Locke on Essence and Identity (Philosophical Studies)

LOCKE ON ESSENCE AND IDENTITY

PHILOSOPHICAL STUDIES SERIES VOLUME 98

Founded by WilfridS. Sellars and Keith Lehrer

Editor Keith Lehrer, University ofArizona, Tucson

AssociateEditor Stewart Cohen , Arizona State University, Tempe

Board ofConsulting Editors Lynne Rudder Baker, University ofMassachusettsat Amherst Radu Bogdan, Tulane University, New Orleans Marian David, University ofNotre Dame Allan Gibbard, University ofMichigan Denise Meyerson, Macquarie University Francois Recanati, Institut Jean-Nicod, EHESS, Paris Stuart Silvers, Clemson University Barry Smith, State University ofNew York at Buffalo Nicholas D. Smith , Lewis & Clark College

The titles published in this series are listed at the end of this volume.

LOCKE ON ESSENCE AND IDENTITY by

CHRISTOPHER HUGHES CONN The University of the South, Sewanee , TN, U.S.A.

KLUWER ACADEMIC PUBLISHERS DORDRECHT I BOSTON I LONDON

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ISBN 1-4020-1670-0

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CONTENTS

PREFACE........•..••..•••••.••••••.•••.•••••••.••••••..•••..••••••••.•••..•....•.......•..•....•.•.•••..••••••.•.•.•.••• ix INTRODUCTION ..••.•......•..•.•....••...•..•.•...••..•.•.••••••••.••••.••.•••••••..•.••.•.•.••••.•.••••.•..•••.•..1 1

I. SUBSTANCES , ESSENCES, AND KINDS

I. Substances and the Spatiotemporal World 2. Substanc es and their properties 3. Essential properties and natural kinds

1 8 IO 12

II. IDENTITY AND P ERSISTENCE

I . Identity 2. Persistence 3. Identity, persistence, and Lockean anti-essentialism 4. A brief look ahead LOCKE'S CRITIQUE OF ESSENTIALISM I. LOCKE ON THE ACCIDENTAllESSENTIAL PROPERTY DISTINCTION

I . The sortal relativity of essential properties 2. Unsorted particulars and accidental properties 3. Real essences of sorted and unsorted parti culars II. LOCKE ON THE NATURE AND EXISTENCE OF NATURAL KINDS

I . The "second opinion" regarding natural kinds 2. The "fi rst opinion" regarding natural kinds 3. Locke 's epistemological and semantic arguments against real kinds 4. Locke 's appeal to monsters and changelings III. LoCKE ON THE CLASSIFICATION OF CORPOREAL SUBSTANCES I . Sorting particulars into kinds 2. Forming sortal concepts IV. LOCK E ON KINDS AND PARTICULARS

v

12 20 22 24 25 26 26 28

30 32 33 36 40 44 47 47 49 53

CONTENTS

VI

LOCKE'S THEORY OF IDENTITY I. LOCKE 's C ONCEPT OF IDENTITy

1. The psychological origin of this concept 2. Diachronic and synchronic identity-statements II. LOCKE 'S PRI NCIPLE OF INDIVIDUAnON

1. Locke's argumen tfor the principium individuationis 2. Three obje ctions

55 56 56 57

62 63 71

III. IDENTITY AND THE IDEAS OF TH INGS

74

1. General ideas and persistence conditions 2. Locke and the relative identity thesis IV. D OES LOCKE HAVE A C ONSISTENT THEORY OF ID ENTITY? 1. Two accounts of persistence 2. A metaphysical dilemma

83 92 93 96

75

LOCKE ON THE PERSISTENCE OF ORGANISMS AND PERSONS••...•••• 101 I. O RGANISMS AND THEIR M ATERIAL P ARTS

1. Atoms and masses 2. Organisms, Masses, and Lives II. L OCKE' S ORGANISMIC THEORY OF P ERSONAL IDENTITY

1. Persons, consciousness, and the nature ofthinking substances 2. Consciousness as the "life" ofpersons 3. What conscious ness might do 4. The temporal extent of Lockean organisms 5. The temporal extent of human persons 6. Organisms, persons, and their temporal stages III. LOCKE' S THOUGHT EXPER IMENTS AND PR OBLEM C ASES

1. Cases involving lapses of memory 2. Cases involving two persons and one man 3. Cases involving one person and two men 4. The case of the conscious, severed fin ger IV. C ONCLUSION

102

102 103 113

113 123 126 133 135 136 139

140 141 142 143 144

OBJECTIONS AND REPLIES ..•••...•............••..•••••..•.•••••.•..••.••........•.................. 147 I. T HE CH ARGE OF ANAC HRONISM

1. Initial response 2. Some historical counterexamples to the charge ofanachronism 3. Locke's views on space and time II . FOU R-DIMENSIONAL B ODIES AND THE C ORPUSCULARIAN H YPOTHESIS

14 8

148 150 155 161

CONTENTS 1. The temporal extent ofLockean atoms and masses 2. Locke and Newton on the creation ofmaterial corpuscles 3. The temporal extent ofNewtonian bodies 4. The mobility oftemporally extended bodies III. CONCLUSION

vii 161 163 168 170 173

RELATIVISTIC ANTI-ESSENTIALISM AND A FOUR-DIMENSIONAL LOCKEAN ONTOLOGY 175 I. THE ANTI-ESSENTIALIST IMPLICATIONS OF A FOUR-DIMENSIONAL LOCKEAN ONTOLOGY

1. The sortal relativity offour-dimensional persistence conditions 2. Four-dimensional persistence conditions and the relative identity thesis 3. Four-dimensional persistence conditions and Lockean anti-essentialism II. Two OBJECTIONS

1. A three-dimensionalist alternative 2. An alleged essentialist implication offour-dimensionalism III. CONCLUSION

176

176 177 178 181

182 184 190

BmLIOGRAPY

193

INDEX

205

PREFACE

I first became interested in the relationship between Locke's antiessentialism and his theory of identity in a first-year graduate course on metaphysics taught at Syracuse University by Jose Benardete. I had until then approached Locke as a "safe", commonsense philosopher, whose metaphysical agenda-constrained as it was by his concept empiricismwas largely geared towards upholding a scientifically enlightened, broadly Christian worldview. I am greatly indebted to Professor Benardete for disabusing me of this understanding of Locke's work. Benardete's Locke was not the Locke that I had been exposed to as an undergraduate, not the Locke that I had found in Copleston's History of Philosophy. Rather, he was a profoundly creative and audacious metaphysician, who was justly perceived to be a tremendously dangerous philosopher by his more traditional contemporarie s. And as much I had admired Copleston's Locke, I have become positively enthralled with Benardete's. The topics of identity and essentialism have become mainstays of contemporary metaphysics, and it is no understatement to say that Locke's contribution to modem debates on these matters is enormous. My early interest in Locke's work on essentialism and identity-through-time was motivated by two factors. First, although there are a number of obvious and significant conceptual connections between these topics, Locke's own theorizing about identity seems not to have been informed by his critique of essentialism or vice versa. Given the philosophical and historical importance of these theories, Locke has left us with some important work to be done, namely, that of precisely mapping out their logical relationship. And although a few writers have taken up this issue in passing, it has yet to receive the sort of detailed attention that it deserves. It is my hope that the present work will at least partly fill this lacuna. Second, I found it difficult to escape the conclusion that his treatment of identity is baldly inconsistent with his anti-essentialism, inasmuch as he gives persistence conditions for particulars objects in a manner which seems to involve a commitment to some sort of essentialism. The present work is a substantially revised version of the doctoral dissertation which I wrote at Syracuse University under the guidance of Jonathan Bennett. It would be difficult for me to overstate my gratitude for Professor Bennett's advice and encouragement. There probably isn't a ix

x

PREFACE

single section of this work which wasn't significantly influenced by his comments on earlier drafts. If there has ever been a more helpful dissertation advisor, a more devoted scholar, or a more effective teacher of philosophy, I have yet to hear about it. I would like to thank Professor Bennett, in addition, for teaching me two things about the discipline of philosophy: first, that the real work of a philosopher is profoundly difficult, more difficult, perhaps, than one could ever have imagined; and second, that this work pays off in all sorts of ways, and in particular, that it helps us to become much better at reading, writing and thinking than we otherwise would have been. I can only hope that this work, if not my entire career, will embody these insights in something like the way in which his own work has. It is to him, then, that this work is dedicated. Portions of this work have already appeared in print. Most of Chapter Two appears in the Journal of Philosophical Research (Conn, 2002a); most of Chapter Four appears in Locke Studies (Conn 2002b); and a significant portion of Chapter Five appears in the British Journal for the History of Philosophy (Conn, 1999). I would like to thank the editors of the journals for graciously allowing me to reprint these materials. I would also like to thank Michael Jacovides of Purdue University for his extremely helpful comments upon the penultimate version of this work. I am confident that the final version is much stronger as a result. Needless to say, I am solely responsible for any errors which remain. Finally, I would like to thank my wife Debra for her love and support throughout the entire history of this project.

1

INTRODUCTION

This is a book on Locke' s metaphysics. In particular, this book is concerned with the relationship between Locke's rejection of essentialism-the thesis that some objects have essential properties independently of how they are characterized-and his theory of identity and persistence, especially as it relates to organisms and persons. While I will develop Locke's positions on these topics in detail in the ensuing chapters, my goal in the present chapter is to explain, in general terms, why these issues are worth thinking about, how we should begin, and where his views fall within the range of theoretical alternatives. I will subsequently be in a position to develop what I take to be the central problem of the book, namely, that of determining whether Locke's rejection of essentialism is consistent with his treatment of identity and persistence. I. SUBSTANCES, ESSENCES, AND KINDS

1. Substances and the Spatiotemporal World

The object which we refer to as the cosmos fills an enormous region of space and time. While there have been a few philosophers who think that there is no such thing as the spatiotemporal world, there have been even fewer who think, with Spinoza, that it is the only thing which exists. Most of us, including Locke, allow for the existence of countless multitudes of entities (such as baseballs, baseball players and baseball games) whose "careers" are associated with vastly smaller regions of space and time. This naturally brings us to the idea that the world is "cut" or "chopped" or "divided" up into the particular objects which we encounter throughout the day. This thought, in turn, forces us to confront a difficult but important question: (Ql) Does the cosmos already come to us divided up into particular objects, or are these divisions something which we impose upon the world, in accordance with some sort of a "conceptual scheme"?

C. H. Conn (ed.), Locke On Essence and Identity © Kluwer Academic Publishers 2004

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CHAPTER ONE

With respect to any given set of such divisions (and the objects which they delineate) , it would seem that one must either be a metaphysical realist, or else that one must be some sort of a conventionalist, where the realist affirms and the conventionalist denies that these divisions and objects exists independently of our beliefs and classificatory decisions.' As spatiotemporal objects, the objects which we have come to acceptwhether as realists or conventionalists-have both spatial boundaries and temporal boundaries. This point, though obviou s, gives rise to another difficult question: (Q2) How are spatiotemporal objects related to their spatiotemporal boundaries? In his seminal paper "Four Ontologies" (1970), Eddy Zemach shows that with respect to any given object and either of its dimensional boundaries, there are exactly two possibilities: this object either is either continuous with respect to this dimension, or it is bound with respect to this dimension. The difference between being bound and continuous with respect to a given dimensional region has to do with how an object is related to this region's sub-regions. Either the whole object occupies each of this region 's subregions, or else the whole object does not occupy each of its sub-regions, in which case the whole object occupies the whole region by partly occupying each of its sub-regions. An entity which occupies a region r (of space or time) by wholly existing in r' s sub-regions is said to be continuous with respect to this region, while an entity which occupies r by partly occupying r' s sub-regions is said to be bound with respect to this region (1970, 232). Returning to the second question of how an object 0 is related to its spatial and temporal boundaries, it turns out that there are exactly four possibilities: 0 is bound with respect to its spatial and temporal boundaries; (P I ) (P2) 0 is continuous with respect to its spatial and temporal boundaries; 0 is continuous with respect to its spatial boundary, and bound with . (P3) respect to its temporal boundary; and finally 0 is bound with respect to its spatial boundary, and continuous with (P4) respect to its temporal boundary . We are certainly most familiar with the final sort of object, which Zemach refers to as continuants in time, or more colloquially, as things or substances. This is surely because we think of ourselves as substances, since we think of ourselves as having spatial parts, but not temporal parts. We do no think of ourselves as having temporal parts because we think that we exist, in our entirety , at every moment of our existence. Someone who 1 I am making this point with respect to sets of divisions and objects to secure the possibility of being a realist with respect to some putative objects and a conventionalist with respect to others.

INTRODUCTION

3

saw me both yesterday and today saw exactly the same thing, and not distinct but qualitatively similar parts of the same thing. Or so we commonly think, though increasingly many philosophers are questioning this position. For our present purposes, the most important thing is to note, first, that we have a clear notion of what it would be for an object to be bound with respect to its spatial dimension, but not with respect to its temporal dimension, and second, (emphasizing the latter point) that we can conceive of an object's having a boundary on a given dimension without its having parts along that dimension. We are also fairly conversant with the first sort of spatiotemporal objects, which Zemach refers to as non-continuants, and more colloquially, as events. We certainly do think of such things as baptismal services and baseball games as having temporal parts. If I only witnessed the baptism itself, for example, you would not allow that I had seen the entire service, but only its most important part. And if you only happened to watch the first four innings of a baseball game, while I watched the last six, then we would surely agree to our having seen distinct but overlapping parts of the same game. It is also relatively easy to see that events must also have spatial (though certainly not organic) parts. Think, for example, of a certain battle, say, the Battle of Getteysburg. If we think of this battle at a certain moment of time, surely it is surely correct to think of it as having not merely a spatial location, but also a size, where its size is made up of distinct and possibly scattered or non-continuous spatial regions. The only alternative is to say that the whole battle is present, say, in a region where two men are feverishly engaged in hand-to-hand combat, and that seems obviously wrong. We are much less conversant with the second and third types of entities, perhaps because these objects are alike in having spatial boundaries without having spatial parts, and it is very hard to understand how this could be. That is, it is hard for us to see how a spatiotemporal object could be related to space in much the same way that we take ourselves to be related to time. But inasmuch as we have the general notion of an object's having a boundary along a given dimension without having parts along this dimension, we cannot easily dismiss these categories as contradictory or unintelligible. Zemach refers to the third type as continuants in space or processes. Metaphysically speaking, processes are the mirror opposites of substances: with respect to time, processes have parts while substances do not, and with respect to space, substances have parts while processes do not. Think, for example, of the digestion process. While it sounds right to think of this process as unfolding in temporal parts or stages (chewing, swallowing, and so on), and while this process, at any given time, certainly

4

CHAPTER ONE

has spatial boundaries, it seems wrong to speak of this process as having a size, or of consisting of distinct spatial parts. Of the four sorts of entities which Zemach discusses, the ones which he refers to as pure continuants or types are by far the strangest. Types are like substances in being continuous with respect to time, and they are like proce sses in being continuous with respect to space. In other words, types are spatiotemporal objects which lack both spatial and temporal parts. According to Zemach, the expressions "The letter A," "The American Woman, " ''The Taxpayer," and ''The Lion" all denote types. They are types precisely because they are capable of having multiple instance s: we can scribble instances of the first, I am married to an instance of the second, I happen to be an instance of the third, and I could conceivably be eaten by an instance of the fourth. But where I tend to think of types as abstract objects (which exist outside of space and time), on Zemach's view types are spatiotemporal objects, and hence material objects. In particular, they are "material objects ... recurrent both in space and time" (1970, 241). In order to make this clearer, let us focus on one such type, The Lion, and three of its instances: Alpha, Beta, and Gamma. Let us suppose , further, that Alpha lived from t1 to t3, that Beta lived from t4 to t6, and that Gamma lived from t7 to t9, so that the lives of these animals did not overlap. Now each of these lions, we think, is continuous with respect to time. Alpha, for example, exists in its entirety at every moment in time from t1 to t3. But we do not take these animal s to be continuous with respect to space. Consider the region of space which is occupied by Alpha ' s right paw at tz- Obviously this region of space does not contain the whole lion, but only part of one. Alpha , in other words, is bound with respect to space, and continuous with respect to time. Like particular lions, Zemach contend s that the type The Lion is continuous with respect to time. In connection with Alpha, for example, this type exists in its entirety-that is, it is entirely instantiatedfrom t1 to t3. There are two important differences between The Lion and particular lions, on Zemach's view. First, The Lion can exist, in its entirety, at successive, non-overlapping instances of time. Second, and more importantly, The Lion is continuous with respect to space, whereas particular lions are bound with respect to space. Consider the region of space which Alpha takes up at h- Now suppose that this region of space is evenly divided into 100 sub-regions. While Alpha is only partly present in each of these region s, Zemach contends that The Lion is wholly presentwholly instantiated-in each of them. I must confess that I have a very hard time accepting Zemach's treatment of types. Nevertheless, I do not feel that I am in a position to reject the possibility of objects which are continuous with respect to both space and time. After all, we have a perfectly clear understanding of spatio-temporal

INTRODUCTION

5

objects which are bound with respect to both space and time (events), and we also have clear understanding of what it means for an object to be continuous with respect to time (substances), and a reasonably clear understanding of what it means for an object to be continuous with respect to space (processes). But the fact that I have difficulty conceiving of such objects-particularly as types, which I take to be abstract objects-is beside the point. For all I know, there are indeed spatiotemporal objects which lack both spatial and temporal parts. Let me now explain, in general terms, why Zemach's paper is important for our present purposes. It is important, first, because it provides us with a systemic understanding of the radically different ways in which objects can be related to their spatiotemporal boundaries . And this, in turn, helps us to appreciate the fact that we are already committed to entities (such as events and processes) which are related their spatiotemporal boundaries in very different ways from how we take ourselves to be so related. Second, in addition to drawing our attention to these four very different ways in which an object can be related to its spatiotemporal boundaries, he shows that it possible to view each of them as the fundamental way in which the spatiotemporal world is divided up into particular objects. Thus, (a) an event ontology sees the world as being ultimately divided into spatiotemporal objects which have both spatial and temporal parts; (b) a type ontology sees the world as being ultimately divided into spatiotemporal objects which lack both spatial and temporal parts; (c) a process ontology sees the world as being ultimately divided into objects which have temporal parts but not spatial parts; and (d) a substance ontology sees the world as being ultimately divided into objects which have spatial parts but not temporal parts. While I suspect that most of us accept a mixed ontology-one which includes not just substances but also processes and events, if not also types-I think it must be acknowledged that we almost instinctively take substances to constitute the fundamental ingredients of reality, so that we explain the others sorts of entities in our ontology in terms of these. Thus, for example, while we are certainly willing to acknowledge the existence particular events (such as baseball games and baptismal services) and processes (such as reproduction and digestion), we aren't the least bit inclined to think of these entities as being on the same metaphysical level as baseball players and babies. Rather, we take substances or things to be primary, and we explain the other types of non-substantial entities in terms of what one or more substances do (events), what they are engaged in or undergo (processes), or how and what they are (types).

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CHAPTER ONE

We need to recognize, however, that our natural preference for an ontology of substances is a fact about us, and not about the world itself. And so we simply cannot afford to ignore the following question: (Q3) Of the four possible ontologies (substance, process, event, or type), which one, if any, best captures the nature of the cosmos and its fundamental ingredients? Zemach's answers to these questions represent an enormous departure what we might think of the popular, common sense view. In response to the third question, for example, he argues that each of these ontologies is fully adequate, and that there is literally nothing to recommend anyone of them over the others. Not only does he think that there no good reason for favoring one of these ontologies, having adopted a given ontology (say, for pragmatic reasons), he further insists that there is no single best way of chopping the world up into entities of the relevant sort. Thus, for example, he argues that given an ontology of events, there will always be many, equally legitimate ways of dividing up the spatiotemporal world into particular, medium-sized events, and he goes on to make similar points in connection with the other three ontologies. It is easy to see, then, that Zemach cannot embrace realism with respect to particular objects (in answer to the first question considered above), and that he must instead affirm some sort of conventionalist position. At least at first glance, Locke's answers to these questions appear to be comparatively tame. For starters, he has two basic ontological categories: he recognizes substances on the one hand, and modes on the other, with substances being "distinct particular things subsisting by themselves" (II.xii.6),2 and with modes being construed either as affections or actions of substances, or as our ideas of the these actions or affections.' Although he recognizes two ontological categories, if we were to ask him for a list of "things which exist" it would not include modes, but only particular substances which "subsist by themselves" . For he contends that there is nothing, in reality, which corresponds to our ideas of modes (Ilxxxi.3). We see a similar move in his treatment of general terms, where he denies the existence of anything in reality which corresponds to these terms, stating instead that "all things that exist are only particulars" (III.iii.6).4 In short, Unless otherwise noted, all quotations from Locke are taken from the Nidditch edition of his An Essay Concerning Human Understanding . Used by permission. 3 His initial account of modes (at II.xiiA) follows the latter characterization, which he acknowledges in this same section to represent a departure from the more traditional (Cartesian) account of modes, according to which the modes of an object are qualifications of its chief attribute, which is either thought (in the case of cogitative substances), or extension (in the case of corporeal substances). At any rate, Locke sometimes speaks of modes in exactly this way, e.g., at II.xxiii.30. 4 He makes a similar claim at Ill .iii.l . 2

INTRODUCTION

7

Locke contends that that individual substances are the only things which exist. But what sorts of entities does he recognize as substances? As we shall see in the ensuing chapters, he recognizes (a) simple (partless) incorporeal substances (God and finite spirits), (b) simple and complex corporeal substances (atoms, masses of atoms, artifacts , organisms), and (c) human persons, which on his view, are (probably) composed of both incorporeal substances and living corporeal substances. How would Locke have answered the first of the above questions? For his answer we must tum, first, to his distinction between single and collective substances (at II.xxiv.1 and II.xii.6). He cites particular men and sheep as examples of the former, and armies and flocks as examples of the latter. But he doesn't think that there really are such things as armies and flocks. There are, instead, only particular men and particular sheep. Our ideas of collective substances, on his view, are simply useful fictions. Or as he puts it, "they are but the artificial Draughts of the mind, bringing things very remote, and independent on one another, into one view, the better to contemplate, and discourse of them, united into one conception, and signified by one name" (II.xxiv.3). Second, amongst substances which are "constituted of pre-existing Particles, " he makes a distinction between those which are "produced in the ordinary course of Nature, by an internal Principle," and those whose cause "is extrinsical, and the Effect produced by a sensible Separation, or juxta Position of discernible Parts" (II.xxvi .2). The first, which he refers to as "natural things," are variously said to be generated or made by nature, while the second are said to be produced, fashioned, or made by us? In these passages I see no indication that Locke is inclined to think of artifacts as being ultimately unreal, or even as being less substantial than organisms . On the contrary, his considered opinion seems to be that watchmakers and gunsmiths do not merely rearrange pre-existing bodies, but that in so doing they succeed in bringing new corporeal substances into being. Let us return to the first question mentioned above. Does the world come to us "pre-sliced" into individual substances, or do we impose these divisions upon the world, in accordance with a system of concepts? From what we have seen thus far, it looks as if Locke is committed to the former, realist option, at least for large stretches of reality. It is hard to see how he could speak of organisms as individual substances made by nature without also taking the ontological divisions between these objects to be built into the fabric of the universe. But as we shall see in the ensuing chapters, this answer depends greatly upon how Locke answers the second of the above questions, which concerns the manner in which an object is related to its 5

See II.xxvi.2, III.vi.30, 36, and 40.

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CHAPTER ONE

spatial and temporal boundaries . The (preliminary) conclusion that Locke is a realist concerning particular objects depends upon the assumption that the atoms, masses, organisms and persons in Locke's ontology are bound with respect to space and continuous with respect to time. If, as I shall argue, Lockean "substances" are really more like Zemach's events-with both spatial and temporal parts-then Locke may well be committed to rejecting this realist position in favor of some form of conventionalism. For the time being, however , I shall proceed under the assumption that Locke embraces an ontology of substances, since that is how he has generally been interpreted. 2. Substances and their properties

As I have already suggested, we are naturally inclined to view the objects which surround us as substances in Zemach's sense, that is, as spatiotemporal objects which have spatial parts, but not temporal parts. But we don't merely think of these objects as persisting: we think of them as persisting through change. But what, precisely, do we mean by "change" in this context? Sometimes we use this word as synonymous with "replace," as when we speak of the changing of the guard, changing the oil (in an automobile), or changing a comma into a semicolon . In the present context, however, "change" is more nearly the opposite of "replace", since this sort of change requires continuity through time. In particular, it requires temporal continuity, and qualitative discontinuity: for starters, we can say that an object changes when, and only when, it has a property at one time, and the negation of this property at another. Clearly something more must be said about the need for qualitative discontinuity . Not just any sort of discontinuity will do: there are limits to the sorts of changes which a thing can undergo without ceasing to exist. There are limits, we believe, because some properties of a thing are more central to its existence than others. Philosophers have traditionally spoken of the former as essential properties, and of the latter as accidental properties . While there will frequently be disagreement about which of a object 's properties are essential or accidental, the distinction itself is not particularly controversial. For the sake of clarity, let us tum to particular example, say, my dog Lucky. Consider the following partial list of Lucky's present qualities : 1. Lucky is a mixed-breed lab. 2. Lucky is a neutered male. 3. Lucky has a black coat and a white patch on his chest. 4. Lucky is intensely fearful of explosive noises. 5. Lucky chased a squirrel this morning.

INTRODUCTION

9

How do we determine whether any of these properties belongs to Lucky essentially? It is sometimes suggested that an object has a property essentially if and only if this object cannot lose this property without ceasing to exist. But this cannot be right: the inability to lose a property without ceasing to exist is certainly a necessary condition for an object's having the property essentially, but it is not sufficient. Consider the final property on this list. Since the past cannot change, it isn't possible for Lucky to lose this property, which means, in tum, that he cannot lose it without ceasing to exist. And yet is seems obviously false to say that it is essential to Lucky to have chased a squirrel this morning. Why? Because we are confident that Lucky might not have chased a squirrel during this period of time. We are confident of this because we can easily imagine a set of circumstances in which he didn't chase a squirrel, say, one in which he didn't even notice any squirrels in the yard. Philosophers frequently speak of these different counterfactual circumstances as belonging to different possible worlds, where a possible world is a maximally complete, internally consistent account of how things might have been. While there is a good deal of controversy surrounding this talk of possible worlds," I submit that we already have an adequately clear notion of what possible worlds are all about. As evidence of this fact, consider the following counterfactual conditional: if Bill Clinton's parents had never met, then he wouldn't have been born. Most of us will agree that this statement is true, and that its truth is as unexceptionable as "Bill Clinton is a man." But while it is a relatively easy matter to assess the truth value of the latter statement, how are able to ascertain the truth value of the former? This requires, first, that we be able to consider various ways in which things might have been if his parents had never met. In addition, we must be in a position to "see" that some of these ways (= possible worlds) are more like the actual world than others, or as philosophers are fond of putting it, we must be in a position to see that some of these possible worlds are closer to the actual world than others. Whether we are aware of this or not, we take a counterfactual conditional to be true when and only when we take its consequent to be true in the closest world in which its antecedent is true, where the closest possible world will be the one which is most like the actual world, except for the fact that the antecedent is true in this world, and anything else which follows (logically or causally) as a result. While I am not claiming that we make these assessments self-consciously or in exactly these terms, I submit that short of considering these alternative possibilities, 6 The main debates appear to be (a) whether possible worlds are concrete particulars or abstract objects of some sort, and (b) how individuals in the actual world are related to individuals in possible worlds. We will return to these debates in the final chapter of the

book.

10

CHAPfERONE

and of comparing their relative closeness to the actual world, one would simply not be in a position to understand these statements, much less to assess their truth value. Using this notion of possible worlds, it is an easy matter to give a more satisfactory account of the accidental/essential property distinction. Let us assume, for the moment, that it is possible for a single individual to exist in various possible worlds. Take Richard Nixon, for example. How can possible-world-talk help us to understand Nixon's modal properties? For starters , Nixon is a contingent being, which means that he might not have existed; in the language of possible worlds, this means that he exists in some possible worlds, but not in others . Similarly, to say that Nixon has a property essentially is to say that-metaphysically speaking-he couldn't have lacked this property, or (equivalently, in the language of possible worlds) that he has the property in every possible world in which he exists . Conversely, to say that he has a property accidentally is to say that he might not have had it, or (equivalently) that he has this property in some worlds, but not in others. And so to say that it is not the case that Nixon might have been a cockatrice is to say that there is no possible world in which he is a cockatrice; and to say that Nixon might have been a Democrat is to say that there is a possible world in which he (the very same person) is a Democrat. Given this account of the accidental/essential property distinction, we are in a position to confront yet another difficult but important question : (Q4) For any object 0 and any of its putatively essential (accidental) properties F, is it an objective, mind-independent fact that 0 is essentially (accidentally) F, or is O's being essentially (accidentally) F a matter of convention? Suppose we can agree that Socrates is essentially rational. We must then ask what makes this true: is it true in virtue of some objective feature of the universe, or is its truth a matter of convention? Or perhaps better, is Socrates' being essentially rational a fact about Socrates himself, or is it rather a fact about what we have decided to include in the concept Man? We shall return to this question shortly. 3. Essential properties and natural kinds It is important to point out that it has only recently become common to use possible world semantics to explain the accidental/essential property distinction. The more traditional approach-which is rooted in Aristotle-is to take an object' s essential properties to be determined by the infima (i.e., lowest) species to which this thing belongs, where Lucky is associated with the infima species Dog, and Socrates is associated with the infima species Man, while both share equally in such "higher" species as Mammal, Animal

INTRODUCTION

11

and Organism. On this view, an object' s essential properties will be contained in the definition of its infima specie s. There is one important respect in which Locke ' s thinking about essences is aligned with this Aristotelian tradition: he thinks that it makes no sense at all to speak of an object as being essentially F independently of a given kind or species term. If we consider an object in abstraction from any given species, he thinks, then any thought of its having a property essentially "instantly vanishe s" (III.viA). It is indeed difficult to take issue with this claim. Suppose that I have placed a large box in front of you, with the understanding that this box contain s an object, which we'll call "Fred". Suppose, in addition , that the only thing you know about Fred is that Fred 's internal temperature is below freezing, and that Fred is partly composed of carbon atoms. And now suppose I ask you to tell me whether Fred has either of these properties essentially. It is pretty obvious, I think, that short of knowing what sort of thing Fred is, you cannot even begin to answer this question. You cannot even begin to deliberate, for example, upon whether there is a possible world in which Fred is not partly composed of carbon atoms. Given this connection between essential properties and kinds, in order to get clearer on the sort of essentialism which Locke is objecting to we need to confront yet another question. While it is obviously the case that we sort naturally occurring objects (organisms and portions of chemical stuff) into kinds or species , we must still consider the metaphysical status of these categories: (Q5) Is there an ontologically privileged way of sorting particular objects and portions of matter into (lowest) kind s, or is there, instead, a plurality of equally legitimate ways of sorting them into kinds? As with the first question, it seems that one can either be realist or a conventionalist about the existence of "natural kinds," where the realist affirms and the conventionalist denies that naturally occurring objects are sorted into (lowest) kinds by nature, so that our goal, as taxonomists, is to correctly identify these natural divisions between groups of individuals. It is here, it seems to me, that Locke and Aristotle part ways: Aristotle embraces a realist position with respect to kinds, while Locke embraces a conventionalist position . Although both men would agree that the we can only attribute essential properties to objects relative to a given species, Aristotle maintains that it is an objective, mind-independent fact about Socrates that he is a member of the species Man, which means (since rationality is objectively contained in the definition of this species) that it is also an objective modal fact about Socrates that he is essentially rational. Thus for Aristotle, his being essentially rational is a matter of discovery, and not a matter of decision.

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For reasons which will become clearer in the upcoming chapter, Locke denies the existence of objective, naturally occurring specie s. On his view, there is a plurality of equally legitimate ways of sorting things into kinds, which means, in the case of Socrates and manhood, that there is no such thing as the correct account of what it is to be a man. And so, for example, some conceptions of manhood will include the concept of rationality, and other, equally legitimate concepts will not. And this means, in tum , that Socrates will be con sidered essentially rational relative to some notions of manhood, and accidentally rational relative to other, equally legitimate notions. We have here a picture both of Aristotelian essentialism and Lockean anti-essentialism. Although both seem to realists about naturally occurring objects, and while both agree that questions about the essences of particulars are conceptually connected to questions about kinds, Aristotle's essentialism is grounded in his realism with respect to kinds, and Locke's rejection of essentialism is grounded in his conventionalism with respect to kinds . Even at this point, it seems to me that there is a sort of tension in Locke's position which is not present in Aristotle's. That is, it is hard to see how he can be a realist about individual substances, but not about the kinds which they instantiate, since this means that he is a realist about particular substances, but not about their essential properties, and in particular, the properties which are necessary for their continued existence. As I shall try to illustrate in what remains of this chapter, this tension is also present, in a heightened manner, in his theory of identity. II. IDENTITY AND PERSISTENCE

1. Identity The second major topic of this book is that of identity or sameness. In particular, we will be concerned with the relation of numerical identity. As the word "numerical" suggests, to say that an object A is identical with an object B is to say that A and B are one and the same thing, as when we say that Mark Twain is (identical with) Samuel Clemens, or that George Eliot is Mary Ann Evans . Before I say more about the precise nature of this relation, it will be helpful to observe a few distinctions. We must distinguish, first, between the relation of identity and its relata, that is, the "things" which are said to be so related; and second, between this relation and statements which affirm instances of this relation. These statements typically fall into one of two categories: synchronic identity-statements take this relation to hold between an object and an object at a single time, and

INTRODUCTION

13

diachronic identity-statements take this relation to hold between an object at one time and an object at another time.' Finally, we must distinguish between the relation of numerical identity, which by definition cannot obtain between distinct objects, and the relation of qualitative identity, which can . We speak of numerically distinct objects as being identical in the latter sense when they sufficiently similar in certain relevant respects, as when we speak of a reprint of a photograph as identical with the original. It is sometimes suggested that qualitati ve identity is necessary for numerical identity, but this is a mistake. If qualitative identity were necessary for numerical identity, then nothing could undergo change, since an object can change only if it exists at different time s with different properties. Although there is obviously a good deal more to be said about the nature of this relation, most anything one can say will be controversial. Perhaps the best way to illustrate this point is to briefly survey some of the current debates on this topic. I will subsequently attempt to develop Locke 's theory of identity in terms of these debates. One such debate is concerned with whether identity is a simple, primitive, unanalyzable relation, or whether it is reducible to still more basic relations and properties. Similar debates have been waged in the fields of ethics and epistemology. In the case of ethic s, for example, G. E. Moore has argued that evaluative concepts such as goodness are simple and hence cannot be defined in terms of non-evaluative concepts, while others (hedonistic utilitarians) have argued that this concept can be defined in terms of pleasure, and still others (divine command theorists) have argued that it can be defined in terms of what God has commanded. In the case of epistemology, some have argued that the epistemic knowledge relation ("_ knows that _") is a primitive, unanalyzable relation, since knowledge con sists in a direct awareness of the facts themselves, while others have argued that this relation is not primitive, since knowledge-statements of the form "S knows that p" are reducible to (at least) (i) S believes that p, (ii) S is ju stified in believing that p, and (iii) p is true. Most philosophical work on the topic of identity has been focused upon issues related to diachronic identity-statements, and in particular, upon diachronic identity-statements concerning persons. In these terms, the present debate turn s upon the following question: (Q6) Is it possible to give informative and non-trivial necessary and sufficient truth conditions for statements of the form "Person A at t) is identical with Person B at t2"?

In the final chapter of the book we will also consider a third sort of identity-statement, that is, those which state that this relation holds between an object in one set of circumstances and an object in different counterfactual circumstances (possible worlds) .

7

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CHAPTER ONE

While some philosophers have argued that statements of personal identity are brute, unanalyzable facts," most philosophers have followed Locke in arguing that truths about personal identity "consist in" or are reducible to other sorts of facts or conditions." And of those who allow for a reductive analysis of such statements, most have once again followed Locke in taking personal identity across time to be a function of psychological continuity between conscious subjects at successi ve instances," while others insist that physiological continuity is what matters, and still others insist upon both sorts of continuity. I would like to make two additional points in connection with this first debate. First, Locke's analysis of personal identity in terms of continuity of consciousness is a function of his account of what a person is, together with his principle that identity must be "suited to the idea," that is, that the identity conditions for a particular object are determined by the idea which we associate with this object." Second, prior to using this principle to generate this account of identity in the case of persons, he had already used it to generate similar accounts in the cases atoms, masses of atoms, and organisms. The next two debates can be considered together. The first is concerned with the appropriate terms of this relation, and in particular, with whether identity-statements must be made relative to some sortal concept. The debate here turns upon the following question: (Q7) Is the relation of identity a dyadic (two-place) relation which holds (simply) between an object and an object, or is it a tryadic relation which holds between an object, and object, and a concept? The issue here is whether an identity-statement such as "George Eliot is Mary Ann Evans" is well-formed. Those who take identity to be a dyadic relation argue that it is, while those who take identity to be a tryadic relation argue that a complete and well-formed version of this statement would be something like "George Eliot is the same Person as Mary Ann Evans". Here is where the third debate comes in. Compare this last statement with "George Eliot is the same Human Being as Mary Ann Evans." While these are obviously different statements, there is a question as to whether they have different truth-conditions. Could just one of these statements be true? More generally, Early proponents of this view include Thomas Reid and Bishop Butler. More recently, this view has been defended by Elias Savellos (1990), Michael Jubian (1996), and Ken Akiba (2000). 9 See Jubian (1996, 344). 10 See Trenton Merricks (1999, 984). II See 1I.xxvii.7-9. The phrase "identity suited to the idea" occurs in his footnoted subtitle to ILxxvii.7.

8

INTRODUCTION

(Q9)

15

Is it possible for an object A and an object B to be the same F, but different G's? To put this question into more familiar terms, suppose that we have before us an old man who, like the rest of us, thinks that he was once only a year old, though he has no conscious memory of being so young. Let "Little Joe" stand for this one-year-old boy, and let "Big Joe" stand for this old man. Since each is both a person and human being, we are in a position to ask whether Little Joe and Big Joe are the same human being, but different persons. It is not hard to see why Locke might have been tempted to give an affirmative answer to this question, inasmuch as he thinks that continuity of consciousness-in terms of memory-is necessary and sufficient for personal identity, and that continuity of life is necessary and sufficient for animal (and hence human) identity. The present debate hinges upon competing conceptions of identity. Those who insist upon a negative answer to the above question affirm what has come to be known as an absolute conception of identity, while those who insist upon a positive answer to this question affirm a relativistic conception of identity. Let's begin with some formal features of the absolute conception. The relation of identity, on this view, is reflexive, symmetrical, and transitive. A reflexive relation is one which holds only between a thing and itself. Thus reflexive relations are to be contrasted with irreflexive relations (such as the " _ is a brother of _ " relation) which never hold of a thing and itself, and non-reflexive relations (such as the " _ loves _ " relation), which can hold both of distinct things and of a thing and itself. A symmetrical relation is one which, for any object x and any object y, if x bears this relation to y, then y also bears this relation to x. As before, symmetrical relations are to be contrasted with asymmetrical relations (such as the " _ is a larger number than_" relation), whose instances never exhibit this sort of symmetry, and non-symmetrical relation (like the " _ is the brother of _ " relation), some of whose instances exhibit this symmetry, while others do not. Finally, a transitive relation is one which, for any object x, any object y, and any object z, if x bears this relation to y, and y bears this relation to z, then x bears this relation to z. Transitive relations are to be contrasted with intransitive relations (such as the " _ is twice as large as _ " relation, whose instances never exhibit transitivity, and non-transitive relations (such as the " _ loves _ " relation), which have instances which exhibit transitivity and those which do not. How does a relativistic conception of identity differ from the absolute conception? The most important difference, I take it, is that the former must be characterized as non-transitive. In order to see why, let us return to the example of Little Joe and Big Joe. Let us suppose that our relative identity

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theorist thinks that Little Joe and Big Joe are the same human being, but different person s, since he thinks, with Locke, that continuity of consciousness is necessary and sufficient of personal identity, and that continuity of life is necessary and sufficient for animal (and hence human) identity. Big Joe is not the same person as Little Joe because he cannot remember being, as it were, in Little Joe's shoes. But suppose that there is an intermediary "Joe"---call him "Middle Joe"-who can remember being in Little Joe's shoes, and that the same is true of Big Joe in relation to Middle Joe. Under these circumstances, the relative identity theorist will have to say both that (a) Little Joe is the same person as Middle Joe, and (b) Middle Joe is the same person as Big Joe, even though (c) Little Joe is not the same person as Big Joe. This shows that the relative identity relation is not transitive. Since instances of this relation will sometimes exhibit transitivity, we must conclude that the relative identity relation is nontransitive. The final debate I would like to mention here is concerned with whether identity is a topic-neutral relation. Consider the relation of identity which obtains , say, between a calf at tl and a heifer at tz. and also the relation of identity which obtains between a foal at t) and a mare at t2. Now consider the following question: are these instances of the very same identity relation, or are there as many kinds of identities as there are kinds of things ? More generally, we are asking the following question: (QI0) Do identity-statements of the form "that F at t l is this Fat t2" and "that G at t l is this G at t2" involve distinct instances of the same identity-relation, or distinct instances of distinct identity-relations which bear an obvious "family resemblance"? Those who contend that identity is a topic-neutral relation affirm the first possibility, while those who deny that identity is a topic-neutral relation affirm the latter. With Michael Jubien (1996, 348), I have a hard time believing that identity-statements concerning cows on the one hand and horses on the other involve instances of different identity-relations. At least at first glance, the highly abstract nature of this debate makes it hard to see why it even matters, much less how one might begin to evaluate the relative merits of the opposing positions. At any rate, I am confident that Locke did not think about identity in this way. He begins his now famous chapter on identity, "Of Identity and Diversity," by setting forth a general account of identity which is grounded in his principle of individuation, which he takes to be "existence itselt". " As we shall see in more detail in Chapter Three, 12 As I shall explain in Chapter Three, this chapter was added to the second edition of the Essay in response to the suggestion that he discuss the "much sought after" principle of individuation.

INTRODUCTION

17

in §§ 1-2 of this chapter he contends that objects are individuated-that is, set apart as individuals (of a given kind) from all other individuals-by the time and place at which they first came into existence. He subsequently takes this account of individuation to yield a general, universally applicable account of identity-across-time. Thus, after concluding that, for each naturally occurring object, there is a single time and place at which this object came into existence, he concludes § 1 in the following manner: That therefore that had one beginning is the same thing, and that which had a different beginning in time and place from that, is not the same but divers. That which has made the Difficulty about this Relation, has been the little care and attention used in having precise Notions of the things to which it is attributed. (328) Since it is not clear from this passage that he is particularly concerned with the issue of identity-across-time, note how he applies this account of identity to the case of finite spirits in the next paragraph: Finite spirits having had each its determinate time and place of beginning to exist, the relation to that time and place will always determine to each of them its Identity as long as it exists. (329) Taken together, these passages indicate that he has general conception of identity which is applicable-by way of his idea principle-to all spatiotemporal realities. Although he does speak of various "sorts of identity" on one occasion, and while he frequently speaks of "personal identity.t'" I take this talk of "kinds of identity" to be a facon-de-parler. Thus, for example, I take his use of the expression "personal identity" to be a reference, not to the unique kind of identity which is applicable to persons, but rather to cases in which the relation of identity is applied to specific persons. Suppose that I am right in taking Locke to have a topic-neutral conception of identity. Does anything interesting follow from this fact, particularly in connection with the previously considered debates on this topic? Michael Jubien has recently argued that accepting this conception of identity commits one both (a) to the thesis that identity is a simple, unanalyzable relation, and (b) to the thesis that we cannot give informative, non-circular truth conditions for identity-statements (1996, 348). But as we have already seen, Locke thinks that in some cases we can give informative truth conditions for diachronic identity-statements, and indeed he has a general formal for doing just this: the identity-conditions which we assign to a object are determined by the idea which we associate with this object. 13 He speaks of "sorts of identity" at I1.xxvii.7, and of "personal identity" at II.I.lI and in most of the later sections of ll.xxvii (§§7-14, 18, 19,21,23, and 25).

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What more can Locke say to Jubien? For starters, he must insist that although the relation of identity which obtains between an atom at one time and an atom at another time is the same relation which obtains between a foal and a mare, the conditions under which this relation obtains in these instances differ widely. And so he argues in §7 of his identity chapter that it is not "Unity of Substance that comprehends all sorts of Identity, or will determine it in every Case." He is saying, in other words, that sometimes identity-across-time is a function of sameness of constituent substances, and sometimes it is not. In particular, he thinks that identity consists in sameness of constituent substance in the case of atoms, masses of atoms, and spirits . In the case of organisms and persons, however, he thinks that identity consists in "something else," namely, continuity of life in the case of organisms, and continuity of consciousness in the case of persons . In partial agreement with Jubien, I think that Locke must admit that he has failed to give an informative and non-circular account of identity for objects whose identity consists in sameness of constituent substance. As evidence of this, look again at his account of identity in the case of finite spirits: Finite spirits having had each its determinate time and place of beginning to exist, the relation to that time and place will always determine to each of them its Identity as long as it exists. (329)

He is saying here, in essence, that each finite spirit will continue to exist "as long as it exists" (emphasis added), and this is hardly illuminating. In §3 he says the same thing in connection with atoms and masses . Speaking first of an atoms, he writes, being, at that instant, what it is, and nothing else, it is the same, and so must continue, as long as its Existence is continued: for so long it will be the same, and no other. In like manner, if two or more Atoms be joined together into the same Mass, every one of those Atoms will be the same, by the forgoing Rule: And whilst they exist united together, the Mass, consisting of the same Atoms, must be the same Mass, or the same Body. (330)

In the case of organisms and persons, however, I think that Locke has succeeded in giving a reductive account of identity-across-time: claims about sameness of organisms have been reduced to claims about sameness of certain biological processes, and claims about sameness of persons have been reduced to claims about sameness of certain mental processes. Against Jubien, I don't see any reason for thinking that he cannot, at the same time, insist that identity is a topic neutral relation in these cases, just as it is in the case of atoms, masses, and finite spirits.

