayle’s discovery of the Achilles, but only his later focus on it and, perhaps, his development of it. In addition, Bayle undeniably had access to a fully elaborated Broad Achilles, prior to the publication of Cudworth’s work. This is the version of it to be found in the Quatre Dialogues by the two abbés De Choisy and Dangeau. Bayle reviewed their work for the Nouvelles de la République des Lettres in August of 1684. Based on Aristotelian considerations of cross-sensory judgments, the argument as Bayle states it concludes that the soul must be simple, thus indivisible, and thus immortal. His comment is that ‘it might be said without exaggeration that ‘it is a demonstration as certain as those of geometry.’36 33

Oeuvres III, 881. John Passmore, Ralph Cudworth: An interpretation (Cambridge: Cambridge University Press, 1951) 27. These problems led to an acrimonious debate with Jean Leclerc, who defended Cudworth. Susan Rosa, ‘Ralph Cudworth in the République des Lettres: The Controversy about Plastic Natures and the Reputation of Pierre Bayle,’ Studies in Eighteenth-Century Culture 23 (1994) 147–60. 35 ‘If this [mental] substance were extended, . . .it would be incapable of thinking, because a thinking thing must be one, and no thinking thing is one . . ..Indeed, it would be composed of several substances, as our body is composed of several members, it could never see an entire object, and one of its parts would see one part of the object, while another of its parts would see another part of this same object such that there would be nothing in the thinking thing that could truly say “I see this whole stone”.’ Theses philosophicae, xi, in Oeuvres IV, 142–43. Todd Ryan draws attention to this text in his ‘Bayle’s Defense of Mind-Body Dualism.’ Aufklärung 16 (2004) 191–211. 36 Oeuvres I, 110. Schachter thoroughly discusses this version of the argument. Loc. cit. Although the statement of the argument is not without sophistication, the work of the two abbés is a fairly popularized dialogue in which discussion of sources would be out of place. 34

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In any case, the text in which Bayle deploys the Achilles was an inclusion in the second edition only of the Dictionary; so one looks for a text between it, published in December of 1701 and the first edition, published in October of 1696. The Achilles, in all of Cudworth’s versions, is to be found in the paraphrases of Cudworth included in the Bibliothèque choisie by Leclerc. Alas, the paraphrases did not begin to appear until 1703, and the Achilles not until 1706.37 So the case comes down either to the intellectual scuttlebutt reported in the letter cited above, or to pre-publication access to Leclerc’s material, which is not impossible, for two reasons. First, Bayle and Leclerc were longtime correspondents, and secondly, Bayle’s laudatory reference to Cudworth’s proof of the immateriality of the soul, and the long argument he based on it, occurs in the third part of his Réponse aux questions d’un provincial, which appeared in November of 1706.38 Perhaps he had just enough time to compose this material from what he read in the Bibliothèque choisie; but perhaps he already had access to it. If there is not a direct causal connection between Cudworth and the Dictionary, there might be at least an indirect generic relation. In 1687, Simon Foucher published an Apologie, in which he attempted to show that the philosophy of the Academics was both consonant with common sense and useful to the cause of religion. In particular, he tried to demonstrate the immortality of the soul from its simplicity based on the unity of consciousness.39 We do not get a globe argument as such, but he does relate an argument in which Plotinus draws on the account in the Timaeus of the construction of the soul, and thereby of individual souls, from existence, sameness, and difference.40 As do both Plato and Plotinus, Foucher appeals to a dual nature of the soul as indivisible and yet divided among bodies. He adapts a term of art from Malebranche to explain this notion. Malebranche called the exemplar, or the Idea in God after which He creates the material world, intelligible extension (étendue intelligible). Although it is the ground for the real extension of the material world, it does not make God materially or really extended. Moreover, this intelligible extension gives our sensations their intentionality in virtue of which we know materially extended things. He thus opts for the undeveloped possibility that Cudworth leaves open to his readers, viz. the denial of the materialists’ premise that whatever is extended is body. This duality of what is only intelligibly extended but related to what is materially extended is what Foucher is appealing to in his account of the soul, ‘having in itself a unity and substantial indivisibility applicable to

37

Vol. 8, pp. 86–92. See Rosa, for some discussion. She dates the initial material 1704. Oeuvres III, 940. 39 Mijuskovic draws attention to the passage, but his note 38, p. 78, seems not to get it quite right. The Achilles of Rationalist Arguments, (The Hague: Martinus Nijhoff, 1974). Foucher himself acknowledges the difficulty of the argument and says that he gives only a ‘distant view’ of it as something that ‘need not be made clear to everyone’ (p. 128). 40 Enneads IV. MacKenna, 255. Timaeus 35A. Cornford calls this sentence ‘one of the most obscure in the dialogue.’ Plato’s Cosmology (Indianapolis: Bobbs-Merrill, no date) 59. It is after this passage that Foucher makes the comment about his ‘distant view.’ 38

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different parts, and containing intelligible extension [étandue intellectuelle] which renders it applicable to different spatial parts.’41 Foucher’s Achilles is thus aimed not at the extended mind, but directly at the material mind, which would be separable into parts and thus cease to be capable of thought in the way in which, according to Kant, a verse separated into its words would cease to be a verse. But how, exactly, is non-material extension supposed to satisfy the demands of the Achilles? A version of non-material extension that arises in this context, rejected as unintelligible by Bayle and Hume, is an extension that is wholly in the whole of what it occupies, and wholly in every part of what it occupies. Speculatively, the idea would be that such an extended mind could immaterially take in the whole of any object because the whole of it would be present to every part of the object. But however attractive this gambit might be, it misses the point of the Achilles, that the mental is non-spatial. The only way to motivate such an account would be as a metaphorical, non-literally ontological expression of what minds are like, in particular how they differ from material things. But that is all the Achilles comes to as deployed by Bayle. Bayle does not mention Foucher in connection with his globe argument, and elsewhere his references to Foucher are spare, infrequent, and philosophically uninteresting. Still, Foucher places the Achilles in the philosophical tradition of which Bayle is a part.42 For the Academics whose principles are supposed to yield the Achilles are the Academic skeptics, so-called because of their early proprietorship of Plato’s Academy. They no less than the Neo-platonists laid claim to Plato’s legacy, and so, whatever the causal connections, Cudworth and Bayle on the Achilles are not so odd a coupling, after all. But notice that, like the causal connection through Leclerc, the generic connection at most explains Bayle’s return to the Achilles, and perhaps his elaboration of it, but not his initial discovery of the argument; for the early texts cited above, once again, date from around 1680 and 1684. What brought Bayle to it in the first instance remains unknown, as does the source for the two abbés version that Bayle reviewed.

41

Apologie, 128. For the interpretation of Bayle as an Academic skeptic, see my ‘What Kind of a Skeptic Was Bayle?’ Midwest Studies In Philosophy XXVI (2002) pp. 258–79. 42

Chapter 9

The Achilles Argument and the Nature of Matter in the Clarke Collins Correspondence Marleen Rozemond

9.1 Introduction The question whether we can establish the immateriality and immortality of the human soul was very important in the early modern period. Descartes’s dualistic approach to the issue is particularly prominent and continues to receive much attention from historians of philosophy as well as from less historically inclined philosophers. But other early moderns also devoted much attention to these issues and their work in this area has not received nearly as much attention. The Achilles Argument enjoyed significant popularity during the early modern period in this debate. Prominent in the 18th century was a discussion of the argument by Samuel Clarke, best known for his correspondence with Leibniz, and Anthony Collins. Collins was a freethinker, materialist, and deist well-known at the time in England. The correspondence started off with a response by Clarke to a book by Henry Dodwell who argued that the soul is not naturally, but only supernaturally immortal: God makes it continue to exist after death. Clarke responded with an open letter in which he offered a version of the Achilles Argument. It set off a public correspondence with Collins, who took Dodwell’s side. The Clarke-Collins correspondence took place during 1706–1708. It went through six editions, and was discussed in at least Britain and Amsterdam throughout much of the 18th century.1 Leibniz received the correspondence, and commented that he thought Clarke made some good points, while disagreeing with others and thus the Leibniz-Clarke correspondence was ignited.2 The correspondence took place against the background of Locke’s claim that we cannot rule out the possibility that God superadds thinking to matter. Consequently, M. Rozemond Department of Philosophy, The University of Toronto, 215 Huron Street, Toronto, Ontario, Canada N5S 1A2 Phone: (519) 905-828-5349, Fax: (416) 978-8703 e-mail: [email protected] 1 Robin Attfield, ‘Clarke, Collins and Compounds,’ (Journal of the History of Philosophy, 15, 1977, pp. 45–54), p. 47. 2 Robinet, Correspondence Leibniz-Clarke; présentée d’après les manuscrits originaux des bibliothèques de Hanovre et de Londres, (Paris: Presses Universitaires de France, 1957), p. 432.

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although he did think that we can establish that God is an immaterial thinking substance, Locke argued that we cannot establish the immateriality of the human mind.3 As a result Locke ignited a heated debate about the possibility of thinking matter. The thinking matter debate occupied a number of thinkers on both sides of the English Channel over the course of the next century. It has received relatively little attention from historians of philosophy, in spite of its importance at the time, and in spite of the prominence of the mind-body problem in contemporary angloamerican philosophy.4 A reason may be that much of the discussion was carried out by philosophers who tend to receive less attention than the canonical figures in this period – such as Berkeley, Leibniz, Hume. Clarke’s first letter, which was addressed to Dodwell, is very clear about the fact that important religious issues are at stake. Clarke claimed that an appropriate view of the afterlife is that the human soul is naturally immortal, that is, its nature is such that it cannot go out of existence as a result of natural processes. In view of this Clarke argued that the soul is simple and cannot be material. Clarke specifically criticizes Dodwell for his stance on the fate of the damned. According to Dodwell, human souls are naturally mortal, but God makes them immortal, some for happiness, others for punishment. But Clarke charges that no view can be more ‘harsh and incredible, than to suppose [God] by his Omnipotent Will and Power, eternally and miraculously preserving such Creatures unto endless Punishment, who never had in them, either originally or additionally, any Principle of Immortality at all.’ (W III 722).5 Clarke thinks it’s better to hold that ‘the Immortality of the Soul, and especially of a miserable one, [derives] from its own Nature than from the Divine Pleasure.’ The eternal punishment of the damned must be explained by the fact that ‘by willful continuance in Sin, having so far depraved themselves as to become uncapable of eternal Happiness, must consequently by the just Judgment of God fall into such Misery, as their immortal nature so corrupted necessarily makes them liable to’ (ibid.).6 Clarke returns to the religious stakes later in the correspondence and charges that materialism is a problem for religion because it threatens free will, opens the gates to believing that all rational beings are material, including God, and raises serious problems for the afterlife, threatening the resurrection and personal identity (W III 850). Clarke defended the natural immortality of the soul as follows. He argued that consciousness requires an ‘individual being’ for its subject. An individual being

3

For more on this see J.-P. Schachter’s paper on Locke in this volume. But see John W. Yolton, Thinking Matter: Materialism in Eighteenth-Century Britain (Minneapolis: University of Minnesota Press, 1983) and Locke and French Materialism (Oxford: Oxford University Press, 1991). 5 The correspondence can be found in Samuel Clarke, The Works, (W), (London, 1738, reprint, Garland Publishing, New York 1978) vol. III. I have preserved the capitalization, punctuation, spelling and italicization of the original. 6 At the same time, while for Clarke the soul is naturally immortal, he thinks its existence always depends on God, who can annihilate it at any time, a view commonly held in the period about all creatures (W III, 722). 4

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is an entity with a strong sort of unity; indeed, it must be a simple, indivisible entity. He argued that matter can never constitute such a being. Anthony Collins was unconvinced. Sometimes he simply contends that Clarke has failed to establish his claims, and he is certainly often right. His more specific and pointed objections to the argument fall into three categories: first, he raises the question what feature of consciousness requires such a subject; second, he wonders why matter can’t constitute a suitably unified individual, and third he argues that for all we know consciousness might belong to a system of matter in the following way: it might result from, or as we would now say, emerge from, material qualities that characterize the parts of the system of matter. I will examine their discussion of the first two objections. The last objection I will leave for another occasion; it occupies a large portion of the correspondence and constitutes a very interesting discussion of emergentism that is unusually detailed for the period.7 My aim in this paper is to understand where the fundamental disagreements lie that divide Clarke and Collins on the possibility of thinking matter. In the first section I will discuss Clarke’s initial statement of the argument and relate it to the classification of Achilles Arguments offered in the introduction to this volume. In the second section, I will turn to the discussion of what consciousness is, and why it requires a simple subject. On this point Clarke is rather disappointing: he is much more quiet than other proponents of the Achilles Argument about just what features of consciousness require a simple subject. The third section is devoted to the discussion of the nature of matter, which is crucial to Clarke’s claim that matter can’t constitute an individual being. This part of Clarke’s discussion displays clear affinity with Leibniz, his later antagonist, but Clarke’s position here is complicated by his view that the soul is extended. This examination of the Clarke-Collins correspondence provides then the following partial assessment to the question where their fundamental disagreements lie on the possibility of thinking matter (leaving aside their disagreement about emergentism). No clear disagreement emerges about the nature of thought or consciousness, that is, about the question what feature requires an individual subject. But there is a clear disagreement about the question whether matter can serve as its subject that springs from differences in their conceptions of matter. A philosopher’s conception of matter is an important topic for the Achilles Argument, but it is easily neglected as it is tempting to focus on the Achilles’ claims about the nature of consciousness. There is then a general lesson to be drawn from the correspondence to the effect that acceptance or rejection of the Achilles may hinge on a philosopher’s conception of matter.

7 Collins also raises objections that go beyond the argument and that concern problems for the view that a soul is simple: how should we understand changes in the states in a simple entity, or its being acted upon by the body or God? And, if we accept that animals are conscious beings, must we then accept that they too have simple, and hence immortal souls? In addition, the correspondence discusses free will, personal identity, and the nature of gravity. All these questions I will leave aside.

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9.2 The Achilles Argument In his first letter Clarke offers the following statement of the Achilles Argument: For Matter being a divisible Substance, consisting always of separable, nay of actually separate and distinct parts, ‘tis plain, that unless it were essentially Conscious, in which case every particle of Matter must consist of innumerable separate and distinct Consciousnesses, no system of it in any possible Composition or Division, can be any individual Conscious Being; For, suppose three or three hundred particles of Matter, at a Mile or any given distance one from another; is it possible that all those separate parts should in that State be one individual Conscious Being? Suppose then all these particles brought together into one System, so as to touch one another; will they thereby, or by any Motion or Composition whatsoever, become any whit less truly distinct Beings, than they were when at the greatest distance? How then can their being disposed in any possible System, make then one individual conscious Being? If you will suppose God by his infinite Power superadding Consciousness to the united Particles, yet still those Particles being really and necessarily as distinct Beings as ever, cannot be themselves the Subject in which that individual Consciousness inheres, but Consciousness can only be superadded by the addition of Something, which in all the Particles must still it self be but one individual Being. (W III 730)

This passage has clear affinity with the classical Achilles Argument, but it does not contain a straightforward statement of it. Most notably, it does not make any claims about the unification of representations. It offers an argument that in effect starts with the conclusion of what in this volume is called a Narrow Achilles. Recall a Narrow Achilles has the following structure: P1: Unification of representations takes place. P2: Only a simple, unified substance can unify representations. Therefore, C1: The human soul (or mind) is a simple unified substance.

Clarke here uses as a premise the claim that the subject of consciousness is a unified substance, and offers an argument for the immateriality of the soul, so in this initial statement he offers a version of the second half of a Broad Achilles which, recall, goes as follows: C1: The human soul is a simple unified substance. P3: If the human soul is a simple unified substance, then it is not material. P4: If the human soul is a simple unified substance then it is immortal. Therefore, C2: The human soul is immaterial and immortal.

The version Clarke offers here can be schematized as follows: (1) The subject of consciousness is an individual being. (2) Matter is infinitely divisible, any piece of matter consists of distinct parts, and cannot be one individual being. (3) Matter cannot be a subject of consciousness. And the subject of consciousness is the human soul. Clarke does not claim that the subject of consciousness must be simple, he says that it must be an individual being. The argument suggests that the subject must have a suitable type of unity, thus in principle leaving open the possibility of a composite subject. He then argues

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against the possibility of matter ever having that sort of unity. In fact it becomes clear that an individual subject must be simple for Clarke. As we saw, Clarke was much concerned with the (natural) immortality of the soul, but its immateriality is the focus of the discussion with Collins. Clarke’s argument raises immediately the following question: given that he does not offer an explicit Narrow Achilles, what ground does Clarke believe he has for asserting that consciousness requires an individual being for a subject? Does he rely on the unification of representations? This question is the subject of the next section, where we will see that Clarke does eventually offer something akin to the Narrow Achilles. At this point it is useful to note the relationship of Clarke and Collins’ positions to Locke’s – indeed, it is worth noting that both sometimes refer to Locke to support their arguments. Like Clarke, Locke thought that emergentism is not a possibility.8 In arguing for God being an immaterial, thinking substance he addresses the question whether thinking could emerge from material qualities and writes: . . .Matter, incogitative Matter and Motion, whatever changes it might produce of figure and bulk, could never produce Thought: Knowledge will still be as far beyond the Power of Motion and Matter to produce, as Matter is beyond the Power of nothing, or nonentity to produce. (Locke, Essay IV.X.10, p. 623)9

But Locke was famous in the period for arguing that we cannot rule out the possibility that God superadds thinking to matter: We have Ideas of Matter and Thinking, but possibly shall never be able to know, whether any mere material Being thinks, or no; it being impossible for us, by the contemplation of our own Ideas, without revelation, to discover whether Omnipotency has not given to some System of Matter fitly disposed, a power to perceive and think or else joined and fixed to Matter so disposed, a thinking immaterial Substance . . .(Essay IV.iii.6, pp. 540–1).

So Clarke and Locke agree in rejecting emergentism, and they both accepted a version of property dualism. But unlike Locke, Clarke thinks he can rule out the possibility of one substance being both material and thinking by divine superaddition. Like Leibniz, Clarke thought that God would have to add a substance that does the thinking.10 Collins, on the other hand, went farther than Locke and accepted both

8

But for an alternative interpretation see M.R. Ayers, ‘Mechanism, Superaddition, and the Proof of God’s Existence in Locke’s Essay.’ Philosophical Review 40, 1981, pp. 210–251. 9 An Essay Concerning Human Understanding, Peter H. Nidditch ed., Oxford: Clarendon Press, 1975. 10 On this issue Clarke is in agreement with Leibniz. See Leibniz’ letter to Damaris Masham of June 30, 1704, G III 355–356, translated in Leibniz’s ‘New System’ and Associated Contemporary Texts, R.S. Woolhouse and Richards Francks transl. (Oxford: Oxford University Press 1997), pp. 211–212. Unless indicated otherwise, the references to Leibniz’ writings in the original languages can be found in Die Philosophischen Schriften von Gottfried Wilhelm Leibniz, C.I. Gerhardt ed., 7 vols., Berlin, Wiedmann, 1875–90, repr. Hildesheim, Georg Olms, 1978 (G). Translations can generally be found in G.W. Leibniz, Philosophical Essays, Roger Ariew and Daniel Garber eds.,

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the possibility of one substance being material and thinking, and the possibility of thinking emerging from material qualities.

9.3 Consciousness What about consciousness requires an individual subject, according to Clarke? He introduces his reliance on the nature of consciousness quite deliberately: That the Soul cannot possibly be Material, is evident not only from the consideration of its noble Faculties, Capacities and Improvements, its large Comprehension and Memory; its Judgment, Power of Reasoning, and Moral Faculties; which Arguments have been urged with unanswerable Strength by the wisest and most considerate Men in all Ages from the times of Socrates and Plato to this very Day; but the same thing is moreover demonstrable from the single consideration, even of bare Sense or Consciousness it self. (W III 730)

Clarke is intent on distinguishing his argument from a tradition of arguing for the immateriality of the soul from the nature of the higher faculties of the human soul or mind. He explicitly separates his argument from ones proposed in the days of Socrates and Plato (without, however, noting what specific arguments he has in mind). This approach sets him apart also from an argument found in Aquinas and other scholastics who argued that the nature of the human intellect requires an immaterial subject (see, for instance, Summa theologiae 1.75.2). Similarly, in the Discourse on Method Descartes had argued that humans have a soul that is something beyond the body on the basis of higher human capacities: our linguistic capacity and the particularly wide range of human capacities that distinguish us from machines and beasts (AT VI 55–60/CSM I 139–141).11,12 Also worth considering is the comparison with Leibniz. Leibniz thought that monads are simple beings, characterized by perceptions and appetites. Perception he describes as ‘a state that contains and represents a multitude in a unity or in a simple substance’ (Monadology 14). Simply put, there is a sense in which Clarke

Indianapolis, Hackett, 1989 (AG), and in Philosophical Papers and Letters, Leroy E. Loemker ed., Dordrecht, Reidel, 1969 (L). 11 Reference to Descartes’s writings are as follows: AT: Charles Adam and Paul Tannery eds., ×uvres de Descartes, 11 vols. (Paris: CNRS and Vrin: 1964–176); CSM: The Philosophical Writings of Descartes, 3 vols. (Cambridge: Cambridge University Press, 1985–1991). 12 Descartes’s best-known argument for dualism, which can be found in the Meditations and Principles is often regarded as more broadly focused on consciousness where consciousness extends to sense and imagination – lower human capacities – as well as intellect. But some scholars, including myself, think the argument is based on features of the intellect, as was the case for Aquinas. Various texts suggest as much, and Descartes himself claimed that sensation actually indicates the union of the mind with the body rather than their distinctness. For discussion, see Margaret Wilson, Descartes (London: Routledge, 1978), pp. 177–185, and especially pp. 200–201, and my Descartes’s Dualism (Cambridge: Harvard University Press, 1998), Ch. 2.

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and Leibniz agree that the mental requires a simple subject, although for Leibniz not all mental states, perceptions, are characterized by consciousness.13 One consequence of Clarke’s approach is that it raises questions about the status of animal souls. In their defense of the immateriality of the soul in view of its immortality Aquinas and Descartes focused on capacities they presumed to be peculiar to humans. Consequently their arguments supported immortality for human souls, but not for the souls of non-rational animals.14 But Clarke’s focus on consciousness prompts Collins to query him about the souls of animals: are they too immaterial and naturally immortal? Clarke does not really resolve this issue.15 So one thing Clarke makes clear is that his argument is not limited to higher mental powers such as intellectual ones, or moral ones. But that still leaves us with the question what about consciousness requires a genuine individual for a subject and excludes the possibility of thinking matter. When Collins objects that Clarke has not explained what consciousness is, or why it does require such a subject, Clarke offers the following response: Consciousness, in the most strict and exact Sense of the Word, signifies neither a Capacity of Thinking, nor yet Actual Thinking, but the Reflex Act by which I know that I think, and that my Thoughts and Actions are my own and not Another’s. But in the present Question, the Reader needs not trouble himself with this Nicety of Distinction; but may understand it indifferently in all or any of these Significations; because the Argument proves universally, that Matter is neither capable of this Reflex Act, nor of the first Direct Act, nor of the Capacity of Thinking at all. (W III 784).

Clarke’s characterization of consciousness in the strict sense as ‘the Reflex Act by which I know that I think, and that my Thoughts and Actions are my own and not another’s’ is quite precise and offers a very specific view of what consciousness is. He is not talking about the kind of awareness that is at issue in recent arguments about the nature of what it’s like to be conscious, aware, experiencing various types of sensations, as in discussions generated by Nagel’s ‘What is it like to be a bat?’ Clarke is talking about self-consciousness in the sense of consciousness of one’s mental states as one’s own. So is something about self-consciousness what requires a simple subject for Clarke?

13 This agreement is not necessarily easy to state. For Leibniz the states of monads are all perceptions, but only a subset of those are thoughts and not nearly all are conscious. Thus interpreters have sometimes denied that Leibnizian perceptions in general are mental (McRae, Leibniz: Perception, Apperception and Thought Toronto: University of Toronto Press, 1976, p. 24), or have preferred to label them as semi-mental (Robert M. Adams, Leibniz: Determinist, Theist, Idealist, Oxford: Oxford University Press, 1994). I do think of perceptions as mental for Leibniz, but these complications raise the question in what sense this may be true. For discussion, see Alison Simmons ‘Changing the Cartesian Mind: Leibniz on Sensation, Representation and Consciousness,’ The Philosophical Review, 110, 2001, pp. 31–75. Simmons argues that while for Descartes the mental is characterized by consciousness, for Leibniz it is representationality. 14 Descartes insists on this point in the Discourse AT VI 55–60, CSM I 139–141. 15 For discussion of animals see W III 776–7, 795, 816.

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Elsewhere in this volume,16 we saw that among the neo-platonists there were two types of Achilles Arguments; one relies on the unification of representation, another focuses on self-knowledge. Proclus in particular argued that self-knowledge requires a simple subject: self-knowledge is a kind of ‘reverting on oneself,’ and this requires ‘both elements becoming one – both the reverted subject and that on which it has reverted. But this is impossible for a body, and, in general, for any divisible substance’ (Proposition 15). But in the above quote Clarke immediately makes clear that he is not focused on consciousness in the strict sense: he writes that the argument shows that thinking in general requires an immaterial subject – again without, alas, explaining why. Indeed, later he writes that he does not need to explain what consciousness is because ‘Every Man feels and knows by Experience what Consciousness is, better than any Man can explain it: Which is the Case of all simple Ideas’ (W III 790). It is tempting to think that what moves Clarke is the Achilles Argument proper: unification of representations requires a simple subject. And an important line of thought in his letters suggests as much. Thus he writes that his own consciousness is ‘truly one undivided Consciousness, and not a multitude of distinct Consciousnesses added together’ (W III 784). Collins never contests this claim, and Clarke does not volunteer to explain it. Their disagreements are focused elsewhere. Clarke offers this claim when he explains an important implicit premise of his Achilles Argument, which I will call the Homogeneity Principle – a principle also cited by Kant in the Second Paralogism account of the Achilles Argument. Here is a statement of this principle by Clarke: . . .it is evident at first sight, that every Power or Quality that is or can be inherent in any System of Matter is nothing else than the Sum or Aggregate of so many powers or qualities of the same kind, inherent in all its Parts. The Magnitude of any Body is nothing but the Sum of the Magnitudes of all its Parts. Its Motion, is nothing but the Sum of the Motions of all its Parts. And if Cogitation in like manner could possibly be a Quality really inherent in a system of matter, it must likewise necessarily be the Sum and Result of the Cogitations of the several Parts: and so there would be as many distinct Consciousnesses, as there are Particles of Matter, of which the System consists; Which I suppose will be granted to be very absurd. Compositions or Divisions of Magnitude, varied in infinite manners to Eternity, can produce nothing in the whole System no Quality or Power whatsoever but mere Magnitude. (W III 759)

Clarke thinks that a genuine quality must be the sum of qualities of the same kind if its subject is composite. There are types of qualities, or rather so-called qualities, to which this principle does not apply (W III 759–760), but he thinks that consciousness is a genuine quality that inheres in a subject and so if consciousness belongs to a composite subject, each and every part of that subject is conscious. That consequence is absurd, he claims. Collins agrees that it is (W III 806). Indeed, instead of explaining what about consciousness implies that it cannot be the sum of a multitude of consciousnesses Clarke repeatedly simply focuses on the absurdity of there being a multitude of consciousnesses corresponding to the 16

See the chapter by Devin Henry.

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multitude of material particles. Thus in his third letter Clarke writes that he takes Collins’ acceptance of the absurdity of this claim to indicate his acceptance of the idea that consciousness is an individual power, that is, it is ‘really One and not Many’ (W III 784). And in his second letter he had written: And if Cogitation in like manner [in the same way as motion and magnitude] could possibly be a Quality really inherent in a System of Matter, it must likewise necessarily be the Sum and Result of the Cogitations of the several Parts: And so there would be as many distinct consciousnesses as there are particles of Matter, of which the System consists; Which I suppose will be granted to be very absurd.17

So Clarke never explains what about consciousness entails that his consciousness can’t be the sum of a multitude of consciousnesses. One might be tempted to conclude from the above that Clarke really only objects to there being a multitude of conscious material particles, not so much to consciousness being a composite of consciousnesses of distinct parts. But I do not think this interpretation is right. One reason is this: as I noted above, Clarke inferred from Collins’ rejection of the possibility of a multitude of conscious material particles that Collins regarded consciousness as an individual power. This inference requires that it is something about consciousness itself that makes this possibility absurd, rather than just the oddity of a swarm of conscious material particles. And later we will see another context where this issue arises: to Collins’ puzzlement, Clarke holds that the soul is extended, but he insists that the soul thinks as a whole rather than in virtue of parts and again insists that consciousness can’t be a composite of consciousnesses (W III 843). So Clarke does not explain why consciousness cannot be composite in this sense. He may have the unification of representations in mind; but he does not become explicit about this. Given his failure to bring up the issue of unification when prompted to explain what consciousness is and why it requires an individual subject we cannot be sure that this is what he had in mind. Furthermore, since he claims that he does not really need to explain what consciousness is, and that we know from experience what consciousness is and that it cannot be explained, he may simply think that it is obvious from experience that one’s consciousness is not a composite of distinct consciousnesses.18 I must confess, however, that I wish he had explained just what feature of consciousness requires a simple subject; this would have made his position more satisfying. Furthermore, if one conceives of the Achilles Argument as essentially involving a claim about unification of representations, then strictly speaking Clarke does not offer an Achilles Argument. But he does offer something close to it, relying on the Homogeneity Principle: 17 W III 759, emphasis added. In this passage Clarke writes about the absurdity of the idea that all the parts of the conscious subject are conscious. But Clarke’s line of reasoning in his initial statement of the Achilles Argument presents a stronger version of the problem: he claims that the possibility of a material conscious being requires that matter would have to be essentially conscious and so all matter would be conscious (W III 730). He never explains the claim that matter would have to be essentially conscious, nor does Collins ask him about it. 18 As Lorne Falkenstein pointed out to me.

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(1) Consciousness cannot be the sum of a multitude of consciousnesses. (2) If consciousness belongs to a composite subject, that is, a subject that is not simple and consists of parts and not an individual being, it is a multitude of consciousnesses. (3) Consciousness can only belong to an individual being, that is, a simple subject. Collins does not prod Clarke further about what feature of consciousness rules out that it can be the sum of a multitude of consciousnesses and he does not argue for the view that it can. In his initial response he did ask Clarke why matter could not ever constitute an individual subject, which is the subject of the next section. And he pursues at length in the correspondence the possibility that the consciousness of a composite subject might instead result from, that is, emerge from, other, material qualities that belong to the parts of a composite subject. Both Clarke and Collins understand emergentism (which I will leave aside in this paper) to avoid the absurdity of the multitudes of material particles are conscious. Clarke answers that proposal using the Homogeneity Principle and by arguing that material qualities fail to be of the same kind as consciousness.

9.4 Matter One of Collins’ main lines of objection to Clarke’s argument is that he sees no problem with the possibility of matter constituting a genuine individual, something suitably unified so that it can be the subject of a single consciousness. I want to turn now to the treatment of matter in the correspondence, an issue that is very important to the Achilles Argument although rarely the focus of its attention. The crucial point is this: when the argument is used to rule out the possibility of a material thinking subject it requires that a material being cannot have the requisite type of unity. We saw that in his initial statement of the argument Clarke insisted that matter cannot be unified so as to constitute a genuine individual: For Matter being a divisible Substance, consisting always of separable, nay of actually separate and distinct parts, ‘tis plain, that unless it were essentially Conscious, in which case every particle of Matter must consist of innumerable separate and distinct Consciousnesses, no system of it in any possible Composition or Division, can be any individual Conscious Being; For, suppose three or three hundred particles of Matter, at a Mile or any given distance one from another; is it possible that all those separate parts should in that State be one individual Conscious Being? Suppose then all these particles brought together into one System, so as to touch one another; will they thereby, or by any Motion or Composition whatsoever, become any whit less truly distinct Beings, than they were when at the greatest distance? How then can their being disposed in any possible System, make then one individual conscious Being? (W III 730)

Collins is not convinced: Why may not several Particles of Matter, when united in one System, become an Individual Being, and be by the Power of God rendered incapable of any Division or Separation by Natural Causes, and consequently be a Subject capable of Thinking? If several Particles

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of Matter can be so united as to touch one another, or closely to adhere; wherein does the Distinctness or Individuality of the several Particles consist? (W III 751)

In response Clarke considers the possibility of an indivisible, in his words, indiscerpible, particle of matter that thinks. He says that such a thinking being would be naturally immortal, and that is what was at issue. But, he continues, such a particle of matter would not be possible: ‘For it is necessarily included in the Nature of Solid Substance, how small soever it be conceived to be, to consist still of Parts not essentially connected, and not at all depending on each other for their Existence.’ (W III 761) God could divide any particle of matter. Clarke and Collins seem to have a fundamental disagreement about the nature of matter. What is the source of this disagreement? Clarke accepted a conception of matter that he shared with Descartes and Leibniz and many others in this period. According to this conception of matter, it consists of actually distinct parts that do not depend on each other for their existence. Thus Descartes thought of matter, extended substance, as infinitely divisible, and he regarded all its parts as really distinct from one another. Each part exists in its own right, and does not depend on others for its existence and so all parts of matter are separable. Given that the parts of matter are really distinct, matter consists of actually distinct parts.19 Clarke’s argument that bringing the parts of matter close together so that they touch does not result in an individual being is strikingly similar to an argument Leibniz offered. Leibniz argued that the proximity of material objects does not result in genuine unity, the kind of unity Leibniz thought is necessary for something being a substance: For suppose that there are two stones, one for example the diamond of the Great Duke, the other that of the Great Mogul. One could impose the same collective name for the two, and one could say it is a pair of diamonds, but one could not say that these two diamonds constitute a substance. More or less does not make any difference here. Even if one brings them closer to one another and makes them touch, they will not be substantially united. Suppose that after they touch one joins another body to them capable of preventing their separation, for instance, if they were set in a single ring, all this would only make them an accidental being – unum per accidens. (G II 76, AG 79)

So Leibniz thinks that united parts of matter fail to constitute a substantial unity just as much as scattered parts do. Leibniz does not phrase his argument in the same terms as Clarke: Leibniz uses the notion of substance, Clarke does not. But elsewhere Clarke does use this notion while arguing that matter cannot think because

19 This is not an uncontroversial interpretation of Descartes. It follows, however, from (1) the real distinction of all the parts of matter as stated in Principles I.60, in combination with (2) Descartes’s claim that real distinction is a distinction between substances and (3) an understanding of substances as not merely separable but actually distinct beings each of which exists in its own right. So the real distinction of the parts of matter does not merely mean that they can exist apart but it means something about their actual mode of existence. Each part of matter actually is a distinct being that exists in its own right. For discussion of Descartes’s notion of real distinction see my Descartes’s Dualism, Ch. 1, pp. 3–8.

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it lacks the requisite type of unity: ‘No matter is one substance, but a heap of substances. And that I take to be the reason why matter is a subject incapable of thought.’20,21 But Collins simply does not see the point: why can’t a chunk of matter be an individual being, what’s lacking in its unity if the parts touch? Clarke does not offer an explanation and the deeper source of their disagreement does not become explicit. Part of Clarke’s motivation is clearly that he thinks of matter consisting of actual parts; this is why it cannot be the subject of consciousness as it would result in a multitude of consciousnesses. This was, as I noted above, a very common view in the period. The difficulty is then how to explain the unity of a piece of matter: what can unify the parts of matter into a genuine individual or substance? Clarke and Leibniz thought nothing could. One way to reject Clarke’s position is by arguing that matter does not consist of actually distinct parts. A minority of philosophers in the period rejected the actual parts doctrine, and held that a piece of matter has potential parts only.22 Matter may be infinitely divisible (the disagreement with the atomists is another matter), but it does not consist in actual parts. Parts arise as a result of actual dividing up and separating, or, according to some, by dividing in thought. Initially it seems as if Collins does not accept the actual parts doctrine. Thus he writes: ‘If several Particles of Matter can be so united as to touch one another, or closely to adhere; wherein does the Distinctness or Individuality of the several Particles consist?’ Once particles are united so that they touch, this question by Collins suggests he thinks they have lost their distinctness. On that view, a piece of matter may well be a unitary being, Clarke to the contrary. And then couldn’t matter be the subject of thought? However, later Collins expresses agreement with the actual parts doctrine (W III 769, 772). So this is not why he envisions that matter could constitute an individual being. 20

‘The Answer to a Sixth Letter Being part of a letter written to another gentleman,’ in A Demonstration of the Being and Attributes of God And Other Writings, Ezio Vailati ed., Cambridge University Press, 1998 (DBAG), p. 116. 21 Leibniz’s discussions of matter bring out an important point: the above argument addresses the Cartesian conception of matter where the essence of matter consists in extension and nothing more. Leibniz argued that on that conception matter cannot be a substance because it lacks the requisite unity. He also argued that there must be something underlying extension in order for matter to be real, there must be something that is extended: extension cannot constitute the nature of substance, and so cannot be the fundamental level of reality (See for instance, letter to de Volder, 24 March/3 April 1699, G II 169–170/AG 261). Leibniz proposes soul-like entities – substantial forms, and later in his life, monads – to do the job. Clarke and Collins are working with the Cartesian conception of matter Leibniz criticizes, although they often adopt a Lockean formulation: matter is solid substance. 22 For extensive discussion see Thomas Holden, The Architecture of Matter, Oxford: Clarendon Press, 2004. Collins expresses puzzlement over Clarke’s claim that matter is both divisible and ‘consists of actually separate and distinct Parts’: the latter description suggests that matter is actually divided, why add that it is divisible, Collins asks (W III 751)? This description of matter is confusing, perhaps, but not uncommon in the period. For discussion, see Holden, pp. 75–131, especially pp. 106–108 where he discusses an argument to the effect that actual separation of parts ‘is only possible if those parts exist as distinct entities in the first place.’

