Human Knowledge and Human Nature: A New Introduction to an Ancient Debate

Human Knowledge and Human Nature = 1 A N E W INTRODUCTION T O AN ANCIENT DEBATE PETER CARRUTHERS HUMAN KNOWLEDGE A...

Author: Peter Carruthers

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Human Knowledge and

Human Nature

= 1 A N E W INTRODUCTION T O AN ANCIENT

DEBATE

PETER CARRUTHERS

HUMAN KNOWLEDGE AND HUMAN NATURE A new introduction to an ancient debate

PETER

CARRUTHERS

O X F O R D UNIVERSITY PRESS 1992

Oxford

University

Press,

Oxford Delhi

Bombay

Petaling

jaya

Nairobi

Walton Street,

Neiv York Calcutta

Singapore Dares

Madras

Salaam

Melbourne

Cape

Tokyo

Town

Auckland

Berlin

in

Ibadan

Oxford is a trade mark of Oxford Published

Karachi

Hong Kong

and associated companies

by Oxford

Oxford o x 2 6DP

Toronto

University

in the United

University

Press

States

Press, New

© Peter Carruthers

York

1992

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press This book is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, resold, hired out or otherwise circulated without the publisher's prior consent in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser British Library Cataloguing Data Library of Congress Human

knowledge

in Publication

Cataloging

Carruthers,

Peter,

and human

nature

ancient debate I Peter p. Includes 1.

Knowledge,

3. BD161.C352

: a new introduction

to an

Carruthers. and

Innate ideas

index. (Philosophy)

1. Title.

121—dc20

91-23735

ISBN 0-19-875101-X ISBN 0-19-875102-8 (pbk.)

Printed

Data

1952-

references 2.

Empiricism. 1992

in Publication

cm.

bibliographical Theory of.

Data

available

Typeset by Pentacor PLC in Great Britain by Biddies Guildford & King's Lynn

Ltd,

Contents Preface 1. Introduction: M o d e s of K n o w l e d g e

vii 1

2. K n o w l e d g e out of Reason: Platonism

17

3. The Empiricist Case against Platonism

33

4. The Empiricist Case against Nativism

48

5. Is Innate K n o w l e d g e even Possible?

64

6. The Case for Innate Mental Structure

79

7. The Case for Innate C o n c e p t s

95

8. The Case for Innate K n o w l e d g e

111

9. P o w e r s of Mind: The Core of Empiricism

127

10. Evolutionary Nativism and A Priori Knowledge

143

11. O u r K n o w l e d g e of the External World

159

12. K n o w l e d g e by Best Explanation

174

Conclusion

192

Further Reading

195

Index

197

for Isaac blank slate

Preface T H I S b o o k b e g a n life as a series of l e c t u r e s that w e r e n e v e r d e l i v e r e d . In the s p r i n g of 1 9 8 8 I w a s invited to take part in the s e c o n d S i n o - B r i t i s h S u m m e r S c h o o l in P h i l o s o p h y , d u e to h a v e b e e n h e l d in B e i j i n g in A u g u s t 1 9 8 9 . T h e idea w a s to p r o d u c e w r i t t e n texts of t h e l e c t u r e s , b o t h to b e m a d e available to t h o s e a t t e n d i n g t h e S u m m e r S c h o o l , a n d for later p u b l i c a t i o n in C h i n e s e t r a n s l a t i o n . I b e g a n w o r k that J u l y , a n d h a d t h e l e c t u r e s c o m p l e t e d b y the f o l l o w i n g M a y . B u t t h e n t h e s e s s i o n of the S u m m e r S c h o o l w a s u n f o r t u n a t e l y c a n c e l l e d , f o l l o w i n g the s u p p r e s s i o n of the p r o - d e m o c r a c y d e m o n s t r a t i o n s in T i a n a n m e n S q u a r e by t h e P e o p l e ' s L i b e r a t i o n A r m y o n 4 J u n e 1 9 8 9 . M y original brief w a s to w r i t e on British E m p i r i c i s m for a n a u d i e n c e of C h i n e s e a c a d e m i c s a n d g r a d u a t e s t u d e n t s w h o s e English might not be perfect, and w h o , while having s o m e k n o w l e d g e of e m p i r i c i s m a n d of W e s t e r n p h i l o s o p h y g e n e r a l l y , w o u l d h a v e h a d little e x p e r i e n c e of active w o r k w i t h i n o u r tradition. A c c o r d i n g l y , I w a s to teach n o t o n l y by c o n t e n t b u t b y e x a m p l e . T h a t spirit h a s s u r v i v e d i n t o t h e p r e s e n t b o o k . N o t o n l y h a v e I tried to p r o v i d e a clear a n d s u c c i n c t i n t r o d u c t i o n to m a n y of t h e i s s u e s in t h e t h e o r y of k n o w l e d g e particularly relating to e m p i r i c i s m , b u t I h a v e also a t t e m p t e d to m a k e a n original c o n t r i b u t i o n to t h e s u b j e c t , t h e r e b y illustrating h o w s e r i o u s w o r k in p h i l o s o p h y c a n at t h e s a m e t i m e b e a c c e s s i b l e . I also h a d t h e idea that m y l e c t u r e s m i g h t f o r m a u s e f u l m o d e l o f h o w o n e c a n take p a s t t r a d i t i o n s of t h o u g h t s e r i o u s l y w h i l e at t h e s a m e t i m e r e t a i n i n g a critical d i s t a n c e — t r y i n g , f r o m o u r c o n t e m p o r a r y p e r s p e c t i v e , b o t h t o r e w o r k t h e i n s i g h t s a n d to a v o i d t h e e r r o r s of h i s t o r y . T h a t spirit, t o o , h a s s u r v i v e d i n t o t h e p r e s e n t b o o k . I a m g r a t e f u l to N i c k B u n n i n , as C h a i r m a n of t h e British C o m m i t t e e of t h e S u m m e r S c h o o l , for e x t e n d i n g m e t h e

viii

Preface

original i n v i t a t i o n . T h e texts of m y l e c t u r e s w e r e p r e p a r e d u n d e r t h e title ' E m p i r i c i s m , N a t i v i s m a n d A Priori K n o w l e d g e ' . I a m grateful to t h e f o l l o w i n g i n d i v i d u a l s for their a d v i c e , a n d for criticisms of earlier d r a f t s : D a v i d A r c h a r d , A n g e l a B l a c k b u r n , N i c k B u n n i n , B o b H a l e , Sile H a r r i n g t o n , S u s a n L e v i , C y n t h i a M a c d o n a l d , A l a n Millar, D a v i d S m i t h , N i c h o l a s W h i t e , T i m W i l l i a m s o n , X i a o Y a n g , a n d t w o a n o n y m o u s r e a d e r s for O x f o r d U n i v e r s i t y P r e s s . I a m also grateful to m y s t u d e n t s at the U n i v e r s i t i e s of E s s e x a n d of M i c h i g a n , w h o w e r e o b l i g e d to s t u d y earlier drafts of t h e b o o k a s a text, a n d w h o g a v e m e the b e n e f i t of their o b j e c t i o n s a n d — e q u a l l y i m p o r t a n t — t h e i r frequent incomprehension. S o m e of the i d e a s in this b o o k h a v e b e e n d e l i v e r e d as talks at t h e U n i v e r s i t y of East A n g l i a , t h e U n i v e r s i t y of M i c h i g a n , the 1990 J o i n t S e s s i o n of the Aristotelian S o c i e t y a n d M i n d A s s o c i a t i o n , a n d Trinity C o l l e g e D u b l i n . I a m grateful to all t h o s e w h o p a r t i c i p a t e d in the s u b s e q u e n t d i s c u s s i o n s for their c o m m e n t s a n d criticisms. S o m e of t h e material in C h a p t e r s 9 a n d 10 h a s b e e n p r e v i o u s l y p u b l i s h e d u n d e r the title ' W h a t is E m p i r i c i s m ? ' in t h e Proceedings of the Aristotelian Society ( s u p p l e m e n t a r y v o l u m e 6 4 , 1990). I a m grateful to t h e Editor of the Proceedings for p e r m i s s i o n to m a k e u s e of it. O n e final n o t e : t h r o u g h o u t this b o o k I shall u s e t h e colloquial plural p r o n o u n s ' t h e y ' a n d ' t h e i r ' in i m p e r s o n a l c o n t e x t s , in p l a c e of t h e m a s c u l i n e s i n g u l a r ' h e ' a n d ' h i s ' r e q u i r e d b y strict E n g l i s h g r a m m a r . I b e l i e v e that g r a m m a r n e e d s c h a n g i n g in this r e s p e c t , s i n c e it c o n t r i v e s to give t h e a p p e a r a n c e that o n l y m e n e v e r d o or t h i n k a n y t h i n g w o r t h m e n t i o n i n g .

P.C. Sheffield April

1991

1 Introduction: Modes of Knowledge T H I S b o o k is a b o u t t h e t h e o r y of k n o w l e d g e , f o c u s i n g e s p e c i a l l y o n d e b a t e s b e t w e e n e m p i r i c i s m a n d v a r i o u s f o r m s of r a t i o n a l i s m . In this first c h a p t e r I shall o u t l i n e t h e n a t u r e of m y p r o j e c t , w h i c h is to r e a s s e s s t h e c l a i m s of classical e m p i r i c i s m f r o m o u r present perspective.

Problems of K n o w l e d g e W e c a n d i s t i n g u i s h t h r e e d i m e n s i o n s a l o n g w h i c h t h e o r i e s of k n o w l e d g e m a y differ f r o m o n e a n o t h e r . T h e r e c a n b e d i s p u t e a b o u t t h e extent of h u m a n k n o w l e d g e , a b o u t t h e sources of h u m a n k n o w l e d g e , a n d also a b o u t w h a t k n o w l e d g e itself is. I shall say s o m e t h i n g briefly a b o u t e a c h of t h e s e t h r e e d i m e n s i o n s in t u r n . First, p h i l o s o p h e r s m a y d i s a g r e e with o n e a n o t h e r a b o u t t h e e x t e n t of h u m a n k n o w l e d g e , a b o u t how much w e m a y b e said to k n o w . A t o n e e n d of t h e scale are v a r i o u s k i n d s of s c e p t i c , w h o claim that w e k n o w v e r y little, or at least a g o o d deal less t h a n w e t h i n k w e d o . E x t r e m e s c e p t i c s c l a i m , for e x a m p l e , that w e c a n k n o w n o t h i n g b e y o n d o u r o w n c u r r e n t s t a t e s of c o n s c i o u s n e s s — t h a t is, o u r o w n p r e s e n t t h o u g h t s a n d e x p e r i e n c e s . At t h e o t h e r e n d of t h e scale are v a r i o u s s o r t s of realist, w h o m a i n t a i n that w e k n o w a g o o d d e a l a b o u t o u r s e l v e s a n d the w o r l d a r o u n d u s . B e t w e e n t h e s e t w o p o l e s t h e r e is s p a c e for m a n y intermediate positions. O n e that m a y b e w o r t h m e n t i o n i n g in p a r t i c u l a r is p h e n o m e n a l i s m . P h e n o m e n a l i s t s a l l o w that m o s t of o u r o r d i n a r y b e l i e f s a b o u t p h y s i c a l o b j e c t s d o c o n s t i t u t e k n o w l e d g e , but only u n d e r a particular (non-realist) interpreta t i o n . T h e y claim t h a t such, b e l i e f s d o n o t really c o n c e r n a w o r l d

2

Introduction

of o b j e c t s e x i s t i n g i n d e p e n d e n t l y of o u r m i n d s , b u t relate o n l y to r e c u r r i n g p a t t e r n s w i t h i n o u r e x p e r i e n c e . W h e n I s p e a k of t h e c h a i r o n w h i c h I a m sitting, for e x a m p l e , t h e y c l a i m t h a t I a m really o n l y r e f e r r i n g to a familiar b u n d l e of e x p e r i e n c e s , w h i c h is a p t to r e c u r periodically w i t h i n t h e s t r e a m of m y c o n s c i o u s n e s s . S o w h i l e I d o p e r h a p s k n o w that t h e c h a i r e x i s t s , a n d m a y c o n t i n u e to k n o w this e v e n in its a b s e n c e , this is n o t really k n o w l e d g e of a n y t h i n g o u t s i d e m y o w n m i n d . Secondly, there may be disagreement about the possible s o u r c e s of h u m a n k n o w l e d g e , a b o u t t h e a v e n u e s t h r o u g h w h i c h w e m a y h o p e to o b t a i n k n o w l e d g e . A t o n e e x t r e m e is t h e p o s i t i o n a d o p t e d by classical e m p i r i c i s t s s u c h a s L o c k e a n d H u m e , w h o c l a i m e d that t h e o n l y s o u r c e of s u b s t a n t i v e k n o w l e d g e is e x p e r i e n c e ( u n d e r s t o o d b r o a d l y to i n c l u d e b o t h m e m o r y a n d i n t r o s p e c t i o n ) . At t h e o t h e r e x t r e m e is t h e v i e w of Plato, w h o h e l d , o n t h e c o n t r a r y , that e x p e r i e n c e c a n n o t yield g e n u i n e k n o w l e d g e , s i n c e it c o n c e r n s s t a t e s a n d o b j e c t s that a r e c o n s t a n t l y c h a n g i n g . H e c l a i m e d that t h e o n l y s o u r c e of true k n o w l e d g e is t h e h u m a n intellect, w h i c h m a y o b t a i n for u s k n o w l e d g e of t h e u n c h a n g i n g w o r l d of F o r m s , or u n i v e r s a l s . In b e t w e e n t h e s e t w o , lies t h e p o s i t i o n o f classical r a t i o n a l i s t s s u c h as D e s c a r t e s a n d L e i b n i z , w h o m a i n t a i n e d that k n o w l e d g e m a y b e o b t a i n e d both t h r o u g h e x p e r i e n c e and t h r o u g h t h e u s e of p u r e intellect. P l a t o ' s v i e w h a s b e e n e n d o r s e d b y a l m o s t n o o n e s i n c e , a n d n e e d n o t d e t a i n u s h e r e . It d e r i v e s f r o m his p e c u l i a r c o n c e p t i o n of t h e n a t u r e of k n o w l e d g e . But w e shall b e v e r y m u c h c o n c e r n e d w i t h t h e d i s p u t e b e t w e e n classical e m p i r i c i s m a n d classical r a t i o n a l i s m . I n d e e d , it will f o r m t h e m a i n f o c u s of this book. Finally, philosophers may disagree about w h a t k n o w l e d g e itself is, a b o u t h o w t h e c o n c e p t of k n o w l e d g e s h o u l d p r o p e r l y b e d e f i n e d . T h i s i s s u e h a s n o t l o o m e d v e r y large in t h e w o r k o f m o s t t h e o r i s t s of k n o w l e d g e s i n c e P l a t o , at l e a s t until v e r y r e c e n t l y . B u t in o u r o w n era a v a r i e t y of a c c o u n t s h a v e b e e n p r o p o s e d . All a r e a g r e e d that in o r d e r to c o u n t as k n o w l e d g e s o m e t h i n g m u s t at l e a s t b e b e l i e v e d a n d b e t r u e — y o u c a n n o t k n o w that g r a s s is g r e e n u n l e s s y o u b e l i e v e t h a t g r a s s is g r e e n , a n d u n l e s s it is in fact true t h a t g r a s s is g r e e n . All are e q u a l l y a g r e e d that t h e r e is m o r e to k n o w l e d g e t h a n m e r e t r u e belief. D i f f e r e n c e s arise as to w h a t t h e third c o m p o n e n t of k n o w l e d g e m i g h t b e . S o m e h o l d that it is j u s t i f i c a t i o n , s o m e t h a t it is

c a u s a t i o n b y t h e fact t h a t is b e l i e v e d to o b t a i n , s o m e t h a t it is c a u s a t i o n b y a reliable p r o c e s s . W e shall r e t u r n to t h e s e i s s u e s in s o m e detail in C h a p t e r 5. It is u s u a l for b o o k s o n t h e t h e o r y o f k n o w l e d g e to b e g i n w i t h a d i s c u s s i o n of s c e p t i c i s m . I p r o p o s e , h o w e v e r , t o r e s e r v e m y c o n s i d e r a t i o n of t h i s i s s u e until last. For h o w w e h a n d l e it m a y d e p e n d v e r y m u c h u p o n w h a t w e t h i n k a b o u t t h e n a t u r e of k n o w l e d g e , a n d its p o s s i b l e s o u r c e s . M o r e o v e r , t h e r e a r e , in a n y c a s e , a g o o d m a n y i s s u e s that c a n b e d i s c u s s e d w i t h o u t r e f e r r i n g to t h e p r o b l e m of s c e p t i c i s m . T h e s e are p r o b a b l y b e s t t r e a t e d first. For in m y e x p e r i e n c e , w h e n s o m e o n e h a s o n c e b e e n i n t r o d u c e d to t h e p r o b l e m of s c e p t i c i s m it is h a r d to p e r s u a d e t h e m to t a k e s e r i o u s l y a n y o t h e r i s s u e i n t h e t h e o r y o f k n o w l e d g e . It is t r u e , h o w e v e r , t h a t a n y c o n c l u s i o n s w e m a y r e a c h c a n o n l y b e p r o v i s i o n a l . F o r if, in t h e e n d , t h e e x t r e m e s c e p t i c c a n n o t b e a n s w e r e d , t h e n it m a y t u r n o u t t h a t w e c a n k n o w n o t h i n g a b o u t a n y of t h e s e o t h e r i s s u e s . W h a t is distinctive a b o u t c o n t e m p o r a r y d e b a t e s i n t h e t h e o r y of k n o w l e d g e is that t h e y m o s t l y b y p a s s a l t o g e t h e r t h e q u e s t i o n of t h e p o s s i b l e s o u r c e s of h u m a n k n o w l e d g e . All t h e a t t e n t i o n is d e v o t e d to w h a t k n o w l e d g e itself i s , a n d to a t t e m p t s t o d e f e n d o r to u n d e r m i n e v a r i o u s f o r m s of s c e p t i c i s m . It will b e o n e of t h e t h e m e s of this b o o k that s u c h a c o n c e n t r a t i o n of effort is a m i s t a k e . In m y v i e w , t h e c o r r e c t d e f i n i t i o n of k n o w l e d g e is a g o o d deal less s i g n i f i c a n t t h a n is s o m e t i m e s t h o u g h t . A n d it s h o u l d b e o b v i o u s that t h e q u e s t i o n of t h e e x t e n t of h u m a n k n o w l e d g e s i m p l y c a n n o t b e a n s w e r e d w i t h o u t c o n s i d e r i n g its p o s s i b l e s o u r c e s . O n this i s s u e ( a s , a r g u a b l y , o n m a n y o t h e r s ) w e c a n o n l y m a k e p r o g r e s s b y r e t u r n i n g t o t h e historical r o o t s o f o u r c u r r e n t d e b a t e s . A c c o r d i n g l y , I shall n o w s a y s o m e t h i n g further about the dispute b e t w e e n empiricists a n d rationalists c o n c e r n i n g t h e q u e s t i o n of h o w k n o w l e d g e m a y b e o b t a i n e d , f o c u s i n g initially o n h o w e m p i r i c i s m itself s h o u l d p r o p e r l y b e characterized.

Empiricism: A n Initial Sketch Empiricists have defended two distinctive negative theses about t h e s o u r c e s of h u m a n k n o w l e d g e , w h i c h m a y o r m a y n o t b e i n t i m a t e l y c o n n e c t e d w i t h o n e a n o t h e r (I shall l e a v e this o p e n

Introduction

4

for t h e m o m e n t ) . First, t h e y h a v e b e e n o p p o s e d t o a n y f o r m of n a t i v i s m , for e x a m p l e d e n y i n g that a n y c o n c e p t or a n y k n o w l e d g e is i n n a t e ( i n b o r n ) . S e c o n d l y , t h e y h a v e d e n i e d that w e m a y o b t a i n s u b s t a n t i v e k n o w l e d g e of t h e w o r l d a priori, i n s i s t i n g r a t h e r that all s u c h k n o w l e d g e m u s t b e g r o u n d e d in e x p e r i e n c e . ( T h e n o t i o n of t h e a priori c a n b e u n d e r s t o o d in e i t h e r of t w o distinct w a y s — m o s t u s u a l l y , a s k n o w l e d g e w h i c h c a n b e a r r i v e d at b y a p r o c e s s of t h o u g h t a l o n e , o r , a l t e r n a t i v e l y , as k n o w l e d g e w h i c h is n o t l e a r n e d from e x p e r i e n c e . T h e d i f f e r e n c e is n o t at p r e s e n t i m p o r t a n t , b u t will later p r o v e s o . ) 1 shall shortly say s o m e t h i n g a b o u t e a c h of t h e s e s t r a n d s , r e t u r n i n g to t h e m in g r e a t e r detail in s u b s e q u e n t c h a p t e r s . B u t first I w a n t to m a k e s o m e r e m a r k s a b o u t f u r t h e r c a n d i d a t e s for i n c l u s i o n in o u r initial c h a r a c t e r i z a t i o n of e m p i r i c i s m . M o s t e m p i r i c i s t s h a v e also b e e n f o u n d a t i o n a l i s t s , m a i n t a i n i n g that the a r c h i t e c t u r e of o u r k n o w l e d g e c o n s i s t s of a s u p e r s t r u c t u r e s u p p o r t e d by f o u n d a t i o n s . T h e y h a v e h e l d that s o m e of o u r b e l i e f s , particularly r e p o r t s of i m m e d i a t e e x p e r i e n c e or s e n s e - d a t a , h a v e a privileged p o s i t i o n with r e s p e c t to t h e o t h e r s , p r o v i d i n g t h e m with their u l t i m a t e s u p p o r t . (In c o n t r a s t , c o h e r e n t i s t s h o l d that k n o w l e d g e m a y b e c h a r a c t e r i z e d as a set of m u t u a l l y c o h e r e n t a n d s u p p o r t i v e t r u e b e l i e f s . W h i l e f o u n d a tionalists picture k n o w l e d g e in the s h a p e of a b u i l d i n g , s t a n d i n g o n a f o u n d a t i o n , c o h e r e n t i s t s p i c t u r e it as a sort of n e t — p e r h a p s s p i n n i n g u n s u p p o r t e d in d e e p s p a c e — h e l d t o g e t h e r by t h e i n t e r n a l t e n s i o n s b e t w e e n its e l e m e n t s . ) But f o u n d a t i o n a l i s m c a n h a r d l y h a v e b e e n distinctive of e m p i r i c i s m , s i n c e all classical r a t i o n a l i s t s , t o o , h a v e s h a r e d a similar c o m m i t m e n t to it. D e s c a r t e s , for e x a m p l e , h e l d that all k n o w l e d g e m u s t b e f o u n d e d o n t h e data of i m m e d i a t e e x p e r i e n c e t o g e t h e r w i t h s i m p l e t r u t h s of r e a s o n . F o u n d a t i o n a l i s m m a y t u r n o u t to b e a n e c e s s a r y i n g r e d i e n t in e m p i r i c i s m , h o w e v e r , e v e n if it is b y n o m e a n s distinctive of it. T h i s possibility will b e left o p e n for n o w . A m o r e p l a u s i b l e c a n d i d a t e for i n c l u s i o n in o u r initial a c c o u n t of e m p i r i c i s m is a c o m m i t m e n t to p h e n o m e n a l i s m , s i n c e m o s t e m p i r i c i s t s h a v e b e l i e v e d that all o u r k n o w l e d g e m u s t in t h e e n d r e d u c e to k n o w l e d g e of patterns in o u r o w n subjective e x p e r i e n c e . B u t t h e r e a r e t w o t h i n g s w r o n g w i t h this s u g g e s t i o n . T h e first is that it i g n o r e s t h e p o s i t i o n of L o c k e , w h o certainly t h o u g h t that w e c o u l d h a v e k n o w l e d g e of o b j e c t s o u t s i d e o u r s e l v e s . A d m i t 1

1

S e e his Essay Concerning

Human

Understanding,

b k . iv, c h . xi.

Introduction

5

tedly, h i s a r g u m e n t s for this v i e w a r e w e a k , a n d m o s t later e m p i r i c i s t s h a v e b e l i e v e d that h e w a s i n c o n s i s t e n t i n failing to embrace phenomenalism, given his general claims about the g e n e s i s of c o n c e p t s a n d of k n o w l e d g e . B e t h a t as it m a y , w e c a n h a r d l y m a i n t a i n t h a t a c o m m i t m e n t to p h e n o m e n a l i s m is f u n d a m e n t a l to his p o s i t i o n , g i v e n h i s o w n explicit r e j e c t i o n of the doctrine. T h e s e c o n d t h i n g w r o n g w i t h t h e a b o v e s u g g e s t i o n is that p h e n o m e n a l i s m is b e s t v i e w e d a s a c o n s e q u e n c e of t h e t h r e e s t r a n d s a l r e a d y m e n t i o n e d , r a t h e r t h a n a s a distinct c o n c e r n in its o w n right. F o r t h e r e j e c t i o n of n a t i v i s m m e a n s t h a t all o u r b e l i e f s m u s t in t h e e n d b e d e c o m p o s a b l e i n t o c o n c e p t s that c a n b e derived from e x p e r i e n c e . T h i s , together with f o u n d a t i o n a l i s m , t h e n a c c o r d s t h e data of i m m e d i a t e e x p e r i e n c e a c e n t r a l p o s i t i o n w i t h i n t h e overall s t r u c t u r e of o u r k n o w l e d g e . A n d w h e n this is c o m b i n e d w i t h o p p o s i t i o n to s u b s t a n t i v e a priori k n o w l e d g e , w e a p p e a r to h a v e t h e i m p l i c a t i o n that o u r k n o w l e d g e c a n r e a c h n o further than patterns within the data of i m m e d i a t e experience itself. I shall r e t u r n to c o n s i d e r t h e p o s s i b l e c o n n e c t i o n b e t w e e n p h e n o m e n a l i s m a n d a n t i - n a t i v i s m in m o r e detail in c h a p t e r 1 1 . F o r t h e m o m e n t t h e i s s u e m a y b e left to o n e s i d e . O n e f u r t h e r c a n d i d a t e for i n c l u s i o n in o u r initial c h a r a c t e r i z a tion of e m p i r i c i s m w o u l d b e a c o m m i t m e n t to t h e i m a g i s t t h e o r y of t h i n k i n g . O n this v i e w , all t h o u g h t s c o n s i s t of s e q u e n c e s of m e n t a l i m a g e s , a n d all c o n c e p t s c o m e to r e p r e s e n t their o b j e c t s in v i r t u e of r e s e m b l i n g t h e m . W h i l e L o c k e ' s c o m m i t m e n t to i m a g i s m is h a l f - h e a r t e d , a n d d o e s n o s e r i o u s w o r k w i t h i n t h e a r g u m e n t a t i v e s t r u c t u r e of t h e Essay, in t h e w r i t i n g s of B e r k e l e y a n d H u m e it a p p e a r s to b e m o r e significant. In The Principles of Human Knowledge, for e x a m p l e , Berkeley argues f r o m i m a g i s m as a p r e m i s s to t h e c o n c l u s i o n that it is i m p o s s i b l e for u s e v e n to t h i n k a b o u t a n i n d e p e n d e n t m a t e r i a l reality, c l a i m i n g t h a t a n idea c a n b e l i k e — c a n r e s e m b l e — n o t h i n g b u t a n o t h e r i d e a , a n d t h a t it is i m p o s s i b l e for u s to i m a g e a n u n e x p e r i e n c e d o b j e c t . H u m e , t o o , s e e m s to e n d o r s e s u c h a p o s i t i o n . 2

It is d o u b t f u l , h o w e v e r , w h e t h e r i m a g i s m is really i n d e p e n d ent of the t w o negative strands in e m p i r i c i s m already m e n t i o n e d , particularly o p p o s i t i o n to n a t i v i s m . F o r t h e m a j o r a t t r a c t i o n of i m a g i s m , for e m p i r i c i s t s , is t h a t it p r o v i d e s t h e m w i t h a n a p p a r e n t l y p l a u s i b l e t h e o r y of c o n c e p t a c q u i s i t i o n . If c o n c e p t s 2

S e e h i s Treatise of Human

Nature,

bk. i, p t . n, s e c t , vi a n d bk. i, p t . iv, s e c t . n.

Introduction

6

are i m a g e s — m e n t a l p i c t u r e s — t h e n it is e a s y to s e e h o w t h e y m i g h t b e a c q u i r e d t h r o u g h e x p e r i e n c e , b y a p r o c e s s of copying. O n this a c c o u n t , t h e c o n c e p t s w e d e p l o y in t h i n k i n g will b e s i m p l y r e p r o d u c e d a s p e c t s of e x p e r i e n c e , laid d o w n earlier in m e m o r y . W e shall r e t u r n to e m p i r i c i s t t h e o r i e s of c o n c e p t a c q u i s i t i o n in s o m e detail in c h a p t e r 4 . F o r t h e m o m e n t , t h e p o i n t is that t h e r e is n o r e a s o n to i n c l u d e a c o m m i t m e n t to imagism within our primary characterisation of empiricism. R a t h e r , that c o m m i t m e n t is b e s t u n d e r s t o o d as a n a t u r a l c o n s e q u e n c e of t h e e m p i r i c i s t t h e s i s that all c o n c e p t s m u s t b e acquired from experience.

Representation a n d Truth W e h a v e j u s t n o w t o u c h e d u p o n i s s u e s that h a v e b e e n the s u b j e c t of m u c h r e c e n t d e b a t e a m o n g s t p h i l o s o p h e r s of m i n d a n d of l a n g u a g e , c o n c e r n i n g the n a t u r e of r e p r e s e n t a t i o n a n d of t r u t h . W h a t all a r e n o w u n i t e d o n is t h a t t h e i m a g i s t t h e o r y of t h o u g h t is h o p e l e s s l y i n a d e q u a t e , b u t t h e r e is a g r e e m e n t u p o n little e l s e . S o m e s t r a n d s in this d e b a t e n e e d to b e m e n t i o n e d briefly h e r e , if o n l y to b e set to o n e s i d e . 3

O n e i s s u e of n o t e c o n c e r n s the c o n t r a s t that c a n b e d r a w n b e t w e e n c o h e r e n c e c o n c e p t i o n s of truth o n t h e o n e h a n d , a n d c o r r e s p o n d e n c e c o n c e p t i o n s on t h e o t h e r . W h i l e c o h e r e n t i s t s a b o u t k n o w l e d g e h o l d (as w e s a w briefly a b o v e ) t h a t t h e j u s t i f i c a t i o n for a belief c o n s i s t s in its m e m b e r s h i p of a suitably c o h e r e n t s e t of b e l i e f s , c o h e r e n t i s t s a b o u t t r u t h g o f u r t h e r . T h e y m a i n t a i n that for a b e l i e f to b e true j u s t is for it to b e a m e m b e r of a s u i t a b l y c o h e r e n t set. C o r r e s p o n d e n c e t h e o r i s t s , o n t h e o t h e r h a n d , m a i n t a i n that for a b e l i e f to b e true is for it to c o r r e s p o n d to t h e f a c t s . M i n i m a l l y , t h e y m a i n t a i n that for a b e l i e f or s t a t e m e n t t o b e t r u e , t h e r e m u s t b e s o m e f a c t — s o m e s t a t e of a f f a i r s — i n v i r t u e of w h i c h it is t r u e . T h e i d e a h e r e is t h a t o u r b e l i e f s h a v e to m e a s u r e u p to a n i n d e p e n d e n t l y g i v e n reality. I i n t e n d to p r e s u p p o s e a c o r r e s p o n d e n c e c o n c e p t i o n of t r u t h F o r a n i n t r o d u c t o r y e x p o s i t i o n o f t h e w a y in w h i c h i s s u e s in t h e t h e o r y o f m e a n i n g m a y h a v e b e a r i n g o n t h e t h e o r y o f k n o w l e d g e , s e e J. D a n c y , An Introduction to Contemporary Epistemology ( O x f o r d : B l a c k w e l l , 1 9 8 5 ) . 3

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t h r o u g h o u t t h e c o u r s e of t h i s b o o k , f o r r e a s o n s t h a t I shall n o w briefly e x p l a i n . A n o b v i o u s difficulty for c o h e r e n c e c o n c e p t i o n s of t r u t h is that it t h e n s e e m s quite p o s s i b l e t h a t a belief m i g h t b e t r u e at o n e t i m e b u t false at a n o t h e r , w i t h o u t t h e r e b e i n g a n y r e l e v a n t c h a n g e in its s u b j e c t - m a t t e r . F o r e x a m p l e , t h e belief that t h e E a r t h is flat f o r m e d p a r t of a c o h e r e n t a n d m u t u a l l y s u p p o r t i v e set of b e l i e f s in t h e f i f t e e n t h c e n t u r y , b u t n o l o n g e r d o e s s o t o d a y . D o e s this t h e n m e a n that it was o n c e true that t h e E a r t h is flat, b u t that it is s o n o l o n g e r ? C o h e r e n t i s t s a p p e a r t o h a v e t w o p o s s i b l e a v e n u e s of r e s p o n s e . O n e is to claim that r e p r e s e n t a tion, a n d h e n c e b e l i e f - c o n t e n t , a r e a l s o a m a t t e r o f c o h e r e n c e . O n t h i s a c c o u n t t h e r e will b e n o g e n u i n e conflict b e t w e e n o u r b e l i e f s a n d t h o s e of t h e fifteenth c e n t u r y b e c a u s e , t h r o u g h b e i n g e m b e d d e d within different coherent sets, the beliefs they assert are n o t t h e s a m e as t h e o n e s w e d e n y . T h e o t h e r o p t i o n is to i n t r o d u c e a c o n s i d e r a b l e d e g r e e of idealization i n t o t h e a c c o u n t of c o h e r e n c e , for e x a m p l e c l a i m i n g that to c o u n t a s t r u e a b e l i e f m u s t b e l o n g to a set that i n c o r p o r a t e s a n d e x p l a i n s all p o s s i b l e past and future observational data. N e i t h e r of t h e a b o v e o p t i o n s a p p e a r s at all attractive. It s e e m s u n d e n i a b l e that I d o c o n t r a d i c t t h e b e l i e f s of t h e f i f t e e n t h c e n t u r y by a s s e r t i n g that t h e E a r t h is r o u n d . A n d e v e n if w e c a n i m a g i n e w h a t it w o u l d b e like to b e in p o s s e s s i o n of a m a x i m a l l y c o h e r e n t t h e o r y i n c o r p o r a t i n g all p o s s i b l e o b s e r v a t i o n a l d a t a , it s e e m s to r e m a i n a n o p e n q u e s t i o n w h e t h e r or n o t that t h e o r y w o u l d b e t r u e — w h e t h e r it w o u l d m a t c h u p to t h e f a c t s . I n d e e d , t h e c o h e r e n c e c o n c e p t i o n of t r u t h (like p h e n o m e n a l i s m , a s w e shall s e e in c h a p t e r 11) is b e s t u n d e r s t o o d a s a r e t r e a t f r o m a n initial r e a l i s m d e s i g n e d t o o u t f l a n k s c e p t i c i s m , b y defining t r u t h as w h a t o u r b e s t ( m o s t c o h e r e n t ) t h e o r y w o u l d d e s c r i b e . B u t if it is p o s s i b l e to a r g u e a g a i n s t s c e p t i c i s m directly, as I shall s u g g e s t in c h a p t e r s 11 a n d 12 that it i s , t h e n t h e c o h e r e n c e t h e o r y of t r u t h will b e i n a d e q u a t e l y m o t i v a t e d . E v e n a m o n g s t t h o s e w h o e n d o r s e s o m e v e r s i o n of a c o r r e s p o n d e n c e t h e o r y of t r u t h , t h e r e r e m a i n d i s p u t e s a b o u t t h e e x t e n t to w h i c h t r u t h is g e n u i n e l y o b j e c t i v e . R e a l i s t s a b o u t t r u t h m a i n t a i n t h a t it is, e a c h o n e of o u r b e l i e f s a b o u t t h e w o r l d b e i n g d e t e r m i n a t e l y true or false i r r e s p e c t i v e of w h e t h e r w e are c a p a b l e ( e i t h e r in p r a c t i c e or i n p r i n c i p l e ) o f d i s c o v e r i n g its

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status. Anti-realists, in contrast, m a i n t a i n that truth is c o n s t r a i n e d b y r e l a t i o n s of e p i s t e m i c a c c e s s i b i l i t y — i n its s t r o n g e s t v e r s i o n , c l a i m i n g that t h e r e is n o t r u t h e x c e p t verifiable t r u t h ; in w e a k e r v e r s i o n s , c l a i m i n g that t h e r e can o n l y b e truth w h e r e t h e r e c a n b e e v i d e n c e that b e a r s o n t r u t h . S i n c e this is a d i s p u t e arising o u t of c o n s i d e r a t i o n s in t h e t h e o r y of m e a n i n g (or of r e p r e s e n t a tion g e n e r a l l y ) , it w o u l d take u s too far o u t of o u r w a y to d i s c u s s it p r o p e r l y h e r e . But m y o w n p o s i t i o n is that it is in v i r t u e of o u r c o n c e p t u a l c a p a c i t i e s — o u r abilities to i d e n t i f y a n d classify i t e m s in t h e w o r l d — t h a t o u r t h o u g h t s c o m e to r e p r e s e n t w h a t t h e y d o ; a n d that o u r b e s t t h e o r y of o u r c o n c e p t u a l c a p a c i t i e s , w h e n e m b e d d e d w i t h i n o u r b e s t t h e o r y of t h e material w o r l d a n d o u r relation to it, is o n e that s u p p o r t s a realist c o n c e p t i o n of t r u t h . I shall r e t u r n to t h e m a t t e r briefly in c h a p t e r 12. F o r t h e m o s t part I shall s i m p l y a s s u m e , for p u r p o s e s of a r g u m e n t , that t r u t h is i n d e e d o b j e c t i v e . O u r q u e s t i o n is w h e t h e r w e h a v e knowledge of a n y t r u t h s , a n d if s o , h o w — t h a t is, w h e t h e r w e m a y b e realists a b o u t k n o w l e d g e as well a s realists a b o u t t r u t h . 4

5

6

T w o Strands in Empiricism Let me n o w r e t u r n to c o n s i d e r t h e t w o m a i n s t r a n d s w i t h i n t h e e m p i r i c i s t tradition in a little m o r e detail. E m p i r i c i s t s , as I s a y , h a v e b e e n u n i t e d in their o p p o s i t i o n to n a t i v i s m , w h e t h e r concerning innate knowledge, innate beliefs, innate concepts, or i n n a t e m e n t a l s t r u c t u r e s e m b o d y i n g i n f o r m a t i o n a b o u t p a r t i c u l a r d o m a i n s of k n o w l e d g e , s u c h a s l a n g u a g e or v i s i o n . T h e y h a v e i n s i s t e d , o n t h e c o n t r a r y , t h a t all o u r k n o w l e d g e a n d b e l i e f s m u s t in o n e w a y or a n o t h e r b e d e r i v e d f r o m e x p e r i e n c e ; that all c o n c e p t s m u s t e i t h e r b e a b s t r a c t a b l e f r o m e x p e r i e n c e or d e f i n a b l e in t e r m s of c o n c e p t s that c a n b e s o a b s t r a c t e d ; a n d that all t h e p s y c h o l o g i c a l m e c h a n i s m s i n v o l v e d i n l e a r n i n g are g e n e r a l o n e s , t h e s a m e for all d o m a i n s of k n o w l e d g e . H e r e t h e r e S e e A . J. A y e r , Language, Truth and Logic ( L o n d o n : G o l l a n c z , 1 9 3 6 ) for t h e classic d e f e n c e of such a position. M i c h a e l D u m m e t t h a s d e f e n d e d a p o s i t i o n o f this s o r t . S e e m a n y o f t h e p a p e r s in h i s Truth and Other Enigmas ( L o n d o n : D u c k w o r t h , 1978). See also C r i s p i n W r i g h t , Realism, Meaning and Truth ( O x f o r d : B l a c k w e l l , 1 9 8 6 ) . O n t h i s s e e m y Tractarian Semantics ( O x f o r d : B l a c k w e l l , 1 9 8 9 ) , c h . 1 0 . 4

5

6

9

Introduction

is s h a r p conflict w i t h t h o s e w h o b e l o n g to t h e rationalist t r a d i t i o n , i n c l u d i n g P l a t o , D e s c a r t e s a n d L e i b n i z (as w e l l as contemporary writers such as N o a m C h o m s k y and Jerry Fodor). M u c h of o u r a t t e n t i o n in this b o o k will b e f o c u s e d o n this d e b a t e , especially in c h a p t e r s 4 - 8 . W h i l e e m p i r i c i s t s h a v e b e e n o p p o s e d to n a t i v i s m in a n y of t h e a b o v e f o r m s , it is w o r t h s t r e s s i n g that t h e y h a v e n o t r e j e c t e d all forms of i n n a t e n e s s . O n the contrary, they h a v e characteristically h e l d that t h e d i v i s i o n of t h e m i n d i n t o distinct faculties (for e x a m p l e , i n t o s e n s a t i o n , i m a g i n a t i o n , a n d u n d e r s t a n d i n g ) is i n n a t e l y g i v e n . T h e y h a v e also h e l d that t h e b a s i c p s y c h o l o g i c a l p r o c e s s e s i n v o l v e d in t h e v a r i o u s m o d e s of a c q u i r i n g o u r b e l i e f s are i n n a t e , s u c h as p r i n c i p l e s o f a s s o c i a t i o n a m o n g s t o u r i d e a s . ( I n d e e d , t h e y are s u r e l y o b l i g e d to h o l d s u c h a v i e w . F o r o n e c a n n o t , f r o m n o t h i n g , l e a r n h o w to l e a r n . ) S o m e e m p i r i c i s t s h a v e e v e n h e l d v i e w s that c a n b e d e s c r i b e d a s naturalistic, r e l y i n g u p o n a s p e c t s of a n i n n a t e l y g i v e n h u m a n n a t u r e t o p r o v i d e p a r t of their s u g g e s t e d s o l u t i o n to s o m e p r o b l e m . F o r e x a m p l e , H u m e ' s position c o n c e r n i n g o u r belief in t h e c o n t i n u e d e x i s t e n c e of p h y s i c a l o b j e c t s is naturalistic in this s e n s e , s i n c e h e h o l d s t h a t , g i v e n o u r n a t u r e , w e c a n n o t b u t b e l i e v e that i t e m s s u c h a s t a b l e s a n d c h a i r s c o n t i n u e to exist u n p e r c e i v e d . B u t this is n o t to a s c r i b e to u s i n n a t e k n o w l e d g e of t h e p h y s i c a l w o r l d . N o r is it to claim that t h e faculty t h r o u g h w h i c h w e a c q u i r e this belief (the faculty of i m a g i n a t i o n , in H u m e ' s v i e w ) is s t r u c t u r e d in s u c h a w a y as to c o n t a i n i n n a t e i n f o r m a t i o n a b o u t t h e w o r l d . H i s i d e a is s i m p l y that t h e g e n e r a l l a w s of h u m a n p s y c h o l o g y e n s u r e that w e shall h a v e b e l i e f s c o n c e r n i n g t h e c o n t i n u e d e x i s t e n c e of p h y s i c a l o b j e c t s , i r r e s p e c t i v e of sceptical a r g u m e n t s to t h e c o n t r a r y . 7

8

E m p i r i c i s t s h a v e also b e e n u n i t e d in d e n y i n g that w e c a n attain s u b s t a n t i v e k n o w l e d g e of t h e w o r l d a priori. T h e y h a v e i n s i s t e d , o n t h e c o n t r a r y , that all s u b s t a n t i v e k n o w l e d g e is e m p i r i c a l , n e e d i n g to b e g r o u n d e d in e x p e r i e n c e . T h e y are t h e n i m m e d i a t e l y p r e s e n t e d w i t h a c h a l l e n g e . N a m e l y , to p r o v i d e s o m e a c c o u n t of o u r k n o w l e d g e of logic a n d m a t h e m a t i c s , n e i t h e r of w h i c h a p p e a r s to b e at all e m p i r i c a l . I shall n o w s p e n d S e e t h e Treatise, b k . i, p t . iv. O n this s e e P . F . S t r a w s o n , Skepticism 1985). 7

8

and Naturalism

(London:

Methuen,

10

Introduction

s o m e t i m e o u t l i n i n g a n d d i s c u s s i n g t h e m a n n e r in w h i c h e m p i r i c i s t s h a v e a t t e m p t e d to reply to this c h a l l e n g e . T h e m a j o r i t y h a v e c h o s e n to r e s p o n d via a p a r t i c u l a r i n t e r p r e t a t i o n of t h e s u b j e c t - m a t t e r of t h o s e d i s c i p l i n e s , s u c h a s m a t h e m a t i c s , w h i c h a r e a priori. T h e y h a v e c l a i m e d that t h e t r u t h s of logic a n d m a t h e m a t i c s are analytic, b e i n g c o n c e r n e d o n l y w i t h internal r e l a t i o n s b e t w e e n o u r c o n c e p t s (ideas) t h e m s e l v e s . S o t h e k n o w l e d g e that w e h a v e of t h e s e t r u t h s d o e s n o t c o n c e r n a n y a s p e c t of t h e w o r l d i n d e p e n d e n t of o u r m i n d s , e x c e p t in s o far as o u r c o n c e p t s m a y h a v e b e e n d e r i v e d f r o m e x p e r i e n c e of such a w o r l d . H e r e e m p i r i c i s m m a y p r o p e r l y b e c o n t r a s t e d w i t h p l a t o n i s m . For the p l a t o n i s t b e l i e v e s , o n t h e c o n t r a r y , that t h e p r o p o s i t i o n s of logic a n d m a t h e m a t i c s c o n c e r n an abstract (non-physical and changeless) but genuinely m i n d i n d e p e n d e n t realm of o b j e c t s , i n c l u d i n g u n i v e r s a l s s u c h as b e a u t y a n d w i s d o m , as well as m a t h e m a t i c a l e n t i t i e s s u c h a s t h e n a t u r a l n u m b e r s ( 1 , 2, 3 , e t c . ) a n d t h e p e r f e c t s q u a r e . T h i s d e b a t e , t o o , will o c c u p y u s c o n s i d e r a b l y in t h e c h a p t e r s that f o l l o w , especially in c h a p t e r s 2 a n d 3 , a n d again in c h a p t e r 10. S o m e e m p i r i c i s t s h a v e b e e n i n c l i n e d to d i s p a r a g e analytic t r u t h s as b e i n g trivial a n d u n i n f o r m a t i v e . T h i s is a d e f i n i t e m i s t a k e . Plainly s o m e a n a l y t i c t r u t h s a r e t r i v i a l — n e i t h e r ' E v e r y t h i n g is identical w i t h i t s e l f n o r 'It is e i t h e r r a i n i n g or n o t r a i n i n g ' a r e likely to b e n e w s to a n y o n e . B u t m a n y a r e n o t , o n l y b e i n g r e c o g n i z e d for t h e first t i m e a f t e r t h e c o l l a b o r a t i v e l a b o u r of m a n y g e n e r a t i o n s of thinkers. I n d e e d , a great m a n y important scientific d i s c o v e r i e s h a v e o n l y b e e n m a d e p o s s i b l e b y c o n c e p tual or m a t h e m a t i c a l a d v a n c e . T h i s is w h y I elected to c h a r a c t e r ize t h e p r e s e n t s t r a n d in e m p i r i c i s m b y s a y i n g that it c o n s i s t s in d e n y i n g that t h e r e is substantive a priori k n o w l e d g e of t h e w o r l d , r a t h e r t h a n b y s a y i n g that it is t h e d e n i a l of informative a priori k n o w l e d g e . (By k n o w l e d g e that is s u b s t a n t i v e , I shall u n d e r stand k n o w l e d g e w h i c h is either c o n t i n g e n t — a s is o u r k n o w l e d g e of o u r o w n s t a t e s of m i n d a n d o u r o w n e x i s t e n c e — o r w h i c h c o n c e r n s entities t h a t exist i n d e p e n d e n t l y of t h e h u m a n m i n d — a s d o e s m a t h e m a t i c a l k n o w l e d g e , g i v e n a p l a t o n i s t a c c o u n t of t h e s u b j e c t - m a t t e r of m a t h e m a t i c s . ) In m y v i e w t h e d e b a t e b e t w e e n e m p i r i c i s t s a n d p l a t o n i s t s o u g h t p r o p e r l y to c o n c e r n t h e s u b j e c t - m a t t e r of logic a n d m a t h e m a t i c s , n o t its u s e f u l n e s s or c o g n i t i v e s i g n i f i c a n c e .