INTRODUCTION

19

As we shall see in more detail in Chapter Three, William Uzgalis has taken Locke's commitment to a topic-neutral conception of identity to have a different sort of implication. According to Uzgalis, Locke' s implicit acceptance of a topic-neutral conception of identity is indicative of his rejection of the relative identity thesis, the thesis, once more, that it is possible for an object A and an object B to the same F, but different G's (1990, 284). Unfortunately, this argument depends upon the premise that the relative identity theorist must reject a topic-neutral conception of identity, and this is a mistake. While the relative identity theorist must admit that identity is a tryadic relation, he does not have to admit that identity-statements for different kinds of entities involve different relations, but only different relata, inasmuch as this relation holds between an object, an object, and a concept. For what it's worth, I think that Locke does take this identity to be a tryadic relation. In practice, at least, whenever he makes or considers identity-statements between objects, these statements are always made relative to a sortal concept. I should add, however, that his (implicit) affirmation of the thesis that identity statements must be made relative to a sortal concept does not commit him to the stronger thesis that objects can be identical relative to one and distinct relative to another. While we are on the topic, let me briefly explain why I think Locke does not accept the relative identity thesis. Consider his statement in §3, for example, that a seedling and a mature tree "are... not the same Masses of Matter, though they be truly ...the same Oak." On the relative identity interpretation, Locke is understood as saying that the seedling and the mature tree are identical with respect to one sortal (Oak), but not with respect to another (Mass of Matter). In particular, he is taken to be saying both (i) that the seedling is an Oak, the mature tree is an Oak, and the seedling is the same Oak as the mature tree, and (ii) the seedling is a Mass of Matter, the mature tree is a Mass of matter, but the seedling is not the same Mass as the mature tree. While I think he would agree that the seedling and the mature tree are the same Oak, he would not admit that either the seedling or the mature tree is identical with a mass of matter. For take any organism 0 and any of its constituent masses of matter m. Either m is o's first constituent mass, or it isn't. If it is not, then m and 0 came into existence at different times, which on Locke's principle of individuation precludes m from being o. If m is 0' s first constituent mass, then although they presumably did come into existence at the same time, there will certainly be a later time at which 0 exists even though m does not. And this conflicts which Locke's wider understanding of his principle of individuation, according to which each object is differentiated from every other by its location at every moment of its existence. And so either way, the relative identity interpretation is incompatible with Locke's principle of

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individuation. Since his main reason for writing the identity chapter is to elaborate upon his principle of individuation, it is unlikely that he would have developed his theory of identity in a way that is clearly incompatible with this principle. Developing Locke's positions with respect to these recent debates on the topic of identity has yielded a more-or-less complete summary of his theory of identity. Before I develop what I take to be the fundamental problem of the book-namely, that of determining whether his theory of identity is compatible with his rejection of essentialism-I would like to briefly discuss some related debates on the topic of persistence. 2. Persistence

What does it mean to say that an object persists? In general, we can say that an object persists just in case it exists continuously through successive instances of time. It is not hard to see that questions about identity-acrosstime can often be more simply phrased in terms of persistence. Suppose, for example, that we want to ask whether it is ever the case that an object with one set of properties at t1 is identical with an object with a different set of properties at t2. This question, in terms of persistence, becomes the following: (QII) Do any objects persist through change? I suspect that very few people will be able to take this question seriously, for the simple reason that we cannot but think of ourselves as persisting beings. The evidential force of memory seems to be psychologically irresistible. And though we lack this sort of evidence in other sorts of cases, we are just as sure that other persons persist, and we are only slightly less inclined to think of our pets, our computers, and our cars as persisting beings. Nevertheless, it must be said that these are primarily facts about how we think, and not about how the world is. And while the evidential force of memory is certainly psychologically irresistible, it is not logically conclusive. Thus, for example, it is possible that we haven't existed for more than an instant, and that what we take to be memories of our existence in the past are only pseudo-memories which give rise to the false appearance of a past existence. Moreover, in the absence of this sort of first-person evidence, it is easier to make this sort of claim with regard to other persons, and easier still to say this in connection with the organisms and artifacts which surround us. On the assumption that things do persist, we are naturally led to inquire after the conditions under a given object persists, and this leads to us back the topics of kinds and essences. For in identifying an object's persistence conditions, we will have identified the properties which it can and cannot

INTRODUCTION

21

lose without ceasing to exist, which means that we will have begun to distinguish between its accidental and essential properties. And as we saw earlier, we can only make this distinction for an object which has been identified as an object of a given kind. Before we pursue this topic further, however, we must address a debate which I take to be even more fundamental, a debate concerning the manner in which thing persist. For the moment, at least, let us restrict our attention to the spatially extended objects which surround us: organisms, persons, and artifacts. I trust that we are correct in thinking of these as persisting beings, but more needs to be said about how these objects succeed in existing at successive instances. As it turns out, there are exactly two possibilities . These objects either persist by enduring through time, or they persist by perduring through time, where an enduring object is one which exists in its entirety at each successive moment of its existence, and a perduring object is one which exists different times by having different temporal parts at these times. It might be helpful to put this distinction in terms of Zemach's terminology, developed above. We all take organisms, artifacts and persons to have both a spatial dimension (as physical objects) and a temporal dimension (as persisting objects). We also take these objects to be bound with respect to space, since we take them to exist in different places at the same time (the desk at which I am presently sitting, for example, exists both to my immediate left and my immediate right) in virtue of their having distinct spatial parts in these places. This debate concerning persistence, then, turns upon how these objects are related to their temporal dimension, and in particular, to whether they bound or continuous with respect to this dimension. An object which persists by enduring through time is continuous with respect to time, while an object which perdures through time is bound with respect to time. Thus, a perduring physical object is related to time in a manner which is strongly analogous its relation to space: it exists at different times in virtue of its having different temporal parts at these times, just as it exists at different places (at a give time) by having different spatial parts in these places. Following contemporary usage, I shall sometimes speak of objects which persist by enduring as three-dimensional objects, and of objects which persist by perduring as four-dimens ional objects. Although we can speak of both sorts of objects as persisting, we need to be clear about the differences involved in giving persistence conditions in these two cases. On the one hand, giving persistence conditions for a three-dimensional object involves stating the conditions under which this object can continue to endure through time, that is, the conditions under which the very same thing can exist, in its entirety, from one time to another. Giving persistence conditionals for a four-dimensional object, on the other hand, involves

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stating the conditions under which numerically distinct , successively existing objects can be (temporal) parts of the same, temporally extended object. Although I shall continue to speak about persistence conditions, in general terms, I shall also refer to persistence conditions for enduring object as endurance conditions, and of persistence conditions for perduring objects as perdurance conditions. The spatially extended objects in Locke 's ontology include (at least) atoms, masses of atoms, organism s and persons. Although he gives persistence conditions for each of these objects , he does not give an explicit account of the manner in which these objects persist. Thus, for example, while he gives a detailed account of the conditions under which organisms and persons can continue to exist, but he never addresses the question of the manner in which they exist at different times. And as I shall argue in more detail in Chapter Five, this omission is not due to fact that he lacked any conception of a temporally extended object, since it is pretty clear that he did have such a conception. Although he does not address the question of whether objects persist by enduring or by having temporal extent, we can still ask whether he is logically committed to one of these accounts by what he does explicitly say. And in connection with this question, I should add that Locke 's commentators have almost universally argued or (more commonly) assumed that the physical objects in his ontology persist by enduring through time." In other words, they have taken him to be giving endurance conditions for particular objects, and in particular, for atoms, masses, organisms , and persons. For the sake of argument, let us assume that they are right. I will now explain why Locke 's theory of identity, on this reading, is either internally inconsistent or incompatible with his rejection of essentiali sm. 3. Identity, persistence, and Lockean anti-e ssentialism As we saw in connection with his critique of essentialism, Locke appears to be a realist about naturally occurring objects (atoms, masses, and organisms), although he is not a realist about the kinds which these objects instantiate. That is, he thinks, on the one hand, that particular living and non-living bodies exist-as discrete individuals-independently of our beliefs, desires, and classificatory decisions. On the other hand, he does not believe that there is a single best way of sorting these objects into kinds or species, since he denie s that things are sorted "by nature" into objective, mind-independent species. He thinks , instead, that we sort things into species, and that we do so in a manner which is largely determined by our

14

I will give a detail ed defense of thi s thesis in Chapter Five.

INTRODUCTION

23

particular experiences, resources, and objectives. And this means, in practice, that there will be a plurality of equally legitimate ways of sorting living and non-living bodies into lowest species. In addition, he contends that an object can only have essential properties relative to a given species, since we cannot intelligibly speak of an object as being essentially F per se. Taken together, these positions imply that the properties which are essential to an object relative to one lowest species and one system of classification will not be essential to this object relative to other species concepts and systems of classification. And this means that Locke is in the awkward position of being a realist about naturally occurring objects, but not about the properties which are essential to their existence. I contend that the tension which is present in his rejection of essentialism is not resolved by his theory of identity, but is instead magnified to the point of contradiction. In order to see why, we need only to examine the manner in which the two sources of this tension (his realism about particulars and his relativism about kinds and essences) are present in this theory. His realism about particulars is clearly expressed in his principle of individuation, which states that objects are individuated-that is, set apart as discrete individuals-by the time and place in which they first came into existence, and, by implication, by their location at every successive moment of their existence. Indeed , this principle effectively extends this realism from a realism about what objectively exists at a given moment, to a realism about the objective temporal boundaries ofthese existents. It is not hard to see that his theory of identity accommodates and even extends his relativism with respect to kinds and essences . In the first place, there is his principle that the persistence conditions which we give for a particular object are determined by the infima species concept which we associate with this object. In the second place, there is his allowance that a given object may be associated with a plurality of such sortal concepts, that is, concepts which are at once empirically adequate and non-trivially different. 15 With the addition of this latter point, his relativism about kinds and essences is extended to a relativism about the persistence conditions for particular objects. Suppose, for example, that you and I have very different (but empirically adequate) concepts of what it is to be a cat. As we apply Locke's idea principle, this will mean that the persistence conditions which I associate with Tabby will be different from the ones which you associate with her, and if Locke is right, it makes absolutely no sense to ask whether either of us is giving the correct set of persistence conditions for Tabby. On his view, there is simply no fact of the matter.

15 See, for example, §§15 (340: 18-27) and 28 (348:7-10) of his identity chapter. I will defend this claim in more detail in Chapter Three .

24

CHAPTER ONE

It thus appears that Locke has a full-blown contradiction on his hands : he cannot consistently be both a realist about the temporal boundaries of a given object and a relativist about the conditions under which it persists. As I shall argue in more detail at the end of Chapter Three , Locke is confronted with a seemingly intractable dilemma. In his identity chapter he gives us persistence conditions for particular atoms, masses, organisms, and persons. In particular, we are taking him to be giving us endurance conditions for particular objects. In the process , he is either giving us absolute persistence conditions for particular objects (that is, conditions under which an object ceases to exist, absolutely), or he is giving us relative endurance conditions for these objects (that is, the conditions under which an object ceases to exist, not absolutely, but only qua F or G). But either way, he faces a contradiction. He cannot give absolute endurance conditions without contradicting his anti-essentialism, since he cannot say, for example, that Tabby absolutely ceases to exist if she ceases to F without saying that F-ness is essential to Tabby-the thing itself-and not merely qua Cat. And he cannot give relative endurance conditions for particular objects without contradicting his principle of individuation, since this would commit him to denying the thesis that objects have objective temporal boundaries, and in particular, an objective initial boundary. 4. A brief look ahead

Although it certainly looks as if Locke's theory of identity is incompatible with his rejection of essentialism, the final three chapters of this book constitute a sustained argument to the contrary. This argument falls into two parts : I argue, first, that the physical objects in Locke's ontology do not persist by enduring through time, but rather by perduring through time, and second, that his theory of identity, when applied to fourdimensional objects, is internally consistent and logically compatible with his rejection of essentialism. In Chapters Four and Five I present three lines of argument for the thesis that the spatially extended objects in Locke's ontology also have a fourth, temporal extent. The first stems from his account of persistence for organisms and persons, the second stems from his isomorphic treatment of space and time, and the third stems from the theory of creation which received from Newton . Finally, in Chapter Six I explain why Locke avoids the above dilemma on a four-dimensional ontology. In general terms, this ontology enables him to give a relativistic account of persistence-in accordance with his relativism with respect to kinds and essences-without being committed to a relativistic account of identity, and hence without running afoul of his principle of individuation.

2

LOCKE'S CRITIQUE OF ESSENTIALISM

Let us return, briefly, to three questions from the previous chapter: (Ql) Does the cosmos already come to us divided up into particular objects, or are these divisions something which we impose upon the world , in accordance with some sort of a "conceptual scheme"? For any object 0 and any of its putatively essential (accidental) (Q4) properties F, is it an objective, mind-independent fact that 0 is essentially (accidentally) F, or is O's being essentially (accidentally) F a matter of convention? (Q5) Is there an ontologically privileged way of sorting these objects into (lowest) kinds, or is there , instead, a plurality of equally legitimate ways of sorting them into kinds? As I have already begun to argue, Locke gives a realist answer to the first question, and a conventionalist answer to the second, which forces him, in tum, to give a conventionalist answer to the third. Although he allows that nature comes to us divided up into particular objects, he does not think that these objects are further divided, by nature, into objectively existing kinds or species. Rather, he insists that it is we who sort these objects into kinds or species, and that we do so in a manner which is arbitrarily determined by our particular experiences, interests, and objectives. Since he thinks that there will be many, equally legitimate ways of sorting objects into kinds , and since he also thinks that we cannot intelligibly speak of an object as having essential properties apart from these decisions, he concludes that the properties which are essential to an object on one system of classification will not be essential to it on other, equally legitimate systems. And this , I take it, is essence of his anti-essentialism. In this chapter I will develop these points in much greater detail. In Part One I develop his contention that naturally occurring objects can have essential properties only relative to a given kind or species. In Part Two I discuss his rejection of the thesis that nature itself sorts these objects into objectively existing kinds or species. And in Part Three I present his positive views about the classification of corporeal substances, and why he takes the results of this process to be largely determined by human interests, activities, and conventions. 25 C. H. Conn (ed.), Locke On Essence and Identity © Kluwer Academic Publishers 2004

26

CHAPTER TWO

I. LOCKE ON THE ACCIDENTAUESSENTIAL PROPERTY DISTINCTION

1. The sortal relativity of essential properties

Locke contends that particular objects do not have essential properties per se, but only as members of a sort or kind: That Essence, in the ordinary use of the word, relates to Sorts , and that it is considered in particular Beings, no farther than as they are ranked into Sorts, appears from hence: That take but away the abstract Ideas , by which we sort individuals, and rank them into common names, and then the thought of anything essential to any of them, instantly vanishes: we have no notion of the one, without the other: which plainly shews their relation. (Ill. viA)

Thus, Locke continues, nothing is essential "to any Individual whatsoever, till the mind refers it to some sort or Species of things; and then presently, according to the abstract Idea of that sort, something is found essential." He contends, therefore, that an object which is being considered apart from any species does not have any essential properties: If it be asked, whether it be essential to me, or any other particular corporeal Being to have Reason? I say no; no more than it is essential to this white thing I write on, to have words in it. But if that particular Being, be to be counted of the sort Man , and to have the name Man given it, then Reason is essential to it, supposing Reason to be a part of the complex Idea the name Man stands for: as it is essential to this thing I write on, to contain words, if I will give it the name Treatise, and rank it under that Species. (III.vi A)

In this and other passages Locke purports to refer to particular objects independently of their falling under any sortal concepts. Following David Owen (1991), I shall refer to these objects as "unsorted particulars". In keeping with his realist answer to QI, he does not endorse the now widely held view that objects can only be identified as objects of a particular kind. In III.vi.4, for example, he refers to himself, in the first person, apart from his being ranked under the sortal Man. Later in the same section he refers to another unsorted particular, namely, "the white thing I write on", apart from its being ranked under the sortal Treatise, and in the subsequent section he refers to "the particular parcel of matter I cut my pen with" apart from its being ranked under the sortal Iron. These passages reveal an additional feature of Locke's treatment of unsorted particulars : he also thinks that we can speak truthfully about their various qualities. He allows, for example, that the thing which he is writing

LOCKE'S CRITIQUE OF ESSENTIALISM

27

on is white, apart from its being called a treatise , and that he has reason, as well as a particular color and shape, apart from his being called a man. He continues to insist, however, that we should not take any of the qualities of an unsorted particular to belong to it essentially. Thus he writes that it would be "very improper and insignificant to ask, Whether it be essential to the particular parcel of Matter I cut my Pen with, without considering it under the name Iron, or as being of a certain Species "(llI. vi.5). In addition to discussing the manifest qualities of an unsorted particular, Locke also discusses the corpuscularian microstructure which gives rise to these qualities. In III.iii.15, when he formally introduces the concept real essence as "the real internal, but generally in Substances, unknown Constitutions of Things, whereon their discoverable Qualities depend ," he is speaking about particulars which have not been named, i.e., particulars which have not been ranked or sorted under a general name such as Man or Gold. Thus in ill.iii.18 he discusses the real essence or corpuscularian microstructure of an unsorted particular, namely, "that particular parcel of Matter, which makes the Ring on my Finger," stating that it is "the real Constitution of its insensible Parts, on which depend all those Properties of Colour, Weight , Fusibility, Fixedness, etc. which are to be found in it" . And in ill.viA3 he contends that although discussing the real essences of unsorted particulars is both difficult and potentially misleading , it is also a crucial part of his case against essentialism. Thus Locke: But I desire, it may be considered, how difficult it is, to lead anoth er by Words into the Thoughts of Things, stripp'd of those specifical differences we give them: Which Things, if I name not, I say nothing; and if I do name them, I thereby rank them into some sort, or other , and suggest to the Mind the usual abstract Idea of that Species; and so cross my purpose. For to talk of a Man, and to lay by, at the same time, the ordinary signification of the Name Man, which is our complex Idea, usually annexed to it; and bid the Reader consider Man, as he is in himself, and as he is really distinguished from others , in his internal Constitution, or real Essence, that is, by something he knows not what, looks like trifling: and yet thus must one do, who would speak of the supposed real Essences and Species of Things, as thought to be made by Nature , if it be but only to make it understood , that there is no such thing signified by the general Names, which Substances are called by.

Just how Locke's treatment of the real essences of unsorted particulars fits into his case against essentialism will unfold in the subsequent sections of the chapter.

28

CHAPTER TWO 2. Unsorted particulars and accidental properties

As we have seen, Locke contends that unsorted particulars do not have any essential properties. That is, he does not merely contend that it is improper or insignificant to say that such a particular is essentially F, he contends that it is always false to say that this sort of thing. On at least two occasions he takes this to imply that all of the qualities of an unsorted particular are accidental to it, a view which I shall refer to as "accidentalism". 1 When, for example, he is discussing himself as an unsorted particular, he suggests that all of his qualities are accidental to him: Tis necessary for me to be as I am; GOD and Nature has made me so; But there is nothing I have, is essential to me. An Accident, or Disease, may very much alter my Colour, or Shape; a Fever, or Fall, may take away my Reason, or Memory, or both; and an Apoplexy leave neither Sense, nor Understanding, no nor Life. (III.viA)

And again in III.vi.6 he argues that all of the qualities of an unsorted particular are separable from it, since none of them are essential: That which is essential [to an individual parcel of matter], belongs to it as a Condition, whereby it is of this or that Sort: But take away the consideration of its being ranked under the name of some abstract Idea , and then there is nothing necessary to it, nothing inseparable from it.

Ayers finds this doctrine to be a function of Locke's mechanistic, corpuscularian ontology. Thus Ayers: The mechanist's world is one in which all differences are differences of degree, and everything is in principle indefinitely mutable. For all differences and changes are just differences and changes in the spatial quantity and ordering and motion of the parts of things. Crudely, the particular complex perceptible things in existence, particular men, horses, oak trees, quantities of gold etc., constitute a vast plurality, no two of which, for all we know, are precisely alike. (Ayers 1981,25658)2

The position which Ayers here attributes to Locke, that corporeal substances are indefinitely mutable, is precisely the view which I have labeled accidentalism. For to say that an object is indefinitely mutable is to say that

Here I follow Jose Benardete (1989, 149). See also Ayers (1991, 2:74). Clearly this account can only apply to things which are composed of atoms. That is, it cannot also apply to atoms themselves, for according to the corpuscularian hypothesis, atoms are immutable with respect to their size and shape. I

2

LOCKE'S CRITIQUE OF ESSENTIALISM

29

an object can undergo the loss of any of its properties, which is in turn to say that all of its properties are accidental to it. On other occasions, however, he suggests that unsorted particulars do not have accidental properties. Indeed, he suggests that they do not have accidental properties for the same reason that they do not have essential properties. In ill.viA, for example, he states that non-essential properties relate to sorts in the same way that essential propertie s do. "Essential, and not essential," he writes , "relate only to abstract ideas, and the names annexed to them." Since it is pretty clear that Locke takes non-essential properties to be accidental properties, this passage suggests that it is a mistake to attribute even accidental properties to an unsorted particular. On this view, the manifest qualities of an object which has yet to be sorted are neither accidental nor essential to it. For apart from falling under a sortal concept, this distinction has no application. The view Locke expresses here is paralleled by Quine's discussion of the cycling mathematician in Word and Object: Mathematicians may conceivably be said to be necessarily rational and not necessarily two-legged; and cyclists necessarily two-legged and not necessarily rational. But what of an individual who counts among his eccentricities both mathematics and cycling ? Is this concrete individual necessarily rational and contingently two-legged or vice versa? Just insofar as we are talking referentially of the object, with no special bias toward a background grouping of mathematicians as against cyclists or vice versa, there is no semblance of sense in rating some of his attributes as necessary and others as contingent. [Quine 1960, 199]

Observing the similarities between Locke and Quine at this juncture, William Uzgalis writes that "when Quine talks of considering the individual purely referentially, he parallels exactly Locke's talk of individuals considered barely in themselves. Both are asserting that necessity is relative to a sort or a description, and both are denying that there is any de re necessity" (Uzgalis 1988, 338-39). Following Benardete (1989, 161), I shall refer to this view as relativistic anti-essentialism. Although Locke endorses accidentalism in some passage and relativistic anti-essentialism in others, it is not clear that he would have been particularly comfortable with either of these views. In the first place, accidentalism seems to entail that unsorted particulars are indefinitely mutable . I think, however, that he would take this implication to be contrary to experience, if not also to reason. At ill.iiLI9, for example, he explicitly denies that objects or their real essences are (like Aristotle's substantial forms) ingenerable, incorruptible, and unchanging:

30

CHAPTER TWO All Things, that exist, besides their Author, are all liable to Change; especially those Things we are acquainted with, and have ranked into Bands, under distinct Names or Ensigns. Thus that, which was Grass to Day, is to Morrow the Flesh of a Sheep; and within a few days after, becomes part of a Man: In all which, and the like Changes, ' tis evident, their real Essence , i.e., that Constitution, whereon the Properties of these several things depended, is destroy'd, and perishes with them.

Since Locke thinks that things and their real essences can both be annihilated , he evidently thinks that there are limits to the alterations which corporeal substances can undergo and still continue to exist, which suggests that he is not an accidentalist, after all. In what remains I am going to take relativistic anti-essentialism to be his "official" view, since this position fits better with his thesis concerning the sortal relativity of essential properties . For when a sortal concept determines which of a thing's qualities are to be considered essential to it, it also determines which of them will not be considered essential. The problem with this view, of course, is that it seems to threaten Locke 's realism with respect to unsorted particulars . Suppose that we want to know whether Locke's gold ring continues to exist after it has been melted down and formed into a small cube. Relative to the sortal ring, certainly, it can no longer be said to exist, although relative to the sortal metal body, perhaps it does continue to exist. But, one might protest, we want to know whether it continues to exist, simpliciter. According to relativistic anti-essentialism there seems to be no fact of the matter: it continues to exist under some sortals, but not under others. We will be returning to this issue. 3. Real essences of sorted and unsorted particulars

I would like to draw attention to one final reason for thinking that Locke does not have a clear doctrine of unsorted particulars . In Ill, vi.6 he seems to take back his application of real essences to unsorted particulars, and to argue that real essences are themselves always relative to a sort: 'Tis true, I have often mentioned a real Essence, distinct in Substances, from those abstract Ideas of them, which I call their nominal Essence. By this real essence, I mean, that real constitution of any Thing, which is the foundation of all those Properties, that are combined in, and are constantly found to co-exist with the nominal Essence; that particular constitution, which every Thing has within it self, without any relation to any thing without it. But Essence, even in this sense, relates to a Sort, and supposes a Species: for being that real Constitution, on which the properties depend, it necessarily

LOCKE'S CRITIQUE OF ESSENTIALISM

31

supposes a sort of Things, Properties belonging only to Species, and not to Individuals. At first glance, this passage seems to be incompatible with his formal introduction of real essence at III.iii.15 as the corpuscularian microstructure of unnamed (and hence unsorted) particulars. That is, Locke seems to be saying both (i) that unsorted particulars have real essences, and (ii) that particulars have real essences only relative to this or that sort or kind. I contend that he can consistently hold both (i) and (ii), since they involve different concepts of 'real essence'. The real essence of an unsorted particular, I submit, is the total, corpuscularian microstructure which is causally responsible for all of its intrinsic and dispositional properties. "Every substance that exists," he writes in III. vi.I 3, "has its peculiar Constitution, whereon depend those sensible Qualities, and Powers, we observe in it." While this real essence belongs to an unsorted object de re, Locke would not allow that it or anything else belongs to it essentially, since apart from its being a member of a sort, there is no basis for dividing an object's properties into essential and non-essential. Clearly there is no way for this conception of real essence to be sortalrelative, for apart from these real essences and the qualities to which they give rise we would not be in a position to form sortal concepts in the first place. In a recent article, Pauline Phemister expresses this point nicely: Long before we get to the stage of constructing nominal essences, there must be real essences of [unsorted] individuals, for it is these particular, distinct real essences of individuals which cause in the first instance the array of sensible qualities from which the ones to be considered essential (the ones to be included in the nominal essence) are chosen. Particular real essences of individuals must provide the raw data from which the nominal essences are made. Nominal essences cannot be constructed out of nothing. The mind must have something to abstract from. What it abstracts from is the total array of sensible qualities in particular things, all of which are caused by their own particular, non-specific real essences. (phemister 1990, 3940)

With this point in hand, the next objective is to figure out how it is that he can also take there to be real essences which are sortal-relative. The key here is to see that when he is talking about real essences which are sortalrelative (e.g., at III.vi.6), he is applying the concept of real essences to particulars which have already been sorted into a kind which is defined by a nominal essence. That is, he is thinking of a thing's real essence as the cause of its (nominally) essential properties, or the properties which a thing has "as a Condition, whereby it is of this or that sort". Thus, for example,

32

CHAPTER TWO

the real essence of Locke's ring qua Gold is the structural characteristics of this ring which cause it to be yellow, heavy, ductile, malleable, and dissolvable in aqua regia, i.e., the structural characteristics which cause it to display the qualities associated with the nominal essence of gold. In contrast, the real essence of Locke's ring qua Metal is the structural properties of this ring which cause it to have the properties associated with the nominal essence of metal, i.e., those properties which gold has in common with iron, aluminum, copper, etc.. Thus unlike the real essence of an unsorted particular, the real essence of a sorted particular is not identified with its entire set of structural characteristics. Rather, it is identified with the smallest subset of these characteristics which is causally responsible for producing the qualities found in the nominal essence of the relevant sort.' Keeping this distinction in mind, let us now turn to Locke's treatment of natural kinds. His critique of essentialism begins with his contention that particular objects do not have essential properties per se, but only as members of a .particular species or kind. His next move is to attack the supposition that nature itself sorts things into species, so that each naturally occurring object is the member of a single, independently existing species . II. LOCKE ON THE NATURE AND EXISTENCE OF NATURAL KINDS

In IILiii.17 of the Essay Locke writes that there are ultimately only two opinions concerning the real essences of corporeal substances. The first opinion, he writes, "is of those, who using the Word Essence, for what they know now what, suppose a certain number of those Essences, according to which, all natural things are made, and wherein they do exactly everyone of them partake , and so become of this or that Species. The second, "more rational" opinion, he continues , "is of those who look on all natural Things to have a real, but unknown Constitution of their insensible Parts, from which flow those sensible Qualities, which serve us to distinguish them into sorts, under common Denominations." In Locke's subsequent discussion of these opinions , it becomes clear, first, that they represent competing theories about the way in which naturally occurring objects are divided into kinds or species; and second, that he affirms the second theory, and denies the first. In discussing Locke's treatment of natural kinds , we must not fall into the trap of trying to determine whether he does or does not reject natural kinds, per se. For there are many different theories about what it is for a group of individuals to constitute a natural kind, and each of these theories has a unique sense of "natural kind" .4 When he denies that there are real, 3 For a more detailed explanation of this account, see Peter Alexander (1985, 272-74). Similar accounts are given by Michael Ayers (1991, 2:74) and Stephen Law (1995, 74-75). 4 For a discussion of some of these theories, see Ian Hacking (1991). Hacking differentiates,

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33

objective chemical or biological species, he is rejecting a particular theory of natural kinds, one which states that nature sorts organisms and portions of chemical "stuff' into objective, non-overlapping , and sharply defined species. Thus before I develop the theory of kinds which he rejects, I think that it would be helpful to develop the theory which he accepts, according to which a species is any group of phenomenally-and hence microstructurally-similar individuals . 1. The "second opinion" regarding natural kinds

As we have just seen, Locke has two distinct concepts of 'real essence', one which pertains to sorted particulars , and one which pertains to unsorted particulars . The real essence of an unsorted particular is the set of microstructural characteristics which is causally responsible for all of its qualities and powers. The real essence of a sorted particular is the subset of these structural characteristics which is causally responsible for producing the qualities which are associated with the nominal essence of the relevant sort. Note that these structural characteristics should be present in all of the objects which are (accurately) ranked under a particular sortal concept. Since he thinks that there is a real essence for each species-which each of its members equally shares---there is a clear sense in which Locke affirms the existence of natural kinds. That is, if we take a natural kind to be any class of naturally occurring objects which share a common set of microstructural properties, then presumably at least some of Locke's sortal concepts (e.g., concepts like Gold or Horse) demarcate natural kinds. I shall henceforth refer to these as Lockean kinds or species. At least one of Locke's philosophically sophisticated correspondents took his treatment of genera and species to rule out even Lockean kinds. In a letter dated 22 December 1692, William Molyneux makes the following comment about Locke's theory of classification: What you say concerning Genera and Species is Unquestionably true, and yet it seems hard to assert, that there is no such sort of Creatures in Nature as Birds; for tho we may be Ignorant of the Particular Essense that make a Bird to be a Bird, or that Determines and Distinguishes a Bird from a Beast, or the just Limits and boundarys between each; Yet we can no More doubt of a Sparrows being a Bird, and an Horses being a Beast, then we can of this Colour being Black and tother White, tho by Shades they may be so Gradually to Vanish

for example, between Russell-kinds, Mill-kinds, Peirce-kinds , and Leibniz-kinds.

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CHAPTER TWO into each other , that we cannot tell where either Determines.5 (no.1579, iv:601)

Unless he is just being polite, it is strange that Molyneux should confess Locke' s position on genera and species to be unquestionably true. For he thinks that this position implies the apparently false conclusion that there is no such sort of Creatures in Nature as Birds. Although he does not say why he takes Locke's position to have this implication, I suspect that this reading is prompted by Locke' s frequent suggestion that genera and species are merely useful, linguistic fi ctions. Thus, for example, at m. vi.9 he writes that genera and species "appear, upon a more wary survey, to be nothing else but an Artifice of the Understanding, for the easier signifying of such Collections of Ideas, as it should often have to communicate by one general term." In light of statements such as this, it is no wonder that Molyneux should take Locke' s position to entail that "there is no such sort of Creatures in Nature as Birds," i.e., that there is no sense in which the sort Bird exists objectively in nature. Locke' s response to Molyneux' s reading of Book III comes in a letter dated 20 January 1693. He begins by disavowing the view which Molyneux has attributed to him: Consider what it is you mean when you say, that we can no more doubt of a sparrow's being a bird, and an horse 's being a beast, then we can of this colour being black, and t' other white, etc. but this, that the combination of simple ideas which the word bird stands for, is to be found in that particu lar thing we call a sparrow . And therefore I hope I have no where said, there is no such sort of creatures in nature as birds; if I have, it is both contrary to truth and to my opinion. (no.1592, iv:626)

Here Locke denies that genera and species are merely useful fictions which have no objective or mind-independent reality. With Molyneu x, he thinks that it is false to say that 'there is no such sort of creatures in nature as birds.' Rather, he thinks that this species exists in nature, since it is a fact about nature that particular objects exist whose manifest properties conform to the nominal essence of this sort. Locke goes on to briefly restate his position on species, and in the process he makes a further claim about their objectivity: This I do say, that there are real constitutions in things from whence those simple ideas flow, which we observ' d combined in them. And this I further say, that there are real distinctions and differences in All references to Locke' s correspondence will be to the Clarendon edition, and will occur parenthetically by way of the letter number, followed by the volume and page numbers.

5

LOCKE'S CRITIQUE OF ESSENTIALISM

35

those real constitutions one from another; whereby they are distinguished one from another, whether we think of them or name them or no.

Here Locke suggests that objects can also be objectively similar or dissimilar at the structural level, and although he does not clearly say so here, elsewhere he contends that objects which are similar at the phenomenal level are also likely to be similar at the structural level. Thus, for example, he writes that "Nature makes many particular Things, which do agree one with another, in many sensible Qualities, and probably too, in their internal frame and Constitution" (ill. vi.36). In the last part of his response to Molyneux, Locke reiterates two additional points which frequently arise in ill.iii and vi: But that whereby we distinguish and rank particular substances into sorts or genera and species, are not those real essences or internal constitutions, but such combinations of simple ideas we observe in them.

Here Locke contends that our sortal practices are carried out exclusively at the level of experience, and hence that they are not directly informed by these "real essences or internal constitutions". Elsewhere he makes it clear why these real essences are irrelevant to our sortal practices. We do not sort things into species by their real essences, he contends, "because we know them not" (ill. vi.9). Indeed, he does not merely think that we are presently incapable of knowing these real essences, he thinks that these real essences are unknowable, in principle. For, he continues, Our Faculties carry us no farther towards the knowledge and distinction of Substances, than a Collection of these sensible Ideas , which we observe in them; which is more remote from the true internal Constitution, from which those Qualities flow, than...a Countryman 's Idea is from the inward contrivance of that famous Clock at Strasbourg, whereof he only sees the outward Figure and Motions. (III.vi.9)

In sum, a Lockean species or kind is a class of phenomenally and (presumably) structurally similar objects. Although some passages suggest otherwise, he does not think that these species are merely useful fictions which have no objective status whatever. For there is an important sense in which they are objective: they are objective because the phenomenal similarities which give rise to them are objective, and because the structural similarities which underlie these phenomenal similarities are also objective. In other words, these kinds can be said to exist in nature, because these similarities are made by nature. But we must be careful not to overstate

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CHAPTER TWO

their objectivity. Although he thinks that these phenomenal and structural similarities are made by nature, he does not think that these species are made by nature. Rather, he contends that we create these species, and that we do so by (intentionally or unintentionally) focusing on some of these objective similarities, and by excluding (or ignoring) others. Hence he does not think that these species exist independently from our classificatory decisions. I contend that this account of species is equivalent with the second opinion concerning kinds, mentioned above. Once more, the second opinion maintains that "all natural Things to have a real, but unknown Constitution of their insensible Parts, from which flow those sensible Qualities, which serve us to distinguish them into sorts, under common Denominations" (III.iiLI7). Since he maintains that qualitative similarities and differences are a function of micro-structural similarities and differences, he could not have affirmed (or denied) either without affirming (or denying) the other, which is just to say that these positions are equivalent. I conclude, therefore, that the positive theory of natural kinds which has been developed in this section is none other than the second theory of kinds mentioned in III.iii.17.

2. The "first opinion

H

regarding natural kinds

Now that we have determined the sense in which Locke affirms the existence of natural kinds, it is not difficult to determine the sense in which he denies their existence. In his words, this opinion belongs to those who "using the Word Essence, for what they know not what, suppose a certain number of those Essences, according to which, all natural things are made, and wherein they do exactly every one of them partake, and so become of this or that Species" (III.iiLI7). He goes on to say that advocates of this view suppose all natural things to have been fashioned or "cast" by means of these essences "as a certain number of Forms or Molds". The first thing we should notice about the first, "less rational" theory is that it does not deny that we sort things into Lockean kinds. Obviously enough, this is a theory about what nature does, not about what we do. In particular, it is a theory about how nature divides objects into species at the structural level, and so it is not concerned with how we classify objects at the phenomenal level. The explanation of how nature is thought to do this comes in two parts. This view maintains both (i) that nature creates a limited number of specific real essences, "as a certain number of Forms or Molds", and (ii) that nature casts each particular object from exactly one of these molds. Thus, the first opinion maintains that each particular object belongs to exactly one (lowest) species, so that there can be no overlap

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between such species. In addition, this account maintains that members of the same species will share exactly the same specific real essence. Thus at IILx.20 he writes that nature, on this view, "sets the Boundaries to each of those Species, by giving exactly the same real internal Constitution to each individual." Since he does not think that members of such a species would have to be qualitatively indiscernible on this account, we should not take him to be suggesting that there cannot be any differences between these real constitutions . But clearly they would have to be alike in a significant and non-trivial manner. For as we shall see shortly, he thinks that members of the same species would have to be qualitatively similar, at least in certain relevant respects such as color, size, and shape. Following Locke's usage at IILvi.23, I shall henceforth refer to the sorts of kinds which the first opinion takes to exist in nature as real kinds or species. If nature does sort individuals into real kinds, then what would our role be, as classifiers? On this view, our role would be merely to locate these natural divisions, hence the supposition-which he rejects-that our taxonomic categories are "exactly copied from precise Boundaries set by Nature, whereby it distinguishes all substances into certain Species" (III.vi.27). Locke's characterization of these boundaries as precise highlights another facet of this position : not only does he think that there should be no overlap between real species, he also thinks that these boundaries would be clearly demarcated, that they would not imperceptibly shade into one another. We shall return to these positions shortly. It is not hard to differentiate between the notion of kinds which Locke would embrace and the notion which he rejects. The divisions between Lockean species are created by us, and they are created by us at the phenomenal level. The divisions which are alleged to exist between real species are created by nature, and they are created by nature at the microstructural level. Hence Lockean species are objective in a fairly weak sense, since they do not exist apart from our classificatory decisions. Conversely, real species-e-should they exist-would be objective in a much deeper sense, for their existence would not be dependent upon our classificatory decisions. Indeed, they would exist whether anyone recognized them or not. Now it is frequently suggested that the first opinion on real essences is none other than the scholastic/Aristotelian doctrine of substantial forms." In defense of this position, David Owen and Stephen Law both appeal to Locke's use of 'forms' in his contention that this view "supposes that these

6 Thus Roger Woolhous e (1971, 99,101); J. L. Mackie (1976, 86); Evan Fales (1982, 68, 72n.7); Peter Alexander (1985, 267); Ruth Mattern (1986, 54) ; William Uzgalis (1988, 330t) ; David Owen (1991, 109); Paul Guyer (1994 , 117); and Stephen Law (1995, 80).

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Essences, as a certain number of Forms or Mold s, wherein all natural Thing s, that exist, are cast, and do equally partake. " This use of 'forms', it is argued, indicates that he is concerned with the scholastic/Aristotelian account of natural kinds. I contend that Locke does not identify the first opinion with the scholastic/Aristotelian doctrine of substantial forms. Instead, I argue that he takes this to be a generic position about real essences, in keeping with his definition of 'real essence ' "as the very being of something, whereby it is what it is". I maintain , in addition , that he recognize s two versions of the first opinion: (i) a scholastic/Aristotelian version, according to which each species is characterized by a particular, substantial form, and (ii) a corpuscularian version, according to which each species is characterized by a distinct, (corpuscularian) real essence type. This conclusion is required, I contend, because he takes the first opinion seriously. He does not begin by characterizing it as unintelligible, but simply as less rational than his opinion, and ultimately, as false. But he would not have characterized the first opinion in this manner if he had identified it with the doctrine of substantial forms. For this doctrine, he thinks , is completely incoherent. Thus in III.vi.10 he writes: Those therefore who have been taught, that the several Species of Substances had their distinct internal substantial Forms; and that it was those Forms , which made the distinction of Substances into their true Species and Genera, were led even farth er out of the way, by having their Minds set upon fruitless Enqu iries after Substantial Forms, wholly unintelligible, and whereof we have scarce so much as any obscure, or confused Conception in general.

In addition to dismissing the scholastic!Aristotelian account of natural kinds as "wholly unintelli gible," he also suggests that there is a version of this doctrine-that nature is objecti vely divided into real specie s-which has a better chance of being correct, i.e., a version which is not "even farther out of the way". This version, I submit, is precisely the corpu scularian account of real specific essences mentioned above . He takes the corpuscularian account of real species seriously, I suspect, because he finds it to be an intelligible version of a prevalent and insidiou s theory. In the first place, it is not absurd to suppose that the weakly objective division s which we create between species at the phenomenal level correspond with the much more deeply objective divisions which nature allegedly makes between species at the structural level. I take him to express precisely this point in II.xxxi.6 . In this passage, he begins by recounting the fundamental thrust of the first opinion , which is that the

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individual real essence of each naturally occurring object determines it membership in a single, lowest species. Thus Locke: Though we know nothing of these real Essences , there is nothing more ordinary, than that Men should attribute the sorts of Things to such Essences . The particular parcel of Matter which makes the Ring I have on my Finger, is forwardly, by most men, supposed to have a real Essence, whereby it is Gold ; and from whence those Qualities flow, which I find in it.

Locke subsequently recounts the one version of this opinion which he can make sense of: This essence, from which all these Properties flow, when I enquire into it, and search after it, I plainly perceive I cannot discover: the farthest I can go, is only to presume, that it being nothing but Body, its real essence, or internal Constitution, on which these qualities can depend, can be nothing but the Figure, Size, and Connexion of its solid Parts.

And finally, he reiterates his contention that the scholastic/Aristotelian version of this opinion is thoroughly unintelligible: If anyone will say, that the real Essence, and internal Constitution, on

which these Properties depend, is not the Figure, Size, and Arrangement or Connexion of its solid Parts, but something else, call'd its particular form ; I am farther from having any Idea of its real essence, than I was before. For I have an Idea of Figure, Size, and Situation of solid Parts in general , though I have none of the particular figure, Size, or putting together or parts, whereby the Qualities above-mentioned are produced ....But when I am told, that something besides the Figure, Size, and Posture of the solid Parts of that Body, is its Essence, something called substantial form, of that, I confess, I have no idea at all.

But why should Locke take the first opinion to be an insidious theory? The best I can tell is that he takes this theory to have engendered a kind of dogmatism, which has subsequently impeded the progress of the natural sciences. This would accord well with the objective which he announces in the Epistle to the Reader ' tis Ambition enough to be employed as an Under-Labourer in clearing Ground a little, and removing some of the Rubbish, that lies in the way to Knowledge ; which certainly had been very much more advanced in the World, if the Endeavours of ingenious and industrious Men had not been much cumbred with the learned but

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CHAPTER TWO frivolous use of uncouth, affected, or unintelligible Term s, introduced in to the Sciences.

If the first opinion is also concerned with the corpuscularian account of natural kinds, then what are we to make of his statement that a proponent of this view "supposes that these Essences, as a certain number of Forms or Molds, wherein all natural Things, that exist, are cast, and do equally partake "? Law and Owen both take Locke's use of 'forms' to indicate that he identifies the first opinion with the scholastic/Aristotelian account of natural kinds. I contend that his use of 'forms' does not require this interpretation. For in this passage Locke does not identify real essences with substantial forms, as he would if he were explicitly thinking of the doctrine of substantial forms. Rather, his use of 'as' suggests that he takes these real essences to be functionally equivalent with substantial forms. That is, he takes these corpuscularian real essences both (i) to sharply determine the boundaries between species, and (ii) to explain the properties of each member of the species," Since Locke is pretty clearly opposed to two different versions of the theory that corporeal substances are objectively divided into species, it would be odd if his criticism of the first opinion were aimed solely at the scholastic/Aristotelian version, i.e., the version which he finds to be utterly unintelligible. It is more plausible to suppose that his criticism of the first opinion is aimed primarily at the corpuscularian account of real species, i.e., the version which he does not take to be downright unintelligible. In other words, it is more plausible to suppose that Locke takes the first opinion seriously because he takes the corpuscularian version of this account seriously, and in spite of the fact that he is completely dismissive of the scholastic!Aristotelian version of this account.