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Collins not only suggests that a piece of matter may be an individual being, but also that he does not see why it could not be ‘by the Power of God rendered incapable of any Division or Separation by Natural Causes, and consequently be a Subject capable of Thinking.’ Collins’ remarks implicitly raise the following question: what is the problem for thinking matter, according to Clarke? Is the problem (1) that matter has actually distinct parts, or (2) the modal idea that these parts could be separated? The questions are closely connected for Clarke as for him the sense in which matter has actual parts involves the idea that the parts can be separated. Unlike matter, space does not have real parts because its parts cannot be separated even in thought. But two different questions arise for the question whether matter can think. Clarke clearly sees problems on both counts: matter having actually distinct parts is a problem because the Homogeneity Principle requires that the consciousness of a composite subject be the sum of the consciousnesses of its parts and this is not acceptable. In addition, he addresses the modal problem when he argues that if the parts of a divisible subject of consciousness were separated, by the power of God, there is no acceptable way to answer the question what happens to the consciousness of the original whole (W III 761). Collins’ proposal that God might make the parts of matter inseparable directly addresses only the modal issue, not the non-modal problem. But Clarke thinks that matter is inherently divisible into separable parts and rejects Collins’ suggestion that God can make it indivisible: For it is necessarily included in the nature of Solid Substance, how small soever it be conceived to be, to consist still of Parts not essentially connected, and not at all depending on each other for their Existence. So that it is absolutely impossible and contradictory, to suppose any Particle of Matter so truly an Individual, but that by the Power of God (for the Powers of Nature here are nothing to the purpose) it may be divided into two or more Particles, which shall each of them separately be as Perfect and Compleat Matter, and continue to have all the very same Properties, as the whole Particle had before it was divided. (761, emphasis added)

Clarke’s response is puzzling, at least at first sight, in view of his stated goal to defend natural immortality: he now claims that the ‘Powers of Nature here are nothing to the purpose.’ And doesn’t Clarke’s claim that matter will always be divisible by God leave open the possibility that God might make matter indivisible by natural powers and so be naturally immortal in a sense? But in fact this sense of natural immortality would not do for Clarke. He had said that thinking of God as making the souls of people destined for hell immortal such that they can suffer eternally is unacceptable. What matters is that the immortality of the soul should not be the result of an act of God but of its own nature, and so this should rule out God making the soul indivisible. But there is a further problem: Clarke’s view seems to be that matter is always divisible by God, but there are particles that cannot be divided by natural powers.23 But if so, then he seems to allow for naturally immortal particles of matter. If only

23

Collins reports Clarke as holding this view (W III 774), and the quote above suggests it.

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God can divide such a particle, how is it any less naturally immortal than Clarke’s naturally immortal indiscerpible soul, which depends on God for its existence and so can be annihilated by God? Most of the discussion focuses, however, not on immortality and the modal question of divisibility, but on whether matter can think and Clarke’s view about matter as inherently composite and consisting of actually distinct parts: it follows, he thinks, that if a subject of consciousness is material, it contains a multitude of consciousnesses. Collins also rejects this idea, so his conception of matter and consciousness must allow for consciousness to belong to a chunk of matter in such a manner as to avoid this result. He needs to hold that consciousness can belong to a material subject as a whole, as a single individual subject, as Clarke would say, and not in virtue of each of the parts being conscious. Developing such a view requires more than denying Clarke’s view that matter essentially consists of actual parts. For instance, it seems right that the magnitude of a body is the sum of the magnitudes of its parts, whether or not one thinks of the parts of matter as actual or merely potential. But things must work differently for consciousness and so Collins has to explain why and how. In the end, however, Collins develops his materialism not by defending the possibility of a material individual subject, but by turning to the scenario on which consciousness emerges from material qualities, a scenario which he envisions does not require that the parts of the material subject are conscious or that they acquire the right sort of unity to count as an individual subject.

9.5 The Extended Soul Clarke’s position is complicated by the fact like Newton and Henry More he held that spiritual substances including God and the human soul are extended. As he explains to Leibniz, Clarke thinks that interaction with the body requires the soul to be extended.24 So Clarke must allow for a sense of extension for the soul that does not entail that the soul has parts each of which is a distinct subject of consciousness. Collins expresses puzzlement about this: doesn’t extension entail parts and divisibility at least by God (W III 775)? Clarke explains that the sense of extension is different for the soul, it is not partes extra partes, a phrase common in scholasticism for describing the extension characteristic of bodies (W III 762). The extension of the soul is instead like the extension of space, Clarke argues. He contends on various occasions in his writings that the parts of space are dependent on one another, they are not separable even in thought, unlike the parts of matter. Thus he writes to Leibniz:

24

Clarke, Works III, 11–12. For discussion see Ezio Vailati, ‘Clarke’s Extended Soul,’ (Journal of the History of Philosophy, 31, 1993), pp. 388–390. Clarke appeals to the need for a substance to be where it acts seeing the alternative as action at a distance.

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For infinite space is one, absolutely and essentially indivisible. And to suppose it parted is a contradiction in terms, because there must be space in the partition itself, which is to suppose it parted and yet not parted at the same time. (G VII 368/L 685) Parts in the corporeal sense of the word are separable, compounded, ununited, independent on and movable from each other. But infinite space, thought it may by us be partially apprehended, that is may in our imagination be conceived as composed of parts, yet those parts (improperly so called) being essentially indiscernible and immovable from each other, and not partiable without an express contradiction in terms . . ., space is in itself essentially one and absolutely indivisible. (G VII 383–384/L 693).

So the independence and separability of the parts of matter is crucial and distinguishes them from spatial parts. Similarly then, the soul, while extended, does not have separable parts. Collins finds the analogy with space unsatisfactory on two grounds: space is infinitely extended and it is the absence of bodies, whereas the immaterial substance that is the soul is finite and it is really something. He contends that the idea that space is not a real being or substance is illustrated by the fact that it cannot be acted upon (W III 814). Clarke responds that the infinity of space is not relevant; it does not explain why the parts of space are interdependent, the reason lies in ‘the contradiction which a separation of them manifestly would imply’ (W III 794). Indeed, it seems right that we cannot even in thought separate the parts of space in the sense that we cannot imagine parts of space being separated. Furthermore, while he does not say so to Collins, Clarke also rejected the idea that space is nothing, as the following reply to Leibniz suggests. He writes that those who accept the Leibnizian view that. . . .space is nothing but a relation between two bodies are guilty of the absurdity of supposing that which is nothing to have real qualities. For the space which is between two bodies is always unalterably just what it was and has the very same dimensions, quantity and figure whether these, or any other bodies be there, or anywhere else or not at all . . .(DBAG 114–115)

How well has Clarke explained the difference between space and matter with respect to their having parts in view of his position that the soul is extended in a sense that allows it to be a subject of thought? It is fairly clear in what sense Clarke wants to say matter has parts but space does not in the modal sense. His claim that the parts of matter are, but the parts of space are not separable even in thought addresses the modal question of the divisibility of matter and thus immortality. But what of the non-modal question? Does Clarke’s analogy with space give us a sense of extension for the soul that rules out that it has parts each of which will have to be conscious in virtue of the Homogeneity Principle? Intuitively it would seem that space does have actual parts in a sense relevant to that issue, even if they are not separable. For my chair is in one part of space, my desk in another. If the soul is extended in the sense in which space is, would it not have parts in a sense that raises the worry about a multitude of consciousnesses just as in the case for the parts of a material subject? Collins does not raise this question, but Clarke offers several remarks that in fact address it. For the soul, he suggests, one must conceive of a substance created by

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God that is without separable parts and essentially one. And most clearly to the point he claims that the soul is the subject of each mental state as a whole (W III 843).25 Similarly he writes about space: The immensity of space, it being throughout absolutely uniform and essentially indivisible, is no more inconsistent with simplicity than the uniform successive flowing of the parts of duration, as you most rightly observe, are inconsistent with simplicity. (DBAG, 116)

Clarke here adduces an analogy with time that he brings up repeatedly, and which, I must confess, I find quite unhelpful.26 But the useful point in this quote is the point that space is absolutely uniform: it is undifferentiated by qualities – in some sense. For on the other hand, his claim to Leibniz that a part of space does have ‘dimensions, quantity and figure’ suggests that he thinks space is differentiated by qualities in some sense. So perhaps the solution is to say that there are distinctions among qualities in relation to space: to put it simply, space is subject to various primary qualities in the Boylean sense (although not, of course, motion). But perhaps Clarke could distinguish between the qualities space does have, size, shape, and ones it does not have, ones that would make it lose its qualitative uniformity. It makes some intuitive sense to say that variations in size for spaces is compatible with some sort of qualitative uniformity. Indeed, matter was commonly thought in this period to have primary qualities but otherwise be qualitatively uniform. At the same time, a difference between space and the soul might be a problem here: space seems to be qualitatively uniform because it is arguably free of qualities other than the primary ones. But the soul is supposed to have conscious states. So the analogy is imperfect. Furthermore, Clarke writes that God’s individual consciousness has no size (you can’t speak of ‘an ell or a mile of consciousness’). But the analogy with space, and Clarke’s view that the soul must be extended in view of interaction suggests that the soul does have a size, even if its parts are not separable. Collins asks: if the soul is extended could not God vary its size (W III 775)? And then if the soul thinks as a whole its thought would have the same size in the same (perhaps non-literal) sense in which the redness of an apple would seem to have a size. That seems distinctly odd. Perhaps this is pushing the analogy with space too far. Perhaps its usefulness is exhausted by a more limited goal: rather than demonstrating the precise sense in which the soul is extended, perhaps the extension of space can demonstrate that it is possible for something to be extended without having actual, separable parts. Needless to say, however, Clarke’s view that the soul is extended remains fairly unclear. Indeed, Clarke is not blind to the fact that there are difficulties. At one point he writes in response to Collins’ questions about the soul being extended: I take it to be demonstrated, that the Soul is an immaterial indiscerpible Substance: . . .But conceiving Immateriality not to exclude Extension, and supposing the Difficulties arising from that Hypothesis to be such as could not be clearly answered; yet this would not weaken the foregoing Proof, unless that Argument could otherwise be shown to be in itself defective.

25 26

See also ‘The Answer to a Sixth Letter,’ DBAG, 116. For discussion see Vailati, ‘Clarke’s Extended Soul.’

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For there are many Demonstrations even in abstract Mathematicks themselves, which no Man who understands them can in the least doubt the Certainty of, which yet are attended with difficult Consequences that cannot perfectly be cleared, The infinite Divisibility of Quantity, is an instance of this kind. (W III, 794)

He adds God’s eternity ‘than which nothing is more self-evident’ and God’s immensity as other examples. While holding that the soul is extended, Clarke seems to express here a deeper attachment to the immateriality and indivisibility of the soul. And he contends that things are no better if one supposes the soul to be unextended. Either way, he suggests there are questions we cannot answer, an appropriate expression of humility.27

9.6 Conclusion In sum, Clarke offers a version of the Achilles Argument that focuses on the second half of a Broad Achilles, and argues from the requirement of what he calls an individual subject to the immateriality of the soul. He begins the correspondence aiming to defend the natural immortality of the soul, but the discussion with Collins focuses on its immateriality. In defense of the need for a simple subject of consciousness, Clarke does not talk about the need for unification of representations, or, as Proclus did, on self-knowledge. He leaves us in the dark about just what about consciousness requires a simple subject, claiming merely that consciousness cannot be the sum of a multitude of consciousnesses. He does not say why, thinking perhaps that this is obvious, and Collins does not question this claim. The correspondence contains more on the question of the nature of matter – as well as a lengthy discussion of emergentism, which I leave for another occasion. Collins questions Clarke’s claim that matter cannot be an individual subject. While some thinkers in the period would reject Clarke’s view that matter consists of actually distinct parts, Collins does not endorse that position, and so he does not make clear how a material entity could have the sort of unity required for an individual subject. I have discussed their exchange on this issue at some length. I hope this discussion highlights a fact easily ignored about the Achilles Argument; it is tempting to focus on what views about the nature of the mental support the Achilles, but assumptions about the nature of matter are just as important for the argument.

27 Lest the reader, partial to Collins’ position, rashly take his side on this particular point, Collins promptly misunderstands Clarke’s admission. Clarke raises questions he could not answer, Collins takes this to be an admission of ‘Contradictions and Absurdities’ in Clarke’s position (W III 814). Clarke’s responds that this misrepresents what he had said (W III 849).

Chapter 10

Leibniz’s ‘Achilles’ Jean-Pierre Schachter

It was incumbent on writers of the 17th C. to comment on and prove the immortality of the soul. Many of them appealed to an argument that had been in existence in various forms since antiquity, an argument that ultimately attracted the respectful attention of Kant, who dubbed it ‘the Achilles of all dialectical inferences.’1 In very general terms, the argument sought to infer, first, the indivisibility of the soul, and then its immortality, from the experienced unity of consciousness. In this paper, I address the question of whether the arguments that Leibniz used to establish the immortality of the soul belong to the Achilles family. As a preliminary, I examine the argument type and set its defining conditions.

10.1 What is an ‘Achilles’? An Achilles, in very general terms, is first an argument that hypostasizes, that is, it seeks to establish the existence of something that is directly inaccessible by means of an inference. Second, the directly inaccessible something it hypostasizes is a ‘simple’ or indivisible substance, which, by virtue of being simple, is then further inferred to be immaterial. Third, it attempts to do this on the basis of experiential data consisting of various kinds of ‘unity’ discoverable in our experience, namely (a) the unity of multiple distinct perceptions in a single subject, (b) the unity of multiple ideas in a judgment, and (c) the unity present in and underlying self-awareness. And fourth, it infers that a simple substance must exist because our unified experience demands an indivisible subject (rather than the existence of indivisible objects). For an argument to satisfy the Achilles template, it is not sufficient that it somehow make reference to the unity of consciousness; rather, it must use the unity of consciousness J.-P. Schachter Department of Philosophy, Huron University College, The University of Western Ontario, 1349 Western Road, London, Ontario, Canada N6G 1H3 Phone: (519) 438-7224 e-mail: [email protected] 1 Immanuel Kant Critique of Pure Reason, trans. by Norman Kemp Smith (NewYork: St. Martin’s Press, 1965), A351.

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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as the ground for an inference to a simple substance that is the subject of experience. I will take these requirements to constitute conditions that must be satisfied for an argument to qualify as an Achilles. In summary, an Achilles argument must meet the following four conditions: 1. 2. 3. 4.

It must hypostasize, It must be premised on the existence of the unity of consciousness, It must conclude that an indivisible immaterial substance exists, and It must reason that the existence of the unity of consciousness requires that an indivisible immaterial substance exists as a subject of experience.

The earliest clear statement of the argument seems to occur in Plotinus, who also introduces an associated metaphor that is to recur numerous times in the argument’s history, the metaphor of the convergence of radii at the center of a circle: It is clear from the following that, if the soul were a body (soma), there could be no perception. . . . If something is going to perceive anything, it must itself be one and must take hold of it (antilambanesthai) in one act, both if several impressions are [perceived] through many sense-organs, or many qualities [are perceived] in one object, or if one senseorgan [perceives] a complex object, for example, a face. For there isn’t one [perception] of the nose, and another of the eyes, but one identical [perception] of all of them together. And if one [sense-object] enters through the eyes, and another through the hearing organ, there must be some one thing to which they both go. Otherwise, how could we state that they are different from each other, if the sense-objects did not all come together to one and the same [percipient]? Therefore, this [unified percipient] must be like a center point, and the perceptions coming from all places, like the lines coming from the circumference of the circle, must terminate there. And what takes hold of these must be of this kind, truly one.2

Is there, then, an Achilles in Leibniz? One very attractive candidate is the argument included in The Confession of Nature Against Atheists, 1669 (Gerhardt IV, 105–110), part II, entitled ‘The Immortality of the Human Mind, Demonstrated in a Continuous Sorites.’3 B.L. Mijuskovic4 includes the Sorites argument in his history of the Achilles, stating of Leibniz that ‘In an exceptionally thorough form of the argument, he produces possibly the most perfect formulation of the proof.’ A closer look at the Sorites argument reveals that it does not satisfy requirement #2, that of reasoning from the unity of consciousness, and so does not qualify as a ‘most perfect formulation of the proof.’ Nonetheless, it is a close relation of the Achilles and provides clues for the discovery of an authentic Achilles in Leibniz’s mature philosophy.

2

From a new translation by Devin Henry. See Chapter 3, this volume. Leroy Loemker, Gottfried Wilhelm Leibniz: Philosophical Papers and Letters (Chicago: University of Chicago Press, 1956) v. I, p. 174. Hereafter cited as LL. Cited in Ben Lazare Mijuskovic, The Achilles of Rationalist Arguments (Hague: Martinus Nijoff, 1974). Hereafter, BLM. 4 BLM, Op. cit. 3

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10.1.1 The ‘Sorites’ Argument Here is the Sorites in Leibniz’s own text with numbering of argument lines added and with justifications separated: 1. The human mind is a being, one of whose actions is thinking. 2. If one of the actions of a being is thinking, one of its actions is immediately perceptible, without supposing parts in it. For thought is (1) a thing that is immediately perceptible, mind being immediate to itself when it perceives itself thinking. (2) Thought is a perceptible thing without awareness of parts. This is clear from experience. For thought is that ‘something, I know not what’ which we perceive when we perceive what we think. But when, for example, we perceive that we have thought of Titius, we not only perceive that we have the image of Titius in our mind, for this has parts, of course; such an image is not enough for thinking. For we have images in the mind even when we do not think of them, but we perceive, besides, that we have been aware of this image of Titius, and in this awareness of our images itself we find no parts. 3. Assume a being performing a certain action which is immediately perceptible, without a perception of its parts. Then this certain action is a thing without parts; 4. For a quality immediately perceived in a thing actually belongs to it, since: the cause of error is the medium, for if an object of perception were the cause of error, it would always be perceived falsely; if the subject were the cause, it would always perceive falsely. 5. If something has for one of its constituents a thing without parts, then one of its actions must be other than motion; For all motion has parts, by Aristotle’s demonstration and common agreement. 6. A being whose action is not motion is not a body; For all bodily action is motion, since every action of a thing is a variation of its [sic] essence, and the essence of a body is being in space. 7. But motion is a variation of existence in space. 8. Therefore every action of a body is motion. 9. Whatever is not a body is not in space; for to be in space is definition of a body. 10. Whatever is not in space is not movable, for motion is change of space. 11. Whatever is immovable is indissoluble, for dissolution is the motion of a part. 12. Everything indissoluble is incorruptible, for corruption is internal dissolution. 13. Everything incorruptible is immortal, for death is corruption of the living, or dissolution of its fabric, through which self-moving things obviously move themselves. 14. Therefore the human mind is immortal. Q.E.D.5 Despite its length, the argument is intuitively quite simple. The mind thinks; its thinking is directly perceptible by it; and what it then perceives is something that has

5

LL, ibid.

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no parts. Therefore, thinking is without parts. Anything that is capable of an action that has no parts, is capable of an action that does not involve motion. Anything capable of an action that does not involve motion, is not a (material) body. Anything that is not a body, is not in space. Anything that is not in space, is immovable. Anything that is immovable, is ‘indissoluble’ (simple). Anything that is indissoluble, is immortal. What distinguishes the Sorites from the Achilles as I defined it earlier is the special role that simplicity plays. In the Achilles thus defined, we reason from the fact that the soul unifies a perceived plurality to the soul’s simplicity. In the Sorites, we reason from the fact that we perceive a simple property incompatible with plurality in the soul, to the soul necessarily being simple. The simple property is, of course, the soul’s capacity for a simple action, namely that of thinking: I think, therefore I perform a simple action, therefore I do something that does not involve motion, therefore I am not in space, therefore I am immovable, therefore I am indissoluble. While in the Achilles, we reason from the fact that the distributed image of Titius is available to us as a single image, in the Sorites, we reason from the fact that our act of thinking Titius is itself ‘without parts.’ In the Achilles, the point of departure is the object of thought, while in the Sorites, the point of departure is the act of thought. Noteworthy is the central role that self-awareness plays in the proof, a notion that will take front stage in his later philosophy under the name of ‘apperception’. While not quite an Achilles, the Sorites is instructive on where to look for the Achilles in the later Leibniz. It provides this clue in revealing in an early form one of Leibniz’s most fundamental later convictions, namely that (1) something simple must exist, and (2) that such a simple must have the character of an action, rather than that of a passive substance. The fact that motion exists together with the putative fact that matter is ‘passive’ prompted him to express the following position in 1695 about the only possible nature of the ultimate constituents of nature, a position that stayed with him until his very last writings: At first, when I had freed myself from the yoke of Aristotle, I was in favour of [material] atoms and the void, because this view best satisfies the imagination. But thinking again about this, after much meditation I saw that it is impossible to find the principles of a real unity in matter alone, or in what is only passive, since this is nothing but a collection or aggregation of parts ad infinitum. . . . So, in order to get to these real unities I had to have recourse to a formal atom, since a material thing cannot simultaneously be material and perfectly indivisible, or possessed of a genuine unity. So it was necessary to recall and, as it were, to rehabilitate substantial forms, which are so much decried these days. . . . I found, then, that the nature of substantial forms consists in force, and that from this there follows something analogous to feeling and desire; and that they must therefore be understood along the lines of our notion of souls.6

The ultimate constituents of nature are, then, necessarily non-spatial entities whose only existence conferring property is that of containing within themselves different

6

Gottfried Leibniz, A New System of the Nature and the Communication of Substances, as Well as the Union Between the Soul and the Body (1695), translated and edited by R.S. Woolhouse and Richard Francks (Oxford: Oxford University Press, 1997), pp. 11–12. Hereafter, NS. My emphasis.

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self-moved representative streams: Esse if and only if percipere. These representative streams are themselves extended or ‘distributed’. If we are to find an Achilles in the later Leibniz, it will be an argument that moves from the distributed nature of the represented object of ‘thinking’ to the existence of the Monad. I believe that we do find precisely this argument, but not in a localized form; in fact, the argument will turn out to be the foundation of the Leibnizian metaphysic. If this is correct, it helps to explain why the early Leibniz would entertain a separate argument of the Achilles kind, but seem to eschew it in his later philosophy. If I am correct, he does not eschew it at all, it is present, but it is concealed in plain view. The Achilles is incorporated into the doctrine of the Monadology.

10.1.2 The Monadology Argument (Sect. #2) Apart from the Sorites, the only other reason that Leibniz gives for believing that an immaterial substance exists is the one given in Sect. 2 of The Monadology (1714):7 2. And there must be simple substances, since there are composites; for the composite is nothing but an accumulation or aggregate of simples.8

The Monadology was written two years before Leibniz’s death in 1716, so it is worth pointing out that the argument of Sect. 2 appeared in his writing as early as 1667,9

7 Margaret Wilson thinks there is another one in part II of her ‘Leibniz and Materialism’ Canadian Journal of Philosophy (1972), pp. 495–513, though her representations of both Leibniz’s and Kant’s versions are unsympathetic. She finds the argument implicit in Leibniz’s windmill example in the Monadology, but not in his doctrine of the relation of composites and simples. However, while the windmill example is indeed an argument for the existence of a simple substance, it does not require an appeal to the unity of consciousness. All it requires as an argument is consent to the proposition that perceptions are not material, which Leibniz takes as given, for the conclusion to follow by disjunctive syllogism. Consider, for example, this passage from Leibniz’s New Essays:

Thought. . . . cannot be an intelligible modification of matter and be comprehensible and explicable in terms of it. That is, a sentient or thinking being is not a mechanical thing like a watch or a mill: one cannot conceive of sizes and shapes and motions combining mechanically to produce something which thinks, and senses too, in a mass where [formerly] there was nothing of the kind—something which would likewise be extinguished by the machine’s going out of order. So sense and thought are not something which is natural to matter, and there are only two ways in which they could occur in it: through God’s combining it with a substance to which thought is natural, or through his putting thought into it by a miracle. (New Essays on Human Understanding, Ed. P. Remnant and J. Bennett [Cambridge: Cambridge University Press, 1982], pp. 66–67.) It is for this reason that I prefer to locate the Achilles in Sect. 2. 8 Gottfried Leibniz The Monadology, in Nicholas Rescher G.W. Leibniz’s Monadology: An Edition for Students, (Pittsburgh: University of Pittsburgh Press, 1991), p. 17. 9 He already states this position in 1667 in correspondence with Arnauld, see LL, v. I, p. 527.

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two years before the Sorites argument, and was restated in 169510 and 1704,11 as well as in the Principles of Nature and of Grace,12 which was written at the same time as The Monadology. This implies that this key notion in the later philosophy was already in place at the time of the Sorites and was underlying it. In each of the places cited, the argument is presented as an enthymeme, and it is far from clear what the suppressed premises are. On the face of it, there are a number of reasons to think that it must be an Achilles. One is that the Achilles had been considered since Plotinus a powerful and near standard argument against materialism. Leibniz had a need for such an argument, was aware of its existence, and even defended it against Locke.13 It would be odd, therefore, if he not only did not use the argument, but nowhere explained its rejection. In addition, Sect. 2 asserts that the existence of a ‘composite’, which seems minimally to be some kind of unified aggregate, entails the existence of a ‘simple’, which suggests the Achilles. Finally, that it is, is suggested by the following passages in which a variant of the Plotinus metaphor occurs: Mr. Locke asks if an indivisible and unextended substance can have at the same time modifications different and even relating to inconsistent objects. I reply, Yes. That which is inconsistent in the same object is not inconsistent in the representation of different objects, conceived at the same time. It is not therefore necessary that there be different parts of the soul, as it is not necessary that there be different parts in a point although different angles come together there.14 (c. 1708)

and The simplicity of a substance does not prevent the plurality of modifications which must necessarily be found together in the same simple substance; and these modifications must consist of the variety of relations of correspondence which the substance has with things outside. In the same way there may be found, on one center or point, though it is perfectly simple, an infinity of angles formed by the lines which meet in it.15 (1714)

That he should appeal to this metaphor is no surprise, however, given that he writes in The Monadology:

10 A New System of the Nature and the Communication of Substances in LL, op. cit., v. II, p. 745. Cf. NS, op. cit., p. 23. 11 Leibniz, cited in Rescher (G II, 267; to de Volder [1704]), p. 50. 12 Leibniz, Principles of Nature and of Grace (1714), LL, v. II, p. 1033 (see Sect. 1). Hereafter, PNG. 13 Gottfried Leibniz, Remarks on the Opinion of Malebranche that we see All Things in God (1708), in P.P. Wiener Leibniz Selections (New York: Charles Scribner’s Sons, 1951). Locke had severely criticized Malebranche in his Examination of Malebranche (1693), and one of his arguments was that the Achilles, used by Malebranche, was as much an argument against a simple substance as an extended one. Leibniz rose to Malebranche’s defense in the above cited work. This was drawn to my attention by Prof. Thomas Lennon. 14 Ibid. p. 502, my emphasis. 15 PNG, LL, op. cit., v. II, p. 1034. Cited by Rescher, op. cit. My emphasis.

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12. But beyond the principle of change, there must also be an internal complexity (détail) of that which changes, which would produce, so to speak, the specification and the variety of simple substances. 13. This internal complexity (détail) must enfold a multiplicity in unity or in the simple. For as every natural change happens by degrees, something always changes and something remains. Consequently, there must be a plurality of properties (affections) and relations within a simple substance, even though it has none [i.e., no plurality] of parts.16

What remains unanswered is whether his argument in Sect. 2 meets conditions 2 and 4, that is whether he appeals to the unity with which the multiplicity is experienced as a ground for inferring the existence of a simple substance. On first review, the news is not good for the Achilles hypothesis.

10.2 The Reasons Against Leibniz’s argument seems reasonably clear and non-Achilles on first reading. There is text that seems to elaborate his thinking as follows: Since there are ‘composites’ in the world (whatever they are), there must be a substance of some kind. Whatever substance that might be, it cannot be divisible, because there is an insuperable a priori objection to the existence of a divisible substance. Since matter is divisible, the substance in question can’t be matter. The only other candidate for substance is mind or something like it, which is indivisible, and thus there must exist a mind-like substance, Q.E.D., which he calls a ‘Monad’. His reasoning seems to be that the reality of anything divisible must be a function of the reality of its component parts. However, if the parts are also divisible, then their reality must be a function of their parts. Unless there exist parts that are both real and indivisible, the regress towards a source for reality is infinite, reality is never found, and nothing can be real. Here is a typical instance of the text that leads to such an interpretation: . . . where there are only beings by aggregation, there are not even real beings, because every being by aggregation pre-supposes beings endowed with true unity, because it obtains its reality only from the reality of those of which it is composed, so that it will have no reality at all if every being of which it is composed is again a being by aggregation,- or else we must seek some other foundation for its reality, seeing that by this method it can never be reached, even by searching forever.17

Since matter is extended, it is infinitely divisible, and therefore cannot be real or a substance. Call this the ‘materialism regress interpretation.’ And so, the Leibniz argument seems quite remote from the Achilles. On the one hand, while the Achilles is based on exactly the same disjunctive syllogism as Leibniz’s argument, namely that there must exist an indivisible substance since matter won’t do, it concludes that there must be an indivisible substance because 16

Rescher, pp. 71–72. Leibniz, Letter to Arnauld (G II, 96–97, Ariew & Garber, p. 85, 1687). Cited by Rescher, op. cit., p. 48. 17

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(1) thought exists, (2) thought requires an indivisible substance, and (3) matter, being divisible, can’t be a host to thought. The Achilles rejects the material hypothesis on the ground that a material substance is incompatible with the unity exhibited in consciousness: it is an argument against Locke’s suggestion that matter might think. Leibniz, on the other hand, does not appeal to this reason in those terms. Instead, he seems to reject the material hypothesis on the metaphysical ground that a substance such as matter is a priori impossible because of his principle that only the indivisible is real (is capable of being a ‘substance’). This does not appear to be an Achilles argument. Construed the way of the materialism regress interpretation, the text seems to lead far away from the Achilles. The apparent issue in this interpretation is the very existence of matter, not whether matter could be a host to thought, the thinking matter hypothesis that is most inimical to the Achilles. Leibniz’s argument concludes that there must exist immaterial substance because material substance is impossible and one or the other must exist. The only purpose to the premise that specifically composites exist seems to be to establish that something exists, which only then leads to the reasoning about what sort of something this could be. The fact that the something is characterized as ‘composite’ seems incidental in this interpretation, since the reasoning to a simple substance does not seem to depend on it. Yet, the whole story has not been told and there is still hope for the Achilles hypothesis. In particular, the materialism regress interpretation does not explain why Leibniz argues specifically from ‘there are composites.’ To put it another way, it seems that the argument on the materialism regress interpretation could just as easily have been based on one’s own existence, rather than on the existence of ‘composites’. The argument would proceed thus: I exist. Anything that exists is either material or immaterial. I could not be material, because matter is infinitely divisible, and if I were material, I would not exist. Therefore, since immaterial substance is indivisible, I must be an immaterial substance. Putting it this way would even have had the advantage of a main premise that would have been taken as self-evident in the Cartesian context. The fact that arguing from ‘there are composites’ is unnecessary on the materialism regress interpretation suggests that it is a wrong interpretation because it fails to account for a part of the text that Leibniz repeatedly uses in his statement of the argument. A necessary condition for a satisfactory interpretation of Monadology Sect. 2 is that it account for ‘there are composites.’ This is not an easy requirement to satisfy. The problem is that Leibnizian ‘composites’ seem to be central to his argument and, at this point, we do not know what they are and certainly not their role in his argument. This is a vexing question in the interpretation of Leibniz for at least two reasons, one of which is that his usage of the words ‘aggregate’, ‘composite’, and ‘compound’ is often ambiguous, and the second of which is that it is likely that Leibniz changed his mind on the topics to which these words apply late in his life. If a plausible reading of ‘composite’ can be made out, however, it is still possible that the latent argument in Sect. 2 can also be discerned, and the Achilles within revealed.

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10.3 What is a ‘Composite’? When it comes down to it, there are only two serious possibilities for ‘composite’, (1) a collection per se of substances, without consideration of anything at all that might unify them in any sense, and (2) a phenomenally unified representation. In his pre 1709 writings, Leibniz allows only for phenomenal unification, the entities per se themselves never constituting more than an aggregate. It is true that there are good textual grounds for believing that he reconsiders this view during his extended correspondence (1709–1715) with Bartholomew Des Bosses. During this period, he apparently begins to allow for the possibility that combinations of indivisibles can have a unity and a reality of their own, possibly apart from their representation. He does this most explicitly in a letter to des Bosses18 in 1715, just one year after he wrote both The Monadology and The Principles of Nature and Grace, in which he clearly makes a distinction between (1) simples and composites, on the one hand (both of which are substance), and (2) ‘semi-substances’, on the other. Of the first two, he says that they have ‘unity per se,’19 and are ‘full beings’; of the third, he says that they have ‘unity by aggregation’ and are ‘semi-beings’ or ‘phenomena’. The significant change is that composites are for the first time included among ‘substances’ and are distinguished from mere aggregates. Nonetheless, the fact that the Monadology Sect. 2 argument for the existence of simples already appears as early as 1667 makes it extremely unlikely that it hinges on a conceptual shift that only makes an explicit appearance in 1715. I will therefore assume that this argument does not rely on the later view. Now, I have already given the metaphysical reason that persuades him that there cannot exist material substance, which is the principle that only the indivisible is real. It is this that makes him conclude that only indivisible substances are possible. He is also committed, however, to an implication of that principle, namely that aggregates of indivisibles do not have any ‘additional’ being for, being aggregates, they have only the being of their individual constituents. This is what he says in 1703: Since only simples are truly things, what remain are only entities by aggregation; to that extent they are phenomena, and, as Democritus put it, exist by convention and not by nature.20

And again in 1705: This unity of the idea of an aggregate is a very genuine one; but fundamentally we have to admit that this unity that collections have is merely a respect or relation, whose foundation lies in what is the case within each of the individual substances taken alone. So the only perfect unity that these ‘entities by aggregation’ have is a mental one, and consequently their very being is also in a way mental, or phenomenal, like that of the rainbow.21 18

See ‘Supplement to Letter XVI,’ Leibniz to Des Bosses (8/19/1715), LL, op. cit., v. II, p. 103. Loemker also notices the change in Leibniz’s account of substance in his reference on in v. II, p. 1034 (note 349, p. 1202). 20 Leibniz ‘Correspondence with de Volder,’ LL, op. cit. v. II, p. 864. Cited in Rescher. 21 Leibniz, cited in Rescher, (NE, p. 146). 19

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What he means by the word ‘idea’ in the above is nothing other than ‘representation’, and when he is speaking of the ‘unity of collections,’ he is speaking of the unity of consciousness. This view precludes collections of actual indivisibles per se having any reality other than that belonging to their elements. The mental representations of aggregates are unified, while their objective constituents are not, and these representations are what he often calls ‘composites’. For Leibniz, ‘unity’, ‘reality’, ‘substantiality’ all go hand-in-hand, and so, since aggregates cannot be per se ‘real’, neither can they be ‘unified’. In Monadology Sect. 2, Leibniz says both ‘there are composites’ and ‘the composite is nothing but an accumulation or aggregate of simples.’ This is true for Leibniz, but misleading because it suggests that the word ‘composite’ is really a synonym for ‘aggregate’, but not only does this not make sense in terms of his other accounts of those words, it makes the elaboration of Sect. 2’s argument impossible. It is true for Leibniz because the composite is not a substance; it is a kind of phantasm that exists only on the being ‘borrowed’ from a (simple) substance. On the other hand, a Leibnizian ‘composite’ can’t be an aggregate of Leibnizian substances because he uses the plural in a way that suggests that composites are distinct entities with persisting identities. The world of substances, however, has no principles that bind groups together into collections that have a corporate identities. Outside the inner world of a Monad, substances are indistinguishable and without any connection at all. It is only within a Monad that space and time exist and only there that the persisting identity of a group is possible. Consequently, ‘composites’ can’t be mere ‘aggregates’ of substances. While it is also true that in Leibniz’s system, the unified representation expresses the relations that exist across the inner perceptual lives of all of the members of its aggregate, and, thus, in a sense, the composite ‘is’ the aggregate, this is at the very best a figurative sense of ‘is’. This is what he writes to Bayle in 1702(?): . . . there must be simple beings, otherwise there would be no compound beings, or beings by aggregation, which are phenomena rather than substances, and exist (to use the language of Democritus) by nomos [convention] rather than physis [nature], that is, notionally, or conceptually rather than physically. And if there was no change in simple things’ there would be none in compound things either, for all their reality consists only in that of their simple things.22

A ‘composite’ is therefore phenomenal and retains its identity through changes in time. This makes sense of ‘there are composites’ for at least three reasons: (1) it is supported by Leibniz’s text, (2) it explains the use of the plural, and (3) it explains why it is asserted without proof, since as phenomenon, it is self-evident. This passage reveals that Leibniz’s argument is not the simple regress one I outlined earlier above. It is a regress argument, but not quite the one with which I began. The key lies in the expression ‘beings by aggregation,’ which are not, as it were, collections of substances; they are, rather, phenomenally unified representations of

22

Leibniz, Letter to Bayle, 1702? In Woolhouse and Francks, p. 129, my emphasis.