11

Introduction

S o m e later empiricists (notably Mill a n d Q u i n e ) h a v e a d o p t e d a r a t h e r d i f f e r e n t m a n n e r of r e s p o n d i n g to t h e c h a l l e n g e p r o v i d e d b y o u r k n o w l e d g e of logic a n d m a t h e m a t i c s . T h e y h a v e d e n i e d that s u c h k n o w l e d g e ( i n d e e d a n y k n o w l e d g e ) is really a priori. O n this v i e w , t h e p r o p o s i t i o n s of m a t h e m a t i c s , like all o t h e r p r o p o s i t i o n s , are c o n t i n g e n t a n d e m p i r i c a l — t h e y c o u l d p o s s i b l y b e f a l s e , a n d are d e r i v e d u l t i m a t e l y f r o m e x p e r i e n c e . B u t t h e y exist at a h i g h level of a b s t r a c t i o n a n d g e n e r a l i t y , v e r y far r e m o v e d f r o m t h e i m p a c t of e x p e r i e n c e . It is this that g i v e s rise to t h e illusion that t h e y m a y g e n u i n e l y b e k n o w n i n d e p e n d e n t l y of t h e c o u r s e of o u r e x p e r i e n c e , a n d that t h e y o b t a i n n e c e s s a r i l y , in all c o n c e i v a b l e s i t u a t i o n s . R a t h e r , s u c h t r u t h s , like a n y o t h e r s , a r e g r o u n d e d in e x p e r i e n c e a n d r e v i s a b l e in p r i n c i p l e in t h e light of f u t u r e e x p e r i e n c e . It is j u s t that their c o n n e c t i o n w i t h e x p e r i e n c e is n o t easily n o t i c e d , d u e to t h e i r a b s t r a c t n e s s . 9

Q u i n e ' s f a m o u s i m a g e of o u r b e l i e f s as c o n s t i t u t i n g a w e b , o n l y c o n n e c t i n g w i t h e x p e r i e n c e directly at t h e p e r i p h e r y , p r o v i d e s a g r a p h i c illustration of this i d e a . W e a r e to p i c t u r e o u r b e l i e f s as f o r m i n g a n i n t e r c o n n e c t e d n e t w o r k , s o m e of w h o s e m e m b e r s ( t h e p e r i p h e r y ) are direct r e p o r t s of e x p e r i e n c e , w h e r e a s o t h e r s ( s u c h a s p r o p o s i t i o n s of logic) a r e v e r y far r e m o v e d f r o m it. C h a n g e s at t h e p e r i p h e r y o c c a s i o n a l t e r a t i o n s e l s e w h e r e in t h e n e t w o r k , n o n e of o u r beliefs b e i n g i m m u n e f r o m p o s s i b l e r e v i s i o n . W h i c h of o u r beliefs s h o u l d in fact b e r e v i s e d in face of t h e c h a n g i n g c o u r s e of o u r e x p e r i e n c e will b e a m a t t e r of w h a t a d j u s t m e n t s w o u l d p r o v i d e u s w i t h t h e m o s t s a t i s f y i n g overall e x p l a n a t i o n . T h e t r u t h s of logic, a l t h o u g h in p r i n c i p l e r e v i s a b l e , a r e h a r d l y e v e r a l t e r e d b e c a u s e of t h e m a s s i v e c h a n g e s this w o u l d o c c a s i o n e l s e w h e r e in t h e n e t w o r k . T h e r e will a l m o s t a l w a y s b e m o r e e c o n o m i c a l w a y s o f a c c o m m o d a t i n g recalcitrant e x p e r i e n c e s . 1 0

T h e t r o u b l e w i t h s u c h a n a c c o u n t , h o w e v e r , is to e x p l a i n h o w a n y c h a n g e s in belief m a y rationally b e r e q u i r e d of u s , if all b e l i e f s a r e e q u a l l y e m p i r i c a l . If all o u r b e l i e f s face t h e t r i b u n a l of e x p e r i e n c e t o g e t h e r , t h e n t h e r e is n o t h i n g to give s u b s t a n c e to the idea that s o m e a d j u s t m e n t s of belief are rationally d e m a n d e d of u s in t h e face of o t h e r a l t e r a t i o n s e l s e w h e r e in t h e n e t w o r k . S e e J. S. Mill, A System of Logic ( L o n d o n : L o n g m a n s , 1 8 7 9 ) a n d W . V. Q u i n e , From a Logical Point of Vieiv ( C a m b r i d g e , M a s s . : H a r v a r d U n i v e r s i t y P r e s s , 1 9 5 3 ) . S e e ' T w o D o g m a s of E m p i r i c i s m , in From a Logical Point of View. 9

1 0

12

Introduction

O n t h e c o n t r a r y , all c h a n g e s in t h e n e t w o r k of b e l i e f will b e m e r e l y c a u s a l , it b e i n g a p u r e l y p s y c h o l o g i c a l m a t t e r w h a t c h a n g e s will t a k e p l a c e w i t h i n a s u b j e c t ' s b e l i e f s in r e s p o n s e to a n y g i v e n e x p e r i e n c e . In o r d e r for t h e i d e a of a rationally r e q u i r e d c h a n g e to m a k e s e n s e , s o m e at least of o u r b e l i e f s m u s t b e h e l d c o n s t a n t , f u n c t i o n i n g a s n o r m s that m e d i a t e c h a n g e s a m o n g s t t h e o t h e r s . T h i s is p r e c i s e l y t h e role traditionally a c c o r d e d to t h e a priori p r o p o s i t i o n s of logic a n d m a t h e m a t i c s . H o w e v e r , to insist that p r o p o s i t i o n s of logic a n d m a t h e m a t i c s f u n c t i o n a s n o r m s , a n d are h e n c e n o t empirical ( n o t l e a r n e d from e x p e r i e n c e ) , is n o t n e c e s s a r i l y to g r a n t that their s t a t u s is i n v i o l a b l e . W h a t a n e m p i r i c i s t s h o u l d say a b o u t this m a t t e r will d e p e n d u p o n w h e t h e r or n o t t h e y t h i n k that a n a l y t i c t r u t h s are o b j e c t i v e . S o m e , like A y e r , h a v e h e l d that t h e y a r e , reflecting m i n d - i n d e p e n d e n t relations b e t w e e n c o n c e p t s ( w h o s e existence, in t u r n , is n o t p l a t o n i c b u t mind-dependent). Others, following t h e later W i t t g e n s t e i n , w o u l d d e n y t h i s , h o l d i n g that a p r o p o s i tion a c h i e v e s a priori s t a t u s s o m e w h a t as f o l l o w s . F i n d i n g o u r s e l v e s p s y c h o l o g i c a l l y i n c a p a b l e of s e e i n g h o w a g i v e n p r o p o s i t i o n (such as '15 + 17 = 3 2 ' ) c o u l d b e f a l s e , w e a d o p t t h e c o n v e n t i o n of e l e v a t i n g t h e r e s u l t s of s u c h l i m i t a t i o n s to t h e s t a t u s of a n o r m o f d e s c r i p t i o n , u s i n g it h e n c e f o r w a r d to m e d i a t e c h a n g e s b e t w e e n o t h e r b e l i e f s . B u t this s t a t u s n e e d n o t b e i n v i o l a b l e : w h a t is a n e c e s s a r y t r u t h (a n o r m ) at o n e t i m e , m a y c e a s e to b e s o at a n o t h e r . I shall n o t p u r s u e t h e s e i d e a s a n y f u r t h e r in this b o o k . S u f f i c e it to say t h a t e v e n g r a n t i n g that t h e r e e x i s t s a class of a n a l y t i c t r u t h s , t h e r e r e m a i n difficult q u e s t i o n s c o n c e r n i n g t h e o b j e c t i v e or s u b j e c t i v e s t a t u s of s u c h truths. 11

1 2

W e h a v e c a n v a s s e d t w o w a y s in w h i c h e m p i r i c i s t s , w h o d e n y that a n y s u b s t a n t i v e k n o w l e d g e m a y b e o b t a i n e d a priori, m i g h t r e s p o n d to t h e c h a l l e n g e p r o v i d e d b y logic a n d m a t h e m a t i c s . O n e is to m a i n t a i n that o u r k n o w l e d g e w i t h i n t h e s e d o m a i n s , w h i l e a priori, is a n a l y t i c . T h e o t h e r is to d e n y t h a t o u r k n o w l e d g e of logic a n d m a t h e m a t i c s is g e n u i n e l y a priori. T h e i r o n l y r e m a i n i n g o p t i o n is a p p a r e n t l y to t a k e t h e radical s t e p of 1 1

S e e A y e r , Language,

Truth and Logic, c h . 4 .

T h o s e i n t e r e s t e d m a y like t o r e a d C r i s p i n W r i g h t , Wittgenstein on the Foundations of Mathematics ( L o n d o n : D u c k w o r t h , 1 9 8 0 ) , p t . in. S e e a l s o m y Metaphysics of the Tractatus ( C a m b r i d g e : C a m b r i d g e U n i v e r s i t y P r e s s , 1 9 9 0 ) , c h s . 4 , 11 a n d 1 5 . 1 2

Introduction

13

d e n y i n g that a n y p r o p o s i t i o n s of logic o r m a t h e m a t i c s a r e true. F e w e m p i r i c i s t s h a v e t a k e n this c o u r s e , for o b v i o u s r e a s o n s . B u t it h a s b e e n d e f e n d e d r e c e n t l y b y H a r t r y F i e l d . I shall r e t u r n to c o n s i d e r this o p t i o n briefly in c h a p t e r 2. B u t I shall m o s t l y a s s u m e that t h e correct s t r a t e g y for a n e m p i r i c i s t is to a l l o w that logic a n d m a t h e m a t i c s are a priori, a n d c o n t a i n m a n y k n o w n t r u t h s , b u t to d e n y that t h e y a r e substantive—that t h e y give u s k n o w l e d g e of a n y t h i n g that exists i n d e p e n d e n t l y of t h e h u m a n mind. 13

H a v i n g said s o m e t h i n g a b o u t t h e q u e s t i o n s that b e l o n g to t h e t h e o r y of k n o w l e d g e in g e n e r a l , a n d t h e n a t u r e of t h e e m p i r i c i s t m o v e m e n t in particular, it is n o w t i m e to o u t l i n e w h a t I plan to d o in this b o o k .

The Project T h e b a s i c a i m of this b o o k is to r e c o n s t i t u t e a n d d e f e n d t h e e s s e n t i a l s of t h e e m p i r i c i s t tradition f r o m w i t h i n o u r c o n t e m p o r ary p e r s p e c t i v e . T h e m a j o r q u e s t i o n to b e a s k e d is w h e t h e r a n y o n e t o d a y c a n b e j u s t i f i e d in b e i n g an e m p i r i c i s t , or w h e t h e r , on the contrary, empiricism has n o w b e e n decisively s u p e r s e d e d . I shall b e a r g u i n g for t h e f o r m e r of t h e s e o p t i o n s . T h i s is d e s p i t e t h e fact that o n e of t h e t w o m a i n s t r a n d s w i t h i n classical e m p i r i c i s m ( n a m e l y , t h e d e n i a l of n a t i v i s m ) h a s c o m e u n d e r i n c r e a s i n g p r e s s u r e in r e c e n t y e a r s ( a n d rightly s o , as w e shall s e e in later c h a p t e r s ) . I shall b e a r g u i n g that t h e c o r e of e m p i r i c i s m , if p r o p e r l y c h a r a c t e r i z e d , r e m a i n s as v i b r a n t a n d d e f e n s i b l e t o d a y a s it e v e r w a s . M y a i m s are t h u s b o t h to p r o v i d e a particular i n t e r p r e t a t i o n of t h e n a t u r e of t h e e m p i r i c i s t tradition a n d also to d e f e n d that tradition ( t h e latter partly via the former). W h i l e I shall o c c a s i o n a l l y c o m m e n t u p o n specific classic t e x t s , I shall m o s t l y t a k e t h e b r o a d o u t l i n e s of their a u t h o r s ' v i e w s for g r a n t e d . It s h o u l d b e e m p h a s i z e d , h o w e v e r , that I shall n o t t a k e e m p i r i c i s m to b e d e f i n e d at t h e o u t s e t b y a n y p a r t i c u l a r set of ideas a n d d o c t r i n e s — a n d certainly not by the two m a i n strands a l r e a d y d i s t i n g u i s h e d . F o r a g o o d d e a l of w h a t is at i s s u e h e r e is S e e h i s Science without Numbers (Oxford: Blackwell, Mathematics and Modality ( O x f o r d : B l a c k w e l l , 1 9 8 9 ) . 1 3

1980) and

Realism,

14

Introduction

w h a t c o n s t i t u t e s t h e t r u e c o r e of e m p i r i c i s m . T h i s is a m a t t e r , n o t of explicit d o c t r i n e s , b u t of f u n d a m e n t a l m o t i v a t i o n s . It m a y b e o b j e c t e d that t h e t e r m ' e m p i r i c i s m ' , as g e n e r a l l y u n d e r s t o o d , m a y s i m p l y b e defined as t h e d o c t r i n e that all k n o w l e d g e m u s t b e g r o u n d e d in e x p e r i e n c e . S o q u e s t i o n s of m o t i v a t i o n arise n o t at all, a n d it f o l l o w s i m m e d i a t e l y that e m p i r i c i s m is i n c o n s i s t e n t w i t h n a t i v i s m . W i t h this I d i s a g r e e . W h i l e o u r g r a s p of e m p i r i c i s m m a y b e partially c h a r a c t e r i z e d b y t h e c l a i m e d c o n n e c t i o n b e t w e e n k n o w l e d g e a n d e x p e r i e n c e , it s e e m s to m e u n d e n i a b l e that it is also partly g o v e r n e d b y o u r a c q u a i n t a n c e with t h e v i e w s d e f e n d e d by t h o s e g e n e r a l l y k n o w n a s ' e m p i r i c i s t s ' . ( A n a n a l o g y f r o m literature: w h i l e o u r u n d e r s t a n d i n g of t h e t e r m ' r o m a n t i c i s m ' m a y b r i n g to m i n d a particular d e f i n i t i o n , it is also partially c h a r a c t e r i z e d by o u r k n o w l e d g e of t h e w o r k s of t h o s e g e n e r a l l y d e s c r i b e d as ' r o m a n t i c s ' . ) It is this t e x t - b a s e d s t r a n d in t h e n o t i o n of e m p i r i c i s m t h a t b e c o m e s p r i m a r y w h e n w e raise t h e q u e s t i o n of o u r o w n r e l a t i o n s h i p to traditional e m p i r i c i s m . In this sort of c a s e w h a t w e w i s h to k n o w is w h e t h e r o u r o w n v i e w s a r e or a r e n o t in c o n f o r m i t y w i t h t h e basic c o n c e r n s of earlier e m p i r i c i s t s . O u r q u e s t i o n is t h e e x t e n t to w h i c h w e m a y c o u n t o u r s e l v e s as b e l o n g i n g to t h e s a m e tradition of t h o u g h t . R a t h e r t h a n u n d e r s t a n d e m p i r i c i s m to b e d e f i n e d b y a n y p a r t i c u l a r s e t of d o c t r i n e s , I shall t a k e t h e central texts of L o c k e a n d H u m e as representative of the motivation b e h i n d empiricism in g e n e r a l , particularly t h e f o r m e r ' s Essay a n d t h e l a t t e r ' s Treatise a n d Enquiry Concerning Human Understanding. F o r I t h i n k that if these authors had n e v e r written, o n e would never have thought of s e e i n g e n o u g h in c o m m o n b e t w e e n p h i l o s o p h e r s s u c h a s B a c o n , H o b b e s , a n d Berkeley to describe t h e m all as 'empiricists'; b u t that t h e r e v e r s e is n o t t h e c a s e . T h e i s s u e b e f o r e u s m a y u s e f u l l y b e c o n s i d e r e d in t e r m s of t h e n o t i o n s of core a n d periphery. W h a t w e shall n e e d is to d i s t i n g u i s h b e t w e e n t h o s e a s p e c t s of t h e e m p i r i c i s t t r a d i t i o n t h a t c o n s t i t u t e its c o r e (that are g e n u i n e l y e s s e n t i a l to it), a n d t h o s e that a r e m e r e l y p e r i p h e r a l ( t h a t c o u l d b e g i v e n u p w i t h o u t l o s i n g a n y t h i n g of f u n d a m e n t a l i m p o r t a n c e ) . T h i s is a m a t t e r of d i s c o v e r i n g w h a t it w a s t h a t t h e classical e m p i r i c i s t s w e r e m o s t c o n c e r n e d to e s t a b l i s h or s h o w . F o r if, a s I shall a r g u e , t h e e m p i r i c i s t o p p o s i t i o n t o n a t i v i s m t u r n s o u t to b e a d e f i n i t e

Introduction

15

m i s t a k e , t h e n w e shall n e e d to k n o w w h e t h e r t h i s a s p e c t of t h e tradition m a y simply b e cut a w a y from the remainder, leaving a c o h e r e n t b o d y of d o c t r i n e intact that is still r e c o g n i z a b l y e m p i r i c i s t in spirit. W e shall t h e r e f o r e n e e d to k n o w w h i c h , if e i t h e r , of t h e t w o m a i n s t r a n d s in classical e m p i r i c i s m is t h e m o r e f u n d a m e n t a l , or w h e t h e r t h e r e m i g h t b e s o m e f u r t h e r c h a r a c t e r i z a t i o n of t h e c o r e of e m p i r i c i s m that w o u l d e x p l a i n its c o m m i t m e n t to b o t h . S u c c e s s f u l c o m p l e t i o n of m y p r o j e c t will t h u s r e q u i r e t w o t h i n g s . First, a n a s s e s s m e n t of t h e t r u t h or falsity of t h e t w o m a i n d o c t r i n e s that h a v e traditionally b e e n d e f e n d e d b y e m p i r i c i s t s . T h i s task will o c c u p y u s t h r o u g h the m a j o r part o f this b o o k . S e c o n d , w e shall n e e d a n a c c o u n t of t h e e s s e n t i a l c o r e of e m p i r i c i s m that will e m b r a c e w h a t is t r u e , w h i l e a l l o w i n g u s to e x c l u d e w h a t is f a l s e . T h i s will form t h e topic of c h a p t e r s 9 a n d 10, a l t h o u g h I shall also s a y s o m e t h i n g briefly a b o u t t h e matter shortly. T h e c o u r s e of t h e a r g u m e n t will p r o c e e d r o u g h l y a s f o l l o w s . In c h a p t e r s 2 a n d 3 I shall c o n s i d e r the e m p i r i c i s t s ' r e j e c t i o n of s u b s t a n t i v e a priori k n o w l e d g e , f o c u s i n g particularly o n their r e j e c t i o n o f p l a t o n i s m . In c h a p t e r 2 I shall c o n s i d e r t h e c a s e that can b e m a d e out in s u p p o r t of p l a t o n i s m . In c h a p t e r 3 I shall c o n s i d e r b o t h h o w a n e m p i r i c i s t m i g h t try to u n d e r m i n e t h a t c a s e a n d their positive r e a s o n s for t h i n k i n g p l a t o n i s m to b e f a l s e . T h i s will b e t h e m o s t t e c h n i c a l c h a p t e r of t h e b o o k , a n d r e a d e r s a r e a d v i s e d to t a k e it s l o w l y . M y c o n c l u s i o n will b e that t h e g r o u n d s for t h e e m p i r i c i s t r e j e c t i o n of s u b s t a n t i v e a priori k n o w l e d g e are indeed powerful. T h e n in c h a p t e r s 4 - 8 I shall c o n s i d e r t h e e m p i r i c i s t r e j e c t i o n of n a t i v i s m . In c h a p t e r 4 I shall d i s c u s s L o c k e ' s a r g u m e n t s a g a i n s t i n n a t e k n o w l e d g e a n d i n n a t e c o n c e p t s . In c h a p t e r 5 I shall c o n s i d e r w h e t h e r t h e v e r y idea o f i n n a t e k n o w l e d g e is i n c o h e r e n t , b y v i r t u e of o u r c o n c e p t i o n of w h a t k n o w l e d g e itself is. In c h a p t e r 6 I shall c o n s i d e r t h e c a s e p r o v i d e d b y c o n t e m p o r a r y cognitive science for innate information-bearing m e n t a l structures, concentrating o n C h o m s k y ' s a r g u m e n t s for a n innately structured l a n g u a g e faculty. In c h a p t e r 7 1 shall c o n s i d e r t h e c a s e for s a y i n g t h a t t h e r e are i n n a t e c o n c e p t s , c o n s i d e r i n g particularly t h e a r g u m e n t s of F o d o r . T h e n in c h a p t e r 8 I shall c o n s i d e r t h e c a s e for s a y i n g that w e p o s s e s s s u b s t a n t i v e i n n a t e k n o w l e d g e , in

16

Introduction

p a r t i c u l a r of t r u t h s c o n c e r n i n g o u r o w n p s y c h o l o g y . M y c o n c l u s i o n will b e that t h e e m p i r i c i s t c a s e a g a i n s t n a t i v i s m is l a m e n t a b l y w e a k , a n d that at least s o m e of o u r k n o w l e d g e a n d c o n c e p t s a r e very p r o b a b l y i n n a t e . G i v e n this s i t u a t i o n — w i t h o n e s t r a n d in classical e m p i r i c i s m e n d o r s e d a n d o n e r e j e c t e d — w e t h e n face t h e q u e s t i o n of t h e fate o f t h e m o v e m e n t a s a w h o l e . In particular, w e n e e d to k n o w w h e t h e r t h e denial of n a t i v i s m is truly an e s s e n t i a l p a r t of t h e e m p i r i c i s t p r o j e c t . In c h a p t e r s 9 a n d 10 I shall a r g u e that it is n o t . R a t h e r , the c o r e of e m p i r i c i s m c o n s i s t s in a certain sort of n a t u r a l i s m (distinct from that briefly c h a r a c t e r i z e d a b o v e ) . T h e main c o n c e r n is to insist that c l a i m s to k n o w l e d g e s h o u l d o n l y be e n d o r s e d w h e r e w e can b e g i n to g i v e an a c c o u n t , in t e r m s of natural p r o c e s s e s , of the m a n n e r in w h i c h that k n o w l e d g e m i g h t h a v e a r i s e n in u s . T h e r e a s o n w h y t h e early e m p i r i c i s t s r e j e c t e d n a t i v i s m , I shall a r g u e , is that the o n l y f o r m o f a c c o u n t available to t h e m at the t i m e , of h o w a belief or c o n c e p t m i g h t c o m e to be i n n a t e , w a s a n o n - n a t u r a l o n e , n a m e l y direct i n t e r v e n t i o n by G o d . But n o w , with t h e a d v e n t of e v o l u t i o n a r y t h e o r y , w e can r e m a i n t r u e to t h e e m p i r i c i s t p r o j e c t w h i l e at t h e same time embracing nativism. In t h e final t w o c h a p t e r s I shall e x p l o r e t h e c o n s e q u e n c e s of this r e s u l t for the p r o b l e m of s c e p t i c i s m , t r e a t i n g s e p a r a t e l y the p r o b l e m of i n d u c t i o n a n d the p r o b l e m of t h e e x t e r n a l w o r l d . H e r e I shall a r g u e that, g i v e n c o m m i t m e n t s to certain s o r t s of nativism, solutions to these p r o b l e m s m a y readily b e c o n s t r u c t e d . I n d e e d , it will turn o u t that n o t o n l y the classical e m p i r i c i s t s ' r e j e c t i o n of n a t i v i s m , b u t also their t e n d e n c y t o w a r d s s c e p t i c i s m or p h e n o m e n a l i s m , w e r e historical a c c i d e n t s . E a c h r e s u l t e d f r o m t h e scientific i g n o r a n c e of t h e t i m e , r a t h e r t h a n f r o m a n y e s s e n t i a l a s p e c t of t h e e m p i r i c i s t e n t e r p r i s e . T h e final p o s i t i o n will b e a n e m p i r i c i s m d e n u d e d of its o p p o s i t i o n to n a t i v i s m ( w h i l e still r e t a i n i n g the classic o p p o s i t i o n to s u b s t a n t i v e a priori k n o w l e d g e ) , e n d o r s i n g a r o b u s t r e a l i s m a b o u t o u r k n o w l e d g e of t h e p h y s i c a l w o r l d . T h i s p o s i t i o n , I a r g u e , is n o t o n l y distinctively e m p i r i c i s t , b u t c o r r e c t .

2 Knowledge out of Reason: Platonism IN this s e c o n d c h a p t e r I shall c o n s i d e r a r g u m e n t s s u p p o r t i n g o n e of t h e m a j o r f o r m s of r a t i o n a l i s m , n a m e l y p l a t o n i s m with r e s p e c t to the t r u t h s of m a t h e m a t i c s , logic, a n d c o n c e p t u a l analysis.

Rationalism a n d Platonism R a t i o n a l i s t s are u n i t e d in b e l i e v i n g that it is p o s s i b l e for u s to a c q u i r e s u b s t a n t i v e k n o w l e d g e of t h e w o r l d a priori. P l a t o n i s m is ( a l m o s t a l w a y s ) a f o r m of r a t i o n a l i s m , s i n c e p l a t o n i s t s b e l i e v e that w e m a y o b t a i n a priori k n o w l e d g e of a realm of a b s t r a c t o b j e c t s , i n c l u d i n g n u m b e r s a n d u n i v e r s a l s . T h i s k n o w l e d g e is g e n u i n e l y s u b s t a n t i v e , s i n c e s u c h o b j e c t s are h e l d to exist i n d e p e n d e n t l y of t h e h u m a n m i n d . But p l a t o n i s m is n o t t h e o n l y f o r m of r a t i o n a l i s m . M a n y rationalists h a v e also b e l i e v e d that w e c a n k n o w a priori o f the e x i s t e n c e a n d i m m o r t a l i t y of t h e s o u l , of t h e e x i s t e n c e of a n a l l - p o w e r f u l , g o o d G o d , a n d of t h e f r e e d o m of t h e will. I n d e e d , in L o c k e ' s o w n d a y m a n y b e l i e v e d that w e c o u l d k n o w a priori the b a s i c c o n s t i t u t i o n of t h e n a t u r a l world a r o u n d u s . T h i s w a s o n e form of the medieval-Aristotelian c o n c e p t i o n of s c i e n c e . It w a s b e l i e v e d that t h e v a r i o u s natural s c i e n c e s f o r m d e d u c t i v e s y s t e m s ( s o m e w h a t like g e o m e t r y ) , t h e a x i o m s of w h i c h a r e s e l f - e v i d e n t l y true as well as i n n a t e l y k n o w n . ( T h i s w a s t h e f o r m of r a t i o n a l i s m that L o c k e h i m s e l f w a s m o s t c o n c e r n e d to attack directly.) 1

W h i l e p l a t o n i s m is o n l y o n e f o r m of rationalist belief, it n e v e r t h e l e s s h o l d s a c e n t r a l p o s i t i o n in t h e d e b a t e w i t h Q u i n e a n d his f o l l o w e r s b e l i e v e t h a t s e t s a n d o t h e r a b s t r a c t o b j e c t s m a y b e k n o w n e m p i r i c a l l y , o n t h e b a s i s o f total s c i e n c e . 1

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Knowledge out of Reason

e m p i r i c i s m . T h i s is b e c a u s e logic a n d m a t h e m a t i c s r e p r e s e n t t h e o n l y e x a m p l e s of a priori k n o w a b l e t r u t h s t h a t a r e relatively u n c o n t r o v e r s i a l . A l m o s t e v e r y o n e ( w h e t h e r e m p i r i c i s t or r a t i o n alist) a g r e e s that it is true that 2 + 2 = 4 , a n d that w e m a y k n o w this a priori, by a p r o c e s s of r e a s o n i n g a l o n e . S o if it c o u l d b e s h o w n that this t r u t h is g e n u i n e l y s u b s t a n t i v e , it w o u l d follow that r a t i o n a l i s m is v i n d i c a t e d : it w o u l d follow that it is p o s s i b l e for u s to a c q u i r e s u b s t a n t i v e k n o w l e d g e t h r o u g h r e a s o n a l o n e . It w o u l d t h e n b e h a r d to s e e w h y t h e r e s h o u l d b e a n y o b j e c t i o n in p r i n c i p l e to the u s e of r e a s o n d i s c o v e r i n g for u s o t h e r s u b s t a n t ive t r u t h s , s u c h as t h e e x i s t e n c e of t h e s o u l or t h e f r e e d o m of t h e will. In c o n t r a s t , in all o t h e r d o m a i n s w h e r e rationalists h a v e s o u g h t s u b s t a n t i v e a priori k n o w l e d g e — f o r e x a m p l e , a t t e m p t ing to c o n s t r u c t p r o o f s of t h e e x i s t e n c e of t h e s o u l , or of t h e e x i s t e n c e of G o d — e m p i r i c i s t s h a v e b e l i e v e d (in m o s t c a s e s rightly) that they c o u l d d e t e c t e r r o r s in t h e r e a s o n i n g u s e d that were quite independent of the empiricist-rationalist debate. S u c h a r g u m e n t s t h u s d o n o t c o n s t i t u t e a p r o b l e m for e m p i r i c i s m , in the w a y that t h e t r u t h s of logic a n d m a t h e m a t i c s m a n i f e s t l y d o . N o r d o t h e y a m o u n t to v e r y p o w e r f u l e v i d e n c e of the truth of r a t i o n a l i s m . I t h e r e f o r e p r o p o s e to c o n c e n t r a t e u p o n p l a t o n i s m in this c h a p t e r . T h i s is n o t o n l y b e c a u s e of its crucial p o s i t i o n in t h e overall d e b a t e , b u t a l s o b e c a u s e this is t h e p o i n t at w h i c h t h e i s s u e s b e t w e e n e m p i r i c i s t s a n d rationalists c a n b e p r e s e n t e d in their s h a r p e s t f o c u s . In c h a p t e r 10 I shall r e t u r n a g a i n to c o n s i d e r r a t i o n a l i s t s ' c l a i m s to o t h e r f o r m s of s u b s t a n t i v e a priori k n o w l e d g e . P l a t o n i s t s m a i n t a i n that a l o n g s i d e t h e p h y s i c a l w o r l d t h e r e also exists a r e a l m of a b s t r a c t ( n o n - p h y s i c a l a n d c h a n g e l e s s ) entities, peopled by universals (such as greenness, friendship, a n d b e a u t y ) , a n d by m a t h e m a t i c a l o b j e c t s ( i n c l u d i n g n u m b e r s a n d g e o m e t r i c a l f i g u r e s ) . T h e y b e l i e v e that it is t h e s e e n t i t i e s that t h e p r o p o s i t i o n s of logic, m a t h e m a t i c s , a n d c o n c e p t u a l a n a l y s i s a r e about. T h e y h o l d t h a t t h e s e e n t i t i e s c o n s t i t u t e t h e s u b j e c t - m a t t e r of o u r logical a n d m a t h e m a t i c a l p r o p o s i t i o n s . P l a t o n i s t s also g e n e r a l l y b e l i e v e that a b s t r a c t e n t i t i e s h a v e a m o d e of e x i s t e n c e w h i c h is necessary, b e l i e v i n g that n u m b e r s , for e x a m p l e , exist at all t i m e s a n d in all c o n c e i v a b l e c i r c u m s t a n c e s (in all p o s s i b l e w o r l d s ) . T h e y b e l i e v e t h a t n o m a t t e r h o w d i s t a n t


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t h e p a s t or f u t u r e o n e c o n s i d e r s , a n d n o m a t t e r h o w d i f f e r e n t t h e n a t u r a l w o r l d m i g h t h a v e b e e n f r o m t h e w a y it actually is, it w o u l d still h a v e b e e n t h e c a s e that n u m b e r s exist, a n d e a c h n u m b e r w o u l d still h a v e h a d t h e v e r y s a m e m a t h e m a t i c a l properties. S o m e p l a t o n i s t s h a v e h e l d that a b s t r a c t e n t i t i e s h a v e a n e x i s t e n c e that is timeless r a t h e r t h a n n e c e s s a r y . T h e y h a v e h e l d that, s o far f r o m e x i s t i n g at all t i m e s in all p o s s i b l e w o r l d s , it makes no sense to say of a n a b s t r a c t o b j e c t that it e x i s t s at a p a r t i c u l a r t i m e , or at all t i m e s — j u s t as it m a k e s n o s e n s e to say of an a b s t r a c t o b j e c t that it e x i s t s in a particular p l a c e , or in all p l a c e s . But in m y v i e w this t h e s i s lacks intuitive plausibility. For s e n t e n c e s like ' T h e n u m b e r 7 a l w a y s h a s a n d a l w a y s will e x i s t ' j u s t d o n o t h a v e t h e o b v i o u s k i n d of s e n s e l e s s n e s s p o s s e s s e d by s u c h s e n t e n c e s as ' T h e n u m b e r 7 is e v e r y w h e r e ' . ( E v e r y o n e will c o n c e d e that a b s t r a c t o b j e c t s a r e spaceless.) O n t h e c o n t r a r y , s u c h s e n t e n c e s s e e m p e r f e c t l y intelligible, if n o t o b v i o u s l y t r u e . H o w e v e r , n o t h i n g of a n y g r e a t s i g n i f i c a n c e t u r n s on this i s s u e for o u r p r e s e n t p u r p o s e s . In w h a t f o l l o w s I shall c o n f i n e a t t e n t i o n to that v e r s i o n of p l a t o n i s m w h i c h c l a i m s n e c e s s a r y e x i s t e n c e for a b s t r a c t e n t i t i e s . F o r it is e a s i e r to e x p r e s s p l a t o n i s t d o c t r i n e s , a n d to p r e s e n t a r g u m e n t s in their s u p p o r t , if p l a t o n i c o b j e c t s a r e s u p p o s e d to h a v e n e c e s s a r y r a t h e r t h a n t i m e l e s s existence. W h e n it c o m e s to e x p l a i n i n g o u r k n o w l e d g e of a b s t r a c t e n t i t i e s , m a n y p l a t o n i s t s h a v e b e l i e v e d that w e p o s s e s s a s p e c i a l faculty of intellectual i n t u i t i o n , m o d e l l e d b y a n a l o g y w i t h s e n s e p e r c e p t i o n . T h e p u r p o s e of this faculty is to m a k e a v a i l a b l e to u s facts a b o u t t h e a b s t r a c t r e a l m , j u s t as o u r s e n s e s s e r v e to m a k e available to u s facts a b o u t o u r i m m e d i a t e p h y s i c a l e n v i r o n m e n t . T h e i d e a is that w h e n w e c o m e to b e l i e v e s i m p l e c o n c e p t u a l or m a t h e m a t i c a l t r u t h s , w e intuit a n a s p e c t of t h e a b s t r a c t r e a l m — w e ' s e e it w i t h o u r m i n d ' s e y e ' . S o t h e fact that t h e a b s t r a c t r e a l m c o n t a i n s t h e n u m b e r 7, w h i c h h a s t h e p r o p e r t y of b e i n g p r i m e , is to e x p l a i n m y belief that 7 is p r i m e in s o m e t h i n g like t h e m a n n e r in w h i c h t h e fact that t h e r e is a c u p o n t h e d e s k in front of m e e x p l a i n s m y p e r c e p t u a l b e l i e f that t h e r e is a c u p o n t h e d e s k . In b o t h c a s e s t h e state of affairs in q u e s t i o n is s u p p o s e d to e x e r t a n i n f l u e n c e u p o n m y m i n d , via faculties of intuition and perception respectively.