3. Locke's epistemological and semantic arguments against real kinds On some accounts Locke is merely agnostic about the existence of real kinds." Against this interpretation, I contend that he denies their existence,

that he takes "the Imaginations of setled and fixed species in Nature" to be a chimera. In at least one passage Locke says as much: in III.x.21 he explicitly characterizes as false "the supposition that there are certain precise Essences, according to which Nature makes all particular Things, and by which they are distinguished into Species." If this interpretation is to be successful, however , it must face up to the fact that much (if not most) of And according of Ayers, Locke doesn't think that anything could perform both functions (1991,2: 67-8). 8 Thus Phemister (1990). 7

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what he says against the doctrine of real kinds seems to be compatible with their existence. Take, for example, his various epistemic arguments against the doctrine of real kinds. Throughout the Essay Locke repeatedly argues that we cannot know the real essences of corporeal substances. These arguments are frequently directed against those who purport to divide particulars into kinds in a way that corresponds to their natural divisions, and Locke rightly thinks that if we do not know what objects are like at the structural level, then we should not presume to have discovered these natural boundaries. In IlLvi.9, for example, he writes: The Workmanship of the All-wise, and Powerful God, in the great Fabrick of the Universe, and every part thereof, farther exceeds the Capacity and Comprehension of the most inquisitive and intelligent Man, than the best contrivance of the most ingenious Man, doth the Conceptions of the most ignorant of rational Creatures . Therefore we in vain pretend to range Things into sorts, and dispose them into certain Classes, under Names, by their real Essences, that are so far from our discovery or comprehension . A blind man may as soon sort Things by their Colours, and he that has lost his Smell, as well distinguish a Lily and a Rose by their Odors, as by those internal Constitutions which he knows not.

Sometimes Locke takes the inaccessibility of real essences to have a stronger implication. Since we don't have access to the real essences of corporeal substances , he suggests, the supposition that there is a particular real essence type for each natural species can be of no use to us, so it should be dismissed. Indeed, in one passage he writes as if this consideration alone is enough to warrant our dismissal of real kinds. Thus Locke : But were there no other reason against it, yet the supposition of Essences, that cannot be known; and the making them nevertheless to be that, which distinguishes the Species of Things , is so wholly useless, and unserviceable to any part of our Knowledge, that that alone were sufficient, to make us lay it by. (III.iii.l7)

But even if we grant that the real essences of corporeal substances are epistemically inaccessible to us, and consequently that we would be unjustified in thinking that our way of dividing individuals into Lockean species corresponds to the way in which nature allegedly divides things into real species, it might still be the case that nature does divide things into species in this manner. And even if we concede that this supposition about naturally endowed, essential natures is "wholly useless, and unserviceable to any part of our Knowledge," it might still be true.

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Locke's semantic arguments against the supposition of real specific essences are similarly incapable of demonstrating the falsity of this supposition. In order to develop these arguments, I need to say a few words about his general theory of meaning. According to Locke, a word has a meaning for someone in virtue of its being associated with an idea in his mind." In IIIjL I he contends that the connection which we form between a particular word and a particular idea is an arbitrary one: we might have associated a different word with a given idea, or vice versa. Thus, he writes that the association between a word and an idea is made by a "voluntary imposition, whereby such a Word is made arbitrarily the Mark of such an Idea ." In the subsequent section he takes the voluntary nature of the connection between words and ideas to have an important implication: "Words being voluntary signs, they cannot be voluntary Signs imposed by him on Things he knows not." On Locke's account, one cannot will to associate a word with an idea that one does not have. "If words have no natural meanings," Guyer explains, "but only such meaning as we as speakers have given them, their meanings cannot lie in anything unknown to us, but must be drawn from our own stock of knowledge" (1994, 119). Thus according to Locke, general terms cannot refer to that of which we are not aware. In III.x.20 Locke observes that those who claim to be capable of distinguishing between the various real essences of natural species frequently take their general terms to refer to these essences. Thus Locke: That which, I think, very much disposes Men to substitute their names for the real Essences of Species, is the supposition before mentioned, that Nature works regularly in the Production of Things, and sets the Boundaries to each of those Species, by giving exactly the same real internal Constitution to each individual, which we rank under one general name.... This supposition, however that the same precise internal Constitution goes always with the same specifick name, makes Men forwa rd to take those names for the Representations of those real Essences, though indeed they signify nothing but the complex Ideas they have in their Minds when they use them.

Given that we don't have any knowledge of these real essences, he takes it to be absurd "to make our names stand for Ideas we have not, or (which is all one) Essences that we know not, it being in effect to make our Words the signs of nothing" (III.x.21). And since our words and ideas are precluded from referring to essences in nature, he contends that "to talk of specific Exempt from this theory of meaning is the class of words which Locke refers to a 'particles ', i.e., words such as 'and ', 'but' , and 'if , which "signify the connexion that the Mind gives to Ideas, or Propos itions. one with another' (III.viLl) .

9

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Differences in Nature, without reference to general Ideas and Names, is to talk unintelligibly" (III.vi.5). In ITL vi.33 Locke sums up both his semantic and epistemic considerations against the view that nature is divided into deeply objective kinds by real essences or substantial forms, writing that "real essences, or substantial Forms ...come not within the reach of our Knowledge, when we think of those things; nor within the signification of our Words, when we discourse with others ." The problem remains, however, that these semantic and epistemic considerations do not tell against the existence of real kinds. Thus on the basis of these arguments he is not entitled to conclude that there are no objective boundaries between species in nature. Rather, he is only entitled to conclude that we do not know whether they exist, and that we cannot speak intelligibly about them either way. In one passage he seems to concede this very point: Since the Composition of those complex Ideas, are, in several Men, very different: and therefore, that these Boundaries of Species, are as men, and not as nature makes them, if at least there are in Nature any such prefixed Bounds. 'Tis true, that many particular Substances are so made by Nature, that they have agreement and likeness one with another, and so afford a Foundation of being ranked into sorts. But the sorting of Things by us, or the making of determinate Species, being in order to naming and comprehending them under general terms, I cannot see how it can be properly said, that Nature sets the Boundaries of the Species of Things: Or if it be so, our Boundaries of Species , are not exactly conformable to those in Nature. (III.vi.30)

Here Locke seems to admit both that there might be natural boundaries between species, and that these boundaries mayor may not correspond with the boundaries which we have created. These sentiments are also expressed in Draft B of the Essay. In §75 of Draft B he writes: Though there be a foundation in nature for the dividing of things into sorts and tribes, yet because we seldom know the precise bounds where one ends & the other begins & where the destinction is made between them, & yet having need of names in the meane time, we devide them into species in respect to our selves. (183)

Statements such as these, coupled with the fact that his epistemic and semantic arguments do not rule out the possibility of epistemically inaccessible real kinds, lead Phemister to conclude that Locke is merely agnostic about their existence, and hence that his position "failed to culminate in a full-blown denial of natural kinds" (1990, 28).

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CHAPTER TWO 4. Locke's appeal to monsters and changelings

Against Phemister, I maintain that Locke denies the existence of real kinds. In addition to explicit statements to this effect like the one mentioned above at ill.x.21, perhaps the best indication of this denial is his repeated insistence that the existence of real kinds is incompatible with the existence of monsters and changelings. By 'changeling' Locke seems to mean a mentally retarded or severely deformed human being; a monster, on the other hand, appears to be the offspring of parents from distinct species. In llI.vi.23 he instances several allegedly common examples of monsters, among them, the offspring of a woman and a drill (a species of baboon), mules, and gimars (the legendary offspring of a bull and a mare). In this passage he also claims to have witnessed one monstrous production firsthand. "I once saw a Creature," he writes, "that was the Issue of a Cat and a Rat, and had the plain Marks of both about it; wherein Nature appear'd to have followed the Pattern of neither sort alone, but have jumbled them both together." Speaking of the first opinion, that there are a "certain number of those [real] Essences, according to which, all natural things are made, and wherein they do exactly every one of them partake, and so become of this or that Species," he writes: The frequent Productions of Monsters, in all the species of Animals, and of Changelings , and other strange Issues of humane Birth, carry with them difficulties, not possible to consist with this Hypoth esis : Since it is as impossible, that two Things, partaking exactly of the same real Essence , should have different properties, as that two Figures partaking of the same real Essence of a Circle, should have different properties. (lII.iii .17)

Here Locke clearly takes the "frequent production" of monsters and changelings to entail the falsity of the first opinion. Indeed, he takes this implication to be obvious, once we recognize that two things exactly partaking of the same real essence type cannot have markedly different manifest properties. In order to see why he takes this to be obvious, we must recall his assumptions about the boundaries which would obtain between species which have been created by nature in accordance with the first opinion. As we have seen, Locke makes two assumptions about the nature of these boundaries. First, he assumes that these boundaries would not cross over one another, and hence that that nothing could belong to two (lowest) species at the same time. Second, he assumes that the boundaries between

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real species would be certain and precise, i.e., that they would be clearly demarcated, and that they would not imperceptibly shade into one another. " It is not hard to see why he makes the first of these assumptions, given his commitment to the thesis that qualitative similarities (dissimilarities) are a function of micro- structural similarities (dissimilarities). For if the members of a given species share a common set of micro-structural characteristics, and in particular, if the micro-structural characteristics of these objects are similar in a significant and non-trivial manner, then it would be reasonable to expect the members of this species to resemble one another in a significant and non-trivial manner. But what grounds does Locke have for the second assumption, that the members of distinct species would exhibit noticeably different qualities? Clearly it would not be enough to appeal to the thesis that differences at the qualitative level reflect differences at the micro-structural level. For this would only warrant the conclusion that the member of different species would exhibit some differences, but not necessarily conspicuous differences. Perhaps he thinks that the structural differences between the members of distinct specie s would have to be significant and non-trivial, in contradistinction to the sort of similarities which are supposed to exist between members of the same species, and that these significant structural differences would thereby precipitate significant qualitative differences. If this account of how nature works is correct, then locating the divisions between real kinds should be a relatively simple matter, since the members of a single species should be qualitatively alike (at least in certain , relevant respects), and since the qualities typified by anyone specie s should be distinguishable from the qualities typified by every other species. Indeed, if this account is correct, we should not run into individuals which fail to fit neatly into any particular group . In short, we should not encounter monsters and changelings. Since Locke thinks that we do encounter monsters and changelings, he concludes that the first opinion is false. His argument regarding monsters and changelings helps to explain why he thinks that the perva sive phenomenon of (sincere) disagreement over the species membership of particular organisms tells against the very existence of objectively existing species. In m.vi.27, for example, he argues that people would never disagree about whether a physically deformed child belongs to the species Man "if the nominal essence, whereby we limit and distinguish the Specie s of substances, were not made by Man , with some liberty; but were exactly copied from precise Boundaries set by Nature, 10 Against Locke, Leibniz suggests in the New Essays that there might be "insensible transitions from one species to another...[such that] telling them apart might sometimes be rather like the problem of deciding how much hair a man must have if he is not to be bald"

(III.vi.27: 32 1).

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whereby it distinguished all Substances into certain Species" (llI. vi.27, emphasis added).'! Here again, he assumes that if nature sets the boundaries between species, then these boundaries will be precise and clearly demarcated. Hence he thinks that if things are sorted into kinds by nature, then it should be relatively easy to sort things into their respective kinds. In other words, Locke assumes that if things were sorted by nature into real, objective species, then there would not be much room for disagreement over whether an individual belongs to a given species. And since this is not the case, he concludes that nature does not in fact act in this manner. In III.vi.29 Locke distinguishes between two kinds of corporeal substances, those which are propagated by seed (i.e., plants and animals) and those which are not (e.g., gold and silver). While his appeal to monsters and changelings is only directed against the thesis that there are objectively existing biological species, he has a similar argument against real chemical species . Thus in III.vi.8 he writes: That the Species of Things to us, are nothing but the ranking them under distinct Names, according to the complex Ideas in us; and not according to precise, distinct real Essences in them, is plain from hence; That we find many of the Individuals that are ranked into one Sort, called by one common Name, and so received as being of one Species, have yet qualities depending on their real Constitutions, as far different one from another, as from others, from which they are accounted to differ specifically. This, as it is easy to be observed by all, who have to do with natural Bodies; so Chymists especially are often, by sad Experience , convinced of it, when they, sometimes in vain, seek for the same Qualities in one parcel of Sulphur, Antimony, or Vitriol, whey they have found in others. For though they are Bodies of the same Species, having the same nominal Essence, under the same Name; yet do they often, upon severe ways of examination , betray Qualities so different one from another, as to frustrate the Expectation and Labour of very wary Chymists. But if Things were distinguished into Species, according to their real essences, it would be as impossible to find different properties in any two individual Substances of the same Species, as it is to find different Properties in two Circles, or two equilateral Triangles .

In a manner reminiscent of his treatment of biological kinds, he thinks that

"if Things were distinguished into Species, according to their real essences," then we should not encounter portions of matter which do not fit neatly into any particular category. Nor should we encounter portions of matter which we take to belong to the same chemical species, but which display markedly

11 Locke

also makes this point at III.iii.14, and at vi.26, 30, and 31.

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different manifest properties. But since chemists frequently report these sorts of occurrences, he concludes that real chemical species do not exist. Locke 's appeal to monsters and changelings, and the analogous appeal to qualitative overlapping the case of chemical species, demonstrates that he is not merely agnostic about the existence of natural kinds, but that he rejects them entirely. According to Locke, things are not sorted into kinds by nature. Rather, it is we who sort them into kinds. In what remains of this chapter I shall present his positive account of how this task is accomplished. III. LOCKE ON THE CLASSIFICATION OF CORPOREAL SUBSTANCES

The first element of Locke's critique of essentialism is his contention that the attribution of essential properties to an object is always conditional upon its beings ranked into a sort or kind. The second element of this critique is his denial of ontologically privileged sortals, i.e., his denial that things are sorted by nature into objective kinds. In what remains of this chapter I shall develop the final element of this critique, namely, his contention that it is we who sort things into kinds, and that we do so in a manner which is both underdetermined by nature, and arbitrarily determined by our (idiosyncratic) interests and activities. I begin by discussing his account of how particular objects are sorted into kinds. I subsequently discuss what he says about the formation of sortal concepts or nominal essences. J. Sorting particulars into kinds

According to Locke, we form sortal concepts by observing the objective similarities which exist between particular objects. Thus in III.iiL13 he writes: I would not here be thought to forget, much less deny, that Nature in the Production of Things, makes several of them alike: there is nothing more obvious, especially in the Races of Animals, and all Things propagated by Seed. But yet, I think, we may say, the sorting of them under Names, is the Workmanship of the Understanding, taking occasion from the similitude it observes amongst them, to make abstract general Ideas, and set them up in the mind, with Names annexed to them, as Patterns, or Forms...to which, as particular Things existing are found to agree, so they come to be of that Species, have that Denomination, or are put into that Classis.

Here Locke contends that as objects are presented to our senses, we cannot help but notice that the manifest qualities of some are very like those of others. The perception of these similarities, in turn, enables us to form abstract ideas of various kinds of things. Thus, forming an abstract idea,

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say, of Man or Horse involves retaining what is common to all of our perceptions of particular men or horses . "Ideas become general," he writes in III.iii.6, "by separating them from them from circumstances of Time, and Place, and any other Ideas, that may determ ine them to this or that particular Existence. By this way of abstraction they are made capable of representing more Individuals than one, each of which, having in it a conformity to that abstractIdea, is (as we call it) of that sort." Locke does not think that he needs to defend this account-he simply appeals to our experience. "Let anyone reflect, and then tell me," he writes in III.iii.9, "wherein does his Idea of Man differ from that of Peter, and Paul; or his Idea of Horse , from that of Bucephalus, but in leaving out something, that is peculiar to each Individual, and retaining so much of those particular complex Ideas, of several particular Existences, as they are found to agree in?" Thus, for example, while sifting through a pile of objects variously composed of gold, silver or copper, we could form an idea which applies to all and only those objects which are made of gold. This general or abstract idea of gold is what Locke eventually refers to as the nominal essence of Gold. Thus he writes in III.vi.2 that the nominal essence of gold "is that complex Idea the word Gold stands for, let it be, for instance, a Body yellow, of a certain weight, malleable, fusible, and fixed." On Locke's account, sorting individuals into kinds presupposes that we already have an assortment of nominal essences at our disposal , since an object is ranked into a sort only if its properties conform with the nominal essence of this sort. Thus, for example, he writes that 'Tis impossible...that any thing should determine the Sorts of Things , which we rank under general Names , but that Idea, which that Name is design'd a mark for; which is that, as has been shewn , which we call the Nominal Essence. Why do we say, This is a Horse , and that a Mule; this an Animal, that an Herb ? How comes any particular Thing to be of this or that Sort, but because it has that nominal essence, Or, which is all one , agrees to that abstract Idea, that name is annexed to. (lII.vi.7)

In short, an animal is ranked under the sortal Horse only if its manifest qualities conform to our abstract idea of Horse, and a parcel of matter is ranked under the sortal Gold only if its manifest qualitie s conform to our abstract idea of Gold .12 Now Locke seems to think that if we all had the same abstract idea of Gold, then we would always be able to agree about whether or not a particular parcel of matter is gold, since we would all be equally able to compare our idea of this object with our abstract idea of gold. That is, he 12

See also III.iii.l3 and vi.36.

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takes it for granted that we can accurately compare our perceptions of particular objects with our abstract ideas. Whence the disagreements over classification and over the attribution of essential properties? People disagree over classification, and consequently over the attribution of essential properties, precisely because they are working with different abstract ideas. In the next section I shall outline why Locke takes these disagreements to be almost inevitable.

2. Forming sortal concepts According to Locke, forming complex ideas of substances involves joining only those ideas of qualities which one takes to coexist in nature. For this reason, he thinks that the formation of complex ideas of substances is less arbitrary than the formation of complex ideas of mixed modes." Thus in III.v.3 he writes that the Essences of the Species of mixed Modes, are not only made by the Mind, but made very arbitrarily, made without Patterns, or reference to any real existence. Wherein they differ from those of Substances, which carry with the Supposition of some real Being, from which they are taken, and to which they are conformable.

The fact that one always attempts to follow nature in the formation of complex ideas of substances does not prevent them from being made "with some latitude" (III.iv.17). For even though we attempt to follow nature in joining only those ideas which we perceive to be united in one substance, the contents of our complex ideas of substances are never determined solely by nature, but also by human choice and convention. Thus he writes in III.vi.29 that "though the Mind of Man, in making its complex Ideas of Substances, never puts any together that do not really, or are not supposed to co-exi st; and so it truly borrows that Union from nature: Yet the number it combines, depends upon the various Care, Industry, or Fancy of him that makes it." On Locke's account, the process of forming sortal concepts is a highly indeterminate one. Nature presents us with qualitatively similar and dissimilar individuals and portions of stuff. These individual s and portions are indeed similar and dissimilar in any number of ways. We draw the boundaries between species by focusing on a particular subset of these similarities, and in the process we inevitably neglect or ignore other, equally legitimate sets of similarities. Thus, for example, focusing on one set of similarities and dissimilarities between a certain group of individuals has led

13

See III.iii.14; and vi.6, 7, 8,9, 18, and 20.

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us to recognize panthers, jaguars and leopards as three distinct species of the genus Cat. And in connection with parcels of matter, this practice has let us to recognize gold, copper and brass as three distinct species of the genus Metal. According to Locke, there is nothing sacrosanct about these categories, since there is nothing sacrosanct about the similarities which gave rise to them. For we might easily have focused upon a different set of similarities, and in so doing, we might have created other categories which would have been equally serviceable. Most often Locke assumes that we are already working with a commonly accepted set of taxonomic categories, one, for example, which takes jaguars, leopards, and panthers to be distinct species of the genus Cat, and which takes brass, copper, and gold to be distinct species of the genus Metal. Even within an accepted taxonomy, however, our actual ideas of these substances are largely indeterminate. The fact that we take gold to be a distinct species of metal, for example, does not place many constraints upon our complex idea of gold. Let us assume, with Locke, that our complex idea of gold is that of a body which is yellow, malleable, heavy, ductile, and dissolvable in aqua regia. As he correctly points out, some of these properties are dispositional: to say that a thing is malleable is to say that if we were to pound on it in the appropriate way, then it would flatten out into a thin sheet. To say that it is dissolvable in aqua regia is to say that ifwe were to place it in a mixture of nitric and hydrochloric acids, then the bonds connecting its material parts would be broken, and so on for all of its other dispositional properties. Once we recognize that substances like gold have dispositional properties, it becomes clear that most of their properties will be dispositional, and indeed that each substance will have a virtually infinite number of dispositional properties. Speaking of gold Locke writes: No one, who hath considered the Properties of Bodies in general, or this sort in particular, can doubt, that this, call'd Gold, has infinite other properties, not contained in that complex Idea. Some, who have examined this Species more accurately, could, I believe, enumerate ten times as many Properties in Gold, all of them as inseparable from its internal Constitution as its Colour, or Weight: And 'tis probable, if anyone knew all the Properties, that are by divers Men known of this Metal, there would be an hundred times as many Ideas , go to the complex Idea of Gold, as many as on Man yet has in his; and yet, perhaps, that not be the thousandth part of what is to be discovered in it. The changes that that one Body is apt to receive, and make in other Bodies, upon a due application, is exceeding far, not only what we know, but what we are apt to imagine. (II.xxxi.lO)

Given that substances such as gold have an indefinite number of discoverable properties, Locke thinks that we will inevitably form different

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nominal essences of gold, since some are more industrious and resourceful than others in identifying these properties. Thus, another way in which nature underdetermines our complex ideas of substances is by endowing substances with so many discoverable properties. Of these properties, he writes: They being therefore at least so many, that no Man can know the precise and definite number, they are differently discovered by different Man, according to their various skill, attention, and way of handling ; who therefore cannot chuse but to have different Ideas of the same Substance, and therefore make the signification of its common Name very various and uncertain. (lII.ix.13)

Let us assume, however, that we have uniformly discovered twenty properties to belong to the nominal essence of Gold. A parcel of Gold, let us say, is a body which is Fl' F 2, F3 •••F20 • Locke's next point is that each of these discoverable properties has an equal right to be included in the nominal essence of gold, but that for the sake of convenience and for the purposes of communication, we only take a relatively small subset of these properties to comprise its nominal essence. Thus he writes in ill. vi.29 that "men generally content themselves with some few sensible obvious Qualities; and often, if not always, leave out others as material, and as firmly united, as those they take." The problem with this, he argues, is that there is no rational basis for choosing some of these to be included in the nominal essence but not others: each of them has an equal right to be included in the nominal essence. And since there is no rational basis for selecting some of these properties over others, we will invariably make this selection differently, resulting once again in different nominal essences. For these reasons, Locke takes the formation of complex ideas of substances to be radically underdeterrnined by nature, and largely governed by a selection process which is driven by our various interests, abilities, resources and activities. And this, he thinks, is precisely why our ideas of substances are so different, and why we are so often in disagreement about the classification of a particular object. In m.vi.35 he gives an example in which two men possess abstract ideas of gold which differ by a single property: the one includes malleability in his nominal essence of gold, the other does not. He subsequently raises the following question: "Should there be a body found, having all the other properties of Gold, except Malleableness, 'twould, no doubt, be made a question whether it were Gold or no; i.e. whether it were of that Species ." His solution to this query runs as follows: This could be determined only by that abstract Idea , to which every one annexed the name Gold: so that it would be true Gold to him, and

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Here Locke contend s that there is no objective fact of the matter as to whether or not this body belongs to the species gold, since it is we who determine the species of things, and not nature. Thus, he writes that it will be gold for the one, but not for the other. With the addition of this last point, Locke 's critique of essentialism is complete. First, he maintains that there is no uniquely valid way of sorting things into kinds, since he thinks that nature does not sort things into kinds at the micro-structural level, but rather that it is we who do the sorting, and indeed that we do so in a manner which is largely determined by our various interests, activities, and conventions. He also maintains that objects can have essential properties only relative to a given sort or kind, since we cannot intelligibly divorce questions about an object's essential properties from questions about what sort of thing this object is. Locke 's antiessentialism follows from the conjunction of these two positions. Taken together, these positions imply that the properties which are essential to an object on one set of sortal concepts will not be essential to it on other, equally legitimate sets of sortal concepts. And this precludes an object from having any de re essential propertie s, i.e., properties which on object has necessarily, independently from how it is characterized. As an illustration of this point, let us return to the case in which two men possess concepts of gold which differ by a single property. Let '51' stand for the first person, and '52' for the second. And let 'G 1' stand for 5 1' s concept of gold (which includes the property of malleability), and let 'G2 ' stand for 5 2 's concept of gold (which includes all of the properties in G 1 except malleability). Now let us suppose that 51 and 52 encounter a malleable body B which they both take to be an instance of gold. That is, suppose that 51 correctly takes B to be an instance of GJ, while 52 correctly takes B to be an instance of G 2• We can now raise the following question: is B essentially malleable? As in the previous case, on Locke's view is there is no objective fact of the matter, so we cannot intelligibly say that (or ask whether) B is essentially malleable , per se. The most we can say is that it is essentially malleable qua GJ, but not qua G2• And since this result could presumably be repeated for any of B's qualities, and indeed for any properties of any body, his general critique of essentialism follows directly .

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IV. LOCKE ON KINDS AND PARTICULARS

On at least two occasions I have suggested that there is an inherent tension in Locke's rejection of essentialism. While he is a realist about naturally occurring objects, he is not a realist about the biological or chemical species into which these objects are allegedly sorted. In other words, he thinks that nature comes to us objectively divided into discrete particulars, and he denies that nature also divides these particulars into objectively existing species. The tension between these two positions becomes manifest when we add his contention that essential properties can only be attributed to an object relative to a given species. Given his rejection of realism concerning species, this contention precludes him from being a realist about the essential properties of these objects. And this means that he is a realist about particular objects, but not about the properties which are necessary for their existence. Perhaps Locke's situation is not that unusual. It may well be that most of us are in this position. For starters, I suspect that most of us are realists about artifacts, in the sense that we take them to exist independently of what anyone thinks, wants or perceives. And yet if we are pressed on the matter, I doubt if we will embrace the thesis that these objects are sorted, by reality, into objectively existing kinds. Consider the items which one could typically find in a hardware store. While these objects are typically sorted into kinds in terms of the function for which they were designed, it would not be hard to sort them in other ways. Thus, for example, we could sort them in terms of some secondary function (axes and hammers, for example, could be classified as weapons). Alternatively, we could sort them by shape, size, weight, or chemical composition. And while some of these systems of classification will be more useful than others, it seems obviously false to say that there is just one "right" way of sorting these objects into kinds, which is just to say that artifacts are not sorted, by nature, into real species. Moreover, for reasons which we have already considered, I contend that Locke is right in thinking that questions about essences and essential properties are inextricably bound to questions about kinds. Recall the case of unknown object-in-the-box which we referred to as Fred. Apart from knowing what kind of thing Fred is, we cannot even begin to determine whether it is essential to Fred to be partly composed of carbon atoms or to have an internal temperature of less then 32 degrees Fahrenheit. Suppose that Fred would be classified by most people as a hammer. If we also agree, as I think we must, that there is no objective fact of the matter about what sort of thing Fred is, then we must conclude that there is no objective fact of the matter with regard to which of Fred's properties belong to Fred

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essentially. And this puts us in the awkward position of being realists about Fred, but not about the properties which are essential to Fred 's existence. So perhaps the tension which I am claiming to be inherent in Locke's rejection of essentialism is not that unusual. Even so, metaphysically speaking, it is not an ideal situation to be in. For while I do not think that there is contradiction involved in being a realist about particulars but not about their essences, I am convinced that we would be better off either embracing realism on both counts, or anti-realism on both counts. For as we shall see in the next chapter, it will be hard to avoid a contradiction once we start thinking of objects as persisting beings, and in particular, as objects which persist through change.

3

LOCKE'S THEORY OF IDENTITY

The first edition of the Essay was published in the December of 1689. Locke was not content to leave the Essay as it was, for he actively sought out suggestions which could be incorporated into a second edition. From his correspondence it is clear that he was particularly interested in securing comments from William Molyneux. In one of his many letters to Molyneux in this regard, Locke asked if he could suggest any additional topics under the headings of logic or metaphysics (no. 1592, iv:627). Molyneux responded by suggesting that Locke "insist more particularly and at Large on £ternte Veritates and the Principium Individuationis" (no. 1609, iv:650).\ By his own admission, Locke's now famous chapter "Of Identity and Diversity" was written solely in response to the latter half of this suggestion. In the penultimate paragraph of his reply to Molyneux on 23 August 1693, he writes: You will herewith receive a new chapter Of Identity and Diversity, which, having writ only at your instance, 'tis fit you should see and judge of before it goes to press. Pray send me your opinion of every part of it. (no. 1655, iv:722)

It is important to note that Molyneux's request is a very broad one, and that

Locke responds accordingly. That is, he begins this chapter by developing a general theory of identity, which he subsequently applies to various kinds of entities. As Edwin McCann has recently pointed out, there has been relatively little discussion of Locke's general theory of identity (1987, 54). If the first several sections of ILxxvii are discussed at all, they are usually treated as a mere window dressing for Locke's theory of personal identity, which is taken to be the real focus of the chapter. With McCann, I contend that this approach gets things backwards. In this chapter I attempt to set things aright by focusing exclusively upon Locke's general theory of identity. In Part One I discuss his concept of identity, and I begin by discussing what he takes to be its psychological I Locke 's letter (no. 1592) is dated 20 January 1693; Molyneux's response (no. 1609) is dated 2 March 1693.

55 C. H. Conn (ed.), Locke On Essence and Identity © Kluwer Academic Publishers 2004

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origin . I subsequently discuss his use of this concept, in both synchronic and diachronic statements of identity. In Part Two I discuss Locke's principle of individuation, and why he claims this principle to be "existence it self'. In Part Three I discuss Locke 's requirement that identity be "suited to the idea ,"z and the related claim that our difficultie s with this relation are largely due to "the little care and attention used in having precise Notions of the things to which it is attributed" (§ I). In the first section of part three I argue that this claim reflects his observation that sorts of changes which we think an F can undergo and still continue to exist are largely determined by our concept of an F. In the second section I consider whether this view involves the relative identity thesis, and I argue that it does not. And finally in Part Four I argue that Locke's theory of identity is compatible with two very different accounts of what it is for an object to exist at different times, namely, one which states that objects persist by enduring through time in their entirety, and one which states that objects persist by being temporally extended. 1. LOCKE'S CONCEPT OF IDENTITY

I. The psychological origin of this concept

As Molyneux suggests, Locke does touch upon the topic of identity in the first edition of the Essay, e.g., at LivA and II.i.12 (1609, iv:650). But as Curley has so clearly argued , there are serious difficulties with Locke 's first edition treatment of identity (1982, 302-14). For one thing, although he contends (in Liv.3-5) that the idea of identity is not innate, he makes no attempt to account for its origin. Perhaps because he is himself aware of this lacuna, he begins his chapter on identity with just such an account: "Another occasion , the mind often takes of comparing, is the very Being of things , when considering any thing as existing at any determin'd time and place, we compare it with it self existing at another time, and thereon form the Ideas of Identity and Diversity" (§ I). According to Locke, we form the idea of identity by taking notice of the fact that the thing which was in one place p] at t ] is the thing which is in Pn at t2' By mentioning a case in which we succeed in reidentifying an object, he gives the impression that forming the idea of identity involves correctly judging the thing which was in p] at t] to be the thing which is in Pn at t2. But surely this is a mistake, since the same This phrase occurs in Locke' s subtitle to §7 of Locke' s chapter on identity, "Of Identity and Diversity" (ILxxvii). Unless otherwise noted, all references to particular sections of the Essay should be understood as references to sections to this chapter. Some references will also include page numbers from the Nidditch edition of the Essay. 2

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idea of identity is involved in both correct and incorrect judgments of this form. Locke does not explicitly account for the origin of our concept of diversity. Perhaps he feels no need to state the obvious point that once we have the idea of identity, we can form the idea of diversity by negating an identity-statement. That is, we form the idea of diversity by taking notice of the fact that the thing which was in PI at tl is not the thing which is in Pn at t2· Locke's account of the origin of this idea seems to accord an essential role to the passage of time. Thus in giving this account, he might seem to be endorsing Hume's contention in the Treatise "that the view of anyone object [at a single time] is not sufficient to convey the idea of identity" (liv.2:200). I doubt that he would rigidly maintain this thesis, however. For as I shall argue in the next section, Locke does not share Hume's thesis that "we cannot, in any propriety of speech, say, that an object is same with itself, unless we mean , that the object existent at one time is the same with itself existent at another" (liv.4:201). Hence it would seem that there is a way of forming the idea of identity which does not involve the passage of time. Certainly the passage of time is not essential to forming the idea of di versity. Indeed, the clearest cases of numerical diversity are those which involve distinct objects at a single time. And if we can derive the idea of diversity through the negation of an identity-statement, we should similarly be able to derive the idea of identity through the negation of a diversitystatement. In other words, we can form the idea of identity by entertaining the thought that the thing which is F is not distinct from the thing which is

G. 2. Diachronic and synchronic identity-statements Here I intend to develop two important contrasts between Locke and Hume on the concept of identity. I begin by discussing the abovementioned fact that unlike Hume, Locke finds synchronic identitystatements to be both intelligible and unproblematic. I subsequently discuss the fact that unlike Hume, Locke thinks that diachronic identity-statements regarding mutable objects have a chance of being true. From Locke's account of the origin of our idea of identity, Gary Wedeking concludes that Locke takes 'identity' to be "an essentially temporal concept, expressing a relation which obtains exclusively between objects at different times" (1990, 181). That is, Wedeking contends that Locke's concept of identity is relegated exclusively to diachronic statements of identity, statements in which an object exi sting at one time (in its entirety) is said to be identical with an object which exists at another time.

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In support of this claim, Wedeking points out that Locke never uses 'identity' in connection with an object at an instant (1990, 181f). Although Wedeking does not make this connection, the thesis he is attributing to Locke is pretty clearly advocated by Hume , who argued that considering a single object at a single moment of time conveys the idea of unity rather than that of identity, and that the relation of unity is incompatible with the relation of identity (I.iv.2 :200). While it is true that Locke never uses 'identity' in connection with an object at an instant, it is also irrelevant. For on several occasions he affirms that at any single moment an object is the same with itself. "When therefore we demand, whether any thing be the same for no," he writes in § I, "it refers always to something that existed at such a time in such a place, which 'twas certain, at that instant, was the same with it self and no other." Earlier in the same section he expresses this point somewhat differently: "When we see any thing to be in any place in any instant of time, we are sure, (be it what it will) that it is that very thing, and not another, which at that same time exists in another place. " And in §3 Locke applies this claim to a particular kind of entity, namely, an atom. It is evident, he writes, "that considered in any instant of its Existence, it is, in that instant, the same with it self. For being, in that instant, what it is, and nothing else , it is the same, and so must continue, as long as its existence is continued: for so long it will be the same, and no other." From this passage it is clear that he takes the relation of sameness which an atom bears with itself at any moment to be the same relation which an atom bears with itself at different moments . It is also clear that Locke (like nearly everyone) takes 'same' to be synonymous with 'identical'. " Hence, the fact that he is willing to speak of an object's being the same with itself at anyone moment indicates that he does not take identity to be a relation which obtains solely between objects at different times. And for this reason I conclude that he does not share Hume 's contention that "we cannot, in any propriety of speech, say, that an object is same with itself, unless we mean, that the object existent at one time is the same with itself existent at another (Liv.4:201)." Though Locke does not find synchronic identity-statements to be problematic, perhap s he should have. For while he clearly takes identity to be a relation, elsewhere in the Essay he maintains that "there can be no relation , but betwixt two Things, considered as two things." (II.xxv.6). "The Nature therefore of Relation," he writes in II.xxv.5, "Consists in the referring, or comparing two things , one to another; from which comparison, one or both comes to be denominated." The fact that this point occurs in

For additional evidence to this effect, compare Locke' s use of 'sameness' and ' identity' in !.ivA.

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each of his initial drafts of the Essay shows this to be no mere afterthought on Locke's part. Thus in §20 of Draft A he writes: Relation therefor I thinke is the Agreeing or disagreeing of two or more things one with an other in any way wherein they are capable of being compared. In all relation though there be but one word commonly used to expresse it there is included the two things which are compard one with an other & the occasion or ground of that comparison. (35)

Similarly in §98 of Draft B he writes: I take relation to be any way of compareing or considering two things togeather & giveing one or both of them some appellation from that comparison or sometimes giveing even the relation its self a name. (218f)

On this account of relations, the dyadic relation Rab is well-conceived only if 'a' and 'b ' refer to numerically distinct entities . Given that Locke also takes identity to be relation, he might well have anticipated the sort of dilemma raised by Hume in the Treatise : One single object conveys the idea of unity, not that of identity. On the other hand, a multiplicity of objects can never convey this idea...since then both number and unity are incompatible with the relation of identity, it must lie in something that is neither of them . But to tell the truth, at first sight this seems utterly impossible. Betwixt unity and number there can be no medium; no more than betwixt existence and non-existence. After one object is suppos 'd to exist, we must either suppose another also to exist, in which case we have the idea of number: Or we must suppose it not to exist, in which case the first object remains a unity. (Liv.2:200)

Why might Locke have anticipated this dilemma? The answer is simple: both horns of this dilemma are rooted in the assumption that the relation of identity, like all relations, necessarily involves more than one object." This explains why Hume thinks that considering a single object cannot convey the idea of identity, but only of unity . It also explains why he thinks that in order to arrive at the notion of identity, we must suppose this object to be related to another object, which is in turn incompatible with the concept of identity. Although Hume does not explicitly make this assumption , there are a number of texts which suggest that he does hold it. In the first paragraph of I.iii.2, for example, Hume mentions three relations, identity, spatio-temporal location, and causation . Hume subsequently writes that "all kinds of reasoning consists in nothing but a comparison, and a discovery of those relations, either constant or inconstant, which two or more objects bear to each other."

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What might have led both Locke and Hume to make such an assumption? I suspect that this assumption arises out of the fact that they are both primarily interested in dyadic relations. We can safely assume that they both took notice of a formal characteristic of such relations, to wit, that that dyadic verb phrases such as '_ is taller than _ ' and '_ is the same age as , have two argument places. Thus, they see that for a dyadic verb phrase to be built up into a complete sentence, it needs to be completed by two noun phrases. This observation, in turn, seems to have prompted them into thinking that dyadic relations can only obtain between two objects. This may in part be due to the fact that most of the relations with which Locke and Hume were concerned are irreflexive. But since some dyadic relations are not irreflexive, such as the one expressed by ' _ is the same age as _', it is a mistake to assume that dyadic relations can only obtain between more than one object. Once we drop this assumption, moreover, it turns out both (i) that unity can be a relation, and (ii) that the relations of unity and identity are compatible, since they are also equivalent. That is, once we reject this assumption we can say without contradiction that Cicero and Tully are one and the same, since 'Cicero is Tully' is equivalent to 'Cicero and Tully are one' . Locke is evidently not aware of the tension between his assertion that identity is a relation and his assertion that relations must involve two or more objects. If this problem had been pointed out to him, I suspect that he would have responded by disavowing the second of these assertions. In support of this claim, I would like to point out that he sometimes makes a slightly weaker claim about the nature ofrelations. In II.xxv.6, for example, he suggests that the relata must either be distinct entities, or else they must be considered as distinct entities. Thus he writes that "there must always be in relation two Ideas, or Things, either in themselves really separate, or considered as distinct, and then a ground or occasion for their comparison.t" Here Locke suggests that a relation can obtain between the objects a and b, even though they are not really distinct, but are merely considered as distinct. Surely Locke does not think that judging a single object to be related to itself requires one to engage in an act of self-deception. That is, he does not think that considering one object as two requires one to suppose that (or act as if) this object really is two, when he knows that it is not. Neither does he think that considering a single object as two requires one to unknowingly fall into error: judging an object to be related to itself does not require one to This passage is taken directly from the Section 98 of Draft B, where Locke writes "Soe that to Relation it is necessary that there should be two things or Ideas either in them selves realy seperate or considerd as distinct & then some ground or occasion for their comparisons, or quality wherein they agree or differ" (218t) . 5

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falsely believe that it is two. Rather, considering one thing as two involves nothing more than thinking of a single thing under two different descriptions, descriptions which provide a basis for comparing a thing with itself. And this is precisely what he does when he writes that "another occasion the mind often takes of comparing, is the very Being of things, when considering any thing as existing at any determin'd time and place, we compare it with it self existing at another time, and thereon form the Ideas of Identity and Diversity" (§ 1). According to Locke , we can judge an object to be identical with itself by thinking of it as occupying one place at one time and as occupying a place at some other time. In some respects Hume 's solution to the above problem is like the one I think Locke would have given, if it had been proposed to him. For one thing, Hume's solution also depends upon the passage of time. "To remove this difficulty," Hume writes, speaking of the above dilemma, "let us have recourse to the idea of time or duration" (Liv.2:200). According to Hume, we arrive at the idea of identity through a "fiction of the imagination," whereby an object is supposed to exist for period of time without change . Thus Hume: 'tis only by a fiction on the imagination, by which the unchangeable object is suppos 'd to participate of the changes of the co-existent objects, and in particular of that of our own perception s. This fiction of the imagination almost universally takes place; and t'is by means of it, that a single object, plac'd before us, and survey'd for any time without discovering in it any interruption or variation, is able to give us a notion of identity. (Liv.2:20 1)

Through this fiction of the imagination, Hume thinks, we arrive at the idea of identity. With this idea, moreover, Hume thinks he can slip through the horns of the above dilemma: Here then is an idea, which is a medium betwixt unity and number; or more properly speaking, is either of them, according to the view, in which we take it: And this is the idea we call that of identity. We cannot , in any propriety of speech, say, that an object is the same with itself, unless we mean, that the object existent at one time is the same with itself existent at another. By this means we make a difference, betwixt the idea meant by the word, object, and that meant by itself, without going the length of number, and at the same time without restraining ourselves to a strict and absolute unity. (Liv.2:20l)

The passage of time provides us with an object a at one time and with an object b at a later time. Through a fiction of the imagination we (falsely) suppose that a is able to persist through time without interruption or variation, which, in tum , enables us to (falsely) suppose that a is b.

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In writing that "we cannot, in any propriety of speech, say, that an object is the same with itself, unless we mean, that the object existent at one time is the same with itself existent at another," one might take Hume to be implying that some statements of the form 'the thing which is F at tl is the thing G at t2' are true." But unlike Locke, Hume does not think that any statements of this form are capable of being true, at least if our domain is restricted to common sense objects such as cats, cabbages and kings. For as we shall see more clearly below, Hume thinks both that the passage of time implies variation, and that variation between two objects is incompatible with their being numerically identical. On a closer inspection of this passage, moreover, it is clear that he is not concerned with the truth of such statements, but only with the canons of acceptable speech. For although he believes that all statements of this form are false, he nevertheless thinks that there are times at which it is appropriate to utter them. By now it should be clear that there is at least one very important distinction between Locke and Hume with respect to diachronic identitystatements: unlike Locke, Hume thinks that identifying the object which was in PI at tl with the object which is in Pn at tz will always involve one in error, since it requires one to falsely suppose the continued existence of an unchanging object. As we shall see in what remains of this chapter, Locke thinks that the plant, animal or person which was in PI at tl can be numerically identical with the plant, animal or person which is in Pn at t2, in spite of the fact that the passage of time inevitably results in changes of various sorts. In part two I develop his general account of the conditions under which the thing which is F at one time can be the thing which is G at another time. II. LOCKE'S PRINCIPLE OF INDIVIDUATION

In § I of his chapter on identity Locke suggests that our concerns about identity only extend to those objects which exist in both space and time," Thus he writes that "when therefore we demand, whether any thing be the same or no, it refers always to something that existed such a time in such a place, which was certain, at that instant, was the same with it self and no other." According to Locke, there is a deep conceptual connection between a thing's identity and its spatio-temporal existence, as evidenced by his statement in §3 that the principium individuation is is "Existence it self'. Despite its cryptic nature, the underlying meaning of this statement is Thus Bennett (1971, 336). Hence like Hume and unlike Frege, Locke is not concerned with the identity of abstract objects such as numbers and propositions. 6

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relatively simple: Locke says that his principle of individuation is existence itself, since he thinks that each object is distinguished from every other (of its kind) by the time and place at which it first began to exist, and indeed by its spatial location at every subsequent moment of its existence.