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collections of substances. Knowing this, we must reread the passage cited earlier in which the reasons for the inference to simple substances is given: . . . where there are only beings by aggregation, there are not even real beings, because every being by aggregation pre-supposes beings endowed with true unity, because it obtains its reality only from the reality of those of which it is composed, so that it will have no reality at all if every being of which it is composed is again a being by aggregation,- or else we must seek some other foundation for its reality, seeing that by this method it can never be reached, even by searching forever.23

This argument maintains that the existence of simple substances is a necessary condition for the existence for the existence of beings by aggregation, which is Leibniz’s phrase for phenomena, phenomena with identities that persist through time. What remains undecided are his referents for ‘composites’ or ‘beings by aggregation.’ As it was tempting to read his argument as no more than a vicious regress on materialism, it is also tempting to read his phenomenal ‘composites’ to be individual phenomenal ‘objects’. A phenomenal object is a phenomenalist’s object; it is a construction out of sense data that retains its identity through time. Thus, my laptop, understood in terms of the sensations that it provides me, is a phenomenal object, and it might seem that Leibniz is thinking of these as his ‘composites’. The tempting argument would then be, it is because I have phenomenal objects, that simples must exist. The clause that leads in this direction is this: ‘every being by aggregation presupposes beings endowed with true unity, because it obtains its reality only from the reality of those of which it is composed.’ The reason is that he uses the singular in speaking about the ‘being by aggregation’ and the plural when speaking of its constituents. Thus, he seems to be saying that the being by aggregation gets its reality from the members of the aggregate of Monads that it is representing. This suggests that his Monadology Sect. 2 argument is that we can infer the existence of an aggregate‘s simple constituents from our experience of them in the form of unified perceptual objects. I think this is wrong and that the passage is only rejecting the materialist hypothesis by reductio,24 but more on this later. Right now, it is enough to see that this is not the only possibility. There are two ways in which his inference could be read. We could interpret him, as above, as inferring that (1) the simples that make up the laptop aggregate must exist independently of their unified representation, or (2) that it is the solitary simple that is me and that unifies my body as well as my laptop representation that must exist. If we choose (1), then the argument is not an Achilles, and if we choose (2) it is. If it can be shown that it is Leibniz’s intention to argue towards the subject substance and not to the object substances, then this also

23 Leibniz, Letter to Arnauld (G II, 96–97, Ariew & Garber, p. 85, 1687). Cited by Rescher, op. cit., p. 48. My emphasis. 24 That is, IF there were material substance, then the reality of that substance could only be the reality of its material constituents. But, since material substance would necessarily be infinitely divisible, there would be no real material constituents, and, hence, material substance is impossible.

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answers the question as to whether his ‘composites’ are phenomenal objects or the complete inner worlds of his ‘dominant Monads.’

10.4 We Have Met the Composites, and They are Us I have argued that there is a choice to be made in the interpretation of Monadology Sect. 2. The first option is that of taking Leibniz to be arguing from the fact that I have a unified laptop representation (meaning #1 of ‘composite’) to there existing an infinite number of independently existing simple substances whose inner lives are correlated with my laptop representation. I think of this as the ‘inference to object simples’ option. The second option is to take Leibniz as arguing from the fact of my having an internally unified consciousness (meaning #2 of ‘composite’) to my necessarily being a simple substance. I think of this as the ‘inference to a simple subject’ option. I believe that it is this second option that best represents Leibniz’s real intent. If it is his intent, then Monadology Sect. 2 is nothing other than a condensed Achilles. The second reading of ‘composites’, then, is the one in which the ‘composites’ are us. This reading is consistent with Leibniz’s account of simple substance, the ‘Monad’, that it is by necessity a ‘multiplicity within a unity.’ It also seems to be exactly what he says to Arnauld about the nature of ‘expression’ (representation): Expression is common to all the forms and is a genus of which natural perception, animal feeling, and intellectual knowledge are species. In natural perception and feeling it suffices that what is divisible and material and is found dispersed among several beings should be expressed or represented in a single indivisible being or in a substance which is endowed with a true unity. The possibility of such a representation of several things in one cannot be doubted, since our soul provides us with an example of it. But in the reasonable soul this representation is accompanied by consciousness, and it is then that it is called thought.25

For Leibniz, all living things are unified as phenomena.26 This means that all aggregates whose perceptual lives share in the narrative of a single living thing are unified in the representation of a special Monad that is included in that aggregate. The best example each of us has of this is, as he says above, ourselves. Each of us is the dominant Monad that expresses the independently existing aggregate of Monads that is our body. Leibniz believes that despite the undeniable successes of materialistic mechanism, it is a failure as a metaphysical doctrine. Quite apart from the frustrating issues of divisibility and of efficient causation, the ‘man-machine’ Cartesian model of the human animal cannot explain our conscious experience and he famously asks where in a machine perceptions are to be found.27

25

Leibniz, Letter to Arnauld (8/9/1867) LL, op. cit., v. II, p. 521. It is unclear whether Leibniz actually held that only living things are unified by a dominant Monad, but since his Sect. 2 argument does not hinge on whether he allotted a dominant monad to inanimates, I will not pursue the question here. 27 Leibniz, Monadology, Sect. 17. See also Woolhouse and Francks, p. 129. 26

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Like Descartes, he is very much aware that the soul is not in the body as a sailor is in his ship, but unlike Descartes, for whom this is a problem,28 he takes the specific manner in which this occurs as the central pivot of his entire philosophy. The ‘dominant’ Monad of a living body expresses in its single unified apperceptive consciousness what is going on in all of its constituent non-apperceptive members perceptual streams.29 Thus, Leibniz gives a functional explanation of the relation of mind and body that is absent in Descartes. On the Leibnizian view, there exists a Monad for every possible point of within our body, though these Monads are non-apperceptive. In order for those Monads to become more than a mere heap or collection, their perceptual streams must be included within a single representation. Such a single representation exists for every living body, though not all such living bodies receive the unification granted by apperception, a unity reserved to human souls or better. What Leibniz is struggling to express with his various metaphors of allegiance and kinship, as Rescher puts it below, is the special and inexpressible experience of the lived body, the way in which our many body experiences are made one in the mind. Leibniz holds that only a unit can unify—only what has unity can engender unity. The unity of any large-scale unit that underlies a plurality of substances must therefore itself be encapsulated in a single substance that serves as the unifier of that whole by suitably representing all of its parts through linkages of qualitative kinship—somewhat as a monarch unifies his people by a system of allegiances. It is because he regards such representative unification as the only possible road to unity that Leibniz stands committed to the view that if there were no simple substances to do this unifying, then there would be no way to unify pluralities into composite wholes. The idea of this Sect. is accordingly not just the trivial point that composites require units because composites are pluralities, but rather the more interesting idea that composites which are themselves unified require true units to serve as unifiers.30

Rescher’s excellent gloss is marred only by a lack of clarity in the use of the word ‘composite’; strictly speaking, Leibnizian ‘pluralities’ are never per se unified, 28

Descartes, Meditations on First Philosophy, Meditation VI. One important implication of this is that Leibniz’s argument (as well as all Achilles arguments) necessarily argues from the existence of my own apperception or reflective self-awareness. The Leibnizian Christian Wolff followed Leibniz in this as well as in many other respects. Richard J. Blackwell (‘Christian Wolff’s Doctrine Of The Soul,’ Journal of the History of Ideas 22. 3 [1961] pp. 339–354) represents Wolff’s own Achilles as follows: 29

The stage is now set for the analysis of the soul itself. The first point is to show that the soul is not material. . . . Wolff indicates that one might argue that perception could occur in matter by means of the various parts of matter producing and sustaining the proper motions. However, there is no way in which apperception could occur in a material body. Hence the consequence is that since the soul does exercise cognition, it must be immaterial. It might be noted in passing that this argument clearly indicates that perception, as distinct from apperception, is a mechanical, pre-conscious act. From the immateriality of the soul Wolff then concludes that it lacks parts, extension, shape, etc. In short, the soul is an immaterial simple substance. (346) 30

Rescher, op. cit., p. 51.

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unless one adopts the post 1709 view, in which case it is still unclear what the role of the dominant Monad’s representation is in the unification of its aggregate. When Leibniz says ‘there are composites,’ what he is referring to is our experience of being unified human beings, bodies unified by consciousness: we have found the composites, and they are us. A Leibnizian ‘composite’ is a perceptual expression within a single Monad of perceptual correlations across many Monads. It is the lived body. My body is an organized mass that includes a number of perceptual organs that combine in a single point of view, and what is perceived from that point of view expresses or represents that organized mass: . . . the organized mass in which the point of view of the soul is found is itself expressed more immediately by the soul . . . 31

But what is the lived body if not the simultaneous and unified having of all of our normal sensations? Leibniz is quite clear that what happens in perception is precisely that, a distributed content is unified into a single representation: ‘our soul provides us with an example of it.’ When Descartes had explored his own ‘I’, he concluded I am a thing that thinks, that is to say, that doubts, affirms, denies, that knows a few things, that is ignorant of many [that loves, that hates], that wills, that desires, that also imagines and perceives; for as I remarked before, although the things which I perceive and imagine are perhaps nothing at all apart from me and in themselves, I am nevertheless assured that these modes of thought that I call perceptions and imaginations, inasmuch only as they are modes of thought, certainly reside [and are met with] in me.32

This is the ‘I’ of which Leibniz is speaking, the ‘I’ that at once hears, sees, tastes, smells, and has kinesthetic awareness, the ‘I’ that is the unified expression of the body. But it is equally true of the ‘I’ within me that it sees the whole of its extended visual field at once, and that it recognizes and discriminates objects within that field, recognizes them to be other composites. The datum of his own unified experience forces him to infer the existence of a simple substance within himself: But in addition to the general principles which establish the monads of which compound things are merely the results, internal experience refutes the Epicurean doctrine. This experience is the consciousness within us of this Ego which perceives the things occurring in the body. And since this perception cannot be explained by figures and movements, it establishes the other half of my hypothesis and makes us recognize an indivisible substance in ourselves which must itself be the source of its phenomena.33

What then of the Achilles?

31

NS, LL, op. cit., v. II, p. 747. Descartes, Meditation III. 33 Leibniz, ‘Reply to Bayle’ (1702) [G IV, 558–59, LL 577], cited by Rescher, p. 85. 32

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10.5 Conclusion: Achilles Found I set the following conditions at the outset for an argument being an Achilles: 1. 2. 3. 4.

It must hypostasize, It must be premised on the existence of the unity of consciousness, It must conclude that an indivisible immaterial substance exists, and It must reason that the existence of the unity of consciousness requires an indivisible immaterial substance as a subject of experience.

The Leibniz argument after elaboration reads like this: A ‘being by aggregation’ must get its being from somewhere. It could get its being from either a divisible or indivisible substance. If it was from a divisible, then its being would come from the divisible’s parts. But since the parts of a divisible are infinitely divisible, no being would ever be found, and the being by aggregation would not exist. It does exist, and therefore, it does not get its being from a divisible substance. Matter is a divisible substance, therefore it does not get its being from matter. Therefore, it must get its being from an indivisible entity. More formally: 1. There are ‘composites’ or ‘beings by aggregation’ or ‘phenomena’ (they have reality). 2. Reality must come from a substance. 3. Substances must either have parts or not have parts. 4. Matter is substance that has parts and mind is substance without parts. 5. Whatever has parts, gets its reality from its parts. 6. Matter cannot have reality. 7. The reality of composites must come from mind. 8. Therefore, mind substance exists. Since the conclusion is to the existence of an inferred kind of entity, condition (1) is satisfied: the argument does hypostasize. Since ‘composites’ are unified personal perceptual ‘worlds’, condition (2) is satisfied. The conclusion is that a specifically immaterial simple substance exists, and so condition (3) is satisfied. And, finally, the inference to the existence of the immaterial substance is defended by appeal to the unity of consciousness in the form of the existence of ‘composites’. Condition (4) is also satisfied. From this, I conclude that Sect. 2 of the Monadology does indeed conceal an Achilles argument. So how should we now read Sect. 2 in the Achilles context? I think that it should be as follows: 2. And there must be simple substances, since each of us expresses our aggregate body in a unified composite experience (and only a simple can contribute unity to an aggregate); for an aggregate by itself (in the absence of a unifying soul) is nothing but an heap of segregated simples.

Chapter 11

Hume’s Reply to the Achilles Argument Lorne Falkenstein

Book 1, part 4, Section 5 of David Hume’s Treatise of human nature attacks the belief in an immaterial soul.1 (It also attacks the belief in a material soul, though that further project is not advertised in the title Hume chose to give to the section, and appears to have been largely incidental to his main purpose.) In the process, it considers and challenges what Hume described as a ‘remarkable’ argument for the immateriality of the soul. This ‘remarkable’ argument has some affinity with an argument that was given by predecessors, such as Ralph Cudworth, Pierre Bayle, and Samuel Clarke; contemporaries such as Etienne de Condillac; and later contemporaries, such as Moses Mendelssohn. It was subsequently described by Immanuel Kant as the ‘Achilles’ of all the purely a priori arguments concerning the soul, an epithet Kant applied because, like the legendary Greek warrior, the argument appears to withstand all opposition.2 (I borrow that name for the argument here.)

L. Falkenstein Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 85774, Fax: (519) 661-3922 e-mail: [email protected] 1 David Hume, A treatise of human nature (London: J. Noon, 1739–40). References to this work are to book, part, section, and paragraph numbers of the edition by David Fate Norton and Mary J. Norton (Oxford: Oxford University Press, 2000). The Introduction, Appendix, and Hume’s subsequently published Abstract, included in this edition, are so referenced and cited by paragraph numbers. 2 Ralph Cudworth, The true intellectual system of the universe (London: Richard Royston, 1678; reprinted in facsimile Stuttgart: Vrommann 1964), 822–834. Pierre Bayle, Dictionnaire Historique et Critique, art. Leucippus, note E (1st edition, 1697; but the relevant passages only first appear in the 2nd edition, 1701). See the 4th edition, 1740, as abridged and translated in Pierre Bayle, Historical and Critical Dictionary, Richard H. Popkin, trans. (Indianapolis: Hackett, 1991), 130–134. Samuel Clarke, A letter to Mr. Dodwell concerning the immortality of the soul; together with the four defenses of it, (originally published as five separate works between 1706 and 1708; reprinted in The Works of Samuel Clarke, D.D. vol. 3 (London: John and Paul Knapton, 1738) which is in turn reprinted in facsimile in Samuel Clarke, Works (New York: Garland, 1978), 721–909. Etienne Bonnot, Abbé de Condillac, Essai sur l’origine des connoissances humaines, I.i.1 §6 (originally published in 1746). Moses Mendelssohn, Phaedon, oder über die Unsterblichkeit der Seele in drey Gesprächen, 2nd dialogue, (Berlin: F. Nicolai, 1767); see the version reprinted in Moses

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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The question of the immateriality of the soul was one of the most hotly disputed questions of the early modern period.3 Appeals to the Achilles argument often figured in that debate.4 But Hume’s particular take on the debate and on this argument in Treatise 1.4.5 have not received much attention.5 One reason for the neglect of Treatise 1.4.5 might be that even the most sympathetic Hume scholars have found what he had to say in that section so puzzling or so patently unacceptable that they have been unwilling to acknowledge that he really meant it. This attitude finds its clearest expression in John Yolton’s claim that 1.4.5 is a ‘satire’ of Malebranche’s immaterialism.6 If 1.4.5 is a satire, then Hume cannot be assumed to be speaking in his own voice when he makes most of the pronouncements to be found in it, and in that case there is little that 1.4.5 can teach us about his own views. I challenge that opinion here. I show that Hume is serious throughout 1.4.5, and that, with the exception of passages explicitly flagged as representations of the views of others, there is very little he has to say in that section that he did not endorse. To do this, I survey versions of the Achilles argument given by Ralph Cudworth, Pierre Mendelssohn, Gesammelte Schriften, Jubiläumsausgabe der Akademie für die Wissenschaft des Judentums, vol. III,1, F. Bamberger and L. Strauss, eds. (Berlin: 1932, [facsimile edition: Stuttgart: Frommann, 1972]), 81–101. Immanuel Kant, Kritik der reinen Vernunft, 1st edition (Riga: Johann Freidrich Hartknoch, 1781), 351. 3 For the classic study of this topic, see John Yolton, Thinking Matter. Materialism in Eighteenth Century Britain (Minneapolis: University of Minnesota Press, 1983). 4 See Ben Lazare Mijuskovic, The Achilles of rationalist arguments : the simplicity, unity, and identity of thought and soul from the Cambridge Platonists to Kant (The Hague : Martinus Nijhoff, 1974). 5 The notable exception, an early one, is Thomas Reid, whose philosophical career was radically altered by this particular text. Reid declared that he had been a Berkeleian until he discovered that the same arguments that Berkeley had used to reject the existence of matter could be employed to reject the existence of spirits (in Thomas Reid, Essays on the intellectual powers of man (Edinburgh: John Bell, 1785); critical edition edited by Derek Brookes (Edinburgh: Edinburgh University Press, 2002), 142. This declaration was a remark on what Reid had learned from reading Treatise 1.4.5, which therefore has some claim to have been the (negative) inspiration for Reid’s attempt to forge an alternative to the theory of ideas. The most explicit indication of the dominant influence this part of the Treatise played on Reid’s thought can be gleaned from Thomas Reid, An inquiry into the human mind on the principles of common sense (Edinburgh: A. Millar, 1764); critical edition edited by Derek Brookes (University Park, PA: The Pennsylvania State University Press, 1997), 217. Exceptions to the recent neglect of 1.4.5 are Mijuskovic, 86–88 and 107–108; Yolton, Thinking Matter, 49–63; Jane L. McIntyre, ‘Hume: second Newton of the moral sciences,’ Hume Studies 20 (1994): 3–18; Lorne Falkenstein, ‘Hume and Reid on the simplicity of the soul,’ Hume studies 21 (1995): 25–45; and Paul Russell, ‘Hume’s Treatise and the Clarke-Collins controversy,’ Hume studies 21 (1995): 95–115. 6 Yolton, Thinking Matter, 53, 56. In contrast, McIntyre (1994) suggests that while the tone of Treatise 1.4.5 is ‘satirical throughout,’ the section is not ‘merely a vehicle for presenting Hume’s critical (and lampooning) remarks about the debate between the materialists and the immaterialists.’ Instead, his arguments ‘are actually quite focused’ (5). However, she takes his arguments to be focused on a refutation of Clarke, and, at a crucial point, is willing to rest Hume’s case on a merely ad hominem use of Clarke’s own principles against him. I argue below that Clarke was not Hume’s primary opponent (Cudworth and Bayle are more likely targets) and that Hume’s case is based on his own principles.

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Bayle, and Samuel Clarke—predecessors whom Hume is most likely to have had in mind when he wrote what did in Treatise 1.4.5. My aim is to demonstrate that there is a standard take on the argument that Hume could hardly have missed. I then argue that Hume’s own treatment of the argument departs from this standard in a number of important ways. I argue that the departures are all ones that Hume would have considered to be improvements. They restate the argument in Humean terms, replacing premises concerning inherence, substance, and action, which Hume considered to be false or unintelligible, with ones mentioning conjunction at a location in space, which he considered to be at least intelligible. On the basis of these considerations I conclude that Hume did not intend to satirize or lampoon the views of any of his predecessors. A satire or lampoon exposes a flat statement of its target view to ridicule. It does not modify that view—certainly not by way of introducing improvements to make it more intelligible. For better or for worse, 1.4.5 has something to teach us about Hume views on mind and representation. In subsequent sections I respond specifically to Yolton’s charge that Treatise 1.4.5 is a satire on the views of Malebranche and I consider just how effective Hume’s attempt to respond to the Achilles is. I begin by taking a position on what Hume is up to in Treatise 1.4.5.

11.1 The Project of Treatise 1.4.5 Hume opened Treatise 1.4.5 with the comment that though there are gaps in our knowledge of the ‘intellectual’ (or perhaps better internal) world, there are no contradictions of the sort he had discovered when investigating the basis of our belief in the ‘natural’ (or perhaps better external) world. ‘What is known concerning it, agrees with itself;’ he wrote, ‘and what is unknown, we must be contented to leave so.’ One question about Treatise 1.4.5 concerns how to reconcile this claim with a skeptical position taken on knowledge of the material or immaterial nature of the soul at the close of the section, in 1.4.5.33. Hume was capable of reversing himself. The confident hopes for success from prosecuting a science of the mind that he expressed in the introduction to the Treatise (Introduction 6) appear to be abandoned in Treatise 1.4.7. The claim of Treatise 1.4.2.1 that the existence of body must be taken for granted is disavowed in 1.4.2.56. Even the claim just mentioned, that the internal world is not involved in contradictions, is rejected in Hume’s appendix to the Treatise (Appendix, 10). But Hume does not seem to have reversed himself over the course of Treatise 1.4.5 itself, between its opening at 1.4.5.1 and its pronouncement of a final decision at 1.4.5.33.7 Having said in 1.4.5.1 that there are only gaps in our knowledge of the internal world, not contradictions, Hume went on in 1.4.5.2 to remark that such contradictions as might

7

When Hume did question the claim that there are no contradictions in our knowledge of the internal world in the Appendix, it was on the basis of results uncovered in the following 1.4.6, not 1.4.5.

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be imagined to plague the subject only arise when ‘curious reasoners’ attempt to fill gaps that cannot be filled. ’Tis true, wou’d we hearken to certain philosophers, they promise to diminish our ignorance; but I am afraid ’tis at the hazard of running us into contradictions, from which the subject is of itself exempted. These philosophers are the curious reasoners concerning the material or immaterial substances, in which they suppose our perceptions to inhere. (Treatise 1.4.5.2)

The whole project of Treatise 1.4.5 was to show that this particular gap in our knowledge cannot be filled. In 1.4.5.1 Hume declared himself to be satisfied with the coherence of the account of the internal world of impressions, ideas and their interactions under principles of association articulated in the earlier sections of the Treatise. In 1.4.5.2 he said that it is only when we attempt to go beyond this introspectively evident science of the mind, and attempt to fill in some of the remaining gaps (notably that concerning the nature of a ‘substance’ in which our perceptions are supposed to ‘inhere’), that we run into difficulties. In 1.4.5.33 he concluded that he had succeeded at showing this to be the case. Treatise 1.4.5 is thus an exposition of difficulties that arise when we attempt to go beyond the proper boundaries of a consistent science of the mind, not an exposition of any hidden inconsistencies within the proper limits of that science.

11.2 Hume’s Sufficient Reasons for Abandoning the Dispute Let’s look more closely at Hume’s reasons for thinking we cannot determine whether the soul is material or immaterial. As early as 1.4.5.6, Hume claimed to have arrived at a ‘sufficient reason for abandoning utterly that dispute concerning the materiality and immateriality of the soul.’ This reason is that ‘substance’ and ‘inherence’ are meaningless words. Hume charged that because the very terms are meaningless, we should not even go so far as to consider our ignorance of the nature of mental substance to constitute a gap in our account of the internal world. Instead, we ought to ‘absolutely condemn even the question itself.’ There simply is no gap to be filled. Hume offered two arguments to justify this charge of meaninglessness: 1. He charged that since all ideas are derived from antecedent impressions, we could only have the idea of a substance if we had an impression of such a thing. But not only has no one managed to isolate and classify any such impression, it seems impossible to do so. For how can an impression represent a substance, otherwise than by resembling it? And how can an impression resemble a substance, since, according to this philosophy, it is not a substance, and has none of the peculiar qualities or characteristics of a substance? (Treatise 1.4.5.3)

This argument is as interesting for what it premises as for what it concludes. Hume premised that for there to be an impression ‘of’ something is for there to be an impression that resembles that thing. So, for there to be an impression of a pain is

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for there to be a painful impression; for there to be an impression of a red square is for there to be a red, square impression; for there to be an impression of a hard, cold ball is for there to be a hard, cold, globular impression; and so on. This premise, moreover, is not attributed to ‘this philosophy’ (the philosophy of the ‘curious reasoners concerning the material or immaterial substances, in which they suppose our perceptions to inhere’). The only tenet that Hume attributed to that philosophy is the tenet that impressions are not substances (presumably, they are either ‘modifications’ or ‘acts’ of substances, following the suggestion of Treatise 1.4.5.26–28). Given that starting point, Hume asked the ‘curious reasoners’ what impression our idea of substance is copied from. The suggestion that the only way to arrive at an idea of something is via an impression that resembles (or, perhaps better, simply is) that thing is Hume’s own, used by Hume to argue that the ‘curious reasoners’ cannot in principle account for the origin of the idea of something in which impressions are supposed to inhere. 2. Setting aside the question of what impression might give us an idea of substance, Hume went on to give a second argument. He observed that if we proceed from the standard definition of ‘substance’ as ‘that which can exist on its own,’ then each of our impressions has a title to be considered a substance. Each is different and distinguishable and separable from everything else that we can perceive and so does not need to ‘inhere’ in anything else in order to exist. Impressions are therefore neither modifications nor acts of anything else. They are each ‘beings’ or objects in their own right. The same holds of ideas, since they are copies of impressions. These two arguments draw on some of the most characteristic tenets of Hume’s account of the internal world: the first on the tenet that ‘every idea is deriv’d from a precedent impression’ (cf. Treatise 1.1.1.7); the second on the tenets that ‘every thing, which is different, is distinguishable, and every thing which is distinguishable, is separable by the imagination’ (cf. Treatise 1.1.7.3), and that ‘whatever is clearly conceiv’d may exist; and whatever is clearly conceiv’d after, any manner may exist after the same manner’ (Treatise 1.2.6.4). The further tenet, used as a premise of the first argument, that for there to be an impression of an object is for there to be an impression that resembles that object is not attributed to anyone else. Its presentation by way of a rhetorical question or a challenge suggests that Hume considered it to be the only available account of representation. We may wonder whether Hume was right to maintain that for an impression to represent an object is for it to resemble that object. After all, the word ‘cat’ represents cats without resembling cats; smoke represents fire without resembling fire, and in general signs represent their signata and causes or effects represent their effects or causes even in the absence of any significant degree of resemblance. And, as has often been pointed out by recent philosophers, everything resembles everything else in some way or other, but not everything represents everything. These objections notwithstanding, the view I have drawn from Hume’s text is not implausible. It is certainly not so implausible that Hume could not have entertained it. Note that Hume’s claim concerns how an impression can represent an object, not

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how an impression can cause an idea that represents an object. As is well known, Hume had a story to tell about how, in virtue of association on the basis of past experience, an impression might cause (not represent) an idea—an idea, moreover, that bears no resemblance to the original impression. The cases mentioned earlier are all cases of this sort. Word-impressions cause ideas that represent objects, cause-impressions cause ideas that represent effects, effect-impressions cause ideas that represent causes. In general, impressions that represent signs cause ideas that represent signata in virtue of repeated prior experience of the conjunction of sign and signatum, producing a habit to associate the two. In virtue of these antecedents, an impression that represents the sign causes an idea that represents the signatum, and so, in a mediate sense, the sign represents the signatum. But without those antecedents, the sign represents nothing other than itself. Smoke represents nothing other than itself to Adam on the first day; and ‘cat’ represents nothing other than a noise to someone with no knowledge of English. Similarly, apart from association, an impression represents nothing other than itself. The only object it can represent is an object that resembles the impression so closely that only a verbal distinction can be drawn between the two.

11.3 The ‘Remarkable Argument’ Whatever we may think about the soundness of Hume’s arguments over Treatise 1.4.5.3–6, they are presented as a satisfactory refutation of any attempt to maintain that perceptions need to ‘inhere’ in any sort of mental substance. But Hume’s treatment of this question did not end with them. At Treatise 1.4.5.7, after having apparently concluded his case, he stopped in his tracks and declared that ‘There is one argument commonly employ’d for the immateriality of the soul, which seems to me remarkable.’ Paragraphs 8–16 of Treatise 1.4.5 are devoted to stating and answering this ‘remarkable’ argument, the following paragraphs 17–25 are devoted to buttressing that answer by charging that immaterialism is a kind of Spinozism, and a further three paragraphs, 26–28, are devoted to attacking the claim that the argument might be defended by considering perceptions to be ‘acts’ performed by the mind rather than ‘modifications’ inhering in it. Hume clearly took the argument very seriously—so seriously that he considered it to pose a challenge to an already ‘sufficient reason’ for rejecting the view that perceptions inhere in a mental substance. As noted earlier, Hume’s ‘remarkable’ argument bears some resemblance to an argument found in Cudworth, Bayle, and Clarke (to mention but a few), and dubbed the ‘Achilles’ argument by Kant on account of its apparent invincibility. Hume would almost certainly have read Bayle’s and Clarke’s versions of the argument, and might well have come across Cudworth’s or the primary texts by Plotinus that Cudworth principally devoted himself to presenting. But Hume’s version of the argument is also subtly different from what he would have found in any of those sources.

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As detailed elsewhere in this volume, the Achilles argument proceeds over two stages: 1. At an initial stage, body or matter is defined to be something that consists of parts, each of which can exist apart from the others. It is then argued that the power of thought or representation or consciousness could not be a quality that emerges from the way these parts are arranged to form a compound. This is the case because the only qualities that are truly emergent, in the sense of being something other than what is already found dispersed in lesser degrees over the parts (as the mass or momentum of a whole is simply the product of the masses or momenta of its parts), are qualities that are really only to be found in the mind of a thinking being who perceives the whole. Emergent qualities, like beauty and harmony, are not really qualities inhering in compounds themselves but are rather feelings arising in the minds of those who contemplate these compounds, and the same holds of all other emergent qualities. For this reason, emergent qualities are one and all ‘secondary qualities.’ But then the power of thought or consciousness itself could not be taken to be an emergent quality without generating a vicious regress.8 2. It follows that if matter thinks or is conscious, then thought or consciousness must inhere in one or more of its parts, rather than emerge from how unthinking or unconscious parts are arranged. A second stage of the argument comes into play at this point. (2a) It is charged that thought or consciousness could not be distributed over many parts. A thought, such as the thought of a horse or a tree or a triangle or a globe, is a whole rather than a simple. It consists of many parts (the thoughts of the horse’s head an legs, of the individual branches and leaves of a tree, of the vertices of the triangle, of the different continents painted on the globe, etc.) arranged in a special way to make a characteristic form. Were these 8 See, for instance, Clarke, A defence of an argument made use of in a letter to Mr. Dodwell, in Works 3:759–760, where the ‘powers’ that can be attributed to a thing are divided into three sorts. First there are powers that really reside in that thing. Second, there are powers that only appear to a conscious being to reside in a thing because of the way the conscious being is affected (as objects appear to us to have a power to manifest colors, though all that they actually have is a texture of shaped and moving parts). Finally, there are powers that only appear to a conscious being to reside in a thing because of the way it interacts with other things (as objects are said to gravitate towards or electrically attract or repel one another, though all that actually happens is that their subsequent aggregate motions can be deduced from the antecedent circumstances in accord with laws). Clarke went on to claim that a power of thought or consciousness could not be a power of either of the second two types. The power of thought could not be a power that only appears to something that has the power of thought—that produces a circle or an infinite regress. Clarke’s point had earlier been made by Cudworth: ‘It is true indeed, that Corporeal Qualities and Forms, according to the Atomic Physiology, result from a Composition and Contexture of Atoms or Parts, each of which taken alone by themselves, have nothing of that Quality or Form in them, . . .; but the Reason of the difference here is plain, because these Qualities and Forms are not Entities Really distinct from the Magnitude, Figure, Site, and Motion of Parts, but only such a Composition of them, as cause different Phancies in us; but Life and Understanding, Soul and Mind, are Entities Really distinct from Magnitude, Figure, Site, and Motion of Parts, they are neither meer Phancies, nor Syllables of things, but Simple and Uncompounded Realities.’ (823–824)

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parts of the thought distributed to different parts of a material, thinking thing, so that one part had the thought of, say, a horse’s head, another of its left front leg, then there would be no one part that is aware of the whole horse. Alternatively, were each part supposed to be conscious of the whole, then any thinking body would contain multiple thinking things. Neither alternative squares with our experience. I am aware of whole objects and of relations between individual objects, binding them into yet larger wholes (ultimately, a world). And I have no evidence that I share my body with other thinking beings. (2b) But supposing that thought or consciousness inheres in just one part is not tenable either. For, if matter is infinitely divisible, any one part, however small consists of infinitely many further parts over which thought would have to be somehow distributed. If, alternatively, matter is composed of simple, indivisible parts, and just one of these parts has the power of thought, then it is not the material composite that thinks, but something that does not consist of parts and is indivisible. We are therefore compelled to accept that what thinks in us is incomposite and hence immaterial.9 Not all versions of the Achilles argument devote equal attention to these two stages. Clarke focused on the first, Bayle on the second. But Cudworth gave equal attention to both and Hume would have been able to gather the entire argument from various sources. His own presentation of the ‘remarkable’ argument draws most on the second stage and reads as follows: Whatever is extended consists of parts; and whatever consists of parts is divisible, if not in reality, at least in the imagination. But ’tis impossible any thing divisible can be conjoin’d to a thought or perception, which is a being altogether inseparable and indivisible. . . .If it be conjoin’d with the extension, it must exist somewhere within its dimensions. If it exist within its dimensions, it must either exist in one particular part; and then that particular part is indivisible, and the perception is conjoin’d only with it, not with the extension: Or, if the thought exists in every part, it must also be extended, and separable, and divisible, as well as the body; which is utterly absurd and contradictory. For can any one conceive a passion of a yard in length, a foot in breadth, and an inch in thickness? Thought, therefore, and extension are qualities wholly incompatible, and never can incorporate together into one subject. (Treatise 1.4.5.7)

There are obvious affinities between this ‘remarkable’ argument and the Achilles. Both arguments seek to establish that thought cannot be attributed to anything that

9

Bayle’s statement of this argument (Dictionnaire, 130) is particularly compelling: ‘Consider the shape of the four parts of the world on a globe. . . .[I]f this globe were capable of knowing the shapes with which it has been decorated, it would contain nothing that could say, “I know all Europe, all France, the whole city of Amsterdam, the whole Vistula”; each part of the globe could only know the portion of the shape that fell to it; and since that part would be so small as not to represent any place entirely, the globe’s capability of knowing would be absolutely useless.’ But see also Cudworth, 824–825 ‘If the Soul be a Magnitude, then must it be divided together with the Sensible Object, so that one Part of the Soul must perceive one Part of the Object, and another, another; and nothing in It, the Whole Sensible: just as if I should have the sense of one thing, and you of another. Whereas it is plain by our Internal Sense, That it is One and the Self same thing in us, which perceives, both the Parts and the Whole.’