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D o e s this t h e n m e a n t h a t t h e belief that 7 is p r i m e is n o t really a priori? S h o u l d w e t h i n k of intellectual i n t u i t i o n as a w a y of a c q u i r i n g e x p e r i e n t i a l (empirical) k n o w l e d g e of t h e a b s t r a c t r e a l m ? I t h i n k n o t . T h e r e are t w o r e a s o n s for t h i s . T h e first is that, in c o n t r a s t with g e n u i n e s e n s e - e x p e r i e n c e , t h e r e a r e n o s e n s a t i o n s characteristic of a c q u i r i n g a n e w m a t h e m a t i c a l belief. W h e n I s e e that t h e r e is a c u p on t h e d e s k , m y e x p e r i e n c e h a s its o w n distinctive p h e n o m e n o l o g i c a l c h a r a c t e r . B u t w h e n I ' s e e ' that 7 is p r i m e , all that h a p p e n s is that I c o m e to h a v e a n e w belief. P h e n o m e n o l o g i c a l l y s p e a k i n g , it r e m a i n s t h e c a s e that the o n l y p r o c e s s i n v o l v e d in the a c q u i s i t i o n of n e w m a t h e m a t ical beliefs is t h o u g h t . T h e s e c o n d d i f f e r e n c e b e t w e e n intellectual intuition a n d g e n u i n e p e r c e p t i o n is that t h e s u p p o s e d faculty of intellectual intuition r e m a i n s a b a r e h y p o t h e s i s , lacking i n d e p e n d e n t c o n f i r m a t i o n . In c o n n e c t i o n w i t h g e n u i n e s e n s e - e x p e r i e n c e , in c o n t r a s t , w e h a v e w e l l - g r o u n d e d b e l i e f s a b o u t the s t r u c t u r e s , l o c a t i o n s , a n d m o d e s of o p e r a t i o n of t h e various s e n s e s . 2

W h a t a r e t h e m a i n a r g u m e n t s that c a n b e g i v e n in s u p p o r t of p l a t o n i s m ? I shall b e g i n by c o n s i d e r i n g t h e a r g u m e n t s for b e l i e v i n g that t h e r e a r e a b s t r a c t e n t i t i e s at all, t a k i n g t h e c a s e of n u m b e r s first (it is h e r e that the a r g u m e n t s are s t r o n g e s t ) . I shall t h e n d i s c u s s t h e e x i s t e n c e of u n i v e r s a l s . Finally, I shall c o n s i d e r the a r g u m e n t s for b e l i e v i n g , n o t o n l y that t h e r e a r e a b s t r a c t e n t i t i e s , b u t that s u c h e n t i t i e s h a v e m i n d - i n d e p e n d e n t , i n d e e d necessary, existence.

N u m b e r s as Objects A p o w e r f u l c a s e c a n b e m a d e for s a y i n g that n u m b e r s exist as abstract i n d i v i d u a l o b j e c t s . It h a s b e e n p r e s e n t e d m o s t clearly b y t h e n i n e t e e n t h - c e n t u r y p l a t o n i s t a n d logician, G o t t l o b F r e g e , t h o u g h m a n y of t h e p o i n t s w e r e implicit in t h e w r i t i n g s of P l a t o . T h e a r g u m e n t b e g i n s b y n o t i n g that in m u c h of o u r 3

F o r f u r t h e r d i s c u s s i o n o f t h e p r o p e r c h a r a c t e r i z a t i o n of t h e s e n s e s , a n d of t h e w a y in w h i c h w e m a y k n o w h o w m a n y s e n s e s t h e r e a r e , s e e t h e p a p e r s e n t i t l e d ' C a t e g o r i s i n g t h e S e n s e s ' b y M a r k L e o n a n d N o r t o n N e l k i n , in Mind and Language, 1988 and 1990 respectively. S e e F r e g e ' s little m a s t e r p i e c e The Foundations of Arithmetic 1884; (trans. J. A u s t i n , O x f o r d : B l a c k w e l l , 1 9 5 0 ) , f r o m w h i c h m u c h of w h a t f o l l o w s in this s e c t i o n is d e r i v e d . S e e a l s o P l a t o ' s Republic, b k . vi. 2

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t h o u g h t a n d s p e e c h w e treat n u m b e r s as i n d i v i d u a l o b j e c t s . I n d e e d , in m o s t of their o c c u r r e n c e s in s e n t e n c e s n u m e r a l s ( n u m b e r - w o r d s ) a p p e a r to f u n c t i o n j u s t like p r o p e r n a m e s . It is w o r t h s p e l l i n g this o u t in s o m e detail, d i s t i n g u i s h i n g six d i f f e r e n t r e s p e c t s in w h i c h l a n g u a g e s e e m s to treat n u m b e r s as individual objects. First, w e p r e d i c a t e t h i n g s of n u m b e r s , j u s t as w e p r e d i c a t e t h i n g s of p h y s i c a l o b j e c t s . C o m p a r e t h e s e n t e n c e ' D a v i d is a small m a n ' w i t h t h e s e n t e n c e s '7 is a small n u m b e r ' , or '7 is p r i m e ' . J u s t a s in t h e first s e n t e n c e t h e u s e of t h e n a m e ' D a v i d ' s e r v e s to refer to a particular h u m a n , of w h o m w e t h e n p r e d i c a t e t h e p r o p e r t y of b e i n g s m a l l , s o too in the o t h e r s e n t e n c e s it a p p e a r s t h a t t h e n u m e r a l '7' is referring to a n i n d i v i d u a l o b j e c t , of w h i c h w e t h e n p r e d i c a t e t h e p r o p e r t y of b e i n g s m a l l , or t h e p r o p e r t y of b e i n g p r i m e . In s h o r t : t h e s e n t e n c e '7 is p r i m e ' is of s u b j e c t - p r e d i c a t e f o r m , w i t h t h e w o r d '7' s e r v i n g to i n t r o d u c e its s u b j e c t , j u s t a s a p r o p e r n a m e d o e s . S e c o n d l y , n u m b e r s can b e referred to by m e a n s of d e f i n i t e d e s c r i p t i o n s ( p h r a s e s of t h e f o r m ' t h e s u c h - a n d - s u c h ' ) , w h i c h a p p a r e n t l y s e r v e to p i c k o u t o n e i n d i v i d u a l t h i n g f r o m o t h e r s . T h u s c o m p a r e t h e t w o s e n t e n c e s ' T h e tallest living p e r s o n is t h e o l d e s t ' a n d T h e s u c c e s s o r of 6 is p r i m e ' . In the first s e n t e n c e t h e d e f i n i t e d e s c r i p t i o n ' T h e tallest living p e r s o n ' s e r v e s to pick o u t a n d d i s t i n g u i s h o n e f r o m t h e rest of u s ( e v e n if w e d o n o t k n o w w h o m ) , w h o is t h e n c l a i m e d to b e t h e o l d e s t . Similarly in t h e s e c o n d s e n t e n c e , t h e p h r a s e ' T h e s u c c e s s o r of 6' s e e m s to pick out a n d r e f e r to a p a r t i c u l a r n u m b e r (in fact t h e n u m b e r 7 ) , w h i c h is t h e n said t o b e p r i m e . T h i r d l y , w e q u a n t i f y o v e r n u m b e r s ( m a k i n g ' s o m e ' a n d 'all' s t a t e m e n t s a b o u t t h e m ) . T h i s s u g g e s t s that t h e y f o r m a d o m a i n of i n d i v i d u a l t h i n g s , j u s t a s p e o p l e f o r m a d o m a i n of i n d i v i d u a l t h i n g s . T h u s w e m a y s a y ' S o m e n u m b e r b e t w e e n 6 a n d 10 is p r i m e ' , j u s t as w e m i g h t s a y ' S o m e p e r s o n in t h e r o o m h a s fair h a i r ' . T h e m o s t n a t u r a l w a y to u n d e r s t a n d t h e t r u t h - c o n d i t i o n s of s u c h s e n t e n c e s is t h a t t h e y a r e true if a n d o n l y if t h e r e is s o m e i n d i v i d u a l — n a m e a b l e — t h i n g in t h e d o m a i n h a v i n g t h e p r o p erty in q u e s t i o n . T h e n it s e e m s that n u m b e r s , like p e o p l e , m u s t be individual nameable things. F o u r t h l y , w e take s t a t e m e n t s a b o u t i n d i v i d u a l n u m b e r s to imply existence-statements, just as w e do statements about p e o p l e . T h u s , in t h e s a m e w a y t h a t ' D a v i d is i n t h e r o o m '

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i m p l i e s ' S o m e o n e is in t h e r o o m ' (by v i r t u e of o u r i n t e n t i o n that t h e n a m e ' D a v i d ' s h o u l d refer to a n e x i s t i n g i n d i v i d u a l ) , s o t o o d o e s '7 is p r i m e ' i m p l y ' S o m e n u m b e r is p r i m e ' . T h i s s u g g e s t s that w e m u s t b e i n t e n d i n g t h e n u m e r a l '7' to refer to a n e x i s t i n g individual t h i n g , in s u c h a w a y t h a t s t a t e m e n t s i n v o l v i n g that n u m e r a l c a n o n l y be true if the i n t e n d e d r e f e r e n t really d o e s exist. Fifthly, w e m a k e s t a t e m e n t s of i d e n t i t y c o n c e r n i n g n u m b e r s , j u s t as w e d o c o n c e r n i n g i n d i v i d u a l p h y s i c a l o b j e c t s . T h u s just as w e m i g h t s a y ' T h a t c h e r is n o n e o t h e r t h a n M a r g a r e t ' (or ' T h a t c h e r a n d M a r g a r e t a r e o n e a n d t h e s a m e p e r s o n ' ) , s o too w e m a y say '2 + 2 a n d 4 a r e o n e a n d t h e s a m e n u m b e r ' , o r , m o r e s i m p l y , '2 + 2 = 4 ' . (In o r d e r to p r o v i d e a c o n t e x t for t h e first of t h e s e s t a t e m e n t s , s u p p o s e y o u k n o w that M r s T h a t c h e r w a s t h e British P r i m e M i n i s t e r in 1989 w i t h o u t k n o w i n g w h a t s h e l o o k s like, a n d a r e t h e n i n t r o d u c e d to s o m e o n e at a r e c e p t i o n a s ' M a r g a r e t ' w i t h o u t realizing that s h e w a s t h e 1 9 8 9 P r i m e M i n i s t e r , o n l y later d i s c o v e r i n g that t h e y a r e o n e a n d t h e s a m e p e r s o n . ) In this r e s p e c t , t o o , l a n g u a g e treats n u m b e r s a s individual o b j e c t s , w h i c h c a n b e e i t h e r identical o r d i s t i n c t f r o m one another. F i n a l l y , it is a g e n e r a l t r u t h a b o u t i n d i v i d u a l o b j e c t s t h a t t h e y do not have contradictories, whereas properties do. Nor do n u m b e r s h a v e c o n t r a d i c t o r i e s ( w h i c h are also n u m b e r s ) . All p r o p e r t i e s h a v e c o n t r a d i c t o r i e s , in t h e s e n s e that for a n y p r o p e r t y , t h e r e is a n o t h e r p r o p e r t y t h a t is true of s o m e t h i n g if a n d o n l y if t h e first is n o t t r u e of it. F o r a n y p r o p e r t y F , t h e r e is t h e p r o p e r t y of b e i n g n o t F . T h e c o r r e s p o n d i n g p r i n c i p l e d o e s not h o l d for o b j e c t s . It is n o t t h e c a s e t h a t for a n y o b j e c t t h e r e is a n o t h e r o b j e c t that p o s s e s s e s a p r o p e r t y if a n d o n l y if that p r o p e r t y is n o t p o s s e s s e d b y t h e first o b j e c t . R a t h e r , a l m o s t a n y t w o o b j e c t s will h a v e something in c o m m o n . S i m i l a r l y , a n y t w o n u m b e r s will h a v e s o m e t h i n g in c o m m o n . F o r e x a m p l e , b o t h 7 a n d 6 4 0 a r e larger t h a n 6. W e certainly c a n n o t g u a r a n t e e that for a n y n u m b e r , t h e r e is a n o t h e r n u m b e r t h a t l a c k s j u s t t h e properties the former p o s s e s s e s , a n d vice versa. 4

If n u m b e r s a r e t r e a t e d a s p r o p e r t i e s of s e t s , s o t h a t , f o r e x a m p l e , t h e n u m b e r 7 is i d e n t i f i e d w i t h t h e p r o p e r t y o f h a v i n g 7 m e m b e r s , t h e n t h e r e will a l s o b e t h e p r o p e r t y o f not h a v i n g 7 m e m b e r s . B u t this will n o t itself b e a n u m b e r . 4


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W h i l e t h e r e a r e m a n y r e s p e c t s in w h i c h o u r l a n g u a g e t r e a t s n u m b e r s as o b j e c t s , w i t h n u m e r a l s f u n c t i o n i n g in s e n t e n c e s j u s t like p r o p e r n a m e s , this is n o t u n i v e r s a l l y t h e c a s e . In s t a t e m e n t s of n u m b e r s u c h as ' J u p i t e r h a s 4 m o o n s ' t h e n u m e r a l ' 4 ' s e e m s r a t h e r to o c c u r as an a d j e c t i v e . It a p p e a r s to b e q u a l i f y i n g t h e n o u n ' m o o n s ' , in s o m e t h i n g like t h e w a y that t h e a d j e c t i v e ' l a r g e ' d o e s in t h e s e n t e n c e 'Jupiter h a s large m o o n s ' . Y e t t h e r e is a d i f f e r e n c e . F o r f r o m ' J u p i t e r h a s large m o o n s ' w e m a y infer ' E a c h of t h e m o o n s of J u p i t e r is l a r g e ' ; w h e r e a s from ' J u p i t e r h a s 4 m o o n s ' w e certainly c a n n o t infer ' E a c h of the m o o n s of J u p i t e r is 4 ' . S o if ' 4 ' o c c u r s h e r e as an a d j e c t i v e , it is by n o m e a n s an ordinary adjective. In fact t h e q u a s i - a d j e c t i v a l u s e of n u m e r a l s c a n easily be r e n d e r e d c o n s i s t e n t w i t h their o t h e r w i s e n a m e l i k e u s e , if w e notice that t h e s t a t e m e n t s of n u m b e r in w h i c h t h e y figure can b e r e w r i t t e n as i d e n t i t i e s w i t h o u t a n y l o s s of c o n t e n t . T h e s e n t e n c e ' J u p i t e r h a s 4 m o o n s ' s a y s the s a m e as ' T h e n u m b e r of m o o n s of J u p i t e r is n o n e o t h e r t h a n 4 ' , in w h i c h ' 4 ' d o e s explicitly o c c u r in t h e role of a p r o p e r n a m e . ( N o t e , in c o n t r a s t , that w e c a n n o t easily say ' T h e size of t h e m o o n s of J u p i t e r is n o n e o t h e r t h a n large'. This seems nonsensical.) S i n c e w e u s e n u m e r a l s in t h e m a n n e r of p r o p e r n a m e s , o u r l a n g u a g e treats n u m b e r s t h e m s e l v e s as individual o b j e c t s . T h e n if a n y s t a t e m e n t s of a r i t h m e t i c are t r u e , it s e e m s that n u m b e r s m u s t really exist. F o r c o m p a r e : t h e s t a t e m e n t ' D a v i d is a small m a n ' c a n n o t b e true u n l e s s the n a m e ' D a v i d ' d o e s s u c c e e d in referring to s o m e o n e , that is, u n l e s s t h e p e r s o n D a v i d really d o e s exist. Similarly, t h e n , '7 is p r i m e ' c a n n o t b e true u n l e s s t h e n u m b e r 7 really e x i s t s . F o r this is a s t a t e m e n t a b o u t t h e i n t e n d e d r e f e r e n t of the n a m e ' 7 ' , j u s t as ' D a v i d is a small m a n ' is a statement about the intended referent of the n a m e 'David'. W e t h e n a p p a r e n t l y face a stark c h o i c e : e i t h e r to a c c e p t that n u m b e r s a r e g e n u i n e l y e x i s t i n g o b j e c t s , or to r e j e c t all s t a t e m e n t s o f a r i t h m e t i c as f a l s e . If the latter is t o o h i g h a price to p a y , t h e n w e m u s t a c c e p t that n u m b e r s exist as i n d i v i d u a l things. F r o m t h e fact that n u m b e r s are i n d i v i d u a l o b j e c t s , it d o e s n o t i m m e d i a t e l y follow that t h e y are abstract ( n o n - p h y s i c a l a n d c h a n g e l e s s ) o b j e c t s . B u t this f u r t h e r t h e s i s m a y b e e s t a b l i s h e d w i t h v e r y little a d d i t i o n a l a r g u m e n t . F o r it is o b v i o u s that


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n u m b e r s are n o t p h y s i c a l t h i n g s , like t a b l e s a n d c h a i r s . T h u s it really d o e s s e e m to b e n o n s e n s i c a l to a s k where t h e n u m b e r 7 m i g h t b e , as w e n o t e d a b o v e . E v e n t h o s e w h o m a i n t a i n that n u m b e r s are really s e t s of s e t s of t h i n g s (for e x a m p l e , i d e n t i f y ing t h e n u m b e r 3 w i t h t h e set of all trios of t h i n g s ) a r e f o r c e d to c o n c e d e t h i s . F o r s e t s of physical t h i n g s (let a l o n e s e t s of s u c h sets) a r e n o t t h e m s e l v e s physical t h i n g s . E v e n if e a c h fair-haired p e r s o n is p h y s i c a l , t h e set of s u c h p e o p l e is n o t . 5

M o r e o v e r , s i n c e t h e t r u t h s of a r i t h m e t i c a r e n e c e s s a r y , h o l d i n g with r e s p e c t to all t i m e s a n d all p o s s i b l e w o r l d s , it is clear that n u m b e r s m u s t b e c h a n g e l e s s t h i n g s . W e certainly h a v e n o u s e for t h e idea that t h e r e a r e c i r c u m s t a n c e s in w h i c h 7 w o u l d n o t h a v e b e e n p r i m e , n o r for t h e idea that at s o m e f u t u r e t i m e it m i g h t c e a s e to b e s o . W h a t h a s to b e a c k n o w l e d g e d , h o w e v e r , is that n u m b e r s c a n u n d e r g o c h a n g e in their relational p r o p e r t i e s ; that is to s a y , in t h e r e l a t i o n s in w h i c h t h e y s t a n d to c h a n g i n g p h y s i c a l t h i n g s . For s u p p o s e J u p i t e r l o s e s o n e of its m o o n s . T h e n at o n e t i m e t h e n u m b e r of its m o o n s is 4 a n d at a later t i m e it is 3 . B u t this is b e s t v i e w e d a s a c h a n g e in t h e r e l a t i o n s o b t a i n i n g b e t w e e n n u m b e r s a n d t h e t h i n g s in t h e w o r l d s a t i s f y i n g a certain d e s c r i p t i o n , r a t h e r t h a n a c h a n g e in the numbers themselves.

A r e a n y Mathematical Statements True? A t this p o i n t w e s h o u l d c o n s i d e r h o w p l a u s i b l e it w o u l d b e to try r e s i s t i n g the a b o v e a r g u m e n t for p l a t o n i s m a b o u t n u m b e r s by r e j e c t i n g all m a t h e m a t i c a l s t a t e m e n t s a s false. T h i s is t h e option defended by Hartry Field. H e agrees with the platonist i n t e r p r e t a t i o n of t h e s u b j e c t - m a t t e r of a r i t h m e t i c , a c c e p t i n g that '2 + 2 = 4' p u r p o r t s to state a fact a b o u t a b s t r a c t o b j e c t s . B u t b e c a u s e h e d o e s n o t a c c e p t t h e e x i s t e n c e of s u c h o b j e c t s , h e d o e s n o t a c c e p t that a r i t h m e t i c c o n t a i n s a n y t r u t h s — j u s t a s s o m e o n e w h o d e n i e s t h e e x i s t e n c e of D a v i d w o u l d d e n y t h a t ' D a v i d is a s m a l l m a n ' c a n e x p r e s s a t r u t h . Y e t h e h o p e s to e x p l a i n h o w a r i t h m e t i c c a n b e u s e f u l in its a p p l i c a t i o n s , in t e r m s of its consistency. In F i e l d ' s v i e w m a t h e m a t i c a l s t a t e m e n t s m i g h t h a v e F o r a contrary view, see P e n e l o p e M a d d y 'Physicalistic Platonism', A . I r v i n e ( e d . ) , Physicalism in Mathematics ( D o r d r e c h t : K l u w e r , 1 9 9 0 ) . 5

in


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b e e n true (had there existed any n u m b e r s ) , although they do n o t h a p p e n to b e s o ; a n d this is c l a i m e d to b e sufficient to e x p l a i n t h e practical u s e f u l n e s s of s u c h s t a t e m e n t s . A n initial o b j e c t i o n to Field is that his position c a n n o t b e a d e q u a t e l y m o t i v a t e d . T h i s is b e c a u s e t h e m a i n difficulty w i t h p l a t o n i s m , as w e shall s e e in c h a p t e r 3 , is that it c a n n o t p r o v i d e a n a c c e p t a b l e e x p l a n a t i o n of o u r k n o w l e d g e of m a t h e m a t i c s . T h u s in o r d e r to a r g u e that t h e p l a t o n i s t i n t e r p r e t a t i o n of m a t h e m a t i c s is false, w e shall s u p p o s e that m a t h e m a t i c s itself c o n s i s t s largely of t r u t h s , a n d i n d e e d is largely k n o w n to d o s o . S u c h an a r g u m e n t c a n n o t b e p u r s u e d by t h o s e , s u c h as Field, w h o w i s h to d e n y that m a t h e m a t i c s c o n s i s t s of t r u t h s . F i e l d ' s a t t e m p t to d e n y p l a t o n i s m by r e j e c t i n g all m a t h e m a t i c a l statem e n t s a s false w o u l d t h e n a p p e a r to b e s e l f - d e f e a t i n g . In fact Field c a n reply to this o b j e c t i o n . H i s v i e w is that o u r t h e o r y of t h e w o r l d — o u r total s c i e n c e — i s a b e t t e r t h e o r y if it e x c l u d e s p l a t o n i c o b j e c t s t h a n if it i n c l u d e s t h e m . A n d o n e of t h e m a i n r e a s o n s w h y belief in p l a t o n i c o b j e c t s w o u l d m a k e o u r overall t h e o r y w o r s e is that w e s h o u l d be left i n c a p a b l e o f e x p l a i n i n g h o w w e c o u l d h a v e k n o w l e d g e of t h o s e o b j e c t s . S o the a r g u m e n t a g a i n s t p l a t o n i s m , that it c a n n o t a d e q u a t e l y e x p l a i n h o w w e c o u l d h a v e k n o w l e d g e of m a t h e m a t i c s , c a n b e p r e s e n t e d w i t h o u t p r e s u p p o s i n g that a n y of o u r m a t h e m a t i c a l s t a t e m e n t s are t r u e . O n t h e c o n t r a r y , t h e r e a s o n w h y o u r t h e o r y of t h e w o r l d is b e t t e r for d e n y i n g that a n y m a t h e m a t i c a l s t a t e m e n t s a r e true is that w e c o u l d n o t e x p l a i n h o w w e c o u l d h a v e k n o w l e d g e of t h e m if t h e y w e r e . H o w e v e r , it is clear that F i e l d ' s s t r a t e g y for r e j e c t i n g p l a t o n i s m is o n e of very h i g h risk. For it n e e d s to b e s h o w n that a s c i e n c e w i t h o u t a n y m a t h e m a t i c a l t r u t h s is a b e t t e r total t h e o r y t h a n a s c i e n c e that i n c l u d e s s u c h t r u t h s . T o b e g i n w i t h , it is a m a t t e r of c o n s i d e r a b l e t e c h n i c a l c o m p l e x i t y to s h o w that s c i e n c e can b e p r e s e n t e d in s u c h a w a y as n o t to p r e s u p p o s e that a n y m a t h e m a t i c a l s t a t e m e n t s a r e t r u e . B u t e v e n t h e n , F i e l d ' s task is n o t c o m p l e t e . F o r e x p l a n a t o r y c o m p l e t e n e s s is o n l y o n e g o o d m a k i n g f e a t u r e of a t h e o r y . A n o t h e r is simplicity. S o if, a s s e e m s likely, scientific t h e o r i e s will b e m o r e c o m p l e x w h e n r e f o r m u lated s o as n o t to p r e s u p p o s e m a t h e m a t i c a l t r u t h , it will still n o t b e s e t t l e d that w e s h o u l d r e j e c t m a t h e m a t i c s as false. It m a y b e 6

6

S e e e . g . t h e p a p e r b y A . U r q u h a r t in I r v i n e , Physicalism

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that t h e b e s t overall o p t i o n will p r o v e to b e t h e p l a t o n i s t o n e , e v e n a c c e p t i n g that w e c a n n o t t h e n e x p l a i n t h e g e n e s i s of mathematical knowledge. P e r h a p s t h e m a i n o b j e c t i o n to F i e l d ' s p o s i t i o n , t h o u g h , is s i m p l y that it is h u g e l y c o u n t e r - i n t u i t i v e . It is v e r y h a r d i n d e e d to i n d u c e o n e s e l f to b e l i e v e that '2 + 2 = 4 ' m i g h t in fact b e f a l s e . A s a result, the p o s i t i o n c o n t a i n s a crucial dialectical w e a k n e s s . T h i s is b e c a u s e o u r p r e - t h e o r e t i c a l belief in t h e t r u t h s of m a t h e m a t i c s is m u c h m o r e firmly g r o u n d e d t h a n a n y m e r e l y philosophical a r g u m e n t for t h e p l a t o n i s t i n t e r p r e t a t i o n of the s u b j e c t - m a t t e r of t h o s e t r u t h s , s u c h as w a s s k e t c h e d in t h e p r e v i o u s s e c t i o n . S i n c e it r e q u i r e s an a r g u m e n t to c o n v i n c e u s that '2 + 2 = 4 ' is really a b o u t a b s t r a c t o b j e c t s , it will a l w a y s be m o r e r e a s o n a b l e for u s to think that s o m e t h i n g h a s g o n e a m i s s w i t h t h e p h i l o s o p h e r ' s a r g u m e n t t h a n to g i v e u p o u r m a t h e matical b e l i e f s . Field also faces a related p r o b l e m . For m a t h e m a t i c s is v e r y n a t u r a l l y taken to c o n s i s t of s t a t e m e n t s that, if t r u e , a r e t r u e n e c e s s a r i l y — h o l d i n g g o o d w i t h r e s p e c t to all p o s s i b l e w o r l d s . B u t t h e n if t h o s e s t a t e m e n t s a r e f a l s e , t h e y will b e n e c e s s a r i l y f a l s e — w h i c h conflicts w i t h F i e l d ' s claim that t h e y are c o n s i s t e n t (true w i t h r e s p e c t t o s o m e p o s s i b l e w o r l d ) . In fact it is a l m o s t equally h a r d to s e e h o w '2 + 2 = 4 ' m i g h t b e c o n t i n g e n t (true of s o m e w o r l d s b u t n o t o t h e r s ) as it is to s e e h o w it m i g h t b e false. N o w t h e o b j e c t i o n h e r e is n o t that if Field w e r e right, it w o u l d t h e n b e w h o l l y i n e x p l i c a b l e w h y t h e r e s h o u l d h a p p e n to be n o a b s t r a c t o b j e c t s . F o r Field m a y r e p l y that t h e n o n - e x i s t e n c e of n u m b e r s is a b r u t e c o n t i n g e n c y , c o m p a r a b l e in s t a t u s to t h e c l a i m that t h e r e a r e n o p h y s i c a l o b j e c t s , m a d e b y t h o s e w h o h a v e b e c o m e c o n v i n c e d of t h e n o n - e x i s t e n c e of m a t t e r . (It is o b v i o u s that s u c h a p e r s o n c a n n o t e x p l a i n why t h e r e are n o p h y s i c a l o b j e c t s , e x c e p t p e r h a p s t h e o l o g i c a l l y , by s a y i n g that G o d failed to c r e a t e a n y . W h y t h e n s h o u l d Field b e u n d e r a n y obligation to explain w h y there h a p p e n to b e n o n u m b e r s , other t h a n b y s a y i n g that G o d n e v e r m a d e a n y ? ) R a t h e r , t h e o b j e c t i o n parallels t h e o n e m a d e a b o v e . It is that o u r p r e - t h e o r e t i c a l c o n v i c t i o n that m a t h e m a t i c a l s t a t e m e n t s a r e n e c e s s a r y (as 7

F o r p u r s u i t o f t h i s line o f o b j e c t i o n t o F i e l d , s e e B o b H a l e , Abstract Objects ( O x f o r d : B l a c k w e l l , 1 9 8 7 ) , c h . 5, a s w e l l a s h i s ' N o m i n a l i s m ' in I r v i n e , Physicalism in Mathematics. 7


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o p p o s e d to c o n t i n g e n t ) is likely to b e m o r e firmly g r o u n d e d t h a n a n y p h i l o s o p h i c a l a r g u m e n t for a p l a t o n i s t i n t e r p r e t a t i o n of the s u b j e c t - m a t t e r of m a t h e m a t i c s . F i e l d ' s p o s i t i o n w o u l d s e e m to b e o n e of last resort for a n e m p i r i c i s t . I n d e e d , it is s o b a r e l y b e l i e v a b l e that if it w e r e t h e only o p t i o n a v a i l a b l e , t h e n this m i g h t b e a p o w e r f u l r e a s o n for e m b r a c i n g r a t i o n a l i s m . B u t in fact t h e r e are o t h e r possibilities o p e n to u s , a s w e shall s e e in t h e n e x t c h a p t e r . T h e c o n c l u s i o n t h u s far is that t h e e x i s t e n c e of n u m b e r s as abstract i n d i v i d u a l o b j e c t s c a n at least be s u p p o r t e d b y p o w e r f u l a r g u m e n t s , if n o t p r o v e d o u t r i g h t . At this p o i n t it a p p e a r s that a n e m p i r i c i s t w h o w i s h e s to o p p o s e p l a t o n i s m f a c e s a f o r m i d a b l e task.

The Existence of Universals T h e c a s e for b e l i e v i n g in a b s t r a c t u n i v e r s a l s h a s to b e m a d e s o m e w h a t d i f f e r e n t l y . F o r u n i v e r s a l s a r e s u p p o s e d to b e w h a t t h e p r e d i c a t i v e e x p r e s s i o n s o f n a t u r a l l a n g u a g e ( s u c h as ' w i s e ' or ' s m a l l ' ) refer to. A n d w e c a n n o t claim that s u c h e x p r e s s i o n s f u n c t i o n in s e n t e n c e s a s p r o p e r n a m e s (as w e c l a i m e d a b o v e t h a t numerals do) without destroying altogether the distinction b e t w e e n n a m e a n d p r e d i c a t e . It is true that m o s t p r e d i c a t e s a d m i t of n o m i n a l i z a t i o n s , w h i c h c a n t h e n figure in t h e s u b j e c t p o s i t i o n in a s e n t e n c e . T h u s , as well a s s e n t e n c e s like ' D a v i d is w i s e ' w e h a v e s e n t e n c e s s u c h a s ' W i s d o m is h a r d to a c q u i r e ' . B u t it is d o u b t f u l w h e t h e r a n y t h i n g of m u c h s i g n i f i c a n c e d e p e n d s o n t h i s . F o r it is g e n e r a l l y e a s y to s e e h o w t h e c o n t e n t of s e n t e n c e s c o n t a i n i n g s u c h n o m i n a l i z a t i o n s m a y b e e x p r e s s e d w i t h o u t loss b y s e n t e n c e s c o n t a i n i n g o n l y t h e c o r r e s p o n d i n g p r e d i c a t e . T h u s w h a t ' W i s d o m is h a r d to a c q u i r e ' really s a y s is that it is h a r d to b e c o m e w i s e . W h a t d o e s s e e m to r e q u i r e u s to r e c o g n i z e t h e e x i s t e n c e of u n i v e r s a l s is t h i s . W e a c c e p t e x i s t e n c e - c l a i m s that are n o t c l a i m s a b o u t t h e e x i s t e n c e of i n d i v i d u a l o b j e c t s (as is ' T h e r e is s o m e t h i n g t h a t is h u m a n ' ) , b u t a r e r a t h e r c l a i m s a b o u t t h e e x i s t e n c e of t h e p r o p e r t i e s t h o s e o b j e c t s p o s s e s s . T h u s c o n s i d e r t h e s e n t e n c e ' T h e r e is ( t h e r e exists) s o m e t h i n g that w e all a r e ( n a m e l y h u m a n ) ' . T h i s s u r e l y e x p r e s s e s a t r u t h . It s e e m s u n d e n i a b l e that t h e r e is s o m e t h i n g c o m m o n to u s all. In w h i c h

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c a s e it a p p e a r s that w e m u s t n o t o n l y a c c e p t t h e e x i s t e n c e of i n d i v i d u a l h u m a n s , b u t also of w h a t t h e y h a v e in c o m m o n — t h e u n i v e r s a l feature h u m a n n e s s . It is also true that t h e r e is ( t h e r e exists) s o m e t h i n g that g r a s s a n d l e a v e s h a v e in c o m m o n , n a m e l y g r e e n n e s s ; a n d s o o n . If w e a c c e p t s u c h t r u t h s , w e a p p e a r to b e a c c e p t i n g t h e e x i s t e n c e of u n i v e r s a l s . F r o m t h e fact that u n i v e r s a l s exist, it d o e s n o t i m m e d i a t e l y follow that t h e y a r e a b s t r a c t . N o t h i n g h a s a s y e t r u l e d o u t t h e idea that t h e y m a y r a t h e r b e i m m a n e n t in the p h y s i c a l w o r l d (as A r i s t o t l e m a i n t a i n e d ) . T h u s it m a y b e that u n i v e r s a l s s u c h a s g r e e n n e s s a r e , in part, physically p r e s e n t in t h e i n d i v i d u a l t h i n g s that i n s t a n t i a t e t h e m (that is, in t h e individual l e a v e s a n d b l a d e s of g r a s s that s h a r e t h e p r o p e r t y of b e i n g g r e e n ) . T h i s sort of v i e w h a s b e e n d e f e n d e d r e c e n t l y b y David A r m s t r o n g . H e a r g u e s that w e n e e d to p o s t u l a t e identical n a t u r e s in t h i n g s ( i m m a n e n t u n i v e r s a l s ) if w e a r e to g i v e an a d e q u a t e e x p l a n a t i o n of t h e fact that d i f f e r e n t t h i n g s c a n s h a r e similar c a u s a l p o w e r s , a n d of w h a t l a w s of n a t u r e a r e . H e t h i n k s that t h e b e s t e x p l a n a t i o n for t h e fact that all w a t e r b e h a v e s similarly in similar c i r c u m s t a n c e s — f r e e z i n g at z e r o c e n t i g r a d e , d i s s o l v i n g s u g a r , a n d s o o n — i s t h a t all w a t e r s h a r e s an identical i n n e r c o n s t i t u tion that n e c e s s i t a t e s that it b e h a v e a s it d o e s . T h i s i n n e r c o n s t i t u t i o n is a r e p e a t a b l e feature of the w o r l d , b e i n g i d e n t i c ally p r e s e n t in m a n y d i f f e r e n t i t e m s of w a t e r , a n d is h e n c e a u n i v e r s a l . But it is, on this v i e w , a u n i v e r s a l that is present in the p h y s i c a l i t e m s that i n s t a n t i a t e it. 8

W h a t a p p a r e n t l y f o r c e s u s to a c c e p t t h e a b s t r a c t n e s s of u n i v e r s a l s is that w e a c c e p t e x i s t e n c e - c l a i m s w i t h r e s p e c t to t h e m e v e n w h e n t h e y a r e not i n s t a n t i a t e d in t h e p h y s i c a l w o r l d . F o r e x a m p l e , it a p p e a r s to b e t r u e that t h e r e is ( t h e r e exists) s o m e t h i n g that nothing is ( n a m e l y , a u n i c o r n , or a d r a g o n ) . If this is a c c e p t e d , t h e n it s e e m s to f o l l o w that u n i v e r s a l s , in e x i s t i n g i n d e p e n d e n t l y of their i n s t a n c e s ( w h e r e t h e y h a v e i n s t a n c e s ) , are n o t p h y s i c a l l y p r e s e n t in t h e n a t u r a l w o r l d . T h e i r c h a n g e l e s s n e s s m a y t h e n b e e s t a b l i s h e d u s i n g similar c o n s i d e r a tions to t h o s e d e p l o y e d in t h e c a s e o f n u m b e r s . F o r w e h a v e n o u s e for t h e idea t h a t t h e u n i v e r s a l s d r a g o n n e s s or g r e e n n e s s S e e h i s b o o k s Universals and Scientific Realism U n i v e r s i t y P r e s s , 1 9 7 8 ) a n d What is a Law of Nature? University Press, 1983). 8

(Cambridge: (Cambridge:

Cambridge Cambridge


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t h e m s e l v e s u n d e r g o c h a n g e . A l t h o u g h a w i t h e r i n g b l a d e of grass is at o n e t i m e g r e e n a n d at a l a t e r t i m e n o t , this w o u l d b e s t b e v i e w e d a s a c h a n g e in t h e relation in w h i c h it s t a n d s to t h e u n i v e r s a l g r e e n n e s s , r a t h e r t h a n a c h a n g e in that u n i v e r s a l itself. W e m a y c o n c l u d e that t h e e x i s t e n c e of u n i v e r s a l s a s a b s t r a c t entities c a n a l s o b e s u p p o r t e d b y p o w e r f u l c o n s i d e r a t i o n s , j u s t as c a n t h e e x i s t e n c e of n u m b e r s as a b s t r a c t i n d i v i d u a l s . T h e n a priori c o n c e p t u a l t r u t h s s u c h as ' A n y t h i n g red is c o l o u r e d ' a n d ' N o s u r f a c e can b e red all o v e r a n d g r e e n all o v e r at o n c e ' , in b e i n g c o n c e r n e d with i n t e r n a l r e l a t i o n s b e t w e e n u n i v e r s a l s , will give u s a priori k n o w l e d g e of a realm of abstract e n t i t i e s . But this is n o t y e t to say that s u c h k n o w l e d g e will b e g e n u i n e l y s u b s t a n t i v e . F o r it is i m p o r t a n t to n o t e that w e h a v e not y e t e s t a b l i s h e d that u n i v e r s a l s (or i n d e e d n u m b e r s ) h a v e m i n d i n d e p e n d e n t e x i s t e n c e , let a l o n e that their e x i s t e n c e is n e c e s s a r y (that t h e y exist at all t i m e s in all p o s s i b l e w o r l d s ) . In o r d e r t o s e e that t h e r e is a g a p h e r e w a i t i n g to b e b r i d g e d , c o n s i d e r w h a t m i g h t naturally be said a b o u t t h e e x i s t e n c e of sentences a s abstract t y p e s . G i v e n that b o t h t h e v o c a b u l a r y a n d t h e r u l e s of s e n t e n c e f o r m a t i o n for a l a n g u a g e h a v e b e e n fixed, it is n a t u r a l to t h i n k of t h e s e n t e n c e s of that l a n g u a g e a s a l r e a d y e x i s t i n g , i n d e p e n d e n t l y of their b e i n g t o k e n e d in s p e e c h or w r i t i n g . A n d this is j u s t w h a t w e s a y : t h e r e are m a n y s e n t e n c e s of E n g l i s h that n o o n e h a s e v e r e x p r e s s e d , or p e r h a p s e v e r will. T h o s e s e n t e n c e s m a y r e m a i n u n e x p r e s s e d b e c a u s e t h e y are t o o c o m p l i c a t e d e v e r to b e u t t e r e d , or too silly; or s i m p l y b e c a u s e n o o n e e v e r h a p p e n s t o t h i n k of t h e m . N o r d o w e h a v e a n y u s e for t h e idea t h a t a s e n t e n c e - t y p e m i g h t u n d e r g o c h a n g e . T h e s e n t e n c e ' D a v i d is w i s e ' is as it is; it c a n n o t c h a n g e w i t h o u t b e c o m i n g another s e n t e n c e . Y e t w e a r e u n l i k e l y to b e t e m p t e d to t h i n k of s e n t e n c e s a s e x i s t i n g i n d e p e n d e n t l y of t h e r u l e s implicit in t h e p r a c t i c e s of t h o s e w h o s p e a k t h e l a n g u a g e . O n the c o n t r a r y , if t h o s e r u l e s h a d n e v e r a r i s e n in t h e w a y that t h e y h a v e (for e x a m p l e , in t h e c a s e of E n g l i s h , if t h e N o r m a n s h a d n e v e r i n v a d e d a n d c o n q u e r e d E n g l a n d ) , t h e n t h e s e n t e n c e s in question would never have existed. It is t h u s n a t u r a l to t h i n k of s e n t e n c e s a s a b s t r a c t b u t m i n d d e p e n d e n t e n t i t i e s , d e p e n d i n g for their e x i s t e n c e u p o n t h e r u l e s implicit i n t h e p r a c t i c e s of t h e n a t i v e s p e a k e r s of a l a n g u a g e . A


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similar p o s i t i o n is t h e n p o s s i b l e in c o n n e c t i o n w i t h n u m b e r s a n d u n i v e r s a l s . O n e m i g h t c o n c e d e t h a t t h e y are a b s t r a c t e n t i t i e s ( b e i n g n o n - p h y s i c a l a n d c h a n g e l e s s t h r o u g h o u t t h e t i m e of their e x i s t e n c e ) , b u t m a i n t a i n that their e x i s t e n c e s u p e r v e n e s u p o n t h e e x i s t e n c e , a n d p r o p e r t i e s , of t h e h u m a n m i n d . N o t e , h o w e v e r , that I d o n o t take m y s e l f to h a v e shown that s e n t e n c e s h a v e m i n d - d e p e n d e n t e x i s t e n c e . M y p o i n t h a s o n l y b e e n to e s t a b l i s h that s u c h a n idea m a k e s s e n s e , a n d h e n c e to s h o w that m o r e n e e d s to b e d o n e if w e a r e to e s t a b l i s h f u l l - b l o w n p l a t o n i s m w i t h r e s p e c t to n u m b e r s a n d u n i v e r s a l s . S o m e h a v e m a i n t a i n e d that s e n t e n c e s , t o o , h a v e n e c e s s a r y e x i s t e n c e , a n d I d o n o t claim to h a v e a n s w e r e d t h e m h e r e . 9

Objective Truth and Objective Necessity A r e t h e r e a n y r e a s o n s for b e l i e v i n g that n u m b e r s a n d u n i v e r s a l s a r e a b s t r a c t entities that h a v e a n e x i s t e n c e i n d e p e n d e n t of t h e h u m a n m i n d ? T h e m a i n a r g u m e n t for s u c h a c l a i m is p r e m i s e d u p o n o u r intuitive b e l i e f in t h e o b j e c t i v i t y of t r u t h s a b o u t s u c h e n t i t i e s . T h u s w e a r e i n c l i n e d to t h i n k that t h e t r u t h of ' T h e r e is s o m e t h i n g that n o t h i n g is ( n a m e l y a d r a g o n ) ' is w h o l l y i n d e p e n d e n t of o u r b e l i e f s a b o u t t h e m a t t e r . E v e n if w e w e r e all to b e l i e v e that t h e r e are d r a g o n s , it w o u l d still b e t r u e that t h e r e is s o m e t h i n g that n o t h i n g is ( n a m e l y a d r a g o n ) . I n d e e d , n o t o n l y a r e t r u t h s a b o u t u n i v e r s a l s i n d e p e n d e n t of o u r b e l i e f s , b u t w e a r e s t r o n g l y i n c l i n e d to t h i n k that t h e y a r e i n d e p e n d e n t of o u r v e r y e x i s t e n c e as w e l l . E v e n b e f o r e t h e r e w e r e a n y h u m a n b e i n g s , it w a s still t r u e that t h e r e w a s s o m e t h i n g that n o t h i n g w a s ( n a m e l y a d r a g o n ) . E q u a l l y , e v e n if t h e r e h a d n e v e r b e e n a n y h u m a n b e i n g s , it w o u l d still h a v e b e e n true that t h e r e is s o m e t h i n g that n o t h i n g is ( n a m e l y a d r a g o n ) . In w h i c h c a s e it w o u l d s e e m that u n i v e r s a l s t h e m s e l v e s ( t h e e n t i t i e s s u c h t r u t h s a r e a b o u t ) m u s t exist i n d e p e n d e n t l y of t h e h u m a n m i n d . S i m i l a r a r g u m e n t s c a n b e d e p l o y e d in s u p p o r t of t h e m i n d i n d e p e n d e n t existence of n u m b e r s . Indeed, in this case the i m p r e s s i o n of o b j e c t i v i t y i s , if a n y t h i n g , e v e n s t r o n g e r . T h e t r u t h of '7 is p r i m e ' is, w e t h i n k , q u i t e i n d e p e n d e n t o f a n y t h i n g 9

S e e , f o r e x a m p l e , J e r r o l d K a t z , Language

Blackwell, 1981).

and Other Abstract

Objects

(Oxford:


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w e m i g h t b e l i e v e a b o u t t h e m a t t e r . E v e n if w e all b e l i e v e d o t h e r w i s e — e i t h e r t h r o u g h m i s t a k e o r s o m e sort of collective m a d n e s s — i t w o u l d still b e true t h a t 7 is p r i m e . M o r e o v e r , w e are i n c l i n e d to t h i n k that t h e t r u t h s of m a t h e m a t i c s a r e i n d e p e n d e n t of o u r v e r y e x i s t e n c e . E v e n b e f o r e t h e r e w e r e a n y h u m a n b e i n g s , or e v e n if t h e r e h a d n e v e r b e e n a n y h u m a n b e i n g s , it w o u l d still h a v e b e e n t h e c a s e that 2 + 2 = 4 . For e x a m p l e , if t h e r e w e r e 2 a p p l e s a n d 2 p e a r s lying b e n e a t h a particular tree o n a d a y e x a c t l y 2 0 m i l l i o n y e a r s a g o , t h e n it m u s t still h a v e b e e n t h e c a s e that t h e r e w e r e 4 p i e c e s of fruit u n d e r the t r e e , e v e n t h o u g h t h e r e w e r e n o i n t e l l i g e n t a g e n t s in e x i s t e n c e to r e c o g n i z e t h e fact. It a p p e a r s that t h e t r u t h s of m a t h e m a t i c s are m i n d - i n d e p e n d e n t , o b t a i n i n g i n d e p e n d e n t l y of facts a b o u t , o r e v e n t h e v e r y e x i s t e n c e of, the h u m a n m i n d . Y e t s u c h t r u t h s i n v o l v e r e f e r e n c e to i n d i v i d u a l a b s t r a c t o b j e c t s ( t h e n u m b e r s ) , a s w e a r g u e d a b o v e . T h e n h o w c o u l d t h o s e o b j e c t s , in t u r n , fail to exist i n d e p e n d e n t l y of t h e h u m a n m i n d ? C o m p a r e : it w o u l d still h a v e b e e n t h e c a s e that E v e r e s t is the tallest m o u n t a i n in t h e w o r l d , e v e n if t h e r e h a d n e v e r b e e n a n y h u m a n b e i n g s in e x i s t e n c e to a p p r e c i a t e t h e fact. B u t this s u r e l y c o u l d n o t b e s o , u n l e s s E v e r e s t itself w o u l d still h a v e e x i s t e d in t h e a b s e n c e of h u m a n b e i n g s . M i n d - i n d e p e n d e n t truth s e e m s to require t h e m i n d i n d e p e n d e n t e x i s t e n c e of t h e o b j e c t s that figure in t h o s e t r u t h s . S o , t o o , in t h e c a s e of m a t h e m a t i c s : if t h e truth of '2 + 2 = 4 ' is i n d e p e n d e n t of t h e h u m a n m i n d , t h e n t h e o b j e c t s w i t h w h i c h it d e a l s ( n a m e l y , t h e n u m b e r s 2 a n d 4) m u s t h a v e a m o d e of e x i s t e n c e t h a t is i n d e p e n d e n t of t h e h u m a n m i n d . It a p p e a r s that t h e r e is a s t r o n g c a s e for s a y i n g that a b s t r a c t entities d o h a v e m i n d - i n d e p e n d e n t e x i s t e n c e . In this c a s e o u r a priori k n o w l e d g e of t h e p r o p e r t i e s of, a n d r e l a t i o n s b e t w e e n , s u c h e n t i t i e s (of t h e k i n d that p l a t o n i s t s m a i n t a i n is available to u s t h r o u g h m a t h e m a t i c a l p r o o f a n d c o n c e p t u a l a n a l y s i s ) will b e g e n u i n e l y s u b s t a n t i v e . B u t it d o e s n o t y e t f o l l o w t h a t a b s t r a c t e n t i t i e s h a v e n e c e s s a r y e x i s t e n c e , e x i s t i n g at all t i m e s in all p o s s i b l e w o r l d s . T h e r e a r e of c o u r s e m a n y t h i n g s t h a t exist i n d e p e n d e n t l y of o u r m i n d s ( E v e r e s t , for e x a m p l e ) that d o n o t h a v e n e c e s s a r y e x i s t e n c e . A r e t h e r e , t h e n , a n y a r g u m e n t s to s u p p o r t t h e s t r o n g e r c o n c l u s i o n o f n e c e s s a r y e x i s t e n c e for n u m b e r s and universals?