1. Locke 's argumentfor the principium individuationis As I shall interpret him, Locke takes his principle of individuation to follow from three subordinate principles which I shall refer to as (i) the exclusion principle, (ii) the single place principle, and (iii) the single beginning principle . Briefly, the first of these principles states that no two objects of the same kind can occupy the same region of space at the same time. The second states that no object can occupy more than one region of space at anyone time. And the third states that there is a single , determinate time and place at which each object first began to exist. I shall consider each of these principles in turn. First, let us consider the exclusion principle, a principle which he claims to be incapable of doubting . "For we never finding, nor conceiving it possible, that two things of the same kind should exist in the same place at the same time," he argues in § I, "we rightly conclude, that whatever exists any where at any time, excludes all of the same kind, and is there itself alone." In §2 he gives some indication of what he means here by 'kind'. We have ideas, he writes, of but three sorts of substances: God, finite spirits, and bodies. Locke subsequently applies the exclusion principle to each of these kinds of substances. Thus Locke writes that "though these three sorts of Substances, as we term them, do not exclude one another out of the same place; yet we cannot conceive but that they must necessarily each of them exclude any of the same kind out of the same place". It is important to note that for Locke, the exclusion principle is true by definition when applied to material bodies. For in the chapter entitled "Of Solidity," Locke takes material bodies to be solid bodies, which he defines as those things which fill space in such a way as to exclude any other solid bodies from also occupying this space (ll.iv.l). "Solidity," Locke writes in ll.iv.4, "consists in repletion, and so an utter Exclusion of other Bodies out of the space it possesses". Since material bodies are solid, it follows by definition that no two material bodies can occupy the same region of space at the same time. That the exclusion principle is true by definition for Locke when applied to material bodies helps to explain why he finds this principle to be indubitable. But he seems equally confident that it is impossible for two immaterial spirits to occupy the same place at the same time. As Wedeking

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points out, this view calls into question Locke's justification for ascribing solidity solely to corporeal substances: Locke claims of course that solidity is "essential to Body" and is "no where else to be found or imagin'd , but only in matter" (Il.iv.l ). But except for the question begging reference in his account of filling space to the exclusion of other solid bodies, it would seem that the notion of "solidity" could be applied to mental as much as material substance. For according to the exclusion principle, both have the capacity to exclude objects of the same kind; neither excludes objects of the other kind. Therefore both mental and material substance would appear to "fill space" in precisely the same way. Solidity, therefore, is nothing but the exclusion principle as applied to material substance. But since the exclusion principle applies to mental substances as well, solidity, given Locke's understanding of the term, is hardly suitable to play a very significant role in distinguishing bodies from spirits. (1987, 20)

That is, apart from Locke's "question begging" claim that solidity "consists in repletion, and so an utter Exclusion of other Bodies out of the space it possesses" (TI.ivA, italics mine), it would seem that immaterial spirits are no less solid than corporeal substances. If he had said that solidity "consists in repletion, and so an utter Exclusion of other Substances out of the space it possesses," then he would have been committed to attributing solidity to both corporeal and incorporeal substances. According to Wedeking, Locke's application of the exclusion principle to mental substances commits him to the view that mental and corporeal substances fill space in exactly the same way. Against Wedeking, I contend that Locke is not committed to this view, since he is not committed to view that mental substances fill space at all. In TI.xv.11, for example, he claims not to know if mental substances take up space in the same way as corporeal substances. Thus he writes that "what Spirits have to do with Space, or now they communicate in it, we know not. All that we know is, that Bodies do each singly possess its proper portion of it, according to the extend of its solid Parts ; and thereby exclude all other Bodies from having any share in that particular portion of Space, whilst it remains there." Earlier in the Essay Locke argues that spirits are located in space, since "they cannot operate, but where they are" (TI.xxiii .19). And since mental substances can be located in space, he thinks that mobility can be attributed to mental substances as well as to bodies. Given that "Spirits do operate at several times in several places," he argues, "I cannot but attribute change of place to all finite spirits" (§ 19). But even if we grant that mental substances are located in space, it does not follow that they are capable of filling space, for mathematical points have a spatial location without having spatial extent.

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And in his discussion of mobility Locke encourages us to think of mental substances as analogous with mathematical points. "If a Mathematician can consider a certain distance, or a change of that distance between two Points," he argues , "one may certainly conceive a distance, or a change of that distance between two Spirits; and so conceive their Motion, their approach, or removal, one from another" (§19) . His analogy between mental substances and mathematical points, I contend, strongly suggests that he takes mental substances to have a spatial location, without having spatial extent. As we have seen, Locke takes mental substances to be located in space, and in particular, to be located where they act. And while he takes bodies to act on other bodies by impulse, he thinks that mental substances act on bodies by thought (II.xxiii.29). Thus Locke's application of the exclusion principle to mental substances is warranted only if he has reason for thinking that two (finite) mental substances cannot simultaneously act upon the same body . It seems to me, however, that he is not in a position to rule out this possibility, since he confesses to be completely ignorant of how a single mental substance is capable of acting on a body by thought. I contend, therefore, that Locke's application of the exclusion principle to mental substances is unjustified. In §2 of his chapter on identity Locke offers a reductio argument which begins by denying an instance of the exclusion principle. If we suppose it to be possible for particles of matter to occupy the same space at the same time, he contends, "the Notions and Names of Identity and Diversity would be in vain, and there could be no such distinction of Substances, or any thing else from another." Locke's argument runs as follows: Could two Bodies be in the same place at the same time; then those two parcels of matter must be one and the same, take them great or little; nay, all Bodies must be one and the same. For by the same reason that two particles of Matter may be in one place, all Bodies may be in one place: Which, when it can be supposed, takes away the distinction of Identity and Diversity, of one and more, and renders it ridiculous. But it being a contradiction, that two or more should be one, Identity and Diversity are relations and ways of comparing well founded, and of use to the Understanding.

There has been almost no discussion of this argument in the contemporary literature. Indeed, the only direct discussion of this argument that I have found is in a recent article by Martha Brandt Bolton (1994) . While Bolton finds it difficult to see just what this argument amounts to, she makes the following suggestion:

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possible that the universe have a place. The line of reasoning would be that if two bodies can cohabit a place, then there is nothing to prevent all bodies [from] cohabiting the same place, but that this is impossible for no place can be assigned to the totality of things . (1994, 109)

As an interpretation of the above argument, this will clearly not do. For in his discussion of place at II.viii. I0 Locke does not suggest that the idea of place for the universe is contradictory, but only that we cannot have this idea. And even if it is contradictory, it is evidently not the contradiction which Locke has in mind in the above argument, since assigning a place to the universe as a whole is not inimical to the distinction between identity and diversity. I would like to suggest that the above passage contains two distinct reductio arguments with a shared set of premises. The first argument concludes that two numerically distinct bodies are identical, since these bodies are capable of occupying the same region of space at the same time. The second argument concludes that all numerically distinct bodies are identical, since if there is no reason why two bodies cannot occupy the same space at the same time, then there is no reason why any number of bodies cannot occupy the same space at the same time. Since this is the only substantive difference between the two arguments, I shall restrict my attention to the first. This argument runs as follows : (1) a is a body, and b is a body. (2) a is distinct from b. It is possible for a and b to occupy the same region of space at the (3) same time. Assumed (4) If it is possible for a and b to occupy the same region of space at the same time, then a is identical with b. (5) a is identical with b. (3,4) (6) Therefore, a is both distinct from and identical with b. (2,6) (7) Therefore, it is not possible for a and b to occupy the same region of space at the same time. (3,6) Given that the premises of this argument (1-4) entails a contradictory conclusion (6), Locke validly concludes that (3) is false. But clearly (4) is as least as controversial as (3). Why does Locke think that (4) is true? I contend that Locke does not question the truth of (4) because he is tacitly presupposing the truth of the exclusion principle. As evidence to this effect, I would like to point out that (4) depends upon the following universal statement:

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(4')

(For any two objects of the same kind x and y) if it is possible for x and y to occupy the same region of space at the same time, then x is identical with y. This statement, moreover, is merely the converse of the exclusion principle: (4") (For any two objects of the same kind x and y), if x is identical with y, then it is not possible for x and y to fail to occupy the same region of space at the same time. On my interpretation, Locke's pair of reductio arguments are valid, but unpersuasive. For Locke fails to give a non-question-begging reason against following Leibniz in inferring the denial of (4) instead of (3). 8 Now while all deductively valid arguments are question-begging in the trivial sense that the conclusion of the argument is contained in the premises, on this interpretation Locke's argument depends upon an implicit premise which very nearly is the conclusion. Jonathan Bennett has (in correspondence) suggested a different explanation of Locke's reductio. On Bennett's interpretation, this argument stems from his account of identity through time for an atom, "i.e., a continued body under one immutable Superficies" (§3). In accordance with this description of an atom, he takes Locke's account of diachronic identity for atoms to be conducted in terms of the integrity through time of a surface: the atom a (which is in PI at t1) is the atom b (which is in Po at t2) if and only if (i) a and b have the very same size and shape and (ii) a and bare spatio-temporally continuous in a way that constantly preserves this size and shape. From this account of identity through time for an atom, Bennett suggests, Locke 's reductio proceeds as follows : If two atoms could be colocated in space and then come apart again, there would be no fact of the matter about which was which, i.e., about whether the one that entered the combine from the south is the one that left it heading north or rather the one that left it heading south. And if two could be colocated, then so could any number; from which it follows that it could happen that all the world 's atoms were colocated so that there would be no fact of the matter about the identification of any atom before the collapse with any atom after it.

Now this argument is superior to the one which I have attributed to Locke in at least one important respect: it does not beg the question. As Bennett points out, however, it is not a very good argument against colocation, since it doesn't rule out the possibility of colocation. Rather, it only shows that if colocation were actual, then identification across it would not be possible. 8 In II.iv.l of the New Essays Leibniz writes that although it is true "that bodies are reluctant jointly to occupy a single place. Yet some people are not convinced that this reluctance is unconquerable" (123).

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In other words, this argument shows that our ability to identify atoms across

time depends upon the fact that colocation does not actually occur, which is compatible with the fact that colocation could occur. I have serious reservations about the adequacy of this interpretation. In the first place, Bennett's paraphrase commits Locke to a gross non sequitor. For Locke clearly thinks that his argument does rule out the possibility of colocation . That is, he thinks he has shown that if two bodies could be colocated, then they would have to be one and the same, which "takes away the distinction of Identity and Diversity...and renders it ridiculous". If Bennett has adequately represented the core of Locke's reductio, then this argument is patently invalid. If this were the only difficulty with Bennett 's paraphrase, however, we wouldn't have significant reason for rejecting it in favor of the one I have offered, which takes this argument to be valid, but boring and impersuasive. Bennett's interpretation at least has the virtue of not making Locke guilty of presupposing the truth of the conclusion. Rather, the conclusion is alleged to follow from a substantive thesis about the identity through time for an atom. I think that there is a potentially more serious objection to Bennett's reconstruction of Locke's reductio: in his original statement of this argument Locke is not concerned with reidentifying two atoms after a putative instance of colocation. Rather, he says that if two distinct atoms a and b were to be colocated, then these atoms would be one and the same. This is not a point about the reidentification of either a or b at some later time, but rather about their identity at a single moment of time, viz. the moment at which they become colocated. Moreover, the conclusion which Locke draws from this possibility is much stronger than the one Bennett attributes to him. According to Bennett, the possibility of colocation entails that there is no subsequent fact of the matter as which atom is a and which is b. But Locke seems to think that there would be a definite fact of the matter, at least while they are colocated, to wit, that they would be numerically identical, which he rightly takes to be impossible. Because he takes this to be a contradictory state of affairs, he does not pursue it further, i.e., he does not consider the identity of atoms which have ceased being colocated. For these reasons, I do not think that Bennett's interpretation adequately represents the core of Locke's argument, even if it is philosophically more interesting than the one which I have attributed to him. So much for the exclusion principle. Let us now consider the single place principle, i.e., Locke's contention that no object can exist in more than one place at anyone time. In § I he states these two principles in the same breath. It is impossible, he writes, "for two things of the same kind, to be or exist in the same instant, in the very same place; or one and the same thing in different places." It is not difficult to see why he needs this principle: he

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wants to conclude that each existing object 0 is distinguished from every other object (of its kind) at any time t by the particular region of space which 0 occupies at t. Thus Locke writes that it is "Existence it self, which determines a Being of any sort to a particular time and place incommunicable to two Beings of the same kind" (§3). Should 0 be capable of existing in different places at the same time, then there would not be a unique way of distinguishing 0 from every other object of its kind. Now we normally say that an object exists in a given place in virtue of the fact that one of its parts exists in this place. Thus, for example, we don't think that it is necessary for a stick to be entirely submerged in body of water for it to be in the water: we only require that some part of it is in the water. Does this commit us to denying the single place principle? Not if we take this principle to preclude an object from occupying discrete regions of space. Since this is the most natural reading of the single place principle, I shall assume that it is the one which Locke embraces. Notice, moreover, that this reading does rule out the existence of scattered objects, i.e., objects whose parts occupy disjoint regions of space at any given time ." In setting forth the single place principle, I suspect that Locke is mostly concerned with ruling out the possibility that a non-scattered object can occupy more than one region of space at a single time. For Locke intends for the single place principle to support his single beginning principle, according to which there is a single, determinate time and place at which each object first began to exist. For if a (non-scattered) object can only exist in one continuous region of space, then it can only come into existence in one region of space. Locke's principium individuationis does not merely state that each object is marked off from every other (of its kind) at t by the region of space which it occupies at t. It also states that each object is marked off from every other (of its kind) at all times by the particular time and place in which it first came into existence. Thus he writes: "that therefore that had one beginning is the same thing, and that which had a different beginning in time and place from that, is not the same, but diverse" (§I) . In §2 he applies this conclusion to mental substances: "finite spirits having each its determinate time and place of beginning to exist, the relation to that time and place will always determine to each of them its Identity as long as it exists." With the addition of the single place principle, Locke is in a position to demonstrate this point. Since no two objects of the same kind can exist in This reading best explains Locke's contention that a mass of atoms cannot survive the removal of any of its parts. Had he allowed for the possibility of scattered objects, then Locke would have had to make a stronger claim, to wit, that a mass of atoms cannot survive the annihilation of any of its parts. See James Van Cleve' s discussion of the three grades of mereological essentialism (1986,141-56).

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the same region of space at the same time, then two objects of the same kind cannot come into existence in the same region of space at the same time. And since for each object there is exactly one time and place in which this object first came into existence, it follows that each object is individuated from every other object of its kind by this time and place. It is frequently argued that Locke' s statement that no object can have more than one beginning of existence is intended to rule out the possibility that a thing can have a "gappy" or intermittent existence. In other words, his contention that "one thing cannot have two beginnings of Existence" is taken to require that the existence of an object must exhibit spatio-temporal continuity. 10 Clearly this position reflects a different reading of this statement, to wit, that an object cannot come into existence at two different times. Although this is a plausible reading of Locke ' s statement, it faces one very serious objection: on this reading, Locke 's argument for the principium individuationis is invalid. II For if he takes the single beginning principle to state that an object cannot come into existence at two different times, then the single beginning principle does not follo w from his single place principle , according to which an object cannot occupy two discrete regions of space at any one time. With Hoffman and Bolton, I contend that the context of Locke ' s argument for the principium individuationis demands the alternative reading of single origin principl e, according to which there is a single time and place at which each object first began to exist. Clearly this principl e does not tell against the possibility of a thing' s having an intermittent existence. But neither does it support this possibility. It is important to point out, moreover, that he never explicitly says that persisting object s, as such, must exhibit temporal continuity. Indeed, this requirement appears not to be even an implicit part of his general theory of identity. For as we shall see in more detail below, he does not think that persons must exhibit temporal continuity. 12 In §23 of his chapter on identity he explicitly argues that consciousness is able to "unite remote Existences into the same Person". He evidently thinks that the one and the same person s can exist at both t1 and at a later time t3, even though s does not exist at an intermediate time t2. Assuming that his account of personal identity is consistent with his general theory of identity (as we ought, without compelling evidence to the contrary), then the requirement of temporal continuity cannot be an implicit 10 Thus C. D. Broad (195 1, 59); Robert Coburn (1971, 52); J. L. Mackie (1976, 141); Paul Helm (1979, 175); Edwin McCann (1987, 59); Gary Wedeking (1987, 22f); and Michael Ayers (199 1, 2:208f). 11 Thus Joshua Hoffman (1980, 107-9) and Martha Brandt Bolton (1994, 127n.21). 12 This has been noted by Margaret Atherton (l984b, 284), Edwin McCann (1987, 74), Vere Chappell (1990, 30) and Jonathan Bennelt (1994, 114).

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part of his general theory of identity, even if it does figure into his account of identity for other kinds of entities . As I have interpreted him, Locke's statement that the principium individuationis is existence itself amounts to this: each object which exists is set apart from every other object of its kind by the time and place at which this object first began to exist, and indeed by every subsequent moment of its existence. This account affords him with a general account of the conditions under which an object at one time is identical with an object at another: "That therefore that had one beginning is the same thing, and that which had a different beginning in time and place from that, is not the same but divers." Thus according to Locke, the atom (spirit) a which was in PI at tl is the atom (spirit) b which is in P2 at t2 if, and only if a and b came into being in the same place at the same time. 2. Three objections

According to C. D. Broad, Locke's principle of individuation is "completely futile in practice and by no means satisfactory in theory" (1951 , 16). It is futile in practice, he contends, because "we do not know whether particles begin to exist in the course of nature at all. And, even if we did know this, we do not know where or when any particular particle originated." That is, Broad contends that this principle is futile practice because we do not have access to the alleged times and places at which objects such as atoms first come into existence, and we obviously cannot make any use of this account without this information. Broad does not merely contend that it is difficult-if not impossible--to apply this principle. He also contends that unnecessary to do so. For, he writes, In order to show, e.g., that the two descriptions ' the particle which occupied at tl' and 'the particle which occupied S2 at t2' apply to one and the same entity, you would have to show with regard to each of them that it applies to the same entity as a certain description of the form 'the particle which originated at So at to' . Now I cannot imagine any way in which you could show this which could not equally be used directly to show that the two descriptions ...apply to the same entity. It seems to me that the criterion must in any case be the presence or absence of a certain kind of spatial and qualitative continuity, bridging the gap between the two places in question during the period between the two moments in question. I cannot see why this criterion should not be applied directly to the gap between Sl and S2 and the period between tl and t2 without dragging in a reference to a date and place of origin. (1951, 17)

s"

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Suppose we want to know whether the atom a, which was in PI at t), is the atom b, which is in P2 at t2. On Broad's reading, Locke would instruct us to trace each back to its point of origin , in order to determine whether a and b have the same point of origin. Surely he is right in taking this procedure to be unnecessarily complicated, since it would suffice merely to trace b back to t" in order to determine whether b exists in PI at this time . How might Locke have responded to Broad's first criticism, that we are simply not able to apply Locke's principle of individuation in many cases? I suspect that Locke would have begun by agreeing with Broad's contention, especially in the case of atoms. But I don't think that he would have taken this to pose a problem for his theory. For he nowhere suggests that we will ever be in a position to use this principle to determine whether the atoms a and b are identical with one another. More importantly, in the first two sections of his identity chapter-when he is attempting to establish his principle of individuation-he is not interested in providing us with epistemic criteria for reidentification. Indeed, he does not begin to provide us with this sort of information until the middle of §3, where his goal has clearly shifted from establishing the truth of this principle to applying this principle to particular sorts of cases. Thus, his first objective is to provide us with a general account under which the F which was in PI at tl is the F which is in Pn at t2. There are two crucial features of this account: first, he takes statements of this form to be objectively true or false, and second, he claims to have discovered the condition which must obtain for statements of this form to be true: the F which was in PI at tl and the F which is in Pn at t2 must have come into existence in the same time and place . The fact that we are not always in a position to know whether these conditions obtain, on the other hand, does not seem to be problematic for Locke. How might Locke have responded to Broad's contention that his theory is unnecessarily complicated? One again , I suspect that he would have begun by conceding Broad's point that it would be sufficient to trace b back to t" in order to see whether b occupies PI at this time. For though he frequently emphasizes that each object is individuated by the time and place at which it first came into existence, he readily grants that each object is individuated by the time and place in which it exists at every moment of its existence. Thus, for example, in § 1 he writes: For we never finding, nor conceiving it possible, that two things of the same kind should exist in the same place at the same time, we rightly conclude, that whatever exists any where at any time, excludes all of the same kind, and is there it self alone. When therefore we demand, whether any thing be the same or no, it refers always to

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something that existed such a time in such a place, which 'twas certain, at that instant, was the same with it self and no other.

And again in §3 he writes: From what has been said, 'tis easy to discover, what is so much enquired after, the principium lndividuation is, and that 'tis plain is Existence it self, which determines a Being of any sort to a particular time and place incommunicable to two Beings of the same kind.

Once more, I do not think that Broad has provided us with a telling objection to Locke's general theory of identity. For in seeking to determine whether the F which was in PI at t l is the F which is in Po at t2, he would surely grant that it would be sufficient to trace the latter F back to tlo in order to determine whether it exists in PI at this time. Hence contrary to Broad's objection, his theory does not require us to trace each back to its time and place of origin. It seems to me that there is an even more serious objection lurking in this passage from Broad. We want to know whether the atom a (which was in PI at tl) is the atom b (which is in P2 at t2)' How would Locke propose to answer this question? On Broad's reading, Locke would simply instruct us to trace a and b back in time, in order to see if a and b came into existence at the same place and time. This procedure is intended to supply us with a criterion for determining whether the atom a is the atom b. In other words, Locke's instructions are intended to provide us with the persistence conditions for an atom. But we can follow these instructions only if we already know how to trace an atom back in time, and hence only if we already know what these persistence conditions are. Thus, Locke's account appears to be viciously circular. For it presupposes precisely what it is suppose to explain, namely, an understanding of the conditions under which an atom can exist at successive times. I contend that this argument rests upon an inadequate understanding of the manner in which Locke applies his principle of individuation to particular cases. For as we shall see in part three, he does not think that he can derive the persistence conditions for particular sorts of things from his (exceedingly general) principle of individuation. Nor does he think that he can apply this principle directly to particular objects, i.e., in a manner which not mediated by sortal concepts. Instead, he maintains that we can apply this principle to an atom only by paying close attention our concept of an atom, since the persistence conditions which we assign to an atom are determined by this concept.

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III. IDENTITY AND THE IDEAS OF THINGS

In part one of this chapter I observed that Locke thinks that one and the same object can exist at different times , even though the passage of time will inevitably be accompanied by a change in this object' s properties. In part two I developed Locke' s principle of individuation, a principle which provides Locke with a general account of the conditions under which the thing which was in PI at tl is the thing which is in Pn at t2. According to this principle, the former is identical with the latter if and only if (i) they are of the same kind, and (ii) they first began to exist in the same place at the same time. Let us now turn to the one remaining element of his general theory of identity, namely, his contention that accurate judgments of identity depend upon careful attention to the ideas of the things to which this relation is applied. It is possible that Locke takes this contention to be something of an innovation.F For he sugge sts that heeding this admonition will remove the darkness which has hitherto shrouded this relation with obscurity. Thus in § 1 he writes that "that which has made the Difficulty about this Relation, has been the little care and attention used in having preci se Notions of the things to which it is attributed." He makes similar claims on at least two other occasions: 'Tis not therefore Unity of Substance that comprehend s all sorts of Identity, or will determine it in every Case: But to conceive, and j udge of it aright, we must consider what Idea the Word it is applied to stands for: It being one thing to be the same Substance, another the same Man , and a third the same Person, if Person, Man , and Substance are three names standing for three different Ideas; for such as is the Idea belonging to that Name, such must be the Identity: Which if it had been a little more carefully attended to, would have prevented a great deal of that Confusion, which often occurs about this Matter, with no small seeming Difficulties. (§7) ...the difficulty or obscurity, that has been about this Matter [of identity] , rather rises from the Names ill used, than from any obscurity in things themselves . For whatever makes the specifik Idea , to which the name is applied , if that Idea be steadily kept to, the distinction of any thing into the same , and divers will easily be conceived , and there can arise no doubt about it. (§28)

If so, then he is probably mistaken. For something very like this contention appears in Hobbes' chapter "Of Identity and Difference" in his Elements of Philosophy Concerning Body, which first appeared in 1655. 13

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Although Locke takes the suggestion that "identity is suited to the idea" to be a helpful one, this is perhaps the most confusing aspect of his general theory of identity. At first glance, it is not at all clear what this claim amounts to." As a result, these passages have been subject to widely divergent interpretations. On some accounts, this claim simply reflects his observation that the sorts of changes which we think an object can undergo and still continue to exist are a function of the idea which we associate with this object. On other accounts, this claim is taken to indicate that 'identity' is ambiguous, and that there are different kinds of identity. On this reading, there is one sort of identity which is applicable to horses, and another which is applicable to masses of atoms . Some of those who advance this claim, moreover, contend that Locke takes identity to be relative in the (Geachian) sense that a and b can be the same horse, but different masses of matter. I shall begin by defending the first of these accounts, after which I shall discuss the contention that Locke endorses the relative identity thesis.

I. General ideas and persistence conditions As I have already suggested, I contend that Locke's suggestion that "such as is the Idea ...such must be the Identity" reflects his observation that the sorts of change which we think that an object can undergo and still continue to exist are determined by the sortal concept which we associate with this object. In order to see this, we need only examine how Locke applies his general account of identity to particular kinds of things. Consider the following passage from §3: From what has been said, 'tis easy to discover, what is so much enquired after, the principium individuationis , and that 'tis plain is Existence it self, which determines a Being of any sort to a particular time and place incommunicable to two Beings of the same kind. This though it seems easier to conceive in simple Substances or Modes; yet when reflected on, is not more difficult in compounded ones, if care be taken to what it is applied.

Locke clearly takes his principle of individuation to be applicable to all positive entities, whether substances or modes, simples or compounds. Indeed, he seems to think that applying this account of identity to compound substances and modes is no more difficult than applying it to simples, "if care be taken to what it is applied". That is, he suggests that in order to apply this general account of identity in particular cases we need to pay careful attention to what it is that we are applying this account to, and

14

Thu s Alston and Bennett (1988 , 32t) and Bolton (1994, 112).

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perhaps because he is an indirect realist this involves examining the ideas which are associated with a thing. Locke subsequently illustrates this point with an example: he applies his principle of individuation to an atom, and he begins by recounting his idea of an atom, namely, "a continued body under one immutable Superficies, existing in a determinate time and place." With this idea in hand, he proposes the following account of identity for atoms. Of an atom, he writes, 'tis evident, that, considered in any instant of its Existence, it is, in that instant , the same with it self. For being, at that instant, what it is, and nothing else, it is the same, and must continue, as long as its Existence is continued: for so long it will be the same, and no other.

Alston and Bennett rightly find this account to be uninformative. Locke's explanation, they write, "tells us that an atom continues to be the same atom as long as its existence is continued. Undeniable, but hardly illuminating. For any x whatever, x continues to be the same x so long as x continues to exist" (1988, 32). What Alston and Bennett fail to point out is that in the conclusion of his chapter on identity Locke extends this apparently trivial account of identity to all positive entities . Thus in §28 he writes : To conclude, whatever Substance begins to exist, it must, during its Existence, necessarily be the same: Whatever Compositions of Substances begin to exist , during the union of those Substance, the concrete must be the same: Whatsoever Mode begins to exist, during its Existence, it is the same: And so if the Composition be of distinct Substances, and different Modes, the same Rule holds.

Given that Locke here affirms Alston and Bennett's general conclusion that for any x, x continues to be the same as long as x continues to exist, what prevents Locke's application of identity to these objects from being altogether trivial? What rescues his treatment of identity from triviality, I contend, is precisely his observations (i) that some kinds of objects are capable of existing through changes which are sufficient to annihilate other kinds of objects, and (ii) that the sorts of changes which an object can undergo and still continue to exist are determined by the kind to which this object belongs. As we shall see, Locke places careful limits on the changes which an object can undergo if it is to continue to exist, limits which are provided by the general idea which we associate with this object. It is sometimes suggested that Locke's contention that "identity is suited to the idea" indicates that he takes 'identity' to be ambiguous, in such a way that one sense of 'identity' is applicable to persons, while a different sense is applicable to organisms." Given Locke's concluding remarks in §28, I take 15

Thus Anthony Flew (1951, 53f), Henry Allison (1966, 42f), J. L. Mackie (1976, 141),

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this reading to be untenable. For as this passage indicates, he takes 'identity' to be univocally applicable to different kinds of things. In other words, Locke does not think that there are as many kinds of identity as there are kinds of things. Rather, he thinks that there is one relation of identity, such that the relation which an atom or an oak tree bears to itself is the same relation which a person bears to himself. Though Locke does not think that there are different kinds of identity for different kinds of things, he does think that there are different criteria of identity for different kinds of things. In other words, he thinks that the conditions under which an atom at t1 is identical with an atom at t2 will be substantially different from the conditions under which a dog at t1 is identical with a dog at t2. I have already noted his treatment of identity for atoms. In order show how these criteria can vary, let us briefly consider his treatment of identity in the cases of masses of atoms, organisms, and persons. Of the first category he writes: If two or more Atoms be joined together into the same Mass, every one of those Atoms will be the same, by the foregoing Rule: and whilst they exist united together, the Mass, consisting of the same Atoms, must be the same Mass, or the same Body, let the parts be never so differently jumbled: But if one of these Atoms be taken away, or one new one added, it is no longer the same mass, or the same Body (§3).

According to Locke, the identity of a mass of atoms is a function of the identity of its parts. Suppose a given mass of atoms m is composed of the atoms aJ, a2, and a3. He thinks that if we know what it is for each of these atoms to exist at different times, then we can easily see what is required for m to exist at different times: m continues to exist so long as it continues to be composed of aJ, a20 and a3, i.e., so long as these and only these atoms continue to "exist united together". Locke takes it for granted that masses of atoms exist, and that they are subject to various kinds of changes, some of which are compatible with their continued existence, and some of which are not. Moreover, he thinks that the changes which are compatible with m's continued existence are dictated by our concept of a mass of atoms. For he goes on to suggest that any sort of change which is compatible with aJ, a2, and a3's being continuously united together is compatible with the continued existence of m. Thus, he writes that aJ, a20 and a 3 can change position relative to one another and still continue to compose m. Though he does not mention other sorts of change

David Behan (1979, 59t), and Christopher Fox (1988 , 30).

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which are compatible with m' s continued existence, presumably he could have. Locke mentions two sorts of changes which are not compatible with the continued existence of m. He contends that if either (i) any of these atoms should cease to be connected with the others, or (ii) an additional atom a4 should be annexed to this concretion, then m will cease to exist, and a new mass of atoms will have come into existence. In short, his idea of a mass of atoms is that of a collection of atoms, a collection which possesses its constituent parts essentially. The manner in which its parts are arranged, however, is a contingent feature of a mass of atoms. Consequently, he takes the mass of atoms which is composed of al and a2 to be numerically distinct from the mass which is composed of aJ, a2 and a3, which is likewise distinct from the mass which is composed of aJ, a2, a3 and a4. It has been suggested that Locke's statement that a mass of atoms continues to exist "whilst they exist united together" indicates that he takes persisting masses of atoms-like the atoms themselves---to exhibit temporal continuity. On this account, the mass mJ, which was in rl at tJ, is the mass m2, which is in rz at t2, if and only if (i) ml and m2 are composed of precisely the same collection of atoms, and (ii) there exists a mass which is exactly composed of these atoms at every moment in time between t l and t» Thus, on this account it is not sufficient merely for these masses to be composed of the same atoms. For suppose that ml and m2 are both entirely composed of the atoms a, b, and c. If at some time between tl and t2, either (i) one of these atoms should become separated from the other two, or (ii) a fourth atom d should become attached to a, b, and c. then ml would cease to exist. Should either of these actions be reversed just prior to t2 (thus forming m2), the requirement of spatio-temporal continuity precludes ml from coming back into existence. Hence, if persisting masses must exhibit temporal continuity, then there can be numerically distinct masses which are composed of exactly the same atoms. It is not obvious that Locke requires persisting masses to exhibit temporal continuity, however. In the case of atoms, this requirement is built into the very concept of an atom: an atom, for Locke, is "a continued body under one immutable superficies." Not so in the case of masses. A mass is simply "a Cohesion of Particles of Matter any how united" (§4), which exists "whilst they exist united together". This latter statement, moreover, is not nearly strong enough to warrant the conclusion that he requires persisting masses to exhibit temporal continuity, for nothing in this statement prevents ml from resuming its existence upon the reversal of the actions mentioned in (i) or (ii) . Hence if it is not necessary for persisting masses to exhibit

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temporal continuity, then it is not possible for numerically distinct masses to be composed of entirely the same atoms. I submit that in working out his treatment of persistence for masses, Locke was simply not concerned with the sorts of cases mentioned in the previous two paragraphs, i.e., cases in which a mass begins to exist at to, ceases to exist just after tz. and resumes its existence just before t3. Moreover, I contend that he has no reason to question the possibility of such cases . In particular, one should not suppose that Locke's contention that "one thing cannot have two beginnings of existence" (§ I) can do any work for him here. For as we have just seen, he does not take this statement to imply that a thing cannot come into existence at two different times, but rather that a thing cannot come into existence in two different places at the same time." Thus, his contention that an object cannot have two beginnings of existence is compatible with a thing's having a "gappy" or intermittent existence. Locke subsequently discusses the sorts of changes which are compatible with the continued existence of organisms, and he begins by making the following observation: in the state of living Creatures, their Identity depends not upon a Mass of the same Particles; but on something else. For in them the variation of great parcels of matter alters not Identity: An oak, growing from a Plant to a great Tree, and then lopp'd, is still the same Oak: and a Colt grown up to a Horse, sometimes fat, sometimes lean, is all the while the same Horse: though, in both these Cases, there may be a manifest change of the parts. (§3)

That is, he begins by observing that the sort of change which is incompatible with the continued existence of a mass of atoms is compatible with the continued existence of an organism, since an organism continues to exist despite the fact that it is composed of different particles of matter at different times. Since masses of matter and organisms are both composed of material particles, Locke is forced to explain why only the latter are capable of gaining and losing parts. He does this by comparing the idea of a mass of matter with the idea of an organism, which in the following case happens to be an oak: We must therefore consider wherein an Oak differs from a Mass of Matter, and that seems to me to be in this; that the one is only the Cohesion of Particles any how united, the other such a disposition of them as constitutes the parts of an Oak; and such an Organization of

16

See above, p. 70.

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CHAPTER THREE those parts, as is fit to receive, and distribute nourishment, so as to continue, and frame the Wood, Bark, and Leaves, etc. of an Oak, in which consists the vegetable Life. (§4)

In short, he contends that organisms are capable of gaining and losing parts because an organism is not a body whose parts "are any how united", but rather a body whose parts are organized in a way that is capable of sustaining physiological processes such as nourishment and respiration without which the organism cannot continue to be alive . Indeed, given the nature of these physiological processes, it would seem to be essential to the continued existence of a plant or animal that it be capable of gaining and losing parts. Given this concept of an organism, Locke contends that an organism continues to exist only if its parts continue to be organized in a way that is sufficient to sustain these physiological processes. Thus Locke: That being then one Plant, which has such an Organizationof Parts in one coherent Body, partaking of one Common Life, it continues to be the same Plant, as long as it partakes of the same Life, though that Life be communicated to new Particles of matter vitally united to the living Plant, in a like continued Organization, conformable to that sort of Plants. For this Organization being at anyone instant in anyone Collection of Matter, is in that particular concrete distinguished from all other, and is that individual life, which existing constantly from that moment both forwards and backwards in the same continuity of insensibly succeeding Parts united to the living Body of the Plant, it has that Identity, which makes the same Plant, and all the parts of it, parts of the same Plant, during all the time that they exist united in that continued Organization, which is fit to convey the Common Life to all the Parts so united. (§4) For Locke, an organism cannot continue to exist if the organization of its parts breaks down to a degree which is sufficient to interrupt any vital physiological processes. Thus, while an organism can continue to exist without the capacity to reproduce, it cannot continue to exist without the ability receive nourishment from its environment. Locke also thinks that persons are capable of existing at different times, and with different properties. And as with both masses of atoms and organisms, his concept of a person dictates the changes which he thinks a person can undergo and still continue to exist. Thus he writes in §9 that if we are 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 it self as it self, the same thinking thing in different times and places." For Locke, a person is a thinking (and

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therefore conscious) being which is capable of existing at different times only if it is conscious of itself as existing at these times. Thus he writes: since consciousness always accompanies thinking, and 'tis that, that makes every one to be, what he calls self; and thereby distinguishes himself from all other thinking things, in this alone consists personal identity, i.e. the sameness of a rational Being: And as far as this consc iousness exte nds backwards to any past Action or Thought, so far reaches the Identity of that Person; it is the same self now it was then; and ' tis by the same self with this present one that now reflect on it, that that Action was done. (§9)

It has frequently been pointed out the role which is played by sameness of life in the case of organisms is analogou s to that which is played by sameness of consciousness in the case of person. 17 For ju st as he thinks that the organism which was in P I at t1 is the organism which is in Pn at t: if and only if the two share the same life, he thinks that the person who was in PI at tl is the person which is in Pn at t2 if and only if the two share the same • 18 consciousness. The foundat ion of Locke 's general theory of identity is his principium individuati on is, i.e., his contention that objects are individuated by the time and place at which they first came into existence. According to this principle, the object which was in P I at t l is the object which is in Pn at tz if and only if (i) they belong to the same kind, and (ii) they came into existence in the region of space at the same time. In the present section I have attempted to explicate another feature of Locke' s theory, i.e., his doctrine that "identity is suited to the idea". As I have interpreted him, this doctrine reflects his observation that the changes which an object can undergo and still continue to exist are dictated by the general idea which we take this object to exemplify. Through this observation, he is able to apply his principle of individuation to various kinds of things. For suppo se we want to know whether the F which was in PI at tl is the F which is in Pn at t2' It is clearly not enough to know that they are identical if and only if they share a common origin: before we can determine this we must we must know whether the changes which the former has undergone are compatible with the continued existence of an F. On Locke' s account , these conditions are supplied by our idea of what it is to be an F. 17 Thus Paul Helm (1979, 317); Margaret Atherton (1983, 94); Edwin McCann (1987, 681); William Uzgalis (1990, 292); and Michael Ayers (1991, 2:221). 18 Clearly there is much more to be said about Locke's treatment of identity in the cases of masses, organisms and persons. Since I am presently concerned with developing Locke' s genera l treatment of identity, I shall defer further discussion of these issues to the following chapters.

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As we saw in the preceding chapter, Locke does not think that there is an ontologically privileged set of sortal concepts, i.e., a set of concepts which correctly identifies the objective divisions which occur between natural1y occurring species. For Locke does not think that nature ranks things into kinds or species. Rather, he thinks that it is we who sort things into kinds, and indeed that we do so in a way that is largely determined by human interests, abilities and conventions. Consequently, he thinks that there are many, equal1y legitimate ways of ranking things into sorts, and hence that there are many, equally legitimate sets of sortal concepts. As we have just seen, sortal concepts play an important role in Locke's theorizing on identity, for he argues the kinds of changes which we think an object can undergo and still continue to exist are largely determined by the sortal concept (= general idea) which we associate with this object. Moreover, in his identity chapter he employs a relatively small number of sortal concepts, namely, his concept of an atom, a mass of atoms, a plant (oak), an animal (horse, man), and a person. The question at hand, then, is this: is his general doctrine that identity must be "suited to the idea" inextricably tied to these sortal concepts, or does it work equally well with other sets of concepts? That is, does he think, for example, that accurate judgments of personal identity depend upon careful attention to his concept of a person, or merely upon any (adequately formed) concept of a person? The following passages provide us with Locke's answer: I know that in the ordinary way of speaking, the same Person, and the same Man, stand for one and the same thing. And indeed everyone will always have a liberty of speak, as he pleases, and to apply what articulate Sounds to what Ideas he thinks fit, and change them as often as he pleases. But yet when we will enquire, what makes the same Spirit, Man, or Person, we must fixt the Ideas of Spirit, Man, or Person, in our Minds; and having resolved with our selves what we mean by them, it will not be hard to determine, in either of them, or the like, when it is the same, and when not. (§ 15) Whatever makes the specifik Idea, to which the name is applied, if that Idea be steadily kept to, the distinction between any thing into the same, and divers will be easily conceived, and there can arise no doubt about it. (§28)

In both of these passages Locke concedes that our judgments of identity may well involve sortal concepts which are different from the ones he employs. He only requires that we employ our concepts consistently, thus he writes in § 15 that the meaning of our general ideas must be "fixt", and in §28 that these ideas must be "steadily kept to". This shows that Locke is not

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helping himself to natural kind terms in is his identity chapter, as has sometimes been argued, " but rather that he is making use of artificial kinds. 2. Locke and the relative identity thesis

Since Locke clearly thinks that our judgments of identity may involve different sortal concepts, and also that the contents of these concepts will determine the outcome of these judgments, surely he also thinks that the judgments of the form 'the F in PI at tl is the F in Pn at t2' will be true on some values of 'F' and false on others. This suggests, in tum, that he would agree with Geach's and Wiggins's contention that statements such as 'a at tl is (identical with) b at t2' are incomplete, and must be relativized to some sortal count noun as in 'a is the same F as b'.z° According to Geach, without the presence of a sortal qualifier (implicit or otherwise), the expression 'a is b' "is just a vague expression of a half-formed thought" (1967 ,3). David Wiggins has pointed out that there are two versions of the relative identity thesis, a weak version , which he refers to as D, and a strong version, which he refers to as R. Both versions make the above insistence that meaningful identity-statements must contain (implicitly or explicitly) a sortal count noun. But R involves the additional claim that it is possible for two objects to be identical relative to one sortal, but not relative to another, i.e., the possibility that a and b may be the same F, but different G's. I have just argued that Locke does indeed endorse the weaker version of this thesis . Let us now consider whether he also endorses the stronger version, which I shall henceforth refer to simply as the relative identity thesis. I contend that Locke is not committed to the relative identity thesis , and indeed that he would have decisively rejected it. Nevertheless, I think that his relationship to this position deserves serious attention. For in the first place, the list of philosophers who ascribe this thesis to Locke is an impressive one." Indeed, for the better part of two decade s after being initially proposed by Geach, this seems to have been the predominant interpretation of Locke's contention that "identity is suited to the idea"." Thus Anthony Flew (1951, 65). See Wiggins (1967,1 ) and Geach (1967, 3). 21 Thus Peter Geach (1967, 11); Douglas Odegard (1972, 38); E. J. Borowski (1975, 277); Bruce Langtry (1975, 402); J. L. Mackie (1976, 160); David Wiggins (1976, 142n.23); Nicholas Griffin (1977, 131); Edwin Curley (1982, 312); Udo Thiel (1983, 40-42); Christopher Fox (1985, 37); C. J. F. Williams (1989, 83); and Gary Wedeking (1990, 17981). 22 Only recently has this interpretation been subject to serious challenge, for example, by Alston and Bennett (1988), Vere Chappell (1989), William Uzgalis (1990), and Mark Thornton (1991). 19

20

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This explains why, as early as 1974, Bruce Langtry is able to assert , without argument, that Locke "is the most prominent advocate of the view that there are cases in which an object x is the same F as an object y but x is not the same G as y" (1974, 401f), and why, as late as 1990, Gary Wedeking is similarly able to assert that attributing the relative identity thesis to Locke is the "usual way" of interpreting Locke's "idea relativism" (1990, 179). There is perhaps an even more compelling reason for taking this interpretation seriously: attributing this thesis to Locke is no mere anachronism, as has sometimes been suggested. After all, Hobbes and Boyle--Locke's most prominent fellow corpuscularians-both speak in a manner which seems to involve the relative identity thesis, for both of them speak of objects as ceasing to exist on some specifications, but not on others. Thus in De Corpore (1655) Hobbes writes that philosophers like himself, who "tie themselves to natural reason," suppose that a body can neither be generated nor destroyed, but only that may appear otherwise than it did to us, that is, under different species, and consequently be called by other and other names; so that that which is now called man, may at another time have the name of not-man. (Part 2, Ch. 7, Sect. 21; p. 66)23

Here Hobbes suggests that an object may cease being a cat or a man without ceasing to exist, simpliciter, which suggests, in tum, that he has a notion of relative perishing. Later in the same work Hobbes makes a similar claim : We must consider by what name anything is called, when we inquire concerning the identity of it. For it is one thing to ask concerning Socrates, whether he be the same man, and another to ask whether he be the same body; for his body, when he is old, cannot be the same as when he was an infant, by reason of the difference of magnitude. (Part 2, Ch. II , Sect. 7; p.8S)

Boyle makes a similar suggestion in The Origin of Forms and Qualities According to the Corpuscular Philosophy (1666) : A body is said to be generated, when it first appears clothed with all those qualities upon whose account men have been pleased to call some bodies stones, and others metals, and others salts, &c., so, when a body comes to lose all or any of those accidents that are essential and necessary to the constituting of such a body, it is then said to be corrupted or destroyed, and is no more a body ofthat kind, but loses it title to its former denornination...and though the body be still a body (no natural agent being able to annihilate matter), yet it is no longer

23

Quotations from De Corpore are taken from the edition by Mary Calkins (1989) .

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such a bodl as it was before, but perisheth in the capacity of a body of that kind?

Like Hobbes, Boyle seems to be suggesting that an object can cease to exist relative to one specification without ceasing to exist, simpliciter. That is, an object a ceases to exist qua F when it ceases to have the properties which we take to be essential to an F, but nothing prevents a from continuing to exist qua G. At least at first glance, then, it appears that Hobbes and Boyle are both committed to the relati ve identity thesi s. For they both seem to ha ve a notion of relative persi stence and perishing , which will inevitably give rise to instance s in which a and b are the same G' s, but different F' s. Since Locke is greatly indebted to the work of Hobbes and Boyle, this, in tum, forces us to take seriously the claim that Locke' s theorizing on identity was informed by this thesis. I would like to offer two responses to this line of reasoning. First, even if Hobb es and Boyle do seem to relati vize persistence in this way, there is little reason to think that Locke follow s their lead. For as Ayers points out , he never speaks of relati ve perishing or corning-to-be (1991 , 2:320n.17). The closest he comes, Ayers suggests, is the followin g: All Thing s, that exist, besides their Author, are all liable to Change; especially those Things we are acquainted with, and have ranked into Bands, under distinct Names or Ensigns. Thus that, which was Grass to Day, is to Morrow the Flesh of a Sheep; and within a few days after, becomes part of a Man: In all which, and the like Changes, 'tis evident, their real Essence, i.e. that Constitution, whereon the Properties of these several things depended, is destroy'd , and perishes with them. (ill.iii.19: 419)

With Ayers, I contend that this does not amount to an endorsement of relative perishing . For surely Locke is not saying that there is an x which is a blade of grass on Monday, a Sheep (and hence not a blade of grass) on Tue sday, and a Man (and hence neither a sheep nor a blade of grass) on Friday. Instead, he seems to be suggesting that some of the material corpuscles which partly compose a blade of grass on Monday might belong to a sheep on Tue sday and to a man on Frida y. Second, I contend that Boyle, at least, doe s not actually think that thing s-i.e., real, substantial things-perish relati ve to some specifications even though they persist relative to others. For elsewhere in The Origin of Forms and Qualiti es Acco rding to the Corpuscular Philosophy he gives what I take to be a more complete description of his position :

24

Quoted from the edition of Boyle 's works by M. A. Stewart (1979, 45t).