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is composite. And both seek to do so by arguing that a thought could neither exist in just one part nor in multiple parts. But there are also differences. One of them was underscored by Hume himself in the immediately following sentence. ‘This argument,’ he wrote, ‘affects not the question concerning the substance of the soul, but only that concerning its local conjunction with matter’ (Treatise 1.4.5.8). In fact, a cursory look at the text of Treatise 1.4.5.7 shows that it does not even affect the question concerning the local conjunction of the soul with matter. It rather affects the question concerning the local conjunction of thought with matter, that is, the question of which parts of our bodies might be the ones in which impressions and ideas are placed. Cudworth, Bayle, and Clarke had framed the question in different terms. Their concern was with whether a power of thought or consciousness could inhere in a material substance. But over Treatise 1.4.5.3–6, Hume had already given what he described as ‘a sufficient reason for abandoning utterly that dispute’ concerning the inherence of thought in a material substance—indeed, a sufficient reason to ‘absolutely condemn even the question itself’ (Treatise 1.4.5.6). Hume found the Achilles argument ‘remarkable’ because he saw something in its second stage that posed the old question of the material or immaterial nature of the soul in new and more intelligible terms—in terms of location at a place rather than inherence in a substance. This was the question raised in a particularly evocative form by Bayle when he charged that a globe could not have the thought of the map of the earth because each of its parts is painted with only one small part of that map and none receives the image of the whole, and that an extended soul could not have the impression of an entire horse or an entire tree because only a part of the impression would be contained in any one part of the soul. One need not make any reference to inherence in a substance to find this charge compelling, and to take it to suggest that bodies could not think because thoughts could not be distributed over locations in bodies. Treatise 1.4.5.7 contains other divergences from the Achilles argument that follow from this shift of focus. Rather than argue that thought could not be found in matter or body considered as a thing that is divisible into parts, Hume argued that thought could not be found in anything that is extended. Not everyone agreed. Clarke had maintained that there are some extended things that are not divisible into parts, and had been concerned to argue that thought could not inhere in what is divisible into parts, while holding out the possibility that it might inhere in an extended but ‘indiscerpible’ substance.10 Henry More shared these views, and 10 2nd defence, 794–795. Compare Collins’s postscript reply to Milles in his A reply to Mr. Clarke’s defence, reprinted in Clarke, Works 3: 778–779. The following passage is noteworthy in light of Hume’s own reply to the ‘remarkable’ argument: ‘For if an Immaterial Being or Soul be, according to Mr. Clarke, an extended Being, and yet indiscerpible both by the Powers of Nature and the Power of God, then Mr. Milles Assertions, That if that which thinks in us be extended, it must consist of Parts, and that it is impossible that what has Parts should be the Subject of Thought, do overthrow Mr. Clarke’s Demonstration of the Immateriality of the Soul; for if whatever is extended must consist of Parts, and if that which consists of Parts cannot think, then Mr. Clarke’s Immaterial Being cannot think, and consequently the Immateriality of the Soul, in Mr. Clarke’s Sense, is destroyed by Mr. Milles’s Defence[.]’

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Cudworth at least allowed for them.11 Hume dismissed this possibility and his concern with local conjunction explains why. Clarke could fancy that a thought that inheres in an extended but indivisible substance could inhere in that substance without being distributed or multiplied over various parts. But Hume observed that whatever is extended consists of parts set outside of parts and so is divisible ‘at least in the imagination.’ The question of which parts of an extended soul a thought might be conjoined with—of whether the whole thought is conjoined with each part or a part of the thought distributed to each—cannot therefore be avoided. Perhaps the most striking way in which Treatise 1.4.5.7 diverges from common statements of the Achilles argument is in terms of the reasons it gives for rejecting the alternatives. While it gives the standard reason for rejecting the possibility that thought might be conjoined with just one part of an extended soul (that this alternative gives up the ghost by admitting that the thing that thinks is incomposite and so neither corporeal nor extended), it does not give the standard reason for rejecting the possibility that thought might be conjoined with more than one part (that then there would either be multiple occurrences of the thought in the different parts or no one part that has the whole thought). Instead, it charges that since thoughts do not have length, breadth, or thickness, they could not be locally conjoined with more than one part of an extended thing.12 Here, too, a reformulation of the argument in terms of local conjunction is behind the change. Standard versions of the Achilles suppose, for purposes of reductio ad absurdum, that thoughts might be locally conjoined with extension and then appeal to the fact that we are conscious of wholes or that our bodies are not governed by multiple personalities to demonstrate the absurdity of that supposition. But this involves appeal to a special relation (call it ‘consciousness’ or ‘inherence’) obtaining between a (substantial) mind or self and its (proprietary) thought. Hume’s alternative statement of the argument avoids that further appeal, by taking the supposed inseparability and indivisibility of the thought to rule out the possibility of any sort of conjunction with extension. These divergences suggest that Hume did not intend to write a satire of the views of his predecessors. A satire begins by getting the views of those being satirized more or less right and then holding them up to ridicule. Rather than get the Achilles 11 Cudworth, 832–834. For More see the discussion in Reid, ‘Henry More on Material and Spiritual Extension.’ 12 This claim is not entirely unprecedented. One of the variants on the Achilles presented by Cudworth turned on the claim that everything that the soul knows is ‘Unextended and Devoid of Magnitude,’ so that ‘the Soul Conceives Extended things themselves, Unextendedly and Indivisibly; for as the Distance of a whole Hemisphere is contracted into a narrow Compass in the Pupil of the Eye, so are all Distances yet more contracted in the Soul it self, and there Understood Indistantly; For the Thought of a Mile Distance, or of Ten thousand Miles, or Semidiameters of the Earth, takes up no more Room in the Soul, nor Stretches it any more, than does the Thought of a Foot or Inch, or indeed of a Mathematical Point’ (827). This is so much the case, Cudworth went on to assert, that ‘we can not only Conceive Extension without Cogitation, and again Cogitation without Extension; . . .but also are not able to Conceive Cogitation with Extension’ (828, my italics). Mijuskovic, 86, first drew my attention to this antecedent.

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argument right, Hume modified it. Moreover the modifications are not ones that caricature or distort the argument for purposes of subjecting it to ridicule. Instead, they are informed by Hume’s own prior commitments, and were made to present the argument in the strongest light, given those commitments. Even if the notions of substance and inherence make no sense, and the question of whether a power of thought inheres in a material or an immaterial substance is therefore unintelligible, there is another question posed by a ‘remarkable’ argument for the immateriality of the soul that is not unintelligible and that deserves to be more closely considered. That question rewrites unintelligible talk of the inherence of a power of thought in a composite substance with the rather more intelligible question of where the ‘entire images’ we experience when we are affected by objects might be located.13 Bayle certainly did raise this question when he asked how a globe would be affected by an entire image, and Cudworth at least alluded to it when he worried about how a ‘Parvitude or Atom’ could ‘receive upon it’ the representation of a face, picture, or edifice.14 It was to continue to be echoed in Condillac’s, Mendelssohn’s, and Kant’s considerations of how different representations might be distributed to different parts of a corporeal thing.15 ‘Local conjunction,’ whether in space (as with Bayle’s example of colors on the surface of a globe) or over time (as with Kant’s example of the words of a verse spoken to different subjects), is at issue in the Achilles argument, and should it turn out that thought is the sort of thing that cannot in principle be locally conjoined with anything that is extended, then it would follow that, in the only sense in which Hume was still willing to recognize the notions of inherence or belonging as being intelligible (that of one thing being contained within the dimensions of another or the coincidence of two things at a point), thought could not belong to anything material.

11.4 Hume’s Reply to the Remarkable Argument The ‘remarkable’ argument has a sound basis in Hume’s own account of the workings of the mind. According to Hume, our thoughts are our impressions of sensation, our passions, and the ideas that copy them. Many of these perceptions are as a matter of fact unextended. A passion has no length, breadth, or thickness (Treatise 1.4.5.7). A desire, relish, sound or smell cannot be square, round, or triangular (Treatise

13 This interpretation is supported by a summary statement at the outset of Treatise 1.4.5.29: ‘From these hypotheses concerning the substance and local conjunction of our perceptions, we may pass to another, which is more intelligible than the former and more important than the latter, viz. concerning the cause of our perceptions.’ Hume’s use of the plural, ‘hypotheses’, suggests that the supposition that our perceptions inhere in an immaterial substance is treated as a different ‘hypothesis’ from the supposition that they cannot be locally conjoined with an extended substance. The former is refuted by Treatise 1.4.5.2–6, the latter by 1.4.5.8–28. 14 Cudworth, 825. 15 The absence of this issue from the Clarke/Collins dispute suggests that Treatise 1.4.7 was not directed at anything Clarke, in particular, had to say.

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1.4.5.9). Neither could these sorts of impressions and ideas have even so much as a location in space. For if they had a location then it would be possible, by placing them alongside one another to form figures of a determinate length, breadth and thickness, or to specify what position one of them occupies relative to another and so say, for example, that a moral reflection is placed to the left of a passion. Hume did not consider that we could say such things (Treatise 1.4.5.9–10). It seems impossible, therefore, that these perceptions could be locally conjoined with an extended object. Rather than immediately contest these claims, Hume first went on a digression (Treatise 1.4.5.11–14) to buttress them by explaining why smells, tastes, and sounds are commonly supposed to fill the extension of spatially located bodies even though they are actually nowhere in space. In brief, he argued that our tendency to associate these sensations with particular objects of vision or touch impels the imagination to ‘compleat the union’ by supposing a fictitious coincidence in space to hold of the two sets of sensations. Interestingly, the fiction exhibits the same sort of internal inconsistency that Cudworth and Bayle found in the claim that thought in general might occur in a composite thing. Biting an olive, I only experience one sensation of taste. Looking at the circular green color patch of an olive on a table, I can neither conjoin each pointal, green visual impression with an idea of the taste (because there is just one taste, not many), nor conjoin just one, pointal green impression with an idea of taste (because I think the taste inheres in the whole olive, and hence all the green impressions composing it). Since it is patently absurd to suppose that the sensation exists completely and entirely in each point of the extension without determent to its simplicity, my only recourse is to reject the natural impulse to suppose there is a coincidence and maintain that the taste and color are not and could not even possibly be in any way conjoined in space. There is more implied by these remarks than just that we have good reason to dismiss the view that (some of) our perceptions are extended. Hume’s project in Treatise 1.4.5 was to show that the ‘curious reasoners’ had failed to prove that thoughts inhere in an immaterial soul and, as has been shown above, he had two main sorts of immaterialists to contend with. There were immaterialists like Plotinus and Bayle, who maintained that the soul is unextended or at best pointal or atomic, but there were also immaterialists like More and Clarke and possibly Cudworth, who maintained that the soul is extended but nonetheless incorporeal (because ‘indiscerpible’). Though I argued above that Hume had good reasons to dismiss the views of Moore and Clarke, it bears noting that in insisting that some of our thoughts are nowhere in space and so cannot be conjoined with anything extended, Hume was not just accepting evidence that refutes materialism. He was also exhibiting evidence that refutes any form of immaterialism that takes the soul to be extended but incomposite. An unextended perception could not be conjoined with an extended soul without either being conjoined with the whole soul or being conjoined with some point within the extension of the soul, and neither alternative is acceptable. The former alternative spatializes the sensation by making it exist in multiple places at once; the latter divides the soul into a portion that has the perception and a remainder that does not.

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Hume went on to refute the other form of immaterialism as well. Even though he was willing to accept that some of our perceptions are not located anywhere in space, he denied that this is true of all of them. And he based this denial on his own prior commitments, not on an ad hominem appeal to other things the ‘curious reasoners’ had said. So, where Cudworth had written: Nay, the Soul Conceives Extended things themselves, Unextendedly and Indivisibly; for as the Distance of a whole Hemisphere is contracted into a narrow Compass in the Pupil of the Eye, so are all Distances yet more contracted in the Soul it self, and there Understood Indistantly; For the Thought of a Mile Distance, or of Ten thousand Miles, or Semidiameters of the Earth, takes up no more Room in the Soul, nor Stretches it any more, than does the Thought of a Foot or Inch, or indeed of a Mathematical Point.16

Hume wrote: I first take the least idea I can form of a part of extension, and being certain that there is nothing more minute than this idea, I conclude, that whatever I discover by its means must be a real quality of extension. I then repeat this idea once, twice, thrice, &c. and find the compound idea of extension, arising from its repetition„ always to augment, and become double, triple, quadruple, &c. till at last it swells up to a considerable bulk, greater or smaller, in proportion as I repeat more or less the same idea. (Treatise 1.2.2.2)

Hume here appealed to the same sort of naïve introspection that Bayle appealed to when he claimed to be aware of an entire horse or an entire tree. My impressions of color—the raw phenomenal looks of reds and greens that I feel when I look at a colored object and that all early modern philosophers regarded as mere sensations existing in me rather than as qualities of external objects—are disposed at locations on an extended visual field to form aggregates of different figures and sizes. My ideas copy those impressions and consequently themselves have a size and shape. As a consequence, it makes literal sense to talk of placing one idea on top of another, or locating it somewhere within the boundaries occupied by another. This idea of Rome I place in a certain situation on the idea of an object, which I call the globe. (Treatise 1.3.9.4)

The view that some impressions and ideas are extended is not only justified by introspection. Hume’s own views in Treatise 1.1, dictate that if we have the idea that any objects whatsoever are extended, it is only because we have impressions that represent those objects as being extended. And, Hume’s own views in Treatise 1.4.5.3— before any purported ‘satire’ of the ‘remarkable’ argument is initiated—dictate that those impressions can only represent objects as being extended by resembling or being those extended objects. It follows that at least some of our impressions and ideas must be extended. And Hume said as much. The most vulgar philosophy informs us, that no external object can make itself known to the mind immediately, and without the interposition of an image or perception. That table, which just now appears to me, is only a perception, and all its qualities are qualities of a perception. Now the most obvious of all its qualities is extension. The perception consists of parts. These parts are so situated, as to afford us the notion of distance and contiguity;

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of length, breadth, and thickness. The termination of these three dimensions is what we call figure. This figure is moveable, separable, and divisible. Mobility, and separability are the distinguishing properties of extended objects. And to cut short all disputes, the very idea of extension is copy’d from nothing but an impression, and consequently must perfectly agree to it. To say the idea of extension agrees to any thing, is to say it is extended. (Treatise 1.4.5.15)

These extended impressions and ideas are our compound impressions and ideas of vision and touch—impressions and ideas that Hume was careful to exempt from the list when he claimed that (some of) our impressions and ideas do not exist at any location in space. [N]or is there anything, but what is colour’d or tangible, that has parts dispos’d after such a manner, as to convey [the idea of space and extension]. (Treatise 1.4.5.9, my italics) An object may be said to be no where, when its parts are not so situated with respect to each other, as to form any figure or quantity; nor the whole with respect to other bodies so as to answer to our notions of contiguity or distance. Now this is evidently the case with all our perceptions and objects, except those of the sight and feeling. (Treatise 1.4.5.10, my italics)

In these paragraphs color, tactile feeling, relish, sound, desire, moral reflection, and smell, are all described as ‘objects and perceptions,’ and the only difference that is identified as holding between them is that some exist in space whereas others do not. There is no suggestion that some (colors and solidity) are objects of perceptions whereas others (desires and moral reflections, and perhaps relishes, sounds and smells as well) are just perceptions. In whatever sense a desire or a pain is a perception, a color is a perception; and in whatever sense a desire is a perception that does not exist in space, a pain and a color are perceptions that do exist in space. Having made this point, Hume felt himself in a position to declare that an extended perception can no more be locally conjoined with an unextended subject than an unextended perception can be locally conjoined with an extended one (Treatise 1.4.5.16). The same problems arise either way. In the latter case, we have to worry how one perception could be locally conjoined with every part of the soul without becoming extended; in the former, we have to worry how one soul could be locally conjoined with every part of the perception without becoming extended. Hume’s proposed solution was to reject the notion that our perceptions are locally conjoined with either an extended or an unextended soul, just as he had earlier rejected the notion that our perceptions inhere in either a material or an immaterial subject (Treatise 1.4.5.33). Instead, each perception is an independent existent that neither inheres in, nor is contained in anything else. Hume may have thought that this conclusion does an end-run around the Achilles argument. Where proponents of the Achilles argued that a composite thing could not have a thought because then, untenably, either no part of the composite would have the whole thought or every part would, Hume replied that, indeed, a composite thing could not have a thought. But this is not because there is anything uniquely problematic about the conjunction of thought with something that is divisible into parts. It is rather because thoughts are not modifications of any more fundamental kind of being, extended or unextended, but are independent existents in their own right.

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Seen in this light, Hume’s decision to address the problem of local conjunction by replying to the charge that no thought is extended ends up answering what, in the introduction to this volume is called the ‘narrowest’ Achilles argument (the argument understood as focused on a question about the inherence of thought in a composite substance) as well. It just does so in what Hume would have called an ‘oblique’ fashion.

11.5 The Sincerity of Hume’s Argument in Treatise 1.4.5 John Yolton has described Treatise 1.4.5 as a ‘satire’ on the views of Malebranche rather than a serious representation of Hume’s own views.17 Malebranche is famous as the author of a passage declaring that when the soul perceives the stars, it is not because it travels out into the heavens to be in contact with them, but rather because it perceives something else that is more intimately conjoined with it.18 The declaration is based on the plausible presumption that there can be no action at a distance, which suggests that the objects that cause our perceptions must somehow be in contact with us. Hume’s observation that the ‘remarkable’ argument ‘affects not the question concerning the substance soul, but only that concerning its local conjunction with matter’ (Treatise 1.4.5.8) might lend itself to being read as a direction to think of Malebranche’s position and its implication that there must be some sort of contact between the immediate object of perception and the soul. In that case, Hume’s charge at Treatise 1.4.5.16, that it is as difficult to conjoin an extended thought with an unextended soul as it is to conjoin an extended soul with an unextended thought, could be read as a clever application of one of Malebranche’s own principles, the principle that the soul can only perceive what is in contact with it, to attack Malebranche’s immaterialism—a move that tells us nothing about Hume’s own commitments. In contrast, I have read Hume as arguing that, while the notion of inherence in a substance makes no sense, that of conjunction at a location in space is intelligible, so that a reformulated version of the Achilles argument, stated not in terms of the inherence of a power of representation in a substance, but in terms of the conjunction of a thought with an extended thing, is ‘remarkable’ or noteworthy. It poses a serious challenge to materialism, thus tipping the balance in favor of immaterialism and challenging Hume’s claim that we can make no progress towards answering the question of the substance of the soul.

17

See note 6 above. Nicholas Malebranche, De la recherche de la vérité, book 3, part 2, Chapter 1. Malebranche wrote, ‘I think everyone agrees that we do not perceive objects external to us by themselves. We see the sun, the stars, and an infinity of objects external to us; and it is not likely that the soul should leave the body to stroll about the heavens, as it were, in order to behold all these objects. Thus, it does not see them by themselves, and our mind’s immediate object when it sees the sun, for example, is not the sun, but something that is intimately joined to our soul, and this is what I call an idea.’ Translation by Thomas M. Lennon and Paul J. Olscamp, (Cambridge: Cambridge University Press, 1997). 18

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In weighing the merits of these competing interpretations, there is one consideration that is decisive: the reason Hume gave for maintaining that ‘Malebranche’s’ view is ultimately inconsistent. That reason is that some thoughts are extended. Without that claim, Hume’s reply that it is as difficult to conjoin an extended thought with an unextended soul as it is to conjoin an unextended soul with an extended thought flounders, because there are no extended thoughts that need to be conjoined with unextended souls. If Malebranche did not accept the crucial premise that some thoughts are extended, then either Hume did or neither of them did. If neither accepted it, then the satire fails. But even if Malebranche did accept it, we have to wonder what a satire of someone who believed (i) that the soul must be locally conjoined with its thoughts and (ii) that some thoughts are extended contributes to the overall purpose of Treatise 1.4.5. The section is entitled ‘Of the immateriality of the soul,’ and the introductory remarks state that while there is much that can be known about the workings of the internal world, the immateriality of the soul is not among those things. This suggests that the remainder of the section should be devoted to demonstrating the inadequacy of arguments for the immateriality of the soul. To be effective, such a project should not be devoted to knocking down straw men. But it is hard to see how satirizing the views of someone who believed both that some thoughts are extended and that an unextended soul must be locally conjoined with its thoughts could be viewed as anything else. There were two prominent immaterialist views in Hume’s day, the view of Clarke, that souls are extended but incorporeal, which has no problem accommodating extended thoughts, and the view of Descartes, that souls are unextended, which can be defended by denying that there are any thoughts that are extended. Those were the views Hume needed to engage. On the account offered in the previous section of this paper, his response to the ‘remarkable’ argument did engage them, and engaged them on the basis of his own, prior commitments. On the account offered by Yolton, Hume did not engage them and instead amused himself with a purportedly ad hominem lampoon of a patently weak position while ignoring the argument many of his predecessors, contemporaries and successors considered to be the ‘Achilles’—the most compelling—of all of the arguments for the immateriality of the soul.

11.6 Excursus: Lessons from Treatise 1.4.5.17–28 After having taken his reply to the Achilles argument as far as Treatise 1.4.5.16, Hume paused a second time, declaring, ‘This gives me an occasion to take anew into consideration the question concerning the substance of the soul.’ The ensuing ‘consideration’ seems to have been intended to deflect the charge that rejecting an immaterial thinking substance is irreligious and hence ‘odious.’ But it provides further evidence for considering Hume’s critique of immaterialism to be entirely sincere and it offers Hume’s most direct engagement with an issue that has been left hanging up to this point—the question of why we should accept that thoughts are ‘beings’ that occupy or occur at locations in space rather than acts that at best refer to spatially located objects.

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The ‘new consideration’ consists of an attempt to show that ‘the doctrine of the immateriality, simplicity, and indivisibility of a thinking substance’ is as dangerous to religion as its opposite. It is ‘a true atheism, and will serve to justify all those sentiments, for which Spinoza is so universally infamous’ (Treatise 1.4.5.17). Over the ensuing paragraphs Hume first gave ‘a brief exposition of the principles of that famous atheist.’ He then turned ‘to show, that this hideous hypothesis is almost the same with that of the immateriality of the soul’ (Treatise 1.4.5.19). That demonstration proceeds as follows: Hume first claimed that, according to Spinoza, extended objects are modes of a simple, indivisible, immaterial substance. He then claimed that, according to the doctrine of the immateriality of the soul, extended ideas are modes of a simple, indivisible, immaterial substance. He finally claimed that the tenability of the doctrine of the immateriality of the soul implies the tenability of Spinoza’s hypothesis. Contrapositively, the untenability of Spinoza’s hypothesis implies the untenability of the doctrine of the immateriality of the soul. Note the premises of this argument, and note the comparison it draws. If Spinoza’s hypothesis is untenable, it is not because external objects are not really extended; it is because the inherence of extended things in an unextended substance makes no sense. But if what makes Spinoza’s position so absurd is its claim that extended objects inhere in an unextended substance, but no thoughts are extended, then there is no comparison to be drawn between the views of Spinoza and those of the immaterialists, and no precedent for Spinozism set by immaterialism. The comparison can only be drawn if it is taken for granted that some thoughts are in fact extended, so that allowing extended thoughts to inhere in an unextended subject sets a precedent for allowing that extended objects could inhere in an unextended deity. Here again, the authorship of the claim that some thoughts are extended is crucial for understanding Hume’s project. Tellingly, Hume did not attribute this claim to any one else, not even Spinoza. Instead, he argued for it. He justified it by invoking two principles: ’tis impossible our idea of a perception, and that of an object or external existence can ever represent what are specifically distinct from each other (Treatise 1.4.5.19) We have no idea of any quality in an object, which does not agree to, and may not represent a quality in an impression (Treatise 1.4.5.21)

According to the first of these principles, the idea of a perception cannot be the idea of an intentional act. If that were the case, the idea of a perception would be ‘specifically distinct’ from the idea of the object of that perception. According to the second principle, impressions must be like objects. In whatever sense a quality is ‘in’ any external object that is at all knowable by us (so that we can have an idea of it), that same quality is ‘in’ an impression in that same sense.—Or if it is not, then we can know nothing of it. So if extension is ‘in’ external objects, it is in impressions in precisely the same sense of ‘in.’ And if color and solidity are ‘in’ external objects, they are ‘in’ impressions in precisely the same sense of ‘in.’ Hume did not attribute these two principles to any one else. Instead, he justified both of them by appeal to a doctrine he had himself asserted in earlier parts of the

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Treatise: that every idea is derived from a preceding impression. His claim was not, therefore, that the views of those who argued for the immateriality of the soul pave the way for claims of Spinoza; it was rather that doctrines established in earlier parts of the Treatise show that the views of those who argued for the immateriality of the soul pave the way for the claims of Spinoza. The analogy with Spinoza follows only because the Treatise establishes something that the immaterialists had not appreciated: that there are thoughts that are themselves extended. Hume’s rejection of the alternative view that thoughts are acts that at best refer to extended objects was made explicit immediately upon completion of his discussion of Spinoza. ‘’Tis the same case,’ he wrote, ‘if instead of calling thought a modification of the soul, we shou’d give it the more antient, and yet more modish name of an action’ (Treatise 1.4.5.26). His chief reason for rejecting the ‘antient yet modish’ account of thought was the following: But betwixt a person in the morning walking in a garden with company, agreeable to him; and a person in the afternoon enclos’d in a dungeon, and full of terror, despair, and resentment, there seems to be a radical difference, . . .At least it must be confest, that having no idea of the substance of the soul, ’tis impossible for us to tell how it can admit of such differences, and even contrarieties of perception without any fundamental change (Treatise 1.4.5.27)

There is a quite profound observation being made here. Hume made it by invoking the example of passions, but it could be even more effectively made by invoking the experience of pleasure or pain. When I feel a passion or a pain, it is incongruous to describe me as performing an act that refers to that passion or pain as its object, as if I, the thinking subject, were somehow different from the passion or pain and this passion or pain had some independent existence that I was merely contemplating. I do not think of the passion or pain; I enjoy or endure it, which is to say that I exist in a different state from the state I am in when not feeling it. My being is differently modified. For Hume all thoughts are like this. None is ‘of’ an object. All are ways of feeling. Heat and cold are no different from pain and pleasure. Color (meaning the raw, phenomenal look of reds and greens that we enjoy when we look at colored objects and that no early modern philosopher took to be qualities of any external object) is no different from heat and cold. But color and tactile impressions like heat and cold are disposed in space to constitute figures of different sizes. So, primary qualities like size and shape are likewise qualities of impressions, albeit of aggregates of impressions, rather than of individual impressions. Hardness, understood as the resistance of component parts to relative motion, and solidity, understood as resistance to compression, have to do with whether shapes retain their shape and size consequent to impact, and so are likewise qualities of aggregates of impressions (cf. Treatise 1.4.4). In the end, there is no quality we can think of that is not a feeling or a quality of an aggregate of feelings, and hence no thought that is not a feeling. Having taken the point this far, Hume proceeded to argue that since an action by definition makes no change to the subject who performs it, whereas all thoughts are feelings, thought could not be an action. This is not a very satisfactory

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dénouement. We might wonder why there could not be acts that do involve some change in the subject.19 However, Hume could readily have substituted a more effective conclusion. The ultimate point he needed to make is not that thoughts must be modifications rather than acts, but that some thoughts are extended and located in space whereas others are not, call those thoughts ‘actions’ or call them ‘modifications’. Having claimed that all thoughts are acts of feeling, not acts of reference, he was in a position to draw this conclusion. (Indeed, the claim that just some thoughts, impressions of pain, are acts of feeling, would put him in a position to draw this conclusion.) For Hume pains, whether understood as acts of feeling or as modifications of my being, are disposed in space, like all other tactile impressions. Substituting the ‘antient yet modish’ name of ‘action’ for that of ‘modification’ does not change this fact; it merely obfuscates it. At least some of the so-called ‘actions’ of the soul occur at different locations and constitute extended, figured aggregates. And if all the acts of the soul are not like this, that is a moot point. It only takes one extended mental state to burst the bubble of an unextended mind.

11.7 The Adequacy of Hume’s Response to the Achilles From considering the sincerity of Hume’s response to the Achilles argument I now turn to considering its adequacy. As noted earlier, Hume may have thought that he had done an end-run around the Achilles. By establishing that thoughts are independent existents that do not depend on, and cannot coherently be supposed to be locally conjoined with either a material or an immaterial substance, he obviated the need to specifically consider the core assertion of the Achilles, that were thoughts conjoined with or inherent in a composite thing, there would be either no part of the composite that has the whole thought or replications of the whole thought in each part. But the Achilles poses a residual problem for Hume. It appeals to the introspectively obvious fact that I, the identical subject, am conscious of multiple items of information. As Bayle put it, I am aware of an entire horse and an entire tree. Hume objected that there is no ‘I’ in which perceptions inhere or with which they are locally conjoined. But taking ‘I’ out of the claim, ‘I am aware of an entire horse or an entire tree,’ still leaves the residual claim, ‘there is a perception of an entire horse or an entire tree.’ Hume did not want to deny that there are such perceptions. When, at the outset of the Treatise, he recognized the perception of an apple as a ‘complex perception’ consisting of the perceptions of a particular color, taste, and smell united together (1.1.1.2) he admitted that there are such things. He therefore needed to account for how, in addition to ‘simple’ perceptions disposed alongside one

19

Cudworth, 831, had in fact claimed that the acts of external things are very different from the act of cogitation, which is not a ‘meer Fridging up and down, of the Parts’ but an ‘Internal Energie’ whereby the subject acts ‘from’, ‘within’, and ‘upon’ itself.

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another in space and succeeding upon one another over time, there could be complex perceptions. The matter is not trivial and it is far from obvious how Hume could resolve it. The matter is not trivial because more is required for the occurrence of a complex perception than the bare occurrence of a number of simple perceptions. As proponents of the Achilles pointed out, if one person sees the horse’s head and another sees the horse’s tail, or one hears the first word of the verse and another hears the second, then even though there are multiple, simultaneously occurring simple perceptions or multiple successive impressions, there may not be a complex perception of a horse or a whole verse. Neither is it obvious what, for Hume, could account for the difference between cases where multiple perceptions compose a complex perception and cases where they do not. A complex perception could not be the consequence of the coincidence of various simple perceptions at a point, since many of the simple perceptions that enter into a complex one do not exist at points in space. (The taste and smell of an apple do not, for example.) Even visible and tactile perceptions can at best be adjacent, not coincident (and the visible can only be adjacent to the visible, the tactile to the tactile, not the visible to the tactile). Neither could complex perceptions be the consequence just of the co-occurrence of simple perceptions at the same time, since I can see only the head of a horse sticking out of the barn door while someone else, whose consciousness I do not share, simultaneously sees the tail of the horse inside of the barn, and since the successive occurrence of five notes played on a flute can constitute a complex perception for me, even though the perceptions are not simultaneous. Hume recognized association (and chance) as ‘bonds of union’ among perceptions. Were ideas entirely loose and unconnected, chance alone wou’d join them; and ’tis impossible the same simple ideas shou’d fall regularly into complex ones (as they commonly do) without some bond of union among them, some associating quality, by which one idea naturally introduces another (Treatise 1.4.4.1)

But, as Hume himself noted, these bonds only hold among ideas, and that is not good enough. What is needed is an account of how simple impressions are bound together to form complex and compound ones. Association not only does not provide that explanation, it presupposes it. When I look at the horse’s head sticking out of the barn door, I form a vivacious idea of its trunk and tail. But I do so only because I have seen entire horses in the past. Without that past experience there would be no basis for the association of a presently perceived horse part with ideas of the remaining parts of the horse. But the question at hand is what makes those past experiences mine rather than someone else’s. I can only say that I have found multiple colored points to be disposed in the shape of a whole horse on numerous past occasions if I have been simultaneously aware of all of those points in that configuration on numerous past occasions. My claim presupposes the community of those points in my past consciousness and does not explain how that community comes about.

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There would be no problem were we to recognize the existence of a subject who has perceptions. Then we could say that what makes certain simple perceptions compose a complex perception is that they are ‘had by’ or contained within the same subject. This is the intuition that lies at the basis of the Achilles argument—that insofar as there is a complex or compound perception there must be an identical ‘I’ that ‘has’ or is aware of or ‘contains’ or is locally conjoined with each of the component simple perceptions. But Hume rejected that answer when he rejected the inherence of thoughts in a mental substance and went on to deny that we have any experience of a self. What he had to offer in its place is not very satisfying. [I]n forming the complex ideas of [a fig and an olive] one of the most obvious is that of their different relishes . . .the taste and smell of any fruit are inseparable from its other qualities of colour and tangibility; and which-ever of them be the cause or effect, ’tis certain they are always coexistent. Nor are they only co-existent in general, but also co-temporary in their appearance in the mind. (Treatise 1.4.5.11–12, my italics)

As already noted, coexistence and co-occurrence are inadequate to explain what binds simple perceptions together to form a compound. And the most charitable thing that can be said about the reference to a contemporaneous appearance ‘in the mind’ is that it only manages to employ the metaphor it ought to be explaining. The question is what makes the visual impressions of the horse’s head and the visual impressions of the horse’s tail contemporaneous in my mind—as opposed to contemporaneous in the minds of different subjects. If there are no minds in which these perceptions inhere, and if each simple perception is different and distinguishable and separable from all the others, then this question lacks an obvious answer.

11.8 A Skeptical Reply to the Achilles The appendix to the Treatise suggests that Hume threw up his hands over a question at least similar to this one, confessing himself unable to reconcile the tenets that all our impressions are distinct, distinguishable and separable, and that none are necessarily connected, with (presumably) the tenet that some of them are collected together in one bundle, others in a different bundle. Hume’s remarks in the appendix have been read as a confession of failure and a reason to reject the science of the mind of the Treatise. They are neither. They expose a problem—the problem of what it is that binds various perceptions together—that is not specific to Hume’s philosophy. Hume was, however, the first person to show us that the standard answers to this problem are obscure or untenable and that the problem is therefore a problem for all of us. To accept that there are other minds is, in Humean terms, to accept that perceptions are gathered together in distinct bundles. They are not bundled in a space, because not all perceptions are in space. Neither are they bundled in time, because the perceptions of different persons co-exist. There must, however, be some relation that obtains among all those perceptions that exist within one bundle and that fails

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to obtain between those perceptions that exist in different bundles. Let us call this the cohabitation relation. Hume’s problem is that he was unable to discover any way of accounting for the cohabitation relation. He could not explain cohabitation by appeal to consciousness. That is, he could not say that what makes perceptions cohabit is that there is an enduring subject who privileged access to them, realized in acts of consciousness or attention. To do that would be to resurrect the view that perceptions inhere in some sort of mental substance—or to invent some other equally unintelligible notion. Neither could Hume explain cohabitation by appeal to location within the confines of some animal body. For, as already noted, not all perceptions have any location in space. But to fail to come up with an explanation for some fact is not the same thing as to be driven into an absurdity. Were we in a position to view the universe of impressions from a God’s eye view, we might have a problem telling which perceptions go in which bundles, and be embarrassed if we can do so without being able to give any account of how we manage to perform this feat. But none of us has this problem. As far as I am concerned, the only perceptions that exist are the ones that exist in the bundle that I call myself. How that bundle came to exist is not a problem for me because I do not create or constitute it; instead, I am constituted by it. What bundles exactly these perceptions together to make me is not a problem for me; instead, that exactly these perceptions are bundled together is a brute fact. Hume taught us that the only difference between taking perceptions to be brute factually gathered together in a bundle and taking them to occur within the consciousness of a subject is that the latter is rather more unintelligible than the former. The former hypothesis sticks to the facts, and does not seek to account for them by appeal to jargon whose ultimate unintelligibility is concealed only by the fact that it has become familiar. This is the real answer to the Achilles argument to be drawn from Treatise 1.4.5. It is an answer that consists in granting the entire argument that matter cannot think, but then going on to assert that nothing else can think either. A point cannot think. Neither can a spirit. At the very least, these things cannot have all of the thoughts that we experience ourselves to have. But while nothing can think, our thoughts nonetheless exist, each in its own right, independently of the others. Moreover, some of them (supposing there are others) are somehow brute factually compounded in one mind or bundle. We have no good explanation for how this happens, though we know that it does. We are left with a problem, and left skeptical of all the proposed solutions to it. I suspect that Hume did not consider this to be an altogether uncongenial result. The science of the mind stands on a brute-factual basis. For whatever reason, certain perceptions cohabit, and we can study their interactions in accord with principles of association. But we cannot carry our researches so far as to understand what makes them cohabit or reach any decision about the immateriality or consequent immortality of a self. If this be not a good general reason for scepticism, ’tis at least a sufficient one (Appendix, 10) What is known concerning [the internal world] agrees with itself; and what is unknown, we must be contented to leave so. (Treatise 1.4.5)

Chapter 12

Kant and Mendelssohn on the Implications of the ‘I Think’ Brigitte Sassen

In the Transcendental Dialectic of the Critique of Pure Reason there is a section called ‘On the Paralogisms of Pure Reason.’1 Kant described transcendental paralogisms as errors in reasoning that have a ‘transcendental ground’ (A341/B399). More specifically, such arguments are illegitimate or fallacious because they rest on an equivocation between the transcendental and the empirical domains. While we may be entitled to posit certain transcendental concepts – for instance, the Cartesian ‘I’–we are not entitled to make claims about them that are supported by what we perceive empirically, for instance, that through introspection we experience ourselves as persisting through time in a way that would justify asserting that the soul (thinking being) is a substance (A343-3/B400-1). In this paper, I treat one of those apparent misuses of reason: the argument of the ‘Second Paralogism of Simplicity’ primarily as it appears in the first edition of the Critique of Pure Reason (A351–61) and I deal with Kant’s discussion in the broader historical context in which it appeared. Although Kant did not name specific authors of rationalist fallacies, he most likely had the rationalists of the early modern period (Descartes, Wolff, Baumgarten)2 in mind when complaining about the misuse of reason. In the revised second edition section of the Paralogism, Kant did identify one representative of the tradition, Moses Mendelssohn (1729–1786), by providing

B. Sassen Department of Philosophy, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1 Phone: (905) 525-9140, ext. 23475, Fax: (905) 577-0385 e-mail: [email protected] 1 References to Kant’s Critique of Pure Reason (KrV) are to the pagination of the first and second original editions identified as A, B respectively and will appear in the body of the text. All translations are my own. The paralogisms are at KrV, A341–405/B399–432. References to Kant’s other critical works are to the pagination of the Prussian Academy edition (29 + volumes; Berlin: deGruyter and predecessors, 1900) cited as ‘Ak’, with volume and page numbers following. 2 See Henry E. Allison, Kant’s Transcendental Idealism: An Interpretation and Defense, Revised and Enlarged Edition (New Haven: Yale University Press, 2004), 333. The link to Leibniz is made particularly by Patricia Kitcher, Kant’s Transcendental Psychology (New York: Oxford University Press, 1990), 198.