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T h e r e is i n d e e d s u c h a n a r g u m e n t , p r e m i s e d u p o n t h e c l a i m that t h e t r u t h s of m a t h e m a t i c s , a n d m a n y t r u t h s a b o u t u n i v e r sals, a r e necessary—being true w i t h r e s p e c t to all t i m e s in all possible worlds. T h u s n o matter h o w different the world might h a v e b e e n f r o m t h e w a y it actually is, it w o u l d still h a v e b e e n the c a s e that 2 + 2 = 4 , a n d it w o u l d still h a v e b e e n t h e c a s e that n o s u r f a c e c a n be r e d all o v e r a n d g r e e n all o v e r at o n c e . W e are s t r o n g l y inclined to b e l i e v e that t r u t h s s u c h as t h e s e h o l d c o m e w h a t m a y , n o m a t t e r w h a t else m a y or m a y n o t b e true of t h e world, and n o matter h o w different the world might possibly h a v e b e e n . T h e n h o w c o u l d t h e n u m b e r s 2 a n d 4 n o t exist in all p o s s i b l e w o r l d s , g i v e n that '2 + 2 = 4 ' is b o t h true with r e s p e c t to e v e r y p o s s i b l e w o r l d , a n d about t h e n u m b e r s 2 a n d 4? A n d s i n c e t h e truth ' N o s u r f a c e can be red all o v e r a n d g r e e n all o v e r at the s a m e t i m e ' is a b o u t t h e u n i v e r s a l s r e d n e s s a n d g r e e n n e s s ( a c c o r d i n g to the a r g u m e n t s p r e s e n t e d earlier), h o w c o u l d t h o s e e n t i t i e s , t o o , n o t exist in all p o s s i b l e w o r l d s ? It s e e m s that t r u t h s that a r e n e c e s s a r y m u s t require the n e c e s s a r y e x i s t e n c e of t h e entities those truths concern. T h e c o n c l u s i o n of this c h a p t e r is that t h e r e is a s e e m i n g l y p o w e r f u l c a s e s u p p o r t i n g p l a t o n i s m with r e s p e c t to n u m b e r s a n d u n i v e r s a l s . T h e r e a p p e a r to b e c o n v i n c i n g a r g u m e n t s for b e l i e v i n g that t h e r e a r e abstract e n t i t i e s that n o t o n l y exist i n d e p e n d e n t l y of t h e h u m a n m i n d , b u t that exist at all t i m e s in all p o s s i b l e w o r l d s . In the n e x t c h a p t e r w e shall c o n s i d e r w h a t an e m p i r i c i s t c a n d o to u n d e r m i n e t h e s e a r g u m e n t s . W e shall also c o n s i d e r w h e t h e r a n e m p i r i c i s t h a s a n y p o s i t i v e a r g u m e n t s for t h i n k i n g that p l a t o n i s m is false.

3 The Empiricist Case against Platonism H A V I N G s e t o u t t h e a r g u m e n t s s u p p o r t i n g p l a t o n i s m in c h a p t e r 2, in this c h a p t e r I shall p r e s e n t t h e m a i n a r g u m e n t s t h a t , f r o m an e m p i r i c i s t p e r s p e c t i v e , c a n b e d e p l o y e d a g a i n s t it.

Reducing Universals T h e m o s t u r g e n t task f a c i n g an e m p i r i c i s t is to u n d e r m i n e the c a s e for p l a t o n i s m . T h i s h a s g e n e r a l l y b e e n a t t e m p t e d via a s p e c i e s of r e d u c t i o n i s m . T h e i n t e n t i o n h a s b e e n to s h o w that w h a t a p p e a r s to b e talk a b o u t abstract e n t i t i e s is really talk a b o u t s o m e t h i n g e l s e , m o s t u s u a l l y i n t e r n a l relations b e t w e e n i d e a s in o u r m i n d s . If o n e c o u l d t h u s r e d u c e a b s t r a c t - o b j e c t talk to talk a b o u t n o n - c o n t i n g e n t f e a t u r e s of t h e h u m a n m i n d , it w o u l d h a v e b e e n s h o w n that t h e t r u t h s o f logic a n d m a t h e m a t i c s , w h i l e a p r i o r i , a r e n o t g e n u i n e l y s u b s t a n t i v e . For t h e y w o u l d n e i t h e r g i v e u s k n o w l e d g e that is c o n t i n g e n t (as is o u r knowledge of our o w n current mental states), nor knowledge that r e l a t e s to a n y a s p e c t of reality o u t s i d e o u r m i n d s . T o a d o p t t h i s r e d u c t i o n i s t strategy is t o try to s h o w that t h e s u b j e c t - m a t t e r of logic a n d m a t h e m a t i c s c a n b e i n t e r p r e t e d a d e q u a t e l y w i t h o u t r e f e r e n c e to abstract e n t i t i e s . In c o n n e c t i o n w i t h logic, a n d w i t h t h e sort of c o n c e p t u a l a n a l y s i s that o n e f i n d s in p h i l o s o p h y , t h e t a s k is relatively e a s y . W e c a n i n t e r p r e t t h e s e d i s c i p l i n e s as b e i n g c o n c e r n e d w i t h r e l a t i o n s b e t w e e n rules, c o n c e i v i n g of r u l e s as m i n d - d e p e n d e n t e n t i t i e s , r e d u c i b l e in t u r n to t h e s e m a n t i c i n t e n t i o n s of t h o s e w h o e m p l o y t h o s e r u l e s . T h u s ' A n y t h i n g r e d is c o l o u r e d ' m a y b e u n d e r s t o o d to b e t r u e in v i r t u e of a r e l a t i o n o b t a i n i n g b e t w e e n t h e c o n c e p t s red a n d colour, w h e r e t h e s e in t u r n a r e t a k e n to b e r u l e s for

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c l a s s i f y i n g i t e m s in t h e w o r l d . A n d t h e rule of classification e x p r e s s e d b y t h e w o r d ' r e d ' will itself c o n s i s t in t h e m a n n e r in w h i c h m o s t u s e r s of that w o r d i n t e n d to c o n t i n u e to e m p l o y it. T h i s is in fact t h e s t a n d a r d e m p i r i c i s t line: t r u t h s of logic a n d c o n c e p t u a l a n a l y s i s a r e analytic, b e i n g c o n c e r n e d o n l y w i t h r e l a t i o n s b e t w e e n c o n c e p t s , w h e r e t h e s e in t u r n a r e u n d e r s t o o d to r e d u c e to facts a b o u t t h e h u m a n m i n d . ( N o t e t h a t w h i l e I h a v e h e r e i d e n t i f i e d c o n c e p t s w i t h r u l e s of classification, m o s t traditional e m p i r i c i s t s h a v e t h o u g h t of t h e m a s images. B u t the w e a k n e s s e s in t h e i m a g i s t t h e o r y of c o n c e p t s h a v e b e e n l o n g r e c o g n i z e d . In fact n o i m a g e , or s e q u e n c e of i m a g e s , c a n carry u n a i d e d t h e c o n t e n t of e v e n a s i m p l e p r o p o s i t i o n such as ' G r a s s is g r e e n ' , let a l o n e of a c o m p l e x p r o p o s i t i o n like 'Life m a y b e d i s c o v e r e d on M a r s in t h e next ten or t w e l v e y e a r s ' . ) D o e s a n y s u c h f o r m of r e d u c t i o n i s m a b o u t c o n c e p t s h a v e t h e r e s o u r c e s to reply to t h e p l a t o n i s t a r g u m e n t s f r o m o b j e c t i v e truth a n d n e c e s s i t y ? T h e natural m o v e w o u l d b e to i n t e r p r e t s e n t e n c e s that s e e m to i n v o l v e g e n e r a l i z a t i o n s a b o u t a b s t r a c t u n i v e r s a l s as b e i n g , c o v e r t l y , s t a t e m e n t s a b o u t c o n c e p t s , or i d e a s in o u r m i n d s . W e s h o u l d t h e n r e g a r d t h e c o n t e n t of ' T h e r e is s o m e t h i n g that n o t h i n g is ( n a m e l y a d r a g o n ) ' a s b e i n g g i v e n in reality b y a s e n t e n c e s u c h a s ' T h e r e is s o m e idea that a p p l i e s to n o t h i n g ( n a m e l y t h e idea of a d r a g o n ) ' . W e c a n n o t , h o w e v e r , take the most obvious option with such statements w h e n they relate to s i t u a t i o n s in w h i c h t h e r e a r e n o h u m a n b e i n g s . W e c a n n o t , for e x a m p l e , i n t e r p r e t ' E v e n if t h e r e h a d n e v e r b e e n a n y h u m a n b e i n g s , it w o u l d still h a v e b e e n true t h a t t h e r e is s o m e t h i n g t h a t n o t h i n g is ( n a m e l y a d r a g o n ) ' to m e a n ' E v e n if t h e r e h a d n e v e r b e e n a n y h u m a n s , t h e r e w o u l d still h a v e b e e n s o m e idea that a p p l i e s to n o t h i n g ' . N o r c a n w e i n t e r p r e t '20 million y e a r s a g o t h e r e w a s s o m e t h i n g that g r a s s a n d l e a v e s h a d in c o m m o n ' to b e s a y i n g ' 2 0 million y e a r s a g o t h e r e w a s s o m e i d e a t h a t a p p l i e d to b o t h g r a s s a n d l e a v e s ' . F o r t h e s e s e n t e n c e s w o u l d t h e n i m p l y t h e e x i s t e n c e of i d e a s in s i t u a t i o n s in w h i c h t h e r e a r e n o i n t e l l i g e n t a g e n t s to p o s s e s s t h e m , w h i c h w o u l d b e absurd. In fact, h o w e v e r , t h e r e is n o s p e c i a l p r o b l e m h e r e . W e c a n r a t h e r t a k e t h e first s e n t e n c e to s a y that t h e r e is s o m e i d e a ( n a m e l y o u r — p r e s e n t l y e x i s t i n g — i d e a of a d r a g o n ) t h a t a p p l i e s

The Case against

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to n o t h i n g in a w o r l d t h a t differs f r o m o u r s o n l y in n e v e r h a v i n g contained any h u m a n beings. A n d w e can take the second s e n t e n c e to say that t h e r e is s o m e idea that a p p l i e s to g r a s s 2 0 million y e a r s a g o a n d to l e a v e s 2 0 million y e a r s a g o . All w e n e e d for this is t h e t h e s i s that p r e s e n t l y e x i s t i n g i d e a s c a n a p p l y to t h i n g s across t i m e (as w h e n w e e m p l o y t h e m in t h o u g h t s a b o u t t h e r e m o t e p a s t or f u t u r e ) , or across w o r l d s (as w h e n w e e m p l o y t h e m in t h o u g h t s a b o u t a w o r l d in w h i c h the h u m a n s p e c i e s n e v e r e v o l v e d ) , w i t h o u t h a v i n g to exist at t h o s e t i m e s o r in t h o s e worlds. A similar m o v e e n a b l e s u s to a v o i d the a r g u m e n t f r o m n e c e s s a r y truth to t h e n e c e s s a r y e x i s t e n c e of u n i v e r s a l s . F o r if this a r g u m e n t w e r e to b e valid, w e s h o u l d h a v e to i n t e r p r e t t h e n e c e s s i t y of ' N o s u r f a c e c a n b e r e d all o v e r a n d g r e e n all o v e r at o n c e ' a s h o l d i n g in v i r t u e of a truth of t h e f o l l o w i n g sort: F o r all w o r l d s , w , a n d all t i m e s , t, t h e c o n c e p t s red a n d green e x c l u d e o n e a n o t h e r in w at t. T h i s w o u l d i m p l y t h e e x i s t e n c e of c o n c e p t s (that is, u n i v e r s a l s ) at t h e t i m e s a n d in t h e w o r l d s w h e r e t h e original s e n t e n c e is t r u e (that is, at all t i m e s in all p o s s i b l e w o r l d s ) . But in fact t h e r e is n o t h i n g to s t o p u s r e g a r d i n g t h e n e c e s s i t y of that s e n t e n c e as h o l d i n g in v i r t u e of a t r u t h of t h e f o l l o w i n g f o r m : F o r all w a y s of t h i n k i n g of a w o r l d , w, a n d all w a y s of t h i n k i n g o f a t i m e , t, t h e c o n c e p t s red in world w at time t a n d green in world w at time t are ( n o w ) m u t u a l l y e x c l u s i v e . T h e i d e a h e r e is that n o m a t t e r h o w w e t h i n k of p o s s i b l e s i t u a t i o n s , o u r c o n c e p t s (ideas) of red a n d g r e e n e x c l u d e o n e a n o t h e r , p r o v i d e d t h a t t h e y o c c u r in t h o u g h t s a b o u t o n e a n d t h e s a m e s u c h s i t u a t i o n . A n e m p i r i c i s t c a n t h u s m a i n t a i n that a n a l y t i c t r u t h s , w h i l e b e i n g t r u e in v i r t u e of m e r e l y p r e s e n t l y e x i s t i n g i d e a s , n e v e r t h e l e s s c o n s t r a i n o u r talk a n d t h o u g h t a b o u t all o t h e r t i m e s a n d p o s s i b l e w o r l d s . W e c a n t h u s h o l d o n to t h e objectivity of at l e a s t s o m e n e c e s s a r y t r u t h s ( n a m e l y , t h o s e t h a t are a n a l y t i c ) , w h i l e b e i n g c o m m i t t e d o n l y to t h e e x i s t e n c e of c o n c e p t s as i d e a s in t h e h u m a n m i n d . N o t i c e , h o w e v e r , t h a t in t h u s e x p l a i n i n g a w a y t h e k i n d of talk w h i c h l e n d s c r e d e n c e t o t h e e x i s t e n c e o f abstract u n i v e r s a l s , w e a r e n o t t h e r e b y p r e v e n t e d f r o m r e c o g n i z i n g t h e e x i s t e n c e of

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immanent u n i v e r s a l s , as f o r m i n g p a r t of t h e n a t u r a l w o r l d . W e c a n a l l o w that t h e r e is a s e n s e o f ' G r a s s a n d l e a v e s h a v e s o m e t h i n g in c o m m o n ' that is n o t m e r e l y a b o u t i d e a s in o u r m i n d s , b u t r a t h e r c l a i m s that t h e r e is s o m e t h i n g that is partially p r e s e n t in individual l e a v e s a n d b l a d e s of g r a s s , w h i c h e x p l a i n s their c o m m o n a p p e a r a n c e . I c a n s e e n o r e a s o n w h y e m p i r i c i s t s s h o u l d o b j e c t to t h e e x i s t e n c e of i m m a n e n t u n i v e r s a l s . F o r w h i l e s u c h u n i v e r s a l s will b e g e n u i n e l y m i n d - i n d e p e n d e n t , f o r m i n g part of t h e n a t u r a l u n i v e r s e j u s t as m u c h as i n d i v i d u a l m o u n t a i n s a n d t r e e s d o , w e shall h a v e n o a priori k n o w l e d g e of t h e m . N o r will t h e y exist in all p o s s i b l e w o r l d s . O n the c o n t r a r y , it will be the b u s i n e s s o f t h e n a t u r a l s c i e n c e s to d i s c o v e r w h a t c o m m o n p r o p e r t i e s t h e r e really a r e in t h e actual w o r l d that explain the c a u s a l p o w e r s i n d i v i d u a l o b j e c t s h a v e in c o m m o n with o n e another.

Reducing N u m b e r s R e d u c t i o n i s m in m a t h e m a t i c s is a m o r e c o m p l e x affair. T h i s is partly b e c a u s e w e s e e m to h a v e t e r m s h e r e w h i c h p u r p o r t to refer to individual t h i n g s (that is, t h e individual n u m b e r s ) , a n d it is n o t s o o b v i o u s h o w t h e s e m a y b e r e d u c e d to r u l e s or psychological p h e n o m e n a . Nevertheless, m a n y of those w h o p u r s u e d t h e logicist p r o g r a m m e in m a t h e m a t i c s a r o u n d t h e t u r n of this c e n t u r y w e r e a t t e m p t i n g to s h o w h o w t h e t r u t h s of a r i t h m e t i c c o u l d b e r e d u c e d to t h o s e of logic (with t h e s e in their t u r n b e i n g s h o w n to b e a n a l y t i c ) . If t h i s p r o g r a m m e c o u l d b e carried t h r o u g h , a n d if it c o u l d b e s h o w n t h a t a n a l y t i c t r u t h s are not about anything outside the h u m a n mind, then the mindd e p e n d e n c e of n u m b e r s , t o o , w o u l d h a v e b e e n e s t a b l i s h e d . N o t e , h o w e v e r , that it is p o s s i b l e to b e a logicist a n d a p l a t o n i s t at t h e s a m e t i m e (as F r e g e in fact w a s ) . F o r o n e m i g h t c l a i m t h a t t h e t r u t h s of logic, a n d a n a l y t i c t r u t h s g e n e r a l l y , o b t a i n in virtue of facts a b o u t n e c e s s a r i l y e x i s t i n g u n i v e r s a l s . T o r e j e c t p l a t o n i s m a b o u t n u m b e r s o n e m i g h t also n e e d to r e j e c t p l a t o n i s m a b o u t u n i v e r s a l s ( t h o u g h n o t vice v e r s a ) . T h e first s t e p in t h e logicist p r o g r a m m e w a s to realize that s t a t e m e n t s of n u m b e r of the f o r m ' T h e r e are n F s ' a r e b e s t u n d e r s t o o d as s t a t e m e n t s a b o u t c o n c e p t s (or a s a b o u t t h e s e t s of

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t h i n g s t h o s e c o n c e p t s p i c k o u t ) . In t h e last c h a p t e r w e n o t e d , in connection with the sentence 'Jupiter has 4 m o o n s ' , that the n u m b e r 4 is certainly n o t a n a t t r i b u t e of e a c h i n d i v i d u a l m o o n . It m i g h t b e r e p l i e d that this d o e s n o t y e t s h o w that n u m b e r s a r e not ordinary attributes. For they m a y b e distinctive in being a t t r i b u t e s , n o t of i n d i v i d u a l t h i n g s , b u t of collections of s u c h t h i n g s . B u t in fact t h e r e a r e s e v e r e difficulties w i t h s u c h a v i e w . For o n e thing, the very s a m e physical collection can have d i f f e r e n t n u m b e r s a p p l i e d to it. T h u s 1 p a c k of c a r d s c a n also b e d e s c r i b e d a s 4 s u i t s , or as 5 2 c a r d s . M o r e o v e r , t h e r e a r e p r o b l e m s w i t h t h e n u m b e r 0. If t h e n u m b e r of M a r y ' s c h i l d r e n is 0, t h e n t h e r e exists n o collection for 0 to b e a n a t t r i b u t e of. T h e s e difficulties can easily b e resolved if s t a t e m e n t s of n u m b e r are s t a t e m e n t s a b o u t c o n c e p t s . T h e n 'Jupiter h a s 4 m o o n s ' states of the c o n c e p t moon of Jupiter that it is instantiated 4 times, and 'Mary has 0 children' says of the c o n c e p t child of Mary that it is n o t i n s t a n t i a t e d at a l l . In t h e s a m e w a y , w h a t c h a n g e s w h e n t h e p a c k of c a r d s m a y v a r i o u s l y b e d e s c r i b e d a s 'V, ' 4 ' , or ' 5 2 ' is t h e c o n c e p t i n v o l v e d in t h e s t a t e m e n t (pack, suit, a n d card r e s p e c t ively). B u t n o t e t h a t it d o e s n o t follow f r o m this that n u m b e r s t h e m s e l v e s a r e a t t r i b u t e s o f c o n c e p t s , or s e c o n d - l e v e l c o n c e p t s . F o r , a s w e n o t e d in t h e last c h a p t e r , s e n t e n c e s of t h e f o r m ' T h e r e are n F s ' c a n b e r e w r i t t e n a s i d e n t i t i e s , s a y i n g , in e f f e c t , ' T h e n u m b e r of t h i n g s falling u n d e r t h e c o n c e p t F is n o n e o t h e r t h a n n ' . W h i l e t h e w h o l e s t a t e m e n t c a n b e r e g a r d e d as b e i n g a b o u t t h e c o n c e p t F, t h e n u m e r a l ' n ' m a y still b e t r e a t e d a s a p r o p e r name. 1

T h e crucial c o n s i d e r a t i o n w a s t h e n to n o t i c e that n u m e r i c a l i d e n t i t y c a n b e d e f i n e d as a relation b e t w e e n c o n c e p t s . T h u s to say t h a t t h e n u m b e r of Fs is n o n e o t h e r t h a n t h e n u m b e r of G s c a n b e a n a l y s e d as s a y i n g that t h e i n s t a n c e s of t h e c o n c e p t F m a y b e p l a c e d in a o n e - t o - o n e relation to t h e i n s t a n c e s of t h e c o n c e p t G, w h e r e t h e i d e a of s u c h a r e l a t i o n c a n b e d e f i n e d w i t h o u t m e n t i o n i n g n u m b e r s . T o g e t t h e feel of this s u g g e s t i o n , n o t i c e that a w a i t e r c a n tell that t h e n u m b e r of b o w l s o n t h e table is t h e s a m e as t h e n u m b e r of p l a t e s w i t h o u t h a v i n g to c o u n t , b y s e e i n g that e v e r y b o w l s t a n d s o n a p l a t e , t h a t e v e r y p l a t e h a s a Alternatively, 'Jupiter h a s 4 m o o n s ' c a n be r e g a r d e d as saying of t h e set of m o o n s o f J u p i t e r t h a t it h a s 4 m e m b e r s , a n d ' M a r y h a s 0 c h i l d r e n ' c a n b e u n d e r s t o o d t o s a y o f t h e s e t o f M a r y ' s c h i l d r e n t h a t it is e m p t y . 1

38

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b o w l s t a n d i n g o n it, t h a t all p l a t e s o n w h i c h a n y g i v e n b o w l s t a n d s a r e t h e v e r y s a m e (that is, that t h e b o w l s t a n d s o n j u s t o n e p l a t e ) , a n d that all b o w l s s t a n d i n g o n a n y g i v e n p l a t e are the v e r y s a m e (that is, that j u s t o n e b o w l s t a n d s o n t h a t p l a t e ) . T h e individual n u m b e r s c a n t h e n b e i n t r o d u c e d r e c u r s i v e l y , d e f i n i n g 0 a s t h e n u m b e r of t h i n g s that a r e n o t i d e n t i c a l w i t h t h e m s e l v e s , 1 a s t h e n u m b e r of t h i n g s that a r e i d e n t i c a l w i t h 0, 2 a s t h e n u m b e r of t h i n g s that are identical w i t h e i t h e r 0 or 1, a n d s o o n . In w h i c h c a s e ' M a r y h a s 0 c h i l d r e n ' m a y b e a n a l y s e d as s a y i n g that t h e c o n c e p t child of Mary is o n e - t o - o n e c o r r e l a t e d with t h e c o n c e p t not identical with itself. A n d to s a y that t h e E a r t h has 1 m o o n m a y b e u n d e r s t o o d as s a y i n g that t h e c o n c e p t moon of the Earth is o n e - t o - o n e c o r r e l a t e d w i t h t h e c o n c e p t identical with 0. A n d s o o n . S u c h a n a n a l y s i s n e e d c o m m i t u s to n o t h i n g b e s i d e s c o n c e p t s ( r e d u c i b l e in turn to facts a b o u t t h e h u m a n m i n d , for an e m p i r i c i s t ) a n d the r e l a t i o n s b e t w e e n t h e m . 2

T h e p r o j e c t of logicist r e d u c t i o n in m a t h e m a t i c s w e n t o u t of f a s h i o n in the early d e c a d e s of this c e n t u r y , for a variety of technical r e a s o n s , t h o u g h it h a s b e e n revitalized a g a i n r e c e n t l y by C r i s p i n W r i g h t ( c o n t r a r y to his i n t e n t i o n ) . O t h e r f o r m s of r e d u c t i o n h a v e a l s o b e e n a t t e m p t e d . N o t a b l e a m o n g s t t h e s e is the m o d a l - s t r u c t u r a l a p p r o a c h of G e o f f r e y H e l l m a n , d e v e l o p ing s o m e i d e a s first s u g g e s t e d by P a u l B e n a c e r r a f . O n this a c c o u n t , m a t h e m a t i c s d e a l s w i t h t h e c l a s s of p o s s i b l e s t r u c t u r e s that s h a r e t h e p r o p e r t i e s of t h e n a t u r a l n u m b e r s e q u e n c e (infinite e x t e n t , e a c h m e m b e r h a v i n g a u n i q u e s u c c e s s o r , a n d so o n ) . T h e s t r u c t u r e s in q u e s t i o n are ( w h e n i n s t a n t i a t e d ) c o n c r e t e o n e s — f o r e x a m p l e , t h e s e q u e n c e of i n s c r i p t i o n s V , '**', '***', '****', a n d s o o n . S o t h e r e is n o c o m m i t m e n t to a b s t r a c t o b j e c t s . Y e t b e c a u s e t h e a c c o u n t is m o d a l , d e a l i n g w i t h all possible s t r u c t u r e s s h a r i n g c e r t a i n p r o p e r t i e s , it c a n a c h i e v e t h e u n i v e r sality (particularly t h e applicability to o t h e r p o s s i b l e w o r l d s ) of mathematics. 3

4

5

F r e g e ' s a c t u a l d e f i n i t i o n s w e r e g i v e n in t e r m s o f s e t s o f s e t s — a s it t u r n s o u t , d i s a s t r o u s l y , in t h e light o f R u s s e l l ' s P a r a d o x . S e e C r i s p i n W r i g h t , Frege's Conception of Numbers as Objects ( A b e r d e e n : A b e r d e e n U n i v e r s i t y P r e s s , 1 9 8 3 ) , c h s . 3 a n d 4 , for f u r t h e r d i s c u s s i o n . 2

S e e h i s Frege's Conception, c h . 4 . S e e h i s Mathematics without Numbers (Oxford: Oxford University 1989). S e e ' W h a t N u m b e r s C o u l d N o t B e ' , Philosophical Review, 1 9 6 5 . 3 4

5

Press,

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39

Platonism

It r e m a i n s t r u e , h o w e v e r , t h a t it w o u l d b e a f e a r s o m e a c h i e v e m e n t to carry t h r o u g h to c o m p l e t i o n a n y v e r s i o n of t h e r e d u c t i o n i s t p r o j e c t . It m i g h t t h e r e f o r e b e w i s e for e m p i r i c i s t s to a d o p t s o m e a l t e r n a t i v e s t r a t e g y f o r o p p o s i n g p l a t o n i s m in m a t h e m a t i c s if t h e y c a n , w h i c h will carry less risk of failure on t e c h n i c a l g r o u n d s . F o r if t h e r e is a l e s s o n to be l e a r n e d h e r e f r o m t h e h i s t o r y o f p h i l o s o p h y , it is t h a t c o n c e p t u a l r e d u c t i o n s a r e r e m a r k a b l y difficult to c o m p l e t e s u c c e s s f u l l y . T h i s is especially likely to b e t h e c a s e w h e r e o u r d i s c o u r s e is v e r y h i g h l y d e v e l o p e d a n d c o m p l e x , a s is t h a t of m a t h e m a t i c s . ( C o m p a r e t h e failure o f t h e p h e n o m e n a l i s t r e d u c t i v e p r o g r a m m e , w h i c h a t t e m p t s to r e d u c e talk o f p h y s i c a l o b j e c t s to talk a b o u t p a t t e r n s in e x p e r i e n c e . )

M i n d - D e p e n d e n t Existence T h e r e i s , h o w e v e r , a n o t h e r s t r a t e g y available to an e m p i r i c i s t , w h i c h c a r r i e s l e s s risk of failure. W e can g r a n t that m a t h e m a t i c s is c o n c e r n e d w i t h a b s t r a c t o b j e c t s , m a k i n g n o a t t e m p t t o a n a l y s e a w a y s u c h a p p a r e n t r e f e r e n c e s to n u m b e r s as o c c u r s in '7 is p r i m e ' . B u t w e c a n d e n y that t h e s e o b j e c t s h a v e a n e x i s t e n c e t h a t is i n d e p e n d e n t o f t h e h u m a n m i n d . W e c a n r a t h e r claim that t h e i r e x i s t e n c e s u p e r v e n e s u p o n a s p e c t s of h u m a n activity — p a r t i c u l a r l y on t h e rules implicit in t h e practices of t h o s e w h o c o u n t , a d d , a n d s u b t r a c t — i n s u c h a w a y that t h e y w o u l d n o t h a v e e x i s t e d if h u m a n b e i n g s (or o t h e r intelligent a g e n t s ) h a d n e v e r e x i s t e d . S o w e m a y a l l o w that t h e r e a r e a b s t r a c t o b j e c t s , b u t d e n y t h a t t h e s e o b j e c t s exist n e c e s s a r i l y , or i n d e e d i n d e p e n d e n t l y o f t h e h u m a n m i n d . If fact w e c a n a d o p t f o r n u m b e r s j u s t t h e s o r t of p o s i t i o n that w e s k e t c h e d c o n c e r n i n g t h e m o d e of e x i s t e n c e of s e n t e n c e s in t h e last c h a p t e r . 6

B u t if n u m b e r s h a v e o n l y m i n d - d e p e n d e n t e x i s t e n c e , h o w a r e w e to e x p l a i n t h e fact t h a t w e a p p l y a r i t h m e t i c to r e m o t e r e g i o n s of t i m e , for e x a m p l e in c a l c u l a t i n g t h e orbit of t h e E a r t h m a n y m i l l i o n s of y e a r s in t h e p a s t or f u t u r e ( w h e n , w e m a y p r e s u m e , t h e r e a r e n o m i n d s for n u m b e r s to s u p e r v e n e upon)? I n d e e d , w h a t o f t h e p o i n t t h a t e v e n if t h e r e h a d n e v e r b e e n a n y h u m a n 6

A

view

o f t h i s s o r t is d e f e n d e d b y K a r l P o p p e r in Objective

( O x f o r d : Oxford University Press, 1972).

Knowledge

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b e i n g s , it w o u l d still h a v e b e e n t r u e t h a t 2 a p p l e s a n d 2 p e a r s w o u l d c o n s t i t u t e 4 p i e c e s of fruit? H o w c a n this b e s o , if i n s u c h a c a s e t h e r e w o u l d h a v e b e e n n o s u c h t h i n g s a s 2 a n d 4 ? It is w o r t h e x p l o r i n g in s o m e detail t h e w a y in w h i c h a n e m p i r i c i s t m i g h t r e s p o n d to t h e s e p r o b l e m s . T h e g e n e r a l s t r a t e g y will b e a s it w a s in t h e d i s c u s s i o n of u n i v e r s a l s a b o v e , n a m e l y to try to a c c o u n t for t h e t r u t h s i n q u e s t i o n i n t e r m s of t h e present existence of numbers alone. H o w is o n e w h o b e l i e v e s that n u m b e r s d o g e n u i n e l y exist a s a b s t r a c t o b j e c t s , b u t m i n d - d e p e n d e n t l y , to a c c o u n t for a t r u t h such as the following? E v e n if t h e r e h a d b e e n n o i n t e l l i g e n t a g e n t s , t h e n u m b e r of m o o n s of J u p i t e r w o u l d still h a v e b e e n 4 . S u p p o s e w e let 'a' d e s i g n a t e t h e actual w o r l d . T h e n w e m i g h t try e x p r e s s i n g the a b o v e truth as f o l l o w s : F o r all p o s s i b l e w o r l d s w , if w differs f r o m a o n l y in c o n t a i n i n g n o intelligent a g e n t s , t h e n t h e n u m b e r of m o o n s of J u p i t e r (in w ) is n o n e o t h e r t h a n 4 (in a ) . 7

T h e t h o u g h t h e r e is that w e c a n a v o i d c o m m i t m e n t t o t h e e x i s t e n c e of t h e n u m b e r 4 in a n y o t h e r w o r l d b e s i d e s t h e a c t u a l . T h e t r o u b l e , h o w e v e r , is t h a t t h e n u m b e r 4 , in a, s u r e l y c a n n o t b e i d e n t i c a l to (be n o n e o t h e r t h a n ) t h e n u m b e r of m o o n s of J u p i t e r in w w i t h o u t itself existing in w . W h a t w e really r e q u i r e is something having the following form: F o r all p o s s i b l e w o r l d s w , if w differs f r o m a o n l y in c o n t a i n i n g n o i n t e l l i g e n t a g e n t s , t h e n t h e n u m b e r (in a) of m o o n s of J u p i t e r (in w ) is n o n e o t h e r t h a n 4 (in a). H e r e all r e f e r e n c e s to n u m b e r s are c o n f i n e d to t h e actual w o r l d . T h e p r o b l e m is to find a f o r m of a c c o u n t that w o u l d h a v e s u c h a f e a t u r e . F o r it is b y n o m e a n s e a s y to s e e h o w a s i n g l e d e f i n i t e d e s c r i p t i o n (in this c a s e ' t h e n u m b e r of m o o n s of J u p i t e r ' ) c a n c o n t a i n r e f e r e n c e s to t w o distinct p o s s i b l e w o r l d s at o n c e . I t a k e it that all p l a t o n i s t s s h o u l d a g r e e that s t a t e m e n t s of t h e f o r m ' T h e r e a r e n F s ' a r e really s t a t e m e n t s of n u m e r i c a l i d e n t i t y , h a v i n g t h e f o r m ' T h e n u m b e r of Fs is n o n e o t h e r t h a n n ' . T h e y I s h o u l d s t r e s s t h a t talk o f ' p o s s i b l e w o r l d s ' , f o r a n e m p i r i c i s t , is m e r e l y a c o n v e n i e n t m o d e of s p e e c h , carrying n o c o m m i t m e n t to the real existence of worlds other than our own. 7

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s h o u l d also a c c e p t t h a t t h e criterion of n u m e r i c a l i d e n t i t y is o n e t o - o n e c o r r e l a t i o n b e t w e e n c o n c e p t s , in t h e m a n n e r e x p l a i n e d earlier. T h e n o u r target s t a t e m e n t m a y b e e x p r e s s e d b y something having the following general form: F o r all p o s s i b l e w o r l d s containing no intelligent c o n c e p t moon of Jupiter (in of t h i n g s s u c h t h a t . . . (in

w , if w differs f r o m a o n l y in a g e n t s , t h e n t h e i n s t a n c e s of t h e w) one-to-one correlate the n u m b e r a).