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CHAPTER THREE Now a body being capable of any other qualitie s besides those whose convention is necessary to make up its form, the acquisition or loss of any such quality is by naturalists, in the strict sense of the at term, named alteration, as when oil comes to be frozen , or to change colour, or to grow rancid; but if all or any of the qualities that are reputed essential to such a body come to be lost or destroyed, that notable changes is called corruption: as, when oil being boiled takes fire, the oil is not said to be altered in the former sense, but corrupted or destroyed, and the emergent fire generated ....But neither in this or in any other kind of corruption is there anything substantial destroyed (no such thing having been produced in generation, and matter itself being on all hands acknowledge incorruptible) , but only that special connexion of the parts, or manner of their co-existence, upon those accounts the matter , whilst it was in its former state, was, and was called, a stone or a metal, or did belong to any other determinate species of bodies. (1991, 52f)

Here Boyle maintains that cases involving the destruction of material solids such as stones, pieces of metal or portions of oil do not amount to cases of substantial corruption, which implies that such objects are not themselves substances, even though they are composed of material corpuscles which presumably are. But what are such things as stones or ice cubes, if not substances? This passage suggests that Boyle takes such apparently substantial, persisting objects to be modes of their constituent, atomic parts. That is, an event which might seem to involve the annihilation of a substance-e.g., the melting of an ice cube-involves nothing more than a change in the "special connexion" of its parts and in the "manner of their coexistence" . Thus, Boyle, at least, is not committed to a relativistic account of persistence, since he does not take these putatively persisting objects in question to be real, substantial entities. Now it is sometimes suggested that the relative identity thesis should not be attributed to Locke since he does not explicitly make any statements of the form "a and b are the same F, but different G's". But while I agree with Alston and Bennett's contention that "nothing in the 'Identity' chapter comes close to having the form 'x is the same F as y but is not the same Gas y' ''(1988, 27), I also think that several of Locke's statements in this chapter can easily be paraphrased into statements of this form, statements which I shall refer to as Rvstatements." Thus, I can readily understand why some take the following statement from §3 to contain statements of this form: An Oak, growing from a Plant to a great Tree, and then lopp'd, is still the same Oak: And a Colt grown up to a Horse , sometime fat, sometimes lean, is all the while the same Horse: though , in both these 25

Here I follow Uzgalis (1990,296n.6).

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Cases, there may be a manifest change of parts: So that truly they are not either of them the same Masses of Matter, though they be truly one of the same Oak, and the other the same Horse.

In this passage , Locke seems to make the following pair of claims : (1) The seedling and the mature tree are the same Oak, but different Masses of Matter; and (2) The colt and the horse are the same Horse, but different Masses of Matter. Other passages can be taken to express similar claims . Thus in § 15, he seems to say that (3) The Prince and the Cobbler are the same Person, but different Men. 26 And similarly in §23 Locke seems to say that (4) The Day Man and the Night Man are the same Man, but different Persons ." While it is granted on all hands that these are not well-formed R-statements, we can easily paraphrase them into statements which are. Thus, if Locke advocates the relative identity thesis, he ought to accept the following : (1') The seedling is the same Oak as the mature tree, but the seedling is not the same Mass of matter as the mature tree, although the seedling is a mass of matter, and the mature tree is a mass of matter. (3') The Prince is the same Person as the Cobbler, but the Prince is not the same Man as the Cobbler, although the Prince is a man, and the Cobbler is a man. (4') The Day Man is the same Man as the Night Man, but the Day Man is not the same Person as the Night Man, although the Day Man is a person , and the Night Man is a person. According to the relative identity interpretation, Locke takes (1), (3), and (4) to be shorthand for (1'), (3'), and (4') . And in (1'), for example, Locke is not merely thought to identify the seedling with the mature tree, he is also thought to identify the seedling with one mass of matter, and the mature tree with another mass of matter. Let 'a ' stand for the seedling, and 'b' for the mature tree, and let 'Ma' and 'Oa' to be short for 'a is a mass of matter', and 'a is an oak '. And finally, read ' a =pb' as 'a is the same F as b', On the relative identity interpretation, Locke is taken to endorse the following claim: (1") [(Oa & Ob) & (a =0 b)] & [(Ma & Mb) & (a:f;M b)]

26 27

See 330: 20-31. See 344:17-25.

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Clearly, if Locke takes (1) to be shorthand for (1'), then he is committed to there being cases in which two individuals are identical relative to one sortal, but not relative to another. But does he ever say that a horse or an oak is a mass of matter? If so, how do we make sense of his statement in §4 that at any given time an organism is constituted by a collection of atoms which are arranged in a suitably complex manner? According to Wedeking, when Locke says that a horse is constituted by a mass of matter, what he means is that the horse is a mass of matter, and that the mass of matter is a horse. Thus Wedeking: When we think of wooden planks, iron nails, and canvas sails, etc., put together in a certain way as constituting the ship, I would suggest that the force is that of 'constitutes' in "an insult to a ruling monarch constitutes lese majeste" The insult, under the right conditions, simply amounts to lese majeste. Similarly, or so we are tempted to think, the collection of parts organized in a certain way is not simply a new collection of parts...it is the ship. (1990, 171)

Taken in isolation, (1'), (3') and (4') appear to be plausible readings of (1), (3), and (4). At issue is whether paraphrasing the latter in terms of the former does violence to Locke's theory of identity. One passage which is frequently taken to be at odds with the relative identity interpretation comes at the end of §3, immediately after the passage quoted above. For the sake of clarity, I shall quote these passages together, highlighting the second: An Oak, growing from a Plant to a great Tree, and then lopp'd, is still the same Oak: And a Colt grown up to a Horse, sometime fat, sometimes lean, is all the while the same Horse: though, in both these Cases, there may be a manifest change of parts: So that truly they are not either of them the same Masses of Matter, though they be truly one of them the same Oak, and the other the same Horse. The reason whereof is, that in these two cases of a Mass of Matter, and a living Body, Identity is not applied to the same thing.

In the highlighted passage, Locke is explaining why the seedling and the mature tree are the same oak, but not the same masses of matter. On one reading of this passage, he is saying that the seeding and the oak tree are not the same masses of matter, because the plant (in both cases) is one thing, and the mass of matter which composes the plant is another. Since they are distinct things, they clearly cannot be identical. Consequently, this reading is incompatible with the relative identity interpretation. For as Uzgalis points out, this interpretation requires that there be some one thing which is characterized both as an oak tree and as a mass of matter (1990, 286).

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The problem with this reading, however, is that it is by no means clear what Locke takes to be the referent of 'thing'. He may be referring to the mass of matter and the oak tree, according to the above translation, or he may be referring to his ideas of these things. Chappell suggests some reasons for preferring the latter possibility: ...in other passages in Chapter xxvii in which he speaks of "applying" identity to something, it is the ideas of things to which he says the identity-s-i.e., the idea of identity-is applied [§ I); in one place [§7] he says that it is applied to a word standing for an idea (of a thing). Locke is of course notorious for his use of thing-language to refer to ideas in the Essay, and for speaking of ideas when he means to refer to their objects; he even takes note of this habit himself at one point [at ILviii.8] (\ 989,72).

Indeed, in II.xxv.9 he suggests that all relations are concerned with our ideas of things. Thus Locke : Though there be a great number of Considerations, wherein Things may be compared one with another, and so a multitude of Relations : yet they all terminate in, and are concerned about those simple Ideas, either of Sensation or Reflection; which I think to be the whole Materials of all our Knowledge.

According to Chappell, Locke may well be referring to his ideas of a mass of matter and of an oak tree, in which case this passage does not tell against the relative identity interpretation. For on this interpretation, Locke is not saying that the oak tree and the mass of matter are distinct entities, but only that their corresponding ideas are distinct. William Uzgalis contends that this passage tells against the relative identity interpretation even if Locke is referring to ideas instead of things. For, Uzgalis contends, the fact that he says that in the two cases "Identity is not applied to the same thing," strongly suggests that he takes there to be a single relation of identity involved in both cases, whereas the relative identity thesis appears to deny this." "Relative identity," Uzgalis writes, "is roughly the doctrine that there is a different kind of identity for each sort of thing, e.g., chair identity is different from giraffe identity. Absolute identity, by contrast, holds that while chairs and giraffes are surely different, the relation of identity is the same everywhere it is found" (1990, 284). As I have already argued, Locke's summation of the chapter in §28 also indicates that he takes there to be a single relation of identity which applies equally and unambiguously to all positive entities . But does the relative identity thesis entail otherwise? Geach seems to think so. According to Geach, this 28

A similar point is made by Nicholas Griffin (1977, 17).

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thesis entails that there are as many kinds of identity as there are kinds of things, i.e., that the relation which obtains between two entities relative to one sortal is different from the relation which obtains between these entities relative to a (substantially) different sortal. Thus in his reply to Feldman (1969) Geach writes: On his very first page Feldman ascribes to me a claim about the relation expressed by 'is identical with'. Feldman's way of speaking is, as Ryle might say, systematically misleading: for of course I deny that anyone relation, even a relative relation (whatever that may be), is the relation expressed by 'is identical with'. My whole thesis [in "Identity"] was that 'is identical with' expressed now one, now another, relation, according to the context of utterance. (1969, 556)

If Geach and Uzgalis are correct in taking the relative identity thesis to have this implication, then Uzgalis' point is a legitimate one. I contend, however, that they are both mistaken: the relative identity thesis does not entail that there are as many relations of identity as there are kinds of things , or that the relation of identity which obtains between two objects relative to one sortal is different from the that which obtains between two individuals relative to a different sortal. Suppose, according to this thesis, both that a is the same F as b, and that a is the same G as b. According to Geach and Uzgalis, the statements 'a is the same F as b' and 'a is the same G as b' express different relations. It is clear, however, that a relative identity theorist can deny this claim, and maintain instead that these statements express the very same relation, but that they involve different relata. For according to the relative identity theory, the relation of identity is a triadic relation, i.e., one which obtains between an object, an object, and a sortal concept. Thus the first statement expresses a relation between a, b and the sortal concept F, while the latter expresses the same relation between these two objects and the sortal concept G.29 Although the relative identity thesis does not entail that 'is identical with' expresses different relations in different contexts, we might still have a basis for distancing Locke from this thesis. For Locke at least writes as if he takes the relation of identity to be dyadic, i.e., a relation which obtains between exactly two things, and not two things and a concept. The problem is that even relative identity theorists are free to write in this manner, since the third, conceptual element of the (relative) identity relation is often supplied contextually. Hence, the fact that Locke seems to treat identity as a dyadic relation is not significant evidence against his being a relative identity theorist.

29

I am indebted to Jonathan Bennett for helping me to understand this point.

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In what remains I shall argue that there is at least one compelling reason for thinking that Locke would have rejected this thesis : it is inconsistent with his principle of individuation.i" Let us suppose, with Locke, that the tree which was planted in my backyard as a seedling in 1965 is the same tree that exists there today. Let us also follow him in supposing that at any given moment, this tree is composed of a mass of atoms, arranged in a suitably complex manner. For the sake of argument, let us stipulate that this tree first came into existence at to, and that at tl, shortly after it was planted , this tree is composed of a mass of matter ml, and that at t2, exactly thirty years after t], this tree is composed of a mass of matter m2. Let 'a' refer to the tree which is composed of m], and 'b' refer to the tree which is composed of m2' Here, then, is a putative case of relative identity: a and b are the same Tree, but a and b are different Masses of Matter. Given the physiological processes involved in being a living organism , we can safely assume that m l is not identical with m2. The debate turns upon whether Locke ever intends to identify the tree with the mass of matter which composes it. As we have seen, if Locke takes the tree to be one thing, and the mass of matter which composes it to be another, then the relative identity interpretation fails. In other words, the viability of this interpretation depends upon whether he is willing to say that a is m], and that b is m2. According to Wedeking, Locke would be willing to make these claims, since he takes 'x is constituted by y' to be synonymous with 'x is identical with y' . In other words, Locke's saying that a is constituted by ml amounts to his saying that a is mI ' Against this interpretation, I contend that he would not have been willing to conclude either that a is m], or that b is m2, and consequently that the relative identity interpretation of Locke's chapter on identity is untenable. For according to his principle of individuation, two objects cannot be identical if they came into existence at different times. Since band m2 came into existence at markedly different times, his commitment to this principle would surely have led him to conclude that b is not identical with mz with respect to any sortal concept whatever. Since Locke's primary reason for writing "Of Identity and Diversity" was to respond to Molyneux 's request that he elaborate upon the principle of individuation, and since the relative identity interpretation is incompatible with his principle of individuation, I contend that the relative identity interpretation should be rejected. There is no indication that Locke confronts the relative identity thesis in his chapter on identity. If he had, I suspect that he would denied that b is mz 30

Versions of this argument are presented by both Chappell (1989) and Uzgalis (1990).

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on the ground s that each of these objects has propertie s which the other lacks. That is, I think that he would have rejected the relative identity thesis not merely because it conflicts with his principle of individuation, but also because it conflicts with the more general principle that if x is F and y is notF, then x is not identical with y. It is important to note, however, that he does not make use of this general principle in his identity chapter, although his principle of individuation is clearly a special case of this principle. IV. DOES LOCKE HAVE A CONSISTENT THEORY OF IDENTITY ?

In the previous two chapters I have argued that there is an obvious tension in Locke's critique of essentialism, inasmuch as he is a realist about particular objects, but not about the properties which are essential to their existence. As I have already suggested in the introduction, the ingredients which give rise to this tension-his realism about particulars and his conventionalism with respect to kinds and essence s-are also present in his theory of identity. Only here, I think, it looks as if these ingredients give rise to a full-blown contradiction. At the risk of being repetitive, let me explain each of these points in tum . First, we can see his realism about particulars at work in his principle of individuation, according to which an object is set apart as an object from every other object by the time and place at which it first came into existence. Indeed , it seems to me that this principle extend s his realism about particulars from a realism about what exists, right now, to a realism about the objective temporal boundaries of these individual s. Second , we can see his conventionalism with respect to kinds and essences at work in his principle that identit y-judgments be "suited to the idea," since he does not require, in practice, that our judgments be suited to his ideas, but rather to our own. Given the manner in which we form these ideas (on this view, at least), they will frequently differ in non-trivial ways. This means, in tum, that the persistence conditions which stem from these ideas will also be different on many occasions . This is where Locke seems to get into trouble. Suppose, once more, that we have significantly different notions of what a cat is, and that we have relied upon these notions to come up with correspondingly different sets of persistence conditions for cats. As a result, you think that poor Tabby has expired, while I think that she is still hanging on for dear life. From the vantage point of his principle of individuation and his realism about particular organisms, Locke must say that there is an objective fact as to whether Tabby still exists. In particular, he must say that exactly one of us right. From the vantage point of his conventionalism with regard to kinds and essences, on the other hand, he cannot consistently make this claim. If

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it makes no sense to speak of "the right account" of what a cat is, then it neither does it make sense to speak this way about the conditions under which cats can continue to exist. So it certainly looks as if Locke is committed to making contradictory claims here. In what remains of this chapter I would like to establish this point in a more systematic manner. 1. Two accounts ofpersistence

Although Locke does have a general theory of sameness or identity, he does not offer a general account of persistence. That is, he does not give an account of what it is for an object of any kind to exist at different times. Rather, he gives a unique account of persistence for each sort of object: he begins by giving an account of what it is for the same atom to exist at different times, and he subsequently gives a distinct accounts for spirits, masses of atoms, organisms and persons. Moreover, his general treatment of identity is compatible with two very different accounts of what it is for an object to exist at different times, an account which states that physical objects persist by enduring through time in their entirety, and an account which states that objects persist by being temporally extended. The first of these accounts takes physical objects to have spatial extent, but not temporal extent. As spatially extended objects, they have as many spatial dimensions as space has; since we (normally) take space to have three dimensions, we take these objects to have three dimensions. But these objects are not temporally extended, i.e., they are not spread out in time in a way that is analogous to their being spread out in space. Rather, the whole object exists wholly and entirely at every moment of its existence. The persistence of a three-dimensional object, moreover, is compatible with this object's changing properties: for at least some values of 'F' , the thing that is F at t1 can be numerically identical with the thing that is not-F at t2. We can say without contradiction that the same thing is both F and not-F because properties are indexical. According to Peter van Inwagen, we are free to think of the indexicality of properties in either of two ways (l990a, 247). That is, saying that an object is F at t1 involves saying either that this object bears the relation of having to the time-indexed property F-at-tt. or else that this object bears a time-indexed relation having-at-r, to the property F. On the second account persistence, physical objects have both spatial and temporal extent. That is, in an addition to having three spatial dimensions, they also have a fourth, temporal dimension. As spatially extended objects, four-dimensional objects have spatial parts in the same way that threedimensional objects do. But in addition to having spatial parts, these objects also have temporal parts. As Heller points out, once we have the concept of a temporally extended object, the notion of a temporal part is no more

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problematic that the notion of a spatial part: a (proper) part of a fourdimensional object 0 is one which is smaller than 0 on at least one of its four dimensions. Whereas a spatial part of 0 is one which is smaller than 0 along at least one of its spatial dimensions, a temporal part of 0 is one which is smaller than 0 along its temporal dimension (1990, 12). Whether we realize it or not, I submit that we all know perfectly well what it is for something to be temporally extended. For we are all familiar with events such as weddings or football games, and events like these are unquestionably endowed with temporal extent. Thus, for example, we all know what a football game is, and part knowing this is knowing that a game "stretches" through a period of time. Should we only happen to see the first half a game, for example, we would not claim to have seen the whole game. Rather, we would claim to have seen part of the game. And even if we did see the whole game, we might still say things like "I liked the second half better than the first". In short, there is no getting around the fact that we take events like football games to have temporal parts, and hence temporal extent, which shows that we have no difficulty grasping these concepts. What is controversial about four-dimensionalism, of course, is not the claim that some things have temporal extent (in addition to having spatial extent), it is rather the claim that such things as oak trees and house sparrows have temporal extent. Indeed, a common objection to this account of objects is that it confuses (enduring) objects with their (temporally extended) life-histories." For the moment I have only two things to say about this objection. First, although some philosophers have explicitly identified objects and events, 32 to say that this identification is based upon a confusion is to beg the question against this account. Second, we can reject the assimilation of objects and events without rejecting the thesis that objects have temporal parts." For even if one thinks that concrete, fourdimensional objects are like events with respect to their having temporal

Thus Peter Geach (1979, 701); David Wiggins (1980, 25n.12); Lawrence Lombard (1986, 127-31); Michael Ayers (1991, 2:102-8, 319n.15); and David Oderberg (1993, 1251). 32 Thus, for example, Quine writes that "physical objects, conceived thus four-dimensionally in space-time, are not to be distinguished from events or, in the concrete sense of the term, processes. Each comprises simply the content, however heterogeneous, of some portion of space-time, however disconnected and gerrymandered" (1960, 171). Similarly, Nelson Goodman writes that "tables, steam yachts, and potatoes are events of comparatively small spatial and large temporal dimensions (1966, 128), and C. D. Broad writes that the only difference between a flash of lightening and the cliffs at Dover "is that the former last for a short time and the latter for a long time"(1923 , 54). See also Richard Taylor (1955, 600). I must add, however, that 1 am reluctant to attribute this thesis to Broad, the above statement notwithstanding. For later in the same chapter Broad concludes that "changes of events cannot be treated like the changes of things" (1923, 64). 33 Thus Paulo Dau (1986, 472n.6). 31

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extent, one might also think that objects and events are not alike in other respects, and hence that objects are not events, simpliciter. If we understand what it is for an object to have temporal extent, then we understand what it is for such an object to exist at different times . For just as we say that a spatially extended object exists in different places in virtue of its having different spatial parts in these places, we say that a temporally extended object is capable of existing at different times in virtue of its having different temporal parts at these times. A similar account is given for qualitative change: for at least some values of 'F', a four-dimensional object can be F at one time and not-F at another in virtue of its having one temporal part which is F and another which is not-F. Now on either of these accounts of persistence, questions about identity through time can be cast in terms of persistence conditions. Thus, for example, if atoms persist by enduring through time in their entirety, then the persistence conditions for an atom will specify those properties without which an atom cannot continue to endure. Conversely, if atoms persist by being temporally extended, then the persistence conditions for an atom will identify the conditions of cross-temporal unity for an atom, i.e., the conditions under which successively existing atom-stages are stages of the same atom. Following David Lewis' use of 'endure' to denote threedimensional persistence, and 'perdure' to denote four-dimensional persistence, I shall sometimes speak of three-dimensional persistence conditions as endurance conditions, and of four-dimensional persistence conditions as perdurance conditions. 34 It is not hard to see that Locke's principium individuationis works equally well with both three- and four-dimensional objects. In the first place , both accounts are compatible with Locke's exclusion principle: we can say for three- and four-dimensional objects alike that no two objects of the same kind can exist in the same place at the same time . The same holds true for the single place principle: advocates of both three- and four-dimensionalism can agree that it is impossible for a single object to occupy two discontinuous regions of space at a single time. Similarly, they can also agree that there is a single, determinate time at which an object comes into existence. Hence on either of these views, one could hold that an object is individuated by the time and place at which it first came into existence, and indeed by every subsequent moment of its existence. And this fact, I contend, demonstrates that Locke 's principle of individuation is compatible with two very different accounts of what it is for a single object to exist at different times.

34

See Lewis (1986, 202).

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CHAPTER THREE 2. A metaphysical dilemma

I suspect that most of Locke's readers will be initially unimpressed by the above observation. For even if his principium individuationis is compatible with a four-dimensional account of objects, one might well take this to be irrelevant, on the eminently reasonable assumption that Locke (like everyone else of his day) advocated a three-dimensional view of objects. For the sake of argument, let us assume that they are right. If the objects in Locke's ontology persist by enduring through time in their entirety, then he is offering us endurance conditions for particular objects, conditions which specify the properties without which an object cannot continue to endure. Now these endurance conditions are either given relative to some particular sortal concept, or they are not. If they are not, then he is presumably specifying the conditions under which an object can continue to endure, period, and not merely relative to this or that sortal concept. Thus he is either specifying relative endurance conditions, or he is specifying absolute endurance conditions. If he is offering relative endurance conditions for particular objects, then he is specifying the conditions, for example, under which Tabby ceases to exist qua Cat, but not, say, qua Body. On the other hand, if he is offering absolute endurance conditions for particular objects, then he is specifying the conditions under which Tabby ceases to exist, simpliciter. I do not think that we should follow Udo Thiel (1983) and Edwin McCann (1987) in taking Locke to be offering relative endurance conditions for particular objects. For he cannot do this without committing himself to a relativized notion of identity. If he allows for cases in which an object a ceases to exist, qua G, but not qua F, then he will have to allow for cases in which a and b are the same F, but different G's. Since the relative identity thesis is incompatible with his principle of individuation, and his primary reason for writing this chapter was to elucidate this principle, it is unlikely he would have developed this theory in a manner which is obviously at odds with this principle. Thus if we take him to endorse a three-dimensional account of persistence, we should take him to be offering absolute endurance conditions for particular objects. Although he cannot posit relative endurance conditions without committing himself to the relative identity thesis-which is incompatible with his principle of individuation-he cannot posit absolute endurance conditions for particular objects without contradicting his anti-essentialism . For he cannot posit absolute endurance conditions for particular objects without attributing de re essential properties to them. Thus, for example, he cannot say that Tabby ceases to exist-absolutely, and not merely qua Cat--if she ceases to be alive, without saying that it is essential to Tabby,

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the res, that she be alive. Similarly, he cannot say that Socrates ceases to exist-absolutely, and not merely qua Person-if he ceases to be conscious, without saying that it is essential to Socrates, the res, that he be conscious. In other words, in positing absolute endurance conditions for particular objects, Locke is forced into the position which Quine refers to as Aristotelian essentialism. That is, he is forced into "adopting an invidious attitude towards certain ways of uniquely specifying x...and favoring other ways ...as somehow better revealing the 'essence' of the object" (1953, 155). Given the great amount of interest which has been directed both towards Locke's anti-essentialism and also towards his treatment of identity, and given that this chapter has almost universally been interpreted (explicitly or implicitly) along three-dimensionalist lines, it is surprising how infrequently this difficulty has been considered. Thus while Brody argues that Locke's theory of identity commits him to essentialism, he fails to point out the apparent tension which subsequently arises between this theory and his antiessentialism (1972, 331). Indeed as far as I can tell, no one does so for nearly another twenty years. But while Edwin McCann (1987, 66-67) and Kenneth Winkler (1991,224-26) both draw attention this problem, they also think it to be readily dissoluble. According to McCann, there is no real conflict between these theories because Locke is offering relative rather than absolute (three-dimensional) persistence conditions. Thus , once more, McCann writes that "we can take Locke to be saying that if we judge his identity as a man, he does not survive the loss of life, but judged as a body, for example, he does remain the same thing before and after death (at least for a time)" (1987, 67). But while I agree that this would solve the present problem, it would do so only at the expense of creating many others. For as I have already argued , Locke cannot offer relative endurance conditions without committing himself to a relativized notion of identity, and he cannot endorse such a notion without violating his principium individuationis, which he takes to be one of his fundamental principles of identity. McCann's solution, therefore, is unacceptable. For reasons which we have already considered, Winkler rejects McCann's proposed solution to the above problem . Following Vere Chappell (1989, 76-80), he denies that Locke takes there to be an object which can be characterized both as a man and as body. Nevertheless, Winkler thinks that the apparent tension between Locke's anti-essentialism and his theory of identity is "less dramatic than it seems" (1991, 224). On Winkler's account, Locke's anti-essentialism consists merely in the claim that "'F is essential to x' is proper and significant only if x has been placed beneath a sortal" (225). Now if this is all Locke's anti-essentialism amounts to, then surely Winkler is correct in thinking that there is no real problem

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here. For in his identity chapter Locke never gives persistence conditions for unsorted particulars. In other words, the persistence conditions which he offers for particular objects are always sortal relative. Thus, for example, the persistence conditions which he posits for Tabby would of course be relative to the sortal Cat, just as the persistence conditions which he posits for the Day Man are relative to the sortal Person. So if Winker's analysis of his anti-essentialism is correct, there is no real conflict between Locke's identity theory and his anti-essentialism. I contend that Winkler's dissolution of the above tension relies on an incomplete picture of Lockean anti-essentialism. In the first place, Locke's position on the sortal relativity of essential properties isn't primarily a semantic thesis. That is, he doesn't merely say that it is linguistically improper or insignificant to say that an unsorted particular is essentially F, he says that it is always false to say this sort of thing. In the second place, his anti-essentialism doesn't rest solely upon his thesis about the sortal relativity of essential properties, it also rests upon a thesis about the relativity of sortals themselves. That is, his antiessentialism also depends upon the contention that there is no single best way of sorting individuals into kinds or species. And it is precisely this thesis which conflicts with his theory of identity, if he endorses a three dimensional account of persistence. Locke simply cannot have it both ways. Given his contention that an object's persistence conditions are determined by the sortal concept under which it has been ranked, he cannot maintain both (i) that these are absolute persistence conditions, and (ii) that there are many, equally legitimate ways of ranking objects under sortal concepts. If, on the one hand, he truly takes these to be absolute persistence conditions, then he cannot accept the existence of other, equally legitimate ways of sorting this object, since each sortal concept will pick out a different set of persistence conditions. Rather, he will have to maintain that the sortal concept under which he ranked this object best reveals the essence of this object. Conversely, if he truly thinks that there are many, equally legitimate ways of sorting an object into kinds, he must accept the conclusion that there are many, equally legitimate sets of persistence conditions for this object, which requires that these persistence conditions be relative rather than absolute. Of the philosophers who have drawn attention to the apparent tension between his anti-essentialism and his theory of identity, only Ayers seems to recognize that this problem is not readily dissoluble. Thus Ayers : Many alleged contradictions in Locke 's thought melt away on closer examination, but in this case the charge sticks . In the first edition he was prepared to assume that an individual could in principle survive transmutation from horse into (say) sheep or swan, and indeed that I

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might continue to exist as an individual after the loss, not only of an 'accident' such as a characteristic colour, nor even of the shape which makes me human, but also of reason, memory, sense, understanding and life itself. Yet in the second edition, he carne also to propose that life constitutes the individual animal, while reason and memory, as 'consciousness' , constitute the self. (1991,2:206)

As Ayers points out, Locke's treatment of identity suggests that the property of being alive is essential to Tabby (and not merely to Tabby qua Cat) and similarly that the property of being conscious is an essential to Socrates (and not merely to Socrates qua person). For this reason, Locke' s treatment of identity seems to be flatly incompatible with his rejection of essentialism. In what remains of this work, however, I hope to show that Locke does avoid this contradiction. In Chapters Four and Five I argue that he is committed to a four-dimensional ontology, and in Chapter Six I argue that on such an ontology there is no obvious conflict between these theories.

4

LOCKE ON THE PERSISTENCE OF ORGANISMS AND PERSONS

In this chapter I argue that Locke 's account of persistence for both organisms and person s implies that these objects have both spatial and temporal extent, and hence both spatial and temporal parts. In Part One I discuss what he says about the persistence of organisms and their material parts, and I begin by arguing that his account of persistence for both atoms and masses is neutral with respect to the debate over temporal extent. I subsequently take up his treatment of persistence for organisms, and in particular, his contention that the organism a is the organism b if and only if a and b share in the same life. Although we have a pretty good idea of what a life is, on Locke 's view, I argue that it is not clear how lives succeed in playing the metaphysical role which he assigns to them . For there are at least two different ways in which an organism might be related to the event which is its life, one of which implies that organisms have both spatial and temporal extent , and other of which implies that they do not. In what remains of this section I argue that if we restrict our attention to his treatment of persistence for organisms , then we are not in a position to say which of these alternative reflects his considered view. In Part Two I discuss Locke ' s account of persistence for persons. Notoriou sly, this account proceeds exclusively in terms of sameness of consciousness: person b at tz is person a at t) if and only if (at t2) b is conscious of the thought s and actions which were had and performed by a at tl. After showing how this account stems from his concept of personhood, I develop his subsequent contention that the identity of the substances in virtue of which a and b are able to think "matters not". This leads, first, to a discussion of his agnosticism with respect to the ultimate nature of thinking substances, and second, to his criticism of the "Cartesian" account of personal identity, according to which person a is person b if and only if a and b share the same soul (thinking substance). In section two I discuss Locke ' s contention that consciousness might plays the same role in the case of persons as life plays in the case of organism s. I argue that his affirmation of this analogy, in conjunction with his account of the role which 101 C. H. Conn (ed.), Locke On Essence and Identity © Kluwer Academic Publishers 2004

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consciousness might play in the case of person, implies that the organism s in his ontology are partly composed of their constituent masses of matter, and hence that these organisms have both spatial and temporal extent. I subsequently argue that this position commits him to a four-dimensional account of persons . And finally in section three I further develop this interpretation through a discussion of various thought experiments and problem cases . L ORGANISMS AND THEIR MATERIAL PARTS

1. Atoms and masses

I contend that a four-dimensional account of objects enables us to make the best sense of a great deal of what Locke says about the persistence of organisms and persons . The same cannot be said about his treatment of identity through time for atoms, however. That is, neither of Locke's two statements about the persistence of atoms pushes us in the direction of fourdimensionalism, but neither, it seems to me, do they rule out such an account. In §2 of his chapter on identity he suggests that each particle of matter (= atom), like each finite spirit, has a determinate time and place of origin, and that "the relation to that time and place will always determine to each of them its Identity as long as it exists." Locke subsequently mentions a further condition which does not pertain to spirits , namely, that during an atom 's existence "no Addition or Subtraction of Matter" can be made. And in §3 Locke states that an atom, "i.e., a continued body under one immutable Superficies, existing in a determined time and place ...is the same, and so must continue, as long as its Existence continued: for so long it will be the same, and no other ." Following Bennett,' I contend that Locke's account of diachronic identity for atoms is conducted in terms of the integrity through time of a surface. His description of an atom as "a continued body under one immutable Superficies," suggests the following: the atom a (which occupies region rl at tl) is the atom b (which occupies r2 at t2) if and only if (i) the occupants of r l and rz exemplify the same set of spatial characteristics S, and (ii) the occupant of rl is spatio-temporally continuous with the occupant of ri in a way that constantly exemplifies S. I contend that this account is neutral with respect to the debate over temporal extent, since it can be satisfied by both sorts of persisting bodies , i.e., by bodies which persist by enduring, and by bodies which persist by being temporally extended. In the first place, I

See above, p. 67.

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Locke's account is satisfied if 'a ' and 'b' refer to an enduring atom which entirely occupies these regions, provided that this atom exemplifies S at every moment in time from t) to t2. In the second place, this account is also satisfied if 'a ' and 'b' refer to a temporally extended atom which partly' occupies these regions, provided that this atom's stages from t) to tz all exemplify S. Since a mass of atoms is "only the Cohesion of Particles any how united" (§4), I contend that atoms have temporal extent if and only if masses have temporal extent. For in the first place, if each of its members exists at every moment of its existence, then surely the whole mass exists at every moment of its existence. Similarly, if atoms are temporally extended objects, then the masses of these atoms will also be temporally extended. In other words, if atoms are the four-dimensional sums of their temporal parts, then so are masses of atoms. Indeed, each of a mass's temporal parts would be a (synchronic) concretion of spatially extended atom-stages. For the moment, the question of whether Locke attributes (or is committed to attributing) temporal extent to atoms and masses should remain an open one. For as I have argued, his treatment of persistence for both atoms and masses neither precludes nor implies a four-dimensional account of such objects. Once I show that he is committed to a fourdimensional account for organisms and persons, I shall argue that he is committed to extending this account to atoms and masses. 2. Organisms, Masses, and Lives

As we saw in the previous chapter, Locke acknowledges the existence of both organisms and masses of matter, and he thinks that masses have their parts essentially, while organisms do not. This difference is grounded in his accounts of what organisms and masses of matter are, in conjunction with his insistence that identity be "suited to the idea". A mass of matter, on his view, is not merely a "cohesion of bodies any how united," it is the cohesion of a particular collection of atoms, one, moreover, which has its constituent members essentially. Suppose, once more, that a mass of matter m is composed of atoms aJ, a2, and a3' On Locke's view, m will continue to exist only as long as precisely these atoms remain in some manner of mutual contact. Should al be separated from this collection, or should these atoms be joined by another atom a4, then m would cease to exist, and a new mass will have come into being.

2 I shall speak of a temporally extended obj ect 0 as partly occupying a region of space if and only if at least one of O's proper parts completely fills this region of space.

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While Locke refers to both masses and organisms as bodies, organi sms are not merely bodies, but "living organized bodies" (§8). As living bodies, they exhibit such physiological processes as respiration and digestion, processes which involve the organism's casting off some atoms as parts and taking in others. Since a body can exhibit these processes only if its parts are arranged in a highly complex manner, one which is "fit to receive , and distribute nourishment" (§4), it follows that living bodies are highly organized. Thus , the feature which is essential to the continued existence of masses (namely, sameness of constituent parts) is incompatible with the continued existence of organisms, while the feature which he takes to be is irrelevant to the continued existence of masses (namely, arrangement of parts) is essential to the continued existence of organisms. Since organisms are composed of different atoms at different times, the question of whether the organism a at t, is the organism b at tz is not a function of the atoms which constitute a and b. Thus he writes in §3 that "in the state of living creatures, their identity depends not on a mass of the same particles; but on something else." In §§4-8 his account of what this "something else" involves becomes clear: a and b are the same organism if and only if a and b participate in the same life. In §4 he writes : That being then one Plant, which has such an Organization of Parts in one coherent Body, partaking of one Common Life, it continue s to be same Plant, as long as it partakes of the same Life, though that Life be communicated to new Particles of Matter vitally united to the living Plant, in a like continued organization , conformable to that sort of Plants.

Now a life, on Locke's view, is a particular biological event which extends through time from the first moment an organism's existence to its last. This comes out pretty clearly in what remains of §4: For this Organization being at anyone instant in anyone Collection of Matter, is in that particular concrete distinguished from all other, and is that individual Life which existing constantly from that moment both forwards and backwards in the same continuity of insensibly succeeding Parts united to the living Body of the Plant, it has that Identity, which makes the same Plant, and all the parts of it, parts of the same plant, during all the time that they exist united in that continued Organization, which is fit to convey that Common Life to all the Parts so united.

Thus Locke explains the persistence of organisms in terms of the persistence of lives . This account depends upon two implicit assumptions. First, since he says almost nothing about the persistence of lives, even though he explains the persistence of organisms in terms of them, he is evidently

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assuming that we are capable of determining both (i) when we are dealing with a single life at different times, and (ii) when we are dealing with different lives at a single time. In other words, he is assuming that lives are well individuated events. In connection with this assumption Peter van Inwagen writes: A life is a reasonably well-individuated event. There is often a reasonably clear answer to the question whether a life that is observed at one time .. .is the same life as a life that is observed at another time... . This is because a life is a self-directing event. If a life is at present constituted by the activities of the xs [i.e., the material simples which are presently involved in these activities], and was ten years ago constituted by the activities of the ys [the material simples which were then involved in these activities], then it seems natural to identify the two events if there is a continuous path in space-time from the earlier to the present space-time location, along which the life of ten years ago has propagated itself. It is this feature of lives, their seeming to be well individuated, that made it possible for Locke to explain the identity of a man in terms of the identity of a life and thereby to offer something that we can at least take seriously as a possible explanation of human identity. If lives did not at least appear to be well-individuated events, Locke's explanation would not even be worth considering; we should all regard it as an explanation of the obscure through the no less obscure. (1990,87)

Second, since Locke thinks that each organism is itself individuated by a particular life, he is also assuming that lives are what van Inwagen refers to as jealous events, i.e., that there is exactly one life for each organism, which is itself unique to this organism," Now it is not entirely clear how lives succeed in playing the metaphysical role which Locke assigns to them. In particular, it is not clear what the connection is between the persistence of Tabby (which is presumably a biological substance) and the persistence of her life (which is clearly a highly complicated, temporally extended, biological event). In what remains of Part One I shall argue, first, that an organism and its life must be related in one of two fundamentally different ways; and second, that if our attention is restricted solely to his treatment of persistence for organisms, then we do not have adequate grounds for selecting one of these as his "official" account. Since persisting organisms are composed of different collections of atoms at successive instants of time, and each of these collections of atoms is itself a distinct mass of matter, for each persisting organism there will be a In the pages which follow the above passage, van Inwagen gives a convincing account of why lives must be thought of as jealous events.

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corresponding series of numerically distinct, successively existing masses of matter. Suppo se, for example, that Tabby exists from tl to tn, and that during this time she is composed of individual masses of matter (m ), m 2, m 3,...m n), so that she is composed of ml at t ), of m 2 at t2, and so on. We must now addre ss the following question: how, precisely, is Tabby related to these masses? And how, for that matter, are these masse s related to one another? There are evidently only two ways of answering the first question: she is either wholly composed of each of these masses, in succession, or else she is wholly composed of the whole series of masses, and hence partly composed of each mass at these respective times. At least for our purposes, this question is a momentou s one. For in settling this issue, at least for Locke, we will also have settled the question of whether the organisms in his ontology have both spatial and temporal extent, which will, in tum, help to shed some light on the relation ship between an organism and the event which is its life. How is the question about how Tabby is related to these successive masses related to the question of whether she has temporal extent? As a persisting organism, Tabby either has temporal extent, or she lacks temporal extent. If she is only partly composed of each of her constituent masses, so that she is wholly composed of the whole series, then she has temporal extent. Conversely, if she is wholly composed of each of her constituent masses, in succession, then she lacks temporal extent. For if an organism is wholly composed of these masses, in succession, then it would be possible for an organism to exist, in its entirety , at a single moment of its existence. Since this is not possible for a perduring object, if an organism is wholly composed of each of its constituent masses, then organisms persist by enduring. Conversely, if an organism is only partly composed of its constituent masses, so that it is wholly composed of the whole series, then it couldn 't possibly exist, in its entirety, at a single moment of time. And since this is not possible for an enduring object, if organisms are only partly composed of their constituent masses, then organisms persist by perduring. In his identity chapter Locke is attempting to specify the persistence conditions for atoms, masses, organisms (first plants, then animals), and persons. As we have seen, he explains the persistence of organisms in terms of the persistence of lives, although as he presents this account, is not entirely clear how an organism is related to its life, or how lives are able to play the metaphysical role which he assigns to them. I think that getting clearer on the temporal extent of the organism s in Locke's ontology will help to shed some light on these matters. Thus, for example, if the organisms in his ontology persist by being temporally extended, then the persistence conditions for an organism such as Tabby would specify the conditions of cross-temporal unity for a cat, i.e., the conditions under which

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successively existing masses of matter will all be parts of the same temporally extended cat. To put this in more Lewisian terms, on this view an organism would be a maximally life-related aggregate of shorter-lived organism-stages, each of which would be a suitably arranged mass of matter. And this helps to explain how lives can play the metaphysical role which he assigns to them, since on this view an organism's life would consist in supervene upon the causal relationship between these successively existing masses, i.e., the causal relationship which brings it about that these masses are parts of the same temporally extended thing. Although a four-dimensional account of objects seems to shed some light on the metaphysical role of lives, it does so at the expense of making it difficult to distinguish between an object and its life. Since an organism and the event which is its life would have exactly the same spatial and temporal boundaries, it is hard to resist the conclusion that we are really dealing with a single thing, which might be characterized either as an event-like substance or a substance-like event. For obvious reasons, this problem does not arise if the organisms in Locke' s ontology persist by enduring through time in their entirety. But it is not as if a three-dimensional ontology is without its problems, at least for Locke. Consider the region of space r which Tabby occupies at til while she is wholly composed of the mass of matter mi . Since Locke recognizes the existence of both organisms and masses of matter, on this ontology he is committed to saying that two objects wholly occupy r at this time. Now we might have thought that we could touch a cat without touching something else which, though not a cat, is very like a cat. But on this view, we cannot. For we cannot touch a cat without also touching a mass of matter which is hence not a cat, but which has exactly the same intrinsic properties as the cat has at this time. Since these objects will have exactly the same parts which are obviously arranged in exactly the same way, these objects will have exactly the same size, weight, outward texture, and so on. It is thus no wonder that so many philosophers would take this implication to amount to a reductio of his position. Does Locke think that an organism is wholly composed of its constituent masses, or does he instead think that it is partly composed of them? Does he think that an organism's life plays the sort of role which van Inwagen would assign to it, or is his position closer to Lewis's? Do the organisms in his ontology persist by enduring, or by perduring? If I have argued correctly, then an answer to any of these questions would provide answers to the rest. And lest anyone should think that a four-dimensional Lockean ontology is simply out of the question, I would like to point out that a number of his commentators have attributed positions to him which come close to

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committing him to such an ontology, while still others have clearly (though perhaps unwittingly) left him with such a commitment. Martha Bolton, for example , comes close to attributing both spatial and temporal extent to Lockean organisms when she refers to them as 'seriesbeings'. According to Bolton, Locke takes an oak to be "a series of different masses of matter...which exists at times when each of the successive masses has been destroyed or has not yet been formed by the flux of particles" (1994, 115). On her interpretation, particular objects (of all types) continue to exist as long as something continues to exist which exemplifies this type. Thus, for example, she writes that "an oak, identified at a place and time, persi sts as long as something is continuous with it and what continues is in the species oak" (113). Although she speaks of oaks as persisting, it is not clear how an oak is related to its corresponding series of masses. In referring to an organism as a "series-being," I am inclined to think that she takes them to have temporal extent. But there is no suggestion that an oak is composed of these successively existing masses in the way that this position requires. Edwin McCann comes closer to suggesting that Lockean organisms are diachronically compounded out of its these successively existing masses, since he explicitly states that these successive masse s are united by a life. In the end, however, it is not clear whether these organism s are real, persisting entitie s, which obviously raises doubts about whether they persist by being temporally extended. For on McCann's interpretation, the life which unites successive masses into a single thing is a kind of artifact-an artifact, he writes, which is "grounded in long and careful observation (natural history) and so too, probably, in the underlying facts about the structures of things...but for all that, an artifact, due primarily to the abstract ideas we construct" (1987, 67). Thus according to McCann , "as long as [a] succession of parcels of matter continues to satisfy our idea of an oak-tree there will be the same continued life and so the same oak-tree" (67). Now if lives are artifacts, as McCann suggests, then I take it that they don't really succeed in uniting successively existing masses into single, temporally extended organism. In other words, it looks as if the persisting organisms in such an ontology would be just as artificial as the lives which give rise to them. So I suspect that McCann would stop short in saying that Locke's organisms are temporally extended entities. The most he could say, it seems to me, is that they are useful fictions which are ultimately grounded in objective biological processes and events. Let us now turn to some commentators who do-even if unwittinglycommit Locke to a four-dimensional account of organisms. Mackie , for example , freely commits Locke to the existence of temporal parts, in the form of 'thing-occurrences' , 'thing-phases', or 'thing-slices' . Thus, for

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example, Mackie states that "Locke's general theory of identity through time is that x-occurrences at t) and at t2 are occurrences of the same x if and only if there is a continuous x-history linking them" (1976, 142). Now since Mackie thinks that the expressions 'thing-occurrence' , 'thing-phase' and 'thing-slice' are equivalent," he cannot merely be attributing temporal parts to a thing's history : he must also be attributing temporal parts to the things themselves. But Mackie does not suppose that Locke attributes temporal extent to the aggregates of these parts. Instead, he assumes that Locke shares "our" conception of a persistence, according to which a persisting object is something "that is all there at once, at any time when it exists at all" (1976, 140-50). Alston and Bennett also suggest that Locke takes an oak to be compounded out of successively existing masses of matter. Thus they write that "our idea of an oak doesn't just guide us in marking off oaks from elms, etc.; it also guides us in marking off the masses-at-times that do from those that do not temporarily constitute a single oak" (1988, 44). In a footnote to this passage they explain that their use of use of 'masses-at-times' is s facon de parler: We do not populate Locke's ontology with any such items as "masses-at-times." Everything we say about which masses-at-times constitute an oak can be correctly though long-windedly expressed as a statement about which masses are temporarily parts of the oak, with the understanding that each mass is identified in terms of where it is and how it is organized at a particular time. (44)

From the footnote on the following page it is clear that their worry about committing Locke to "masses-at-times" can be equivalently phrased in terms of committing him to mass-stages, for they suggest that 'persons-attimes' is equivalent to 'person-stage' (45).5 And while they may have not committed Locke to mass-stages, they apparently have committed him to the view that oaks have temporal stages, and hence that a single oak is the temporally extended sum of its stages. For as I have already argued, there is no other way for successively existing masses to be "temporarily parts" of a single oak. William Uzgalis also seems to commit Locke to a four-dimensional view of organisms, for like the above writers he thinks that Locke takes an organism to be diachronically compounded out of successively existing masses of matter (1990, 289). Indeed, at one point he suggests that an oak is composed by a "temporal sequence" of such masses, and that it is the meaning of the sortal 'oak ' which determines the "unity conditions" for such 4 5

See (1976 , 144). See also Bennett (1971, 337) .