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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a refutation of his proof for the soul’s permanence.3 Mendelssohn was the prime figure of the German Enlightenment at the time and someone with whom Kant claimed a ‘certain philosophical kinship.’4 This makes his 1767 Phaedon, which advances an intricate argument for the immortality of the soul, the ideal counterpoint to Kant’s text.5 But the situation is more complex than just indicated. On the one hand, Kant was critical of Mendelssohn, as is evident from the refutation (see note 3) and also from his treatment of the sort of argument Mendelssohn advanced in the Second Dialogue of the Phaedon. In the A edition Second Paralogism, Kant called this the ‘Achilles of all dialectical inferences of the pure doctrine of the soul’ (A351) and the argument is the Achilles argument that is the main focus of this volume. (More specifically, it is the Broad Achilles in combination with the Narrowest Achilles.) On the other hand, Kant himself advanced at least a portion of an argument like the one we find in the Second Dialogue of the Phaedon in the Transcendental Deduction of the Categories in the second or B-edition of the Critique.6 Mendelssohn, accordingly, had an important role to play with regard to the Critique of Pure Reason.7 Given the complex interrelationship I have briefly sketched, I shall proceed as follows: Beginning with the arguments for the incorruptibility of the soul, I shall treat Mendelssohn’s argument in the First Dialogue of the Phaedon and Kant’s Refutation of it in the second edition of the Critique. Here it will become quickly evident that Kant misinterpreted Mendelssohn’s argument since the latter offered an answer to Kant’s later objection which Kant seems to have failed to notice or appreciate. Since Mendelssohn did not equate the soul’s incorruptibility with its immortality, I shall then turn to his refutation of materialism in the Second Dialogue of the Phaedon where immortality in particular was established. This will allow me to demonstrate how a portion of the argument is echoed in the Transcendental Deduction of the Categories, but also quite severely criticized in the A-edition Paralogism. To indicate how this debate continues into the 19th century, I shall conclude with Johann Gottlieb Fichte’s critique of Kant. The Phaedon was published in 1767, the first edition of the Critique appeared in 1781, the second in 1787. I will begin with the 1767 text, turn to the 1787 one, return to 1767, this time to the Second Dialogue, proceed to the Transcendental Deduction of the Categories from the 1787 version of the Critique, continue with the A-edition Second Paralogism of 1781 and end with the 1797 version of Fichte’s Wissenschaftslehre. My aim is to capture the intricate connection of these arguments 3

This is the ‘Refutation of Mendelssohn’s Proof for the Permanence of the Soul,’ B413–18. Manfred Kuehn, ‘David Hume and Moses Mendelssohn,’ Hume Studies, XXI/2 (November 1995): 214. 5 On this point see also the Guyer/Wood translation of the Critique (New York: Cambridge University Press, 1998) 738, note 24. 6 See KrV B130–140. 7 An account of Mendelssohn’s influence on Kant although one that does not pay particular attention to the Phaedon can be found in Paul Guyer, ‘Mendelssohn and Kant: One Source of the Critical Philosophy,’ Philosophical Topics, 19/1 (Spring 1991): 119–152. 4

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rather than tell a story about the history of thought. Nonetheless, the actual historical sequence bears mention and should be kept in mind throughout.

12.1 The Incorruptibility of the Soul The Phaedon, as the title implies, took its cue from Plato’s dialogue by the same name. Like Plato, Mendelssohn was here concerned with the immortality of the soul, understood, as Mendelssohn specified, as ‘the power to think and to will.’8 For Plato, this concern was set in the context of Socrates’s impending execution. For Mendelssohn, it arose from his interest in Socratic dialogues in general and, as Altmann notes, the desire to put the arguments for the immortality of the soul into the mouth of a ‘pagan’. This was ‘in order to be absolved from having recourse to revelation.’9 As Mendelssohn himself explained matters, the project was to base the argument not on religious belief, which is necessarily variable and tied to a specific time and culture, but on rational deliberation.10 As such he believed it to hold for everyone, not merely for those who might happen to share a particular set of religious convictions. If the soul (the power to think) is to be immortal, it first has to be shown to be incorruptible or permanent and, again following Plato, this is the first point Mendelssohn set out to establish. As already noted above, Mendelssohn did not simply equate the permanence or incorruptibility of the soul with its immortality. Even if the former can be demonstrated, one still has to consider how it might continue after the death of the body. To be deemed truly immortal, the soul must not just continue after the demise of the body, it must also retain its rational faculties. So the point will not just be that it is permanent – that it continues after the death of the body – but it will also have to be established how it is permanent – how it continues. The first point is established in the First Dialogue, the second point is principally dealt with in the Second Dialogue.

12.1.1 Mendelssohn’s Argument The argument Mendelssohn presented for the thinking being’s (soul’s) permanence is quite ingenious. He offered separate treatments of the death of body and soul, but each was considered against the background of a common view of the nature of change, a view that echoes pronouncements found both in Plato and in 8

This definition appears in the Appendices to the 2nd and 3rd editions of the Phaedon. Moses Mendelssohn, Phaedon oder über die Unsterblichkeit der Seele in Gesammelte Schriften, Fritz Bamberger and Leo Strauss eds. (Friedrich Frommann Verlag, 1972), 133, 146. Further references to this text are to this edition and will appear in the body of the text. All translations are my own. 9 Mendelssohn to Abbt, 22 July, 1766, cited in Alexander Altmann, Moses Mendelssohn: A Biographical Study (University of Alabama Press, 1973), 147. 10 Altmann, Moses Mendelssohn, 151.

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the works of Leibnizian natural philosophers. According to this view, ‘whatever is changeable . . . cannot remain unchanged but must be in a state of constant change’ (Phaedon, 64). Change is a gradual process requiring three steps: ‘a prior state of things, which is to be altered, a subsequent state which is opposed to it, and a transitional stage’ (Phaedon, 63). Importantly, there are no sudden jumps, the subsequent state, even if it seems to be the result of a radical change, must have been prepared through gradual transformation. (This ‘principle of continuity’ has an important role to play at later stages in the argument.) Change, in other words, is alteration of something that endures throughout the process, not absolute generation or destruction (Phaedon, 67). Applied to the body, death happens as follows: since the body is divisible into parts, it dies through disintegration and transformation. That is to say, during disease or as the result of age (here identified as the most natural of diseases – [ibid]), the ‘machinery’ of the body is dissolved into its ‘smallest parts’ and, significantly, each of these smallest parts undergoes further change and transformation. The point is that [t]hrough the dissolution of the animal body, nothing is lost. Each of the dispersed parts continues to exist and to affect [others], to suffer, to remain in a composite or to be separated, until through infinite transformations they are changed into parts of another composite. Some become dust, some become moisture, this one ascends in the air, that one is transformed into a plant, changes from the plant into a living animal, leaves the animal in order to serve as food for a worm. (Phaedon, 67–8)

Thus, even though a given body or composite may die, nothing disappears. Everything undergoes a process of dispersal and transformation. Nothing is altogether annihilated.11 This process can be applied to the soul only with difficulty. The most immediate problem here is its simplicity, which has not yet been established but serves as a working hypothesis in this argument (the simplicity and immortality proper of the soul is the subject matter of the Second Dialogue).12 Being simple, it is not divisible into parts and thus cannot undergo a process of gradual disintegration and transformation. Accordingly, a different account of its death would have to be provided. Here Mendelssohn considered two alternatives: either the soul dies by being gradually transformed into something else, as the body is, or it dies suddenly. For it to die suddenly, there are again two alternatives: it is naturally destroyed or it is destroyed through an act of God. It quickly turns out, however, that both of these alternatives are unacceptable. The principle of continuity dictates that the natural process of death involves a gradual transformation, not a destruction. The soul, accordingly, cannot vanish through sudden natural destruction. Even though God 11

This seems to have been a point of some contention. In the Appendices to later editions of the text, where Mendelssohn responded to his critics, he emphasized that death is not, as some seem to have assumed, destruction (Zernichtung). Instead it must be regarded as transformation from one state to another, for instance, from hot to cold, from hard to soft, from beautiful to ugly etc. (Phaedon, 135, 148). 12 On this point see also the Appendix to the second edition, Phaedon, 133.

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would conceivably be exempt from this requirement, Mendelssohn insisted that this possibility must be rejected as well. It is simply impossible to imagine that God would destroy what he had created (Phaedon,70). Socrates and his interlocutors agree that this point does not even have to be demonstrated. The first alternative – that the soul is gradually transformed into something else – is a more interesting one. The question now is whether the soul would be destroyed with the decay of the body (Phaedon, 70–1). This is an eminently reasonable question since the soul, after all, needs the sensory organs for input and the intellectual capacities for thought. Take away these abilities and the soul must surely vanish also. The advantage of this alternative is that the destruction of the soul would go hand in hand with that of the body; it would be a gradual transformation of something into nothing (or rather into something else) and the principle of continuity would not be violated. But Mendelssohn was reluctant to accept this possibility, leading the way for the subsequent refutation of materialism. The main reason for this reluctance is the prevailing (and yet to be demonstrated) hypothesis that the soul is simple. As we have already seen, its simplicity entails that unlike the body it cannot be divided into parts that come to be transformed into something else. Mendelssohn then took up a possibility that Kant, as we will see, must have failed to notice. This is that the death of the body is accompanied by a ‘gradual decrease of its [the soul’s] powers’ (Phaedon, 71). This option would definitely appeal to the materialist, but it is also one Mendelssohn rejected (though not, as we shall see, Kant). He claimed, importantly, that ‘the last step in the destruction, however long in the future it would happen, would still involve a leap’ (Phaedon, 73). It would be a leap from the state of being to the state of non-being and given the principle of continuity, such a change is impossible. The soul, accordingly, is permanent; it cannot be corrupted into nothing. Some power of consciousness, however minimal, must remain because if it were to disappear altogether, there would have been a discontinuous change of state. Mendelssohn’s argument appears to be a particularly reasonable one. Anyone who accepted the principle of continuity and who also thought that the soul or thinking power must be something over and above the (material) component parts making up the body would have a difficult time refuting it. However, Mendelssohn seems to have realized that the immaterialist view of thought was by no means an established point. Hence the extensive refutation of materialism in the Second Dialogue.

12.1.2 Kant’s Refutation It is not clear why Kant added the ‘Refutation of Mendelssohn’s Proof for the Permanence of the Soul’ to the B-edition of the Critique. While he set out and discussed four distinct Paralogisms in A, these are lumped together in B and presented much more briefly. Since Mendelssohn had the Phaedon sent to Kant when it first came out,13 Kant must have seen it well before the publication of either edition of the 13

Mendelssohn to Nicolai, 7 May, 1767, cited in Altmann, Moses Mendelssohn, 148.

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Critique, so it cannot have been the case that he just encountered it when he was working on the B-edition. Moreover, since as will be obvious in a minute, Kant misread Mendelssohn’s text, he was probably working from memory, suggesting that he had not recently read the text. What is more, although Kant had the A-edition of the Critique sent to Mendelssohn in 1781,14 the latter reported that in view of advancing age and ill health, he had difficulties providing the requisite examination, though in 1783, he still hoped to be able to do so at a later point.15 That point did not come; indeed, by his own account, he had ‘not been able to study the Critique,’16 – much, it must be added, to Kant’s disappointment.17 So it can’t have been that Mendelssohn read the book and made a specific comment about the Paralogisms inviting refutation. Differently put, just why Kant bothered with Mendelssohn in 1787 is mysterious. It might be that his treatment of the substance argument in the Anfangsgründe brought it to mind.18 The central point of Mendelssohn’s argument, as noted in the previous section, hinges on appeal to the principle of continuity and its implication that the soul must be permanent because its death or disappearance would have meant an illegitimate jump or ‘leap’ from something to nothing (Phaedon, 73), a change, in other words, from being to non-being. Kant could have questioned this principle, although it is unlikely that he would have disagreed with it. Alternatively, he could have questioned Mendelssohn’s view that we cannot have continual diminution to zero.19 Finally, he could have disputed the presupposition of simplicity. But Kant did none of these things. True, given the critical philosophy, he did not think that we are entitled to maintain anything about the soul (including that it is simple), but he did not bring this problem up here.20 Instead, he ‘refuted’ Mendelssohn’s argument by introducing the very idea of death by means of a gradual loss of power (or ‘elanguesence’ as Kant put it [B414]) that Mendelssohn had considered and rejected – and he did so while suggesting that Mendelssohn had overlooked the possibility, a charge that is falsified by a cursory reading of Mendelssohn’s text.

14 See Kant’s letter to Marcus Herz, 1 May 1781 (Immanuel Kant, Briefwechsel, Otto Schöndorfer and Rudolf Malter eds. 3rd ed. [Hamburg: Felix Meiner Verlag, 1986], 191–193). Here Kant told Herz that of the four early samples of the book destined for Berlin, one was to go to Mendelssohn. 15 Mendelssohn to Kant, 10 April 1783. (Kant, Briefwechsel, 213). 16 Frederick C. Beiser, The Fate of Reason: German Philosophy from Kant to Fichte (Harvard University Press, 1987), 105. 17 Kant to Garve, 7 August 1783. (Kant, Briefwechsel, 230). 18 The Anfangsgründe or Metaphysical Foundations of Natural Science, were published in 1786. This version of the argument appears in Ak, IV, 542–543. Both versions of the argument are discussed by Lorne Falkenstein, ‘A Double Edged Sword? Kant’s Refutation of Mendelssohn’s Proof of the Immortality of the Soul and its Implications for His Theory of Matter,’ Studies in History and Philosophy of Science 29/4 (1998): 561–588. 19 This point has been questioned by, among others, Bennet. See Jonathan Bennet, Kant’s Dialectic (Cambridge University Press, 1974), 58. 20 This is an issue to be taken up by the first edition to be discussed in the next section of this paper.

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The idea underlying Kant’s refutation is the distinction between extensive and intensive magnitude. Whereas whatever has extensive magnitude – matter, for instance – is divisible into parts, intensive magnitude – of sensation, for instance – does not require divisibility but refers to degree of intensity of the sensation. The standard example here is the sensation of pain. As we know, pain comes in degrees and, fortunately, the intensity of a specific pain sensation tends to decrease or dissipate with time. The point here is that whereas the destruction of matter entails a loss (some part of it will have to be separated), the decrease of a sensation or anything else that has intensive, not extensive, magnitude does not. The decrease of intensive magnitude does not involve a loss of substance whereas the decrease of extensive magnitude does.21 For Kant, whatever the soul or thought might be in itself, we can know it only in virtue of our empirical consciousness of it. Since that consciousness is consciousness of a thing that exists only in time, it has only intensive, not extensive magnitude. Since intensive magnitude can gradually diminish and even become nothing without loss of substance, and, according to Kant, without the sort of radical jump in kind that Mendelssohn thought impossible, the soul can be destroyed or gradually vanish through loss of the power of thought even while the substance remains. Accordingly, he concluded that ‘the permanence of the soul as merely an object of inner sense remains unproven, and is indemonstrable’ (B415). This must not be read as an assertion that the soul is not permanent, but only as the claim that its permanence had not been proven, and could in fact not be proven. Kant did not advance this critique in order to show that the soul was not simple and that it was not permanent; his ultimate point was that such things cannot be known and he questioned Mendelssohn’s argument to make this point. The main difficulty with Kant’s refutation is that its central point, viz., that the loss of intensity could continue to zero is precisely the point Mendelssohn contested (because for him it would still involve a violation of the principle of continuity), and it is interesting that Kant did not consider this. Since he did not, he missed the point of Mendelssohn’s argument. Rather than focus on the gradual and ultimately fatal loss of intensity, he should have questioned Mendelssohn’s claim that we cannot have continual diminution to zero.

12.2 The ‘I Think’ and Achilles: Refutation of Materialism Having established the permanence of the soul to his (though not to Kant’s) satisfaction by the end of the First Dialogue, Mendelssohn has Socrates and his interlocutors turn to its immortality. Although it has by now been established that a simple soul is incorruptible, or that it continues after the death of the body, this is not regarded as sufficient to establish its immortality. To be truly deemed immortal, it has to be rational even after the death of the body. The possession of a minimal capacity for 21

See Falkenstein, ‘A Double-Edged Sword,’ 561–563, especially note 3.

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representations or consciousness is not enough. Cebes in particular was worried about the possibility that with the death of the body the soul ‘would sink into a kind of sleep or brooding’ (Phaedon, 83). ‘An irrational existence,’ he argued, ‘is even farther away from the immortality for which you hope, than the happiness of an animal is from the happiness of a spirit that recognizes God’ (ibid).22 And, of course, it still needs to be established that the soul is in fact simple. In the Second Dialogue, Mendelssohn addressed this second issue in the context of a refutation of materialism. The working hypothesis now is that the soul is an aggregate of material parts, like the body, and this is gradually refuted. At the end of the Dialogue, Mendelssohn noted with some satisfaction that ‘from the presupposition [that the soul is a property of the composite] and through a series of rational inferences, we have demonstrated the opposite proposition, namely that sensation and thought are necessarily properties of the simple and not of the composite.’ (Phaedon, 98). Since the simple has been shown to be permanent, ‘sensation and thought’ must be as well and Mendelssohn thought that the immortality of the rational soul had been established.

12.2.1 Mendelssohn’s Analysis of Emergence The argument (of the second part) has three main steps with the Achilles argument emerging at the end. Mendelssohn has Socrates consider, first, those qualities that emerge in a composite as a consequence of the arrangement of its component parts – qualities such as symmetry, harmony, and beauty. Mendelssohn’s consideration of these sorts of emergent qualities marks a shift from the primacy of the object of thought to the primacy of the subject. The combinations (order and harmony of parts) that we find in objects cannot be a function of the objects that exhibit them; rather they must be a function of the subject, which emerges as responsible for the combinations. The subject with its power of thought, however, cannot be so produced. It cannot emerge as the result of an act or acts of combination or unification producing ‘order and harmony of corporeal component parts’ (Phaedon, 93). Second, Mendelssohn proceeded to consider the derivative forces that emerge in a composite as a consequence of the manner in which the primary forces of its components are modified through their mutual interaction within the composite. This second option is further divided into two cases: cases where the emergent powers are radically unlike the primary powers in the component parts, and cases in which they are alike. In considering the first of these two sub-cases, Mendelssohn again charged that these sorts of emergent powers require thought to be perceived. Thought itself therefore cannot be an emergent power of this sort. The last case is rejected by appeal to the argument that Kant latter dubbed the Achilles, which investigates whether thought could be produced from a combination of similar component parts; in particular, it considers whether powers of representation could result from aggregates 22

See also Altmann, Moses Mendelssohn, 154.

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of component parts that each possess such a power. Here the question was whether the various mental activities of the thinking subject could be distributed among the material component parts of the body. By the end, materialism has been refuted and the soul has emerged as a simple (and immortal) substance. Consider the first point. A composite of one sort or another, a house or a musical composition for instance, consists of the component parts i.e. musical notations and building materials, and the ‘manner in which they are combined’ (Phaedon, 91). Although the order of the component parts and the consequent effect of that order (a harmonious, even beautiful melody, for instance) seems to be a property of the object, Mendelssohn quickly shifted to the insight that it is a function of the subject, in particular, the power of thought. In other words, to get properties like ‘beauty, symmetry, and harmony’ the component parts of the object must be brought into combination; they must be compared and held together, and this is something that can only be done by the mind. As Mendelssohn eloquently put it: ‘[w]ithout the contribution of a thinking being – without any comparison or contrast of its manifold parts, the most regular building is a mere pile of sand, and the song of the nightingale is no more harmonious than the sqawk of the night owl’ (Phaedon, 92). Now, we might ask exactly what the thinking subject contributes to this process. On Kant’s account, the thinking subject contributes an awareness of the relations between the individual parts and of the sum of those relations. This awareness, in turn, is an expression of the power of judgment and is ultimately bound up with Kant’s account of the intellectual conditions of the possibility of experience – conditions, interestingly, that for Kant are ultimately expressed in terms of what is required to bring a manifold to a ‘unity of apperception.’ Mendelssohn’s view is further remarkable in light of Kant’s account of beauty in the Critique of Judgment (1790). Beauty, Kant argued there, is not a property of the object deemed beautiful but is entirely a function of the judgment of taste.23 Judgments of taste, in turn, or judgments in general, are made by the subject in virtue of the power of thought.24 Of course, for Kant this position follows necessarily from the critical approach: once the shift from the primacy of the object to the primacy of the subject has been executed, it is not difficult to conclude that the arrangement of the component parts of an object that says that the object is beautiful (or has any other complex property) is made by the subject (in virtue of the conditions of the possibility of experience). It is surprising that Mendelssohn could arrive at this conclusion without having had to perform the Copernican Revolution. For him, it has to have been the case that the subject, having executed a process of comparison and contrast, would have contributed the order etc. of the component parts. Having established that the mind or power of thought (the subject) is responsible for the various activities at the ground of the ordered composites that constitute 23 Kant made this point in the Analytic of the Beautiful of the Critique of Judgment. See particularly §8 (Immanuel Kant, Kritik der Urteilskraft, in Ak V, 213–216). 24 On Kant’s notion of judgment see Béatrice Longuenesse, Kant and the Capacity to Judge: Sensibility and Discursivity in the Transcendental Aesthetic of the Critique of Pure Reason (Princeton University Press, 1998).

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nature, Mendelssohn proceeded to investigate just what the mind/subject is. The first point that is established here is that the thinking being (mind or soul) cannot be the product of combination. The reason for this is perfectly straightforward and follows from what has already been established: the subject cannot produce itself.25 For the thinking subject to be an aggregate or the product of acts of combination, accordingly, there would have to be something else responsible for these acts. That thing could only be a mind that, on pain of generating an infinite regress, could not possibly be material. Even though the argument so far seems to establish that the thinking subject is not an aggregate, Mendelssohn was not yet satisfied. The ‘capacity to sense and think may not lie in the . . . order and harmony of the corporeal component parts’ (Phaedon, 93), he continued, but it may still be an emergent power. Rather than result from the way the component parts are ordered, it may result from the way the primary powers of the component parts are ‘hemmed in,’ as he liked to put it, by the powers of the surrounding parts, resulting in capacities to produce effects significantly different from effects that might be observed in the individual component parts. This takes us to the second point in my catalogue of tasks. Investigating emergent powers, Mendelssohn turned first to those that are different from anything found in the component parts. Compound colors (like orange and green, which are radically different from the red, blue, and yellow primary colors that might be supposed to compose them) are presented as an example of such phenomena (Phaedon, 95). The point here is both that the powers of the component parts are different in isolation from what they are in combination, and that this is something that appears so only to the soul of the thinking/sensing being. Mendelssohn’s description recalls the notion of secondary qualities. Even though the component parts are not changed through the combination, they appear different in combination to ‘the thinking being who cannot clearly differentiate them’ (Phaedon, 95). So this is the case of a whole with component parts/powers that are different in isolation from what they appear to be in combination. Or consider a different example that does not involve secondary qualities. Take the difference between syllables and the sentence they make up. Even though syllables might be like the sentence in the sense that both can be heard, this is not a relevant similarity. A syllable and a sentence are relevantly dissimilar. What matters here is that the syllable is not meaningful, the sentence is (Phaedon, 94). Both examples are instances of unities that emerge from component parts that do not appear to have the power, individually, to produce anything like the effect produced by the composite. As before, the soul cannot be such a power. As Mendelssohn noted: ‘[t]he synthesis of simple powers, from which a different power emerges, is the act of a thinking being, to whom the powers seem different than they really are. So it is impossible for a thinking being itself to arise from such a synthesis’ (Phaedon, 95–6).

25

This is an important point in view of the discussion of Fichte in the final section of this paper. Fichte did argue that the thinking ‘subject’ produces itself, though not in virtue of the order and harmony of its component parts.

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Recall that the working hypothesis of the dialogue is that the soul is an aggregate or, as Mendelssohn put it ‘that it is the power of the combined’ (Phaedon, 94). So far, this has proven not to be the case. It has been shown that it cannot emerge as a function of the order and harmony of its parts, and it has been shown that it cannot be an emergent power arising from the combination of component parts that do not themselves have that power. Differently put, representative powers cannot emerge from the non-representative ones.26 But Mendelssohn was still not satisfied and with good reason. At this point, it has only been established that the power of thought cannot arise from a synthesis of components parts that lack that power. The question remains whether it could arise from the synthesis of ones that have that power, from a synthesis, that is, of a multiplicity of representative powers. To make this question compelling, Mendelssohn considered whether the non-material components of thought could be located in different parts of the material body. This argument and its implications Kant was to dub the Achilles. This is the question, ultimately, of whether the thinking subject could be divisible (the ‘Narrowest Achilles’).

12.2.2 Achilles The specific context in which the Achilles problem emerges in Mendelssohn’s Phaedon is the status of the thinking subject. Is it simple or could it be a multiplicity? It has been established that if the thinking being is an aggregate or multiplicity, it must be composed of like parts – ‘the powers of the component parts must be similar to the power of the whole and must be powers of representation’ (Phaedon, 96). However, it must still be determined whether the conditional aggregate status of the thinking being is to be accepted or rejected. Is it a composite or is it simple? The stage has been set for the Achilles discussion with the working hypothesis that the thinking being is a composite. The first thing that is observed here is that ‘in our soul there is an almost infinite number of concepts, cognitions, inclinations and passions, which occupy us continuously’ (Phaedon, 96). This, in turn, gives us two possibilities: either these activities are dispersed among the parts of the soul or there is one part that has or unifies all of them. The first alternative is deemed impossible, ultimately because the activities would then be unconnected. Simmias added: ‘all the representations and inclinations of the spirit are so intimately connected and unified that they must necessarily reside in some place together in undivided fashion’ (ibid). This is then confirmed by Socrates who claimed: ‘[w]e would be unable to remember, to reflect, to compare, to think, indeed, we would not even be the person that we were a moment ago if 26 This is a central point in Fichte’s Wissenschaftslehre of the 1790s. According to Fichte, the main fault of dogmatists (among whom he included Kant) was that they separated thinking and being and had difficulties bringing them together again. Ultimately, the intellect and the thing occupy ‘different worlds between which there is no bridge.’ J. G. Fichte, An Attempt at a New Presentation of the Wissenschatslehre, in Daniel Breazeale, tr. and ed., Introductions to the Wissenschatslehre and Other Writings (1797–1800) (Indianapolis: Hackett, 1994), 26.

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our concepts were distributed among many [parts] and if they were not to be found in some one location in their clearest connection’ (ibid). This will be an important point when we turn to Kant in the next section. From here, Mendelssohn has Socrates (and Simmias) move immediately to the conclusion that there must be at least one simple substance that is responsible for the unification of all mental activities. This substance must be unextended because whatever is extended is divisible, and whatever is divisible is not simple. They call this substance the soul (Phaedon, 97). As we already know, the soul is incorruptible. Since it performs mental activities (representing, conceiving, cognizing and so on), its immortality (as conceived by Mendelssohn) seems to be assured. Still, a further refinement of the concept of soul followed. The question that arises is whether there is only one such simple substance in the body or whether there could be many. If there were many, then each of them would have to contain all of the representations and would have to be just as ‘clear, just as true, just as perfect as the representations of the whole’ (ibid). This assumption of a multiplicity of equally perfect simple substances in a body is rejected as excessive (Phaedon, 98). As a consequence, if there is a multiplicity of thinking substances in the human body – which Mendelssohn did allow – then one has to be the most perfect. And ‘[t]his simple substance, which is unextended, has the powers of representation, is the most perfect among the thinking substances, which live in me, and which encompasses all concepts of which I am conscious in greatest clarity, truth, and certainty etc, is that not the soul?’ (ibid). The conclusion of all of this is obvious. Having started with the materialist hypothesis, Socrates and Simmias must accept the opposite conclusion: the soul must be something perfectly simple and indivisible; it is not a composite of parts. And since, as per the First Dialogue, it has already been established that a simple substance cannot be destroyed, the immortality of the thinking soul seems to be assured. Considered on its own, this seems to be a compelling argument. The thinking substance cannot be material because if it were, it would be dispersed and there would be no guarantee that one part holding a portion of the thought would be connected to another. Alternatively, if it were material, there would have to be some (immaterial) simple substance holding it all together. The commitment to a single thinking substance does seem quite compelling. At the same time, when this commitment is linked to immortality, it becomes rather speculative. The argument is that thought is the property of the simple, not the combined, so by implication, it must continue after the death of the body. By this reasoning, the soul, being a simple thinking substance, must be permanent and thus immortal. But the actual mechanism of this immortality is mysterious. Even if we grant that thought must be the property of the simple substance (however conceived), it remains unclear how it could have representations when, upon death, this simple substance is separated from the body. Where would representations originate? Mendelssohn took this question up in the Third Dialogue, and argued there that with the death of the body, ‘the community between the different beings is dissolved, the body ceases to be a tool for the soul, and the soul must follow entirely different laws than it had to follow to this point’ (Phaedon, 103). In other words,

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ultimately we have no idea just what the fate of the soul after the death of the body is, but a discussion nonetheless ensues. The nature and outcome of this discussions are peripheral to the subject matter of this paper, but in view of Kant’s subsequent critique, it is interesting that Mendelssohn should engage in such speculations.

12.3 Kant’s Critique Kant’s critique of the Achilles argument appears in the first edition Second Paralogism in the Critique of Pure Reason, where the Achilles argument is first identified as such. Although Mendelssohn is not explicitly named here – the Refutation of Mendelssohn is appended to the version of the second Paralogism that appeared in the 1787 second edition of the text (see above) – the kind of argument Kant seems to have had in mind in his initial presentation and criticism of the Achilles does fit Mendelssohn’s argument very well. That being said, one does need to be careful here. Kant must have been ambivalent about arguments of this sort. On the one hand, he must have agreed with the presentation of the problem of unity the Achilles argument sought to address; on the other hand, he was more than worried about the consequences that were drawn from it. Indeed, Kant’s presentation of the problem appeared much earlier than the Second Paralogism; it led Kant to the notion of a transcendental unity of apperception and so to an important premise for the argument of the transcendental deduction of the categories. It is only once we see what Kant must have found good about arguments such as Mendelssohn’s – even if he did not explicitly say so – that we can understand the critique of it as an Achilles argument. This being so, in this section, I first turn to some central features of the Transcendental Deduction (as it appeared in B) and then end with a few remarks about the A-edition Second Paralogism.

12.3.1 Transcendental Unity of Apperception Even a cursory look at the second part of the Transcendental Deduction in B (especially B130–140), reveals that Kant’s argument appears to echo Mendelssohn’s argument in the Phaedon to a significant degree.27 Like Mendelssohn, Kant insisted that the unity of some combination (object) is not given, but requires a ‘combination . . . which is an act of the spontaneity of the power of representation’ (B129). ‘We cannot represent anything as connected in the object’ he continued ‘that we have not connected ourselves’ (B130). And like Mendelssohn, Kant insisted that 27 This is a point not generally remarked on in the literature. In his thorough treatment of the Paralogisms, Karl Ameriks, for instance, did not mention Mendelssohn in this connection. See Karl Ameriks, Kant’s Theory of Mind: An Analysis of the Paralogisms of Pure Reason, new edition (Oxford: Oxford University Press, 2000). Remarks on Mendelssohn’s relevance to this chapter are generally limited to Kant’s refutation of Mendelssohn’s argument for the immortality of the soul discussed above.

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this unifying agency must be one, a unity, not a multiplicity: ‘only insofar as I can comprehend the multiplicity of the representations in one consciousness can I call them uniformly mine’ (B134, emphasis mine). If its representations were dispersed among multiple parts, then we could never have knowledge, could not have certainty, or, as Kant continued the demand for unity: without it, ‘I would have a self that would be as multi-colored and diverse as I have representations of which I am conscious’ (ibid). In the Deduction, this commitment to unity is cashed out in terms of the transcendental unity of apperception, which Kant also referred to as the ‘I think’ (B132). In the absence of the transcendental unity of apperception, I might have representations, but this would merely be a haphazard conglomeration that contains no knowledge of an object. To obtain anything more, I must be able to unify these representations and this, Kant argued, requires that I be conscious of myself as holding and unifying all of them. Without this, I could not have objective knowledge.28 Whether or not Kant got these ideas from Mendelssohn, these texts do accord nicely with each other. Note some important points here. Although Kant insisted that the ‘I think’ is an analytical principle, it is also presented as one that is intimately tied to synthesis (B135). The reason for this is not entirely clear, but some reflection reveals that we can get the unity of the empirically given manifold only by way of synthesis. For Kant, the content of our knowledge has to be given (empirical), it is not something that we have or can derive in an a priori fashion. That is simply not a possibility for human knowledge, which is characteristically receptive, acquiring manifold empirically given bits of data through the senses (in space and time). This is precisely why acts of unification or synthesis have to take place, and it is also why we require an Archimedian point, responsible for performing the act while being itself unchanging (B132). Acts of unification by means of synthesis are not analytic or self-evident. They can take place only on the presupposition of the consciousness of the agent as holding all the threads together; they are contingent on the a priori transcendental condition represented by the ‘I think’. Were I to think that I have some pieces of the thread, while others have others, or that some part of me had some of the data and another part has other pieces without any means of bringing them together, then I could only be in a position to unify those data that I possess, and such knowledge as might be obtained from the data possessed by the other beings or other parts of me would be inaccessible to me. I have to have united all of the data, and for that reason my thought that I have done so expresses the fundamental intellectual condition of the possibility of experience. There may be data that is simply inaccessible to me or that I have not yet been given so that my knowledge would as a matter of fact not be complete. The point is that such bits of data as are given to me have to be unified, and I should therefore recognize myself as identical throughout this act of unification. The ‘I’ that is aware of one item must be the same ‘I’ that is aware of the others and so must be equivalent to a single place that holds all the data. 28

Kant made this point particularly with respect to the distinction between merely subjective judgments of perception and objective judgments of experience (B140–142). On this distinction, see Longuenesse, On the Capacity to Judge, particularly Chapter 8. I treat this distinction elsewhere. See ‘Varieties of Subjective Judgments: Judgments of Perception,’ forthcoming in Kant-Studien.