H e r e t h e d o t s w o u l d b e filled in b y t h e a p p r o p r i a t e d e f i n i t i o n of t h e n u m b e r 4 . In s u c h a c a s e w e w o u l d b e relying u p o n r e l a t i o n s of o n e - t o - o n e c o r r e s p o n d e n c e across possible worlds (that is, b e t w e e n w a n d a) to a v o i d c o m m i t m e n t to t h e e x i s t e n c e of n u m b e r s in a n y b u t t h e actual w o r l d . 8

B u t w h a t of t h e s e r e l a t i o n s of o n e - t o - o n e c o r r e s p o n d e n c e ? H o w c a n t h e y b o t h obtain a c r o s s p o s s i b l e w o r l d s a n d b e m i n d d e p e n d e n t ? T h e a n s w e r is that t h e y , in their t u r n , are n o t actual r e l a t i o n s b u t p o s s i b l e o n e s . For c o n s i d e r w h a t it m u s t m e a n to s a y that t h e r e a r e n F s , if a n e m p i r i c i s t i n s i s t s that c o n c e p t s ( a n d relations) are best u n d e r s t o o d as rules of classification. Certainly n o t that t h e r e is a n y actual rule of c o r r e s p o n d e n c e r e l a t i n g t h e n u m b e r n to t h e i n s t a n c e s of t h e c o n c e p t F . F o r in m a n y c a s e s n o s u c h rule will h a v e b e e n set u p . R a t h e r , it m u s t m e a n t h a t it is possible to c r e a t e s u c h a r u l e , for e x a m p l e b y c o u n t i n g . In full, t h e n , o u r a c c o u n t of o u r target s t a t e m e n t w o u l d r u n as f o l l o w s : F o r all p o s s i b l e w o r l d s w , if w differs f r o m a o n l y i n c o n t a i n i n g n o i n t e l l i g e n t a g e n t s , t h e n t h e r e is a n o t h e r p o s s i b l e w o r l d v w h i c h differs f r o m w o n l y in w h a t e v e r is r e q u i r e d for t h e r e to b e b o t h n u m b e r s a n d a rule of c o r r e l a t i o n s u c h that t h e i n s t a n c e s o f t h e c o n c e p t moon of Jupiter (in v) o n e - t o - o n e correlate t h e n u m b e r of t h i n g s s u c h t h a t . . . (in v ) . 9

E v e n if p l a t o n i s t s d o n o t a c c e p t t h e n e e d for d e f i n i t i o n s o f t h e i n d i v i d u a l n u m b e r s , t h e y m u s t c e r t a i n l y a g r e e t h a t d e s c r i p t i o n s of t h e f o r m ' T h e n u m b e r o f F s ' will c o m e t o d e s i g n a t e a p a r t i c u l a r n u m b e r in v i r t u e o f s o m e r e l a t i o n o b t a i n i n g b e t w e e n t h e n u m b e r in q u e s t i o n a n d t h e i n s t a n c e s of t h e c o n c e p t F. 8

O f c o u r s e t h e r e will n e e d t o b e r e s t r i c t i o n s in a p p l y i n g this s c h e m e , s o t h a t if t h e i n t e l l i g e n t a g e n t s in v a r e t o b e c o u n t i n g i n t e l l i g e n t a g e n t s , t h e n t h e y m u s t c o u n t all with the exception of themselves. O t h e r w i s e t h e s e n t e n c e ' E v e n if t h e r e h a d b e e n n o i n t e l l i g e n t a g e n t s , t h e n u m b e r o f i n t e l l i g e n t a g e n t s w o u l d still h a v e b e e n 0 ' will c o m e o u t a s f a l s e r a t h e r t h a n t r u e . 9

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W h i l e this d o e s n o t q u i t e restrict all r e f e r e n c e s to n u m b e r s to t h e actual w o r l d , it d o e s in effect restrict t h e m to w o r l d s in w h i c h t h e r e are intelligent a g e n t s , w h i c h is all that w e n e e d for n u m b e r s to h a v e m i n d - d e p e n d e n t e x i s t e n c e . W e c a n deal in similar m a n n e r with t h e n e c e s s a r y s t a t u s (truth a b o u t all p o s s i b l e w o r l d s ) of m a t h e m a t i c a l s t a t e m e n t s s u c h as '2 + 2 = 4 ' . W h a t initially c a u s e s u s a p r o b l e m h e r e is that s u c h t r u t h s s e e m naturally to b e r e p r e s e n t e d in t h e f o l l o w i n g f o r m : F o r all p o s s i b l e w o r l d s w , it is a t r u t h a b o u t w that 2 + 2 = 4 . F o r it is h a r d to s e e h o w a s t a t e m e n t a b o u t n u m b e r s c a n e x p r e s s a truth about a w o r l d , w i t h o u t n u m b e r s t h e m s e l v e s e x i s t i n g in that w o r l d . B u t in fact w e can e x p r e s s t h e c o n t e n t of o u r n e w target s t a t e m e n t s o m e w h a t as f o l l o w s : It is a t r u t h a b o u t a that 2 + 2 = 4 , a n d for all p o s s i b l e w o r l d s w , t h e truth (in a) of 2 + 2 = 4 is applicable to w . H e r e t h e idea of the applicability of a n u m e r i c a l truth is to b e c a s h e d o u t in a similar m a n n e r to t h a t o u t l i n e d a b o v e , i n v o l v i n g r e l a t i o n s a c r o s s w o r l d s b e t w e e n n u m b e r s a n d t h e i n s t a n c e s of c o n c e p t s . T h u s t h e applicability of 2 + 2 = 4 to a w o r l d in w h i c h t h e r e a r e n o intelligent a g e n t s w o u l d c o n s i s t in t h e f o l l o w i n g sorts of facts. If t h e i n s t a n c e s of t h e c o n c e p t apple under the tree in that w o r l d are o n e - t o - o n e c o r r e l a t e d t o t h e n u m b e r 2 in a, a n d if t h e i n s t a n c e s of t h e c o n c e p t pear under the tree in that w o r l d a r e similarly c o r r e l a t e d to t h e n u m b e r 2 in a, t h e n t h e i n s t a n c e s of t h e c o n c e p t apple or pear under the tree in that w o r l d a r e o n e - t o o n e c o r r e l a t e d to t h e n u m b e r 4 in a. H e r e w e h a v e p r e s e r v e d t h e intuitive t h o u g h t that n u m e r i c a l e q u a l i t i e s are n e c e s s a r y (that is, a p p l i c a b l e to all w o r l d s ) w i t h o u t c o m m i t m e n t to t h e e x i s t e n c e of n u m b e r s in a n y w o r l d s b u t t h o s e in w h i c h t h e r e are i n t e l l i g e n t agents.

Can there be Causal Contact? It a p p e a r s that a n e m p i r i c i s t c a n a d e q u a t e l y u n d e r m i n e t h e a r g u m e n t s that s e e m to s u p p o r t p l a t o n i s m . B u t d o e s a n e m p i r i c i s t h a v e a n y d i r e c t o b j e c t i o n to p l a t o n i s m ? W e h a v e s e e n that t h e r e is i n s u f f i c i e n t r e a s o n for b e l i e v i n g p l a t o n i s m t o b e

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t r u e , b u t a r e t h e r e a n y g o o d r e a s o n s for p o s i t i v e l y b e l i e v i n g it to b e false? T h e m a i n a r g u m e n t to this e f f e c t a r i s e s o u t of t h e q u e s t i o n w h e t h e r a p l a t o n i s t c a n g i v e a n a d e q u a t e a c c o u n t of our s u p p o s e d k n o w l e d g e of necessarily existing abstract entities. A s w e n o t e d in t h e last c h a p t e r , m a n y p l a t o n i s t s h a v e b e l i e v e d that w e p o s s e s s a special faculty of intellectual intuition, modelled by analogy with sense-perception. H o w e v e r , it is d o u b t f u l w h e t h e r this q u a s i - p e r c e p t u a l m o d e l is really c o h e r e n t . For h o w are w e to m a k e s e n s e of the idea that a c h a n g e l e s s , n e c e s s a r i l y e x i s t i n g e n t i t y ( w h i c h is w h a t p l a t o n i s t s s u p p o s e the n u m b e r 7 to b e ) c a n h a v e causal p o w e r s ? T h e p r o b l e m h e r e is that t h e c o n c e p t of causality is at least closely b o u n d u p w i t h c o u n t e r f a c t u a l a n d s u b j u n c t i v e c o n d i t i o n a l s . (A c o u n t e r f a c t u a l c o n d i t i o n a l h a s t h e form i f X had b e e n the c a s e , t h e n Y would have b e e n t h e c a s e ' . A s u b j u n c t i v e c o n d i t i o n a l h a s t h e f o r m i f X were to b e t h e c a s e , t h e n Y would be the c a s e ' . ) T o say that A c a u s e d B is to i m p l y that if A h a d not b e e n the c a s e , t h e n B w o u l d n o t h a v e ; a n d also to i m p l y that if in o t h e r c i r c u m s t a n c e s s o m e t h i n g sufficiently similar to A w e r e to be the c a s e , t h e n s o m e t h i n g similar to B w o u l d be a l s o . T h u s , if it is true that a s p a r k c a u s e d a particular e x p l o s i o n , t h e n it m u s t b e true that if t h e s p a r k h a d n o t o c c u r r e d , n o r w o u l d t h e e x p l o s i o n ( o t h e r t h i n g s b e i n g e q u a l ) . It m u s t a l s o b e true that in all o t h e r sufficiently similar c i r c u m s t a n c e s a s p a r k w o u l d b e f o l l o w e d by a n e x p l o s i o n . But w h e r e A is s o m e t h i n g that is n e c e s s a r i l y t h e c a s e , t h e s u p p o s i t i o n i f A h a d n o t b e e n s o ' will m a k e n o s e n s e . If t h e fact that 7 is p r i m e o b t a i n s at all t i m e s in all p o s s i b l e w o r l d s , as p l a t o n i s t s b e l i e v e , t h e n it will b e i m p o s s i b l e to s u p p o s e that 7 h a d n o t b e e n p r i m e . In w h i c h c a s e it c a n n o t b e t h e fact that 7 is p r i m e that c a u s e s o u r belief that it is; i n d e e d s u c h a fact c a n n o t b e a c a u s e at a l l . 10

A l t h o u g h t h e q u a s i - p e r c e p t u a l m o d e l is i n c o h e r e n t , it is n o t t h e o n l y p o s s i b l e w a y in w h i c h p l a t o n i s t s m i g h t c o n c e i v e of c a u s a l a c c e s s to t h e a b s t r a c t r e a l m . A n a l t e r n a t i v e m o d e l w o u l d b e a g r a v i t a t i o n a l o n e . J u s t a s it is t h e fact t h a t a n a s t e r o i d e n t e r s t h e g r a v i t a t i o n a l field of t h e E a r t h r a t h e r t h a n of M a r s ( w h i c h m a y for t h e s e p u r p o s e s b e t h o u g h t of as c h a n g e l e s s ) that P l a i n l y , t o s u p p o s e t h a t t h e e x i s t e n c e of n u m b e r s is t i m e l e s s r a t h e r t h a n n e c e s s a r y w o u l d n o t h e l p a t all h e r e . F o r h o w c o u l d a n a t e m p o r a l e n t i t y b e t h e c a u s e o f a t e m p o r a l e v e n t , s u c h a s t h e o n s e t of a belief? 1 0

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e x p l a i n s its s u b s e q u e n t orbit, s o it m a y b e t h e fact that o n e i n t u i t s t h e n a t u r e of 7 r a t h e r t h a n of s o m e o t h e r n u m b e r that e x p l a i n s o u r s u b s e q u e n t belief that 7 is p r i m e . W e m a y t h u s t h i n k of a b s t r a c t o b j e c t s as h a v i n g a s s o c i a t e d w i t h t h e m p e r m a n e n t (indeed necessarily existing) 'intuition-fields', such that w h e n t h e m i n d s t a n d s in t h e i n t u i t i o n - r e l a t i o n to o n e a b s t r a c t o b j e c t r a t h e r t h a n a n o t h e r , it is c a u s e d to h a v e o n e belief r a t h e r t h a n a n o t h e r . T h i s g i v e s u s a p p r o p r i a t e c o u n t e r factual a n d s u b j u n c t i v e c o n d i t i o n a l s . W e m a y truly say that if s o m e o n e h a d n o t i n t u i t e d the n a t u r e of 7 at that m o m e n t , t h e n t h e y w o u l d n o t h a v e c o m e to b e l i e v e that 7 is p r i m e ; a n d if in o t h e r similar c i r c u m s t a n c e s t h e y w e r e to intuit t h e n a t u r e of 7, t h e y w o u l d t h e n b e l i e v e that 7 is p r i m e . T h i s a c c o u n t e n a b l e s u s to m a k e s o m e h e a d w a y in e x p l a i n i n g h o w p l a t o n i c e n t i t i e s can b e c a u s e s . But it, t o o , faces s e v e r e p r o b l e m s . F o r e v e n if abstract o b j e c t s a r e a s s o c i a t e d w i t h p e r m a n e n t i n t u i t i o n - f i e l d s , it still h a s to b e p o s s i b l e to e x p l a i n w h y a n y g i v e n o b j e c t is a s s o c i a t e d w i t h o n e s u c h field r a t h e r t h a n a n o t h e r . Y e t s u c h e x p l a n a t i o n s will r e t u r n u s to t h e sort o f u n i n t e l l i g i b l e c o u n t e r f a c t u a l s m e t w i t h earlier. C o n s i d e r t h e g r a v i t a t i o n a l c a s e a g a i n . E v e n if it is t h e b a r e fact that an a s t e r o i d e n t e r s t h e gravitational field of t h e E a r t h r a t h e r t h a n of M a r s that e x p l a i n s its s u b s e q u e n t p a t t e r n of m o v e m e n t , it m u s t surely b e p o s s i b l e to e x p l a i n why t h e Earth h a s t h e g r a v i t a t i o n a l field that it h a s . A n d i n d e e d w e c a n p r o v i d e j u s t s u c h a n e x p l a n a t i o n , in t e r m s of t h e E a r t h ' s m a s s . T h e g e n e r a l m o r a l is that relational c a u s a l p o w e r s n e e d to b e e x p l i c a b l e in t e r m s of t h e c a t e g o r i c a l p r o p e r t i e s of t h e t h i n g s that p o s s e s s t h o s e p o w e r s . T h a t is to s a y , if s o m e t h i n g h a s t h e p o w e r to affect in a g i v e n w a y t h i n g s that c o m e to s t a n d in a c e r t a i n relation to it, t h e n this m u s t u l t i m a t e l y b e explicable in t e r m s of t h e n o n - r e l a t i o n a l p r o p e r t i e s that o b j e c t p o s s e s s e s . S o if t h e n u m b e r 7 h a s t h e p o w e r to c a u s e t h o s e w h o intuit it to b e l i e v e t h a t 7 is p r i m e , t h i s m u s t b e causally e x p l i c a b l e i n t e r m s of t h e p r o p e r t i e s of t h e n u m b e r 7. B u t this will c o m m i t u s o n c e a g a i n to s t a t e m e n t s s u c h as 'If 7 h a d n o t b e e n p r i m e it w o u l d n o t h a v e h a d t h e p o w e r s that it h a s ' — w h i c h a r e , as w e s a w a b o v e , unintelligible (given that 7 has necessary existence, a n d poss e s s e s its a t t r i b u t e s n e c e s s a r i l y ) . A further problem with the idea that platonic objects can have e f f e c t s o n t h e h u m a n m i n d (in e i t h e r o f t h e a b o v e v e r s i o n s ) , is

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that it r e q u i r e s u s to r e c o g n i z e a w h o l e n e w s p e c i e s of c a u s a l i t y , h i t h e r t o u n k n o w n to s c i e n c e . F o r w e w o u l d h a v e to b e l i e v e that an abstract object (non-physical and changeless) can have effects w i t h i n t h e n a t u r a l (physical a n d c h a n g i n g ) w o r l d . T h e difficulty faced h e r e by p l a t o n i s t s is similar to that f a c e d b y d u a l i s t s in t h e p h i l o s o p h y of m i n d . T h o s e w h o b e l i e v e that t h e m i n d is a n o n p h y s i c a l e n t i t y , or w h o b e l i e v e that m e n t a l e v e n t s s u c h a s t h o u g h t s , d e c i s i o n s , a n d i n t e n t i o n s are n o n - p h y s i c a l o n e s , a r e t h e n faced with t h e p r o b l e m of e x p l a i n i n g h o w t h e r e can b e causal c o n t a c t b e t w e e n n o n - p h y s i c a l e v e n t s a n d p h y s i c a l o n e s . For w e d o n o r m a l l y s u p p o s e that o u r t h o u g h t s a n d d e c i s i o n s cause o u r b o d i e s to m o v e in c e r t a i n w a y s . N o w I d o u b t w h e t h e r t h e r e is a n y o b j e c t i o n in p r i n c i p l e to the idea of s u c h c a u s a t i o n . But it d o e s conflict with a w e l l - e s t a b l i s h e d w o r k i n g h y p o t h e s i s of s c i e n c e , n a m e l y that all c a u s e s are physical o n e s . S c i e n c e h a s p r o g r e s s e d by i g n o r i n g the possibility of c a u s a tion b y spirits o r o t h e r n o n - p h y s i c a l e n t i t i e s , a n d by l o o k i n g w h e r e v e r p o s s i b l e for physical m e c h a n i s m s . S o the i m m e n s e e x p l a n a t o r y s u c c e s s of s c i e n c e g i v e s u s r e a s o n to b e d o u b t f u l , at least, a b o u t b o t h the q u a s i - p e r c e p t u a l a n d the gravitational m o d e l s e m p l o y e d by p l a t o n i s t s to explain o u r k n o w l e d g e of logic a n d m a t h e m a t i c s . If w e are i m p r e s s e d by t h e s u c c e s s of s c i e n c e , w e shall w i s h to insist that s u c h k n o w l e d g e s h o u l d b e e x p l a i n e d naturalistically, in t e r m s of t h e o p e r a t i o n of l a w s a n d p r o c e s s e s that s c i e n c e g i v e s u s s o m e r e a s o n to b e l i e v e in. W e shall r e t u r n to c o n s i d e r this idea in s o m e detail in c h a p t e r 9.

Platonism and Scepticism Y e t a n o t h e r o b j e c t i o n to p l a t o n i s m is that it s e e m s i n e v i t a b l y to lead to s c e p t i c i s m w i t h r e s p e c t to o u r k n o w l e d g e of logic a n d m a t h e m a t i c s . F o r if p l a t o n i s m w e r e t r u e , w h a t r e a s o n c o u l d w e h a v e for t h i n k i n g that intellectual i n t u i t i o n is g e n e r a l l y reliable? It m i g h t b e c l a i m e d that w e h a v e j u s t t h e s a m e r e a s o n s h e r e a s w e h a v e for t h i n k i n g that s e n s e - p e r c e p t i o n is reliable, n a m e l y that t h e h y p o t h e s i s of reliability p r o v i d e s t h e b e s t overall e x p l a n a t i o n of t h e e x i s t e n c e a n d c o h e r e n c e of o u r b e l i e f s . B u t in fact o u r belief in p e r c e p t u a l reliability fits i n t o a n e x p l a n a t o r y n e t w o r k that is w h o l l y l a c k i n g in t h e c a s e of i n t u i t i o n of a b s t r a c t objects. For w e have beliefs about our perceptual apparatus

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itself, a n d its m o d e of o p e r a t i o n , that m e s h c l o s e l y w i t h o u r b e l i e f s a b o u t t h e p h y s i c a l w o r l d that w e p e r c e i v e . A n d t h e s e i n t u r n p r o v i d e t h e b e s t available e x p l a n a t i o n of t h e c o u r s e of o u r e x p e r i e n c e . ( T h e s e i d e a s will b e d e v e l o p e d m o r e fully in c h a p t e r s 11 a n d 12.) In c o n t r a s t , w e h a v e n o b e l i e f s a b o u t t h e s t r u c t u r e of o u r faculty of i n t u i t i o n or its m o d e of o p e r a t i o n . I n d e e d , t h e e x i s t e n c e of such a faculty r e m a i n s a b a r e h y p o t h e s i s . N o r c a n t h e h y p o t h e s i s of its reliability play a n y real e x p l a n a t o r y role. In p a r t i c u l a r , w e c a n n o t u s e it to e x p l a i n o u r s u c c e s s in b u i l d i n g b r i d g e s a n d a e r o p l a n e s (in w h i c h m a t h e m a t i c s p l a y s a significa n t p a r t ) , u n l e s s w e c a n s u p p o s e that t h e w a y t h i n g s are in t h e a b s t r a c t r e a l m c a n m a k e a d i f f e r e n c e to w h a t h a p p e n s in t h e p h y s i c a l r e a l m — w h i c h b r i n g s u s b a c k to t h e i n c o h e r e n t idea of a b s t r a c t o b j e c t s as c a u s e s o n c e a g a i n . In fact all w e n e e d to s u p p o s e is that m a t h e m a t i c a l calculation g i v e s u s a c c e s s to w h a t e v e r structural f e a t u r e s of t h e p h y s i c a l w o r l d u n d e r l i e o u r s u c c e s s in a c t i o n . T h e o n l y o t h e r o p t i o n available to a p l a t o n i s t , in e x p l a i n i n g o u r k n o w l e d g e of t h e a b s t r a c t r e a l m , is to c l a i m t h a t s u c h k n o w l e d g e is i n n a t e , b e i n g b r o u g h t t o c o n s c i o u s n e s s b y t h e activity of t h i n k i n g a n d r e a s o n i n g . T h e r e are t w o s u b t l y d i f f e r e n t v e r s i o n s of s u c h a n a c c o u n t . E i t h e r it c a n b e c l a i m e d that b e l i e f * a b o u t t h e a b s t r a c t r e a l m are a l r e a d y l a t e n t in u s prior to t h o u g h t a n d r e a s o n i n g . O r it c a n b e c l a i m e d that t h e faculty of r e a s o n itself h a s a c o n s t i t u e n t s t r u c t u r e , w h i c h is s u c h that its o p e r a t i o n g i v e s rise to b e l i e f s a b o u t t h e a b s t r a c t r e a l m . B u t t h e d i f f e r e n c e s b e t w e e n t h e s e t w o f o r m s of a c c o u n t n e e d n o t d e t a i n u s at this s t a g e . F o r in e i t h e r c a s e t h e idea is t h a t t h e r e is s o m e t h i n g i n n a t e in t h e h u m a n m i n d that m i r r o r s or d e p i c t s t h e n a t u r e of t h e a b s t r a c t r e a l m . S u c h a n a c c o u n t e n a b l e s a p l a t o n i s t to d o w i t h o u t t h e s u p p o s i t i o n of c a u s a l c o n t a c t b e t w e e n a n a b s t r a c t o b j e c t a n d t h e h u m a n m i n d , a n d this is a m a r k in its f a v o u r . B u t w e are still left w i t h t h e s a m e p r o b l e m of e x p l a i n i n g w h a t r e a s o n w e h a v e for s u p p o s i n g t h a t t h e m i r r o r i n g o r d e p i c t i n g is g e n e r a l l y a c c u r a t e . F o r s u p p o s e w e a l l o w that w e h a v e i n n a t e b e l i e f s a b o u t logic a n d m a t h e m a t i c s . If w e g r a n t t h e p l a t o n i c c o n c e p t i o n of t h e s u b j e c t - m a t t e r of t h e s e d i s c i p l i n e s , t h e n w h a t r e a s o n w o u l d w e h a v e f o r t h i n k i n g t h a t t h e b e l i e f s i n q u e s t i o n are g e n e r a l l y t r u e ?

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S i n c e w e h a v e n o i d e a h o w it is that t h e s e b e l i e f s m i g h t c o m e to b e i n n a t e , n o r a n y a c c o u n t of w h y t h e p r o c e s s that l e a d s t h e m to b e i n n a t e s h o u l d e n s u r e that t h e y m i r r o r t h e n a t u r e of t h e a b s t r a c t r e a l m , w e l o s e n o t h i n g in e x p l a n a t o r y p o w e r if w e s u p p o s e that o u r logical a n d m a t h e m a t i c a l beliefs are g e n e r a l l y false. ( W e shall r e t u r n to this p o i n t in g r e a t e r detail in c h a p t e r 10.) For a g a i n , w e c a n n o t a p p e a l to t h e practical s u c c e s s of o u r a p p l i c a t i o n s of logic a n d m a t h e m a t i c s as a r e a s o n for t h i n k i n g that o u r i n n a t e b e l i e f s are reliable, u n l e s s w e c a n also e x p l a i n h o w truth a b o u t t h e abstract r e a l m c o u l d m a k e a d i f f e r e n c e to t h e c o u r s e of e v e n t s in the p h y s i c a l w o r l d . B u t this w e a r e d e b a r r e d f r o m d o i n g , g i v e n that t h e idea of c a u s a l i n f l u e n c e of t h e a b s t r a c t on t h e p h y s i c a l is i n c o h e r e n t . It w o u l d a p p e a r , t h e n , that n e i t h e r t h e h y p o t h e s i s of a faculty of intuition n o r t h e h y p o t h e s i s of i n n a t e n e s s a r e c a p a b l e of e x p l a i n i n g h o w w e h a v e k n o w l e d g e of t h e abstract r e a l m (given t h e p l a t o n i s t ' s c o n c e p t i o n of it). W e t h e n face a c h o i c e of e i t h e r d e n y i n g that w e m a y h a v e r e a s o n a b l e b e l i e f s a b o u t logic a n d m a t h e m a t i c s , or of f i n d i n g s o m e a l t e r n a t i v e ( n o n - p l a t o n i c ) a c c o u n t of their s u b j e c t - m a t t e r . In c o n c l u s i o n : t h e r e are i n s u f f i c i e n t r e a s o n s for s u p p o s i n g p l a t o n i s m to b e t r u e . Y e t t h e r e are v e r y g o o d r e a s o n s for s u p p o s i n g it to b e f a l s e . F o r o u r a c c e p t a n c e of p l a t o n i s m w o u l d m e a n b o t h that w e c o u l d give n o a c c o u n t of t h e m a n n e r in w h i c h w e m i g h t o b t a i n k n o w l e d g e of t h e a b s t r a c t r e a l m a n d that w e c o u l d n o l o n g e r h o l d r e a s o n a b l e beliefs a b o u t logic a n d mathematics, which would purportedly concern such a realm. T h e e m p i r i c i s t c a s e a g a i n s t this f o r m of s u b s t a n t i v e a priori k n o w l e d g e ( a r g u a b l y t h e m o s t p l a u s i b l e f o r m , a s w e s a w at t h e b e g i n n i n g of t h e l a s t c h a p t e r ) is t h e r e f o r e a p o w e r f u l o n e .

4 The Empiricist Case against Nativism Fiiw e m p i r i c i s t s b e s i d e s L o c k e h a v e b o t h e r e d to p r e s e n t explicit a r g u m e n t s against nativism, mostly taking its falsity for g r a n t e d . In t h e p r e s e n t c h a p t e r I shall c o n s i d e r w h e t h e r L o c k e ' s c a s e is really p o w e r f u l e n o u g h to justify s u c h a n a t t i t u d e .

Locke on Innate K n o w l e d g e L o c k e ' s m a i n a r g u m e n t a g a i n s t the e x i s t e n c e of i n n a t e k n o w l e d g e in B o o k 1 of the Essay is that t h e v a r i o u s s u p p o s e d i n n a t e t r u t h s (for e x a m p l e , ' G o d e x i s t s ' a n d ' W h a t e v e r is, is') a r e not in fact u n i v e r s a l l y a s s e n t e d to. H e cites t h e e x a m p l e s of c h i l d r e n a n d m a d m e n , m a n y of w h o m will n o t a s s e n t to s u c h p r o p o s i t i o n s if t h e y a r e put to t h e m . L o c k e is t h e r e f o r e a s s u m i n g that i n n a t e k n o w l e d g e w o u l d , if it e x i s t e d , n e c e s s a r i l y h a v e to be p r e s e n t in e v e r y o n e , a n d also that it w o u l d h a v e to b e available to c o n s c i o u s n e s s from birth. A s w e shall s e e , b o t h of t h e s e a s s u m p t i o n s are false. T h e a r g u m e n t f r o m m a d m e n is certainly a b a d o n e . T o say that s o m e t h i n g is i n n a t e for h u m a n b e i n g s is to say that all n o r m a l m e m b e r s of t h e s p e c i e s will p o s s e s s it, n o t that all w i t h o u t e x c e p t i o n will d o s o . C o n s i d e r , for e x a m p l e , t h e fact of p o s s e s s i n g t e n t o e s . T h i s is surely a n i n n a t e f e a t u r e of h u m a n b e i n g s . B u t s o m e h u m a n s will in fact h a v e l e s s , a n d s o m e m o r e . S o m e m a y lose a toe in a n a c c i d e n t , a n d o c c a s i o n a l l y b a b i e s are b o r n w i t h a n extra t o e , or w i t h a toe m i s s i n g . S o t h e fact that m a d m e n ( w h o o n a n y a c c o u n t of t h e m a t t e r a r e n o t n o r m a l h u m a n b e i n g s ) lack s o m e k n o w l e d g e that t h e rest of u s p o s s e s s d o e s n o t s h o w t h a t s u c h k n o w l e d g e is n o t i n n a t e .

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T h e a r g u m e n t f r o m c h i l d r e n is also u n s o u n d , b u t n e e d s to b e h a n d l e d s o m e w h a t d i f f e r e n t l y . A n a t u r a l first r e s p o n s e to it w o u l d b e to claim that i n n a t e k n o w l e d g e m i g h t b e latent in c h i l d r e n — t h a t is to s a y : it is t h e r e , b u t n o t y e t available to c o n s c i o u s n e s s . L o c k e a n t i c i p a t e s this r e p l y , a n d r e s p o n d s by a d o p t i n g w h a t m i g h t b e called ' t h e p r i n c i p l e of m e n t a l t r a n s p a r e n c y ' . H e c l a i m s that t h e r e c a n n o t b e a n y t h i n g in the m i n d that t h e s u b j e c t is u n a w a r e of. But this principle is surely i n d e f e n s ible. N o r n e e d w e c o m m i t t h e a n a c h r o n i s m of a p p e a l i n g to F r e u d i a n t h e o r i e s of t h e u n c o n s c i o u s to s h o w as m u c h . For c o n s i d e r t h e e v e r y d a y p h e n o m e n o n of t e m p o r a r y m e m o r y loss. Y o u m a y k n o w that y o u k n o w y o u r m o t h e r ' s b i r t h d a y , but be u n a b l e for t h e m o m e n t to recall it. Then an h o u r later y o u m a y b e able to r e m e m b e r it a g a i n . If w e a c c e p t e d t h e principle of m e n t a l t r a n s p a r e n c y , w e s h o u l d h a v e to say that y o u started by h a v i n g t h e k n o w l e d g e of y o u r m o t h e r ' s b i r t h d a y , t h e n you lost it, a n d t h e n you acquired it again w i t h o u t a n y p r o c e s s of l e a r n i n g . T h i s is surely a b s u r d . R a t h e r , w e s h o u l d say that the k n o w l e d g e w a s in y o u t h r o u g h o u t , b u t that for a s h o r t period it w a s not a c c e s s i b l e to c o n s c i o u s n e s s . W h i l e L o c k e ' s explicit a r g u m e n t a g a i n s t latent i n n a t e k n o w l e d g e is i n a d e q u a t e , it m a y s e e m that h e h a s a valid p o i n t n e v e r t h e l e s s . For are w e really p r e p a r e d to a c c e p t that a n e w b o r n i n f a n t h a s its h e a d a l r e a d y s t o c k e d with a r a n g e of actual (if as y e t m e r e l y latent) k n o w l e d g e ? O n e w a y of d e v e l o p i n g this p o i n t is to n o t i c e that y o u c a n n o t h a v e k n o w l e d g e o f s o m e t h i n g u n l e s s y o u also b e l i e v e it. ( Y o u c a n n o t know that t h e Earth is g e t t i n g w a r m e r u n l e s s y o u at least believe that t h e E a r t h is g e t t i n g w a r m e r . ) A n d w h a t m a k e s a m e n t a l state a state of belief is that it is apt to interact with y o u r o t h e r m e n t a l s t a t e s (particularly d e s i r e s a n d i n t e n t i o n s ) in s u c h a w a y as to control b e h a v i o u r . T h u s , w h a t m a k e s t h e d i f f e r e n c e b e t w e e n believing that t h e E a r t h is g e t t i n g w a r m e r a n d hoping that it is, for e x a m p l e , is that y o u are p r e p a r e d if n e c e s s a r y to act o n it. Y o u m a y c o n s i d e r m o v i n g to I c e l a n d , or s t o p u s i n g a e r o s o l s ( d e p e n d i n g u p o n y o u r o t h e r b e l i e f s , a n d o n w h a t it is t h a t y o u w a n t ) . T h e n s i n c e a n i n f a n t c a n n o t m a n i f e s t a n y of t h e a p p r o p r i a t e b e h a v i o u r , it w o u l d s e e m that it c a n n o t h a v e articulate b e l i e f s e i t h e r .

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T h i s a r g u m e n t is p e r h a p s o v e r l y s w i f t , h o w e v e r . F o r e v e n if a n i n f a n t c a n n o t b e said to b e b o r n a l r e a d y p o s s e s s i n g b e l i e f s , it m a y b e that it is b o r n w i t h a s t o r e d s t o c k of propositions. T h e s e m a y start by b e i n g inert, b u t t h e n b e c o m e k n o w l e d g e as s o o n as t h e child is old e n o u g h to b e c o n s c i o u s of t h e m . Y e t e v e n this m a y strike o n e as an e x t r a o r d i n a r y h y p o t h e s i s . T h e idea that t h e h e a d of a n i n f a n t is a l r e a d y s t o c k e d w i t h a r a n g e of articulate p r o p o s i t i o n s m a y strike o n e (and d o e s strike m e ) a s j u s t wild. A t a n y r a t e , if this w e r e t h e o n l y f o r m that n a t i v i s m c o u l d t a k e , t h e n t h e b u r d e n of p r o o f w o u l d s u r e l y fall s q u a r e l y o n t h e nativist to p r o v i d e s o m e c o n v i n c i n g a r g u m e n t for t h e i r v i e w . L o c k e w o u l d b e quite right that t h e r e is a s t r o n g p r e s u m p t i o n a g a i n s t n a t i v i s m , u n l e s s a n d until w e a r e s h o w n o t h e r w i s e . In fact, h o w e v e r , t h e r e is q u i t e a d i f f e r e n t s e n s e in w h i c h i n n a t e k n o w l e d g e m a y b e l a t e n t f r o m b i r t h . F o r it m a y b e i n n a t e l y d e t e r m i n e d that c h i l d r e n d e v e l o p s u c h k n o w l e d g e at a certain s t a g e in the c o u r s e of their n o r m a l g r o w t h , i r r e s p e c t i v e of d e t a i l s of e d u c a t i o n a n d e x p e r i e n c e . C o m p a r e , for e x a m p l e , t h e p o s s e s s i o n of p u b i c hair. T h i s is s u r e l y a n i n n a t e f e a t u r e of a d u l t h u m a n b e i n g s . But it is n o t p r e s e n t f r o m b i r t h , o n l y m a k i n g its a p p e a r a n c e with t h e o n s e t of p u b e r t y . Similarly, t h e n , in t h e c a s e of k n o w l e d g e : it m a y b e that it is n o t p r e s e n t at all at birth ( t h e r e b e i n g n o s t o r e d s t o c k of p r o p o s i t i o n s ) , b u t that it is i n n a t e l y d e t e r m i n e d that s u c h k n o w l e d g e will m a k e its a p p e a r a n c e at s o m e particular s t a g e in n o r m a l c o g n i t i v e d e v e l opment. L o c k e h i m s e l f c o n s i d e r s i d e a s r e l a t e d to this o n e . F o r h e a r g u e s a g a i n s t t h e s u g g e s t i o n that t r u t h s m a y b e i n n a t e in t h e s e n s e that a child h a s a n i n n a t e capacity for k n o w i n g t h e m . H e also a r g u e s a g a i n s t t h e t h e s i s that i n n a t e k n o w l e d g e m a y m a k e its a p p e a r a n c e in the m i n d w h e n t h e s u b j e c t first a t t a i n s t h e u s e of r e a s o n . But his o n l y r e s p o n s e to t h e first s u g g e s t i o n is that o n e c a n n o t t h e n d i s t i n g u i s h b e t w e e n t r u t h s that a r e l e a r n e d a n d t r u t h s that are i n n a t e , if ' i n n a t e ' j u s t m e a n s that a child h a s a n i n n a t e c a p a c i t y to k n o w t h e m . W h i l e this m a y b e t r u e , if ' c a p a c i t y ' is u n d e r s t o o d b r o a d l y , it is n o t a n o b j e c t i o n to t h e d e v e l o p m e n t a l t h e s i s s k e t c h e d a b o v e . F o r if t h e t r u t h s that m a k e t h e i r a p p e a r a n c e s u b s e q u e n t u p o n e x p e r i e n c e could not have been learned from t h a t e x p e r i e n c e , t h e n this will b e s u f f i c i e n t r e a s o n t o c o u n t t h e m a s i n n a t e , as w e shall s e e i n t h e n e x t

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s e c t i o n . A n d a s for t h e s u g g e s t i o n that i n n a t e k n o w l e d g e m a y m a k e its a p p e a r a n c e w i t h t h e o n s e t of r e a s o n , L o c k e ' s r e s p o n s e is m o s t l y t o c h i p a w a y at this as a p r o p o s e d time at w h i c h i n n a t e k n o w l e d g e m i g h t a p p e a r , w h i c h in n o w a y t o u c h e s t h e g e n e r a l idea b e h i n d d e v e l o p m e n t a l n a t i v i s m .

Varieties of Innateness W e h a v e n o t e d that w h i l e o n e form of n a t i v i s m c l a i m s ( s o m e w h a t i m p l a u s i b l y ) that k n o w l e d g e is i n n a t e in t h e s e n s e of b e i n g p r e s e n t a s s u c h (or at least p r e s e n t in p r o p o s i t i o n a l f o r m ) f r o m b i r t h , it m i g h t also b e m a i n t a i n e d that k n o w l e d g e is i n n a t e in t h e s e n s e of b e i n g i n n a t e l y d e t e r m i n e d to m a k e its a p p e a r a n c e at s o m e s t a g e in c h i l d h o o d . T h i s latter t h e s i s is surely the m o s t p l a u s i b l e v e r s i o n of n a t i v i s m . I n d e e d , t h e r e s e e m s n o p a r t i c u l a r r e a s o n w h y w e s h o u l d p r e s u m e its f a l s e h o o d . For g i v e n that m u c h of t h e p h y s i c a l g r o w t h a n d d e v e l o p m e n t of h u m a n b e i n g s is i n n a t e l y d e t e r m i n e d , w h y s h o u l d t h e s a m e n o t b e true of o u r c o g n i t i v e d e v e l o p m e n t also? It is t h e r e f o r e n o t at all o b v i o u s t h a t t h e b u r d e n of p r o o f is o n t h e d e f e n d e r of this f o r m of n a t i v i s m to m a k e o u t their c a s e , r a t h e r t h a n on L o c k e to s h o w that all k n o w l e d g e is in fact a c q u i r e d f r o m e x p e r i e n c e . But w e s h o u l d n o w n o t i c e that this s e c o n d h y p o t h e s i s , in t u r n , admits of two alternative versions. First, a b e l i e f m i g h t b e i n n a t e in t h e s e n s e t h a t it is a c q u i r e d in a n y c o u r s e of e x p e r i e n c e sufficient for f o r m i n g b e l i e f s at all. T o a d o p t this h y p o t h e s i s is to allow (as s e e m s likely) that a n i n f a n t s e n s o r i l y d e p r i v e d f r o m birth w o u l d n e v e r h a v e a n y k n o w l e d g e or b e l i e f s , i n n a t e or o t h e r w i s e . W e w o u l d b e a l l o w i n g that s o m e initial e x p e r i e n c e is n e c e s s a r y for t h e m i n d to o p e r a t e n o r m a l l y , a n d for i n n a t e k n o w l e d g e to m a k e its a p p e a r a n c e . B u t w e w o u l d b e c l a i m i n g that it d o e s n o t m a t t e r what e x p e r i e n c e s t h e c h i l d h a s , p r o v i d e d that t h e y a r e sufficiently rich a n d v a r i e d for it to a c q u i r e at l e a s t s o m e b e l i e f s . L e t u s call this ' t h e h y p o t h e s i s of g e n e r a l t r i g g e r i n g of i n n a t e k n o w l e d g e ' — ' g e n e r a l t r i g g e r i n g ' b e c a u s e a l m o s t a n y e x p e r i e n c e will s e r v e , t h e c o n t e n t of t h e e x p e r i e n c e s n e e d i n g to b e a r n o r e l a t i o n w h a t e v e r t o t h e c o n t e n t of t h e i n n a t e b e l i e f s t h a t m a k e their a p p e a r a n c e a s a r e s u l t .

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T h e s e c o n d s e n s e in w h i c h a n a c q u i r e d b e l i e f m i g h t b e i n n a t e w o u l d b e if its e x i s t e n c e w e r e i n e x p l i c a b l e o n a n y m o d e l of l e a r n i n g , its c o n t e n t b e i n g s u c h that it c o u l d n o t h a v e b e e n l e a r n e d f r o m t h e e x p e r i e n c e s that g a v e rise to it. T o a d o p t this h y p o t h e s i s w o u l d b e to a l l o w , a s b e f o r e , that a s e n s o r i l y d e p r i v e d i n f a n t w o u l d n e v e r c o m e to h a v e a n y b e l i e f s . B u t it w o u l d also b e to a l l o w that quite specific t y p e s of e x p e r i e n c e m a y b e n e c e s s a r y for a g i v e n i n n a t e belief to m a k e its a p p e a r a n c e . For e x a m p l e , it m i g h t b e c l a i m e d (as w e shall s e e in c h a p t e r 6) that o u r k n o w l e d g e of g r a m m a t i c a l s t r u c t u r e is i n n a t e , b u t that s o m e e x p e r i e n c e of l a n g u a g e is n e c e s s a r y to trigger this k n o w l e d g e i n t o e x i s t e n c e . O r it m i g h t b e c l a i m e d (as w e shall s e e in c h a p t e r 8) that o u r k n o w l e d g e of t h e r u d i m e n t s of h u m a n p s y c h o l o g y is i n n a t e , b u t that s o m e e x p e r i e n c e o f o t h e r h u m a n s is n e c e s s a r y for it to m a k e its a p p e a r a n c e . ( S o Tar/.an, b r o u g h t u p by a p e s in the j u n g l e , w o u l d n e v e r a c q u i r e e i t h e r of t h e s e sorts of belief, a l t h o u g h h i s e x p e r i e n c e w o u l d b e sufficiently rich for h i m to h a v e m a n y o t h e r b e l i e f s . ) But t h e k n o w l e d g e in q u e s t i o n could still r e a s o n a b l y b e said to b e i n n a t e , p r o v i d e d that it is i m p o s s i b l e to s e e h o w it c o u l d h a v e b e e n learned on the b a s i s of the e x p e r i e n c e s in q u e s t i o n — f o r e x a m p l e , if n o c o m b i n a t i o n of m e m o r y , i n d u c t i o n , a n d infere n c e t o t h e b e s t e x p l a n a t i o n could h a v e g e n e r a t e d that k n o w ledge from such a meagre basis. Let u s call this s e c o n d v e r s i o n of d e v e l o p m e n t a l n a t i v i s m ' t h e h y p o t h e s i s of local t r i g g e r i n g of i n n a t e k n o w l e d g e ' — ' l o c a l ' b e c a u s e specific ( c o n t e n t - r e l e v a n t ) t y p e s of e x p e r i e n c e a r e n e c e s s a r y for t h e k n o w l e d g e to m a k e its a p p e a r a n c e , b u t still ' t r i g g e r i n g ' b e c a u s e t h e c o n t e n t of t h e k n o w l e d g e a c q u i r e d is s o related to t h e c o n t e n t of t h e e x p e r i e n c e s that give rise to it that t h e f o r m e r c o u l d n o t h a v e b e e n l e a r n e d f r o m t h e latter. M o s t of t h e a r g u m e n t s in s u p p o r t of n a t i v i s m that w e shall c o n s i d e r in later c h a p t e r s a r e in fact a r g u m e n t s for local t r i g g e r i n g . N o t i c e that L o c k e h i m s e l f p r o v i d e s n o direct a r g u m e n t s a g a i n s t e i t h e r of t h e s e f o r m s of d e v e l o p m e n t a l n a t i v i s m .