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a thing (288). From the context it is clear that Uzgalis is speaking of diachronic unity conditions, for these unity condition s are supposed to determine the temporal boundaries of particular oaks, i.e., they are to determine which temporal sequences of masses compose a single oak. Kenneth Winkler comes perhaps the closest to explicitly attributing a four-dimensional view of organisms to Locke. For he suggests that we can profitably think of Lockean organi sms as bein g composed of a series of temporal parts or substance-stage s which are held together by a certain unity relation. But while he finds this to be a 'Lockean ' suggestion," he refrains from attributing it to him, "if only because there is no hint in the Essay that substance-stages can (or should) be treated as building block s" (1991, 216). Vere Chappell has pro vided the most prolonged treatment of the relationship between an organism and its constituent masses of matter. After defending the contention that Locke take s masses and organisms to be compound substances, he points out that we need to keep two factors in mind when con sidering nature of such substances. First, we need to isolate the components of a particular compound, and second, we need to determine the mann er in which these components are united to form a single object (1990, 23). According to Chappell, Locke take s organisms to be composed both of atom s, and of masses of atoms, but in very different ways. Thu s he argues that "corresponding to these two sorts of constituents are...two sorts of compounding" (24). He refers to the sort of compounding which pertains to atoms as synchronic compounding. In an instance of this sort of compounding, he writes, "simultaneously-existing atoms combine to make up an organi sm at any one time. To do this, such atom s must be joined together so as to constitute a living body; they must be so organized as to be 'fit to receive , and distribute nouri shment,' and in general 'partake of one Common Life " (330-3 1). Con versely, he refers to the sort of compounding which pertains to masses as diachronic compounding. In an instance of diachronic compounding, he explains, "masses of matter existing in temporal succession combine to make up an organism persisting through time...In this case , the succe ssive masses must be joined in such wise that the life inherent in one of them can be passed on or 'communicated' to its successor" (24f) . Thu s on Chappell' s account, Lockean organi sms are doubly compound substances, i.e., they are synchronically composed of atom s, and diachronically composed of masses of atom s. Clearly there is no contesting the fact that Locke takes organisms to be composed of atoms. But why doe s It is Lockean, he suggests, "in its willingness to question the assumption that the notions of an enduring corpuscle, compound body, or simple immaterial substance are less problematic-more perspicuous, or known to be more firmly grounded in what there is-than the notion of a person" (199 I, 2 16t).

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he also take Lockean organisms to be diachronically composed of masses? Because he takes Locke to specify two conditions which must be met if a pair of successive masses are to belong to a single, persisting organism. First, these masses must be temporally continuous with one another. For otherwise the life which is 'inherent' in the first will fail to be passed on to the second. Second, he requires that the body of a persisting organisms be "not shifted all at once" (§8), i.e., he requires that most of the atoms which (synchronically) compose the first mass must also compose the second (25). Although Chappell takes Lockean organisms to be diachronically compounded out successively existing masses of matter, he does not draw attention to the fact that such organisms must have both spatial and temporal extent. Indeed, he seems to think that these organisms would not have temporal extent, since he thinks that Locke is committed the thesis that at any given moment, an organism and its constituent mass of matter occupy the same region of space (1990, 22-3).7 In particular, he seems to think that Locke is committed to this thesis in a way that many philosophers have found objectionable, which is to say that he is committed to the view that both objects wholly occupy the same region of space at the same time. And while this assuredly is a consequence of the three-dimensional version of Locke's ontology, it is just as assuredly not a consequence of the fourdimensional alternative. For on the latter view, the whole object and the whole organism do not occupy the same region of space at the same time; rather, the relationship between the organism and this mass is that of a whole and one of its proper parts. Thus Locke is committed to coincident entities only if he thinks that an organism is wholly composed of its constituent masses, in succession. But on that view it would surely be wrong to think of organisms as diachronically compounded out of these masses, since these masses wouldn't be parts ofthis organism." Although I will eventually concur with Chappell's contention that Lockean organisms are diachronic compounds, I do not think that the passages he cites constitute sufficient textual evidence for this reading. For the two conditions which he attributes to Locke-the conditions under which two successively existing masses can belong to the same organismcould also be affirmed by someone who thinks that an organisms is wholly composed of these masses, in succession. More generally, if we restrict our attention to the discussions of organisms which precede his treatment of See also Chappell (1989,75). There is a sense in which each of these masses would be parts of this organism (which Locke would not have recognized): each mass would have been an improper part of it. But the point is that on the three-dimensional ontology, these successive masses wouldn't have together been parts of it, which is what the notion of diachronic compounding seems to require.

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personal identity (§§3-8), we will not find adequate grounds for choosing between the three- and four-dimensional readings which I have developed above. Consider the following passage from §4: For this Organization being at anyone instant in anyone Collection of Matter, is in that particular concrete distinguished from all other, and is that individual Life, which existing constantly from that moment both forwards and backwards in the same continuity of insensibly succeeding Parts united to the living Body of the Plant, it has that Identity, which makes the same Plant, and all the parts of it, parts of the same Plant, during all the time that they exist united in that one continued Organization, which is fit to convey that Common Life to all the Parts so united. (331:9-18)

I think that this passage has the best chance of supporting the contention that a Lockean organism is built up out of a series of distinct, successively existing bodies or 'collections of matter', and that these bodies are united into a single, persisting object in virtue of their partaking of a common life. For he might seem to be suggesting that the shared, organizational features of these successively existing collections of matter enable them to be parts of a single, persisting organism. Although I had previously advanced just such an interpretation," I am now convinced that it is unwarranted. For it is simply not clear that he is using 'parts' to refer to these successively existing masses of matter. Moreover, the first instance of 'part'-in the phrase "in the same continuity of insensibly succeeding Parts united to the living Body of the Plant"-is evidently not a reference to masses, but rather to atoms. For surely it is atoms which are being united and separated to the living (and hence persisting) body of a plant in an imperceptibly rapid manner. In the other relevant passages in §§5-8 we find a similar emphasis on atoms , and even less emphasis on these successively existing masses . In §5, for example, in discussing what artifacts would have to be like in order for them to persist in the same manner as animals, he writes the following: If we would suppose this Machine one continued Body, all whose organized Parts were repair'd, increas'd, or dirninish'd by a constant Addition or Separation of insensible Parts, with one Common Life, we should have some thing very much like the Body of an Animal, with this difference, That in an Animal the fitness of the Organization, and the Motion wherein Life consists, begin together, the Motion coming from within; but in Machines the force, coming sensibly from without, is often away, when the Organ is in order, and well fitted to receive it.

9

See Conn (1999,432).

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In §6 he immediately continues with the following statement regarding the persistence of animals: This also shews wherein the Identity of the same Man consists: viz. in nothing but a participation of the same continued Life, by constantly fleeting Particles of Matter, in succession vitally united to the same organized Body.

In the context of defending this point he gives yet another statement regarding the persistence of animals, to wit, that man' s ability to persist consists in its being "like that of other Animals in one fitly organized Body, taken in anyone instant, and from thence continued under one organization of life in several successively fleeting Particles of Matter united to it." And finally, at the start of §8, he states his position on animals one last time: An Animal is a living organized Body; and consequently the same Animal, as we have observed, is the same continued Life communicated to different Particles of Matter, as they happen successively to be united to that organiz'd living Body.

In each of these passages, we find a reference to a living (and hence persisting) "organized body" which is taking in new atomic parts in an exceedingly rapid manner. Although he is certainly committed to the thesis that each momentary collection of atoms composes a distinct, successively existing mass of matter, he doesn't mention their existence , much less take up the question of how an organism is related to them. I conclude, therefore, that Locke's explicit discussion of the persistence of plants and animals do not provide us with adequate grounds for choosing between the three- and four-dimensional accounts which I have developed above. As far as I can tell, his statements about the persistence of organisms are compatible with both of these accounts, since his emphasis is almost exclusively on the atomic parts of these organisms, and neither account takes issue with this. More to the point, since he does not clearly address the relationship between an organism and its constituent masses, on the basis of these passages we have no basis for deciding whether he takes a persisting organism to be wholly or partly composed of these successive masses. II. LOCKE'S ORGANISMIC THEORY OF PERSONAL IDENTITY

1. Persons, consciousness, and the nature of thinking substances

As we have just seen, Locke's account of identity for organisms is primarily a function of his account of what an organism is, an account,

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moreover, which centers on the fact that an organism is a living thing. Thus on his view, the organism a at tt is the organism b at ti if and only if a and b share in the same life, where a life is a prolonged and reasonably well individuated biological event. Locke's account of sameness for persons follows a very similar pattern. As we saw in the last chapter, his discussion of personal identity begins in the following manner: This being premised 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 it self as it self, 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 be essential to it: It being impossible for anyone to perceive, without perceiving, that he does perceive. [§9]

As with organisms, his account of sameness for persons is a function of his account of what a person is, an account which centers on the fact that persons are conscious, sentient beings. Thus later in the same section he presents the following account of personal identity: For since consciousness always accompanies thinking, and 'tis that, that makes everyone to be, what he calls self; himself from all other thinking things, in this alone consists personal Identity, i.e., the sameness of a rational Being: And as far as this consciousness can be extended backwards to any past Action or Thought, so far reaches the Identity of that Person. [§9]

On this view, the person a at tl is the person b at tz if and only if b is (at t2) conscious of the thoughts and actions which were had and performed by a at ti - In other words, a is b if and only if a and b share in the same "stream of consciousness," which he takes to be a prolonged-though perhaps intermittent--directly accessible mental event." Though his theory of personal identity centers on the fact that persons are conscious beings, there are other features of his notion of personhood which play an important role in his treatment of personal identity. In the first place, in addition to being self-conscious beings, on his view persons are also morally responsible beings. And this illustrates the most important difference between his notion of what it is to be a person, and what it is to be a man. For Locke, "man" is a biological concept, since a man is merely an animal of a particular size and shape. This comes out most clearly in the following passage from §8:

10 For Locke's suggestion that persons may persist in a "gappy" or intermittent manner, see § 16 (340: 30-33) and § 17 (341: 24-28). I will return to this issue later in the chapter.

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An animal is a living organized Body; and consequently, the same Animal, as we have observed, is the same continued Life communicated to different particles of Matter , as they happen successively to be united to that organiz'd living Body. And whatever is talked of other definitions, ingenuous observation puts it past doubt, that the Idea in our Minds, of which the Sound Man in our Mouths is a sign, is nothing else but of an Animal of such a certain form .

Whereas he takes "man" to be a biological concept, he takes "person" to be aforensic concept, i.e., one which is inextricably tied to the notions of moral responsibility, desert, and judgment. Not surprisingly, these themes have an important place in his treatment of personal identity. Witness the first and last sentences from § 17, together with the first sentence from § 18: Selfis that conscious thinking thing, (whatever Substance, made up of whether Spiritual, or material, Simple, or Compounded, it matters not) which is sensible, or conscious of Pleasure and Pain, capable of Happiness or Misery, and so is concem'd for it self, as far as that consciousness extends ...That which the consciousness of this present thinking can join it self, makes the same Person, and is one self with it, and with nothing else; and so attributes to it self, and owns all the Actions of that thing, as its own , as far that consciousness extends , and no father ; as everyone who reflects will perceive. [§ 17] In this personal Identity is founded all the Right and Justice of Reward and Punishment; Happiness and Misery, being that, for which everyone is concerned for himself, not mattering which becomes of any Substance, not joined to, or affected with that consciousness. [§ 18]

On Locke's view, one is morally responsible for an action-and hence worthy of praise or blame, reward or punishment-if and only if one is conscious of having performed this action. He reiterates this contention in §26: Person, as I take it, is the name for this self. Where-ever a man finds, what he calls himself, there I think another may say is the same Person. It is a Forensick Terms appropriating Actions and their Merit; and so belongs only to intelligent Agents capable of a Law, and Happiness and misery . This personality extend it self beyond present Existence to what it past, only by consciousness, whereby it becomes concerned and accountable, owns and imputes to it self past Actions , just upon the same ground, and for the same reason, that it does the present.

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Later in §26 Locke develops the connection between happiness, consciousness, and adjudication in the following manner: All which is founded in a concern for Happiness the unavoidable concomitant of consciousness, that which is conscious of Pleasure and Pain, desiring, that that self, that is conscious, should be happy. And therefore whatever past Actions it cannot reconcile or appropriate to that present self by consciousness, it can be no more concerned in, than if they had never been done: And to receive Pleasure or Pain; i.e., Reward or Punishment, on the account of any such Action, is all one, as to be made happy or miserable in its first being, without any demerit at all.

Here Locke maintains that one's "concern for Happiness" is the "unavoidable concomitant of consciousness." Why? Because one cannot experience both happiness and misery without also desiring to be happy rather than miserable. Surely this is a reasonable claim: for any mental state (type) X, if one desires to remain in this state, then X is not pain or misery; and if one desires to be free from this state, then X is not pleasure or happiness. The connection between happiness, misery and judgment is also straightforward. To be rewarded (or punished) for a past action is nothing more than to be made happy (or miserable) on account this action. In what remains of §26 he affirms this position as part of a traditional Christian account of divine judgment and the afterlife. He thus goes on to contend that at the Last Judgment we will be rewarded or punished only for those actions which we are conscious of having performed : The Apostle tells us, that at the Great Day, when everyone shall receive according to his doings, the secrets of all Hearts shall be laid open. The Sentence shall be justified by the conscious all Persons shall have, that they themselves in what Bodies soever they appear, or what Substances soever that consciousness adheres to, are the same, that committed those Actions, and deserve that Punishment for them.'!

Locke's contention in § 17, that "self is that conscious thinking thing, (whatever Substance, made up of whether Spiritual, or material, Simple, or Compounded, it matters not)" reveals another important aspect of his concept of personhood : though persons are essentially conscious substances, this concept is intentionally neutral with respect to the ultimate 11 In a marginal note Locke appeals to 1 Cor. 14:25 ("After the secrets of the unbeliever' s heart are disclosed, that person will bow down before God and worship him, declaring, 'God is really among you." ,) and 2 Cor. 5:10 ("For all of us must appear before the judgment seat of Christ, so that each may receive recompense for what has been done in the body, whether good or evil").

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metaph ysical nature of conscious, thinking substances. This feature of his concept of personhood is surely a function of his deep-seated agnosticism on this matter. Since this agnosticism has important implications for his theory of personal identity , I would like to say a bit more about his philosophy of mind, particularly as it relates to Descartes and Hobbes. In the Second Meditation Descartes contends that we can fully understand what it is for something to be a thinking thing without any regard to whether it is also an extended thing, and in the wax passage he defend s the converse of this claim. These contentions commit Descartes to what is sometimes called property dualism, a view which states (i) that each of an object' s simple properties is either a mental property or a corporeal property (but not both), (ii) that each of an object's non-simple properties (e.g., the property of being both F and G, or the property of being not-G or not-H) is, into simple properties.V and (iii) that no simple property of either sort is explanatorily reducible or conceptually connected to simple properties of the other sort. Given his commitment to property dualism, it follows for Descartes that minds are distinct from bodies in one of two ways: there is either a modal distinction between minds and bodies, in which case thought and extension are distinct and conceptually irreducible modes of a single substance, or else there is a real distinction between minds and bodies, in which case thought and extension are alway s attribute s of distinct substances which belong to fundamentally different kinds." While both of these possibilitie s depend upon the truth of property dualism, the second also depends upon substance dualism, the thesis that no one substance has both mental and corporeal properties. Descartes is careful to point out that he is not in a position to affirm substance dualism from the vantage point of the Second Meditation. Thus , for example, he asks whether it might be the case "that these very things which I am supposing to be nothing [namely, bodies], because they are unknown to me, are in reality identical with the 'I' of which I am aware" (CSM II:18; AT VII:27).14 In the Sixth Meditation, however, he offers two separate arguments for substance dualism, arguments which purport to show that there cannot merely be a modal distinction between minds and bodies. First, he argues that there must be a real distinction between minds and bodies, "since they are capable of being separated, at least by God." In For details on how such a resolution might proceed, see Bennett (1984, 43). Descartes defines these distinction in the Principles 1.60-62 (CSM 1:213-15; AT VllIA :2831). 14 He reiterates this point in the second (CSM 11:93; AT VII:129), fourth (CSM II:155f; AT VII:220f), fifth (CSM 1I:247f; AT VII:247), and seventh (CSM 11:333; AT VII:492) sets of replies. 12

13

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short, Descartes argues that minds and bodies must be numerically distinct substances, since their separate existence is conceivable, and hence possible .15 His second argument for substance dualism is based upon his observation that bodies are essentially divisible, while mind are essentially indivisible. We know why he takes bodies to be essentially divisible: he thinks that bodies are essentially extended things, and that nothing is both extended and indivisible. Why does he think that minds are essentially indivisible? In the Synopsis of the Meditations he takes this to follow from the fact that "we cannot conceive of half a mind, while we can always conceive of half a body, however small". In the Sixth Meditation he takes this to follow from the fact that we are unable to distinguish any parts within our minds. Thus in the first case this conclusion is grounded in the incoherence of a concept, while in second case it is grounded in direct, introspective awareness. While it is pretty clear that Locke advocates property dualism, he does not endorse Descartes' substance dualism, for he is unwilling to conclude "that Omnipotency it self, cannot give Perception and Thought to a Substance, which has the Modification of Solidity" (IV.iii.6: 542). Although he refrains from endorsing a dualistic account of mentality, neither does he endorse a materialist account. For in addition to rejecting the Cartesian view that thinking substances must be immaterial, he also rejects the Hobbesian view that thinking substances cannot be immaterial. While he suggests that either of these conclusions might be true, he finds both to be unwarranted : 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 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, still drive him to the contrary side. (IV.iii.6: 542)

Accordingly, he reproaches those who claim to have proved either of these suppositions with being "over zealous". For, he writes, "it becomes the Modesty of Philosophy , not to pronounce Magisterially, where we cant that 15 Versions of this argument occur in the Sixth Meditation (CSM 11:54; AI VII:78), in the second set of replies (CSM II:119f; AT VII:169f), and in the Principles I.60 (CSM 1:213; AT VIIIA:28f).

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Evidence that can produce Knowledge." Thus while he acknowledges the possibility of thinking matter, he repeatedly insists that we will never know whether our mental capacities are ultimately grounded in immaterial spirits or in fitly disposed systems of matter. Towards the end of this same section, for example, he writes that "'tis past controversy, that we have in us something that thinks, our very Doubts about what it is, confirm the certainty of its being, though we must content ourselves in the Ignorance of what kind of Being it is" (IV.iiL6: 543). In §21 Locke takes up this same issue in connection with human beings. "We must consider," he writes "what is meant by Socrates, or the same individual Man." He subsequently lists the following possibilities : First, It must be either the same individual, immaterial, thinking Substance : In short, the same numerical Soul, and nothing else. Secondly, Or the same Animal, without any regard to an immaterial Soul. Thirdly, Or the same immaterial Spirit united to the same Animal.

In short, he states that we must think of Socrates, the man, as being either (i)

an immaterial, thinking substance, (ii) a thinking animal (which mayor may not be endowed with an immaterial soul), or (iii) a soul/animal composite, i.e., an "immaterial spirit which is united to the same Animal". He goes on to argue that on any of these accounts, we must stilI conceive of personal identity in terms of continuity of consciousness . Leaving these arguments aside, I would like to focus upon Locke's own position in this regard. In §8 he states that a man is "nothing else but of an animal of such a certain form," with an animal being defined earlier in this section as a "living, organized body". I conclude, therefore, that he accepts the second of these three positions. And while he tolerates the third position, he must categorically reject the first. While the three positions listed above are given in connection with the metaphysical nature of human beings (that is, organisms of certain size and shape), we can ask the same question concerning human persons (that is, self-conscious, rational beings which happen to have living human bodies). Although Locke is agnostic about the ultimate nature of thinking substances, and though he wants his account of personal identity to hold no matter what their nature turns out to be, he must reject the supposition that we are immaterial thinking substances which merely happen to associated with a body. For in §§ll, 17, and 25 he argues that (human) persons have material parts, which obviously precludes them from being purely immaterial, thinking substances. In § I I, for example, he writes:

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CHAPTER FOUR That this is so, we have some kind of Evidence in our very Bodies, all whose Particles, whilst vitally united to this same thinking conscious self, so that we feel when they are touch'd, and are affected by, and conscious of good or harm that happens to them, are part of our selves: i.e., our thinking, conscious self. Thus the Limbs of his Body is to everyone a part of himself He sympathizes and is concerned for them. Cut off an hand, and thereby separate it from that consciousness, we had of its Heat, Cold, and other Affections, and it is then no longer a part of that which is himself, any more than the remotest part of Matter.

Here Locke contends that as persons we are not merely associated with bodies, we have bodies, in the sense that we have bodily parts. That is, each person has, as constituent parts, those members of which he is conscious. This passage indicates that he does not equate consciousness with memory, as is frequently suggested . For it is certainly not memory that extends to one's material parts, but rather one's present, bodily sensations. He would thus not agree with Reid's contention that the supposition of a "part of a person is a manifest absurdity" and hence that "a person is something indivisible, and is what Leibnitz calls monad. ,,16 In the remainder of § 11 he takes the fact that persons have bodily parts to have the following implication: Thus we see that the Substance, whereof personal self consisted at one time, may be varied at another, without the change of personal Identity: There being no Question about the same Person, though the Limbs, which but now were a part of it, be cut off.

Locke's point here is that like organisms and unlike masses of matter, a person is capable of gaining and losing material parts without ceasing to exist. As with organisms, personal identity does not depend upon sameness of material parts, but upon something else. As we shall see in the section to follow, Locke also affirms a much more radical version of this principle, to wit, that personal identity neither depends upon sameness of constituent (immaterial) thinking substances. We have already encountered Locke's position with respect to the second of the three suppositions mentioned in §2I, i.e., the supposition that we are purely material self-conscious organisms. He thinks that this supposition might be true, but that it is not demonstrably true. In short, he thinks that it is metaphysically possible that human persons are purely corporeal, thinking animals. But he does not think that we could ever know this to be the case; nor does he think that this is the most likely possibility.

16 Essays

on the Intellectual Powers of Man , Essay Three, Chapter four (1983.214).

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On the third supposition listed in §21, a person is neither wholly spiritual, nor wholly animal. Rather, a person is a composite entity, formed when an immaterial spirit is united to a living organism. I contend that this is the view which he later endorses as "the more probable opinion," according to which our consciousness is "annexed to, and the Affection of one individual immaterial Substance" (§25). In the first place, note that this opinion does not claim that a person is an immaterial substance, but rather that a person's consciousness is annexed to or causally dependent upon a single, immaterial substance. And in the second place, towards the end of §25 he reiterates his contention that persons-who are conscious in virtue of their possession of an immaterial thinking substance-have bodily parts, writing that "any part of our Bodies vitally united to that, which is conscious, makes a part of ourselves." Although he does not say so in §25, we can safely assume that at least in typical cases, a person will be the union of a single immaterial spirit and a single organism, and in particular to a single man . I thus conclude that his tentative affirmation of the "more probable opinion" in §25 amounts to an affirmation of the third supposition listed in §21, according to which Socrates is "the same immaterial Spirit united to the same Animal." Descartes is also committed to thesis that human persons are soul/body composites, despite the fact that frequently appears to describes himself as an immaterial spirit. For he repeatedly insists that human persons are composed of an extended substance and a thinking substance which have been substantially united into a single thing." Indeed, he explicitly denies the first of these suppositions, for he thinks that this view cannot account for our sensations of pain or pleasure. Thus in the Sixth Meditation Descartes writes: Nature also teaches me, by these sensations of pain, hunger, thirst and so on, that I am not merely present in my body as a sailor is present in a ship, but that I am very closely joined and, as it were, intermingled with it, so that I and my body form a unit. If this were not so, I, who am nothing but a thinking thing, would not feel pain when the body was hurt, but would perceive the damage purely by the intellect, just

17 Some of his clearest statements to this effect occur in his correspondence. See, for example, his letter to Princess Elizabeth which is dated 28 June 1643 (CSM-K 1II:226-9; AT III:690-93), and his letters to Regius which are dated December 1641 and January 1642 (CSM-K 200f and 205-9; AT 1II:460f and 491-509). See also his Comments on a Certain Broadsheet (CSM 1:299; AT VIlIB 351). For a recent defense of the view that a Cartesian man is a substance which is composed of an extended body and a immaterial soul, see Paul Hoffman (1986).

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CHAPTER FOUR as a sailor perceives by sight if anything in his ship is broken." (CSM 11:56; AT VII:81)

Thus, it looks like Locke and Descartes both reject the first of these suppositions, and embrace versions of the third, although Locke's endorsement is more tentative, since unlike Descartes, he is not willing to rule out the possibility that human persons are purely material, thinking animals. Even if Locke and Descartes share the same account of what human persons are ultimately composed of, Locke does not accept the theory of personal identity which Descartes evidently attempts to derive from this account. According to the theory of personal identity which is widely attributed to Descartes-which Edwin McCann refers to as the immaterial substance theory-the person PI (at tl) is the person P2 (at t2) if and only if PI and P2 share the same soul." It is pretty clear that Locke takes this theory to be the chief rival of his own, as evidenced by his repeated insistence that personal identity does not depend upon sameness of (thinking) substance, but upon something else. 20 His account of what this something else involves follows a common pattern: just as he thinks that the organism 0\ (which is F at t\) is the organism 02 (which is G at t2) if and only if 0\ and 02 share the same life, he thinks that the person p\ (who is F at t\) is the person P2 (who is G at t2) if and only if p\ and P2 share the same consciousness. He has thus developed a strong analogy between the role which is played by life in the case of organisms and the role which is played by consciousness in the case of persons. Or as McCann elsewhere nicely puts it, for Locke, "consciousness is the life of persons" (1987, 68). In what remains of Part Three I examine Locke's use of this analogy between life and consciousness, particularly in defending his account of personal identity against the immaterial substance theory. I argue that his use of this analogy helps us to settle the question of whether Lockean 181t is unfortunate that in the very passage in which Descartes is trying to distance himself from Plato's position-that we are immaterial souls which merely use bodies-he uses the pronoun '1' to refer to his soul. For a more detailed explanation of this contention, see John Cottingham (1985). 19 Given the ubiquity of this attribution, it is surprisingly difficult to find any texts in Descartes affirms or commits himself to the immaterial substance theory . Indeed, McCann goes as far to say that "Descartes nowhere explicitly formulates a theory of personal identity" (1986 : 458) , and again that "nowhere in his works is such a theory explicitly formulated, let alone defended" (459). This might wen be the case with respect to his published work s, but in his correspondence he quite definitely commits himself to the immaterial substance theory. See, in particular, his letter to Fr. Denis Mesland which is dated 9 Feb 1645 (CSM-K 1ll:2423; AT IV: 166-7) . 20 See, for example, §9 (335 : 19); §1O (336 : 9-32); §II (337: 5-9); §12 (337 : 16-18) ; §16 (340 : 28-30), (341 : 8-14); §19 (342 : 12-17) ; §23 (344 : 25-34); and §25 (346 : 1-8).

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organisms and persons have both spatial and temporal extent. I begin by showing that his development of this analogy, in conjunction with his account of what consciousness might do in the case of persons, commits him to the thesis that an organism is partly composed of its constituent masses, which implies that the organisms in his ontology have both spatial and temporal extent. I subsequently argue that if Lockean organisms have both spatial and temporal extent, then so do the persons who are at least partly composed of these organisms. 2. Consciousness as the "life " ofpersons

Although Locke thinks that persons typically possess a single, persisting soul, he contends that a person does not persist in virtue of this fact. Indeed, he contends that sameness of constituent thinking substance (= soul) is neither necessary nor sufficient for personal identity: it is not necessary, since it is possible for one person to possess different souls at different times, and it is not sufficient, since it is possible for one soul to belong to different persons at different times. Let us discuss these positions in tum, starting with the latter. In § 14 takes up the question of whether a single immaterial substance might be associated with distinct persons living at wholly different times. Our answer to this question, he thinks, depends upon our another to another, namely, whether the same immaterial being, being conscious of the Actions of its past Duration, may be wholly stripp'd of all the consciousness of its past Existence, and lose it beyond the power of ever retrieving again: And so as it were beginning a new Account from a new Period, have a consciousness that cannot reach beyond this new State.

That is, the question of whether it is possible for an immaterial, thinking substance to be associated with more than one person depends upon whether it is possible for such a substance to be in a state of permanent and total amnesia with respect to its earlier conscious episodes. He is convinced that those who affirm the preexistence of their souls will grant that such an amnesic state is, in their case, not merely possible, but actual. On the assumption that such a state is possible, Locke's refutation of the immaterial substance theory involves the following sort of case. Suppose, with the Christian Platonists and Pythagoreans, that you have a soul which has existed continuously, say, for at least the past ten thousand years. Suppose, in addition, that your soul had previously belonged to other men, and in particular, that it belonged to either Nestor or Thersites, both of whom fought in the siege of Troy. Now he raises yet another question: how must

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you take yourself to be related to one of these individual s? In particular, can you, who have "no consciousness of the Action s either of Nestor or Thersites" conceive of yourself as being "the same person with either of them"? His answer is compelling: there is no way you could reasonably take yourself, as some might now say, "to have been Nestor or Thersites in a past life." Since you are not conscious of the thought s and actions of either, you cannot now claim them as your own. Indeed , you must say, for example, that Nestor's thoughts and actions and your thoughts and actions are necessarily those of different persons, even if both his thoughts and actions and yours are ultimately dependent upon a single, immaterial thinking substance. Thus Locke concludes that having the same soul as Nestor would no more make you the same person as Nestor as sharing a single atom would. Having briefly examined Locke's claim that sameness of thinking substance is not sufficient for personal identity, let us tum to the more radical claim that sameness of thinking substance is not even necessary for personal identity. Locke first confronts the immaterial substance theory of personal identity in § 10, ju st after stating and briefly defending his "psychological continuity" account of personal identity in §9. In §10 he notes that the sporadic nature of our memory raises doubt s about whether the same thinking substances existed within and between the various gaps in our memory. Although he is not dismis sive of this question, he takes it to be irrelevant to the topic at hand. Thus he writes in § I0 that "the Question being what makes the same Person , and not whether it be the same Identical Substances, which always thinks in the same Person , which in this case matters not at all." That is, subsequent to making a distinction between the question of whether (i) the person PI (at tl) is identical with the person P2 (at t2), and that of whether (ii) PI and P2 share the same thinking substance, he states that one's answer to the second question is not relevant to one's answer to the first. In defen se of this claim, he immediately presents the following argument: Different Substances, by the same consciousnes s (where they do partake in it) being united into one Person; as well as different Bodies, by the same Life are united into one Animal, whose Identity is preserved, in that change of Substances, by the unity of the one continued Life. For it being the same consciousness that a Man be himself to himself, Persona/Identity depends on that only, whether it be annexed only to one Individual Substance, or can be continued in a succession of several substances. (§ 10, 336:14-21)

Here Locke argues that it is possible for a person to be associated with a series of successively existing thinking substances, just as is possible for an organism to be associated with a series of successively existing bodies. In

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particular, he seems to be arguing that it is at least possible that consciousness plays the same role in the case of persons as life plays in the case of organisms. That is, just as a series of successively existing, suitable arranged masses can constitute a single organism by being caught up in the same life, a series of suitably disposed thinking substances could constitute a single person by being, as it were, caught up in the same mental life. Thus, Locke's rejection of the immaterial substance theory-the thesis that PI is pz only if p, and pz share a single same thinking substance-rests upon his analogy between the role which life plays in the case of organisms and the role which consciousness might play in the case of persons. Locke's use of this analogy between consciousness and life draws his attention back to the relationship between a persisting organism and its corresponding series of constituent masses. For this analogy to have any force, the "different Bodies" which he mentions in the above passage from § I0 must be a reference to distinct, successively existing masses. I think that the same holds true for his contention that continuity of life enables an animal to persist through the inevitable "change of substances". That he is here using 'substances' to refer to an organism's successively existing constituent masses comes out even more clearly at two junctures in § 12. In the first place, consider his insistence that the issue of whether personal identity requires sameness of thinking substance "can be no question at all for those who place Thought in a purely material, animal, Constitution, void of an immaterial Substance." Why can't this question arise on such a view? Because the Hobbesian would be forced to conceive of personal identity as being "preserved in something else than Identity of Substance ; as animal Identity is preserved in Identity of Life, and not of Substance." On his view, someone who accepts Hobbes' contention-that human persons are purely material, self-conscious organisms-eannot take personal identity to require sameness of thinking substance. For on this contention, we should never have the same thinking substance at any two successive moments, since thinking substances would also be suitably arranged corporeal substances, which are themselves being constantly replaced by numerically distinct, qualitatively similar substances. In the second place, consider his assessment of the "Cartesian" response to the Hobbesian position: Those, who place thinking in an immaterial Substance only, before they can come to deal with these Men, must shew why personal Identity cannot be preserved in the change of immaterial Substances, or variety of particular immaterial Substances, as well as animal Identity is preserved in the change of material Substances, or variety of particular Bodies. (337: 18-2).

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Here Locke is obviously reaffirming the analogy which he just gave in § 1O. That is, he is claiming that even if thinking substances tum out to be immaterial substances, a person's mental life-and hence the person himself-might be successively constituted by a variety of thinking substances, just as an animal's biological life is "preserved in the change of material Substances, or variety of particular Bodies." Given the force of this analogy, I think that there is no escaping the fact that each of these "particular Bodies" is a suitably arranged mass of matter. For otherwise there is no real comparison to be drawn between immaterial substances on the one hand and material substances on the other. Locke's contention that consciousness might play the same role in the case of persons (with respect to successively existing thinking substances) as life in fact plays in the case of organisms (respect to successively existing masses of matter) is an enormously fruitful one, both for his purposes, and for ours. It is fruitful for him, since it enables him to defend his theory against the most plausible aspect of the immaterial substance theory." And it is fruitful for us, since it enables us to fix the relationship between an organism and its constituent masses . In particular, it enables us to conclude that an organism is partly composed of its constituent masses, which implies that the organisms in his ontology have both spatial and temporal extent. And this, I shal1 argue, further implies that the persons in Locke's ontology must also have spatial extent. 3. What consciousness might do On Locke's account of identity for organisms, a persisting organism and its constituent masses are related in one of two ways: an organism is either whol1y composed of each of these masses, in succession, or it is partly composed of each, and hence whol1y composed of the entire series of masses . As we also saw, given only his explicit treatment of organisms in §§3-8, we have no basis for favoring one of these possibilities as his "official" position. In what remains of Part Two I argue that Locke's affirmation of the above analogy enables us to settle the question of how an organism is related to its successively existing constituent masses. Simply put, this analogy tel1s us that continuity of consciousness might do for persons what continuity of life in fact does in the case of organisms. So we can learn more about the role which he takes life to play in the case of organisms by taking a closer look at what he thinks consciousness might do in the case of persons. 21 Once it is granted, as Locke does, that thinking substances are enduring, immaterial substances, it is quite plausible to suppose that person PI (at (1) is identical with the person P2 (at (2) only if PI and P2 share the same immaterial thinking substance.

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I think that it has to be admitted, however, that the passages quoted thus far-from §§10 and 14-are not tremendously helpful in this regard. The first states that a stream of consciousness could be "continued in a succession of several substances," while the second states that a person's continued existence could be "preserved in the change of immaterial substances." These passages are not helpful because they only license the conclusion that a person might be associated with a series of thinking substances, just as an organism is associated with a series of masses. In particular, they do not shed much light either upon how a persisting person would be related to these successively existing thinking substances, or upon how these substances would be related to one another. At least at first glance, we seem to have exactly the same two possibilities here that we had in the case of organisms : for all he has said thus far, a person 's cognitive nature might either be (i) wholly constituted by each of these immaterial substances, in succession, or (ii) partly composed of each, and hence wholly composed of the entire series of thinking substances. And just as we saw earlier, if the first possibility obtains then this person's cognitive nature will lack temporal extent, whereas if the second obtains one's cognitive nature will have temporal extent. Although the above passages from §§10 and 14 do not enable us to confidently chose one of these as his "official" view, I think that the passage from § 10 provides some support for conclusion that Locke favors the second possibility. For there he speaks of these successively existing, psychologically continuous thinking substances as being "united into one Person." The suggestion seems to be that they are being united into one person in the sense that they are being collectively united into this person. And that would clearly preclude the first possibility (that a person's cognitive nature is wholly constituted by each of these substances) and require the second (that a person's cognitive nature is partly composed of each of them, and hence wholly composed of the entire series). But it is conceivable that when Locke says that these successively existing thinking substances would be "united into one Person," he means that each of them would be united to this person, in succession, which would evidently preclude the second possibility and require the first. While I am not aware of any passages which suggest that he embraces this line of thinking, it is not hard to find passages which connect him to the contrary view. That is, it is not hard to find passages in which he embraces or at least commits himself to the thesis that if a person's mental life were the product of successively existing thinking substances, then one's cognitive nature would be partly composed of each of these substances, and wholly composed of the entire series of substances. In defense of this claim, let us tum to passages from §§13, 16, 17,23, and 25.

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By he time he gets to §13, Locke has alread y embraced the view that a person ' s mental life might involve a series of successively existing thinking substances. In § 13 he points out that this is possible only if "the consciousness of past Action s can be transferr'd from one thinking Substance to another. " He subsequently points out that this transfer of conscious states requires that what one is consciousness of now, with respect to some past action, is not some sort of direct awareness of this action ("consciousness of the same individual action"), but rather a "present representation" of this action.f In connection with this possibility, he concludes § 13 in the following manner: If the same consciousness (which, as has been shewn, is quite a

different thing from the same numerical Figure or Motion in a body) can be transferr'd from one thinking Substance to another, it will be possible that two thinking substances may make but one Person.

I am here interested in Locke' s claim that in such a case, the "two thinking substances" would "make but one person." The force of this suggestion, I think, is that in such a case, these successively existing thinking substances would together constitute this person . And that would require that this person be partly compo sed of each , and hence wholly compo sed of the aggregate, instead of being wholly composed of each, in succession. While 22 It seems pretty clear that Locke's suggestion that conscious states can be transferred from one thinking substance to another is the impetus behind Kant's elastic ball analogy in a footnote to the First Edition version of the Paralogisms (A 363f). The footnote runs as follows:

An elastic ball striking another such ball in a straight direction communicates to that ball (if we take account merely of the positions in space) its entire motion and hence its entire state. Now let us-by analogy with such bodies-assume substances one of which imbues the other with presentations along with the consciousness of these. We shall then be able to think of an entire series of such substances: the first would communicate its state, along with the consciousness thereof, to the second substance; the second would communicate its own state, along with the state of the previous substance, to the third ; and the third substance would similarly communicate to yet another the states of all the previou s substances, along with its own state and the consciousness of all of them. Hence the last substance would be conscious of all the states of the substances that had changed before it as being its own states, becau se these states would have been transferred to it together with the consciou sness of them. Despite this, however, that substance would not have been the same person in all these states. [1996 , 397f n.99]

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this is probably not the only tenable way of reading this passage, I don't think this can be said for the passages to follow. In §16, for example, Locke's discussion of the unity relation between successively existing thinking substances evidently commits him the view that I have just recommended in connection with § 13. After reaffirming the falsity of the immaterial substance theory of personal identity he writes: ' tis plain [that] consciousness, as far as ever it can be extended , should it be to Ages past, unites Existences, and Actions, very remote in time, into the same Person, as well as it does the Existence and Actions of the immediately preceding moment: So that whatever has the consciousness of present and past Actions, is the same Person to whom they belong. (§16, 340:30-35)

In this passage Locke contends that by being caught up in the same "stream of consciousness," distinct, successively existing objects are united into a single, persisting person. Now in saying that these distinct substances are united by consciousness, he cannot be suggesting that these "existences" are thereby becoming identical with one another. He must instead be suggesting that are being collectively united with one another, and in particular, that they are united with one another across time, with the implication being that the product of this union is none other than the person whose consciousness effects this cross-temporal unity Consider now the following passage from §23: Nothing but consciousness can unite remote Existence s into the same Person, the Identity of Substance will not do it. For whatever Substance there is, however framed, without consciousness, there is no Person. (§23, 344:13-16)

Here Locke contends not merely that consciousness can unite successively existing thinking substances into a single, persisting person, but that only consciousness could pull this off. Now why might this be the case? While consciousness may not be the only relation which is capable of extending backwards in time, it is clearly the only relation which can do so in a way that makes these remotely existing substances to be psychologically continuous with one another. And it is precisely this continuity between remotely existing substances which collectively unifies them across time into a single, persisting person. Locke begins § 17 by reiterating his contention that persons need not be simple substances, even if they are essentially conscious substances: Selfis that conscious thinking thing, (whatever Substance, made up of whether Spiritual , or material, Simple, or Compounded, it matters not) which is sensible, or conscious of Pleasure and Pain, capable of

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He subsequently points out that it is through consciousness that certain bodily parts have become parts of oneself. He thus writes that "every one finds, that whilst comprehended under that consciousness, the little Finger is as much a part of it self as what is most so." While bodily parts exist simultaneously, he goes on to make the same point with respect to "Substances remote in time". Thus Locke : As in this case it is the consciousness that goes along with the Substance, when one part is separated from another, which makes the same Person, and constitutes this inseparable self: so it is in reference to Substances remote in time. That which the consciousness of this present thinking can join it self, makes the same Person, and is one self withit, and with nothing else; and so attributes to it self, and owns all the Actions of that thing, as its own, as far that consciousness extends, and no father; as everyone who reflects will perceive. [§ 17] Locke evidently takes consciousness to be doing double duty here, since it plays one role with respect to one presently existing bodily parts, and another with respect to "substances remote in time." That is, as consciousness is manifested in the form of one's present bodily sensations, a person is extended in space, but only as far as these sensations reach. And as consciousness is manifested in the form of memory-the faculty whereby one has present representations of past thoughts and actions-a person is extended backwards in time , but only to those substances whose thoughts and actions can be represented to the person at that time. Now if, as is being supposed, these previously existing substances are distinct from the one which is thinking presently, then they could only be incorporated into this person as distinct, successively existing parts. Recall, moreover, that Locke is presently concerned with showing that persons need not be simple substances. He is, in effect, describing two different ways in which persons might be composites: they might be composites whose parts existing simultaneously, and they might be composites whose parts exist in succession . Finally, Locke clearly uses the word part in connection with those objects which fall within the reach of one's present bodily sensations, and I take his suggestion that things work in the same way "in reference to Substances remote in time" to indicate that he also takes these previously existing substances to be parts of self whose consciousness extends to them. In defense of this reading, let us now tum to §25, where he clearly and explicitly speaks of these previously existing thinking substances as parts of the persisting person.

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At the start of §25 Locke returns to the topic of a person' s (presently existing) bodily parts. In the following passage he contends that a person has only those parts of which he is presently conscious, and that one has these bodies as parts only as long as one's consciousness extends to them. Thus Locke: The same continued consciousness, in which several Substances may have been united, and again separated from it, which, whilst they continued in a vital union with that, wherein this consciousness then resided, made a part of that same self. Thus any part of our Bodies vitally united to that, which is conscious in us, makes a part of ourselves.

In the last sentence of §25 he reiterates this claim and then goes on to make a similar statement with respect to one's relationship to any previously existing substances: Any Substance vitally united to the present thinking Being, is a part of that very same self which now is: Any thing united to it by consciousne ss of former Actions makes also a part of the same self, which is the same both then and now.