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Kant continued by insisting that the ‘I think’ is not to be equated with the ‘I am’, where that is accompanied by an understanding of what I am (B138). The ‘I think’ (and ‘I am’) is empty of specifics or content; it does not entail the simplicity, permanence, or substantiality of the thinking subject. It must be understood as nothing more (or less) than the transcendental condition that the I, whatever else it might be, is the agent of synthesis. Any knowledge that we might have about the self is available only empirically, and in an empirical manner we can never know whether a thing is essentially simple, or permanent. Empirical knowledge depends on what is given, and for that reason it can never be of what is essential or necessary. It is here that Kant and Mendelssohn parted company, a point Kant brought out in more detail in the A-edition Second Paralogism. The question we have to wonder about is whether Kant overstated his point. Surely, the transcendental unity of apperception does entail the identity of the I in each of its acts. And if it does do that, then more needs to be said about why it should be wrong to infer that it must be simple, and hence incorruptible and immortal, and hence permanent, and hence substantial. Kant was concerned to emphasize that our claims about the ‘I’ cannot be considered the sort of knowledge that is in any sense on a par with the knowledge of objects. The ‘I think’ is a transcendental condition of the knowledge of objects and not among the objects that can be known through the application of this condition. But more needs to be said about what entitled him to this distinction.

12.3.2 Kant’s Critique of the Achilles In the A-edition Second Paralogism, where the Achilles argument made its appearance, Kant struggled to differentiate his notion of a transcendental unity of apperception from the single (and immortal) thinking substance (soul) of the history of philosophy. This is a difficult task for both Kant and the reader. Kant clearly thought the arguments he attributed to rational psychology were deeply flawed. But it is difficult to see why Mendelssohn’s (2nd dialogue) argument is a ‘paralogism’29 in view of Kant’s own commitment to the notion of the transcendental unity of apperception. Kant’s discussion here centers around what he called the ‘nervus probandi’ of the rationalist argument. This is the proposition that ‘many representations must be contained in the absolute unity of the thinking subject in order to constitute one thought’ (A 353). In view of Mendelssohn’s refutation of materialism discussed above, and Kant’s own position on the necessary unity of apperception, this seems to be a reasonable claim.30 Still, Kant proceeded to argue 29 For a brief discussion of the rationalist argument about the simplicity of the soul as a paralogism see Karl Ameriks, Kant’s Theory of Mind, 49–50. It is unfortunate that Ameriks did not explore the link with the transcendental unity of apperception, as I do here. 30 The connection between the argument of the Transcendental Deduction, in particular the transcendental unity of apperception, and the Second Paralogism has been explored by some. Kitcher, for instance, develops a line much like the one I propose here (Kant’s Transcendental Psychology, 200–202). But see Grier, who maintains that ‘there are reasons to think that Kant does not consider

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that it cannot be so regarded. According to him, it is not analytically true, it is not synthetic a priori, and it is not based on experience. To Kant it was obvious that the proposition cannot be empirically demonstrated. Experience can neither establish necessity nor deliver the concept of an absolute unity (A353). It tells us what is the case, perhaps what has been the case, but it cannot tell us what will or must be the case. Experience, accordingly, is insufficient to deliver the ‘nervus probandi’ of the Achilles argument. Similarly, the proposition cannot be synthetic a priori. All Kant said about this, unhelpfully, was that ‘anyone who understands the ground of the possibility of synthetic a priori propositions’ (A353) would not think that this proposition could be a synthetic a priori one. Perhaps more helpfully, one might note that it cannot be synthetic a priori because such propositions are based on appeal to the conditions of the possibility of experience. The proposition of the nervus probandi concerns the thing that thinks in general, and that is not an object of possible experience. Since synthetic a priori propositions involve the conditions of the possibility of experience and the thing that thinks in general is not subject to such conditions, the proposition in question is not a synthetic a priori one. The status of this proposition as analytic presents the greatest difficulty. It is simply not clear just why it should be the case that the proposition is not analytic. The situation is made even more difficult when we recall that in the B-Transcendental Deduction of the Categories, Kant had argued that the ‘I think’ is analytic (B135) and the ‘I think’ seems rather like the proposition considered here. Where the latter calls for the ‘absolute unity of the thinking subject,’ the ‘I think’ calls for the ‘identity of the subject’ (B133). It is the condition that I can ‘combine [given representations] in one self consciousness’ (B134, emphasis mine). Or similarly, I can call representations mine ‘only insofar as I can comprehend their multiplicity in one consciousness’ (B134). And the necessity of the one consciousness, also identified as ‘I think,’ or self-consciousness, or transcendental unity of apperception, is then presented as an analytic proposition (B135). One has to wonder, then, why the proposition of the nervus probandi, which echoes the transcendental unity of apperception, is not an analytic proposition. If these claims are to be consistent, then there must be a difference between the two propositions. This difference concerns what is thought about the ‘I’. Throughout both texts (the B-Deduction and the A-Second Paralogism), the ‘I think’ was presented as both an empty and a logical condition. Understanding just what this means is important. It is perhaps best illustrated by a similar distinction Kant drew between two different ways of understanding the categories. Categories such as those of substance and causality have a merely ‘logical’ sense, but they also

the minor premise of the second paralogism to be exactly the same as the principle of apperception’ (Michelle Grier, Kant’s Doctrine of Transcendental Illusion [New York: Cambridge University Press, 2001], 167). Her reason for this claim is that Kant designates the transcendental unity of apperception as an analytical principle, but denies this in the Second Paralogism. I deal with this problem in the body of this paper.

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have a ‘transcendental’ sense.31 The difference is that the latter is ‘schematized’ in terms of how an object satisfying the category would appear in space and time. So considered merely logically, substance is that which only exists as subject and not as predicate, whereas considered transcendentally substance is that which is permanent in time. Similarly, considered merely logically, cause is that which serves as a reason for inferring the existence of something else, whereas considered transcendentally it is something that precedes something else in time in accord with a rule. Something like this is in the background in Kant’s discussion of the ‘I think.’ The ‘I think’ can be considered merely ‘logically’ as the subject of thought. In this sense it is ‘logically’ simple and identical, where simplicity and identity are ‘unschematized’ notions, not involving a reference to how the object exists in space and time. But the ‘I think’ is also ‘empty’ because we cannot think it under schematized categories. (The core thesis of the Critique of Pure Reason is that only objects given in sensory experience can be so thought.) Consequently any attempt to cash its simplicity out in terms of spatial partlessness or persistence of the same substance over time is illegitimate. Since it is not an object of experience, we cannot cash out our commitment to its simplicity and identity in those terms. As a consequence of Kant’s critique of what he called the Achilles argument, then, we have the following situation. Although the essentially identical synthesizing subject must be presupposed for the possibility of experience, in particular, for the possibility of the unity of thought (which is essential because we begin with dispersed data), we cannot draw inferences about the nature of the subject that is identical through all experience on the basis of the ‘I think’. In particular, we cannot rule out the possibility that this subject may be an aggregate of material parts, organized in such a fashion as to have a merely functional identity over time. Any knowledge of the subject must be produced as any other knowledge is produced. And that requires a process of the synthesis of spatiotemporal intuitions in view of concepts. It requires that the subject be treated as an object. In spite of having the ‘I think,’ we do not have privileged access to the subject. The Achilles argument is so compelling because of the temptation to ignore the distinction between schematized and unschematized categories – a distinction that it took a critique of pure reason to bring to our attention. What could be more deceptively tempting for a pre-critical thinker than a move from the recognition that the identical subject must be at the ground of all our experiences to the inference that this subject must be unchanging over time (thus identical in the sense of the Third Paralogism), and without distinct parts (thus simple in the sense of the Second Paralogism)? All the same, Kant must have been ambivalent about texts like Mendelssohn’s Phaedon. On the one hand, he shared with Mendelssohn the conviction that there must be an essentially simple agent at the root of the synthesizing operations that unify representations and thus produce objective knowledge; on the other hand, he was critical of the inferences that Mendelssohn (and others) drew about the nature of this simple thing/agency. One has to wonder, however, whether Kant was ultimately

31

See A242–244/B300–302; see also B288–293.

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justified in making this complaint, resting as it does on the complex, critical account of a distinction between sensory, spatiotemporal intuition and intellectual synthesis, and between schematized and unschematized applications of intellectual categories. This was not satisfactory to those of his contemporaries who regarded transcendental idealism as spoiled by the vestiges of realism. One of those contemporaries was Johann Gottlieb Fichte (1762–1814).

12.4 Concluding Comments It is striking that in spite of the different philosophical beginnings that we find in Kant and Mendelssohn (transcendental idealism in Kant’s case, rationalism in Mendelssohn’s), there is agreement on the point that there must be a single, simple subject responsible for unifying the data of experience. While they presented their arguments in different ways and don’t agree on the implications of this single subject, they shared the basic commitment to the single subject at the root of experience that we find throughout the history of philosophy. This commitment remained in the absolute idealism we find in Kant’s contemporaries and critics, Fichte in particular. By the late 1700s, Fichte, originally Kant’s defender and student, had become a critic. Like Karl Leonhard Reinhold (1758–1823) before him, Fichte considered the critical philosophy to be insufficiently systematic and set out to remedy this lack.32 Like Reinhold, he thought that this could be done through the introduction of a first principle from which all of the other components of the critical philosophy could be derived. This is where the similarities between the two defenders turned apostates end however. Reinhold introduced a firm factual foundation – the principle of consciousness – and then found it difficult to deduce the remainder of the critical philosophy from it.33 Fichte’s first principle was interestingly different. It centered around the intellect or absolute subject, which he also called the I-in-itself. Significantly, the I-in-itself is not a thing or substance. In the 1797 Introduction to the Wissenschaftslehre, he argued instead that ‘[i]dealism considers the intellect to be a kind of doing and nothing more. One should not even call it an active subject, for such an appellation suggests the presence of something that continues to exist and in which an activity inheres. But idealism has no reason to make such an assumption, for it is not included within the principle of idealism, and anything not included within this principle must first be derived.’34

32 For an account of the role Reinhold and Fichte respectively played in the development of postKantian idealism, see George di Giovanni, ‘The Facts of Consciousness,’ in George di Giovanni and H.S. Harris, tr. and ed., Between Kant and Hegel: Texts in the Development of Post-Kantian Idealism (SUNY Press, 1985), 3–50. 33 The principle of consciousness is that ‘in consciousness representation is distinguished through the subject from both subject and object and is referred to both’ (di Giovanni and Harris, Between Kant and Hegel, 71). 34 Fichte, Wissenschaftslehre in Breazeale, 26.

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Note that by denying the ‘I in itself’ the status of any sort of substance, Fichte neatly avoided the Achilles problem. What is not a substance cannot be put together out of one or more parts. Nonetheless, the ‘I,’ such as it is, is unitary. Fichte maintained that ‘the intellect’s assumed laws of acting are supposed to have their basis in the unitary nature of the intellect itself’ and, as a consequence, ‘these laws must constitute a single system.’35 When it comes to detail the origin of the intellect, the I-in-itself, Fichte claimed that the I posits itself. Here he referred to things like ‘my own act of self-determination’ and claimed that ‘I am, accordingly, an object for myself, an object whose properties, under certain conditions, depend upon the intellect alone, but whose existence must always be presupposed.’36 There is much that is mysterious here. It is mysterious how the ‘I in itself’ receives its representations, and it is mysterious how there could be an ‘I’ that is not a thing or substance bringing itself into existence through its acts. Quite apart from all of that mystery, in view of the subject matter of this volume, the unitary intellect is important. Unfortunately, Fichte was never able to complete the Wissenschaftslehre, that is, the derivation of the entire critical system from the Archimedian standpoint of the non-substantial but acting ‘I in itself’, but the significance of this notion must not be overlooked.

35 36

Fichte, Wissenschaftslehre in Breazeale, 27. Fichte, Wissenschaftslehre in Breazeale, 13.

Chapter 13

Kant on the Achilles Argument∗ William Harper

13.1 Kant’s Discussion of the Basic Achilles Inference Here is what Kant identifies as the Achilles of all dialectical inferences in the pure doctrine of the soul. Second Paralogism: Of Simplicity That, the action of which can never be regarded as the concurrence of several things acting, is simple. Now the soul, or the thinking ‘I’, is such a thing. Therefore, etc. (A351)

Kant does not give the conclusion explicitly. If, however, we take his more explicit rendering of the inference to the claim that the soul is a substance in his treatment of the first paralogism, as our model it would be: I, as thinking being (soul), am simple1

W. Harper Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 85768, Fax: (519) 661-3922 e-mail: [email protected] ∗ I am using Norman Kemp Smith’s translation of Kant’s Critique of Pure Reason. I have found the new translation by Paul Guyer and Allan Wood helpful. I have also consulted Kant’s German text in the Felix Meiner edition. I believe that, for most of the issues discussed here, the Kemp Smith translation is adequate. My references are to the usual A and B page numbers from the first (1781) and second (1787) editions. 1 In the 1st paralogism, which is an inference to the substantiality of the self, Kant explicitly gives the conclusion as, Therefore I, as thinking being (soul), am substance. (A 348; N. K. S., 333) See Section 13.2 below for more on the clear parallel between Kant’s treatment of these two paralogism inferences.

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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This yields the following two premise inference. Premise 1: That, the action of which can never be regarded as the concurrence of several things acting, is simple. Premise 2: Now the soul, or the thinking ‘I’, is such a thing. Conclusion: I, as thinking being (soul), am simple. We shall see that Kant argues that this inference is unsound, even though it is seductively attractive. He tells us that such an inference is a ‘transcendental paralogism,’ a fallacy grounded in the nature of human reason which gives rise to an illusion which cannot be avoided, although it can be rendered harmless.2 He renders it harmless, by pointing out the fallacy, which he identifies as an equivocation between the sort of simplicity that would be needed to make the first premise true and the sort of simplicity that makes the second premise so attractive. Kant opens his critique with the following comment: This is the Achilles of all dialectical inferences in the pure doctrine of the soul. It is no mere sophistical play, contrived by a dogmatist in order to impart to his assertions a superficial plausibility, but an inference which appears to withstand even the keenest scrutiny and the most scrupulously exact investigation. (A351)

By calling this argument the Achilles of all dialectical inferences in the pure doctrine of the soul, Kant likens it to the great champion of the Greeks in their war with the Trojans. Though he was impressively mighty, Achilles had a fatal flaw. Kant’s second sentence further emphasizes the impressively seductive attractiveness that makes him count this inference as a transcendental paralogism. Kant goes on to offer a more detailed articulation of this inference, which he has labeled the second paralogism of transcendental psychology. It is as follows. Every composite substance is an aggregate of several substances, and the action of a composite, or whatever inheres in it as thus composite, is an aggregate of several actions or accidents, distributed among the plurality of the substances. Now an effect which arises from the concurrence of many acting substances is indeed possible, namely, when this effect is external only (as, for instance, the motion of a body is the combined motion of all its parts). But with thoughts, as internal accidents belonging to a thinking being, it is different. For suppose it be the composite that thinks: then every part of it would be a part of the thought, and only all of them taken together would contain the whole thought. But this cannot consistently be maintained. For representations (for instance, the single words of a verse), distributed among different beings, never make up a whole thought (a verse), and it is therefore impossible that a thought should inhere in what is essentially composite. It is therefore possible only in a single substance, which, not being an aggregate of many, is absolutely simple. (A351–352)

The example, of single words of a verse distributed among different beings never making up a whole thought, is quite striking. Kant uses it to illustrate the plausibility

2 See Section 13.3 below for a quotation of Smith’s translation of the relevant passage from Kant’s introduction to the section titled ‘The Paralogisms of Pure Reason’ (A341, B399).

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of arguing that it cannot consistently be maintained that it is a composite which thinks, because . . . every part of it would be a part of the thought, and only all of them taken together would contain the whole thought.

Clearly, the single words distributed among different beings don’t count as sufficiently taken together to contain the whole thought. Kant articulates this paralogism as an appeal to such examples to argue that . . . it is therefore impossible that a thought should inhere in what is essentially composite. It is therefore possible only in a single substance, which not being an aggregate of many, is absolutely simple.

He will raise a number of objections to this famous argument. In paragraph 3, Kant identifies what he claims is the so-called nervis probandi of this argument as the proposition that (UC) if a multiplicity of representations are to form a single representation, they must be contained in the absolute unity of the thinking substance. (A352)

He goes on to assert that this proposition, a strong unity of consciousness premiss, cannot be treated as analytic. For the unity of the thought, which consists of many representations, is collective, and as far as mere concepts can show may relate just as well to the collective unity of different substances acting together (A353)

Kant appears to be suggesting that, since the unity of a thought as a composite representation is a collective unity of the separate representations brought together to make it up, it cannot follow analytically from the concept of a unified thought that it could not relate to the collective unity of several substances acting together. Andrew Brook points out that Kant’s claim here is very much in line with how a functionalist would respond to the argument. Knowing that the parts of a representation need to be synthesized into a single intentional object by a single subject tells us little about what kinds of structure could ‘realize’ a subject with such abilities. (Brook, 167)

This telling point, raised by Brook, makes it clear that there is little hope for treating (UC) as analytic. Indeed, Brook’s point gives good ground to reject (UC) outright. Kant concludes paragraph 3 by asserting that this unity of consciousness claim (UC) cannot be supported as synthetic a priori. Nor will anyone venture to assert that this proposition allows of being known synthetically and completely a priori from mere concepts – not, at least, if he understands the ground of the possibility of a priori synthetic propositions, as above explained. (A353)

The ‘above explained’ possibility of a priori synthetic propositions would include Kant’s accounts of a priori intuitions grounding fundamental propositions about space and time, and (more saliently for the case under consideration) his transcendental deduction of the pure concepts of the understanding, as well as his account of the system of the principles of pure understanding. The reader is, in effect, invited

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to review the transcendental arguments provided in these treatments to see that no such argument can be constructed to underwrite the Achilles inference. Rather than attempting to review the available alternative arguments, we may note that the functionalist point raised by Brook gives good general grounds for agreeing with Kant’s claim that the Achilles inference could not be established by any such argument. We shall see that some of Kant’s later discussion expands on the case for resisting any attempt to construe the most promising candidate, his transcendental deduction of the categories, as support for the Achilles inference. In paragraph 4, Kant dismisses the suggestion that this necessary unity of the subject could be derived from experience. It is likewise impossible to derive this necessary unity of the subject, as a condition of the possibility of every thought, from experience. For experience yields us no knowledge of necessity, apart even from the fact that the concept of absolute unity is quite outside its province. (A353)

The general empiricist point that experience yields no knowledge of necessity counts very heavily against the claim that UC, the necessary unity of the subject asserted in the conclusion of the Achilles inference, could be derived from experience. Kant reinforces this by calling attention to the more specific point that the concept of absolute unity is quite outside the province of experience. These points, if correct, would show that the Achilles argument is unsound, given Kant’s account of knowledge. He provides additional, more detailed, discussion to further back up these rather briefly made points. In his commentary N. K. Smith (1923, 458) takes the next five paragraphs, paragraphs 5–9, to be Kant’s original criticism of the 2nd paralogism argument and sees them as closely paralleling his criticism of the 1st paralogism (of substantiality). Brook (170–177) points out that these paragraphs contain Kant’s account of significant additional factors, which contribute to what he takes to be the seductive attractiveness of this paralogism argument for simplicity. In paragraph 5, Kant articulates a main source of the seductive attractiveness of the Achilles inference. It is obvious that, if I wish to represent to myself a thinking being, I must put myself in his place, and thus substitute, as it were, my own subject for the object I am seeking to consider (which does not occur in any other kind of investigation), and that we demand the absolute unity of the subject of a thought, only because otherwise we could not say, ‘I think’ (the manifold in one representation). For although the whole of the thought could be divided and distributed among many subjects, the subjective ‘I’ can never be thus divided and distributed, and it is this ‘I’ that we presuppose in all thinking.(A353–354)

Brook sees this forceful passage as contributing what he calls the representation argument to the simplicity of the ‘I’ from the following premise: (2) From the point of view of what it would be like to be a subject of representation, we must picture the subject as being one and cannot picture it as a plurality of any sort. (Brook, 171)

This premiss (2) certainly is compelling.

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In paragraph 6, Kant goes on to argue that, though it is compellingly true and suggestive of simplicity of the subject referred by ‘I’, this premise does not afford a compelling argument for that simplicity of the subject. Here again, as in the former paralogism, the formal proposition of apperception, ‘I think’, remains the sole ground to which rational psychology can appeal when it thus ventures upon an extension of its knowledge. This proposition, however, is not itself an experience . . .We have no right to transpose it into a . . .concept of thinking being in general. For we are not in a position to represent such being to ourselves save by putting ourselves, with the formula of our consciousness, in the place of every other intelligent being. (A354–355)

Here Kant, explicitly, cites his treatment of the 1st paralogism. He refers to role of the ‘I think’ in his account of cognition, pointing out that it is not an experience of a self as an object of knowledge. He is suggesting that putting one’s self in place of another is not an experience of any such other intelligent being as an object of knowledge. Kant further clarifies his claim that, even in my own case, the formal proposition ‘I think’ does not count as a concept of my self as an object of knowledge. This point is expanded upon in paragraph 7, Nor is the simplicity of myself (as soul) really inferred from the proposition, ‘I think’ . . .‘I am simple’ means nothing more than that this representation, ‘I’, does not contain in itself the least manifoldness and that it is absolute (although merely logical) unity. (A354–355)

Brook sees this as specifically addressing an appeal to self-awareness which may be thought to provide additional support for the paralogism argument to simplicity. (3) If I am aware of myself as subject, I must appear to my self to be one and cannot picture myself as a plurality of any sort. (Brook, 173)

In paragraph 8, Kant summarizes his objection to arguments to the simplicity of the subject from either or both of premisses (2) and (3). Thus the renowned psychological proof is founded on the indivisible unity of a representation, which governs only the verb in its relation to a person. . . .Nothing, indeed, can be represented that is simpler than that which is represented through the concept of a mere something. But the simplicity of the representation of a subject is not eo ipso knowledge of the simplicity of the subject itself, for we abstract altogether from its properties when we designate it only by the entirely empty expression ‘I’ . . . (A355)

This objection is expanded upon in paragraph 9, where the parallel to his criticism of the first paralogism is, again, stressed. But this concept, as also the proposition [that I am substance], tells us nothing whatever in regard to myself as an object of experience, since the concept of substance is itself used only as a function of synthesis, without any underlying intuition, and therefore without an object. It concerns only the condition of our knowledge; it does not apply to any assignable object.(A 356)

Kant’s treatment counts this Achilles of dialectical inferences in the pure doctrine of the soul as based on a mistake, while also articulating features that make it deeply attractive. He concludes that the considerations raised by this argument do not support the claim that we can know that the thinking ‘I’ is simple.

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Kant treats the basic Achilles inference as a confusion of the simplicity of the representation ‘I’ in the ‘I think’, which represents the self as a mere something abstracted from any more detailed properties it might have, with the sort of simplicity of a simple substance that would be needed to make premise 1 true. He has several times cited close parallels between his critique of this inference to simplicity and his critique of the corresponding inference to the substantiality of the soul in the 1st paralogism. In his discussion of the 1st paralogism Kant explicitly emphasizes the contrast between the role of the ‘I’ in the ‘I think’ and the role of representations that refer to substances as public objects of experience. We shall see that this contrast helps reinforce his claim that the simplicity of the ‘I’ in the ‘I think’ does not count as knowledge that the self is a simple substance.

13.2 The First Paralogism We have seen that the significant parallel between the 2nd and the 1st paralogism suggested by N. K. Smith was stressed by Kant himself, at various points in his discussion of the 2nd paralogism. Let us now look at his criticism of the 1st paralogism. First Paralogism: Of Substantiality That, the representation of which is the absolute subject of our judgments and cannot therefore be employed as determination of another thing, is substance. I, as thinking being, am the absolute subject of all my possible judgments, and this representation of myself cannot be employed as predicate of any other thing. Therefore I, as thinking being (soul), am substance. (A 348)

Kant opens his critique of this first paralogism of pure psychology with a reminder of a fundamental point of his basic treatment of the category of substance, which he will argue undercuts any attempt to use this inference to establish anything nontrivial about the soul as thinking being. In the analytical part of the Transcendental Logic we have shown that the pure categories, and among them that of substance, have in themselves no objective meaning, save in so far as they rest upon an intuition, and are applied to the manifold of this intuition, as functions of synthetic unity. In the absence of this manifold they are merely functions of judgment without content. (A348–349)

Kant’s system affords a rich account of empirical realism, when these conditions of synthetic unity are met for objects of experience. Before saying any more about Kant’s conditions for empirical realism, let us explore further what he says about the attempt, in the absence of such conditions, to underwrite non-trivial objective content in the paralogism inference. Kant follows up his reminder by characterizing the use of ‘I’ in the paralogism as one which fails to satisfy these alluded to conditions for non-trivial objective content. I can say of any and every thing that it is substance, in the sense that I distinguish it from mere predicates and determinations of things. Now in all our thought the ‘I’ is the subject, in which

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thoughts inhere only as determinations; and this ‘I’ cannot be employed as the determination of another thing. Everyone must, therefore, necessarily regard himself as substance, and thought as [consisting] only [in] accidents of his being, determinations of his state. But what use am I to make of this concept of a substance? That I, as a thinking being, persist for myself, and do not in any natural manner either arise or perish, can by no means be deduced from it. Yet there is no other use to which I can put the concept of the substantiality of my thinking subject, and apart from such use I could very well dispense with it. (A349–350)

He points out that the resulting absence of non-trivial objective content makes any legitimate sense in which the I counts as a substance, unable to support any application to deduce persistence of the self or the immortality of the soul. Kant’s next paragraph expands further upon this absence of non-trivial content by contrasting it with the genuine non-trivial content that would be afforded by the sorts of application that would be supported by his account of empirical realism. So far from being able to deduce these properties merely from the pure category of substance, we must, on the contrary, take our start from the permanence of an object given in experience as permanent. For only to such an object can the concept of substance be applied in a manner that is empirically serviceable. (A349)

Kant here contrasts the empty use of substance in this paralogism with the nontrivial application to an object given in experience as permanent. Consider a house one stands before. A salient feature is the permanence that affords information to one who moves about it, to view it from different perspectives and otherwise further explore. For Kant the concept of substance can be applied in a manner which is empirically serviceable to publicly accessible objects located in three-dimensional space, which afford empirically accessible information to observers from different perspectives and locations.3 Kant’s passage continues by emphasizing his characterization of the contrastingly empty use of the concept of substance when restricted to the use of ‘I’ in the paralogism. In the above proposition, however, we have not taken as our basis any experience; the inference is merely from the concept of the relation which all thought has to the ‘I’ as common subject in which it inheres. Nor should we, in resting it upon experience, be able, by any sure observation, to demonstrate such permanence. The ‘I’ is indeed in all thoughts, but there is not in this representation the least trace of intuition, distinguishing the ‘I’ from other objects of intuition. Thus we can indeed perceive that this representation is invariably present in all thought, but not that it is an abiding and continuing intuition, wherein the thoughts, as being transitory, give place to one another.

3 See Harper 1992 and Harper 1996 for more on the role of space, with constraints on appearances as publicly accessible perceptible information about three dimensional shaped surfaces afforded to observers located at different perspectives and distances, in Kant’s empirical realism. Fundamental to Kant’s empirical realism is his attack on the Cartesian paradigm of knowledge as incorrigible access to contents of consciousness construed as merely subjective, so that not even Descartes’ demon could deceive one about them. Kant argues that this sort of restriction to merely subjective content cannot count as knowledge at all. To count as knowledge a proposition must be corrigible on the basis of publicly accessible information.

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It follows, therefore, that the first syllogism of transcendental psychology, when it puts forward the constant logical subject of thought as being knowledge of the real subject in which the thought inheres, is palming off upon us what is a mere pretence of new insight. We do not have, and cannot have, any knowledge whatsoever of any such subject. Consciousness is, indeed, that which alone makes all representations to be thoughts, and in it, therefore, as the transcendental subject, all our perceptions must be found; but beyond this logical meaning of the ‘I’, we have no knowledge of the subject in itself, which as substratum underlies this ‘I’, as it does all thoughts. (A 349–350)

There is, indeed, as N. K. Smith pointed out, a close parallel between Kant’s critique of the Achilles inference and these criticisms he gives of the 1st paralogism of substantiality. The contrast he makes, here in the 1st paralogism, with the non-trivial application of the concept substance to publicly accessible objects of experience reinforces his characterization of the ‘I’, as the representation found in all thought, as empty.4 Kant’s treatment of the 1st paralogism thus helps inform his central criticism of the Achilles inference. The simplicity of the representation ‘I’ in the ‘I think’ does not tell us that the self is a simple substance. Our discussion of the 1st paralogism affords, I hope, a little more insight into how Kant’s empirical realism informs his critique of the 2nd paralogism inference to the simplicity of the I as thinking being.

13.3 The Paralogisms in B Kant completely rewrote the paralogisms in the second edition (the B edition) of his Critique of Pure Reason. Instead of considering the four separate paralogism arguments he considered in the A version, in B he gave a general discussion which uses an argument for thinking being as substance as its central focus. For our purposes, the important thing to note is that none of these changes involve in any way giving up his negative assessment of the cogency of such arguments. Let us briefly review this treatment. Here is the presentation of the representative argument, together with Kant’s basic critique. The whole procedure of rational psychology is determined by a paralogism, which is exhibited in the following syllogism: That which cannot be thought of otherwise than as subject does not exist otherwise than as subject, and is therefore substance. A thinking being, considered merely as such, cannot be thought otherwise than as subject. Therefore it exists also only as subject, that is, as substance.

4

That the ‘I’ of the ‘I think’ is invariably present in all thought is the central assumption of Kant’s transcendental deduction of the application of the categories to objects of experience. See B129–169. Here in the 1st paralogism, Kant uses the contrast with non-trivial applications of substance to objects of outer sense to further emphasize that the simplicity of the representation of the self in the ‘I think’ does not count as an experience of the thinking subject as a simple substance.

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In the major premise we speak of a being that can be thought in general, in every relation, and therefore also as it may be given in intuition. But in the minor premise we speak of it only in so far as it regards itself, as subject, simply in relation to thought and the unity of consciousness, and not as likewise in relation to the intuition through which it is given as object to thought. Thus the conclusion is arrived at fallaciously, per sophisma figurae dictionis.a (B410–411; N. K. S., 371)

Here is Kant’s note a. a ‘Thought’ is taken in the two premisses in totally different senses: in the major premiss, as relating to an object in general and therefore to an object as it may be given in intuition; in the minor premise, only as it consists in relation to self-consciousness. In the latter sense, no object whatsoever is being thought; all that is being represented is simply the relation to self as subject (as the form of thought). In the former premiss we are speaking of things which cannot be thought otherwise than as subjects; but in the latter premiss we speak not of things but of thought (abstraction being made from all objects) in which the ‘I’ always serves as the subject of consciousness. The conclusion cannot, therefore, be, ‘I cannot exist otherwise than as subject’, but merely, ‘In thinking my existence, I cannot employ myself, save as subject of the judgment [therein involved]’. This is an identical proposition, and casts no light whatsoever upon the mode of my existence. (B411–412; N. K. S., 371)

Clearly, Kant is not taking back his earlier critique of this inference.5

5 In this case the new translation by Guyer and Wood is clearer than that of Kemp Smith. Here it is:

‘Thinking’ is taken in an entirely different signification in the two premises: in the major premise, as it applies to an object in general (hence as it may be given in intuition); but in the minor premise only as it subsists in relation to self-consciousness, where, therefore, no object is thought, but only the relation to oneself as subject (as the form of thinking) is represented. In the first premise, things are talked about that cannot be thought of other than as subjects; the second premise, however, talks not about things, but about thinking (in that one abstracts from every object), in which the I always serves as subject of consciousness; hence in the conclusion it cannot follow that I cannot exist otherwise than as subject, but rather only that in thinking my existence I can use myself only as the subject of judgment, which is an identical proposition, that discloses absolutely nothing about the manner of my existence. (Guyer and Wood, 448) Here is Kant’s German: Das Denken wird in beiden Prämissen in ganz verschiedener Bedeutung genommen: im Obersatze, wie es auf ein Objekt überhaupt (mithin wie es in der Anschauung gegeben verden mag) geht; im Untersatze aber nur, wie es in der Beziehung aufs Selbst-bewusstsein besteht, wobei also an gar kein Objekt gedacht wird, sondern nur die Beziehung auf Sich, als Subjekt, (als die Form des Denkens) vorgestellt wird. Im ersteren wird von Dingen geredet, die nicht anders als Subjekte gedacht werden können; im zweiten aber nicht von Dingen, sondern vom D e n k e n (indem man von allem Objekte abstrahiert), in welchem das Ich immer zum Subjekt des Bewusstseins dient; daher im Schlusssatze nicht folgen kann: ich kann nicht anders als Subjekt existieren, sondern nur: ich kann im Denken meiner Existenz mich nur Zum Subjekt des Urteils brauchen, welches ein identischer Satz ist, der Schlechterdings nichts über die Art meines Daseins eröffnet. (F. M. V., 390–392)

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We also have in this note more detail on why he counts it as a transcendental paralogism. Here is how Kant’s characterizes paralogisms: A logical paralogism is a syllogism which is fallacious in form, be its content what it may. A transcendental paralogism is one in which there is a transcendental ground, constraining us to draw a formally invalid conclusion. Such a fallacy is therefore grounded in the nature of human reason, and gives rise to an illusion which cannot be avoided, although it may, indeed, be rendered harmless. (A341–B399)

His note makes clear that the fallacy is an equivocation between the use of ‘thought’ in the first premiss and in the second premiss. In the first premiss, he tells us, the use of ‘thought’ is taken as relating to an object in general. On this use, thoughts could have as their objects things including those which can be given in intuition. In the second premiss, ‘thought’ is taken to relate only to the self as subject. This is, as he reminds us, the empty use of the ‘I’ as the mere subject of consciousness. This usage makes no commitment about whether or not it would require a substance to play this role in thought. Kant’s critique counts this inference to the self as substance as an invalid equivocation, of the same sort as he told us is involved in attempting to infer the simplicity of the self from the simplicity of the word ‘I’ used to refer to the subject of consciousness in the ‘I think’. In his next paragraph Kant offers a characterization of the heart of his critique of both arguments. He begins by pointing out the requirement that, to yield knowledge of an object to which it refers, an application of the term ‘substance’ must be made to rest on an intuition of something as permanent. If by the term ‘substance’ be meant an object which can be given, and if it is to yield knowledge, it must be made to rest on a permanent intuition, as being that through which alone the object of our concept can be given, and as being, therefore, the indispensable condition of the objective reality of the concept. (B412–413)

Having such a permanent intuition of its object is the indispensable condition of the objective reality of an application of the concept of substance. Kant goes on to characterize the role of the ‘I’ in inner intuition (as an expression of my consciousness of my own thought) as one where this required condition for an objective application of ‘substance’ is not available. Now in inner intuition there is nothing permanent, for the ‘I’ is merely the consciousness of my thought. So long, therefore, as we do not go beyond mere thinking, we are without the necessary condition for applying the concept of substance, that is, of a self-subsistent subject, to the self as a thinking being. And with the objective reality of the concept of substance, the allied concept of simplicity likewise vanishes; it is transformed into a merely logical qualitative unity of self-consciousness in thought in general, which has to be present whether the subject be composite or not. (B413)

Here, Kant vividly reminds us that the role of the ‘I’ in expressing the unity of self-consciousness required for thought is not an expression of knowledge that the thinking self is a single simple substance rather than a composite thing.

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13.4 Kant’s Discussion of the Second Step of the Achilles Inference In the first edition paragraphs 10–13 of his second paralogism, Kant carries out an experiment to test the usefulness of the proposition that the thinking ‘I’ is a simple substance. He argues that, even if this were granted, it could not be used to support the usual attempts to distinguish souls from material nature. These attempts to argue from the simplicity of the I to distinguish souls from material nature are what may be regarded as the second step of the Achilles inference. In paragraph 10, he identifies this second step as the only reason that the assertion that the soul is simple is taken as having value. Everyone must admit that the assertion of the simple nature of the soul is of value only in so far as I can thereby distinguish this subject from all matter, and so can exempt it from the dissolution to which matter is always liable. (A356)

Kant’s argues that, even if one were to grant the legitimacy of the basic Achilles inference, this second step would not follow. His case against the inference from the simplicity of the soul to distinguish the soul from material nature is based on his transcendental idealism. According to transcendental idealism our knowledge of the material world is limited to our knowledge of things as objects located in space and time, our epistemic framework for empirical knowledge of objects of experience. This sort of empirical knowledge does not tell us anything about how things might be in themselves, that is independently of these conditions we need to impose in order to have anything count as objective empirical knowledge for us. In paragraph 11, Kant cites his argument in the Transcendental Aesthetic as having proved that bodies are mere appearances of our outer sense and not thing in themselves. He also describes how the contrast between inner and outer sense contributes to the attractiveness of the argument to distinguish souls from bodies. In the Transcendental Aesthetic we have proved, beyond all question, that Bodies are mere appearances of our outer sense and not things in themselves. We are therefore justified in saying that our thinking subject is not corporeal: in other words, that, inasmuch as it is represented by us as object of inner sense, it cannot, in so far as it thinks, be an object of outer sense, that is, an appearance in space. This is equivalent to saying that thinking beings, as such, can never be found by us among outer appearances, and that their thoughts, consciousness, desires, etc., cannot be outwardly intuited. All these belong to inner sense. This argument does, in fact, seem to be so natural and so popular that even the commonest understanding appears to have always relied upon it, and thus already, from the earliest times, to have regarded souls as quite different entities from their bodies. (A357–358)

Whatever we may think about his transcendental idealism, Kant’s vivid discussion of role of the distinction between inner and outer sense is a very plausible account of the attractiveness of the second step of the Achilles inference. This suggests that the distinction between inner and outer sense contributes directly to the attractiveness of regarding souls as different from their bodies. In paragraph 12, Kant explains that his transcendental idealism would undercut this attractive inference to distinguish souls from their bodies.