Locke o n C o n c e p t Acquisition T h e a r g u m e n t s c o n s i d e r e d a b o v e f r o m B o o k I of t h e Essay a r e n o t t h e o n l y o n e s that L o c k e u s e s a g a i n s t n a t i v i s m . I n d e e d , t h e y

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do n o t e v e n c o n s t i t u t e h i s m a i n a r g u m e n t . R a t h e r , h e t h i n k s that it will b e s u f f i c i e n t t o r e f u t e n a t i v i s m if it c a n b e s h o w n t h a t the h y p o t h e s i s of i n n a t e k n o w l e d g e is a n unnecessary o n e — t h a t is to s a y , if h e c a n p r o v i d e a n a l t e r n a t i v e a c c o u n t of t h e g e n e s i s of all k n o w l e d g e in e x p e r i e n c e . T h i s is his strategy t h r o u g h o u t the r e m a i n i n g t h r e e b o o k s of t h e Essay. N o w , a l t h o u g h I d e n i e d a b o v e that t h e r e is a g e n e r a l p r e s u m p t i o n a g a i n s t t h e t r u t h of n a t i v i s m (at least in e i t h e r of its m o r e p l a u s i b l e d e v e l o p m e n t a l v e r s i o n s ) , it d o e s s e e m to m e that L o c k e is o n s t r o n g g r o u n d h e r e . For s u p p o s e that b o t h L o c k e a n d t h e nativist c o u l d p r o v i d e e q u a l l y g o o d e x p l a n a t i o n s of the k n o w l e d g e w e actually p o s s e s s . In t h e c a s e of t h e nativist (but not of L o c k e ) t h e r e w o u l d still b e s o m e t h i n g left o v e r that n e e d e d e x p l a i n i n g — n a m e l y , h o w it is that s o m e of o u r k n o w l e d g e c o m e s t o b e i n n a t e . W e a l r e a d y k n o w that s o m e k n o w l e d g e is d e r i v e d f r o m e x p e r i e n c e , a n d w e k n o w r o u g h l y h o w this t a k e s p l a c e ( t h r o u g h p e r c e p t i o n ) . S o t h e h y p o t h e s i s that all k n o w l e d g e c o m e s f r o m e x p e r i e n c e l e a v e s n o t h i n g f u r t h e r in n e e d of e x p l a n a t i o n . In c o n t r a s t , if s o m e k n o w l e d g e is i n n a t e , it still r e m a i n s to b e e x p l a i n e d h o w it c o m e s to b e s o . T h e r e f o r e , o t h e r t h i n g s b e i n g e q u a l , L o c k e ' s h y p o t h e s i s is t h e o n e to b e p r e f e r r e d , s i n c e it l e a v e s l e s s in n e e d of e x p l a n a t i o n . In fact L o c k e d o e s n o t f o c u s v e r y directly o n e x p l a i n i n g t h e a c q u i s i t i o n of k n o w l e d g e f r o m e x p e r i e n c e . R a t h e r , m o s t of his efforts a r e d i r e c t e d t o w a r d s s h o w i n g h o w all o u r c o n c e p t s (ideas) m a y b e d e r i v e d f r o m e x p e r i e n c e . H e h e r e a s s u m e s , I t h i n k , t h a t n o k n o w l e d g e c a n b e i n n a t e if n o c o n c e p t s a r e . S o if h e can s h o w that t h e h y p o t h e s i s of i n n a t e concepts is a n u n n e c e s s a r y o n e , h e b e l i e v e s that h e will t h e r e b y h a v e s h o w n that t h e h y p o t h e s i s of i n n a t e k n o w l e d g e is also u n n e c e s s a r y . 1

T h e i d e a t h a t i n n a t e k n o w l e d g e r e q u i r e s i n n a t e c o n c e p t s is certainly a v e r y p l a u s i b l e o n e . F o r it is clearly t h e c a s e that k n o w l e d g e itself r e q u i r e s c o n c e p t s . K n o w l e d g e (at l e a s t in t h e s e n s e that c o n c e r n s u s ) is e s s e n t i a l l y p r o p o s i t i o n a l — i t is a l w a y s k n o w l e d g e that such-and-such is the case. S o y o u c a n n o t p o s s e s s s u c h k n o w l e d g e u n l e s s y o u also p o s s e s s t h e c o n c e p t s i n v o l v e d in t h e p r o p o s i t i o n that such-and-such. You cannot k n o w that g r a s s is g r e e n u n l e s s y o u p o s s e s s t h e c o n c e p t s grass a n d green. B u t in fact, w h e t h e r this d e p e n d e n c e of k n o w l e d g e u p o n 1

I n d e e d , s e e t h e Essay, b k . i, c h . iv, s e c t . 2 0 .

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c o n c e p t s e x t e n d s also to t h e d e p e n d e n c e of innate k n o w l e d g e u p o n innate c o n c e p t s t u r n s o n w h a t exact c o n c e p t of t h e i n n a t e is in q u e s t i o n . C l e a r l y t h e r e c a n b e n o i n n a t e k n o w l e d g e in t h e s e n s e of s t o r e d p r o p o s i t i o n s u n l e s s t h e r e a r e also i n n a t e c o n c e p t s . F o r t h e c o n s t i t u e n t c o n c e p t s of t h o s e p r o p o s i t i o n s will also h a v e to b e p r e s e n t in t h e m i n d f r o m birth if t h e p r o p o s i t i o n s t h e m s e l v e s a r e . N o r c a n t h e r e b e g e n e r a l t r i g g e r i n g of i n n a t e k n o w l e d g e b y e x p e r i e n c e u n l e s s t h e r e is also g e n e r a l t r i g g e r i n g of i n n a t e c o n c e p t s . For r e m e m b e r that t h e e x p e r i e n c e s that give rise to s u c h k n o w l e d g e n e e d b e a r n o relation to it in c o n t e n t , a n d s o w o u l d n o t b e the sort of e x p e r i e n c e f r o m w h i c h o n e c o u l d d e r i v e (that is, learn) the c o n c e p t s in q u e s t i o n e i t h e r . M a t t e r s a r e quite d i f f e r e n t , h o w e v e r , w h e n it c o m e s to t h e t h e s i s of local t r i g g e r i n g . F o r , on this a c c o u n t , it m a y b e that c o n c e p t s a r e l e a r n e d from a p p r o p r i a t e a n d r e l e v a n t e x p e r i e n c e , b u t a r e t h e n triggered into i t e m s of k n o w l e d g e that g o far b e y o n d t h e c o n t e n t of the e x p e r i e n c e s that g a v e rise to the c o n s t i t u e n t c o n c e p t s . It m a y t h u s b e that w h i l e n o c o n c e p t s a r e i n n a t e , s o m e k n o w l e d g e is. For it m a y b e that w h i l e t h e data that g i v e s rise to o u r k n o w l e d g e of s o m e s u b j e c t - m a t t e r is n o t sufficient to s u s t a i n t h e v i e w that w e a c q u i r e d that k n o w l e d g e t h r o u g h learning, it m a y still b e sufficient to s u p p o r t t h e v i e w that w e l e a r n e d t h e constituent concepts. T h u s L o c k e ' s a s s u m p t i o n that t h e r e c a n b e n o i n n a t e k n o w l e d g e w i t h o u t i n n a t e c o n c e p t s is f a l s e . In w h i c h c a s e his a r g u m e n t s a g a i n s t c o n c e p t - n a t i v i s m will n o t n e c e s s a r i l y u n d e r m i n e k n o w l e d g e - n a t i v i s m . N e v e r t h e l e s s , it is w o r t h c o n s i d e r i n g his t h e o r y of c o n c e p t a c q u i s i t i o n in its o w n r i g h t . F o r , a f t e r all, m o s t nativists h a v e in fact h e l d , n o t o n l y that s o m e k n o w l e d g e is i n n a t e , b u t a l s o that s o m e c o n c e p t s a r e . M o r e o v e r , t h e m o s t p l a u s i b l e c a s e of i n n a t e k n o w l e d g e , to b e d e f e n d e d in c h a p t e r 8 ( n a m e l y , k n o w l e d g e of t h e g e n e r a l p r i n c i p l e s g o v e r n i n g o u r o w n a n d o t h e r p e o p l e ' s p s y c h o l o g y ) , will in fact b e s u c h a s t o i n v o l v e t h e claim t h a t t h e r e a r e i n n a t e c o n c e p t s a l s o . Locke believes that w e derive simple concepts from experie n c e b y abstraction ( c o m p l e x c o n c e p t s c a n t h e n b e f o r m e d f r o m s i m p l e o n e s b y d e f i n i t i o n ) . T h e i d e a is t h a t f r o m a s e q u e n c e of e x p e r i e n c e s w e a r e to isolate t h e v a r i o u s f e a t u r e s t h e y h a v e i n c o m m o n . W e a r e t o d o t h i s b y i g n o r i n g d i f f e r e n c e s of t i m e ,

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context, and so on, a n d by noticing a n d isolating recurring a s p e c t s . C o n s i d e r this a n a l o g y . S u p p o s e t h a t y o u are t a k i n g p a r t in o n e of t h o s e p s y c h o l o g i c a l e x p e r i m e n t s w h e r e y o u are h a n d e d a s e q u e n c e of c a r d s o n w h i c h g e o m e t r i c a l s h a p e s of v a r y i n g c o l o u r s h a v e b e e n p r i n t e d . S o m e a r e red t r i a n g l e s , s o m e g r e e n t r i a n g l e s ; s o m e a r e b l u e c i r c l e s , s o m e red circles; a n d s o o n . A s y o u are h a n d e d e a c h c a r d t h e e x p e r i m e n t e r s a y s e i t h e r ' T h i s is a g r i n k ' or ' T h i s is n o t a g r i n k ' , y o u r task b e i n g to a c q u i r e t h e c o n c e p t grink. W h a t y o u w o u l d d o , of c o u r s e , w o u l d b e to a t t e m p t to s p o t r e s e m b l a n c e s b e t w e e n t h o s e c a r d s that c o n t a i n a g r i n k , u s i n g t h o s e that d o n o t t o c o n f i r m or r e f u t e y o u r h y p o t h e s e s . T h i s will b e h o w L o c k e t h i n k s of c o n c e p t a c q u i s i tion in g e n e r a l . F o r w h a t y o u w o u l d in effect b e d o i n g in this e x p e r i m e n t is a b s t r a c t i n g f r o m t h e s e q u e n c e of y o u r e x p e r i e n c e s t h e c o m m o n f e a t u r e of all g r i n k s . A s it s t a n d s , h o w e v e r , L o c k e ' s a c c o u n t of c o n c e p t acquisition a p p e a r s viciously circular. F o r n o t i c i n g or a t t e n d i n g to a c o m m o n feature of v a r i o u s t h i n g s p r e s u p p o s e s that you a l r e a d y p o s s e s s t h e c o n c e p t of t h e f e a t u r e in q u e s t i o n . T h u s in o r d e r to n o t i c e that P e t e r , P a u l , a n d M a r y h a v e s o m e t h i n g in c o m m o n — n a m e l y , that t h e y a r e all f r e c k l e d — y o u m u s t a l r e a d y p o s s e s s t h e c o n c e p t of b e i n g f r e c k l e d . ( T h i s is n o t to say that you m u s t a l r e a d y h a v e a word for ' f r e c k l e d ' ; b u t y o u m u s t k n o w in g e n e r a l h o w to d i s t i n g u i s h p e o p l e w h o a r e f r e c k l e d f r o m p e o p l e w h o a r e n o t . ) E v e n m o r e o b v i o u s l y , if o n e t h i n k s of c o n c e p t a c q u i s i t i o n as b e i n g a m a t t e r of f o r m u l a t i n g a n d t e s t i n g h y p o t h e s e s (for e x a m p l e , i s a g r i n k a n y f o u r - s i d e d figure that is e i t h e r r e d or g r e e n ? ' ) , t h e n s o m e c o n c e p t s m u s t a l r e a d y b e p o s s e s s e d in a d v a n c e ( n a m e l y , t h e c o n c e p t s that figure in t h e hypotheses). W h i l e L o c k e d i s c u s s e s a b s t r a c t i o n in t e r m s that s u g g e s t that t h e p r o c e s s e s i n v o l v e d will b e c o n s c i o u s o n e s , it w o u l d b e o p e n to h i m to r e s p o n d to t h e a b o v e o b j e c t i o n b y d e n y i n g t h i s . H e c o u l d s a y that his t h e o r y is really that prior to a c q u i r i n g a n y c o n c e p t s t h e r e a r e p r o c e s s e s that a r e somewhat like t h o s e of n o t i c i n g r e s e m b l a n c e s , i g n o r i n g d i f f e r e n c e s of c o n t e x t , a n d s o o n , o n l y that t h e y a r e n o n - c o n s c i o u s o n e s . T h i s s a v e s t h e a c c o u n t f r o m circularity. B u t n o t i c e that it n o w a p p a r e n t l y c o n c e d e s t h a t t h e r e are i n n a t e c o n c e p t s after all, s i n c e n o n conscious noticing of a resemblance presumably requires a

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n o n - c o n s c i o u s c o n c e p t of the feature in question. S o it is doubtful w h e t h e r L o c k e would find this d e f e n c e of his position satisfying. B u t h o w else is h e to d e f e n d it? W h i l e h e r e m a i n s w e d d e d to t h e l a n g u a g e of a b s t r a c t i o n , it a p p e a r s that h e m u s t b e c o m m i t t e d to t h e m i n d ' s p o s s e s s i o n of c o n s c i o u s or n o n - c o n s c i o u s c o n c e p t s prior to t h e p r o c e s s of a b s t r a c t i n g a c o n c e p t f r o m e x p e r i e n c e .

Complex Concepts If w e set a s i d e the w o r r y a b o u t circularity o u t l i n e d a b o v e , t h e n L o c k e ' s t h e o r y c a n s e e m q u i t e p o w e r f u l . In particular, it h a s the r e s o u r c e s to r e b u t m a n y of t h e a r g u m e n t s p r e s e n t e d by r a t i o n a l i s t s in f a v o u r of t h e t h e s i s that t h e r e a r e i n n a t e c o n c e p t s . In the Phaedo, for e x a m p l e , Plato a r g u e s that the c o n c e p t straight m u s t b e i n n a t e b e c a u s e , first, j u d g e m e n t s of ' a l m o s t straight' p r e s u p p o s e prior g r a s p of the c o n c e p t straight, a n d , s e c o n d l y , b e c a u s e no o b j e c t in t h e w o r l d of o u r e x p e r i e n c e can b e b e t t e r than a l m o s t straight. L o c k e can reply by d e n y i n g t h e implicit a s s u m p t i o n that straight is a s i m p l e i d e a , w h i c h w o u l d h a v e to b e l e a r n e d directly f r o m e x p e r i e n c e if it is l e a r n e d at all. R a t h e r , h e can say that w h a t w e d e r i v e f r o m e x p e r i e n c e is t h e c o m p a r a t i v e c o n c e p t straighter than, b y o b s e r v i n g pairs of u n e q u a l l y straight t h i n g s . W e c a n t h e n i n t r o d u c e t h e c o n c e p t straight by d e f i n i t i o n , as a t h i n g s t r a i g h t e r t h a n a n y t h i n g else could b e . L o c k e c a n reply similarly to D e s c a r t e s ' s a r g u m e n t in his third Meditation, that o u r c o n c e p t s of G o d ' s p e r f e c t i o n s m u s t b e i n n a t e , s i n c e t h e y plainly c o u l d n o t h a v e b e e n a c q u i r e d on the b a s i s of e x p e r i e n c e . L o c k e c a n m a i n t a i n that w h a t w e a c q u i r e from e x p e r i e n c e a r e t h e v a r i o u s c o m p a r a t i v e c o n c e p t s better than, more poiverful than, more knowledgeable than, a n d s o o n . T h e idea of G o d m a y t h e n b e i n t r o d u c e d b y d e f i n i t i o n , a s t h e o n e a n d o n l y p e r s o n w h o is b e t t e r , m o r e p o w e r f u l , a n d m o r e knowledgeable than anything else could possibly b e . H o w e v e r , L o c k e ' s a c c o u n t of c o n c e p t a c q u i s i t i o n d o e s face a n u m b e r of f u r t h e r difficulties. T h e m o s t n o t o r i o u s is that t h e r e a r e m a n y c o n c e p t s that c a n n o t b e a b s t r a c t e d directly f r o m e x p e r i e n c e , a n d y e t a p p e a r n o t to b e d e f i n a b l e in t e r m s that c a n b e s o a b s t r a c t e d e i t h e r . C o n s i d e r , f o r e x a m p l e , t h e c o n c e p t of

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c a u s a t i o n , w h i c h w a s t r e a t e d at l e n g t h b y H u m e . All that is i m m e d i a t e l y o b s e r v a b l e in a c a s e of A c a u s i n g B is that t h e o n e p r e c e d e s t h e o t h e r . H u m e s u g g e s t s that t h e r e m a i n d e r of o u r c o n c e p t is m a d e u p f r o m o b s e r v i n g r e g u l a r c o n c u r r e n c e s of s u c h e v e n t s . T h e n to say that A c a u s e d B will b e to say that it p r e c e d e d it, a n d that all e v e n t s of t h e s a m e type as A p r e c e d e e v e n t s of t h e s a m e t y p e as B . Y e t clearly this falls s h o r t of o u r intuitive c o n c e p t of a c a u s e , w h i c h i n c l u d e s t h e idea that c a u s e s s o m e h o w n e c e s s i t a t e their e f f e c t s . H u m e h a s to c o n c l u d e that this idea is an illusion, b r o u g h t a b o u t by o u r o w n h a b i t s of m i n d in e x p e c t i n g an e v e n t of t y p e B w h e n w e s e e o n e of t y p e A. S i n c e o u r p s y c h o l o g y is s u c h that w e c a n n o t avoid e x p e c t i n g B w h e n e v e r w e s e e A o c c u r , H u m e s u g g e s t s that w e m i s t a k e n l y a s s u m e that it is B itself that is u n a v o i d a b l e , g i v e n that A h a s o c c u r r e d . H e c l a i m s that w h a t w e d o is to p r o j e c t a feeling of p s y c h o l o g i c a l n e c e s s i t y on to t h e w o r l d . 2

T h e r e a r e m a n y r e a s o n s for r e j e c t i n g H u m e ' s a c c o u n t of the m a t t e r . O n e is that it tacitly a s s u m e s that w e d o h a v e a c o n c e p t of causal n e c e s s i t a t i o n , if o n l y as h o l d i n g b e t w e e n p s y c h o l o g i c a l e v e n t s . F o r w h a t , o t h e r w i s e , is t h e f e e l i n g of n e c e s s i t y a feeling of? A n o t h e r p o i n t is that o n e m a y c o m e to b e l i e v e in a causal r e l a t i o n s h i p b e t w e e n e v e n t s after o b s e r v i n g j u s t a single i n s t a n c e , w h e n t h e r e h a s b e e n n o o p p o r t u n i t y for a h a b i t of e x p e c t a t i o n to be f o r m e d . For e x a m p l e , I m a y s e e s o m e o n e fall d o w n s t a i r s a n d c o m e to b e l i e v e that this c a u s e d their b r o k e n leg, a l t h o u g h this is t h e first o c c a s i o n on w h i c h I h a v e o b s e r v e d a n y t h i n g of t h e sort to o c c u r . A n o t h e r a r g u m e n t is that w e m a y wonder whether A c a u s e d B , w h e r e this is clearly m o r e t h a n a m a t t e r o f w o n d e r i n g w h e t h e r all e v e n t s o f t y p e A p r e c e d e e v e n t s of t y p e B . Y e t in s u c h c a s e s w e a r e o b v i o u s l y n o t w o n d e r i n g w h e t h e r o u r m i n d s are n e c e s s i t a t e d to e x p e c t B g i v e n a n o b s e r v a t i o n of A . In fact w h a t is really i n v o l v e d in o u r idea of c a u s a t i o n a r e , at least, c o u n t e r f a c t u a l a n d s u b j u n c t i v e c o n d i t i o n a l s , a s w e h a v e a l r e a d y n o t e d in c h a p t e r 3. T o say that A c a u s e d B is t o i m p l y that if A had not h a p p e n e d , t h e n B would not have. It is also t o 3

S e e t h e Enquiry Treatise, b k . i, p t . m. 2

Concerning

Human

Understanding,

sects,

m-vn,

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the

T h e r e is just- o n e p a s s a g e in h i s w r i t i n g s w h e r e H u m e c o n c e d e s t h i s , w i t h o u t a p p a r e n t l y n o t i c i n g w h a t it is t h a t h e h a s d o n e . T h u s in t h e Enquiry 3

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i m p l y t h a t if in o t h e r sufficiently similar c i r c u m s t a n c e s a n e v e n t of t y p e A were to h a p p e n , t h e n a n e v e n t of t y p e B would h a p p e n a l s o . Y e t it is i m p o s s i b l e to s e e h o w t h e c o n c e p t s of s u c h c o n d i t i o n a l s m a y e i t h e r b e a b s t r a c t e d f r o m e x p e r i e n c e , or d e f i n e d purely in t e r m s that m a y b e s o a b s t r a c t e d . I n d e e d , it is a r g u a b l e that t h e r e is m o r e to t h e c o n c e p t of c a u s e e v e n t h a n this. D a v i d A r m s t r o n g , for e x a m p l e , m a i n t a i n s that c a u s a t i o n is b e s t u n d e r s t o o d a s a relation of n e c e s s i t a t i o n b e t w e e n i m m a n e n t u n i v e r s a l s . T h i s relation is h e l d to i m p l y , a n d h e n c e to e x p l a i n , the truth of t h e c o u n t e r f a c t u a l a n d s u b junctive conditionals mentioned above, rather than being c o n s t i t u t e d by t h e m . T h e n it is because A is m a d e u p of p r o p e r t i e s that n e c e s s i t a t e t h e p r o p e r t i e s m a k i n g u p B , that it is true that if A h a d n o t h a p p e n e d B w o u l d n o t h a v e , a n d a l s o true that if a n e v e n t similar to A w e r e to h a p p e n , s o w o u l d a n e v e n t similar to B . M o r e o v e r , A r m s t r o n g a r g u e s that t h e n o t i o n of causal n e c e s s i t a t i o n h a s to b e t a k e n a s p r i m i t i v e (that is, a s i n d e f i n a b l e ) . H e a l s o c o n c e d e s that it c a n n o t b e a c q u i r e d f r o m e x p e r i e n c e , w i t h o u t , I t h i n k , n o t i c i n g that h e is t h e r e f o r e c o m m i t t e d — v e r y p l a u s i b l y , in m y v i e w — t o t h e c l a i m that t h e c o n c e p t of c a u s e is i n n a t e . 4

O t h e r c o n c e p t s b e s i d e s c a u s a t i o n h a v e led to p r o b l e m s for classical e m p i r i c i s t s . T h u s b o t h B e r k e l e y a n d H u m e d r e w t h e c o n c l u s i o n that o u r c o n c e p t of m i n d - i n d e p e n d e n t , c o n t i n u o u s l y e x i s t i n g p h y s i c a l o b j e c t s is illusory, b e c a u s e t h e y w e r e (rightly) u n a b l e to s e e h o w s u c h a c o n c e p t c o u l d b e d e r i v e d f r o m e x p e r i e n c e , or d e f i n e d in t e r m s of c o n c e p t s t h a t c a n b e s o derived. Since one cannot have experience of an unexperienced o b j e c t , it is h a r d to s e e h o w o n e c o u l d d e r i v e t h e c o n c e p t of s u c h a n o b j e c t f r o m e x p e r i e n c e . But t h e n n e i t h e r c a n that c o n c e p t b e d e f i n e d in o t h e r t e r m s d e r i v a b l e f r o m e x p e r i e n c e . T h e c l o s e s t w e c o u l d get w o u l d b e to say that a n u n e x p e r i e n c e d o b j e c t is t h e c o n t i n u o u s l y e x i s t i n g cause of o u r e p i s o d i c e x p e r i e n c e s . B u t this is plainly too b r o a d (quite a p a r t f r o m t h e p r o b l e m of h o w w e a r e s u p p o s e d to h a v e a c q u i r e d t h e c o n c e p t of c a u s e ) . It c a n n o t Concerning Human Understanding, s e c t , vn, p t . n , h e r e p h r a s e s h i s d e f i n i t i o n of c a u s a l i t y b y s a y i n g 'if t h e first o b j e c t h a d n o t b e e n , t h e s e c o n d h a d n e v e r existed'. 4

S e e What is a Law of Nature?,

c h . 6.

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d i s t i n g u i s h b e t w e e n t h e c h a i r , as c a u s e of m y e x p e r i e n c e of it, and Descartes's all-powerful d e m o n . It is w o r t h r e m a r k i n g h e r e j u s t h o w p o w e r f u l l y t h e s e e m p i r i c i s t s m u s t h a v e b e e n c o n v i n c e d of the thesis that t h e r e a r e n o i n n a t e c o n c e p t s . F o r r a t h e r t h a n give u p this t h e s i s , t h e y w e r e p r e p a r e d to d e n y that it is p o s s i b l e for u s to c o n c e i v e of a m i n d - i n d e p e n d e n t p h y s i c a l reality. B u t in t h e a b s e n c e of a n y c o n v i n c i n g a r g u m e n t in its s u p p o r t , t h e p r o p e r c o n c l u s i o n to d r a w is s u r e l y that it is their a n t i - n a t i v i s m itself that is false.

Simple Concepts In fact p r o b l e m s arise for e m p i r i c i s t s e v e n in c o n n e c t i o n with the very s i m p l e s t c o n c e p t s , s u c h a s t h o s e of c o l o u r . For it is false that all i n s t a n c e s of a g i v e n c o l o u r s h a r e s o m e c o m m o n f e a t u r e . In w h i c h c a s e w e c a n n o t a c q u i r e t h e c o n c e p t of that c o l o u r by a b s t r a c t i n g t h e c o m m o n f e a t u r e of o u r e x p e r i e n c e . T h u s c o n sider t h e c o n c e p t red. D o all s h a d e s of red h a v e s o m e t h i n g in c o m m o n ? If s o , w h a t ? It is surely false that i n d i v i d u a l s h a d e s of r e d c o n s i s t , a s it w e r e , of t w o d i s t i n g u i s h a b l e e l e m e n t s : a g e n e r a l r e d n e s s t o g e t h e r w i t h a particular s h a d e . R a t h e r , r e d n e s s c o n s i s t s in a c o n t i n u o u s range of s h a d e s , e a c h of w h i c h is o n l y j u s t d i s t i n g u i s h a b l e f r o m its n e i g h b o u r s . A c q u i r i n g t h e c o n c e p t red is a m a t t e r of l e a r n i n g t h e e x t e n t of the r a n g e . N o r will it h e l p to s a y , a s B e r k e l e y d o e s , that t h e c o n c e p t of r e d is n o t a n i d e a of a c o m m o n f e a t u r e a b s t r a c t e d f r o m d i f f e r i n g r e d t h i n g s , b u t is r a t h e r a n i d e a of a particular s h a d e of r e d that is t h e n u s e d a s a r e p r e s e n t a t i v e of t h e w h o l e r a n g e . F o r t h e r e is n o t h i n g in t h e p a r t i c u l a r s h a d e itself that c a n give y o u t h e e x t e n t of t h e r a n g e . N o r c a n this b e l e a r n e d f r o m e x p e r i e n c e . T h e r e is n o t h i n g in experience t h a t c a n tell y o u w h e r e in t h e s p e c t r u m red b e g i n s a n d e n d s . It w o u l d s e e m t h a t t h e b o u n d a r i e s b e t w e e n the various colours m u s t s o m e h o w b e specified innately, unless t h e y c a n b e e x p l a i n e d a s t a u g h t social c o n s t r u c t s of s o m e k i n d . 5

T h i s last r e m a r k s u g g e s t s a n a l t e r n a t i v e s t r a t e g y t h a t is available to e m p i r i c i s t s for e x p l a i n i n g o u r p o s s e s s i o n of c o n c e p t s , a n d it is w o r t h c o n s i d e r i n g w h y t h e y h a v e n o t , i n g e n e r a l , b e e n i n c l i n e d t o p u r s u e it. T h e s t r a t e g y w o u l d b e to a p p e a l , n o t 5

See h i s I n t r o d u c t i o n t o The Principles

of Human

Knowledge.

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to a b s t r a c t i o n , b u t to s o m e sort of linguistic t r a i n i n g . W h y s h o u l d e m p i r i c i s t s n o t s a y , c o n s i s t e n t l y w i t h their a n t i - n a t i v i s m , that w e are taught t o classify t h i n g s in t h e w a y t h a t w e d o ? O n this v i e w , p o s s e s s i o n of c o n c e p t s w o u l d still arise o u t of e x p e r i e n c e by a p r o c e s s of l e a r n i n g . B u t t h e e x p e r i e n c e in q u e s t i o n w o u l d n o t b e (or n o t p r i m a r i l y ) of t h e t h i n g s to w h i c h t h e c o n c e p t s a p p l y , s o m u c h as of t h e n o r m s that a r e p r e v a l e n t in t h e p e r s o n ' s l a n g u a g e c o m m u n i t y . A c h i l d ' s first f u m b l i n g u s e of w o r d s w o u l d gradually b e r e f i n e d a n d p e r f e c t e d t h r o u g h a p r o c e s s of r e w a r d a n d c o r r e c t i o n . It w o u l d b e , for e x a m p l e , by m i s t a k e n l y d e s c r i b i n g a n u n r i p e t o m a t o as ' r e d ' , a n d b e i n g p u t right b y its p a r e n t s , that a child w o u l d a c q u i r e its g r a s p of t h e b o u n d a r i e s b e t w e e n the c o l o u r s . H o w e v e r , t h e o b v i o u s q u e s t i o n a r i s i n g for s u c h an a c c o u n t w o u l d b e this: f r o m w h e r e did o u r t e a c h e r s , in t u r n , a c q u i r e their c o n c e p t s ? T h e a n s w e r , in t e r m s of t h e t h e o r y , is e q u a l l y o b v i o u s : f r o m their t e a c h e r s . But n o w w e h a v e a p r o b l e m . Plainly t h e s e q u e n c e of p a s t t e a c h e r s c a n n o t b e infinite, s i n c e t h e h u m a n r a c e h a s n o t a l w a y s b e e n in e x i s t e n c e . S o it a p p e a r s that t h e r e m u s t h a v e b e e n s o m e p e r s o n , or g r o u p of p e o p l e , w h o w e r e t h e first to u s e s i m p l e c o n c e p t s , w i t h o u t h a v i n g b e e n t a u g h t to d o s o . B u t t h e n w e shall b e l a n d e d b a c k w i t h s o m e v e r s i o n of a b s t r a c t i o n i s m a g a i n , if w e a r e to a v o i d c o m m i t m e n t to n a t i v i s m . For t h o s e first u s e r s o f c o n c e p t s will s o m e h o w h a v e to h a v e a c q u i r e d their c o n c e p t s directly o n t h e b a s i s of their experience. Certainly the problem of concept acquisition cannot b e s o l v e d m e r e l y by p u s h i n g it b a c k i n t o t h e p a s t . It is for this r e a s o n ( a m o n g o t h e r s ) that m o s t e m p i r i c i s t s h a v e n o t t a k e n v e r y s e r i o u s l y t h e idea that w e a c q u i r e c o n c e p t s t h r o u g h linguistic t r a i n i n g . 6

W e s h o u l d , h o w e v e r , b e w a r e of t h e s u g g e s t i o n that t h e r e m u s t h a v e b e e n a first c o n c e p t - u s e r , if p r e s e n t c o n c e p t - u s e r s get their c o n c e p t s f r o m o t h e r s . F o r c o m p a r e t h e f o l l o w i n g . W h a t m a k e s s o m e o n e a m e m b e r of t h e h u m a n s p e c i e s ? O n e o b v i o u s a n s w e r is: b e i n g b o r n of h u m a n p a r e n t s . T h i s l o o k s e q u a l l y v u l n e r a b l e t o t h e c h a r g e of m e r e l y p u t t i n g a p r o b l e m off, o n t h e g r o u n d s that t h e r e m u s t h a v e b e e n at l e a s t t w o first h u m a n s A n o t h e r r e a s o n is t h a t m o s t e m p i r i c i s t s h a v e r e g a r d e d l a n g u a g e u s e a s s o m e h o w d e r i v a t i v e , n o t b e i n g d i r e c t l y i m p l i c a t e d in t h e p r o c e s s e s o f t h o u g h t . F o r a b r i e f c r i t i q u e of t h i s v i e w , s e e m y Tractarian Semantics, c h . 1 0 . 6

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w h o w e r e not h u m a n b y v i r t u e of h a v i n g h u m a n p a r e n t s . B u t in fact, as w e n o w k n o w , c r e a t u r e s that w e r e r e c o g n i z a b l y h u m a n e v o l v e d g r a d u a l l y , in small s t e p s , f r o m c r e a t u r e s that w e r e n o t . S o it is p o s s i b l e that s o m e t h i n g similar m a y hold in the c a s e of c o n c e p t acquisition as w e l l . It m a y b e that w h a t w a s r e c o g n i z a b l y a u s e of c o n c e p t s e v o l v e d g r a d u a l l y , f r o m t h e u s e of g r u n t s a n d g r o w l s that w e r e plainly n o n - c o n c e p t u a l . In w h i c h c a s e a n e m p i r i c i s t c o u l d e x p l a i n c o n c e p t a c q u i s i t i o n in t e r m s of linguistic t r a i n i n g , w i t h o u t h a v i n g to b e c o m m i t t e d to s o m e form of a b s t r a c t i o n i s m in e x p l a i n i n g h o w t h e first c o n c e p t s w e r e a c q u i r e d . But this is, s o far, m e r e l y a p r o m i s e . It r e m a i n s for a n empiricist to s h o w h o w c o n c e p t s could arise g r a d u a l l y out of s o m e t h i n g n o n - c o n c e p t u a l . W e shall r e t u r n to t h e i s s u e in c h a p t e r 7. F o r t h e m o m e n t , it is e n o u g h to h a v e n o t e d t h e w e a k n e s s e s in t h e classical e m p i r i c i s t a c c o u n t s of c o n c e p t acquisition.

W h y be Anti-Nativist? W h i l e t h e e m p i r i c i s t c a s e a g a i n s t p l a t o n i s m is p o w e r f u l , as w e s a w in c h a p t e r 3 , its c a s e a g a i n s t n a t i v i s m is v e r y w e a k b y c o m p a r i s o n . N o t o n l y a r e t h e direct a r g u m e n t s a g a i n s t n a t i v i s m u n s o u n d , b u t t h e a t t e m p t to e x p l a i n h o w all c o n c e p t s m a y arise out of e x p e r i e n c e itself f a c e s s e v e r e difficulties. T h i s is n o t to s a y , of c o u r s e , that n a t i v i s m is t h e n s h o w n to b e t r u e . It is s i m p l y that t h e c a s e a g a i n s t it is u n p r o v e n . W e m a y t h e n r e m a i n p u z z l e d as to w h y e m p i r i c i s t s s u c h as L o c k e a n d H u m e s h o u l d h a v e b e e n s o c o n v i n c e d , n e v e r t h e l e s s , that n a t i v i s m m u s t b e false. It m i g h t b e replied that t h e r e is n o special p r o b l e m a b o u t t h i s : t h e y w e r e s i m p l y m i s l e d b y b a d a r g u m e n t s . B u t I f i n d this r e s p o n s e u n s a t i s f y i n g . A f t e r all, L o c k e a n d H u m e w e r e b o t h e x t r e m e l y i n t e l l i g e n t m e n . S o it r e m a i n s p o s s i b l e , at least, t h a t t h e y m a y h a v e h a d o t h e r , m o r e p o w e r f u l , r e a s o n s for r e j e c t i n g n a t i v i s m . P e r h a p s t h e s e m a y h a v e g o n e u n m e n t i o n e d as a r e s u l t of s o m e sort of political e x p e d i e n c y . F o r e x a m p l e , it m a y h a v e b e e n that their real r e a s o n s w o u l d h a v e p l a c e d t h e m in direct o p p o s i t i o n to t h e C h u r c h .

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T h u s , o n e h y p o t h e s i s m i g h t b e t h a t t h e early e m p i r i c i s t s ' r e j e c t i o n of n a t i v i s m w a s part of t h e i r m o r e g e n e r a l E n l i g h t e n m e n t belief in t h e perfectability of m a n , a n d s h o u l d b e s e e n in c o n t r a s t w i t h t h e traditional C h r i s t i a n d o c t r i n e of original s i n . But this p r o p o s a l is h a r d l y v e r y s a t i s f a c t o r y e i t h e r , s i n c e t h e r e is n o intrinsic c o n n e c t i o n b e t w e e n perfectability a n d anti-nativism. E n l i g h t e n m e n t t h i n k e r s c o u l d e q u a l l y well h a v e m a i n t a i n e d t h a t w h i l e w e h a v e i n n a t e l y g i v e n k n o w l e d g e , a n d i n n a t e faculties that a r e s t r u c t u r e d in s u c h a w a y as to e m b o d y i n f o r m a t i o n about the world, our knowledge and attitudes nevertheless a d m i t of i n d e f i n i t e e x t e n s i o n a n d i m p r o v e m e n t . It is true that if t h e m i n d w e r e literally a ' b l a n k s l a t e ' , a s t h e early e m p i r i c i s t s s e e m e d to m a i n t a i n , t h e n h u m a n n a t u r e w o u l d b e a l m o s t u n l i m i t e d l y m a l l e a b l e , for g o o d or ill. T h e o n l y c o n s t r a i n t s w o u l d b e t h o s e of c a p a c i t y ( t h e r e m a y b e limits to h o w m u c h k n o w l e d g e a h u m a n m i n d c a n c o n t a i n , for e x a m p l e ) , a n d t h o s e i m p o s e d by t h e p r o p e r t i e s of t h e m e n t a l m e d i u m itself ( s o m e s o r t s of k n o w l e d g e m i g h t b e m o r e difficult to a c q u i r e o n t h e b a s i s of g e n e r a l l e a r n i n g p r i n c i p l e s , for e x a m p l e ) . S o t h e d e n i a l of n a t i v i s m , if c o r r e c t , w o u l d p r o v i d e s o m e sort of g u a r a n t e e of h u m a n perfectability. E n d o r s e m e n t s o f n a t i v i s m , in c o n t r a s t , w o u l d a d m i t of at least t w o p o s s i b l e v e r s i o n s , i m p l y i n g e i t h e r perfectability o n t h e o n e h a n d , or i n h e r e n t i m p e r f e c t i o n o n t h e o t h e r . B u t e v e n g i v e n a prior c o m m i t m e n t to p e r f e c t a b i l i t y , this w o u l d b e a v e r y p o o r r e a s o n for r e j e c t i n g n a t i v i s m a l t o g e t h e r . F o r it is j u s t as p l a u s i b l e that t h e e x p l a n a t i o n of perfectability m i g h t b e a n i n n a t e l y g i v e n but indefinitely improvable nature. Moreover, the current p r o p o s a l w o u l d r e q u i r e u s to a t t r i b u t e t o e m p i r i c i s t s a belief in h u m a n perfectability that is a p p a r e n t l y l a c k i n g in i n d e p e n d e n t s u p p o r t , b u t that s t a n d s in n e e d of it. F o r t h e y c a n n o t s i m p l y t a k e for g r a n t e d t h e falsity of C h r i s t i a n v e r s i o n s of n a t i v i s m , u n l e s s t h e y h a v e s o m e i n d e p e n d e n t r e a s o n for r e j e c t i n g n a t i v ism as such. A r a t h e r d i f f e r e n t sort of p r o p o s a l w o u l d b e t h a t t h e early e m p i r i c i s t s ' r e a s o n s for r e j e c t i n g n a t i v i s m m i g h t h a v e f o r m e d s u c h a f u n d a m e n t a l p a r t of their o u t l o o k a s n e v e r to h a v e b e e n c o n s c i o u s l y a r t i c u l a t e d . C e r t a i n l y it is c o m m o n e n o u g h in p h i l o s o p h y for t h i n k e r s to a l l o w t h e m s e l v e s to o v e r l o o k t h e w e a k n e s s e s in t h e i r explicit a r g u m e n t s f o r a t h e s i s , p r e c i s e l y

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b e c a u s e t h e y h a v e a l r e a d y b e c o m e c o n v i n c e d of t h e t r u t h of t h a t t h e s i s o n o t h e r , a n d l e s s readily articulable, g r o u n d s . C h a r i t y r e q u i r e s u s to h o p e that s o m e t h i n g of this sort m a y b e t r u e in c o n n e c t i o n w i t h t h e classical e m p i r i c i s t r e j e c t i o n o f n a t i v i s m . I shall r e t u r n to t h e i s s u e in t h e n e x t c h a p t e r , a n d a g a i n in c h a p t e r 9.

5 Is Innate Knowledge even Possible? IN this c h a p t e r I shall c o n s i d e r v a r i o u s p r o p o s e d a c c o u n t s of t h e c o n c e p t of k n o w l e d g e , a n d h o w t h e y b e a r on t h e q u e s t i o n w h e t h e r i n n a t e k n o w l e d g e is p o s s i b l e .