Let us suppose, with Locke, that one's mental life is not based upon a single, persisting mental substance, but rather upon a series of mental substances, each of which transfers its states to its successor in the appropriate way. Let us suppose, say, that over a period of time Fred's mental life has been the product of ten, successively existing mental substances, s" Sz, S3, " ,SIO, so that his mental life was upheld by s, at t" by Sz at tz, and so on. Let us further suppose that Fred is presently associated with the last of these, and that he has clear and undistorted representations of the thoughts and actions of all of the previous substances. Here, then, is our most pressing question: how is Fred related to these substances? In particular, is his cognitive nature wholly composed of each of them, in succession, or is it partly composed of each, and hence wholly composed of the aggregate? We are now in a position to confidently state that Locke embraces the second possibility and rejects the first. According to this passage, s" su and S3 are distinct parts of him "both then and now" . That is, s, and Sz are distinct proper parts of him now. The only alternative is to say that SI was an improper part of him at t" that Sz was an improper part of him at tz, and so on. But this reading of Locke would be completely untenable. In the first place, he does not have the concept of an improper part. But even if he did, the clear implication of these passages is that these substances are parts of him at tlO, and this is clearly incompatible with s,'s being an improper part of him at t" to say nothing of S IO' S being an improper part of him at tlO. I thus conclude that on

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Locke's view, in the event that a person's mental life is the product of successively existing thinking substances, then this person's cognitive nature would be the temporally extended aggregate of these substances. Now in giving the above argument I have been assuming that these thinking substances do not continue to exist once they have "transferred" their mental states to their successors." There is at least some initial justification for this assumption. For on my view, Locke is developing an analogy between (i) an organism and its constituent masses and (ii) a person and his constituent thinking substances, and I take use of this analogy to suggest that a thinking substance ceases to exist once it has transferred its conscious states to another, just as a mass ceases to exist once it has passed on one or more of its constituent atoms. Perhaps I have no right to make such an assumption, however. For, it could be argued, not only does he fail to suggest that they do cease to exist to exist subsequent to this transfer, he is not in a position to say that they must do so. Let us suppose, for the sake of argument, that s\ does not cease to exist once it has transferred its states to S2, and that the same holds true for S2 and its successors. That is, let us suppose that Sl, S2, S3 .. .SIO all exist before tl, after tlO, and at every moment between these times. This assumption requires that these thinking substances persist by enduring . For should they persist by perduring, then we would have to think of them as numerically distinct, non-overlapping soul-stages. And if Sl, S2, and S3 are successively existing stages, then it would be impossible for them to exist at tlO. SO Sl, S2, S3 ...SIO all exist at tlO only if they are enduring substances. But in that case it would be impossible to think of Fred's cognitive nature as being composed of the cross-temporal "aggregate" of these substances at tlO. For simultaneously existing objects can no more be diachronically compounded than spatially co-located objects can be spatially compounded. Suppose that two or three spatially co-located objects exist, and that these objects have been someone united into a single thing . Clearly this would not be an instance of spatial compounding, since the "aggregate" of these objects would not have any more spatial extent than either of its parts . Similarly, it might well be possible for Sl, S2, S3" .SIO to be compounded into a single thing at tlO. But this couldn't be an instance of diachronic compounding, since the aggregate of these objects (at tlO) would not have any more temporal extent than any of its parts. Indeed, the aggregate of these objects would not have any temporal extent whatsoever. And, I take it, there can no more be a diachronically compounded object which lacks temporal extent than there can be a spatially compounded object which lacks spatial extent.

23 I am indebted to Don Garrett and Thomas Holden for bringing this assumption to my attention.

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So if St. S2, S3" .SIO are enduring substances, all of which exist at tlO, then they cannot be united in the way that Locke suggested that a person ' s constituent thinking substances might be united at tlO. That is, they could not possibly be successively existing proper parts of Fred ' s cognitive nature, so that SI (and only SI) constitutes Fred 's cognitive nature at t i , S2 (and only S2) constitutes his cognitive nature at t2, and so on. Instead, each of these substances would be a proper part of Fred at all of these times. Can we thus conclude from this that these substances can be so united only if they are temporally extended soul-stages, so that SI perdures from t1 to t2, S2 perdures from tz to t3, and so on? I don 't think so. For it is conceivable these substances persist by enduring, but without temporally overlapping, so that s) endures from t1 to t2, S2 endures from tz to t3, and so on. Would the "aggregate" of these substances have temporal extent, in such a case? I think that it would. For the aggregate would exist from t1 to tlO, but only by having one part which exists from t) to t2, another which exists from ti to t-; and so on. Since the aggregate of these substances would exist from t) to tlO only by having different parts at these times , it would have to be a perduring, temporally extended object, even though its constituent substances lack temporal extent (since they persist by enduring). It thus looks as if enduring substances-which lack temporal extent--can be diachronically compounded into an object which has temporal extent, just as mathematical points-which lack spatial extent--can together constitute a line, which obviously has spatial extent. I thus conclude that S t. S2, S3 ...SIO can compose Fred 's cognitive nature in the way that Locke suggests only if they are successively existing objects which persist either by perduring or enduring, but without temporally overlapping. And regardles s of the manner in which these substances persist, the cross-temporal aggregate of these substances must have temporal extent.

4. The temporal extent of Lockean organisms We have already seen that Lockean persons have spatial extent , and I have just shown that they might also have temporal extent. In this section and in the one to follow I argue that his contention that persons might have both spatial and temporal extent implies that they do have both spatial and temporal extent. In particular, I argue that this contention indirectly implies that Lockean persons have both spatial and temporal extent , since it directly implies that Lockean organisms have both spatial and temporal extent. In this section I defend the latter claim. Recall, first, that on his view, each persisting organism is associated with a series of successively existing masses of matter. Recall, in addition, that his explicit treatment of persistence in the case of plants and animals (in §§3-8) does not enable us to

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determine precisely how a persistmg organism is related to these successively existing masses. From that vantage point, we can only say that an organism and its constituent masses are related in one of two ways: the organism is either (i) wholly composed of each of these masses, in succession, or (ii) partly composed of each, and wholly composed of the temporally extended aggregate. Here is where the consciousnessllife analogy comes into play. First, in response to the immaterial substance theory of personal identity, he argues that a person's past and present mental life might be grounded in series of thinking substances, just as an organism's life is grounded in a series of appropriately arranged masses of matter. Moreover, in §§10 and 13 he argues that in such a case, consciousness would play the same role in the case of persons (with respect to these successively existing thinking substances) as life in fact plays in the case of organisms (with respect to these successively existing masses of matter). So in order to see what role he takes life to play in the case of organisms, we need only examine the role which consciousness would play under analogous circumstances. And in §§13, 16, 17,23, and 25 he repeatedly insists that should one's past and present mental life be grounded in a series of psychologically continuous thinking substances, this person's cognitive nature would be partly composed of each of these substances, and hence wholly composed of their temporally extended aggregate. Given his contention that consciousness might do for organisms what life in fact does for organisms, the implication for his account of organisms is clear: by participating in the same life, a series of successively existing constituent masses are diachronically combined into a single, temporally extended organism. A Lockean organism is thus the temporally extended aggregate of its successively existing constituent masses of matter. As diachronic compounds, Lockean organisms must obviously have both spatial and temporal extent. Now as with logically implications generally, this one holds whether Locke is aware of it of not. But was he? We cannot say. As Karl Popper has pointed out, theories are like children in the sense that no one-not even their progenitors-fully understand them. For as with children, theories inevitably take on lives of their own, and behave in ways that one could not have anticipated (1972, 299). I would like to think that he was aware of this implication at some level of his understanding, but I am not claiming that he was fully aware of this implication, still less am I claiming that he was aware of its many consequences. As far as I am concerned, the question of how clear he was about this point (if at all) is not philosophically important. Rather, the important questions concern the (objective) metaphysical implications of this position and how he would (and should) have responded to them. Would he have embraced the view that organisms have both spatial and temporal extent? Or would he have

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avoided this implication by retracting his contention that consciousness might do in the case of persons what life in fact does in the case of organisms? The answer to these questions, I should think, depends upon what the most relevant consequences are. In what remains of this chapter I shall develop one such consequence, and the subsequent chapters I shall develop several others. At bottom I argue that he would have found the consequences of a four-dimensional ontology to be markedly superior to those of a three-dimensional ontology. 5. The temporal extent ofhuman persons

Having established that Lockean organisms have both spatial and temporal extent, I shall now defend the claim that if Lockean organisms have both spatial and temporal extent, then so do Lockean persons. Recall, first, that in §21 Locke lists three possible theories with respect to the relationship between one's mind and one's body. We are, on his view, either (i) spirits, (ii) purely material thinking organisms, or (iii) spirit/organism composites. Since he thinks that human persons have bodily parts, however, he must reject the first theory. And while he tentatively endorses the third, calling it "the more probable opinion" in §25, he clearly leaves open the possibility that persons are not even partly composed of immaterial spirits, but are instead purely material, thinking organisms. It is not hard to see that persons must have both spatial and temporal extent on either of the two theories which he thinks has a chance of being true. If the second theory listed in §21 is true, and persons are purely material, thinking animals, then persons are diachronically compounded substances like all other organisms. It is clear, moreover, that persons must have temporal extent even if they are partly composed by a temporally extended organisms. For as Chappell points out, If persons are indeed partly made up of atoms and of masses of matter, the same atoms and masses that make up the human beings associated with them, then persons are also made up in each of the two ways, synchronic and diachronic, that such components combine to form living creatures. (1990, 29)

In other words, if persons are partly composed of immaterial spirits, and partly composed of (diachronically compounded) organisms, then persons must also be diachronic compounds. In such a case, however, persons would not be temporally extended in precisely the same way that organisms are, for while the material part of a person has temporal extent, the

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immaterial part presumably does not." In other words, on Locke' s "more probable" opinion , a human being consists of an enduring spirit which has been united to a living, perduring body, and this spirit can be united to a diachronic ally compounded body only by being successively united to each of its constituent (temporal) parts, the result of this union must also be a perduring object. " Since Lockean persons are either wholly or partl y composed of (diachronically compounded) organsims, and since persons tum out to have both spatial and temporal extent either way, I conclude that Lockean persons have temporal extent, simpliciter.26 One of the most remarkable feature s of Locke ' s identity chapter is his use of thought experiments and problem cases to explain and defend his position. The se cases are radical indeed. Some cases, for example, present us with a single person who is somehow "shared" by two men, while others present us with a single man who is somehow "shared" by two persons. In what is perhaps his strangest case, a person literally continues to exist in the form of a consciou s, severed finger. So far I have largely steered clear of these cases. Given the importance which he himself seems to have place in them, however, I don't think that they can safely be ignored. Before we can tum to them, however, I need to say a bit more about the account of organisms and persons to which Locke has apparently committed himself. 6. Organisms, persons, and their temporal stages

I have argued , in essence, that a Lockean organ ism is the temporally extended sum of its short-lived organism stages, and similarly that Lockean persons are the temporall y extended sums of their shorter-lived person stages. Obviously this interpretation is coherent only if the concept of an object- stage is coherent. But though everyone knows what an animal is, one might well be in the dark about what an animal-stage is. To say that these stages are temporal parts is course not very helpful , but it is a start. For we know what parts are in the case of spatially extended item s, and there is a clear analogy between the spatial parts of spatially extended items and the temporal parts of temporally extended items. As I pointed out in the preceding chapter, once we have the concept of a temporally extended object, the notion of a temporal part is no more problem atic that the notion of a spatial part. As Heller nicely puts it, a (proper) part of a fourFor a brief discussion of these so-called "mixed cases", see David Lewis ( 1986, 202). On the Cartesian account of persons and personal identity, a human being consists of a single, enduring spirit which has been united to a single living body, and the product of this union would itself have to be an enduring object. 26 A similar view is expressed by Alston and Bennett (1988, 45f), Shoemaker (1984, 81), and Bennett (1994, I05f). 24

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dimensional object 0 is one which is smaller than 0 on at least one of its four dimensions. Whereas a spatial part of 0 is one which is smaller than 0 along at least one of its spatial dimensions, a temporal part of 0 is one which is smaller than 0 along its temporal dimen sion (1990 , 12). Given this conception of a temporal part, it follows that the temporal parts of spatially extended objects are themselves spatially extended. But must they also have temporal extent? I think that he would have difficulty answering this question , since he claims to be incapable of forming an idea of any real existence "with a perfect negation of all manner of Duration" (II.xv .ll). In other words, he cannot conceive of a spatially extended object which does not exist for any length of time . I suspect, moreover, that he would have found temporal parts with zero temporal extent to be of absolutely no use: for just as a spatially extended object cannot be composed of parts which have zero spatial extent, temporally extended objects cannot be composed of parts which have zero temporal extent. Thi s last point can be reached from another direction. In II.xv.9 Locke claims that it is of the very nature of both space and time to be composed of parts. In addition, he claim s that every part of space or time is infinitely divisible, so that "every part of duration is duration too ; and every part of Extension is Extension". According to Locke, no matter how long one were to continue dividing a unit of time or space into halves , he would still be left units possessing non-zero temporal extent. This, in tum, suggests that he would not allow for the existence of parts without any temporal or spatial extent. Although I think that he would deny the existence of temporal parts which do not have any temporal extent, I do not think that he is obliged to say how much temporal extent is possessed by an object's absolute temporal parts. Indeed, if there are no temporal atoms , it may not even make sense to speak of an object' s absolute temporal parts: if we will never find a temporal part which cannot be subdivided still further, then we will never find a temporal part which doe s not itself have temporal parts. But though each of an organism' s stages is composed of still smaller stages, Locke has grounds for treating as absolute those organism-stages which are constituted by single masses of matter. For as we have seen, his account of diachronic identity for organisms is told solely in terms of masses. Since persons are also composed of masses, might he similarly treat single-mass stage s as a person ' s absolute temporal parts? I don 't think so. For Locke thinks that persons are "intelligent agents capable of a Law, and Happiness and Misery" (§26). If persons are composed of stages, then persons are moral agents only if person-stages are also moral agents. For if I existed three days ago in virtue of the fact that one of my stages existed three days ago , then I can be morally responsible for an action committed

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three days ago only if one of my stages is responsible for this action, which requires that these stages last long enough to intentionally perform certain actions. Thus I think that he would have to agree, with Lewis, that a personstage "does many of the same things that a person does: it talks and walks and thinks, it has beliefs and desires, it has a size and shape and location" (1983, 76). Since living organisms undergo a fairly rapid turnover of constituent atoms, it is pretty clear that Locke's pragmatically absolute person-stages last much longer than single-mass organism-stages. But this is not to say that person-stages can do everything that a person does, for as Lewis goes on to point out that since person-stages do not last for too long, they cannot do those things "that a person does over a longish interval" (1983,76). Under what conditions would two successively existing person-stages be stages of a single person? His suggestion in §§ 16, 17, and 23 that these 'existences' might be remote from one another indicates that he does not require them to be temporally contiguous. Rather, he only requires that they be psychologically contiguous, and he seems to think that two person-stages can be psychologically contiguous without being temporally contiguous. This, in tum, suggests that he does not think persons need to exhibit spatiotemporal continuity, the way atoms and organisms (including men) do. According to Locke, two successively existing thinking substances are part of the same person if, and only if, the second substance is conscious of the actions of the first. Since Locke is committed to a four-dimensional account of organisms, and since persons are either wholly or partly composed of these organisms, he is also committed to a four-dimensional account of persons. But if Lockean organisms and persons both possess both spatial and temporal extent, wherein lies the difference between men and persons? The difference must lie in the relation between their successively existing parts. Whereas two animal -stages are parts of a single animal if and only if they partake of a common life, two person-stages are parts of a single person if and only if they partake of a common consciousness. Given the role played by life in the case of organisms, let 'life-relation' stand for the relation which obtains between the various temporal parts of an organism. Similarly, given the role played by consciousness in the case of persons, let 'consciousness-relation', stand for the relation which obtains between the various temporal parts of a person. Thus for Locke, a man is a maximally life-related aggregate of man-stages, and a person is a maximally consciousness-related aggregate of person-stages.

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While Locke thinks that men and persons are distinct entities," he also think s that they are intimately related in some way. Unfortunately, he never explains precisely how they are related. If persons and men are both the four-dimen sional sums of their temporal parts, I submit that their relationship consists in the fact that they are capabl e of sharing temporal parts. On this account, a single temporal part can be both a man-stage and a person-stage. To put this point somewhat differently, some person-stages can also be man-stages, and some man-stage s can also be person-stages. Moreover, we should expect that in typical cases, every animal stage which is also a stage some person will be the stage of the same person, and conversely. With these points in hand, let us tum to Locke's thought experiments and problem cases. III. LOCKE'S THOUGHT EXPERIMENTS AND PROBLEM CASES

As I have already briefly noted, one of the most remarkable features of Locke's identity chapter is his use of thought experiments and puzzle cases. In §§20 and 24, for example, he discusses cases in which he is unable to remember actions which he is truly said to have committed, and he argues that they were committed by a different person, but not by a different man. In §§20 and 23 he discusses the Day ManlNight Man and Mad Man/Sober Man cases, in which one man said to have "distinct incommunicable consciousness at different times," and he argues that this is a case in which two persons are associated with only one man. In §§ 15 and 23 he discusses cases in which two men share a single consciousness, and he takes these to be cases in which one person is intimately related with two men. And in § 17 he discusse s a case in which one ' s little finger is cut off, and one ' s consciousness stays with the finger, instead of with the rest of one's body, and he argues that this little finger-and not the rest of the body-is a continuation of the person who lost the finger. While these cases can be difficult to follow, I belie ve that it is much easier to make sense of them on a four-dimensional interpretation. On this interpretation, Locke's organisms and persons are temporally extended objects which are capable of sharing temporal parts, so that some person-stages are also man-stages and vice versa. Now in an ideal case, each man-stage would be a stage of the same person, and each person-stage would be a stage of the same man. Locke's problem cases can be easily understood as departures from this ideal case. Let us consider them in tum.

This claim is defended in the third section of chapter two, in keeping with Locke' s rej ection of the relative identity thesis. See above, p. 83

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CHAPTER FOUR 1. Cases involving lapses of memory

In §20 Locke anticipates the following objection to his account of personal identity: Suppose I wholly lose the memory of some parts of my Life, beyond a possibility of retrieving them, so that perhaps I shall never be conscious of them again; yet am I not the same Person, that did those Actions, and had those Thoughts, that I was once conscious of, though I have now forgotten them?

This objection is clearly intended to show that Locke's criterion for personal identity is too strict, since it seems to require that one could not have performed an action which one cannot remember having performed. Locke's reply runs as follows: We must here take notice what the word I is applied to, which in this case is the man only. And the same Man being presumed to be the same Person, I is easily here supposed to stand also for the same Person. But if it is possible for the same Man to have distinct incommunicable consciousness at different times, it is past doubt the same Man would at different times make different Persons.

In response to this objection, Locke begins by pointing out that the pronoun 'I' is ambiguous: we might take it to refer to a person, or we might take it to refer to a man. He also suggests that in some cases this pronoun can legitimately be said to refer to both a man and a person, i.e., in cases in which a single man is associated with a single person. In this case, however, Locke contends that 'I' can only refer to the man, for only in this sense can one truthfully utter statements of the form "I performed action x, although I cannot remember doing so." Locke subsequently points out that the person who cannot remember performing this action cannot be the same person who performed it, and consequently that the performer of this action must be a different person. Let 'Paul' stand for the person who cannot remember performing this action, let 'Patrick' stand for the person who did perform it, and let 'Mort' stand for the man to whom these persons are both related. On my interpretation, the present case amounts to simply this: Mort is a maximally life-related aggregate of man-stages. And while all of his man-stages are also stages of some person, they are not all stages of the same person. For at least one of them is a person-stage of Patrick (namely, those which belong to the 'part of his life' which Paul cannot recall), while the rest of them are person-stages of Paul. Now one might well suppose this to be an unnatural and textually unmotivated reading of the above passage. For, one might argue, the mere

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fact that Locke poses his original question in terms of the various parts of a person's life does not license the attribution of temporal parts to a person. Following such philosophers as David Wiggins, Michael Ayers, and Lawrence Lombard, one can consistently deny temporal extent to a person, while attributing temporal extent to a person's life, on the grounds that a person is a substance, which consequently exists----in its entirety-at every moment of its existence, whereas a person' s life (or perhaps better, a person's life-history) is kind of protracted event which is unquestionably composed of temporal parts." In §24, however, Locke provides an answer to a similar question which seems to require that persons themselves have temporal parts. Speaking of an immaterial substance which existed before himself Locke writes: If there be any part of its existence, which I cannot upon recollection join with that present consciousness whereby I am my self, it is in that part of its Existence no more my self, than any other. ..Being. For whatsoever any Substance has thought or done, which I cannot recollect, and by my consciousness make my own Thought and Action, it will no more belong to me, whether a part of me thought or did it, than if it had been thought or done by any other...being any where existing .i"

Now this passage, it seems to me, is best explained in terms of distinct, perduring entities which are capable of sharing temporal parts. Note his use of the phrase 'whether a part of me thought or did it': here Locke virtually says that the (temporal) part of his existence which performed this action does not belong to him qua person, even if it does belong to him qua man. Let 'Lockes' stand for Locke, the person, who cannot recall performing this action, and let 'Lockeq' stand for the man to whom this person is intimately related. Locke- is a maximally consciousness-related aggregate of personstages, and Lockes, is a maximally life-related aggregate of man-stages . Now what he says here, it seems to me, is that none of Lockej-'s stages committed this action, even if one of Locke.,' s stages did. 2. Cases involving two persons and one man

Locke gives several different cases in which two distinct persons are in some way associated with a single man. In § 19 he develops an example of this type in terms of Socrates waking and Socrates sleeping." In §20 he 28 See Wiggins (1980, 25n.12); Ayers (1991, 2:102-8, 319n.15); and Lombard (1986, 12731). 29 In both cases, the ellipses represent the removal of the word 'immaterial' . 30 Locke also discusses this case in 1I.i.1O, in connection with his anti-Cartesian argument

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makes the same point with the help of the Mad Man and the Sober Man, who apparently reappear in §22 as Man Drunk and Man Sober. And finally in §23 makes a similar point in terms of the Day Man and the Night Man. These cases all have one thing in common: they all attempt to show the possibility of a single man's harboring two distinct persons. Locke sets up the last of these cases as follows : Could we suppose two distinct incommunicable consciousnesses acting on the same Body, the one constantly by Day, the other by Night...I ask, whether the Day and Night-man would not be two as distinct Persons, as Socrates and Plato.

According to Locke, the Day Man and the Night Man are numerically distinct persons, which happen to be 'shared' by a single man." But what precisely is the relationship between these two persons and the man with whom they are intimately associated? On my interpretation, their relationship to this man is straightforward. Let 'Milton' stand for the man who is periodically associated with each of these persons. Now Milton is a maximally life-related aggregate of man-stages. Let us divide these stages into two groups: Milton's daytime stages, and Milton's nighttime stages. The relationship between Milton and these two persons can now be put very simply: Milton's daytime stages constitute one maximally consciousnessrelated aggregate of person-stages (the Day Man), and his nighttime stages constitute another (the Night Man).

3. Cases involving one person and two men Locke discusses at least two cases in which a single person is shared by two different men. In § 15 he discusses the case of the Prince and the Cobbler, and in §23 he develops a similar example as a contrast to the Day Man/Night Man case . Whereas the Day ManlNight Man case involves two persons who are alternately associated with a single man, this case involves two different men who are alternately related to a single person. Once again, the four-dimensional interpretation which I have developed easily accounts for this sort of case. Let 'Mark' stand for one of these men, let 'Martin' stand for the other, and let 'Peter' stand for the person to whom they are alternately related. As in the previous case, let us divide the stages of both men into two parts, their Daytime stages and their Nighttime stages, and let us assume that their stages are exactly correlated with one another, that the soul does not always think. As Chappell correctly observes (1989, 78), Locke's use of 'man' in 'Day Man' and 'Night Man' is a misnomer, since these names refer to persons rather than men. Hence to avoid confusion, Locke ought to have used the locutions 'Day Person' and 'Night Person' . 31

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so that Mark's daytime stages occur at precisely the same time as Martin 's, and so on. With these points in hand, the case can be very simply described in the following manner. Peter is a maximally consciousness-related aggregate of person-stages. And while all of Peter's person-stages are also man-stages, they are not all stages of the same man. Rather, Peter is a maximally consciousness-related aggregate of Mark's daytime stages, and Martin's nighttime stages. 4. The case of the conscious, severedfinger

Locke begins § 17 by reiterating the point of § 11, which is that persons are composed of bodily parts, since one's consciousness extends to these parts. Thus Locke writes that "every one finds, that whilst comprehended under that consciousness, the little Finger is as much a part of it self, as what is most so" (§ 17). Now in § 11 Locke's point is that a person can undergo the loss of a limb without ceasing to exist. Though his consciousness no longer extends to the severed limb, he is confident that it would continue to extend to the rest of his body, and this confidence surely is grounded in the fact some people can remember undergoing the loss of a limb. In § 17 Locke illustrates the same point in a much more dramatic way: Upon separation of this little Finger, should this consciousness go along with the little finger, and leave the rest of the Body, 'tis evident that the little Finger would be the Person , the same Person ; and self would have nothing to do with the rest of the Body.

The crucial difference between this case and the one mentioned in § 11 is that in the previous case, one's consciousness is withdrawn from the excised limb, but not from the rest of one's body, while in this case, exactly the opposite occurs: one's consciousness remains with the excised limb, and is withdrawn from the rest of one's body. In both cases, however, Locke thinks that there is a persisting person. In the first case, there is a person who has suffered the loss of a hand, and in the second case, there is a person who has suffered the loss of nearly his entire body. How does my four-dimensional interpretation enable us to make sense of this example? First I need to point out that the case mentioned in § 11 does not represent a significant digression from the ideal case mentioned above, in which a person and a man share exactly the same temporal parts. The only difference would be that at least one of these (shared) stages would be slightly smaller and lighter than the others, by exactly the size and weight of the excised limb. The present case does represent a significant digression from the ideal case, however. For in the first place, there is no reason to suppose that the man who owned this finger ceased to exist upon its being

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cut off. Thus in this case, there is a man who has suffered the loss of his little finger, and a person who has suffered the loss of everything but his little finger. How can we make sense of this? Let 'Michael' stand for the man, and let ' Philip' stand for the person . On my interpretation, Locke ' s missing finger case amount s simply to this. Before the removal of the finger, Michael and Philip share exactly the same temporal parts: everyone of Michael 's temporal parts is also one of Philip' s temporal parts, and vice versa. Subsequent to the removal of the finger, they no longer share temporal parts. If Michael ' s stages are also stages of some person (Locke makes no suggestion one way or the other), they are stages of a person other than Philip. Similarly, if Philip' s stages are also stages of some organic structure (we couldn't call it a man, or even an anima!), they would be stages of an organic structure other than Michael. While a three-dimensional interpretation may be able to make sense of the previous cases, I am convinced that such an interpretation cannot make sense out of this case. In order to see why, let us consider the person who has allegedly suffered the loss of nearly his entire body. Let t] stand for some moment ju st prior to this event, and let t2 stand for some moment shortly after this event. Let 'a' stand for this person at t), and let 'b ' stand for this person 's little finger. Since b is a proper part of a at t ), a and b must be numerically distinct objects at tl' What is the relation ship between a and b at t2, aside from the obvious fact that b is no longer a part of a? If persons like a persist by enduring through time in their entirety, then as Locke presents this case it looks like a is identical with b at tz. and in particular that a and b must be the same person at t» On a three-dimensional interpretation, therefore, Locke is telling us that a and b are distinct at tl , and identical at t» Since Locke knows full well that distinct objects cannot possibly become identical , we must conclude either (i) that he was hopeles sly confused when he developed this case, or else (ii) that he was thinking of persons as persisting objects, but not as enduring objects. IV. CONCLUSION

In this chapter I have argued that the organism s and persons in Locke 's ontology have both spatial and temporal extent. In part one I show that on Locke's view, for each persisting organism there is a corresponding series of successively existing masses. I subsequently show that a Lockean organism is related to its constituent masses in one of two ways: it is either wholly compo sed of each, in succession, or it is partly compo sed of each, and wholly composed of the whole series. Although his initial treatment of organi sms does not enable us to identity which of these possibilities

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represents his considered view, in light of his discussion of personal identity I argue that he embraces the latter. This conclusion depend s upon the following three claims. First, that a person might be associated with a series successively existing of thinking substances, just as an organism is associated with a series of successively existing masses. Second , that in such a case consciousness would jointly unite these thinking substances into a single (temporally extended person). And third, that in such a case, consciousness would play the same role in the case of persons which life in fact plays in the case of organisms. Once I have shown that Lockean organisms have both spatial and temporal extent, it is an easy matter to see that the same must also be true of Lockean persons, since on Locke 's view, persons are either purely material thinking organisms, or organism/spirit composites. Finally, after fleshing out the position which Locke is committed to in a number of ways, I have argued that one virtue of this interpretation is the ease with which it is able to account for his notoriously difficult thought-experiments and problem cases. In the final two chapters of this work I draw attention to virtues of this interpretation which are even more compelling. In Chapter Five I argue-in the process of responding to a series of objections-that a four-dimensional ontology fits best with Locke ' s theory of space his accounts of space and time, and that it also follows from the theory of creation which he received from Newton around the same time that he wrote his identity chapter. And in Chapter Six I show that a four-dimensional ontology also fits best with critique of essentiali sm, since his theory of identity is inconsistent with his anti-essentialism if he has a three-dimensional ontology , but not if he has a four-dimensional ontology.

5

OBJECTIONS AND REPLIES

In the previous chapter I argued that the organisms and persons in Locke's

ontology have both spatial and temporal extent, and hence both spatial and temporal parts. While I do not claim that Locke was fully aware of these four-dimensional implications, I suspect that he was aware of them at some level of his understanding. It is important to point out, however, that not much rides on this supposition. For on my interpretation, the organisms and persons in Locke's ontology have both spatial and temporal extent whether he is aware of this or not. Hence he is a four-dimensionalist, whether he is aware of this or not. In this chapter I shall continue to develop my four-dimensional interpretation of Locke's identity chapter by defending it against some potentially serious objections. In Part One I consider the objection that this interpretation is blatantly anachronistic, since the view which I have attributed to Locke presupposes a treatment of space and time which did not exist until the present century. In response to this objection, I contend that he could have consciously embraced the four-dimensional ontology which I have attributed to him, since he had all of the necessary concepts for a such an ontology. In addition , I contend that his isomorphic treatments of space and time offers further evidence that he is genuinely attracted to such an ontology. I begin Part Two by showing that the atoms which compose Lockean organisms must also have both spatial and temporal extent. I subsequently consider the objection that his commitment to the corpuscularian hypothesis would have led him to reject this account of bodies . In response to this objection, I argue that his affirmation of Newton's theory of creation shows that he was more than willing to reject this hypothesis. For he was fully aware of the fact that this creation theory is incompatible with the received, corpuscularian account of bodies. I subsequently argue that in Locke's hands at least, this creation theory provides us with another reason for thinking that the bodies in his ontology have both spatial and temporal extent. For if God created mobile bodies in the way that Locke and Newton have suggested, these bodies would have to be divinely modified regions of space-time. 147 C. H. Conn (ed.), Locke On Essence and Identity © Kluwer Academic Publishers 2004

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I. THE CHARGE OF ANACHRONISM

In the previous chapter I argued that the organisms and persons in Locke's ontology have spatial and temporal extent. As with logical implications generally, if this one holds, then it holds whether he was aware of it or not. Nevertheless, if my interpretation is correct, and the passages in §§ 13, 16,17,23, and 25 point in the direction that I have suggested, then it would be pretty odd if he wasn't aware of the implication that persons might be temporally extended. I would even be willing to grant that if he couldn 't have entertained this possibility, then my reading of these passages is probably untenable. And so perhaps the most obvious objection to my fourdimensional interpretation of Locke's identity chapter is that it is blatantly anachronistic. For one might plausibly suppose that this view of objects presupposes or in some sense depends upon the four-dimensional geometries developed (e.g., by Minkowski) in response to Einstein's Theory of Special Relativity. Thus one might argue that Locke could not even have entertained such a view, much less have consciously developed and endorsed it. 1. Initial response I suspect that the plausibility of this objection stems from the fact that many philosophical defenses of four-dimensionalism rely heavily upon the concept of space-time, a concept which is clearly borrowed from 20th century physics. Thus, for example, Quine writes that we can think of a physical object "as simply the whole four-dimensional material content, however sporadic and heterogeneous, of some portion of space-time" (1970, 30). Similarly, Heller writes that "a physical object is the material content of a region of spacetime" (1990, 4). While many advocates of four-dimensionalism make use of the notion of space-time, I know of no philosophical defense of this view which depends upon premises drawn from scientific accounts of the physical universe. Rather, this view is typically grounded in purely philosophical concerns. Thus, for example, David Lewis (1986, 203f) argues that fourdimensionalism offers the only acceptable solution to what he calls the problem of temporary intrinsics, i.e., the problem of how it is possible for objects to have different intrinsic properties (such as color or shape) at different times. Richard Cartwright (1987) defends four-dimensionalism on the grounds that it enables us to affirm the existence of bodies which can both (i) gain and lose parts, and (ii) become scattered and unscattered .' In a similar vein, Heller (1990, 3) argues that endorsing four-dimensionalism I

For a summary of Cartwright's argument , see Paulo Dau (1986 , 471t).

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over three-dimensionalism saves us from being committed to at least one of the following "unpleasant" alternatives: (a) there is no such physical object as my body, (b) no physical object completely occupies the space which we would typically say is now exactly occupied by all of me other than my left hand, (c) no physical object can undergo a loss of parts, (d) there can be distinct physical objects exactly occupying the same space at the same time, (e) identity is not transitive. I suspect that most of us will agree with Heller's disparaging assessment of these alternatives: other things being equal , we would like to deny each of them. But, Heller argues, we cannot consistently do so unless we reject three-dimensionalism in favor of four-dimensionalism.' According to David Oderberg, Quine comes the closest to making an explicit connection "between the contemporary physical conception of space-time and temporal-part theory" (1993, 107). For, Quine suggests, treating time "on a par" with space (in accordance with the natural sciences) provides us with a solution to Heraclitus's worry about not being able to step into the same river twice. Thus Quine writes that "once we put the temporal extent of the river on a par with the spatial extent, we see no more difficulty in stepping into the same river at two times than in two places" (1960, 171). Quine goes on to suggest that this treatment of space and time also helps to solve some of the perplexities of personal identity: The space-time view helps one appreciate that there is no reason why my first and fifth decades should not, like my head and feet, count as parts of the same man, however dissimilar. There need be no unchanging kernel to constitute me the same man in both decades, any more than there need be some peculiarly Quinian textural quality common to the protoplasm of my head and feet; though both are possible. (171)

Quine does not elaborate upon this "alignment of time with space ," except to say that it is "no novelty to natural science". Nor does he say what is involved in treating the temporal extent of a river "on a par" with its spatial extent. I suspect that this alignment of time with space involves thinking of things as having a temporal dimension in addition to having three spatial dimensions. In particular, it involves thinking of these 2 Heller points out that three-dimensionalists respond to this contradiction in various ways. Thus, for example, van Inwagen (1981) avoids this contradiction by accepting (b), Chisholm (I973) avoids it by accepting (c), Judith Jarvis Thomson (1983) avoids it by accepting (d), and Geach (I 967) avoids it by accepting (e).

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dimensions being strongly analogous to one another, so that many of the things which are said about an object's spatial extent can also be said about it temporal extent (e.g., that this object has both spatial and temporal parts) . This, I take it, is what it is to treat an object's temporal extent as "on a par" with its spatial extent. I contend, therefore, that Quine stops far short of grounding four-dimensionalism in the natural sciences. For he does not suggest that we should adopt this view of space and time because modem physics tells us to, he only says that this paraIIel treatment of space and time is no novelty to modem physics. 2. Some historical counterexamples to the charge ofanachronism

While it has not been previously suggested that Locke's ontology is populated by four-dimensional objects, several philosophers have attributed such an ontology to Hume, and not without reason. For in the Treatise Hume writes that "our chief business, then, must be to prove, that all objects, to which we ascribe identity, without observing their invariableness and uninterruptedness, are such as consist of a succession of related objects" (Liv.6: 255). Moreover, on at least three occasions in this context he refers to these successive objects as parts. Earlier in the same paragraph, for example, he writes that "the objects, which are variable or interrupted, and yet are suppos'd to continue the same, are such only as consist of a succession of parts, connected together by resemblance, continuity, or causation". Similarly, in the previous paragraph he writes that "our propensity to confound identity with relation is so great, that we are apt to imagine something unknown and mysterious, connecting the parts, beside their relation; and this I take to be the case with regard to the identity which we ascribe to plants and vegetable." According to H. H. Price, Hume is committed to temporally extended objects by his empiricist theory of ideas: Hume's whole theory of knowledge--the fact that he starts from impressions and will admit no 'idea' which is not derivable from them-e-commits him to what is called the Event-Theory of continuance ; according to which the continued existence of any entity whatever is equivalent to the occurrence of a series of numerically different particulars, whether qualitatively similar to each other or qualitatively dissimilar . (1940,47)

I suspect that Price is mistaken in thinking that Hume's theory of impressions and ideas alone commits him to the view that objects-like events-persist by having temporal parts, but the point remains that Price does claim to find this doctrine in Hume.

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More recently, Oderberg has also claimed to find this doctrine in the Treatise. Indeed , Oderberg contend s that Hume is the first philosopher to fully adopt an ontology of stages, and it is for this reason that he refers to the thesis that objects persist by perduring as the Humean view of identity (1993,61). Later he briefly attempts to justify this appellation: Suffice it to say that if we couple remarks of Hume' s, such as that identity is a matter of the 's uccession of parts, connected together by resemblance, contiguity or causation', or of the 's uccession of related objects,' with the fact that he is not always obviously referring to sense data, and indeed seems to slide from talk of the momentary manifestations of objects to the manifestations of momentary objects, we have a strong case for regarding Hume as the father of reductionism in the theory of diachronic identity. (64)

Although some passages suggest otherwise, I contend that Hume does not think that physical objects persist by being temporally extended, since he does not think that they persist. Although he refers to these successively related objects as parts, he evidently does not think that they are parts of anything, for he does not think that they are ever united into a single thing. Indeed, he writes that it is a "confu sion and a mistake" to suppose that we are dealing with a single continuant, when we are really dealing with a series of numerically distinct, successively existing objects (254). He even goes on to offer a psychological explanation for this mistake , suggesting that the qualitative similarity between successive objects "facilitates the transition of the mind from one object to another, and renders its passage as smooth as if it contemplated one continu'd object". Why does he refer to these successively related objects as parts, if he does not think that they are parts? Perhaps he refers to these objects as parts largely because he reads Locke in this way, and because his treatment of identity is a direct response to Locke's. More generally , he may be referring to these objects as parts because they would be parts, if they all belonged to a single, persisting thing (as we are falsely disposed to think) . That this, he calls them parts because they are the supposed parts of the supposedly continuing objects whose nature we are investigating. Although Hume does not think that objects persist by being temporally extended, it is appropriate to say that he has object-stages in his ontology. For what are these momentarily existing cat-like objects, if not cat-stages? Only we must keep in mind that for Hume, no two cat-stages are stages of a single, persisting cat. In other words, Hume does not think that numerically distinct, successively existing object-stages are ever diachronically compounded into a single, temporally extended thing. Hume 's organisms are what Chisholm calls entia successiva: what we (strictly speaking) erroneously treat as a single cat is really a series or succession of

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qualitatively similar, numerically distinct, and momentarily existing cat-like objects (Chisholm 1976, 101-3).3 Like Hume, the American philosopher Jonathan Edwards-a contemporary of Hume's and a keen student of Locke's Essay-has the concept of an object-stage. But unlike Hume, he also thinks that successive, momentarily existing object-stages can be united into a single object. As it has occasionally been pointed out, Edwards's doctrine of temporal parts arises out of his defense of the doctrine of original sin, whereby the guilt of Adam's first act of rebellion is imputed to his posterity." According to Edwards, in order to understand this doctrine we must bear in mind that "God, in each step of his proceedings with Adam, in relation to the covenant or constitution established with him, looked upon his posterity as being one with him" (389).5 In other words, we share in Adam's guilt because God has united us to him, "something as the branches of a tree are united to the root, or the members of a body to the head; so as to constitute as it were one complex person, or one moral whole" (391n). In particular, Edwards's theory of temporal parts arises out of his defense of this doctrine against the objection that God's treating Adam and his posterity as one "is altogether improper, as it implies falsehood; viewing and treating those as one, which indeed are not one, but entirely distinct" (397). Edwards contends that the apparent force of this objection "arises from ignorance or inconsideration of the degree, in which created identity or oneness with past existence, in general, depends upon the sovereign constitution and law of the Supreme Author and Disposer of the universe" (397). By "created identity or oneness" Edwards means the relation which a created substance bears to itself at different times. Like Descartes and Malebranche, Edwards endorses a version of the traditional, Scholastic doctrine that there is no real difference between God's creating the universe and his keeping it in existence." Thus Edwards: According to Chisholm (1979) and Shoemaker (1979), Thomas Reid and Bishop Butler also maintain this view of organisms. But unlike Hume, they do not think that persons are entia successiva. For Reid's views on these matters, see the third and sixth essays of his Essays on the Intellectual Powers of Man (found in Perry (1975» . For Butler's, see his "Of Personal Identity," which is the first appendix of his Analo gy of Religion (1736), and which is also found in Perry (1975). 4 See, for example, Roderick Chisholm (1971, 11-13) and (1976, 138-40); and Mark Heller (J 990,21-23). 5 All quotations of Edwards are taken from The Great Christian Doctrine of Original Sin Defended , vol. 3 of The Works ofJonathan Edwards , edited by John E. Smith. 6 Descartes defends this doctrine, e.g., in part 5 of his Discourse on Method (CSM 1:33; AT VII:45); in his Principles of Philosophy at 1.21 (CSM 1:200; AT IXB:13) and at 11.42 (CSM I: 243; AT VIIIA:66); in the Third Meditation (CSM II:33; AT VII:49); and in the First Set of Replies (CSM II:79; AT VII:I 10). For Malebranche 's defense of this doctrine, see his Dialogues on Metaphysics VII.7-12. 3

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The existence of each created person and thing, at each moment of it, [is] from the immediate continued creation of God...God's preserving created things in being is perfectly equivalent to a continued creation, or to his creating those things out of nothing at each moment of their existence. (401) God's upholding created substance, or causing its existence in each successive moment, is altogether equivalent to an immediate production out of nothing, at each moment, because its existence at this moment is not merely in part from God, but wholly from him; and not in any part, or degree, from its antecedent existence. (402)

Edwards subsequently contends that this doctrine of creation implies that each, successive effect of God's creative activity is a numerically distinct object: If the existence of created substance, in each successive moment, be wholly the effect of God's immediate power, in that moment, without any dependence on prior existence, as much as the first creation out of nothing, then what exists at this moment, by this power, is a new effect; and simply and absolutely considered , not the same with any past existence, though it be like it, and follows it according to a certain established method. (402)

Thus far, Edwards's position seems very much like Hume's. For like Hume, Edwards contends that what we commonly think of as a single, enduring cat is really a succession of qualitatively similar cat-stages. But unlike Hume, Edwards thinks that distinct cat-stages can be stages of the same cat. For he contends that God can will that a series of object-stages be the stages of a single object. Thus he writes that in the case of created substances, there is no diachronic identity "but what depends upon the arbitrary? constitution of the Creator; who by his wise sovereign establishment so unites these successive new effects, that he treats them as one, by communicating to them like properties, relations, and circumstances; and so, leads us to regard and treat them as one" (403) . In saying that God treats distinct objects as one, Edwards might seem to be depicting God as feigning identity in the same way that Hume thinks we do. But he doesn't say merely that God acts as though these stages have been united into a single thing. Rather, he thinks that God brings it about that successive objects are united into a single thing. "In affairs of this nature," he writes, "a divine constitution is the thing which makes truth ." 7 "When I call this an arbitrary constitution," Edwards explains, "I mean, that it is a constitution which depends on nothing but the divine will; which divine will depends upon nothing but the divine wisdom" (403).

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(404). It is important to note, moreover, that he does not think that this divine convention unites successive objects by making them identical with one another, for he clearly takes this to be an impossibility . Rather, he thinks that God unites these objects by making them part-identical, i.e., by making them different parts of a single object. For reasons which we have already considered, the aggregate of these parts would have to be a temporally extended object. For such an object could not possibly exist in its entirety at anyone moment of time. It is not hard to see how this divinely constituted, diachronic unity provides Edwards with a response to the charge that the doctrine of original sin commits God to falsely saying that distinct objects are one. As John E. Smith nicely puts it, "according to Edwards, what takes place with respect to each individual also takes place with respect to all individuals considered as a species" (1992, 97). That is, just as God can bring it about that a series of distinct cat-stages are united into a single, perduring cat, he can also bring it about that Adam and his posterity are also united into a single, complex person. Thus Edwards concludes: I am persuaded [that] no solid reason can be given, why God, who constitutes all other created union or oneness, according to his pleasure...may not establish a constitution whereby the natural posterity of Adam...should be treated as one with him, for the derivation, either of righteousness and communion in rewards, or of the loss of righteousness and consequently corruption and guilt. (405)

Given that Edwards thinks that a single, persisting object is diachronically compounded out of successive, momentarily existing objects, it is clear that Edwards is committed to what I have been calling fourdimensional objects, i.e., objects which have both spatial and temporal extent, and hence both spatial and temporal parts. This fact, moreover, seriously undermines the objection that my four-dimensional interpretation of Locke is an anachronism. For if Edwards is capable of entertaining this view of objects in the absence of four-dimensional, relativistic geometries, then there is no reason why Locke could not also have done so. Before we turn to Locke's theory of bodies-in connection with the corpuscularian hypothesis and Newton's theory of creaton-I would like to briefly discuss Locke isomorphic treatment of space and time. For this provides us with yet another reason for thinking that he is (at some level) attracted to the thesis that objects have both spatial and temporal extent.