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But although extension, impenetrability, cohesion, and motion–in short, everything which outer senses can give us – neither are nor contain thoughts, feeling, [preference or decision],6 these never being objects of outer intuition, nevertheless the something which underlies the outer appearances and which so affects our sense that it obtains the representations of space, matter, shape, etc., may yet, when viewed as noumenon ( or better, as transcendental object), be at the same time the subject of our thoughts. . . .(A358)

In paragraph 13 he further expands on how his transcendental idealism leaves open the possibility that bodies could be possessors of thoughts. I may further assume that the substance which in relation to our outer sense possesses extension is in itself the possessor of thoughts, and that these thoughts can by means of its own inner sense be consciously represented. In this way, what in one relation is entitled corporeal would in another relation be at the same time a thinking being, whose thoughts we cannot intuit, though we can indeed intuit their signs in the appearance. Accordingly, the very same being which, as outer appearance, is extended, is (in itself) internally a subject, and is not composite, but is simple and thinks. (A359–360)

Transcendental idealism would allow the identification of persons as bodies which think, even if the basic Achilles inference to count the thinking I is a simple substance were sound. The failure of the basic Achilles inference does allow the common identification of persons as bodies which think, whether or not Kant’s transcendental idealism is viable.

6

I have used [preference or decision] to translate [Neigung oder Entschliessung] (See F. M. V., 386). Kemp Smith gives these as [desire or resolution] (N. K. S., 339), while Guyer and Wood give them as [inclinations or decisions] (Guyer and Wood, 420).

Chapter 14

William James and the Achilles Argument Hunter Brown

The Achilles argument, as it is understood in this paper, is an inference from the unity of conscious perceptual and intellectual experience to an immaterial simple soul. William James was aware of the argument. In his response, he rejected the specific metaphysics of soul proposed by it, but retained the idea of soul as a placeholder in Philosophy for a phenomenon that is not yet understood.

14.1 The centerpiece of the Achilles argument is the unity of experience, for it is from such unity that the argument draws its inference regarding the simplicity and immateriality of the soul. The argument is a reductio which attempts to eliminate one of what are purportedly only two possible explanations of such unity – a complex material entity or a simple immaterial one. The material alternative is rejected on the grounds that a multipart entity could not account for the simple unity of experience. James uses an example, in this connection, which is reminiscent of similar such examples found in the history of the argument. ‘Take a sentence of a dozen words, and take 12 men and tell to each one word. Then stand the men in a row or jam them in a bunch, and let each think of his word as intently as he wills; nowhere will there be a consciousness of the whole sentence.’1 Since the unity of experience plays such a central role in the Achilles it is important to ensure that conscious life does in fact involve just the sort of unity asserted by the argument. Ensuring this, however, is difficult because it requires experience to become an object for itself. That is to say, actual experience, in its immediate occurrence, must be made into an object of another experience which is reflective

H. Brown Department of Philosophy, King’s University College, The University of Western Ontario, 266 Epworth Avenue, London, Ontario, Canada N6A 2M3 Phone: (519) 433-3491, ext. 4555, Fax: (519) 433-0353 e-mail: [email protected] 1 William James, The Principles of Psychology, vol. 1 (New York: Dover Publications, 1890), 160.

T.M. Lennon, R.J. Stainton (eds.), The Achilles of Rationalist Psychology,  C Springer Science+Business Media B.V. 2008

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and analytic in character. The latter reflective form of experience, however, requires that its objects be stabilized for the purposes of extended examination. Not all the constituents of experience in its immediate occurrence, however, on James’s account at any rate, lend themselves particularly well to such stabilization. This is especially the case with the fluid relations that James takes to be constitutive of experience in its immediacy. He puts it this way: It is very difficult, introspectively, to see the transitive parts for what they really are. If they are but flights to a conclusion, stopping them to look at them before the conclusion is reached is really annihilating them. Whilst if we wait for the conclusion to be reached, it so exceeds them in vigor and stability that it quite eclipses and swallows them up in its glare. Let anyone try to cut a thought across in the middle and get a look at its section, and he will see how difficult the introspective observation of the transitive tracts is. The rush of the thought is so headlong that it almost always brings us up at the conclusion before we can arrest it. Or if our purpose is nimble enough and we do arrest it, it ceases forthwith to be itself. As a snowflake crystal caught in the warm hand is no longer a crystal but a drop, so, instead of catching a feeling of relation moving to its term, we find we have caught some substantive thing, usually the last word we were pronouncing, statically taken, and with its function, tendency, and particular meaning in the sentence quite evaporated. The attempt at introspective analysis in these cases is in fact like seizing a spinning top to catch its motion, or trying to turn up the gas quickly enough to see how the darkness looks. And the challenge to produce these psychoses which is sure to be thrown by doubting psychologists at anyone who contends for their existence, is as unfair as Zeno’s treatment of the advocates of motion, when, asking them to point out in what place an arrow is when it moves, he argues the falsity of their thesis from their inability to make to so preposterous a question an immediate reply. The results of this introspective difficulty are baleful. If to hold fast and observe the transitive parts of thought’s stream be so hard, then the great blunder to which all schools are liable must be the failure to register them, and the undue emphasizing of the more substantive parts of the stream.2

On a Jamesean view, then, the predominance of reflective analysis in the discipline of Philosophy has given rise, historically, to a pattern of inattention to the basic unity of experience provided by such relations, and has given rise as well, therefore, to a pattern of thinking about experience as consisting, from the outset, of a cluster of distinct parts. These propensities have in turn led to an amplification of the question about how such parts could subsequently come to be unified. In answer to this question theories of aggregation have come to occupy an important place in Philosophy. Approaching the Achilles along such well-worn paths, one might well be inclined to assess the argument in terms of whether or not soul would be an appropriate agent of aggregating an original diversity. The problem with such an approach, as James sees it, is that it fails to take adequately into account a feature of all aggregates with which we are actually familiar, namely, that the unity to which they give rise is the result of the ‘EFFECTS, wrought by the units said to be “combined,” UPON SOME ENTITY OTHER THAN THEMSELVES. Without this feature of a medium or vehicle, the notion of combination has no sense.’3 It is this contention, James thought, that ‘spiritualist’ believers in soul had long used to support their 2 3

Ibid., 243–244. Ibid., 158. James singles out Lotze as having ‘set forth the truth of this law more clearly and

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persistence in holding that the unity of the diverse constituents of conscious life must be explained in terms of how such constituents ‘affect a third entity, the soul. This has the compounded idea, if you please so to call it; and the compounded idea is an altogether new psychic fact to which the separate ideas stand in the relation, not of constituents, but of occasions of production.’4 James’s point here is that the sort of experience which is of interest to the Achilles argument may appear, when one reflects upon the contribution of various influences to its emergence, to be explicable entirely in terms of an aggregation of such influences. Even in the aggregated state, however, James points out, each such influence ‘remains, in the sum, what it always was’5 – as in the aforementioned example of individuals each knowing one word of a sentence. What requires explanation in the case of the Achilles is witnessed aggregates, and it is these which James says requires the identification of a medium or vehicle capable of such witnessing. The propensity of the Achilles to identify the witnessing capacity with soul is closely related to the purported unity of the witnessing experience, an experience which Hume describes, in his portrayal of the Achilles, as ‘a being altogether inseparable and indivisible.’6 Whether the medium or vehicle on behalf of which James argues should be identified with soul, however, has much to do with whether, in fact, the unity of consciousness actually is ‘altogether inseparable and indivisible.’ Notwithstanding his wariness of introspection, he does tackle at length this question about the nature of the unity of experience in its immediacy, and whether such experience is in fact ‘altogether inseparable and indivisible.’ The result of James’s efforts in this respect is a position which, while emphasizing the primordial unity of experience – because this is what he found reflective analysis among his contemporaries had most often missed – does not depict such experience to be an absolute unity. The simplest bits of immediate experience are their own others . . . The concrete pulses of experience appear pent in by no such definite limits as our conceptual substitutes for them are confined by. They run into one another continuously and seem to interpenetrate. What in them is relation and what is matter related is hard to discern. You feel no one of them as inwardly simple, and no two as wholly without confluence where they touch. There is no datum so small as not to show this mystery, if mystery it be. The tiniest feeling that we can possibly have comes with an earlier part and a later part with a sense of their continuous procession. . . . The gist of the matter is always the same – something ever goes indissolubly with something else. You cannot separate the same from its other except by abandoning the real altogether . . . What is immediately given in a single and particular instance is always something pooled and mutual.7

copiously than any other writer’ (Ibid., 159). He refers his readers to Lotze’s Microcosmos bk. II. ch. I. § 5; Metaphysik, §§ 242, 260, and Outlines of Metaphysics, part II. ch. I. §§ 3, 4, 5. 4 Ibid., 161. 5 Ibid., 158–159. 6 David Hume, A Treatise of Human Nature, ed. David Norton and Mary Norton (Oxford: Oxford University Press), 154. 7 William James, Essays in Radical Empiricism and a Pluralistic Universe (New York: Longmans, Green and Co., 1943), 282–284.

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James attempts to illustrate this point on a number of occasions in his corpus, one of which uses the example of experiencing a thunderstorm. Such an experience seems, upon reflection, to be a sequence of individual states involving, for example, alternating periods of silence and crashing noises. In the actual experience of the storm, however, such distinctive states turn out to be interrelated in a way better described as ‘thunder-breaking-upon-silence-and-contrasting-with-it.’8 The constituent elements of such experience are not as distinct as they may, upon reflection, at first appear to be. ‘Into the awareness of the thunder itself the awareness of the previous silence creeps and continues; for what we hear when the thunder crashes is not thunder pure.’9 The impression of the loudness of the thunder, rather, is closely related to the silence which precedes it, and the impression of the silence is no less closely related to the magnitude of the noise which punctuates it. What is true in this case is true more generally, according to James: ‘It would be difficult to find in the actual concrete consciousness of man a feeling so limited to the present as not to have an inkling of anything that went before.’10 Hence, he concludes, the parts of immediate experience are not as separable from one another as is often supposed, upon reflection, although they do not entirely lose their individuality on that account. Experience in its immediacy is constituted by its individual elements and by the relations on account of which each such element ‘goes indissolubly with something else.’ It is constituted, in other words, by both a plurality of distinctive relata, as well as a unity among them. The italicizations in James’s conclusion are significant here: ‘The great point is to notice that the oneness and the manyness are absolutely coordinate. Neither is primordial or more essential or excellent than the other.’11 If, for the sake of argument, one gives James the benefit of the doubt in this assessment of experience, the problem which emerges is not just how to account for a pure unity, nor for an aggregate of entirely distinct parts, for experience is neither a unity free of all plurality nor a plurality free of all unification. Experience, rather, is a unified-plurality. To the extent that such a unified-plurality seems to involve a true unity, rather than just an aggregation, it does provide some grounds for inference to a simple soul which would be capable of supporting such a unity. To the extent, however, that experience also involves a diversity that is inseparable from such unity, the Achilles would be unable to eliminate a complex material medium by way of a reductio. This problem is amplified, in James’s work, by the fact that such plurality sometimes occurs in an especially disintegrative state illustrated richly in the many examples of clinical pathology provided in the Principles of Psychology. An immaterial simple soul would be no more capable of supporting such a plurality than would a complex material entity be capable, as the Achilles claims, of supporting a pure unity. In the end, then, the problem of experience, on James’s account, is not

8

James, Principles, 240. Ibid. 10 Ibid., 241. 11 William James, Pragmatism (Cambridge, Mass.: Harvard University Press, 1975), 68. 9

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a problem of its unity or of its oneness but, to borrow a famous phrase from the history of philosophy, it is the problem of ‘the one and the many.’ In summary up to this point, the centerpiece of the Achilles argument’s justification of simplicity and immateriality of soul as a vehicle or medium of experience is its presumption that experience can be treated as an unadulterated simple unity. Taking into account the difficulty of reflectively grasping the nature of experience in its immediacy, it appears to James, at any rate, that immediate experience is neither a pure aboriginal unity, lacking all internal distinction, nor an aboriginal plurality requiring subsequent transformation into a pure unity. It is, rather, a true unity which nonetheless involves a real plurality, and in some pathological cases a troublingly prominent one. The basic experiential datum from which inference is to be drawn in grappling with the Achilles argument, then, is more complex than the pure unadulterated unity required by that argument. If multiplicity is in fact an integral part of the unity of experience, then such multiplicity would undermine inference to an immaterial simple soul, for such soul would be no better able to accommodate plurality than would a complex physical substance be able, as the Achilles contends, to accommodate pure unity.

14.2 Hume, Kant, and many others were impressed by the perennial resilience of the Achilles argument. One wonders whether perhaps there may be some other aspect of experience, beyond what has so far been considered, which might account for such resilience. James’s work has something to say on this subject that may be of value. Alongside unity-in-plurality there is an additional characteristic of experience which is easily overlooked or misinterpreted, according to James. While each present state of consciousness is distinguishable from the states that have preceded it, the union between the present state, and the states prior to it, is not just one of simple addition or aggregation. That relationship, rather, reveals itself to be one best described in terms of ‘appropriation’.12 That is to say, each present state of consciousness seems not just to be added to former states but, rather, each present state seems to appropriate the state prior to it and, through this appropriation, to appropriate also, along with that state, everything which the prior state itself had previously appropriated from the states preceding it. This appropriation process, moreover, James contends, involves a peculiar possessive element. Each present conscious state seems not only to be united with past states through an appropriative process, but seems also to experience those prior states as ‘its own.’13 I do not wake up from sleep, for example, and simply

12 13

James, Principles, 401. Ibid.

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recognize an aggregation of past conscious states from the previous night and the days preceding it. In the awareness of those past states, rather, there is the sense, in connection with each such state, that ‘thou art mine, and part of the same self with me.’14 Each present state of consciousness, in other words, ‘is thus born an owner, and dies owned, transmitting whatever it realized as its Self to its own later proprietor.’15 While this process involves aggregation, it involves more than mere aggregation. As successive states are added, in experience, one finds that the individual will ‘emphasize and care paramountly for certain . . . [such states] as ‘me,’ and appropriate, to these, the rest . . . Whatever remembered-past-feelings resemble this present feeling are deemed to belong to the same me with it.’16 Terence Penelhum, I believe, was driving at the same thing when, in response to Hume’s theory of selfhood and memory, he once observed that an integral part of . . . [the experience of a person who remembers a past event] is not only that some action was done, some experience had, or some event witnessed, but that it was done or had or witnessed by him. In other words, to say that he remembers . . . is not just to say that he now has some mental image or conviction, even though it is likely to include this; it is to say that the past action, experience, or event referred to, is part of his own past. But it now becomes clear that we cannot even state the memory criterion of identity without having some prior (and therefore independent) notion of the identity of the person. So the identity of the person must in the end rest upon some other condition, and the claim that it could rest solely upon memory must be false.17

For Penelhum, as for James, theories of aggregation, whether through memory or some other mechanism, may have merit, but they ‘presuppose that we understand what it is for the rememberer to be identical with the person who did those deeds or had those experiences. And we do not actually understand this.’18 It is, James would say, in concert with Penelhum, a ‘common philosophic blunder’19 to argue that the foregoing personal and possessive character of experience arises through a process of retrospective personification, for we are unable to find any stage, however primitive, at which experience is truly impersonal, much less a stage at which such impersonal experience is made personal. All conscious states, rather, are found ‘already personified.’20 It is somewhat, says James, like a rancher recognizing cattle upon which he has placed his brand. The cattle do not belong to the rancher because they are branded. They are branded because they already belong to the rancher.21 I do not make impersonal experiences mine by designating them as mine after having had them. I designate them as mine because that is how I found them in the first place. The unity of experience, on this view, then, ‘is not a mere appearance of 14 15 16 17 18 19 20 21

Ibid., 339. Ibid. Ibid., 400. Terence Penelhum, Religion and Rationality (New York: Random House, 1971), 351. Ibid., 353. James, Principles, 226. Ibid., 227. Ibid., 337.

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similarity or continuity, ascertained after the fact. . . . It involves a real belonging to a real Owner, to a pure spiritual entity of some kind. Relation to this entity is what makes the self’s constituents stick together as they do for thought.’22 On James’s account, then, ‘the elementary psychic fact’ is that experience involves ‘not thought or this thought or that thought, but my thought, every thought being owned.’23 It ought not to be surprising, then, he adds, when Hume reports that, notwithstanding introspective diligence, he has found no single unified self within, and so will proceed to explore possible processes of aggregation. The persistence of belief in a single unified self, James responds, notwithstanding how widely Hume’s experience is replicated by others, is rooted in the fact that the foregoing sense of possessiveness can only be ‘felt’,24 not grasped as an object – and felt, moreover, as something which is ‘no mere summation.’25 For all its elusiveness, however, it remains remarkably persistent. If we once again give James benefit of the doubt, this time regarding the appropriative and personal character of conscious experience, then perhaps one could conjecture that it is the persistent unity involved at this level of experience to which the Achilles looks, and which contributes significantly to the perennial resilience of that argument. Even if this is true, however, James would argue, the Achilles still goes too far in its inference from such a center of personal unity to a simple immaterial soul. The state of present consciousness, as portrayed above, ‘can be fully described without supposing any other agent than a succession of perishing thoughts, endowed with the functions of appropriation and rejection, and of which some can know and appropriate or reject objects already known, appropriated, or rejected by the rest.’26 As far as we can tell, introspectively, it is the present state of consciousness alone which is ‘the actual focus of accretion, the hook from which the chain of past selves dangles, planted firmly in the present . . . Anon the hook itself will drop into the past with all it carries, and then be treated as an object and appropriated by a new Thought.’27 That new state of consciousness ‘seems to be the Thinker; and though there may be another non-phenomenal Thinker behind that, so far we do not seem to need him to express the facts.’28 The most accurate expression of the facts, then, is this, on a Jamesean view: ‘My present Thought stands in the plenitude of ownership of the train of my past selves . . . the most real owner there can be, and all without the supposition of any “inexplicable tie,” but in a perfectly verifiable and phenomenal way.’29

22 23 24 25 26 27 28 29

Ibid. Ibid., 226. Ibid., 298. Ibid., 299. Ibid., 342. Ibid., 340–341 Ibid., 342. Ibid., 360.

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James cautions that this expression of what he takes to be the facts is, however, only the best description he can find for the phenomenon. It is not an explanation.30 A fully adequate explanation for what has been so described remains to be found. Such explanatory shortfall cannot be satisfactorily resolved, however, by postulating a spiritual entity such as soul, for that entity would be devoid of meaning in this context. What, after all, would such a position amount to? One could say only that soul is an unknown entity responsible, in some unknown way, for activities which can all be clearly traced back to conscious states themselves. Such a hypothetical soul would be an empty concept, in other words, a problem that James found with Kant’s Transcendental Unity of Apperception. Nonetheless, James goes on, ‘a phenomenon would not itself be . . . unless there were something more than the phenomenon.’31 The failure of both materialist and immaterialist positions to account fully for the personal, unified-plurality of experience leaves a gap in philosophy, a gap that needs to be protected lest it be forgotten or ignored – or responded to unsatisfactorily, as has been the case, James thought, with theories of aggregation. A placeholder is needed, in other words, and it is to soul that James assigns this role, giving to soul the function of expressing ‘one’s protest against the notion that the bare existence of the phenomena is the total truth.’32 One might well find the choice of soul here to be a peculiar one, given the degree to which the concept of soul has become, throughout the history of philosophy and theology, encumbered with so much dubious metaphysical baggage. Beneath such speculative baggage, however, James the pragmatist proposes, the concept of soul may well have derived its real, practical, enduring vitality from its success in performing a much more basic philosophical function. What positive meaning has the Soul, when scrutinized, but the ground of possibility of the thought? . . . And what is this after all but giving a sort of concreted form to one’s belief that the coming of the thought, when the brain-processes occur, has some sort of ground in the nature of things? If the word Soul be understood merely to express that claim, it is a good word to use. But if it is used to do more . . . then it is an illusory term. It is, in fact, with the word Soul as with the word Substance in general.33

Historically, James judges, there is usually an experiential basis of some kind, however elusive, for concepts which exhibit such perennial vitality, and so they should not be abandoned lightly. ‘One cannot afford to despise any of these great traditional objects of belief. Whether we realize it or not, there is always a great drift of reasons, positive and negative, towing us in their direction.’34

30

Ibid., 354. Ibid., 346. 32 Ibid. 33 Ibid., 345–346. 34 Ibid., 181. 31

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14.3 Overall, a Jamesean response to the Achilles argument exhibits his trademark propensity to straddle both rationalist and empiricist traditions. A close scrutiny of actual experience, he would say, in so far as that is possible, pushes inquiry beyond the limits of a satisfactory empirical, materialist solution to the problem of the unity of experience. He argues that the same experiential data which pushes one beyond empirical solutions, however, does not provide enough to develop a clear metaphysic. The concept of soul may be used to represent an explanatory ‘more,’ under such conditions, but cannot be given a clear metaphysical definition. Such a position straddles not only rationalist and empiricist traditions but also two stages of the historical trajectory of modern thought, as such thought moves away from a metaphysic of soul toward more functional analyses. James’s hybrid position, involving both metaphysical and functional elements, may turn out to be significant only in purely historical terms as an example of transitional, late 19thcentury thought. Perhaps, however, it might turn out in the end to have been of greater contemporary service than this in its efforts to resist the complete abandonment of soul-language, at least as a placeholder. Whatever the case in these respects, James, while certainly not embracing the Achilles argument, does propose a position which has a peculiar kinship with the spirit, at least, of that argument.

Chapter 15

The Binding Problem: Achilles in the 21st Century Christopher Viger, Robyn Bluhm and Sharday Mosurinjohn

15.1 Introduction How any distributed patterns of activity, whether they are among hundreds or millions of neurons, can lead to unitary percepts or singular actions remains a mystery. Binding the activity evoked by particular objects does not solve this problem and does little to reduce its scope (Ghose and Maunsell 1999, 83–4).

Recall from the introduction to this volume how Lennon and Stainton present the Narrow Achilles argument as a simple two-premise argument. P1: Unification of representations takes place. P2: Only a simple, unified substance can unify representations. Therefore, C1: The human soul or mind is a simple unified substance.

With the caveat that the human soul or mind is whatever unifies our mental representations—which we can simply stipulate—the argument is valid, hence the only way to resist the conclusion is to deny at least one of the premises. The long history of the argument recounted in the other papers in this volume demonstrates how resilient these premises are, however. P1 is compelling because it captures our phenomenology; that just is how things seem to us. The force of P2 is reflected in the quote beginning our paper from contemporary neuroscientists who cannot conceive of an alternative to it. Save for the reference to neurons, this quote could have come from any era. Yet P2 flatly contradicts our contemporary materialist-cumneuroscientific worldview, so an alternative is wanting. Do the cognitive sciences have something to add by way of refuting the Achilles?

C. Viger Department of Philosophy, Talbot College, The University of Western Ontario, London, Ontario, Canada N6A 3K7 Phone: (519) 661-2111, ext. 85755, Fax: (519) 661-3922 e-mail: [email protected]

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The most direct means of attacking the Achilles is to deny P1. ‘Many scientists and philosophers, applying Occam’s Razor, . . . [dismiss] the seeming unity of consciousness as illusory or epiphenomenal’ (Newman and Grace 1999, 209). For example, Daniel Dennett (1991) argues that the only unification that occurs is unification of properties in the world. There is no Cartesian Theater, no place where it all comes together in our heads. This position obviates the need for an alternative to P2; since the unity of representations never arises, we never face the issue of the nature of the unifier. However, this view is faced with the challenge of explaining why our experiences seem to be unified. Is the seeming itself a representation (Brook, in Ross 2000)? And isn’t that unified? (We return to this issue in Section 15.6 below.) The more common line of research in cognitive science relevant to the Achilles—dubbed ‘the binding problem’ by Anne Treisman—is to try to explain P1 without appeal to a simple substance. Its relation to Achilles arguments is quite direct. If cognitive scientists can demonstrate how representations are unified without appealing to a simple, unified substance, P2 will be shown to be false and the conclusion of the Achilles is resisted. Since broad Achilles arguments depend on the narrow one, they are equally refuted. In this paper, we survey attempts in neuroscience and psychology to solve the binding problem. It is important to keep in mind that cognitive scientists are not explicitly attempting to respond to the Achilles argument. Their results bear directly on P1 only, and the sense of binding they have in mind does not directly correspond with the phenomenological unity of representations in experience to which P1 refers. To help situate our survey of neuroscience and psychology, in Section 15.2 we present an overview of the binding problem. In Sections 15.3 and 15.4 we review the methods used and proposals made for solving the binding problem in neuroscience and psychology, respectively. We conclude each section with a brief summary relating the results back to P1. In the interests of not falsely elevating expectations, it should be noted here that there is no accepted solution to the binding problem in either neuroscientific or psychological terms and that for reasons we discuss, the prospects of any of the proposals reviewed being developed into a solution are not bright. However, in Section 15.5 we propose a way of combining the results we have surveyed that improves the prospects of finding a solution as to how some binding, scientifically understood, might occur. Interestingly, our proposal explicitly returns us to the issues in the Achilles by raising the question of what (or better who) the proposed binding mechanisms are binding representations for. Thus, in the penultimate section we return to the Achilles proper. We note that conceptually the cognitive sciences are presenting a representational solution to binding that is quite compatible with Kant’s own offered solution to the Achilles. Based on the cognitive scientific accounts of binding we provide a biological motivation for Kant’s logically constructed subject, in virtue of which we experience a unified subject experiencing unified representations. Based on the results of our investigation, we conclude by suggesting the role that cognitive science can play in fully responding to the Achilles argument.

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15.2 What is the Binding Problem? Perhaps the most intuitive way in which the binding problem arises is that we experience a single object through different sensory modalities. For example, the taste, smell, and warmth of a cup of coffee, the sound of the coffee being poured, the sight of the cup, and the feeling of it in one’s hands are all experienced as properties of the same cup of coffee, despite being processed by different senses, hence different parts of the brain. Less intuitively, it seems that even within a single modality binding occurs. For example, color, shape, and motion are processed in specialized areas of the visual cortex, yet we experience objects as having all of these properties together; i.e. we experience the properties as bound to the same object (property binding). Furthermore, color itself results from differential responses in three populations of cells, called cones. The combined activity of the different systems determines the color experienced, and the possible combinations determine the full range of color experience (Kandel et al. 1995); combinations entail some sort of binding (range binding). So the binding problem may actually be many problems. Indeed, Treisman (1996) lists seven distinct problems, some focusing on what gets bound, such as properties or parts of objects, others, focusing more on mechanisms of binding, such as how binding occurs over time or how binding can be conditional on what else is bound. Treisman notes that we must be open to the possibility that distinct types of binding might result from different mechanisms; there may not be a single solution to the binding problem. In addressing the various issues that go under the heading of the binding problem, researchers have concentrated on how sensory systems work, particularly vision. Research has proceeded in two directions. Neuroscientists investigate neuronal activity and neural architecture in an attempt to determine the neural mechanisms of binding. Psychologists, on the other hand, study behavior in an attempt to functionally characterize the performance of particular sensory systems. Ideally, functionally characterized sensory binding operations will decompose into relatively simple procedures that can be neurally implemented.1 In the following two sections, we briefly present the methodologies used in neuroscience and psychology in investigating the binding problem, and review more fully the theoretical solutions they motivate. Our survey is not intended to be exhaustive, but rather representative of the kinds of proposals coming from cognitive science that are relevant to the philosophical issues raised in the Achilles.

1

This methodology results from adopting the tri-level hypothesis toward information processing. The processes can be analyzed at a semantic or computational level, a syntactic or algorithmic level, and a physical or implementational level. Though the methodology can only be successful if P2 is false, using it is not to beg the question against P2 because it underpins empirical investigation not conceptual argumentation. A full exposition of the tri-level hypothesis is given in Dawson (1998).

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15.3 Neuroscience and Binding 15.3.1 Neuroscientific Methodology In the neurosciences, experimental work on the binding problem is done in the area of electrophysiology. One method for investigating the electrical activity in the brain is to insert electrodes into a small number of neurons in various areas of interest, then to measure the timing and frequency of the action potentials—the electrical discharge through a neuron’s axon, colloquially referred to as firing—of each neuron compared with the timing and frequency of firing of the other measured neurons. The information from a single cell, a single-unit recording, reveals how, and to what, a single neuron responds. The cumulative information taken from several cells during the same time period, multi-unit recordings, give information about quite small populations of neurons. However, because this procedure is invasive it cannot normally be performed on humans. Another method used with animals measures electrical activity in the brain using electrodes that rest directly on the surface of the brain. This method measures the activity of a population of neurons and is similar to, though more accurately localized than, human studies using electroencephalography (EEG) techniques, which measure changes in electrical potential on the scalp, rather than on the brain itself. Both techniques reflect fluctuations in the electrical activity of the population of brain cells beneath the electrode.

15.3.2 Neuroscientific Proposals for Solving the Binding Problem Results obtained using the techniques described above, have led theorists to posit solutions to binding that fall in two main classes: structural and operational. A succinct way of capturing the differing intuitions in these two classes of solutions is that, while both agree that some kind of localization is required to unify representations, structuralists opt for spatial localization, whereas operationalists take localization to be temporal. One important finding from single-unit recordings is that there are neurons that respond to a quite specific stimulus. This has led to the conjecture that there are cells whose function is to signal the presence of particular objects in the environment. This ‘classical’ solution to the binding problem actually accepts the intuitions underlying P2 in the Achilles. A single neuron firing, signals the presence of some object. While a single neuron is not quite a simple substance, it does offer the sort of unity that is supposed necessary for binding representations into a whole. Those rejecting the intuition underlying the Achilles note that there is significant synchronous firing among populations of neurons. On this view, binding results from the coordinated activity of many neurons. Binding is a result of how the system operates, not just how it is built. Of course, hybrid models are also possible, as we will see below. We now look at each proposal in turn. Structural solutions are hierarchical, with information being fed forward from sensory areas to areas of higher cognition through distinct levels. Lower-level

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regions process specific features of an object, such as the three systems of cone cells mentioned above, for processing components of color. Lower levels project the results of their computations to higher-level regions, which respond only (or at least most strongly) to specific combinations of features processed at the lower levels, for example, to attributes of objects, such as specific shapes or colors. At the highest levels of processing are neurons that respond to particular combinations of attributes that constitute objects; reference is often made to a ‘grandmother cell,’ a hypothetical ‘neuron that would respond only to a specific, complex, and meaningful stimulus, that is, to a single percept or even a single concept’ (Gross 2002, 512). The neural architecture suggested by the hierarchical view is meant to be a kind of pyramid, with fewer cells at higher levels, narrowing to the single grandmother cell. The difficulty with this view, as first raised by von der Malsburg (1981), is that the pyramid would actually have to be inverted. Higher levels of processing would require cells that could be activated by each combination of active cells at the lower level. But the number of combinations of cells is exponentially larger than the number of cells. Starting even with a moderate number of cells at the lowest level, would require more cells than are known to be in the brain, with only a few levels of processing.2 Von der Malsburg (1981) is generally credited with being the first to propose temporal binding as an alternative to the hierarchical solution. Temporal binding suggests that synchronous activation of lower-level neurons is sufficient to bind the features of an object together so that higher-level regions and grandmother cells are not required. Von der Malsburg pointed out that by representing objects in assemblies of lower-level cells, we avoid the problem of combinatorial explosion, since the view does not require neurons corresponding to each combination of lower-level cells; combinations of synchronous activity constitute bound representations. Moreover, because different objects share some of the same features, cells may be parts of different assemblies at different times. For example, cells that process ‘red’ may be members of a cell assembly that represents a red apple, and later may be members of a cell assembly that represents a red Lamborghini. Thus, even at the lower level, the number of neurons required is neurologically plausible. A great deal of animal research using the methods described above—multiunit recordings and electrodes placed on the brain—provides empirical evidence that neurons involved in the perception of the same object fire (more-or-less) synchronously (reviewed in Engel and Singer, 2001). The majority of this work is concerned with visual binding, though some studies measure activity in olfactory,

2 Assuming simply that a cell can be active or not, a level with n cells has 2nd combinations of active cells. It is, however, possible that for a few very familiar objects there could be a single neuron that responds to the presence of an object. For example, recent work on an epileptic patient uncovered a neuron in the anterior hippocampus that ‘was selectively activated by pictures of the actress Halle Berry as well as by a drawing of her . . . This unit was also activated by several pictures of Halle Berry dressed as Catwoman, her character in a recent film, but not by other images of Catwoman that were not her . . . Notably, the unit was selectively activated by the letter string “Halle Berry” ’ (Quian Quiroga et al., 2005, 1104).

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auditory, somatosensory, or motor cortices in response to an appropriate stimulus. From multi-unit recordings it is possible to determine the exact timing of the firing of a small number of individual neurons and correlate them. More often, however, synchrony is measured by monitoring the dynamics of activation for populations. Because these population-level measurements reflect the activity of a number of neurons, they are often described in terms of sinusoidal patterns of regular activity called oscillations. The ‘peak’ of each oscillation represents a small window of time, e.g. 5 ms, at which a large number of the neurons in the population are firing; the ‘valley’ represents a time at which fewer neurons are firing. The oscillations tend to occur in a particular frequency range, the gamma band, which spans approximately 25–80 Hz. In particular, oscillations at 40 Hz have been associated with temporal binding and have been suggested by some authors (particularly Crick and Koch, 1990) to be the frequency that reflects consciousness. However, it should be noted that much of this work takes place in animals that have been anesthetized, which should caution against the assumption that temporal binding is an indication that the object is being consciously perceived. At best, binding oscillations at 40 Hz is a necessary part of conscious perception, but it is not sufficient. Von der Malsburg’s account is that binding just is synchronous activation in lower-level processes. It might fairly be wondered, however, just what synchronous oscillations contribute to binding. After all, healthy neurons are constantly firing, meaning that for any time window we might consider, there is significant synchronous activity in the brain; yet, this activity does not constitute binding. One way to address this worry is to recall that synchronous activation is a populationlevel effect. The point is not just that many neurons fire together; it is that many more neurons fire together at some times than at others. The peaks of activity can cause further processing by meeting a threshold of activation for other neurons. It is the neurons that are working together that determine further processing. For example, Newman and Grace (1999) propose synchronous oscillations in the lower EEG range, below 8 Hz, as a gating mechanism, selectively allowing only certain signals to pass between the cortex and sub-cortical systems, such as the thalamus, which is a relay for sensory information, and the amygdala, which processes emotions. Interestingly, the hippocampus, which converts working memories into long-term memories, controls this gating function. So it may be that the patterns of neural activation that get processed during object recognition are those matching patterns already learned. The default for the brain then could be to treat information passing through the gates as information about the same object.3 (We return to this idea in Section 15.5 below.) Damasio (1989) has a different, though not incompatible, explanation for what synchronous oscillations contribute to binding. He develops his account by exposing

3

It is worth noting that information is thought to be encoded exclusively in the firing rate of a neuron (or perhaps an initial pulse in a sequence). Synchronous firings merely contribute to what information is processed.