A Justificationalist A r g u m e n t In c h a p t e r 4 w e looked at L o c k e ' s r e a s o n s for d e n y i n g that t h e r e is in fact a n y i n n a t e k n o w l e d g e , a n d f o u n d t h e m w a n t i n g . S o m e p e o p l e h a v e t h o u g h t that h e a l s o h a d available to h i m a k n o c k d o w n p r o o f of t h e impossibility o f i n n a t e k n o w l e d g e , d e r i v i n g f r o m t h e c o n c e p t of k n o w l e d g e itself. B u t in fact this a r g u m e n t d e p e n d s u p o n a n a c c o u n t of t h e c o n c e p t that is p r o b a b l y i n c o r r e c t . M o r e o v e r , that L o c k e did n o t e m p l o y s u c h a n a r g u m e n t is e v i d e n c e that he c o n c e i v e d o f k n o w l e d g e s o m e w h a t d i f f e r e n t l y , in a w a y that w o u l d a l l o w i n n a t e k n o w l e d g e to b e p o s s i b l e in p r i n c i p l e ( e v e n if it is n o t a c t u a l ) . I shall first e x p l a i n t h e c o n c e p t i o n of k n o w l e d g e f r o m w h i c h t h e a r g u m e n t d e r i v e s , a n d t h e n d e v e l o p t h e a r g u m e n t itself. I shall a r g u e later that the a c c o u n t of k n o w l e d g e in q u e s t i o n is i n c o r r e c t . M a n y h a v e h e l d that k n o w l e d g e c a n b e d e f i n e d as j u s t i f i e d t r u e belief. T h a t is to s a y : in o r d e r to c o u n t as k n o w i n g s o m e t h i n g , y o u m u s t at least believe it, w h a t y o u b e l i e v e m u s t in fact b e true, a n d y o u m u s t h a v e sufficiently g o o d reasons for y o u r belief. S u c h a n a c c o u n t is n o t w i t h o u t its a t t r a c t i o n s . It is, for e x a m p l e , c a p a b l e of e x p l a i n i n g w h y s o m e o n e w h o ' p l a y s a h u n c h ' t h a t a p a r t i c u l a r h o r s e will w i n a r a c e d o e s n o t k n o w that it will w i n , e v e n t h o u g h t h e h o r s e d o e s in fact w i n j u s t as t h e y b e l i e v e d t h a t it w o u l d . F o r s u c h a p e r s o n h a s i n s u f f i c i e n t r e a s o n f o r their belief; r a t h e r , it w a s a m e r e g u e s s . T h e a c c o u n t c a n also

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e x p l a i n w h y s o m e o n e w h o h a s e x c e l l e n t r e a s o n s for their belief still d o e s n o t h a v e k n o w l e d g e , if it s h o u l d t u r n out f r o m a n o t h e r , or later, p e r s p e c t i v e that t h e i r belief is n o t in fact t r u e . F o r e x a m p l e , e v e n s o m e o n e w h o h a s j u s t d o p e d all t h e o t h e r h o r s e s in t h e race d o e s n o t h a v e k n o w l e d g e that t h e r e m a i n i n g c a n d i d a t e will w i n , if it s h o u l d t u r n o u t , t h r o u g h s o m e b i z a r r e s e q u e n c e of a c c i d e n t s , that o n e of t h e o t h e r s d o e s . ( W e c a n l e a v e o p e n , h e r e , t h e q u e s t i o n of j u s t h o w p o w e r f u l t h e r e a s o n s for b e l i e v i n g s o m e truth w o u l d h a v e to b e , in o r d e r to c o u n t as 'sufficiently g o o d ' to qualify that belief as k n o w l e d g e . For e s s e n t i a l l y t h e s a m e i s s u e — o f t h e d e g r e e of g r o u n d ing r e q u i r e d for k n o w l e d g e — a r i s e s in c o n n e c t i o n w i t h e a c h of t h e v a r i o u s c a n d i d a t e a c c o u n t s of t h e c o n c e p t that w e shall b e c o n s i d e r i n g . In fact I a m i n c l i n e d to t h i n k t h a t t h e s t a n d a r d s f o r a belief to c o u n t as k n o w l e d g e are p u r p o s e - r e l a t i v e , v a r y i n g d e p e n d i n g u p o n w h a t is at i s s u e in t h e c o n t e x t in q u e s t i o n . W h a t c o u n t s as k n o w l e d g e in r e s p o n s e to a c a s u a l e n q u i r y m a y n o t c o u n t a s k n o w l e d g e in a c o u r t of l a w , w h e r e s o m e o n e ' s life m a y h a n g in t h e b a l a n c e . S o I s u g g e s t that 'sufficiently g o o d ' m i g h t m e a n ' g o o d e n o u g h for t h e p u r p o s e s in h a n d ' . I shall r e t u r n to this idea in c h a p t e r 11.) If k n o w l e d g e is j u s t i f i e d t r u e belief, t h e n an i n n a t e belief c a n c o u n t as i n n a t e k n o w l e d g e o n l y if it h a s a justification t h a t is also i n n a t e . T h i s is b e c a u s e , in o r d e r for s o m e o n e to k n o w s o m e t h i n g o n this a c c o u n t , it is n o t e n o u g h that t h e r e s h o u l d be a j u s t i f i c a t i o n . R a t h e r , t h e p e r s o n in q u e s t i o n m u s t p o s s e s s that justification. For consider the following example. Playing a h u n c h , I d e c i d e that t h e h o r s e in t h e r e d a n d g r e e n c o l o u r s will w i n t h e r a c e . B u t , u n k n o w n to m e , t h e r e is in fact a s o u n d justification for m y c h o i c e — t h a t h o r s e h a s w o n all of h e r last t e n r a c e s , w h e r e a s t h e rest of t h e field h a v e j u s t b e e n d o p e d . E v e n s u p p o s i n g that m y h o r s e d o e s in fact w i n , I s u r e l y did n o t k n o w that s h e w o u l d . F o r I w a s j u s t g u e s s i n g , a n d t h a t is n o b a s i s for k n o w l e d g e o n a n y a c c o u n t of t h e m a t t e r . S o e v e n if t h e r e are i n n a t e b e l i e f s , t h e y will n o t c o u n t a s i n n a t e k n o w l e d g e if t h e evidence supporting them only emerges from subsequent experience. Y o u r r e a s o n s for a b e l i e f will p r e s u m a b l y c o n s i s t , i n g e n e r a l , of o t h e r b e l i e f s . If y o u h a v e a r e a s o n for b e l i e v i n g that w o r l d d e f o r e s t a t i o n will b e d i s a s t r o u s , t h e n this m u s t c o n s i s t in s o m e

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o t h e r b e l i e f or b e l i e f s t h a t i m p l y or o t h e r w i s e s u p p o r t that b e l i e f . A n d t h e s e b e l i e f s , i n their t u r n , m u s t b e j u s t i f i e d if t h e original b e l i e f is to b e j u s t i f i e d . F o r y o u c a n n o t p r o v i d e j u s t i f i c a t i o n for a belief t h r o u g h b e l i e f s t h a t are t h e m s e l v e s u n j u s t i f i e d . S o it l o o k s a s if w e h a v e a r e g r e s s : in o r d e r for o n e i n n a t e belief to b e i n n a t e l y k n o w n , t h e r e m u s t b e s o m e o t h e r i n n a t e belief that j u s t i f i e s it; a n d t h i s in t u r n m u s t h a v e a j u s t i f i c a t i o n that is also i n n a t e , a n d s o o n to i n f i n i t y . In w h i c h c a s e i n n a t e k n o w l e d g e is i m p o s s i b l e . F o r w e s u r e l y c a n n o t h a v e infinitely m a n y i n n a t e beliefs. It m i g h t b e said that this r e g r e s s c o u l d t e r m i n a t e w i t h beliefs t h a t a r e self-evident, that p r o v i d e their o w n j u s t i f i c a t i o n . T h i s m a y b e s o . B u t in fact t h e r e a r e o n l y t w o s o r t s of belief that a r e p l a u s i b l e c a n d i d a t e s for s u c h s e l f - e v i d e n c e , a n d n e i t h e r of t h e s e k i n d s will b e i n n a t e . First, a belief m a y b e s e l f - e v i d e n t in v i r t u e of c o n c e r n i n g t h e s u b j e c t ' s o w n i m m e d i a t e e x p e r i e n c e s ( s u c h as t h e b e l i e f that I n o w feel a p a i n ) . B u t in this sort of c a s e it w o u l d b e a b s u r d t o s u p p o s e that t h e b e l i e f in q u e s t i o n is i n n a t e . S e c o n d l y , s i m p l e t r u t h s of r e a s o n m a y b e s e l f - e v i d e n t , s u c h a s t h e belief t h a t 2 + 2 = 4 . B u t i n fact s u c h b e l i e f s will o n l y c o u n t as self-justified if t h e y c o n c e r n n o t h i n g b e y o n d t h e m s e l v e s (that is, if t h e y are analytic). F o r , in this c o n t e x t , s e l f - e v i d e n c e c a n n o t b e m e r e l y a m a t t e r of a belief striking u s a s intuitively o b v i o u s , s i n c e t h e r e w o u l d r e m a i n t h e q u e s t i o n of w h a t r e a s o n t h e r e is for t h i n k i n g that s u c h o b v i o u s n e s s is a g o o d g u i d e to t h e s t a t e of t h e w o r l d in q u e s t i o n . T o s e e t h i s , s u p p o s e t h a t t h e s u b j e c t - m a t t e r of t h e p r o p o s i t i o n '2 + 2 = 4 ' is c o n s t r u e d p l a t o n i s t i c a l l y , as c o n c e r n i n g n e c e s s a r i l y existing abstract individuals. A l t h o u g h this proposition m a y s e e m to u s u n d e n i a b l e , this is in fact i n s u f f i c i e n t for it to c o u n t a s s e l f - j u s t i f y i n g . F o r w h a t r e a s o n h a v e w e for s u p p o s i n g t h a t o b v i o u s n e s s - t o - u s (a f e a t u r e of o u r p s y c h o l o g y ) is a g o o d g u i d e to t h e w a y t h i n g s really a r e in t h e a b s t r a c t r e a l m ? If w e lack a n y r e a s o n for this belief, t h e n t h e p r o p o s i t i o n will n o t really b e j u s t i f i e d , d e s p i t e o u r inability to d e n y it. A n d if w e p o s s e s s s u c h a r e a s o n , t h e n t h e j u s t i f i c a t i o n for t h e p r o p o s i t i o n will d e r i v e f r o m s o m e o t h e r b e l i e f of o u r s , a n d t h e r e g r e s s will c o n t i n u e . S o i n n a t e s e l f - e v i d e n t p r o p o s i t i o n s c a n o n l y h a l t t h e r e g r e s s if t h e i r s u b j e c t - m a t t e r c o n c e r n s n o t h i n g b e y o n d t h e m s e l v e s (that i s , if they are analytic).

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W h a t this a r g u m e n t a p p e a r s to s h o w is t h a t it is i m p o s s i b l e t h a t t h e r e s h o u l d b e i n n a t e k n o w l e d g e t h a t is at t h e s a m e t i m e s u b s t a n t i v e (that c o n c e r n s a reality that is i n d e p e n d e n t of o u r m i n d s ) . T h i s is n o t quite t h e s a m e as s a y i n g t h a t i n n a t e k n o w l e d g e is i m p o s s i b l e a l t o g e t h e r . B u t in fact, g i v e n a n y d e v e l o p m e n t a l c o n s t r u a l of i n n a t e n e s s ( t w o v e r s i o n s of w h i c h w e r e o u t l i n e d in c h a p t e r 4 ) , that a belief is a n a l y t i c will u n d e r c u t all w a r r a n t for s u p p o s i n g it to b e i n n a t e . O n l y if w e w e r e p r e p a r e d to b e l i e v e that a n a l y t i c p r o p o s i t i o n s a r e s t o r e d in t h e m i n d as s u c h f r o m birth c o u l d w e a c c e p t that t h e r e is i n n a t e k n o w l e d g e of a n y sort, if t h e a r g u m e n t a b o v e is s o u n d . T h e reason w h y acquired analytic beliefs would not be c o u n t e d a s i n n a t e is t h a t t h e r e will b e n o p r o b l e m in e x p l a i n i n g h o w people might c o m e to possess t h e m through general l e a r n i n g m e c h a n i s m s . S i n c e k n o w l e d g e of s i m p l e ( s e l f - e v i d e n t ) a n a l y t i c t r u t h s r e q u i r e s o n l y that w e b e c a p a b l e of d i s c e r n i n g s i m p l e r e l a t i o n s b e t w e e n o u r o w n c o n c e p t s ( i d e a s ) , t h e r e will b e i n s u f f i c i e n t r e a s o n for s a y i n g that t h e k n o w l e d g e in q u e s t i o n is i n n a t e . E v e n if t h e c o n s t i t u e n t c o n c e p t s are i n n a t e , o u r k n o w l e d g e of t h e r e l a t i o n s b e t w e e n t h e m n e e d n o t b e . F o r in o r d e r to e x p l a i n h o w w e c o m e to p o s s e s s s u c h k n o w l e d g e , w e o n l y n e e d to s u p p o s e that w e h a v e t h e g e n e r a l ability to c o m p a r e a n d contrast our o w n ideas.

A Coherentist Suggestion It s h o u l d b e n o t e d t h a t t h e a r g u m e n t d e v e l o p e d a b o v e a g a i n s t t h e possibility of i n n a t e k n o w l e d g e p r e s u p p o s e s t h e t r u t h of f o u n d a t i o n a l i s m in t h e t h e o r y of k n o w l e d g e . F o r it a s s u m e s that t h e j u s t i f i c a t i o n - r e l a t i o n b e t w e e n beliefs is a linear o n e . T h e a r g u m e n t t a k e s f o r g r a n t e d that o n e b e l i e f will b e j u s t i f i e d b y a n o t h e r , w h i c h is j u s t i f i e d b y a n o t h e r , a n d s o o n u n t i l w e r e a c h b e l i e f s t h a t s o m e h o w j u s t i f y t h e m s e l v e s ( e i t h e r r e p o r t s of i m m e d i a t e e x p e r i e n c e or s i m p l e a n a l y t i c t r u t h s ) , t h e s e latter b e l i e f s c o n s t i t u t i n g t h e f o u n d a t i o n f o r t h e r e s t . B u t w h a t if w e w e r e to e m b r a c e a c o h e r e n t i s t a c c o u n t of j u s t i f i c a t i o n i n s t e a d ? W h a t if w e w e r e t o t a k e t h e v i e w t h a t a belief m a y b e j u s t i f i e d b y v i r t u e of f o r m i n g p a r t o f a m u t u a l l y s u p p o r t i n g n e t w o r k o f b e l i e f s , e a c h m e m b e r o f w h i c h r e c e i v e s its j u s t i f i c a t i o n f r o m its

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r e l a t i o n s h i p w i t h t h e o t h e r s ? T h i s w o u l d b e to p i c t u r e k n o w l e d g e , n o t a s a p y r a m i d built o n s e c u r e f o u n d a t i o n s , b u t r a t h e r a s a w e b h e l d t o g e t h e r b y t h e r e l a t i o n s h i p s b e t w e e n its c o m p o n e n t p a r t s . If this a c c o u n t w e r e a d e q u a t e , t h e n t h e r e would be no reason w h y we could not possess innate knowl e d g e . F o r w e m i g h t b e b o r n w i t h (or b o r n d e t e r m i n e d to d e v e l o p ) a set of c o n s i s t e n t a n d m u t u a l l y s u p p o r t i n g b e l i e f s o n s o m e s u b j e c t - m a t t e r . In w h i c h c a s e , p r o v i d e d t h a t t h o s e b e l i e f s w e r e t r u e , w e c o u l d b e said to h a v e i n n a t e k n o w l e d g e . F o r g i v e n a c o h e r e n t i s t c o n c e p t i o n of j u s t i f i c a t i o n , t h o s e i n n a t e b e l i e f s would not only be true but justified. C o h e r e n t i s m f a c e s c o n s i d e r a b l e difficulties if t a k e n at f a c e v a l u e , h o w e v e r . For t h e r e m a y b e a n y n u m b e r of c o h e r e n t b o d i e s o f b e l i e f s that a r e m u t u a l l y i n c o n s i s t e n t w i t h o n e a n o t h e r . F o r e x a m p l e , s u p p o s e that b o t h C h r i s t i a n i t y a n d Hinduism are internally coherent. Yet they cannot both be true, s i n c e t h e r e c a n n o t b e b o t h o n e G o d a n d m a n y . B u t in that c a s e it is v e r y h a r d i n d e e d to s e e h o w t h e m e r e fact of t h e c o h e r e n c e o f C h r i s t i a n belief c o u l d r e n d e r it j u s t i f i e d , g i v e n that t h e r e are o t h e r i n c o m p a t i b l e b e l i e f s that a r e e q u a l l y c o h e r e n t . F o r t h e r e w o u l d t h e n b e n o j u s t i f i c a t i o n for b e i n g a C h r i s t i a n rather than a Hindu. E v e n if c o h e r e n c e is c o n s t r u e d in s u c h a w a y that a b o d y of beliefs m u s t b e m o r e c o h e r e n t t h a n a n y i n c o m p a t i b l e s e t of b e l i e f s in o r d e r to c o u n t a s j u s t i f i e d , t h e r e will still b e p r o b l e m s . F o r s u p p o s e that I h a d r e a d J a n e A u s t e n ' s Emma a s a c h i l d , u n d e r t h e m i s t a k e n i m p r e s s i o n that it w a s t h e b i o g r a p h y of a historical i n d i v i d u a l . T h e n as a n a d u l t I still retain a g r e a t m a n y beliefs about E m m a W o o d h o u s e , but have forgotten h o w I came to h a v e t h e m . S i n c e t h e s e b e l i e f s c o n s t i t u t e a c o n s i s t e n t , m u t u a l l y s u p p o r t i n g s e t , a c o h e r e n t i s t s e e m s c o m m i t t e d to s a y i n g that t h e y a r e j u s t i f i e d . B u t this is c o u n t e r - i n t u i t i v e . I t h i n k w e s h o u l d b e s t r o n g l y i n c l i n e d to d e n y that a c o h e r e n t s e t of fictional beliefs c o u l d c o u n t as j u s t i f i e d in this e x a m p l e . C o h e r e n t i s t s a r e n o d o u b t c o r r e c t to s t r e s s , a s a g a i n s t s o m e (but n o t all) f o r m s of f o u n d a t i o n a l i s m , that a j u s t i f i c a t i o n for a belief c a n a p p e a l to n o n - s e l f - e v i d e n t p r i n c i p l e s , s u c h a s i n f e r e n c e to t h e b e s t overall e x p l a n a t i o n of a g i v e n r a n g e of p h e n o m e n a . But the beliefs within an explanatory n e t w o r k m u s t s u r e l y b e a n c h o r e d s o m e w h e r e . T h e y c a n n o t j u s t 'float

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f r e e ' of all c o n s t r a i n t , a s d o m y b e l i e f s a b o u t E m m a W o o d h o u s e in t h e e x a m p l e a b o v e . O n t h e c o n t r a r y , I s u g g e s t that t h e r e m u s t b e s o m e b e l i e f s g i v e n t o u s in e x p e r i e n c e , p r o v i d i n g t h e data that t h e c o h e r e n t n e t w o r k e x p l a i n s . J u s t s u c h a w e a k e n e d f o r m of c o h e r e n t i s m ( w h i c h m a y a l t e r n a t i v e l y b e s e e n as a w e a k e n e d f o r m of f o u n d a t i o n a l i s m ) will b e c o n s i d e r e d in m o r e detail in chapter 12. If s o m e suitably w e a k e n e d f o r m of c o h e r e n t i s m is c o r r e c t , t h e n it will c e r t a i n l y b e p o s s i b l e that t h e r e s h o u l d b e i n n a t e k n o w l e d g e . For s u p p o s e that s o m e set of true b e l i e f s w e r e i n n a t e , s e r v i n g to p r o v i d e a c o h e r e n t e x p l a n a t i o n of the data p r o v i d e d b y s u b s e q u e n t e x p e r i e n c e . T h e n p r o v i d e d that t h o s e b e l i e f s c o u l d n o t h a v e b e e n (or at least w e r e n o t ) learned from t h e e x p e r i e n c e s in q u e s t i o n , t h e y w o u l d c o u n t a s i n n a t e l y k n o w n . T h e y w o u l d b e t r u e b e l i e f s w h o s e justification is t r i g g e r e d by e x p e r i e n c e (either g e n e r a l l y or locally), r a t h e r t h a n d e r i v e d from it. T h i s s u g g e s t i o n c a n n o t , h o w e v e r , s e r v e to explain w h y L o c k e ( a n d o t h e r e m p i r i c i s t s ) failed to d e p l o y t h e a r g u m e n t a g a i n s t t h e possibility of i n n a t e k n o w l e d g e s k e t c h e d earlier. F o r it s e e m s c e r t a i n that n o n e of t h e classical p r o t a g o n i s t s in this d e b a t e — w h e t h e r e m p i r i c i s t or r a t i o n a l i s t — e n d o r s e d a c o h e r e n t i s t c o n c e p t i o n of j u s t i f i c a t i o n . A b e t t e r e x p l a n a t i o n is that L o c k e e m p l o y e d s o m e o t h e r a c c o u n t of k n o w l e d g e , w h i c h w o u l d l e a v e o p e n t h e possibility o f i n n a t e k n o w l e d g e e v e n w h e n c o n j o i n e d w i t h f o u n d a t i o n a l i s m . T h i s idea is a l s o s u p p o r t e d by c o n s i d e r a t i o n s o f c h a r i t y , s i n c e t h e r e a r e p o w e r f u l r e a s o n s for t h i n k i n g that t h e j u s t i f i c a t i o n a l i s t c o n c e p t i o n of k n o w l e d g e is i n c o r r e c t . To this issue I n o w turn.

Against Justificationalism W h i l e a c o n c e p t i o n of k n o w l e d g e a s j u s t i f i e d t r u e b e l i e f m a y raise a difficulty for t h e possibility of i n n a t e k n o w l e d g e , that c o n c e p t i o n h a s itself c o m e u n d e r i n c r e a s i n g p r e s s u r e in r e c e n t d e c a d e s . O n e p r o b l e m w i t h it is t h a t w e a r e t h e n c o n s t r a i n e d to d e n y k n o w l e d g e to t h o s e , s u c h a s c h i l d r e n , w h o m a y b e u n a w a r e of t h e j u s t i f i c a t i o n for t h e i r t r u e b e l i e f s . Y e t it is c o u n t e r - i n t u i t i v e to i n s i s t that a c h i l d d o e s n o t k n o w that F a t h e r

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is w a s h i n g u p d i s h e s ( e v e n t h o u g h t h e c h i l d c a n s e e t h a t h e is d o i n g s o ) , o n t h e g r o u n d s that t h e child is as y e t i n c a p a b l e of p r o v i d i n g a n y sort of j u s t i f i c a t i o n for its belief. (After all, t h e child m a y b e j u s t a s reliable in r e p o r t i n g s u c h m a t t e r s a s t h e rest of u s . ) E q u a l l y , s u p p o s e t h a t y o u a r e u n a b l e to r e s p o n d a d e q u a t e l y to a s c e p t i c w h o d e m a n d s to k n o w w h a t r e a s o n y o u h a v e for b e l i e v i n g t h a t y o u a r e n o t n o w d r e a m i n g . T h e n if j u s t i f i c a t i o n a l i s m is c o r r e c t , y o u d o n o t in fact k n o w t h a t y o u a r e a w a k e . It will o n l y b e t h e p r i v i l e g e d f e w , w h o c a n a n s w e r t h e s c e p t i c , w h o m a y b e said to k n o w t h a t t h e y a r e n o t d r e a m i n g ; t h e rest of h u m a n k i n d , in l a c k i n g a j u s t i f i c a t i o n , will l a c k knowledge also. 1

T h i s p r o b l e m is really v e r y w i d e s p r e a d . F o r f e w of u s a r e c a p a b l e of articulating a n y t h i n g like a c o n v i n c i n g j u s t i f i c a t i o n for m o r e t h a n a h a n d f u l of o u r b e l i e f s . (Try a s k i n g a n o r d i n a r y p e r s o n for their r e a s o n s for o n e of their e v e r y d a y b e l i e f s — f o r e x a m p l e , their b e l i e f as to t h e d a t e of their m o t h e r ' s b i r t h d a y — a n d s e e h o w q u i c k l y their f e e b l e a t t e m p t s at j u s t i f i c a t i o n will r u n o u t . ) Y e t w e c a n n o t a v o i d t h e difficulty b y s a y i n g that k n o w l e d g e o n l y r e q u i r e s t h a t t h e r e be a j u s t i f i c a t i o n , n o t t h a t t h e s u b j e c t b e a w a r e o f it. F o r , a s w e s a w earlier, this w o u l d t h e n p e r m i t m a n y b e l i e f s that a r e really j u s t g u e s s e s to c o u n t a s k n o w l e d g e . N e i t h e r will it h e l p to s a y that k n o w l e d g e o n l y r e q u i r e s that a j u s t i f i c a t i o n b e constructable f r o m a m o n g s t t h e s u b j e c t ' s o t h e r b e l i e f s , n o t that t h e s u b j e c t n e e d a c t u a l l y , t h e m s e l v e s , h a v e e f f e c t e d s u c h a c o n s t r u c t i o n . F o r s u p p o s e that I h a d laid a b e t o n t h e w i n n i n g h o r s e b e c a u s e I l i k e d t h e c o l o u r s in w h i c h h e r jockey w a s dressed. This w o u l d surely b e a m e r e g u e s s r a t h e r t h a n k n o w l e d g e , e v e n if I did in fact k n o w (but failed t o recall) t h a t s h e h a d w o n all of h e r last t e n r a c e s . N o t o n l y d o e s j u s t i f i c a t i o n a l i s m conflict w i t h o u r c o m m o n sense views about the circumstances in which people may be said to p o s s e s s k n o w l e d g e , b u t it is far f r o m clear w h y w e s h o u l d want to insist that k n o w l e d g e r e q u i r e s j u s t i f i c a t i o n . F o r o u r m a i n i n t e r e s t in t h e q u e s t i o n w h e t h e r or n o t s o m e o n e k n o w s s o m e t h i n g is t h a t a p o s i t i v e a n s w e r will w a r r a n t u s in a d o p t i n g that b e l i e f for o u r s e l v e s . A n d w h i l e t h e fact t h a t t h e y a r e j u s t i f i e d in h o l d i n g their b e l i e f m a y b e s u f f i c i e n t to g i v e u s s u c h a w a r r a n t , it is u n c l e a r w h y it s h o u l d b e n e c e s s a r y . 1

I h e r e a s s u m e t h a t t h e r e is a n a n s w e r t o t h e s c e p t i c . S e e c h a p t e r s 11 a n d 1 2 .

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T h e m a i n u s e w e h a v e for t h e c o n c e p t of k n o w l e d g e is that if s o m e o n e k n o w s s o m e t h i n g , t h e n w e m a y safely a d d w h a t t h e y k n o w to o u r o w n s t o c k of b e l i e f s . W e t h e r e f o r e n e e d to b e able to e s t a b l i s h that t h e y h a v e k n o w l e d g e i n d e p e n d e n t l y of a s s e s s i n g , for o u r s e l v e s , t h e truth of their belief. (If w e c o u l d d o that, w e s h o u l d n o t need to k n o w that t h e y k n o w . ) A n d t h e basic fact w e n e e d to e s t a b l i s h is s i m p l y that their belief is, in t h e c i r c u m s t a n c e s , likely to b e true. W h e t h e r or n o t t h e y t h e m s e l v e s c a n p r o v i d e r e a s o n s for their belief is of n o particular i m p o r t a n c e . All that really m a t t e r s is that t h e b e l i e v e r s h o u l d , in t h e c i r c u m s t a n c e s , b e reliable (or reliable e n o u g h ) on t h e topic in h a n d . I n d e e d , it s e e m s to m e that from the p o i n t of v i e w of o u r practical i n t e r e s t in k n o w l e d g e , t h e a p p r o p r i a t e c o n c e p t is a reliabilist o n e , of t h e sort to b e d e f e n d e d in t h e n e x t s e c t i o n . 2

E v e n if j u s t i f i e d true belief is n o t n e c e s s a r y for k n o w l e d g e , it m a y still b e s u f f i c i e n t . B u t this t h e s i s , t o o , is v u l n e r a b l e to c o u n t e r - e x a m p l e . T h u s s u p p o s e that I h a d t u r n e d o n m y radio in o r d e r to h e a r a live a c c o u n t of t h e 1988 O l y m p i c 1 0 0 - m e t r e final, h a v i n g j u s t r e a d in t h e p a p e r that s u c h a p r o g r a m m e w a s d u e to b e b r o a d c a s t at that t i m e . I d u l y h e a r t h e c o m m e n t a t o r d e s c r i b e a r a c e in w h i c h B e n J o h n s o n b e a t s Carl L e w i s , s e t t i n g a w o r l d r e c o r d in t h e p r o c e s s — w h i c h is exactly w h a t w a s in fact h a p p e n i n g . B u t u n k n o w n to m e t h e r e w a s a fault in t h e satellite t r a n s m i s s i o n f r o m S e o u l , a n d t h e y w e r e in fact b r o a d c a s t i n g a repeat commentary from the previous year's World Champions h i p s i n s t e a d , in w h i c h a similar r a c e t o o k p l a c e . H e r e 1 h a v e a j u s t i f i e d t r u e belief that J o h n s o n h a s j u s t set a w o r l d record in b e a t i n g L e w i s , b u t I surely d o n o t k n o w it. T h e r e a r e m a n y e x a m p l e s of this g e n e r a l s o r t . 3

W h a t t h i s e x a m p l e s h o w s is at least that t h e a c c o u n t of k n o w l e d g e as j u s t i f i e d true belief n e e d s to b e s u p p l e m e n t e d in s o m e w a y . P e r h a p s w e m i g h t r e q u i r e in a d d i t i o n that t h e belief s h o u l d b e n o n - a c c i d e n t a l l y c o n n e c t e d w i t h t h e fact that it c o n c e r n s . F o r t h e distinctive f e a t u r e of t h e e x a m p l e is that t h e W h i l e I o t h e r w i s e c o n c u r w i t h E d w a r d C r a i g in ' T h e P r a c t i c a l E x p l i c a t i o n o f K n o w l e d g e ' , Proceedings of the Aristotelian Society, 1 9 8 7 , h e s e e m s t o m e t o g o w r o n g o n j u s t this p o i n t . F o r a d e f e n c e o f t h e g e n e r a l a p p r o a c h t o c o n c e p t u a l i s s u e s e x e m p l i f i e d b o t h h e r e a n d in C r a i g ' s p a p e r , s e e m y ' C o n c e p t u a l P r a g m a t i s m ' , Synthese, 1 9 8 7 . 2

T h e y a r e g e n e r a l l y k n o w n a s ' G e t t i e r e x a m p l e s ' a f t e r E . G e t t i e r a u t h o r of 'Is J u s t i f i e d T r u e Belief K n o w l e d g e ? ' , Analysis, 1 9 6 3 . 3

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t r u t h o f t h e b e l i e f i n q u e s t i o n is e n t i r e l y f o r t u i t o u s , d e s p i t e b e i n g j u s t i f i e d . B u t o u r earlier a r g u m e n t s ( c o n c e r n i n g t h e k n o w l e d g e of c h i l d r e n , a n d your k n o w l e d g e that you are n o w awake) s u g g e s t s o m e t h i n g m u c h m o r e r a d i c a l . F o r if a b e l i e f c a n c o u n t a s k n o w l e d g e a l t h o u g h t h e b e l i e v e r l a c k s a n y j u s t i f i c a t i o n for it, t h e n w e s h o u l d reject the justification-condition altogether, r e p l a c i n g it w i t h s o m e o t h e r c o n d i t i o n .

C a u s a l Theories a n d Reliabilism S o m e h a v e d e v e l o p e d a n a c c o u n t of k n o w l e d g e t h a t is c a u s a l in c h a r a c t e r . T h e y h a v e said t h a t k n o w l e d g e is t r u e b e l i e f that is c a u s e d b y t h e fact w h i c h it c o n c e r n s . T h i s c a n e x p l a i n w h y , in the e x a m p l e above, my belief that J o h n s o n has b r o k e n the world r e c o r d d o e s n o t c o u n t a s a c a s e of k n o w l e d g e . F o r t h e fact of his h a v i n g b r o k e n t h e r e c o r d fails to p l a y a n y role in t h e c a u s a t i o n of m y b e l i e f . T h e a c c o u n t c a n a l s o e x p l a i n w h y t h e c h i l d k n o w s t h a t its f a t h e r is w a s h i n g u p , d e s p i t e l a c k i n g a j u s t i f i c a t i o n . F o r t h e c h i l d ' s b e l i e f is in fact c a u s e d b y p e r c e i v i n g F a t h e r at w o r k at t h e s i n k . S i m i l a r l y , y o u m a y b e s a i d to k n o w t h a t y o u a r e n o t n o w d r e a m i n g , d e s p i t e y o u r inability to a n s w e r t h e s c e p t i c , p r o v i d e d t h a t y o u r b e l i e f t h a t y o u a r e n o t d r e a m i n g is in fact c a u s e d b y t h e fact that y o u a r e a w a k e . 4

A l t h o u g h t h e c a u s a l t h e o r y of k n o w l e d g e is in m a n y w a y s a t t r a c t i v e , it r u n s i n t o t r o u b l e if it is to a l l o w for t h e possibility of k n o w l e d g e o f t h e f u t u r e , a n d o f k n o w l e d g e of u n r e s t r i c t e d l y g e n e r a l s t a t e m e n t s . F o r f u t u r e s t a t e s o f affairs s u r e l y c a n n o t b e c a u s e s o f p r e s e n t belief, a n d it is i m p l a u s i b l e to s u g g e s t that o u r b e l i e f s a b o u t g e n e r a l l a w s o f n a t u r e a r e in fact c a u s e d b y t h o s e l a w s t h e m s e l v e s . T h u s s u p p o s e t h a t I h a v e j u s t s e t light to t h e f u s e o n a f i r e w o r k . I k n o w t h a t it is a r o c k e t of reliable m a n u f a c t u r e , w h i c h h a s n e v e r f a i l e d i n t h e p a s t . I k n o w that it h a s b e e n s t o r e d in d r y c o n d i t i o n s , t h a t t h e w e a t h e r itself is n o w d r y , a n d t h a t t h e r e is n o w i n d . S u r e l y in t h e s e c o n d i t i o n s I m a y k n o w t h a t t h e r o c k e t will s h o r t l y t a k e off. B u t it is n o t t h e fact t h a t t h e r o c k e t will t a k e off t h a t c a u s e s m y b e l i e f t h a t it will (as 4

T h i s is r o u g h l y t h e p o s i t i o n h e l d b y R o b e r t N o z i c k , Philosophical

(Oxford: O x f o r d University Press, 1981), ch. 3.

Explanations

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73

t h e c a u s a l t h e o r y of k n o w l e d g e w o u l d r e q u i r e ) . T h i s w o u l d i n v o l v e b a c k w a r d s c a u s a t i o n , w h i c h is i m p o s s i b l e . M y b e l i e f is r a t h e r c a u s e d b y t h e facts that I h a v e m e n t i o n e d , s u c h as m y belief that t h e f i r e w o r k is d r y . E q u a l l y , c o n s i d e r m y belief that all m a s s i v e b o d i e s attract o n e a n o t h e r ( t h e l a w of g r a v i t y ) . T h i s m a y s u r e l y c o u n t as k n o w l e d g e . B u t m y b e l i e f is n o t c a u s e d b y t h e fact that all b o d i e s attract (past, f u t u r e , a n d d i s t a n t ) , b u t r a t h e r b y t h e b o d i e s that I h a v e o b s e r v e d , a n d b y t h e r e p o r t s of o t h e r o b s e r v e r s a n d s c i e n t i s t s . S o a g a i n , w e a p p e a r to h a v e a c a s e of k n o w l e d g e w i t h o u t c a u s a t i o n by t h e fact w h i c h it concerns. W e c a n k e e p all t h e a d v a n t a g e s of t h e c a u s a l t h e o r y , w h i l e a v o i d i n g its difficulties, if w e s a y that k n o w l e d g e is true belief t h a t is caused by a reliable process. A reliable p r o c e s s is o n e that g e n e r a l l y i s s u e s in true b e l i e f s , a n d that also s e r v e s , in t h e p a r t i c u l a r c a s e in h a n d , to d i s c r i m i n a t e reliably truth f r o m relevant falsehood. 5

T h i s c a n e x p l a i n h o w w e m a y h a v e k n o w l e d g e of t h e f u t u r e , if t h e p r o c e s s of i n f e r e n c e f r o m p a s t facts a n d p r e s e n t t e n d e n c i e s is (in t h e c i r c u m s t a n c e s ) a reliable o n e . It c a n also a c c o u n t for o u r k n o w l e d g e of l a w s of n a t u r e , if t h e p r o c e s s e s of i n d u c t i o n a n d i n f e r e n c e to t h e b e s t e x p l a n a t i o n e m p l o y e d b y s c i e n t i s t s a r e also g e n e r a l l y reliable. Y e t w e c a n still e x p l a i n w h y I w o u l d lack k n o w l e d g e of J o h n s o n ' s v i c t o r y , in t h e e x a m p l e d i s c u s s e d a b o v e . F o r w h i l e l i s t e n i n g to r a d i o b r o a d c a s t s m a y b e a g e n e r a l l y reliable m e t h o d of a c q u i r i n g true b e l i e f s , in this c a s e m y b e l i e f w o u l d h a v e b e e n t h e s a m e e v e n if J o h n s o n h a d not w o n . In t h e c i r c u m s t a n c e s t h e p r o c e s s that c a u s e s m y belief is n o t reliable in d i s c r i m i n a t i n g t r u t h f r o m r e l e v a n t f a l s e h o o d . W e c a n also still e x p l a i n t h e fact that t h e child k n o w s its f a t h e r is w a s h i n g u p , a s w e l l as y o u r k n o w l e d g e that y o u a r e n o t n o w d r e a m i n g . F o r t h e c h i l d ' s p e r c e p t i o n s in c i r c u m s t a n c e s s u c h as t h e s e (with t h e o b s e r v e d e v e n t s t a k i n g p l a c e n o t t o o far a w a y , in g o o d l i g h t i n g , a n d n o t t o o swiftly) will g e n e r a l l y r e s u l t in t r u e b e l i e f s . A n d your belief that you are n o w a w a k e results from a process that i n v o l v e s y o u r c u r r e n t c o n s c i o u s a w a r e n e s s , w h i c h is a l s o reliable. F o r a detailed exposition a n d d e f e n c e of reliabilism, see Alvin G o l d m a n , Epistemology and Cognition ( C a m b r i d g e , M a s s . : H a r v a r d U n i v e r s i t y P r e s s , 1 9 8 6 ) , c h . 3. 5

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W h i l e t h e t h e s i s that k n o w l e d g e i m p l i e s c a u s a t i o n b y a reliable p r o c e s s is b e g i n n i n g to l o o k p l a u s i b l e , it m i g h t b e c l a i m e d t h a t w e h a v e b e e n t o o h a s t y i n d r o p p i n g t h e justification-condition. For consider the following e x a m p l e . 1 am taking p a r t in a p s y c h o l o g i c a l e x p e r i m e n t , w h e r e t h e e x p e r i m e n t e r h a s told m e that I h a v e b e e n g i v e n a d r u g t h a t will totally distort m y visual perception. N e v e r t h e l e s s , I perversely c o n t i n u e to believe, o n t h e b a s i s of m y p e r c e p t i o n s , t h a t t h e r e is a p i n k rabbit sitting o n t h e d e s k in f r o n t of m e . B u t in fact t h e e x p e r i m e n t e r h a s g i v e n m e a p l a c e b o , a n d t h e r e really is a p i n k rabbit o n the d e s k , which has escaped from the genetics laboratory next door. This is a c a s e in w h i c h m y b e l i e f a p p e a r s to b e c a u s e d by a reliable p r o c e s s ( u n d i s t o r t e d p e r c e p t i o n ) , a n d is in fact t r u e . B u t , it m a y b e u r g e d , I surely d o n o t know t h a t t h e r e is a rabbit o n t h e d e s k . T h i s is b e c a u s e it i s , in t h e c i r c u m s t a n c e s , u n r e a s o n a b l e of m e t o trust m y visual p e r c e p t i o n s . 6

In fact, h o w e v e r , t h e c o r r e c t r e s p o n s e to this e x a m p l e is that I do h a v e k n o w l e d g e that t h e r e is a p i n k rabbit on t h e d e s k b e f o r e m e . T h i s is b e c a u s e I a m , in t h e c i r c u m s t a n c e s , a reliable i n f o r m a n t o n s u c h m a t t e r s . T h e i n t u i t i o n that I d o n o t h a v e k n o w l e d g e o n l y a r i s e s t h r o u g h a c o n f u s i o n of l e v e l s . It is true t h a t , r e p r e s e n t i n g t h e e x a m p l e to m y s e l f in t h e first p e r s o n s i n g u l a r , I c a n n o t c o r r e c t l y claim to h a v e k n o w l e d g e of t h e p r e s e n c e of t h e rabbit. B u t o t h e r s m a y c o r r e c t l y c l a i m this of m e , a n d I m a y correctly c l a i m it o f m y s e l f at a later t i m e w h e n t h e details of t h e s i t u a t i o n e m e r g e . T h i s will b e m a d e clear in t h e next section.