OBJECTIONS AND REPLIES

ISS

3. Locke's views on space and time

Since four-dimensionalists maintain that objects are extended in time in a way that is analogous to their being extended in space, it is no accident that they tend to draw strong analogies between space and time. Thus, for example, Heller writes that "insofar as time is just one more dimension, roughly alike in kind to the three spatial dimensions, we should expect that our claims about an object' s spatial characteristics have analogues with respect to its temporal characteristics" (1990, 5). He subsequently mentions three such analogues between a thing's spatial and temporal characteristics. First, he observes that we can speak both of the distance between two points in space, and of the distance between two points in time. This, in tum, "allows us to understand the notion of temporal boundaries as analogous to that of spatial boundaries." Second, he suggests that an object's spatial and temporal characteristics are also analogous with respect to the part/whole relationship, for just as a (proper) spatial part of an object occupies a subregion of the space which is occupied by the whole object, so a (proper) temporal part of an object occupies a subregion of the time which is occupied by the whole. Finally, Heller points out that "for both spatial and temporal parts, we can point at or perceive or name a whole by pointing at, perceiving or indicating a part." That is, just as we can refer to a spatially extended object by referring to one of its spatial parts, we can similarly refer to a temporally extended object by referring to one of its temporal parts. McTaggart's four-dimensionalism is clearly grounded in analogies like those mentioned above by Heller. According to McTaggart, the conception of a dimension is applicable to "wherever a series may be found" (1921, 174). Thus, he argues that this concept is not only applicable to space, but also to time. This, in tum, leads him to conclude that whatever exists in time has a temporal dimension, just as whatever exists in space has at least one spatial dimension. Accordingly, he contends that whatever exists in both space and time has both spatial and temporal dimensions, writing that "if what is three-dimensional in space is also in time, then it has time as a fourth dimension" (174). His four-dimensionalism is nicely summed up in the following passage: As we have seen, time is a dimension of whatever exists in time. And everything which exists through several parts of time will have, as its own parts, itself as existing in each of those parts of time. "St Paul's Cathedral in the nineteenth century," and "St Paul's Cathedral in 1801," are both names of substances. But they are the names of different substances , since many assertions are true of St Paul's in the nineteenth century which are not true in St Paul's in 1801, and vice versa. And the second substance is part of the first. If we take the substances which are named "St Paul's in 1801," "St Paul's in 1802,"

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CHAPTER FIVE and so on to "St Paul's in 1900," they will together include all the content which is included in "St Paul's in the nineteenth century." (176)

Like Quine, McTaggart clearly thinks that whatever exists in both space and time has both spatial and temporal dimensions, and hence both spatial and temporal parts. It is important to point out, moreover, that McTaggart's "alignment of time with space" is not based upon the four-dimensional, space-time geometries developed in response to relativity theory. Rather, it is based solely upon his concept of a dimension, a concept which he borrows from §354 of Russell's Principles of Mathematics (1903), which was written several years before the onset of relativity theory. Whereas advocates of four-dimensionalism tend to emphasize the analogies between space and time, the opponents of this view tend to emphasize the obvious disanalogies. Thus, for example, Chisholm argues that we should reject four-dimensionalism, since there is a "fundamental disanalogy between space and time," to wit, that "one and the same thing cannot be in two different places at one and the same time. But one and the same thing can be at two different times in one and the same place" (1976, 140).8 Although Chisholm suggests otherwise, I see no reason for thinking that the truth of four-dimensionalism rests upon the thesis that a thing's spatial characteristics are completely analogous to its temporal characteristics . Heller himself admits that time and space are not completely alike, since time seems to have a direction to it, since our perception along the temporal dimension is one-directional and discontinuous, and since temporal units of measurement differ in kind from spatial units of measurement (1990, 6). Indeed, his defense of fourdimensionalism depends upon the first of these disanalogies, for he argues that the direction of time is needed to explain how it is possible for fourdimensional objects to change (1992, 702-4). I do not think that one's position in the debate over whether physical objects have zero or non-zero temporal extent is solely a function of one's attitudes towards these analogies and disanalogies. But it does seem fair to say that those who find these analogies to be strong and philosophically important are likely to be attracted to the view that objects are extended in time in a way that is analogous to their being extended in space. It also seems fair to say that those who are more impressed by the disanalogies between space and time are likely to reject this view. Having said this, the Richard Taylor (1955, 601) points out that this statement fails to identity a simple and obvious difference between space and time. For just as an object can be in a single place at more than one time if it lasts long enough, an object can be in more than one place at a single time if it is large enough .

8

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next question is obvious: where does Locke stand on this matter? That is, what is his position, if any, on the relative strength and importance of these analogies and disanalogies? It is no understatement to say that Locke was greatly impressed by the similarities between space and time. Indeed , he devotes an entire chapter of the Essay to it, a chapter entitled "of Duration and Expansion, Considered Together" (II.xv). While it is not within the scope of this work to examine Locke 's treatment of space and time in detail, I would like to discuss one aspect of this treatment, namely, his use of predominantly spatial concepts--such as distance, length, and extent-in connection with the temporal dimension of things. Locke's most prolonged discussion of time occurs in II.xiv of the Essay, immediately after his discussion of space in II.xiii. In II.xiv he introduces the notion of duration as "another sort of Distance, or Length," a notion, he observes, which comes from "the fleeting and perpetually perishing parts of Succession" (§1). He concludes the first section of II.xv by noting that in both duration and expansion "the mind has this common Idea of continued lengths, capable of great, or less quantities." He subsequently likens both space and time to oceans which are similarly boundless and uniform. Thus in §5 he refers to the "boundless Oceans of Eternity and Immensity," as "those uniform infinite Oceans of Duration and Space". And in §8 he writes that "the boundless invariable Oceans of Duration and Expansion; which comprehend in them all finite Beings, and in their full Extent, belong only to the Deity" (emphasis added). The fact that he likens both time and space to an infinitely extended ocean suggests that he is comfortable with thinking of time as space-like. This observation is further supported by the fact that frequently speaks of spaces, lengths, and distances of time or duration. Thus, for example, he uses the phrase "length(s) of duration" on nine occasions in Book II. 9 On two other occasions he uses the phrase "space(s) of duration" (xiv. 19; and xv.8). At xiv.19 he uses the phrases "distances of duration"; he uses the phrase "distance of time" on two occasion in the Essay (II. xi v.19; and II.xxvii.lO), and on two occasions in the Two Treatises of Government (Lxi.113). Not only does he depict both space and time as having an extent in II.xv.8, he writes that their extent comprehends (= contains) all finite objects . And though he denies that God is comprehended by space or time, in xv.3 he speaks of God as (completely) filling both space and time, with the suggestion being that created objects fill or occupy lesser portions of space and time. He makes this suggestion even more clearly towards the end of xv.8. The passage begins as follows: 9

See xiv.21, 23, 27, 31; xv.3; xvii.5; xxvi.4; and xxix.5.

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CHAPTER FIVE When applied to any particular finite Beings, the Extension of any Body is so much of that infinite Space, as the bulk of that Body takes up. And Place is the Position of any Body, when considered at a certain distance from some other. As the Idea of the particular Duration of any thing, is an Idea of that Portion of infinite Duration, which passes during the Existence of that thing.

Locke seems to be working with an analogy between an object's spatial extension and its duration , and hence between an object's spatial and temporal characteristics. The first set of characteristics is concerned with a "portion" of infinite space, and the second set is concerned with a portion of infinite duration. At present, however, the analogy is not a particularly strong one. For his treatment of a body's spatial characteristics is not completely isomorphic with his treatment of its temporal characteristics . The first set concerns the portion (of space) which the body takes up, while the second set concerns a portion (of duration) which passes "during the existence of that thing". In the remainder of this passage, however, the analogy becomes much stronger: ...the time when the thing existed, is the Idea of that Space of Duration, which passed between some known and fixed Period of Duration, and the Being of that thing. One shews the distance of the Extremities of the Bulk, or Existence of the same thing, as that it is a Foot Square, or lasted two Years; the other shews the distance of it in Place, or Existence from other fixed points of Space or Duration; as that it was in the middle of Lincoln s-Inn-Fields , or the first degree of Taurus, and in the year of our Lord, 1671 or the 1000 year of the Julian Period. (II.xv.8)

His treatment of an object's spatial characteristics is now thoroughly isomorphic with his treatment of its temporal characteristics. His use of the phrase "space of duration", for example, suggests that he takes persisting objects to "fill" time in a manner which is analogous to their filling space. Note, moreover, his contention that "one shows the distance of the Extremities of the Bulk, or Existence of the same thing...the other shews the distance of it in Place, or Existence." Here Locke is clearly working with an analogy between an object's spatial and temporal boundaries, and with an analogy between an object's spatial and temporal location . The expressions "the one" and "the other" are being used to contrast an object's extent with an object's place. What's more, when he describes the extent of an object, as when he describes its place , he includes both its spatial and its temporal characteristics . Locke's analogous treatment of space and time, and in particular his analogous treatment of an object's spatial and temporal boundaries, show

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that he has a strong--if subliminal--motive for taking objects to have both spatial and temporal extent, and hence both spatial and temporal parts. Nor do I think that he would object to this use of 'part' . Indeed, a passage in the second draft of the Essa y strongly suggests that he has the concept of a temporal part. Thus in §127 of Draft B he writes: Our Ideas of Duration & Space doe include in them an aggregation of parts the one conceived coexistent, the other in succession, & both measurable or recond by number, & noe other Ideas but these doe originaly include parts in them, but whatsoever is conceived to have parts is either on the account of extension or duration. (250)

I take it that the scope of "whatsoever" not only includes both time and space, but also things which exist or occur in time and space, like baseballs and baseball games. This, in turn, leads me to conclude that Locke has the notion of a temporal part. For he suggests that something can be conceived to have parts simply in virtue of the fact that it exists for a period of time. Clearly, these would have to be temporal parts. And while this does not support the conclusion that he thinks anything has temporal parts, it is nonetheless significant that he can at least conceive of something's having temporal parts. The above passage is significant for another reason. The fact that he speaks of both types of parts as forming aggregates shows that he recognizes both synchronic and diachronic compounds, i.e., compounds whose parts exist at the same time, and compounds whose parts exist in succession. While the above considerations all focus on the relationship which an object has both to space and time, Locke briefly discusses the relationship which these dimensions have to one another. In the summation of "of Duration and Expansion, considered together" he writes: To conclude, Expansion and Duration do mutually imbrace, and comprehend each other; every part of Space, being in every part of Duration, and every part of Duration, in every part of Expansion. (Ilxv.l2)

After drawing attention to this passage, John Yolton queries whether Locke has a concept of space-time (1993, 299). In light of Howard Stein's comments on a similar statement by Newton, I am inclined to think that this query must answered in the affirmative. In the General Scholium of his Principia Newton writes:

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CHAPTER FIVE Since every part icle of space is alway s, and every ind ivisible moment of duration is everywhere, certainly the Maker and Lord of all things canno t be never and nowhere."

It is pretty clear that these passages are equivalent. For to say, as Locke

does, that every part of space is in every part of time, is to say, with Newton, that every part of space is always. Similarly, to say, as Locke does, that every part of time is in every part is space, is to say, with Newton, that each part of time is everywhere. Stein contends that the conjunction of these statements involves a concept of space-time. For, he writes, to say that every par ticle of space is alwa ys and every moment of duration is every where is exactly to identify the "particles of space" or points with certain one-dimensional submanifolds of space-time, and the "moments of dur ation " or instants with certain thre edimensional slices or submanifolds. (1977, 13)

In order to show that this interpretation is no mere anachronism, Stein cites a passage from Kant' s inaugural dissertation which indicates that he also read Newton in this way. In the middle of a footnote to § 14 of his On the Forms and Principles of the Sensible and Intelligible World, Kant writes: Th ough time has only one dimension, yet the ubiquity of tim e (to spea k with Newton)...adds a further dim ension to the magn itud e of actual things...For if you were to represent time by a straight line extended to infinity, and simultaneo us things at any point of time by lines drawn perpendicular to it, the surface thu s generated would represent the ph enomenaL worLd in respect both of substance and of acci dents . I I

Although I am hardly qualified to comment upon Stein' s observations, I do find them to be convincing. Thus, I suspect that the above passages from Locke and Newton do commit them to some sort of space-time continuum. Indeed, it appears that Locke is consciously aware of this implication, given his observation that space and time "do mutually imbrace, and comprehend each other".

10 Quoted from the translation by Andrew Motte and Florian Cajori. It is worth pointing out that the this passage was not present in the first edition of the Principia, which was the only edition that Locke ever saw, since the second was published in 1713, nearly a decade after Locke' s death. 11 Quoted from Theoretical Philosophy: 1555-1770, vol. I of The Cambridge Edition of the Works of Immanuel Kant (1992), p. 394.

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II. FOUR-DIMENSIONAL BODIES AND THE CORPUSCULARIAN HYPOTHESIS

1. The temporal extent of Lockean atoms and masses

In Part One of Chapter Four I argued that Locke's treatment of persistence for both atoms and masses is neutral with respect to the question of dimensionality. Although none of his statements on atoms and masses suggest that he attributes temporal extent to these objects, neither do they suggest otherwise. I subsequently argued that atoms and masses must have the same dimensionality, i.e., that masses of atoms have temporal extent if and only if atoms have temporal extent. In Part Two I argued that Lockean organisms are diachronically compounded out of successively existing, numerically distinct masses of matter, which implies that Lockean organisms are the four-dimensional sums of their temporal parts. Here I would like to develop one additional implication of this position: if organisms are temporally extended objects, then so are atoms and masses. Let us suppose, with Locke, that Tabby is a diachronic compound. That is, Tabby is (diachronically) compounded out of successively existing, numerically distinct masses of matter. Given the various physiological processes which are involved in sustaining the life of a cat (e.g., respiration, digestion), we know that these masses don't last for long, although some of them might last longer than others. It all depends upon the rate at which old atoms are being cast off and new atoms are being taken in. Thus, for example, the constituent masses of an organism which happens to be in a highly active metabolic state (e.g., a feeding hummingbird) would exist for a very short period of time, whereas the constituent masses of an organism in a state of torpidity (e.g., a sleeping hummingbird) would last for a relatively long time. Let 'm' stand for one of Tabby's more "durable" constituent masses, and let us suppose that m exists for exactly three seconds, say, from to to t3' Now let 'p ' stand for the temporal part of Tabby which exists from to to t3. Since there is no temporal part which cannot subdivided into even briefer temporal parts, we can divide P into parts which exist for exactly one second. Thus, during the existence of m, Tabby is composed of three numerically distinct temporal parts, one which exists from to to tl, one which exists from tl to t2, and one which exists from t2 to t3. Let 'PI' stand for the first of these temporal parts, and let 'P2' and 'P3' stand for PI'S successors. Since each of these temporal parts is a spatially extended object, their mereological sum must itself be a spatially extended object, one, moreover, which exists from exactly to to t3' Since m is also a spatially extended object which exists from to to ts- I think that Locke has no choice but to say that m

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is the mereological sum of PI, P2, and P3' But since each of these parts is also a temporally extended object, their mereological sum must itself be a temporally extended object, which further entails that m is temporally extended. To put this point another way, since m is composed of three successively existing, numerically distinct physical objects, m cannot be a threedimensional object which exists-s-in its entirety--at every moment of its existence. For in that case, the object which exists from to to tl would be identical with the object which exists from ti to t3, but these objects are clearly not identical with one another . Hence, m must be a four-dimensional object, the sum of its temporal parts. Given that m has both spatial and temporal extent, I think Locke is committed to saying that all of Tabby's constituent masses have both spatial and temporal extent, and indeed to saying that this result holds for masses of atoms generally. And since masses of atoms have temporal extent if and only if atoms have temporal extent, he is committed to attributing temporal extent to atoms as well. Now even though Locke's treatment of persistence in the case of atoms appears to be neutral with respect to the debate over temporal extent,12 it is reasonable to suppose that he did not take atoms to have temporal extent, and that he would have unhappy with this implication. For temporally extended atoms do not strike us as being very atomistic-they seem to be more like worms than corpuscles. Indeed, it is reasonable to suppose that he would have rejected the view that organisms have temporal extent in order to avoid this commitment. Hence on this view, the position which I have attributed to Locke is both inherently unstable and ultimately unlockean: it is unstable because he would be unwilling to accept some of its obvious implications, and it is unlockean because these implications are at odds with his corpuscularianism. I am willing to grant both that Locke did not take atoms to be temporally extended, and that he would have been at least initially unhappy with this implication. But I deny that Locke would have rejected his account of persistence for organisms and persons in order to avoid this commitment. For, I shall argue, a four-dimensional account of bodies also follows from the theory of creation which he received from Newton, and he was surely aware that this theory is itself incompatible with the corpuscularian hypothesis.

12 See

above , pp. loo£.

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2. Locke and Newton on the creation ofmaterial corpuscles

In IV.x.18 Locke discusses the creation of both spiritual and corporeal substances, and he contends that God creates both sorts of substances out of nothing. In the version of this passage which is present in the first edition of the Essay, he claims that God's manner of creating both sorts of substances is "equally beyond our comprehension". The creation of bodies, he contends, is just as incomprehensible as the creation of spirits. Significantly, he retracts this contention in the second edition of the Essay, and suggests that the creation of bodies is comprehensible, after all. Thus Locke: If we would emancipate our selves from vulgar Notions, and raise our Thoughts, as far as they would reach, to a closer contemplation of things, we might be able to aim at some dim and seeming conception of how Matter might at first be made, and begin to exist by the power of that eternal first being: But to give beginning and being to a Spirit, would be found a more inconceivable effect of omnipotent Power. (IV.x.l8)

Locke does not elaborate upon this "dim and seeming conception," ostensibly because doing so "would perhaps lead us too far from the Notions, on which the Philosophy now in the World is built." Leibniz is clearly frustrated by the incompleteness of Locke's account, blaming it on his "over-scrupulous caution". Speaking through Theophilus, he writes that Locke has "brought us to a certain point with our mouths watering, [and] left us standing there" (New Essays IV.x.18). Leibniz was convinced that "there is something fine and important hidden under this rather enigmatic passage" (IV.x.18). Since he had thus far been unable to draw Locke into direct correspondence, on October 7, 1704 he wrote the following in a letter to Damaris Masham, a close personal friend of Locke's: I noticed in Mr. Locke's Essay, book 4 chapter 10, a thought which appears important, which he seems to have been unwilling to reveal to the uninitiated but which ought not to be allowed to slip through our fingers since this remarkable man is still with us. It concerns the way of conceiving how matter has been made, and how it is more difficult to make spirits. Which does appear important in getting to the root of things. Your credit with him makes me hope that we can draw on it to obtain some light through your mediation . I would be delighted if the light could spread as far as me."

13 Quoted from and translated by Bennett and Remnant (1978, 3). For the untranslated version of this letter, and for Lady Masham's response, see C. I. Gerhardt's edition of

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Unfortunately, Leibniz was not able to gain access to Locke through Lady Masham, for she received his letter some two days after Locke's death, and she could not recall having had any discussions with Locke on this topic. Pierre Coste--an intimate acquaintance of Locke's and the French translator of the Essay--was also asked to shed light upon this enigmatic passage. Thus in the second edition of his translation of the Essay Coste adds the following note to Locke's enigmatic passage : Here Mr. Locke arouses our curiosity but is unwilling to satisfy it. Within a short time after my translation appeared, many people asked me to divulge it to them; but I had to confess to them that Mr. Locke had kept it a secret even from me. Eventually, long after his death, the whole mystery was unveiled for me by Sir Isaac Newton, to whom I happened to mention this part of Mr. Locke's book. Smiling, he told me first that it was he himself who had devised this way of explaining the creation of matter, the thought of it having come to him one day when he happened to touch on this question in company with Mr. Locke and an English lord....Here is how he expounded his thought to them. One could (he said) in some fashion form an idea of the creation of matter by supposing that God could through his power prevent everything from entering a certain portion of pure space, space being by its nature penetrable, eternal, necessary, infinite; for thereafter that portion of space would possess impenetrability, which is one of the essential qualities of matter. And as pure space is absolutely uniform, we have only to suppose God to have communicated this kind of impenetrability to another similar portion of space, and that would give us some sort of idea of the mobility of matter, another quality which is also utterly essential to it. So now we are freed from the search for what Locke had thought fit to hide from his readers."

Thanks to Coste's testimony, we can now explain Locke's emendation to the second edition of the Essay, in which he claimed to have a "dim and seeming conception of how matter might at first be made" . This dim and seeming conception is evidently the mechanism suggested to him by Newton, according to which God creates material bodies by conferring the property of impenetrability upon particular regions of space .

Leibniz's correspondence, Die Philosophischen Schriften von Gottfried Wilhelm Leibniz (Berlin, 1875-90), vol. 3, pp. 297f, and 364. 14 Quoted from and translated by Bennett and Remnant (1978, 5). For other discussions of Coste's encounter with Newton, see A. C. Fraser's critical edition of the Essay (1894, 32122n); Alexendre Koyre (1965, 91-93); Howard Stein (1970, 274-75); Martin Tamny (1979); Roger Woolhouse (1982); Thomas Lennon (1984); and Michael Ayers (1991,2:59, 304n.85).

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We get a much fuller-and probably much earlier-account of Newton's creation theory in his De gra vitatione et aequipondio fluidorum .P Bennett relays part of this account in his book on Spinoza's Ethics: God decides to add a mountain to the world, which he does by modifying a certain mountain-shaped and -sized region of space so that it affects everything else ju st as mountains do: other bodies cannot enter; if they reach the region quickly, sound is emitted and they are bent or shattered; light is reflected, and so on. If the job were done right, Newton says, we would have every reason to suppose that a mountain had been added to the furniture of the world; and he takes this to support his suggestion that actual physical things are just regions of space which have been suitably thickened, so to speak. (1984,89)

Like Bennett, I do not take Newton (or Locke) to be merely offering an account of how material bodies might have been made. Rather, I take him to be (cautiously) offering an account of how bodies were made. I likewise agree with Bennett's suggestion that Newton 's account of how bodies were made provides us with an account of what bodies are. Indeed, Newton is quite explicit about this: his account of creation is the first part of his attempt at "an explanation of the nature of body" (138, emphasis added). If God creates an atom by conferring the property of impenetrability upon an atom-sized and -shaped region of space, then it follows that an atom is a region of space. Thus, for example, Howard Stein writes: It is not metaphor, but a literal truth, that Newton's metaphysics of body reduces the notion of matter to the notion of a field. A body, Newton tells us, is a region of space endowed with certain properties . The clarity, or intelligibility , of the properties Newton specifies consists in the fact that they are conceived ideally as testable: they are dispositional characteristics of the spatial region, like the field quantifies of gravity or electro-magnetism. In particular, Newton takes as basic what is quite natural to call the "impenetrability field"-a two-valued function on space (or rather space-time), since impenetrability either is there or is not. (1970, 276t) .

Similarly, Arnold Koslow points out that in De gravitatione Newton takes a body to be nothing more than "a specially 'God-conditioned' part of space" (1976, 242). I shall henceforth refer to bodies which have been created in this way as Newtonian bodies. 15This fragment of Newton' s (henceforth cited as De Gravitatione) was first published (in Latin and English) and translated by Rupert HaIl and Marie Hall (1962). For discussions of the date of this work, see HaIl and Hall (1962, 89), Howard Stein (1970, 274n.ll), and Roger Woolhouse (1982, 88n.IO).

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At first glance , it looks as if Newton is forced to deny that bodies are regions of space. Speaking of these regions of impenetrability, which he says "will either be bodies or like bodies," Newton writes: If they are bodies, then we can define bodies as determined quantities of extension which omnipresent God endows with certain conditions. These conditions are, (1) that they be mobile; and therefore I did not say that they are numerical parts of space which are absolutely immobil e, but only definite quantiti es which may be transferred from space to space; (2) that two of this kind cannot coincide anywhere; that is, that they may be impenetrable, and hence that when their motion s cause them to meet they stop and are reflected in accord with certain laws; (3) that they can excite various perceptions of the sense and the fancy in created minds, and conversely be moved by them . (De gravitatione, 140)

On the assumption that these regions of impenetrability are bodies-and hence that they do not merely seem to be bodies-Newton proposes that they be defined as determined quantities of extension which are both mobile and impenetrable, and which are capable of interacting with other bodies (and minds) in a law-governed manner. Note, in particul ar, that Newton takes the mobility of these bodies to preclude them from being the "numerical parts of space", which he takes to be completely immobile. 16 Now it may look as if Newton is saying, in the same breath, both that bodies are (divinely modified) regions of space, and that bodies cannot possibly be region s of space, since bodies are mobile, while regions are essentially immobile. Although Newton may well be involving himself in a contradiction in this passage, I do not think that he is involving himself in this contradiction. It is more plausible to suppose that in denying that a body is a "numerical part of space", he is denying that a body is identical with some one part of space." For as his comments about the mobility suggest, he thinks that God can "move" a body from one region of space to another by transferrin g a determinate quantity of extension "hither and thither" or "from space to space" (139t). Thus, Stein explains, Having established a region of impenetrability, [God could]...confer the property of impenetrability, not on a fixed spatial region, but on differ ent regions at different times-and in such a way that the mutations of the distributi on of impenetrability constitute a smooth motion in space . ( 1970, 275)

16 It is important to note that Locke and Newton are complete agreement in this respect. Thu s, for example, Locke writes in II.xiii.l 3 that the regions of space are inseparable from one another, and in the following section he takes this to entail their immobility. 17 Here I follow Arnold Koslow (1976, 242).

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As Stein observes, a number of conditions must be satisfied if these successive instantiations of impenetrability are going to count as an instance of bodily motion. Some of these details are provided in a similar passage from Bennett and Remnant: What could it mean to say that a particular 'quantity of extension ' might be 'transferred from space to space' ? Perhaps at the back of his mind Newton has the following idea. If F is a property which some regions of space are suffused with, God might ensure that the total quantity of F-suffused space is constant, while allowing change in which regions have F. If those changes satisfied an appropriate continuity condition, the upshot would be a kind of mobility for Fvolumes-Leo for amounts or 'quantities' of F-suffusion-with no implication that parts of space can themselves move. (1978,9)

Since I am primarily interested in what this theory of creation does for Locke, I am not going to say much more about Newton's development of this theory in De gravitatione. Indeed, I think that it would be a mistake to expect Locke's development of this theory to closely follow this work. For Coste tells us that Locke received this theory from Newton in conversation, which suggests that he probably did not receive a detailed account of this theory. And even if Newton had been able to convey a fairly detailed account of this theory, we should not assume that it would have closely followed his development of this theory in De gravitatione. For it is widely agreed that this work was probably written some time in the 1660's, and that it was almost certainly written before 1672. Moreover, we know that this conversation between Locke and Newton could not have taken place until late in 1689. 18 In light of Coste's testimony, I think that we can safely assume, first, that he received the general account of how bodies are made, according to which God creates bodies by modifying regions of space. Second, we can also assume that their conversation touched upon what this theory says about the nature of bodies, to wit, that a body is a (divinely modified) region of space. And third, we can assume that this conversation touched upon something like the above explanation of mobility, according to which God "moves" bodies modifying a series of spatial regions in the appropriate way. In light of these assumptions, it is not hard to see why Locke thinks that an elucidation of this theory "would perhaps leads us too far from the Notions, on which the Philosophy now in the World is built." The passage confirms what should already have been fairly obvious, namely, that he quite rightly takes this theory of creation to involve a radical departure from the received 18 For a detailed account of the various possible dates of their acquaintance, see G. A. J. Rogers (1978, 2300.

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(=corpuscularian) account of bodies. Hence his endorsement of this theory indicates that he is willing to make such a departure , which undermines the previously mentioned contention that he would reject a four-dimensional account of atoms out of deference to his corpuscularianism. Indeed, I shall now argue that his endorsement of this theory provides an even stronger reason for thinking that he would be willing to endorse fourdimensionalism, since in Locke' s hands at least, this theory entails a fourdimensional account of material objects.

3. The temporal extent ofNewtonian bodies Let us consider a single atom a, and let us suppose that God created this atom in the way that Newton and Locke have speculated . Let us further suppose, with Locke and Newton, that a is capable of existing for an extended period of time, and that a is capable of existing in different places at different times. In particular, let us suppose that a exists from tl to tn, and that a is in (i.e., is adjectival upon) a different region of space at each successive moment of its existence, so that a is in rl at tJ, in rz at t2, in r3 at ts- and so on. (For the sake of simplicity, let us suppose that these regions of space do not overlap.) According to the theory which Locke and Newton both accept, this requires that God transfer a given volume of impenetrability from one region to the next at the appropriate time and in the appropriate way. This account of creation tells us, among other things, that each of these regions is a body at the specified time. For if a body is nothing more than a divinely modified region of space, then rl is a body at tl ' ri is a body at t2, r3 is a body at t3, and so on." Let 'aI' stand for the first of these bodies, let 'a2' stand for the second, let 'a 3' stand for the third, and so on. Now let us consider the relationship between a and the referents of 'aI " 'a2" and 'a3" We have stipulated that a is a persisting atom, but we have not assumed anything about the manner of a's persistence. But we can say this: either a persists by enduring through time in its entirety, or else a persists by perduring over time. For a either lacks temporal extent, or else a has 19 Martin Tamny has argued that these successively existing bodies cannot be spatiotemporally continuous with one another For, he writes, "no matter how quickly God managed these successive endowments and withdrawals [of impenetrability], they would still remain successive and thus denumerable, which means that these bodies would not have spatio-temporal continuity" (1979, 56). Tamny is mistaken. The denumerability of these successive manifestations of impenetrability has nothing to do with their spatio-temporal continuity, since it is clearly possible for successively existing objects to be spatiotemporally continuous with one another. For arguments to this effect, see Sydney Shoemaker (1979), and David Armstrong (1980).

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temporal extent. If a lacks temporal extent, then a persists by enduring. Conversely, if a has temporal extent, then a persists by perduring. If a endures through time in its entirety, then a entirely "occupies" each of the above regions, which entails that a is identical with a J, a2, and a3. If a is a temporally extended, perduring entity, then a partly "occupies" these regions, which entails that a j, az, and a3 are distinct, successively existing parts of a. Indeed, if a is temporally extended, then a is the mereological sum of aj, a2, a3...an' We are now in a position to see why a cannot be an enduring, threedimensional body. If a body is simply a divinely modified region of space, then different divinely modified regions of space must be different bodies. In other words, aj and a3 must be numerically distinct bodies, since al = rl, since a3 = r3 and since rl "# r3' This, in tum , entails that aj, az, and a3 cannot possibly be identical with a. Hence, a must be a temporally extended object, and aj, az, and a3 must all be parts of a. Since each of these bodies is a divinely modified region of space, and since a is the mereological sum of these modified regions of space, it follows that a is a divinely modified region of space-time. In order to clear up any remaining doubts about the non-identity of al and a3, let us consider a slightly different case. Suppose that rl and r3 are hoth bodies at tl ' Let 'aI' continue to stand for the first of these bodies, and let 'b,' stand for the second. Now we know that al cannot be identical with bi, and we know this because rl and r3 are distinct regions of space. The only real difference between these two cases pertains to when the bodies in question exist, and since regions of space are immobile, the passage of time is irrelevant to the conclusion. Therefore, al must be distinct from a3 for the very same reason that al is distinct from b-: The passage of time does explain one thing, however: it explains why we might want to treat these cases differently. In the second case, we can see that we are dealing with distinct entities. Not so in the first case. Indeed, in this case the passage of time allows for the appearance that al is a3, since it allows for the appearance that a is enduring through time, which in tum allows for the appearance that a is moving through space. The theory of creation which Locke and Newton espouse is incompatible with three-dimensional bodies which both persist and move. Since they would be unwilling to suppose (with Hume) that such bodies do not persist, and since they would be equally unwilling to suppose that such bodies persist without moving, it looks like they must conclude that these bodies have both spatial and temporal extent. Indeed, they must conclude that each

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4. The mobility oftemporally extended bodies

Locke and Newton think that bodies are mobile, i.e., that they are capable of existing in different places at different times. They also think the causal interactions between bodies are largely if not completely a function of their motion and consequent impact. Thus, I take it that they would reject any account of the physical world which entails that bodies are not mobile. At least at first glance , however, it looks like a four-dimensional account of bodies entails just this. That is, it looks like four-dimensional objects do not move. Thus, for example, Bennett writes that "the table, we say, was moved from the yard into the kitchen; but of a four-dimensional table we should rather say that one temporal part of it was in the yard and a subsequent part in the kitchen" (1988, 114). The force of Bennett's contention is nicely elucidated by the following argument. Suppose that baseballs are made of atoms, and that atoms have both spatial and temporal extent. This entails that baseballs have both spatial and temporal extent, and hence both spatial and temporal parts. Let 'b' stand for one such baseball. As a four-dimensional object, b persists by perduring. In other words, b exists at different times in virtue of its having different temporal parts at these times. Moreover, it is easy to see that each of b's (absolute) temporal parts is located at the same temporal point throughout its career, and hence that each of them is located at the same spatial point throughout its career. And if each of an object's temporal parts is at rest, so to speak, then so is the aggregate of these parts." Thus, although b might appear to be moving quite rapidly-it should be clear that no one denies the appearance of motion-this appearance is illusory, since b does not move. In spite of these considerations, I contend that there is a sense of movement which is applicable to four-dimensional objects. The first step towards seeing this involves recalling that three-dimensionalism and fourdimensionalism are both accounts of persistence, i.e., they are both accounts of what it is for a single object to exist at different times. In particular, they are both accounts of persistence through change, i.e., accounts of what it is for a single object to be F at one time and not-F at another. As I pointed out in Chapter Three, three-dimensionalists generally account for this possibility by saying that properties are indexical. According to Peter van Inwagen, we are free to think of the indexicality of properties in either of two ways (1990a, 247). That is, saying that an object is Fat t) involves saying either that this object bears the relation of having to the time-indexed property Fat-t), or else that this object bears a time-indexed relation having-at-r, to the

20

l owe this point to Greg Ganssle.

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For David Lewis, one of the great virtues of fourproperty F. dimensionalism is that it does not have to construe monadic properties as disguised relations: a four-dimensional object can be F at one time and not-F at another in virtue of its having one temporal part which is F and another which is not-F. Just as we can speak of both three- and four-dimensional objects as persisting--even though we are dealing with very different accounts of persistence-we can also speak of both sorts of objects as changing, even though we are dealing with very different accounts of change. For the sake of clarity, I shall use an asterisk (as in change*) to indicate that I am using 'change' (or its cognates) in the same way that Lewis uses 'persist', i.e., in a way that applies equally to three- and four-dimensional objects. And just as we use 'endure' to denote the sort of persistence enjoyed by threedimensional objects, while we use 'perdure' to denote the sort of persistence enjoyed by four-dimensional objects, we should similarly disambiguate between the sense of change which is applicable to three-dimensional objects, and the sense which is applicable to four-dimensional objects. Let 'change,' (and its cognates) stand for the first sort of change, and let 'change,' stand for the second sort. With these points in mind, I would like to make the following observations: (1) It is a mistake to say that four-dimensional objects do not change*, just as it is to say that three-dimensional objects do not change*. (2) It is both uninformative and potentially misleading to say that fourdimensional objects do not changes, just as it is to say that threedimensional objects do not changes." (3) We can truly say that four-dimensional objects changea, just as we can truly say that three-dimensional objects changej. (4) If material objects persist by enduring through time in their entirety, then these objects change* by changingj. (5) If material objects persist by perduring, then these objects change* by changinga. While these observations are not terribly enlightening, they shall soon lead us to observations which do strike me as enlightening. For, I shall argue, each of these statements has an analogue which involves a particular sort of change, namely, motion. This statement is uninformative because it is true by definition. It is potentially misleading because it might lead one (especially one who is not clear on the ambiguity of "change") to think that four-dimensional objects do not change*. In other words, this statement is uninformative and potentially misleading in the same way that 'fish do not breathe' is, where breathing is defined as a process of oxygen transfer which involves the use of lungs. For this might be taken to (falsely) suggest that fish do not respire. 21

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According to David Lewis, only the four-dimensional account of change is able to explain how it is possible for an object to have different intrinsic properties at different times (1986, 203f). But there is no reason why this account of change needs to be restricted to an object's intrinsic properties. Indeed, this account of change works just as well for an object's relational properties, like the property of being at least as tall as Bill Clinton, or the property of being inside St. Paul's Cathedral. For just as a four-dimensional object can change from being white to non-white by having one stage which is white, and a later stage which is not, such an object can have one stage which is shorter than Bill Clinton, and a later stage which is not. And I see no reason why the same cannot be said for the second relational property mentioned above: a four-dimensional object can change from having this property to having its negation by having one temporal part which is inside St. Paul' s Cathedral, and by having a later part which is not.22 Since a four-dimensional account of change is capable of explaining how a temporally extended object can be in one place at t1 and in another place at t2, this account of change can also explain how it is possible for fourdimensional objects to move . For Locke and Newton both have what we might call a minimalist conception of motion. That is, they both think that motion involves nothing more than change of place. In De gravitatione, for example, Newton defines rest as 'remaining in the same place' , and he defines motion as 'change of place' (122).23 Similarly, in ll.xxii .16 Locke contends that spirits are mobile, since spirits are capable of changing place, with the implication being that change of place is a sufficient condition for mobility. If motion involves nothing more than being in different places at different times, and these object's exist in different places at different times by having different temporal parts in these places, then it follows that temporally extended objects move by having different temporal parts in different places. Thus it is clear that 'move' is ambiguous in the same way that 'change' is. For the sake of clarity, I shall once again use an asterisk (as in move *) to indicate that I am using 'move' in an intentionally ambiguous way, i.e., in a way that applies equally well to sort of movement undergone by threedimensional objects, and to the sort undergone by four-dimensional objects. Let 'move,' (and its cognates) stand for the first sort of movement, and let 'move;' stand for the second sort. We these points in mind, the above observations give rise to the following analogues:

22 These explanations are obviously a little more complicated if Bill Clinton and St. Paul's Cathedral are themselves four-dimensional objects, as Quine and McTaggart contend. 23 See definitions three and four.

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It is a mistake to say that four-dimensional objects do not move *, just as it is to say that three-dimensional objects do not move *. (2') It is both uninformative and potentially misleading to say that fourdimensional objects do not mover, just as it is to say that threedimensional objects do not movea. (3') We can truly say that four-dimensional objects movea, just as we can truly say that three-dimensional objects movej. (4') If material objects persist by enduring through time in their entirety, then these objects move* by moving- , (5') If material objects persist by perduring, then these objects move * by movinga. If we allow that three-dimensionalism and four-dimensionalism are both accounts persistence, we must allow that they are accounts of persistence through change. And if we allow this, then I think that we have to accept the first set of observations listed above . Moreover, if we think, with Locke and Newton, that motion involves nothing more than change of place, then we must also accept the second set of observations. Since these observations indicate that there is a sense of motion which is applicable to four-dimensional objects, I contend that Locke would not have to reject four-dimensional atoms on the grounds that they are immobile.

(1')

III. CONCLUSION

In this chapter I have defended my four-dimensional interpretation of Locke's identity chapter against the objection, first, that it is blatantly anachronistic, and second, that it is at odds with his corpuscularianism. In response to the first objection, I showed that Locke could have endorsed a four-dimensional account of persons and organisms, that he possessed all of the necessary conceptual machinery for such this position. I subsequently argued that his isomorphic treatment of space and time provides us with an additional reason for thinking that Locke would have been favorably disposed towards this account. In response to the second objection, I argued that his endorsement of Newton's creation theory shows that he is not strongly committed to the corpuscularian hypothesis. For he was surely aware this theory of creation is incompatible with the received (= corpuscularian) account of bodies . I subsequently argued that his endorsement of this creation theory provides us with an yet another reason for think ing that the material objects in Locke's ontology have both spatial and temporal extent. For if God created atoms in the way that Newton and Locke have speculated, and these atoms are capable of existing in different

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places at different times, as Newton and Locke both allow , then it follows that an atom is a divinely-modified region of space-time. On the basis of these considerations alone, I am confident that Locke would have rejected three-dimensionalism in favor of four-dimensionalism, had he been presented with a clear choice between the two. In the final chapter of this work I shall present what I take to be the most compelling reason for affirming this conclusion, to wit, that his theory of identity is incompatible with his anti-essentialism on a three-dimensional ontology, but not on a four-dimensional ontology.

6

RELATIVISTIC ANTI-ESSENTIALISM AND A FOUR-DIMENSIONAL LOCKEAN ONTOLOGY

Let us briefly return to the dilemma which confronts Locke if the physical objects in his ontology persist by enduring through time in their entirety. On a three-dimensional ontology, he is not just giving persistence conditions for these objects, he is giving endurance conditions for these objects. Moreover, he must be specifying either absolute or relative endurance conditions, that is, the conditions under which these objects cease enduring, absolutely, or the conditions under which these objects cease enduring only relative to a given sortal concept. Here, once more, is the dilemma: he cannot offer relative endurance conditions for particular objects without committing himself to a relativized notion of identity, which is inconsistent with his principle of individuation. And he cannot offer absolute endurance conditions for particular objects without attributing de re essential properties to these objects, which is inconsistent with the second facet of his antiessentialism, which states that there are many, equally legitimate ways of sorting individuals into kinds. The final conclusion of this book is that these theories are indeed compatible, despite strong appearances to the contrary. Since the above dilemma rests on the assumption that the physical objects in Locke's ontology persist by enduring through time, this dilemma shows that Locke's anti-essentialism is compatible with his theory of identity only if these objects persist by perduring through time. In this chapter I argue that these theories are compatible if these objects persist by perduring. In particular, I argue that if the organisms and persons in his ontology persist by having temporal extent, then these theories are compatible, since on this ontology Locke can offer both a relativistic account of persistence (in accordance with his with his relativistic anti-essentialism), and a non-relativistic or absolute account of identity (in accordance with his principle of individuation). Since I have already provided (in Chapters Four and Five) three independent arguments for the thesis that the physical objects in Locke's ontology do have temporal extent, I conclude that these theories are compatible. 175 C. H. Conn (ed.), Locke On Essence and Identity © Kluwer Academic Publishers 2004

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I. THE ANTI-ESSENTIALIST IMPLICATIONS OF A FOUR-DIMENSIONAL LOCKEAN ONTOLOGY

I. The sortal relativity offour-dimensional persistence conditions If the objects in Locke's ontology persist by being temporally extended, then he is offering perdurance conditions for these objects. That is, he is specifying the cross-temporal unity conditions for an F, the conditions under which successively existing object-stages are stages of the same F. For purposes of illustration, let us suppose that we have before us a series of ten, temporally continuous object-stages. Let' SI' stand for the first of these stages, let ' S 2' stand for the second, and so on. Furthermore, let us stipulate that these stages are related in variou s ways. First , let us suppose that s\ and S2 together compose a single , temporally extended mass of matter m), that 53 and S4 compose a distinct mass of matter m-; and so on for the three remaining pairs of successive stages. Second, let us suppose that these stages are all life-related to one another, but that they are not all consciousrelated to one another. Rather, in a manner which is akin to the Day ManlNight Man case, let us suppose that the odd-numbered stages are all consciousness-related to one another, that the even-numbered stages are all consciousness-related to one another, but that no even- numbered stages are so related to any odd-numbered stages or vice versa. With this scenario in hand, I would first like to establish that fourdimensional persistence conditions are inescapably sortal relative. Note, in the first place, that each of these stages is a mass-stage, a man-stage, a person-stage. In addition, note that since all of these stages are life-related to one another, they are all stages of the same man. In contrast, they are not all stages of the same mass, nor of the same person. Thus, for example, SI and S 2 are stages of the same mass, but they are stages of different persons, while SI and S3 are stages of the same person, but of different masse s. Since two successively existing stages can be stage s of the same person but of different masses, we cannot meaningfully ask whether these stages belong to the same thing, simpliciter. Rather, we must ask whether they belong to the same F, and the answer will depend upon the unity conditions which are supplied by our concept of an F. In support of this conclusion, Quine writes in "Worlds Away" that the "identification of an object from moment to moment takes on content only when we indicate what sort of object we want" (1981, 125). In a footnote to this passage Quine makes the following observation: My point is strangely reminiscent of Geach 's contention [in (Geach , 1962)] that "it makes no sense to judge whether x and y are 'the

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same' ...unless we add or understand some general term-the same F'" (§31). I say "strangely" because I disagree with Geach; I insist that x and yare the same F if and only if x and y are the same, outright, and Fx. Cross-temporal identification is another thing: the momentary objects x and yare unwaveringly distinct, but are time slices of perhaps the same F and different G's. (125n.2)

As Quine points out, it is the relation of cross-temporal unity which is sortal relative, and not the relation of identity. Subsequent to drawing attention to this passage, James Van Cleve makes a similar observation, noting that "there is also something in all of this akin to the doctrine that identity is conventional. As before, it is not identity that has the feature in question, but [cross-temporal] unity" (1986, 153). Locke would do well to concur with Quine and Van Cleve at this juncture. While he (implicitly) rejects a relativized notion of identity, I think he must accept a relativistic account of persistence, given his conventionalism with respect to kinds and essences, in conjunction with his idea principle, which states that the persistence conditions for a particular object is largely a function of the sortal concept which one associates with this object. In connection with his identity chapter, we can see this conventionalism at work in insistence that we are free to associate different concepts with an object, provided that we do so consistently. In particular, he requires merely that we work with a single notion of what it is to be an F in the process of determining whether the F which is