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several weaknesses in the hierarchical account beyond computational intractability. If the hierarchical account is correct, then there should be some area of the brain where the highest-level neurons representing objects reside, the place where all lower-level processing converges. Based on the known architecture for sensory processing, the most likely areas would be anterior regions of the temporal and prefrontal cortices. Thus, we would expect that lesions to these areas would impair binding, but, in fact, patients with bilateral damage to either of these regions do not appear to have perceptual or memory problems that would indicate a failure of binding. Damasio finds no area that could ‘function as a fully encompassing and single convergence region’ (Damasio 1989, 35–36). What he does find is that damage to modal association cortices, such as visual association cortex, can disrupt recognition and recall for that modality, without affecting perception in that modality, or recall and recognition in other modalities (Damasio 1989, 34). This leads him to posit an alternative to the hierarchical view that is a hybrid between traditional hierarchical binding and temporal binding. Like von der Malsburg, Damasio thinks that synchronous lower-level activation is central in binding, but on Damasio’s view the activation is much more widespread, spanning distinct sensory modalities. In addition, Damasio thinks that this widespread lower-level activity is coordinated from higher-level regions, called convergence zones. A convergence zone is superficially similar to a grandmother cell in that lower-level activity feeds into it in a many-to-one fashion. It is importantly different, however. To begin with, a convergence zone is not a neural encoding of anything in the way a grandmother cell is supposed to be. A convergence zone simply encodes information about other neural activity without reproducing the representational content of lower-level processing. Secondly, a convergence zone is not a neuron to which others converge, like a grandmother cell; it is defined by a synaptic pattern of activation, so it has a structural component, determined by the neurons that converge on the synapse, and a temporal component, determined by the activity at that synapse. This structure makes it possible for convergence zones to have significant overlap, explaining how the same cells can be parts of different assemblies at different times to overcome the computational overload issues that traditional hierarchical views face. A third difference from the classical hierarchical approach is that convergence zones have back projections to the lower levels that are activated during recall and recognition. A convergence zone is initially generated by feed-forward activation from multiple sites, including sensory regions and regions subserving memory and motor processes, which converge to create the synaptic pattern. When activity in one region matches that which generated the convergence zone, the zone activates the other lower-level regions as well, reproducing the original pattern of activity in many or all of the lower levels. ‘I envision the binding code as a synaptic pattern of activity such that when one of the projections which feedforward to it is reactivated, firing in the convergence zone leads to simultaneous firing in all or most of the feedback projections which reciprocated feed-forward from the original set’ (Damasio 1989, 45–6). The pattern of activity binds lower-level processing in this way. Finally, convergence zones are not localized to one brain region. They can occur at many levels of processing, including intra- and inter-modal

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connections, explaining why damage to modal association cortices disrupts recall and recognition without affecting perception.4 The main advantage of the temporal synchrony view over the hierarchical view is that it overcomes the combinatorial explosion problem by using system dynamics, rather than structure, for binding. The contents encoded by different combinations of cells can be represented because the same cells can be parts of different assemblies at different times, by firing synchronously.5 However, despite the fact that there are many researchers now advocating temporal synchrony, there is the worry that synchrony is an effect of binding, rather than the mechanism realizing it: ‘even supposing that temporal coding is the vehicle for signaling which neural populations should be bound together, the theory does not adequately address how these combinations are computed. In a sense, the binding problem is pushed back one level, for it must be solved at least partially for the necessary temporal correlations to be established’ (Roskies 1999, 8). Temporal synchrony itself needs an explanation; whatever mechanism effects the synchrony seems to be the one actually doing the binding. It may be tempting to respond that the neurons fire synchronously because they are all responding to the same object but this just begs the question. The problem is to determine how an objectlevel representation is constructed from low-level representations of features being processed in distinct brain areas. Treisman uses the term ‘parsing’ to refer to this problem of how ‘the selected elements to bind as a single entity [are] selected and segregated from those belonging to other objects, ideas, or events’ (Treisman 1999, 105). The temporal binding hypothesis offers a view about how the brain can encode those features that have been selected for binding, not how they are selected. Recognizing the shortcomings of the temporal binding view, Ghose and Maunsell have a proposal that allegedly does not use temporal binding to overcome combinatorial explosion. They argue that a computationally tractable model with only arithmetic growth is sufficient to represent all of the featural combinations, provided that attributes can be tagged to a common label. ‘Any stimulus combination might be represented, however, if all the neurons that were activated by one object could be bound together with some type of label’ (Ghose and Maunsell 1999, 80). The idea 4 Barsalou argues for distributed property circuits that bear striking similarity to the systems connected via a convergence zone. Using data about macaque monkeys, he reports: ‘The auditory system processes the call, the visual system processes the faces and bodies of conspecifics, along with their expressions and actions, and the affective system processes emotional responses. Association areas capture these activations as they occur repeatedly, storing them for later representational use. When subsequent calls are encoded, they reactivate the auditory component of the resultant situational knowledge, which in turn activates the remaining components in other modalities. Thus the distributed property circuit that processes the original situation later represents it conceptually’ (Barsalou 2005, 309). 5 Note the parallels between combinatorial semantics and temporal synchrony. Both enable the production of vast numbers of representations from quite finite resources by employing those resources in combinatorial fashion as constituents of complex representations. As Jerry Fodor might say, this continues to be ‘the only game in town.’

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is that if attributes like red for color and round for shape are attached to a common label, the object the label corresponds to is red and round. Rather than requiring neurons to represent every combination, such as red and round, red and cubical, etc., there are simply neurons for each attribute. The total numbers of neurons required is then the sum for each attribute, not the product. As presented, this proposal greatly underestimates the number of combinations available, for the lowest level of processing is presupposed without explanation. Ghose and Maunsell consider how to avoid unmanageable combinations of neurons for attributes such as color or shape. But color, as we have seen, results from the differential responses of the three systems of cones. Any cone can be active or not, a geometric number of possibilities.6 At the level of attributes, a significant amount of binding may have already occurred. Nonetheless, much of the research in psychology has focused on binding attributes, so assuming the account can be supplemented, say with the sorts of proposals considered above, the idea that further binding can be avoided through a kind of labeling is very intriguing. In fact, it is essentially the solution that has been offered by psychologists, whose views we consider next.

15.3.3 Neuroscience and Representations Pulling back from the neuroscientific details, the materialist-cum-neuroscientific worldview is committed to the idea that mental representations are at least token identical with neural structures or events. To understand the identity, we must discover how mental representations are neurally encoded, including understanding how features being processed in distinct parts of the brain are processed as features of the same thing. So resolving the binding problem is one aspect of unraveling the neural code, which would show how a spatially distributed physical system can produce the experience of unity. If the underlying materialist assumptions are correct, this methodology of studying the architecture and operations of the brain at varying levels of specificity should uncover the neural code; however, at present the gap between our phenomenal experience with mental representations and our understanding of the neural code is too great to see directly how unifying representations in the sense required by P1 can be explained by the mechanisms we have considered. Psychology provides a bridge for that gap.

6 Having many-to-one projections from the lower-level, as Damasio (1989, 38) suggests, won’t help here because our color experiences result from the combined responses from the three systems of cones. At some level the combinations have to be resolved, and the combinations will be geometric at that level.

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15.4 Psychology and Binding 15.4.1 Cognitive Psychological Methodology Most of the experimental work on the binding problem in humans has been conducted in psychology, where, as in neuroscience, the main focus of research is on the binding of visual information. Subjects are asked to perform tasks that require visual identification and their behavior is measured in terms of rates and types of errors made, or reaction times. A type of error known as illusory conjunctions prompted the initial research on the binding problem (Treisman and Schmidt 1982). In experimental conditions, subjects presented very briefly with, for example, a red ‘X’ and a green ‘Y’ may report seeing a red ‘Y’, suggesting that somehow the shape of one object and the color of the other were erroneously bound together during processing. Subsequent psychological research on binding uses variations on a visual search paradigm, in which subjects are presented with a target stimulus and then (after a short interval) asked to determine whether that target stimulus is present in an array of objects. By varying such things as the features of the target, the size of the search array, and the similarity of the non-targets to the target and to each other, investigators test hypotheses about the nature of the underlying cognitive processes. The main point of the methodology is to discover functions into which the observed behavior can be decomposed. Of course, the functions must be such that they can be implemented by human brains, but understanding what kinds of operations our brains are performing at a functional level is an important step in discovering how binding occurs. At the level of behavior and function, many proposals for binding can be empirically tested based on predictions they entail about the effects of varying stimuli, in the manner mentioned above, on reaction time, errors, and error rates.

15.4.2 Psychological Proposals for Solving the Binding Problem The pioneering proposal for solving the (visual) binding problem in psychology is Anne Treisman’s (1982) feature integration theory (FIT). Treisman proposed FIT to explain phenomena related to subjects’ performance in searching for a desired item, called a target, defined by a conjunction of features. For example, subjects’ reaction times in finding a single feature, say red, by finding a red ‘X,’ the target, among green ‘X’s, the non-targets, is very fast and independent of the number of green ‘X’s. Such a reaction is called a pop out effect for the way the red ‘X’ seems to separate itself from the green ones. Finding a conjunction of features, red and ‘X’, by finding a red ‘X’ among green ‘X’s and red ‘Y’s is slower and does depend on the number of non-targets. Another behavioral phenomenon to be explained is that of illusory conjunctions, described above. What Treisman proposed to account for these data is a distinction between feature detection and feature binding.

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The early version of FIT viewed visual perception as incorporating two distinct processes. The first part of processing is a pre-attentive phase, in which discrete features of a visual stimulus (e.g. shape, color, orientation, motion) are coded independently and in parallel by feature detectors specialized for that particular feature type. Separate features of an object are coded by location, on an internal map for each feature type. This explains the ease with which a single feature is detected. If there is only one red ‘X’ present, its location is determined on the color feature map by the unique presence of red on that map. Conjunctions are more difficult because information on different feature maps must be correlated. Each feature map is linked by location to a master map of locations. However, it is not enough for perceiving a conjunction that the desired features are linked to the same location on the master map. To detect a conjunction of features, the location on the master map at which the conjunction occurs must be scanned by attention. Attentional search, conceived of with a spotlight metaphor, is serial and thus conjunction detection is slower than single feature detection, and dependent on the number of non-targets present, i.e. how many locations must be scanned. Duncan and Humphreys (1989, 1992) challenge Treisman’s early hypothesis that feature detection and feature binding are distinct processes that are pre-attentive and attentive, respectively, by providing empirical data it cannot explain. The time required to find an ‘F’ among ‘E’s, for example, depends on the number of non-targets, suggesting that the process is a serial attentional search, despite the target being defined by the single feature, shape. Also there are conditions under which conjunctive searches are not dependent on the number of non-targets; reaction times show a pop out effect. For example, if the target is a horizontal red bar, among horizontal green bar and vertical red bar non-targets, reaction times do not increase linearly with the number of non-targets. Duncan and Humphreys (1989, 1992) explain the effect by denying the alleged difference between feature detection and feature binding. According to their Attentional Engagement Theory (AET), the differences in search times result from the relative similarity of the target to the non-targets and of the non-targets to each other, regardless of whether the target is defined by a single feature or a conjunction of features. AET is motivated by empirical data showing that if the target and non-targets are very similar, as in the case with ‘F’ and ‘E’s, search is slower, as it is if the non-targets are quite heterogeneous. Duncan and Humphreys explain this by postulating two mechanisms. First, the target defines a kind of template against which information about search elements is compared for a match. Based on the degree of similarity, there is a certain probability that the information will be sent to a short-term store for further processing. A second mechanism groups search items according to their similarity to each other. The effect of this grouping is referred to as ‘spreading suppression’ because the likelihood of a search element being sent to the store can be reduced in virtue of the groupings. In effect, very similar non-targets are rejected as a group, explaining pop out effects. Heterogeneous non-targets cannot be grouped, so search is slower. The data presented by Duncan and Humphreys is incompatible with the early version of FIT and caused Treisman to reformulate the view. In its current form,

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FIT still maintains a distinction between feature detection through an individual feature map and feature binding through a master map of locations. The distinction is not that detection is pre-attentive while binding requires attention, however. All search proceeds via attentional selection operating on the master map of locations. Attentional selection can be thought of as a window of variable size placed over the master map of locations. Only those regions in the window are attended to. Activity on the individual feature maps can aid search by inhibiting locations on the master map where non-target features occur. For example, if the target is a vertical green bar, then the orientation feature map can inhibit locations where horizontal bars occur. Inhibited locations are passed over in the serial attentional scan, reducing the number of locations that need to be searched. The current version of FIT explains the data presented by Duncan and Humphreys as follows. Targets can be so similar to non-targets that there is no single feature—no primitive, like green or vertical, in terms of how the features such as color or orientation, are processed—possessed only by the non-targets, as is the case with ‘F’ and ‘E’s. In such a case no locations are inhibited, thus even a single feature search requires a serial scan of the master map of locations. In some conjunction search tasks inhibition is possible, so reaction times can exhibit a pop out. In the case of the target being a horizontal red bar, among horizontal green bar and vertical red bar non-targets, locations of search elements that are green or vertical are inhibited, leaving the location of the target element to pop out during attentional selection. It may seem that the current version of FIT accounts for the data motivating AET in much the same way as AET itself, but inhibiting locations on the master map is not the same as spreading suppression among non-targets. (Treisman 1992) demonstrated this difference by comparing reaction times for searches involving two types of non-targets with reaction times for searches with three types of non-targets. The case with two non-targets is set up so that according to FIT and AET search is a slower serial scan because of target/non-target similarity—according to FIT there is no inhibition and according to AET there is no spreading suppression. The three non-target case uses the same non-targets as in the two non-target case plus one more. The third type of non-target has no features in common with the target but does share features with the other two types of non-targets. In this case, FIT predicts the search will remain serial, since inhibition is still precluded. On the other hand, reaction times should decrease according to AET because the third type of non-target should have the effect of spreading suppression to the other non-targets. The evidence supports FIT and this seems to have ended the debate in favor of FIT (Quinlan 2003).7

7 Another alternative to FIT, known as Signal Detection Theory (SDT) was suggested by Palmer et al. (1993). SDT offers an explanation for the Duncan and Humphreys’ data in terms of signalto-noise ratios. Every signal has noise in it, so the more similar the non-targets to the targets and the greater the number of non-targets, the greater the noise-to-signal ratio, which makes the task harder. On SDT, target search becomes a decision procedure about which is the correct signal given the noise, rather than a perceptual mechanism as suggested by FIT. The role of attention is simply

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In reformulating FIT, the actual process of binding is also further articulated. Binding is more than just a collection of features projecting to the same location on the master map of locations. It requires attentional selection of that location on the master map in order to identify a search element as having all of those features. In other words, binding is a result of treating locations as the locations of search elements, i.e. objects. For each location attended, an object file—a temporary episodic representation—is opened (Kahneman, Treisman, and Gibbs 1992). The features active at a location are recorded in the corresponding object file; features are bound to an object by being included in its object file and they are bound to each other simply by being features of the same object, i.e. by being included in the same object file. The notion of an object file has subsequently gained widespread support in psychology and considerable empirical evidence has been presented in its favor (e.g. Feigenson and Carey 2003, Pylyshyn 1999, 2003). Feature binding is understood as a psychological process of tagging features to object files, which serve as labels, just as Ghose and Maunsell (1999) propose in the neurosciences. A difficulty for the FIT account of object files is that they are location based. It is possible to have different objects occupy the same space, such as a red square circumscribed by a green circle. Binding is needed to represent the square as red and circle as green and not vice versa. But since they occur at the same location, there is only one object file available. Considerations such as these, plus many others about visual tracking, have led Pylyshyn to propose that object files attach to visual indexes (also known as FINSTs, for FINgers of INSTantiation) (Pylyshyn 1999, 2003). According to Pylyshyn, we have four to five visual indexes that directly track objects. Pylyshyn has shown that multiple objects can be tracked even as they move within a large array of similar objects, including conditions in which they pass under occluders. Attention is directed only to objects that are indexed, making it possible in principle to track an object without representing a single feature of the object. Over the time in which an object is attended, its features are processed and listed in the object file associated with its visual index. The index itself is a referential pointer to the object that is without content, except for perhaps the ‘thatness’ defined by its functional role. The content of a visual representation is recorded in the object file. Of course, a visual index must be locked to an object via some property; it just need not be any property we explicitly represent, i.e. list in the object file. This is true on both Pylyshyn’s and Treisman’s accounts, however. The main motivation for originally positing object files was that seeing an object is considerably more involved than merely type identifying it. ‘To generate a perceptual experience and to be able to act on it, we need to specify the current details of how an object looks, where it is, how it is oriented, and many other often arbitrary details of its current instantiation’ (Treisman 1999, 105); seeing an object is subject to the contingencies of the viewing circumstances. Given the dynamics of the environment, the circumstances are often quite variable. It is an object file ‘within which successive states

to improve the signal-to-noise ratio. SDT is more parsimonious in positing mechanisms than FIT, but it offers no feature binding mechanism (Quinlan 2003, 660), so we do not discuss it further.

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of an object are linked and integrated’ (Kahneman et al. 1992, 175). But since the features listed in the object file are variable, they cannot be those by which the object is tracked from moment to moment. The problem is to determine to which object file a feature should be tagged. Both accounts require a mechanism that makes this low-level perceptual tracking possible.8 Understanding that mechanism will take us a long way toward understanding binding and may help adjudicate between FIT and FINST, but just recognizing what is needed can guide productive future research into the binding problem.

15.4.3 Psychology and Representations The cognitive sciences proceed via a divide and conquer strategy. Some cognitive phenomenon is decomposed into simpler functions, iteratively, until it is decomposed into a collection of primitive functions simple enough to be physically realized in a human brain. In particular, the phenomenon of representation is decomposed into specific sensory modalities, which are further decomposed into feature detectors that are neurally implemented.9 Psychology plays the essential role of bridging the gap between our understanding of a phenomenon at a conceptual level, as it appears in philosophical problems, and neural implementation of the phenomenon. The empirical work in psychology on the binding problem we have just reviewed is attempting to fill just this gap. Subjects are presented with tasks posed at a conceptual level: search for an ‘X’, track certain items, etc. In measuring reaction times, errors, and error rates, psychologists transform the highly conceptual problem of explaining binding into a more tractable problem of accounting for the data they have generated, data dependent on our binding abilities. The data helps psychologists posit mechanisms of the hybrid sort needed to bridge the conceptual/implementational gap, such as feature maps, object files, and visual indexes. Thus, the psychological account is essential for explaining how neural processes such as those we considered in Section 15.3 could count as representations of the sort referred to in P1, thereby showing how a distributed brain can produce our experiences of unified objects.

15.5 Binding Disciplines Having completed our survey, we summarize the main proposals for binding, the challenges they face, and suggest a way of combining them that may hold more promise than any theory on its own for solving the binding problem. Our review

8

Properties such as onset are claimed to lock visual indexes, but they cannot be those that sustain the tracking. The problem of tracking is compounded by the fact that we track objects through occlusion. 9 Again this is the tri-level hypothesis presented in Dawson (1998).

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of the neuroscientific and psychological literatures on the binding problem has revealed three broad classes of proposed solutions: grandmother cells, temporal synchrony, and object files. Unfortunately none of these solutions is adequate on its own. Grandmother cells, at least as a general account of perception, are untenable because of combinatorial explosion. Temporal synchrony and object files both seem to require some prior mechanism relevant to binding. In the case of temporal synchrony, something must establish the synchronous firing rate among the to-bebound processes. Object files also require some kind of mechanism to track objects so that features can be listed in the correct object files. There is a feeling in studying this problem of being a victim of the Greek gods; like poor Tantalus, just as one approaches a solution it recedes. Still, though entirely speculative on our parts, we believe that putting the various ideas we have considered together, the prospects of finding a solution for how some binding occurs, specifically feature binding, seem somewhat brighter.10 With neuroscientists and psychologists alike proposing some kind of binding by tagging, it seems to us worth considering how tagging might be achieved. Given the mechanisms we have reviewed, one possibility is that synchrony acts like a tag. In that case, opening an object file could be implemented by synchronizing the appropriate neural signals. Combining Damasio’s convergence zones with Newman and Grace’s selective gating, we get a glimpse as to how this might occur. Recall that convergence zones are defined by synaptic patterns of activation and that the activation can reactivate systems that contributed to establishing the pattern. Thus, when some activation that matches a pattern occurs, the convergence zone can help regulate activity in the early perceptual systems, possibly establishing synchrony. Interestingly, ‘the entorhinal cortex and the sequence of cellular regions in the hippocampus to which it projects . . . is the only brain region in which signals originally triggered by neural activity in all sensory cortices and in centers for autonomic control can actually co-occur over the same neuron ensembles’ (Damasio 1989, 53). This subsystem is not a place where all representational content comes together, but it is a site that could regulate all perceptual activity. Given the role that the hippocampus plays in memory, it is possible that incoming patterns are matched to familiar patterns in memory, which sets up the appropriate activation in the convergence zone to be fed back to the perceptual systems. Such a process might establish synchronous firings for object tracking, precluding the need for some further mechanism.11 Furthermore, since the hippocampus controls selective gating—the determination of what signals receive further processing—as we saw in Section 15.3, the firing rates which will pass through the gates for further processing could be those established through the convergence zone; the same patterns could

10

Quinlan (2003) sees progress for FIT coming through investigating neural mechanisms of implementation, an avenue that is currently being explored. 11 This may, indeed, be what Damasio intends, in which case we are simply making explicit that this is a means for establishing synchrony in a non-question begging manner.

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be fed forward and backward through the system, determining what activity higher cognitive functions will process.12 The model we are proposing would explain why Pylyshyn’s research has found evidence for such a small number of visual indexes (4–5). Tracked objects would be processed at different synchronized firing rates, to keep them distinct. Since there is only a limited range of possible firing rates, the range can only be divided into a small number of non-overlapping bands, which would correspond to the visual indexes. The selective gating of bands of synchronous activity could be the mechanism corresponding to opening an object file. Information about features encoded at the same rates passes through the selective gate for further processing. Attention might be nothing more than the further processing occurring after gating, explaining why attention is associated with binding, without making attention some additional to-be-explained mechanism or process. Features of attended objects are bound simply by being treated as features of the same object in further processing because of their synchronous firing rates. Our proposed combination of the mechanisms reviewed avoids the problem of pushing the problem of binding back one step. Pattern matching of incoming signals to those stored in memory establish synchronous firings rates, without the need for an additional mechanism to determine which signals should be synchronized. Synchrony avoids the combinatorial explosion of grandmother cells and establishes what features are entered in which object files. How we parse the world depends on our previous experiences. However, whereas the proposed solutions we have reviewed seemed to push the binding problem to an earlier stage, what we have proposed pushes it to a later stage, bringing us full circle to the Achilles argument. ‘Perhaps the most crucial question is this: how is the output of the binding process interpreted and used by later stages’ (Treisman 1999, 110)?

15.6 The Subject of Binding: the Bio-representational Imperative The proposals we have reviewed are of philosophical interest in suggesting mechanisms by which processing of different features of an object is coordinated and bound. Nonetheless, if we are to have an answer to the conceptual problems posed by the Achilles, we must move up from the neural-implementational and architectural levels of description back to the conceptual level, and conceptually there is only

12

It might be objected that gating occurs at too low a frequency (below 8 Hz). The answer to this question might address an issue for which we did not find an explanation. On the assumption that the information a neuron conveys is carried in its firing rate, its rate cannot be adjusted to match that of another neuron without altering the informational content. How then is synchrony established? If all that is adjusted is the phase of firing but not the rate, the content will remain unaltered. Nonetheless, phase adjustments can result in neurons being synchronized on many firings, establishing the population-level peaks. However, the rate of peaks will be much lower than individual firing rates. For example, if one neuron is firing at 40 Hz and another at 25 Hz, peaks will occur at a rate of 5 Hz (the greatest common factor of the two rates).

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one proposal for unifying representations: tagging; to be bound is nothing more than to be represented as being bound. What we want as philosophers is a non-circular account of what it is to be represented as being bound, which it seems will inevitably require discussion of P2. Let us suppose that a complete account of the binding mechanisms were available, including the process of tagging whatever is to be bound. Even so, tagging will only count as binding if there is something that can make use of the tags and in such a way as to make us conscious of a unified representation.13 In short, binding requires an account of the subject of experience. The reasoning in the Achilles is that genuine unification requires a simple substance as unifier and presumably subject of the unified representation. But tagging as a solution to binding is more like a set of instructions as to what fits together and how, than unification of the sort imagined in the Achilles. So what is required of the subject is that it can use the instructions, and such a subject need not be a simple thing. Indeed, it need not be a single thing; many parts of the nervous system might make use of the information about what is tagged as being bound. What phenomenology requires is that the subject of experience is represented as a single thing in introspection, which, of course, is what Kant proposed as a solution to the Achilles (see Harper: above). However, understanding the neurological and psychological mechanisms that implement binding provides a motivation for the represented subject not offered by Kant. We agree with Kant, that a represented subject of experience is present in our conscious thoughts: the question is why? The architecture of the brain offers some clues. Sensory processing begins in independent and relatively isolated subsystems.14 Determining appropriate behaviors based on sensory information requires not only integrating the information (binding) but also disseminating it. Visual information isn’t much good if it stays within the visual system. Information can be disseminated simply by being used, as it is in dorsal visual stream processing for actions.15 It can also be disseminated by being represented—a report on what information is being processed in a particular subsystem. A representation of information is a higher order representation, taken by many to be a conscious thought.16 What is crucial about a higher order representation is that it has a first order representation as its 13

This raises the specter of the hard problem of consciousness, the problem of explaining why it is like something to be in certain mental states (Chalmers 1996). In our discussion, we will simply take it for granted that it is like something to be in certain mental states and attempt to see what is involved in getting the correct content of those states. 14 We are not taking a particular stand on their modularity here. Their independence need not entail any of the functionally defining features of a module (see Fodor 1983), though it would hardly be surprising if these subsystems are modules. 15 Milner and Goodale (1995, 2004) argue that visual processing separates into a dorsal stream for fast-acting real-time responses, and a ventral stream for object recognition relevant to higher reasoning. 16 The leading proponent of the higher order thought theory of consciousness is David Rosenthal (1993, 2005). Dennett (1991) and Carruthers (1996) hold higher order dispositional views of consciousness. Our purpose here is not to argue for a higher order theory, but to the extent that what we are proposing is successful, it can be taken as support for these views.

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content. And importantly, a first order representation has a subject, in at least the weak sense that it must function as a representation for something. So the content of a higher order representation must include the subject of the first order representation. The subject must be represented. But if the whole point in producing the higher order representation is to disseminate information, there is no determinate subject. The brain is faced with the problem, which we refer to as the bio-representational17 imperative, of having to represent an unknown subject. Our suggestion for how the brain overcomes the problem of representing the unknown subject is that it makes the best guess it can under the condition that disseminated information might be used anywhere in the nervous system, including moving any muscle, directing any sense organ, or reasoning. As a default, the brain draws the smallest boundary it can so as not to exclude any system that might use the information, and the tightest bound possible is the entire body throughout which the nervous system extends. Hence the brain uses its objective representation of its body as a placeholder for the subject. The result is that all of our conscious thoughts are experienced as thoughts of which the body is subject, creating the phenomenal unity of consciousness over time and unity of subject and object.18 Putting all of this together, when we have a conscious experience of an object, we have a higher order thought representing the body as the subject experiencing the object, which itself is represented by a label and features tagged to that label. The higher order thought is the thought that I am seeing an object with such and such features, those tagged to the label. The content of the features is (first-order) represented in the appropriate perceptual system. So in effect binding is not the unification of representations, it is a representation of independently processed features as unified. Rather than explaining P1, tagging as a solution to binding denies it, as Dennett (1991) does. Our analysis reveals that what is on offer is not a way of unifying representations without appeal to a simple substance as the methodology suggests, but an explanation of how representations can seem unified.

15.7 Concluding Remarks Despite the advances that have been made in the cognitive sciences, the conceptual framework for solving the binding problem, the Achilles in the twenty-first century, is that set out by Kant. We may have to be content with the fact that, however counterintuitive, grasping a thought just is distributed neural activity, smeared across the brain both spatially and temporally.19 Cognitive science can provide us with 17

We choose ‘bio-representational’ to be ambiguous between the biological constraints on representing the subject and the biographical constraints, i.e. coherence of history central to subjective unity. 18 We have not addressed how the represented subject results in a first-person perspective. An interesting hypothesis about how this is achieved that could supplement our view is grounded in proprioception and general bodily awareness (Anderson and Perlis 2005). 19 This is the view Dennett (1991) expresses.

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psychological theories that bridge the gap between experience and the mechanisms responsible for experience and neurological theories of how those mechanisms are implemented in human brains. Our discussion has focused on efforts to achieve such theories for feature binding in vision, since this has been most studied and is best understood. Ultimately full accounts of all types of binding are needed; however, a single complete account of tagging as discussed above would serve as a counterexample to the Achilles. The seeming unity of representations is a result of tagging the to-be-unified elements as belonging together, and the seeming simplicity of the subject is a consequence of how it is represented. If this is unsatisfying we must remember, ‘there is a transcendental ground, constraining us to draw a formally invalid conclusion. Such a fallacy is therefore grounded in the nature of human reason, and gives rise to an illusion which cannot be avoided, although it may, indeed, be rendered harmless’ (Kant A341–B399). The continuing role of the cognitive sciences is to explain the processes of thinking in sufficient detail to remove all mystery and, indeed, render the illusion of unity, of both representations and subject of experience, which gives rise to the Achilles, harmless.

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Author Index

Ablondi, F., 141 Adams, R. M., 165 Alexander, S., 49, 50, 53, 73, 81, 217 Allison, H. E., 215 Altmann, A., 217, 219, 222 Ameriks, K., 227, 229 Anderson, M., 274 Aquinas, T., 10, 13, 75, 79, 81–83, 87, 91, 164, 165 Aristotle, 1, 10, 12–13, 24, 35, 38, 41, 43–57 Arnauld, A., 14, 151, 152, 154, 183, 187, 188 Attfield, R., 159 Averroes, 48, 87 Ayers, M. R., 163 Barsalou, L. W., 264 Bayle, P., 1, 4, 11, 14, 94–100, 104, 111, 116, 139–142, 144, 146–158, 186, 193, 195, 198, 200–201, 203–205 Beiser, F. C., 220 Bennet, J., 220 Bernard, W., 61 Blackwell, R. J., 189 Bouillier, F., 154, 155 Brook, A., 237–239 Buridan, J., 14, 75–76, 89–91 Burnyeat, M. F., 12, 29, 31, 32, 33, 34, 37, 38, 40 Burr, D., 83 Campbell, N. A., 73 Carey, S., 269 Carruthers, P., 273 Caston, V., 73 Chalmers, D. J., 273 Charlton, W., 47 Clarke, S., 1, 4, 8, 9, 14–15, 159–175, 193–195, 198, 200–204, 208 Condillac, E. B., 8, 146, 193, 203

Cooper, J. M., 30, 31, 37 Cornford, F. M., 24, 30, 35, 37, 157 Crick, F., 262 Cudworth, R., 1, 3, 14, 139–149, 153, 155–158, 193–194, 198–205, 211 Damasio, A., 262–263, 265, 271 Dawson, M. E., 259, 270 Dennett, D. C., 258, 273, 274 Descartes, R., 1, 5, 12, 91, 93, 101, 106–108, 121, 136, 137, 141–143, 146, 148, 154–155, 159, 164–165, 169, 189, 208, 215, 241 De Sousa, R., 88 Dillon, J. M., 67, 68, 69 Donagan, A., 93, 109 Duncan, J., 267–268 Emilsson, E. K., 64 Engel, A., 261 Falkenstein, L., 2, 16, 19, 20, 22, 27, 96, 113, 145, 146, 167, 193, 194, 220, 221 Farber, P. L., 141 Feigenson, L., 269 Fichte, J. G., 17, 216, 224, 225, 232–233 Fine, G., 30, 31, 37 Fodor, J. A., 7, 264, 273 Foucher, S., 28, 146, 157–158 Frede, M., 37 Gerson, L. P., 67, 68 Ghose, G. M., 257, 264–265, 269 Gill, M. L., 21 Goodale, M., 273 Grace, A., 258, 262, 271 Grier, M., 229, 230 Gross, C., 261 Guéroult, M., 93, 109

287

288 Guyer, P., 216, 235, 243, 246 Gysi, L., 142 Hamlyn, D. W., 49–50 Harper, W., 235, 241, 273 Harte, V., 71–74 Hasse, D., 78 Hicks, R. D., 50 Holden, T. A., 170 Hume, D., 6, 10, 13–16, 93–104, 107–108, 110–113, 139, 141, 149, 150, 154, 158, 193–198, 200–214, 249, 251–253 Humphreys, G. W., 267, 268

Author Index Malebranche, N., 8, 12, 14, 51, 117–119, 128, 134, 135–136, 146, 149, 151–155, 157, 182, 194, 195, 207–208 Matthews, G. B., 76 Maunsell, J., 257, 264–265, 269 Mendelssohn, M., 1, 3, 4, 12, 16–17, 19, 20, 21–28, 34, 40, 139, 193, 203, 215–229, 231–232 Mijuskovic, B. L., 2, 12, 22–24, 26, 28, 40–41, 75, 77, 82, 93, 94, 96, 98, 99, 123, 125, 130, 157, 178, 194, 202 Milner, D., 273 Mori, G., 141

Irwin, T. H., 38, 41 Jakubowicz, S., 52 James, W., 1, 8, 12, 17, 23, 247–255 Kahn, C., 53 Kahneman, D., 269, 270 Kandel, E. R., 259 Kant, I., 1, 4–6, 11–12, 16–17, 19, 20, 22–27, 34, 41, 65, 94–97, 110, 115, 139, 141, 146, 148, 149–150, 155, 158, 166, 177, 181, 193–194, 198, 203, 215–216, 219–223, 225–231, 235–246, 251, 254, 258, 273–275 Kemp Smith, N., 20, 93, 115, 149, 177, 235, 243, 246 Khalidi, M. A., 78, 79 Kitcher, P., 215, 229 Knuuttila, S., 91 Koch, C., 262 Kuehn, M., 216 Lagerlund, H., 75, 88, 89, 91 Leibniz, G. W., 1, 15, 19, 22, 51, 88, 141–142, 147, 159–161, 163–165, 169, 172–174, 177, 178–191, 218 Lennon, T. M., 1, 14, 24, 109, 113, 139, 146, 152, 207, 257 Locke, J., 1, 4, 10, 14, 25, 35, 48, 115–131, 133–137, 141, 146, 159, 160, 163, 182, 184 Lodge, P., 146 Longuenesse, B., 223, 228 Lorenz, H., 38 Lotze, H., 1, 4, 8, 248 Lovejoy, A. O., 23–24 McGrade, S. A., 89 McRae, R., 165

Newman, J., 258, 262, 271 Newton, I., 93, 107, 172 Olivi, P. J., 13, 75, 77, 83–88, 91 Osler, M. J., 141 Palmer, J., 268 Pasnau, R., 83 Passmore, J., 156 Penelhum, T., 252 Perlis, D. R., 274 Philoponus, J., 13, 53, 60, 61, 67, 69 Plotinus, 1, 5–6, 8, 12–14, 22–24, 26–29, 38, 41, 59–67, 70–74, 115, 124, 127, 131, 142, 144–146, 157, 178, 182, 198, 204 Porter, N., 117 Price, A. W., 78 Proclus, 1, 8, 13, 60–61, 65, 67–69, 71, 87, 116, 142, 166, 175 Pylyshyn, Z., 269, 272 Quinlan, P. T., 268, 269, 271 Quiroga, R. Q., 261 Rahman, F., 78, 79 Raymond, D., 55 Reece, J. B., 73 Reid, T., 194 Robinet, A., 159 Rodier, G., 44, 47 Rosa, S., 156, 157 Rosenthal, D. M., 273 Roskies, A. L., 264 Ross, D., 51, 258 Rozemond, M., 15, 159 Russell, P., 194 Ryan, T., 2, 156

Author Index Sassen, B., 215 Schachter, J., 10, 14–15, 25, 115, 133–134, 136, 141–142, 148, 153, 156, 160, 177 Schmidt, G., 266 Schouls, P., 117 Searle, J., 150 Shadlen, M., 165 Simmons, A., 165 Singer, W., 261 Smith, J., 14, 116, 123–125, 139 Sophonias, 50, 53 Sorabji, R., 61, 91 Spinoza, B., 8, 11–14, 93–94, 98, 107–113, 140, 146, 209–210

289 Taylor, A. E., 26 Themistius, 50, 53 Treisman, A., 258, 264, 266–269, 272 Vailati, E., 170, 172, 174 von der Malsburg, C., 261, 262, 263 Wallace, E., 44 Watson, R. A., 146 Wilson, M., 164, 181 Yolton, J. W., 133, 160, 194, 195, 207, 208 Yrjönsuuri, M., 84, 87 Zavalloni, R., 87, 88, 89 Zupko, J., 89