O r d e r s of K n o w l e d g e R e l i a b i l i s m c a n o n l y b e a c c e p t a b l e if w e a r e p r e p a r e d to d e n y w h a t is s o m e t i m e s called ' t h e K K t h e s i s ' , w h i c h h o l d s t h a t in o r d e r to k n o w s o m e t h i n g , y o u m u s t at t h e s a m e t i m e k n o w that y o u k n o w it. F o r t h e p r o c e s s t h a t g i v e s rise to a belief c a n i n fact T h e e x a m p l e is a d e v e l o p m e n t o f G o l d m a n ' s in Epistemology and Cognition, 5 3 . H e u s e s it t o a r g u e f o r t h e i n c l u s i o n of a j u s t i f i c a t i o n - c o n d i t i o n in t h e a c c o u n t o f k n o w l e d g e , w h i c h h e t h e n t r i e s t o c a s h o u t in a reliabilist w a y . I shall a r g u e i n t h e n e x t s e c t i o n t h a t h e is w r o n g o n b o t h c o u n t s . I o n c e d e p l o y e d a s i m i l a r e x a m p l e m y s e l f in d e f e n c e o f j u s t i f i c a t i o n a l i s m . S e e m y Introducing Persons ( L o n d o n : R o u t l e d g e , 1 9 8 6 ) , 6. i. A . 6

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b e reliable e v e n t h o u g h y o u y o u r s e l f d o n o t k n o w t h a t it is; i n d e e d , y o u m a y n o t e v e n k n o w w h a t t h a t p r o c e s s is. T h e n a c c o r d i n g t o reliabilism y o u r belief will c o u n t as k n o w l e d g e , b u t y o u will n o t k n o w that it is k n o w l e d g e . T h e r e is s o m e r e a s o n t o t h i n k that it is t h e K K t h e s i s that g i v e s rise t o j u s t i f i c a t i o n a l i s m . F o r if k n o w i n g s o m e t h i n g r e q u i r e s that y o u k n o w t h a t y o u k n o w it, t h e n y o u will o n l y h a v e k n o w l e d g e if y o u k n o w that y o u r b e l i e f s h a v e b e e n f o r m e d in a w a y that r e n d e r s t h e m likely to b e t r u e — in o t h e r w o r d s , if y o u p o s s e s s a j u s t i f i c a t i o n for t h e belief. B u t w h y s h o u l d t h e K K t h e s i s b e a c c e p t e d ? S u r e l y k n o w i n g (first-order k n o w l e d g e ) is o n e t h i n g , k n o w i n g that y o u k n o w ( s e c o n d - o r d e r k n o w l e d g e ) is a n o t h e r . I n d e e d , the t h e s i s t h r e a t e n s to d e g e n e r a t e i n t o a r e g r e s s . For if t a k e n g e n e r a l l y , t h e n y o u will o n l y k n o w t h a t you k n o w s o m e t h i n g , in t u r n , if y o u k n o w that you k n o w that you k n o w it; a n d s o o n . It s e e m s to m e likely that b o t h j u s t i f i c a t i o n a l i s m a n d t h e K K t h e s i s result f r o m c o n f l a t i n g o u r b a s i c i n t e r e s t a s e p i s t e m o l o g i s t s ( t h e o r i s t s of k n o w l e d g e ) with w h a t it is that w e t a k e an i n t e r e s t in, n a m e l y k n o w l e d g e . I p r o p o s e to a r g u e for this in a n u m b e r o f s t e p s . First, I claim that t h e c e n t r a l q u e s t i o n of e p i s t e m o l o g y is w h a t w e m a y k n o w ourselves to k n o w (a s e c o n d - o r d e r question). T h i s is easily o v e r l o o k e d . F o r if I ask m y s e l f ' W h a t d o I k n o w ? ' , t h e t e r m ' k n o w ' o n l y figures in t h e q u e s t i o n o n c e . But in fact, in r e t u r n i n g a positive a n s w e r to t h e q u e s t i o n w h e t h e r I k n o w that s u c h - a n d - s u c h , I s h o u l d b e tacitly c l a i m i n g to k n o w t h a t I k n o w it. F o r s u p p o s e that I a s s e r t ' T h e o z o n e l a y e r is s h r i n k i n g ' . T h i s is in fact a claim to know that t h e o z o n e l a y e r is s h r i n k i n g . A n y u n c o n d i t i o n a l a s s e r t i o n is, in effect, a tacit k n o w l e d g e - c l a i m . F o r to r e s p o n d to it b y s a y i n g ' B u t y o u d o n ' t really knoiv t h a t ' is to c h a l l e n g e t h e s p e a k e r ' s r i g h t to say w h a t t h e y h a v e s a i d . S i m i l a r l y , t h e n , if I a s s e r t 'I k n o w that t h e o z o n e layer is s h r i n k i n g ' . T h i s is i n fact a tacit c l a i m to k n o w that I k n o w it. M y s e c o n d t h e s i s is t h a t t h e o n l y g e n e r a l l y reliable m e t h o d of a c q u i r i n g s e c o n d - o r d e r b e l i e f s a b o u t w h a t I k n o w (that i s , of a c q u i r i n g s e c o n d - o r d e r k n o w l e d g e ) is b y a p r o c e s s of r e a s o n i n g . T h e o n l y w a y to k n o w t h a t y o u k n o w , is to c o n s t r u c t a j u s t i f i c a t i o n for c l a i m i n g to h a v e k n o w l e d g e . T h e r e c o u l d n o t , for e x a m p l e , b e a n y p r o c e s s of i n t r o s p e c t i o n t h a t w o u l d b e reliable i n o b t a i n i n g for u s b e l i e f s a b o u t o u r o w n s t a t e s o f

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k n o w l e d g e . F o r w h i l e i n t r o s p e c t i o n m i g h t h a v e a c c e s s to m y first-order s t a t e s of belief, it c a n n o t h a v e a c c e s s to t h e fact that t h o s e b e l i e f s w e r e p r o d u c e d b y a reliable p r o c e s s , w h e n t h e y w e r e . It f o l l o w s that w h e n w e c o m e to d o e p i s t e m o l o g y ( s e e k i n g to k n o w w h a t w e k n o w ) , j u s t i f i c a t i o n a l i s m a n d reliabilism c o n v e r g e : e a c h will arrive, b y d i f f e r e n t r o u t e s , at t h e v i e w that w e n e e d to s e e k j u s t i f i c a t i o n for o u r c l a i m s to k n o w l e d g e . It w o u l d t h e n be quite natural that p h i l o s o p h e r s s h o u l d mistakenly slip i n t o t h i n k i n g t h a t k n o w l e d g e itself ( w h e t h e r first-order or second-order) requires justification. 7

T h i s , t h e n , is h o w w e s h o u l d r e s p o n d to t h e e x a m p l e of the p i n k rabbit p r e s e n t e d earlier: s i n c e m y belief in t h e p r e s e n c e of a rabbit is in fact p r o d u c e d by a reliable p r o c e s s , I m a y truly b e said (by o t h e r s o r b y m y s e l f at a later t i m e ) to h a v e k n o w l e d g e . F o r s o m e o n e w h o k n o w s that I h a v e b e e n g i v e n a p l a c e b o ( a n d s o w h o k n o w s that m y p e r c e p t i o n will m o s t likely b e a c c u r a t e ) m a y r e a s o n a b l y treat m e as a reliable i n f o r m a n t on t h e m a t t e r . It is o n l y w h e n I raise t h e q u e s t i o n a b o u t m y s e l f at t h e t i m e — ' D o I k n o w that t h e r e is a p i n k rabbit h e r e ? ' — t h a t t h e a n s w e r h a s to b e n e g a t i v e . F o r t h e q u e s t i o n i s , tacitly, a s e c o n d - o r d e r o n e . A n affirmative a n s w e r will c l a i m to k n o w that I k n o w . B u t , a s w e h a v e j u s t s e e n , s u c h s e c o n d - o r d e r c l a i m s h a v e to b e b a s e d o n a p r o c e s s of r e a s o n i n g . A n d it is plain t h a t , in t h e c i r c u m s t a n c e s , I lack a n y j u s t i f i c a t i o n for s a y i n g that I k n o w . It is i m p o r t a n t t o n o t e that t h e r e l e v a n t c o n c e p t of justification, in this c o n t e x t , h a s to d o w i t h t h e r e a s o n s that a r e available to t h e p e r s o n w h o s e k n o w l e d g e is in q u e s t i o n . W h e t h e r or n o t a b e l i e f is j u s t i f i e d h a s to b e d e t e r m i n a b l e f r o m t h e p e r s p e c t i v e of t h e s u b j e c t s t h e m s e l v e s . T h i s is b e c a u s e t h e m a i n u s e w e h a v e for t h e c o n c e p t of j u s t i f i c a t i o n is in d e t e r m i n i n g w h a t w e o u r s e l v e s s h o u l d b e l i e v e . T h e q u e s t i o n w h e t h e r s o m e o n e else is j u s t i f i e d in h o l d i n g a b e l i e f is g e n e r a l l y of v e r y little i n t e r e s t , e x c e p t in s o far as b e l i e v i n g o n t h e b a s i s of a j u s t i f i c a t i o n is o n e f o r m of reliable b e l i e f a c q u i s i t i o n , or e x c e p t b y w a y of p r o v i d i n g a moral applicable to our o w n case. W e therefore want a concept w h o s e c o n d i t i o n s of a p p l i c a t i o n a r e d e f i n e d in s u c h a w a y a s to 8

T h i s p o i n t will p r o v e t o b e o f s o m e i m p o r t a n c e in c h a p t e r s 11 a n d 1 2 , w h e n w e c o m e to consider the p r o b l e m of scepticism. 7

T h i s is w h e r e G o l d m a n ' s v e r s i o n o f r e l i a b i l i s m s e e m s t o m e to g o b a d l y w r o n g , i n m a k i n g j u s t i f i c a t i o n a m a t t e r o f o b j e c t i v e reliability. 8

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b e available to u s . ( T h i s is in c o n t r a s t w i t h t h e c a s e of k n o w l e d g e itself, w h e r e o u r m a i n u s e for t h e c o n c e p t is a t h i r d - p e r s o n o n e — o n t h e q u e s t i o n a s t o w h e t h e r s o m e o n e k n o w s s o m e t h i n g will t u r n w h e t h e r or n o t I m y s e l f s h o u l d b e l i e v e that t h i n g . H e r e all that m a t t e r s is that t h e p e r s o n in q u e s t i o n s h o u l d b e reliable o n t h e i s s u e at h a n d . ) In t h e light of t h e a b o v e c o n s i d e r a t i o n s it s e e m s to m e q u i t e p o s s i b l e that classical p h i l o s o p h e r s s u c h a s L o c k e a n d D e s c a r t e s m a y h a v e b e e n implicitly w o r k i n g with a reliabilist c o n c e p t i o n of k n o w l e d g e , d e s p i t e their o v e r t c o n c e r n with j u s t i f i c a t i o n . F o r as e p i s t e m o l o g i s t s t h e y w e r e i n t e r e s t e d in t h e q u e s t i o n of w h a t w e c o u l d k n o w o u r s e l v e s to k n o w . T o s e e k an a n s w e r to this q u e s t i o n is to l o o k for r e a s o n s in s u p p o r t of o u r v a r i o u s (firsto r d e r ) c l a i m s to k n o w l e d g e . But t h e fact that t h e p r o c e s s of a c q u i r i n g s e c o n d - o r d e r k n o w l e d g e of this sort i n v o l v e s justification is quite c o n s i s t e n t w i t h t h e t h e s i s that k n o w l e d g e itself is reliably a c q u i r e d true belief. I n d e e d , D e s c a r t e s ' s s t r a t e g y in t h e Meditations, for e x a m p l e , is q u i t e n a t u r a l l y i n t e r p r e t e d in this light. F o r w h a t h e w i s h e s to k n o w is w h e t h e r t h e p r o c e s s e s t h r o u g h w h i c h h e a c q u i r e d his b e l i e f s w e r e reliable. H e b e l i e v e s that h e c a n a n s w e r this q u e s t i o n a f f i r m a t i v e l y , b y virtue of p r o v i n g t h e e x i s t e n c e of a v e r a c i o u s G o d . But t h e r e is n o s u g g e s t i o n that o r d i n a r y p e o p l e d o n o t h a v e p e r c e p t u a l k n o w l e d g e until t h e y , t o o , h a v e g r a s p e d s u c h a p r o o f (that is, until t h e y , t o o , h a v e p r o v i d e d a justification for their k n o w l e d g e - c l a i m s ) . R a t h e r , t h e y h a v e k n o w l e d g e b e c a u s e p e r c e p t i o n is in fact reliable. W h a t t h e y lack is o n l y t h e k n o w l e d g e that t h e y k n o w .

Innateness and the A Priori If reliabilism is a c c e p t a b l e as a n a c c o u n t of k n o w l e d g e , t h e n t h e possibility of i n n a t e k n o w l e d g e is left o p e n . I n n a t e b e l i e f s will c o u n t as k n o w n p r o v i d e d that t h e p r o c e s s t h r o u g h w h i c h t h e y c o m e to b e i n n a t e is a reliable o n e ( p r o v i d e d , that i s , that t h e p r o c e s s t e n d s to g e n e r a t e b e l i e f s that a r e t r u e ) . T h e r e a r e t w o p o s s i b l e c a n d i d a t e s for s u c h a p r o c e s s : d i v i n e i n t e r v e n t i o n o n the one hand, and evolution on the other. W e could maintain, a s m o s t classical r a t i o n a l i s t s d i d , t h a t i n n a t e b e l i e f s a r e directly

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implanted in the m i n d by a veracious G o d . O r w e could hold that i n n a t e b e l i e f s h a v e b e e n a c q u i r e d t h r o u g h e v o l u t i o n , via n a t u r a l s e l e c t i o n . E a c h of t h e s e c a n d i d a t e p r o c e s s e s w o u l d m o s t p r o b a b l y b e reliable. W e shall r e t u r n to c o n s i d e r t h e m i n m o r e detail in later c h a p t e r s . I h a v e a r g u e d f o r a c o n c e p t i o n of k n o w l e d g e that w o u l d a l l o w innate k n o w l e d g e to be possible, no matter w h e t h e r w e have a f o u n d a t i o n a l i s t or a c o h e r e n t i s t c o n c e p t i o n of j u s t i f i c a t i o n . A n d I h a v e s u g g e s t e d that t h e r e a s o n w h y L o c k e did n o t e m p l o y t h e a r g u m e n t a g a i n s t i n n a t e k n o w l e d g e s k e t c h e d at t h e o u t s e t of this c h a p t e r is that h e t o o m a y h a v e c o n c e i v e d of k n o w l e d g e in reliabilist t e r m s . B u t w o u l d i n n a t e k n o w l e d g e , if it e x i s t e d , at t h e s a m e t i m e b e a priori? In o n e s e n s e at least it w o u l d b e . F o r , a s w e n o t e d in c h a p t e r 1, o n e t h i n g that c a n b e m e a n t b y s a y i n g that s o m e t h i n g is k n o w n a priori is that o u r k n o w l e d g e o f it is i n d e p e n d e n t of e m p i r i c a l s u p p o r t . In this s e n s e , a priori k n o w l e d g e is k n o w l e d g e that h a s n o t b e e n l e a r n e d f r o m e x p e r i e n c e . A n d i n n a t e k n o w l e d g e (reliably c a u s e d i n n a t e belief) would apparently possess just such a status, neither having been learned from experience, nor requiring support f r o m e x p e r i e n c e to qualify as k n o w l e d g e . H o w e v e r , to s a y t h a t i n n a t e k n o w l e d g e w o u l d b e a priori is o n e t h i n g , to s a y t h a t w e m a y k n o w t h a t w e k n o w it a priori is q u i t e a n o t h e r . K n o w l e d g e that is a priori in this s e n s e will n o t , u n l i k e w h a t is g e n e r a l l y h e l d c o n c e r n i n g t h e o t h e r m a i n traditional c a t e g o r y of t h e a priori, b e k n o w a b l e to b e s u c h b y a p r o c e s s of t h o u g h t a l o n e . O n t h e c o n t r a r y , to k n o w that a b e l i e f is b o t h i n n a t e a n d reliably p r o d u c e d , a n d h e n c e that a g i v e n i t e m of k n o w l e d g e is a priori, m a y r e q u i r e a r g u m e n t f r o m e m p i r i c a l p r e m i s s e s . A n a p p r o p r i a t e d e f e n c e o f n a t i v i s m will n o t itself b e a priori b u t b r o a d l y e m p i r i c a l . T h i s t o p i c — t h e d e f e n c e of n a t i v i s m — w i l l n o w o c c u p y u s o v e r t h e n e x t t h r e e chapters.

6 The Case for Innate Mental Structure c o n s i d e r e d the e m p i r i c i s t case against n a t i v i s m and f o u n d it w a n t i n g , I shall now begin to assess the evidence that supports nativism.

HAVING

Principles of Learning All e m p i r i c i s t s h a v e a l l o w e d that t h e m i n d is i n n a t e l y s t r u c t u r e d i n t o distinct f a c u l t i e s , i n c l u d i n g for e x a m p l e t h o u g h t , p e r c e p tion, a n d m e m o r y . A n d all h a v e a l l o w e d that t h e b a s i c m e c h a n i s m s i n v o l v e d in t h e a c q u i s i t i o n o f o u r b e l i e f s — s u c h a s the r e c o r d i n g o f e x p e r i e n c e s i n m e m o r y , a n d t h e l a w s of association amongst ideas—are innately given. ( O n e cannot, f r o m n o t h i n g , l e a r n h o w t o l e a r n . ) B u t t h e y h a v e d e n i e d that t h e m i n d d i v i d e s i n t o faculties w i t h i n n a t e c o n s t i t u e n t s t r u c t u r e s that a r e distinct f r o m o n e a n o t h e r , e m b o d y i n g i n f o r m a t i o n about the domains they concern. O n the contrary, they have i n s i s t e d that all b e l i e f - a c q u i s i t i o n p r i n c i p l e s a r e general o n e s , o p e r a t i n g i n similar w a y s f o r all d o m a i n s of k n o w l e d g e . M u c h o f t h e e v i d e n c e that h a s e m e r g e d o v e r r e c e n t d e c a d e s , o n t h e o t h e r h a n d , s u g g e s t s that t h e r e is i n n a t e i n f o r m a t i o n e m b o d i e d i n t h e l a n g u a g e faculty, for e x a m p l e , t h a t is n o t p r e s e n t in t h e faculty of v i s i o n o r vice v e r s a . (I shall h o l d o v e r until later, d i s c u s s i o n of the question whether such information m a y be described appropriately as 'knowledge'.) In fact t h e r e m i g h t a p p e a r t o b e t w o d i f f e r e n t i s s u e s h e r e . First, t h e r e is t h e q u e s t i o n w h e t h e r t h e v a r i o u s m e n t a l faculties e m p l o y distinct i n n a t e b e l i e f - a c q u i s i t i o n p r i n c i p l e s . S e c o n d l y , t h e r e is t h e q u e s t i o n w h e t h e r o u r i n n a t e m e c h a n i s m s o f belief a c q u i s i t i o n c a n b e said t o e m b o d y i n f o r m a t i o n a b o u t t h e w o r l d .

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It is e a s y e n o u g h to s e e w h y e m p i r i c i s t s s h o u l d h a v e d e n i e d t h e latter p o s s i b i l i t y . F o r e v e n if s u c h i n f o r m a t i o n c o u l d n o t itself b e c o u n t e d a s g e n u i n e k n o w l e d g e , it w o u l d plainly c o n t r i b u t e to o u r k n o w l e d g e , a n d m i g h t t h u s b e e x p e c t e d to fall w i t h i n t h e s c o p e of t h e e m p i r i c i s t r e j e c t i o n of n a t i v i s m . H o w e v e r , it is n o t n e a r l y s o o b v i o u s w h y e m p i r i c i s t s s h o u l d h a v e i n s i s t e d that all b e l i e f - a c q u i s i t i o n p r i n c i p l e s a r e g e n e r a l o n e s , t h e s a m e for all d o m a i n s of k n o w l e d g e . O n e p o s s i b l e e x p l a n a t i o n lies in t h e c o n c e p t i o n of s c i e n c e e n d o r s e d b y the early e m p i r i c i s t s . For t h e a s s u m p t i o n w i t h i n t h e p h y s i c a l s c i e n c e s at t h e t i m e w a s that all p h y s i c a l p h e n o m e n a s h o u l d b e e x p l i c a b l e in t e r m s of l a w s of n a t u r e that a r e entirely g e n e r a l , a p p l y i n g equally to all i n t e r a c t i o n s a n d c o m b i n a t i o n s of m a t t e r . In effect, it w a s a s s u m e d that all l a w s of n a t u r e that c o n c e r n t h e p h y s i c a l r e a l m s h o u l d b e r e d u c i b l e to t h e l a w s of p h y s i c s . N o w , as well as b e i n g e p i s t e m o l o g i s t s , t h e early e m p i r i c i s t s certainly s a w t h e m s e l v e s as a t t e m p t i n g to d e v e l o p a s c i e n c e of t h e m i n d ( m o r e o n this in c h a p t e r 9 ) . S o quite probably they would have imported the above assumption i n t o t h e d o m a i n of p s y c h o l o g y , t h u s i n s i s t i n g that all m e n t a l p r o c e s s e s s h o u l d b e e x p l i c a b l e i n t e r m s of the s a m e g e n e r a l p s y c h o l o g i c a l m e c h a n i s m s , s u c h as l a w s o f a s s o c i a t i o n a m o n g s t ideas. 1

F e w t h i n k e r s t o d a y w o u l d e n d o r s e the r e d u c t i o n i s m i n h e r e n t in early c o n c e p t i o n s of s c i e n c e . F e w w o u l d n o w i n s i s t that all s c i e n c e s t h a t deal w i t h p h y s i c a l p h e n o m e n a , i n c l u d i n g c h e m istry, b i o l o g y , a n d p h y s i o l o g y ( a n d s i n c e m o s t s c i e n t i s t s t o d a y are m a t e r i a l i s t s , t h e y w o u l d also a d d p s y c h o l o g y ) , m u s t in p r i n c i p l e b e r e d u c i b l e to p h y s i c s . O n t h e c o n t r a r y , m o s t w o u l d a l l o w that t h e special s c i e n c e s c a n c o n t a i n l a w s t h a t , w h i l e t h e y m a y ( i n d e e d m u s t ) b e consistent w i t h t h e l a w s of p h y s i c s , c a n n o t b e deduced from t h e m . T h e n if t h e l a w s of t h e special s c i e n c e s a r e a u t o n o m o u s , t h e r e is n o r e a s o n to i n s i s t , e i t h e r , that w i t h i n a n y g i v e n s c i e n c e , s u c h a s p s y c h o l o g y , all p h e n o m e n a m u s t b e e x p l i c a b l e i n t e r m s of a s i n g l e set of l a w s . W e t h e r e f o r e s e e m t o h a v e n o r e a s o n , t o d a y , for i n s i s t i n g that t h e p s y c h o l o g i c a l 2

O n this s e e A . D. S m i t h , ' O n P r i m a r y a n d S e c o n d a r y Q u a l i t i e s ' , Review, 1 9 9 0 . 1

2

S e e e . g . J e r r y F o d o r , Representations

Philosophical

(Brighton: Harvester, 1981), ch. 5.

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m e c h a n i s m s o p e r a t i v e in t h e v a r i o u s faculties of t h e m i n d should be the same throughout. B u t in fact t h e r e is also a m o r e direct e x p l a n a t i o n for t h e e m p i r i c i s t i n s i s t e n c e that l e a r n i n g m e c h a n i s m s s h o u l d b e t h e s a m e for all d o m a i n s of k n o w l e d g e . F o r if t h o s e m e c h a n i s m s w e r e t o differ in d i f f e r e n t c a s e s , t h i s could only m e a n that t h e y e m b o d i e d i n f o r m a t i o n a b o u t t h e d o m a i n s that t h e y c o n c e r n e d . S u p p o s e , for e x a m p l e , that t h e m e c h a n i s m s t h r o u g h w h i c h w e learn the g r a m m a r of o u r n a t i v e l a n g u a g e w e r e to differ f r o m t h e m e c h a n i s m s though which we acquire our c o m m o n - s e n s e b e l i e f s a b o u t material o b j e c t s . It is t h e n h a r d to s e e h o w this c o u l d b e s o — t o s e e w h y o n e could n o t , for e x a m p l e , e m p l o y t h e o n e set of l e a r n i n g p r i n c i p l e s to a c q u i r e k n o w l e d g e of t h e o t h e r d o m a i n — u n l e s s the m e c h a n i s m s in q u e s t i o n c o n t a i n e d , at least tacitly, i n f o r m a t i o n specific to t h e d o m a i n s that t h e y c o n c e r n e d . In w h i c h c a s e the i n s i s t e n c e on g e n e r a l l e a r n i n g p r i n c i p l e s m a y b e s e e n to derive from the e m p i r i c i s t v i e w that m e c h a n i s m s of l e a r n i n g s h o u l d n o t in a n y w a y e m b o d y i n f o r m a t i o n a b o u t t h e world. W e n o w n e e d to c o n s i d e r w h e t h e r e m p i r i c i s m is c o r r e c t in this r e g a r d . I shall f o c u s first o n the c a s e for a n i n n a t e l y s t r u c t u r e d l a n g u a g e faculty, c o n s i d e r i n g in t h e final section t h e c a s e for an i n n a t e l y s t r u c t u r e d visual faculty.

C h o m s k y on Language N o a m C h o m s k y h a s b e e n p r o m i n e n t in a r g u i n g that h u m a n b e i n g s p o s s e s s a distinct l a n g u a g e faculty, w h i c h is i n v o l v e d in t h e a c q u i s i t i o n a n d u s e of n a t u r a l l a n g u a g e . T h e p r i n c i p l e s of o p e r a t i o n of this faculty are said to b e distinct f r o m t h o s e of o t h e r p s y c h o l o g i c a l f a c u l t i e s , c o n t a i n i n g a g o o d deal of i n f o r m a tion a b o u t n a t u r a l l a n g u a g e s . In fact C h o m s k y ' s v i e w is that m u c h of o u r linguistic k n o w l e d g e is i n n a t e , b e i n g e m b o d i e d in t h e s t r u c t u r e of t h e l a n g u a g e f a c u l t y . W h e n a child a c q u i r e s its first l a n g u a g e , this is n o t s o m u c h a m a t t e r of l e a r n i n g as of the 3

S e e e . g . his Language and Problems of Knowledge (Cambridge, M a s s . : MIT P r e s s , 1 9 8 8 ) . F o r a m o r e d e t a i l e d , b u t still i n t r o d u c t o r y , e x p o s i t i o n o f C h o m s k y ' s i d e a s t h a n t h a t g i v e n h e r e , s e e V . J. C o o k , Chomsky's Universal Grammar ( O x f o r d : Blackwell, 1988). 3

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language faculty being triggered into s p o n t a n e o u s growth. C h o m s k y c o n c e d e s , of c o u r s e , t h a t s o m e e x p o s u r e to E n g l i s h is n e c e s s a r y if t h e c h i l d is t o g r o w u p s p e a k i n g that l a n g u a g e r a t h e r t h a n F r e n c h or J a p a n e s e . B u t h e d e n i e s that this is all a m a t t e r of l e a r n i n g — t h e child o n l y h a s to l e a r n t h e w o r d s of t h e l a n g u a g e ( t h e l e x i c o n ) , n o t t h e g r a m m a r . H e is t h e r e f o r e c o m m i t t e d to t h e t h e o r y of local t r i g g e r i n g of i n n a t e k n o w l e d g e , w h i c h w e d i s t i n g u i s h e d f r o m o t h e r v a r i e t i e s of n a t i v i s m in chapter 4. It m i g h t b e o b j e c t e d that t h e r e c a n b e n o w a y of t e s t i n g C h o m s k y ' s h y p o t h e s i s . F o r o n c e w e a l l o w that i n n a t e k n o w l e d g e m a y b e locally triggered b y e x p e r i e n c e of the d o m a i n that it c o n c e r n s , h o w a r e w e to tell, in a n y particular i n s t a n c e , w h e t h e r t h e k n o w l e d g e h a s b e e n l e a r n e d or t r i g g e r e d ? B u t , in fact, t h e g e n e r a l p o i n t a b o u t a m e c h a n i s m of l e a r n i n g is that t h e final state of t h e s y s t e m s h o u l d b e a direct p r o d u c t of t h e initial e x p e r i e n c e , c o - v a r y i n g w i t h it. In c o n t r a s t , a m e c h a n i s m of local t r i g g e r i n g will m a l f u n c t i o n in t h e f a c e o f initial e x p e r i e n c e s for w h i c h its o p e r a t i v e a s s u m p t i o n s fail to h o l d . S o if o u r k n o w l e d g e of t h e g r a m m a t i c a l b a s i s of n a t u r a l l a n g u a g e s is locally t r i g g e r e d , t h e n w e m a y p r e d i c t that a child e x p o s e d o n l y to a n artificially c o n s t r u c t e d l a n g u a g e will e i t h e r fail to learn it at all, or will o n l y d o s o e x t r e m e l y s l o w l y by c o m p a r i s o n w i t h n o r m a l l a n g u a g e a c q u i s i t i o n . H o w e v e r , a s this e x a m p l e m a k e s clear, direct t e s t i n g of t h e i s s u e m a y b e r u l e d o u t o n m o r a l g r o u n d s . In settling t h e q u e s t i o n w h e t h e r s o m e i t e m of k n o w l e d g e is l e a r n e d o r locally t r i g g e r e d , w e shall o f t e n h a v e to rely u p o n indirect arguments. H o w e v e r , this n e e d n o t m e a n that w e c a n n o t s o m e t i m e s f o r m r e a s o n a b l e b e l i e f s o n t h e m a t t e r . In p a r t i c u l a r , w h e r e v e r it is h a r d to s e e h o w o u r k n o w l e d g e of s o m e d o m a i n c o u l d h a v e b e e n a c q u i r e d f r o m o u r e x p e r i e n c e via a n y c o m b i n a t i o n of m e m o r y , i n d u c t i v e e x t r a p o l a t i o n , a n d i n f e r e n c e to t h e b e s t e x p l a n a t i o n , t h e n w e s h a l l h a v e r e a s o n to b e l i e v e t h a t local t r i g g e r i n g h a s o c c u r r e d . A s w e shall s e e in t h e n e x t s e c t i o n , this is j u s t w h a t C h o m s k y c l a i m s . H e i n s i s t s that a c h i l d ' s m a t u r e k n o w l e d g e o f its n a t i v e l a n g u a g e will g o w e l l b e y o n d a n y t h i n g that it c o u l d h a v e l e a r n e d f r o m its l i m i t e d e x p o s u r e to that language. C r u c i a l in t h e d e v e l o p m e n t of C h o m s k y ' s i d e a s h a s b e e n t h e

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d i s c o v e r y of w h a t h e calls 'linguistic u n i v e r s a l s ' . T h e s e a r e a b s t r a c t f e a t u r e s of s y n t a x that h a v e b e e n f o u n d to b e c o m m o n to all n a t u r a l l a n g u a g e s . F o r e x a m p l e , all k n o w n l a n g u a g e s h a v e a s y n t a x that is d e p e n d e n t u p o n p h r a s e s t r u c t u r e r a t h e r t h a n , for e x a m p l e , linear w o r d o r d e r . A n d t h e b a s i c f o r m of s e n t e n c e s t r u c t u r e w i t h i n all n a t u r a l l a n g u a g e s is s u b j e c t p h r a s e - v e r b - p h r a s e ( w h e r e t h e o b j e c t of t h e v e r b is i n c o r p o r ated into the verb-phrase), rather than the form s u b j e c t - p h r a s e v e r b - p h r a s e - o b j e c t - p h r a s e e m p l o y e d in t h e artificial l a n g u a g e s of logic. C h o m s k y ' s v i e w is that t h e s e u n i v e r s a l s reflect o u r c o m m o n g e n e t i c e n d o w m e n t , g i v e n in t h e s t r u c t u r e of the l a n g u a g e faculty. 4

M o r e o v e r , e v e n w h e r e t h e r e a r e m a n i f e s t syntactical differe n c e s b e t w e e n l a n g u a g e s , C h o m s k y t h i n k s that t h e s e c a n b e s e e n as m e r e l y d i f f e r e n t s e t t i n g s in a single u n d e r l y i n g i n n a t e p a r a m e t e r . In his v i e w , a c q u i r i n g s u c h a f e a t u r e of s y n t a x will b e a m a t t e r , n o t of l e a r n i n g , b u t of s w i t c h i n g t h e p a r a m e t e r to the a p p r o p r i a t e s e t t i n g . O f c o u r s e C h o m s k y c o n c e d e s that t h e lexicon ( t h e i n d i v i d u a l w o r d s ) of o n e ' s l a n g u a g e n e e d to b e l e a r n e d , t o g e t h e r w i t h s o m e specific r u l e s of g r a m m a r . B u t h e m a i n t a i n s that this is largely a m a t t e r of l e a r n i n g t h e labels for a set of innate c o n c e p t s , m o s t c o n c e p t s t h e m s e l v e s being unlearned. I p r o p o s e to set a s i d e his v i e w s on c o n c e p t s to t h e n e x t c h a p t e r , c o n c e n t r a t i n g h e r e o n h i s n a t i v i s m in relation to s y n t a x . 5

O n e a r g u m e n t for n a t i v i s m c o n c e r n s t h e e x p l a n a t i o n of t h e e x i s t e n c e of linguistic u n i v e r s a l s t h e m s e l v e s . F o r w h y s h o u l d all n a t u r a l l a n g u a g e s h a v e f e a t u r e s in c o m m o n , u n l e s s this reflects t h e i n n a t e s t r u c t u r e of a l a n g u a g e faculty that w e all p o s s e s s ? C e r t a i n l y t h e r e d o e s n o t a p p e a r to b e a n y g e n e r a l f e a t u r e of o u r p s y c h o l o g y , n o r a n y g e n e r a l l e a r n i n g p r i n c i p l e , that c o u l d e x p l a i n w h y t h e s y n t a x of all l a n g u a g e s is p h r a s e s t r u c t u r e d e p e n d e n t . H o w e v e r , a n e q u a l l y p l a u s i b l e e x p l a n a t i o n , alternative to n a t i v i s m , exists in t h e h y p o t h e s i s of a c o m m o n origin. L e t u s s u p p o s e , a s is likely, that all h u m a n k i n d is d e s c e n d e d f r o m a c o m m o n s t o c k . T h e n t h e r e will p r o b a b l y h a v e b e e n a T o b e l i e v e in l i n g u i s t i c u n i v e r s a l s n e e d n o t , o f c o u r s e , m e a n b e l i e v i n g t h a t they h a v e i n d e p e n d e n t e x i s t e n c e — i t n e e d not m e a n accepting a n y form of platonism. 4

T h e s e p a r a m e t e r s m a y usefully be t h o u g h t of as disjunctive universals, t a k i n g t h e f o r m ' N a t u r a l l a n g u a g e s a r e c o n s t r u c t e d either like t h i s , or like t h i s , or like t h i s ' . 5

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time in t h e d i s t a n t p a s t w h e n all living h u m a n b e i n g s s p o k e t h e same language. As different groups then dispersed around the g l o b e , their l a n g u a g e w o u l d h a v e b e g u n to c h a n g e a n d d e v e l o p , in p e r h a p s radically d i f f e r e n t d i r e c t i o n s ; b u t a l w a y s , it m a y b e s u p p o s e d , r e t a i n i n g certain g e n e r a l f e a t u r e s in c o m m o n — t o d a y ' s linguistic u n i v e r s a l s .

Plato's Problem In fact C h o m s k y h i m s e l f p l a c e s g r e a t e r e m p h a s i s on t h e a r g u m e n t f r o m w h a t h e calls ' P l a t o ' s P r o b l e m ' (so n a m e d after t h e s l a v e - b o y e x a m p l e in P l a t o ' s Meno). T h e p r o b l e m is e s s e n tially this: h o w , in t h e a b s e n c e of i n n a t e n e s s , w o u l d c h i l d r e n m a n a g e to learn so much, so fast, a n d on the b a s i s of s u c h meagre exposure to t h e l a n g u a g e ? T h e i s s u e of q u a n t i t y l e a r n e d is of c o u r s e i m p o s s i b l e to m e a s u r e p r e c i s e l y , b u t s o m e s e n s e of it c a n b e g a i n e d b y g l a n c i n g at a n y c o n t e m p o r a r y w o r k in l i n g u i s t i c s . N a t u r a l l a n g u a g e s s e e m to b e g o v e r n e d by a great m a n y d i f f e r e n t syntactical r u l e s of v e r y c o n s i d e r a b l e c o m p l e x i t y . W h i l e t h e s e rules are n o t c o n s c i o u s l y k n o w n by a n a t i v e s p e a k e r of t h e l a n g u a g e , t h e y s e e m n e v e r t h e l e s s to implicitly g o v e r n linguistic b e h a v i o u r . T h e y e m e r g e , for e x a m p l e , in t h e s p e a k e r ' s j u d g e m e n t s c o n c e r n i n g w h a t c o n s t r u c t i o n s are or are n o t p e r m i s s i b l e in particular c a s e s . T h e q u e s t i o n t h e n is: h o w d o e s t h e child m a n a g e t o d i s c o v e r all t h e s e r u l e s w i t h i n t h e s p a c e of just a few years, employing only learning mechanisms, w h e n e v e n m a n y y e a r s of c o - o p e r a t i v e l a b o u r o n t h e part of l i n g u i s t s still l e a v e s m u c h of t h e g r a m m a r of n a t u r a l l a n g u a g e s c o n t r o versial? The problem becomes even more pressing w h e n one cons i d e r s t h e n a t u r e of t h e d a t a available to t h e c h i l d . A d u l t l i n g u i s t s , w h o m a y t h e m s e l v e s b e n a t i v e s p e a k e r s , will h a v e available t o t h e m a s d a t a i n t h e c o n s t r u c t i o n of their g r a m m a r s a p o t e n t i a l infinity of s e n t e n c e s of t h e l a n g u a g e . T h e y c a n call u p s e n t e n c e s at will, a n d j u d g e for t h e m s e l v e s w h e t h e r t h e y are p e r m i s s i b l e o n t h e o n e h a n d , or ill f o r m e d o n t h e o t h e r . T h e c h i l d , in c o n t r a s t , h a s t o arrive at its k n o w l e d g e of t h e g r a m m a r of its n a t i v e l a n g u a g e o n t h e basis of t h e v e r y limited s a m p l e of s e n t e n c e s to w h i c h it h a p p e n s t o h a v e b e e n e x p o s e d . M o r e o v e r ,

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it will h a v e , in g e n e r a l , o n l y p o s i t i v e data to g o o n . N o o n e explicitly tells t h e child that c e r t a i n c o n s t r u c t i o n s a r e i m p e r m i s s ible. N o r , w h e n t h e child itself s p e a k s , are its e r r o r s o f t e n c o r r e c t e d . In g e n e r a l p e o p l e s i m p l y s p e a k to c h i l d r e n , w i t h o u t a t t e m p t i n g to tell t h e m h o w to s p e a k ; a n d t h e y allow c h i l d r e n to s p e a k for t h e m s e l v e s , o n l y very rarely c o r r e c t i n g their m i s t a k e s . E v e n m o r e strikingly, i n d e e d , m u c h of t h e data available to t h e child is actually c o r r u p t (that is, u n g r a m m a t i c a l ) . T o s e e t h i s , try t a p i n g part of an o r d i n a r y c o n v e r s a t i o n ; t r a n s c r i b e it o n to p a p e r , a n d t h e n s t u d y t h e result. W h a t y o u will find is that m u c h of the c o n v e r s a t i o n will c o n s i s t of s e n t e n c e s that are n e v e r f i n i s h e d , s e n t e n c e s that start o u t in o n e direction a n d t h e n c o n c l u d e in a n o t h e r , a n d s o o n . Y e t o n this sort of b a s i s t h e child a c q u i r e s a m a s t e r y of t h e g r a m m a t i c a l r u l e s of the l a n g u a g e , w h i c h still e l u d e s c o m p l e t e d e s c r i p t i o n by l i n g u i s t s . T h i s a r g u m e n t of C h o m s k y ' s a p p e a r s e x t r e m e l y p o w e r f u l . It is i m p o s s i b l e to s e e h o w t h e child c o u l d c o n s t r u c t a n o n c o n s c i o u s m o d e l of t h e g r a m m a r of t h e l a n g u a g e , u s i n g o n l y g e n e r a l l e a r n i n g p r i n c i p l e s (such a s a n a l o g y , i n d u c t i v e extrap o l a t i o n , i n f e r e n c e to t h e b e s t e x p l a n a t i o n , a n d s o o n ) , o n t h e b a s i s of s u c h f r a g m e n t a r y a n d c o r r u p t d a t a . N o r is it e a s y to s e e h o w t h e r e c o u l d b e a n y l e a r n i n g m e c h a n i s m specific to t h e l a n g u a g e faculty that c o u l d g e n e r a t e k n o w l e d g e of g r a m m a r f r o m s u c h data w i t h o u t p r e s u p p o s i n g a n y t h i n g a b o u t t h e s t r u c t u r e s of n a t u r a l l a n g u a g e s . It a p p e a r s that Plato's P r o b l e m in t h e c a s e of l a n g u a g e c a n o n l y b e s o l v e d if w e s u p p o s e that m u c h of t h e c h i l d ' s g r a m m a t i c a l k n o w l e d g e is a l r e a d y i n n a t e . T h e child w o u l d t h e n o n l y h a v e to l e a r n the l e x i c o n of its l a n g u a g e a n d a f e w g r a m m a t i c a l r u l e s that a r e l a n g u a g e specific, p r o v i d e d that it h a s sufficient e x p o s u r e to i n s t a n c e s of s e n t e n c e s of t h e l a n g u a g e to s e t t h e v a r i o u s p a r a m e t e r s w i t h i n its i n n a t e l a n g u a g e f a c u l t y . T h i s l o o k s like a m a n a g e a b l e task. T h e r e is a particular d e v e l o p m e n t of t h e a b o v e a r g u m e n t that C h o m s k y also e m p l o y s . T h i s is that c h i l d r e n s i m p l y d o n o t m a k e t h e sorts of m i s t a k e t h a t o n e w o u l d e x p e c t t h e m t o , if t h e y w e r e a r r i v i n g at their k n o w l e d g e of t h e l a n g u a g e t h r o u g h g e n e r a l l e a r n i n g p r i n c i p l e s . C o n s i d e r , for e x a m p l e , h o w t h e child l e a r n s to c o n s t r u c t q u e s t i o n s f r o m t h e c o r r e s p o n d i n g d e c l a r a t i v e s e n t e n c e s . It first h a s e x p e r i e n c e of s i m p l e s e n t e n c e s s u c h a s ' T h e m a n is at h o m e ' a n d ' T h e m a n is h a p p y ' , n o t i c i n g

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t h a t t h e c o r r e s p o n d i n g q u e s t i o n s a r e 'Is t h e m a n at h o m e ? ' a n d 'Is t h e m a n h a p p y ? ' r e s p e c t i v e l y . A t this s t a g e t h e s i m p l e s t , m o s t o b v i o u s c a n d i d a t e for t h e rule of q u e s t i o n f o r m a t i o n is to r e m o v e t h e first o c c u r r e n c e of t h e w o r d ' i s ' (or its c o g n a t e s ) to t h e f r o n t of t h e s e n t e n c e , l e a v i n g t h e s e n t e n c e o t h e r w i s e u n c h a n g e d . O n e might then expect that w h e n faced with the task of c o n s t r u c t i n g t h e q u e s t i o n c o r r e s p o n d i n g to t h e s e n t e n c e ' T h e m a n , w h o is h a p p y , is at h o m e ' , a child m i g h t try 'Is t h e m a n , w h o h a p p y , is at h o m e ? ' B u t n o child e v e r s a y s s u c h a t h i n g ! T h e n e x t m o s t o b v i o u s c a n d i d a t e for t h e rule w o u l d b e to r e m o v e t h e final o c c u r r e n c e of t h e w o r d ' i s ' to t h e front of t h e sentence, leaving the sentence otherwise u n c h a n g e d . But a p p l y i n g this rule to t h e s e n t e n c e ' T h e m a n is at h o m e , w h o is h a p p y ' w o u l d p r o d u c e 'Is t h e m a n is at h o m e , w h o h a p p y ? ' B u t n o child e v e r m a k e s this sort of m i s t a k e e i t h e r ! O f c o u r s e t h e c o r r e c t r u l e , as C h o m s k y p o i n t s o u t , is n o t l i n e a r , as t h e s e a r e , b u t p h r a s e s t r u c t u r e - d e p e n d e n t . T h e rule is that o n e s h o u l d r e m o v e t h e o c c u r r e n c e of ' i s ' f r o m t h e m a i n v e r b (the v e r b of t h e m a i n v e r b - p h r a s e ) to t h e front of t h e s e n t e n c e . F o r in reality t h e s e n t e n c e ' T h e m a n , w h o is h a p p y , is at h o m e ' h a s t h e s t r u c t u r e ' [ [ T h e m a n ] [ w h o is h a p p y ] ] is at h o m e ' , w h e r e the outer brackets enclose the subject-phrase. Similarly, t h e s e n t e n c e ' T h e m a n is at h o m e , w h o is h a p p y ' c a n b e r e p r e s e n t e d as h a v i n g t h e f o r m ' [ T h e m a n ] is at h o m e [ w h o is h a p p y ] ' , w h e r e t h e b r a c k e t s collectively e n c l o s e t h e s u b j e c t p h r a s e . S i n c e t h e s e s t r u c t u r e s a r e a m o n g s t t h e last that o n e might have expected, had one been employing only general l e a r n i n g p r i n c i p l e s , t h e i n f o r m a t i o n t h a t n a t u r a l l a n g u a g e s are p h r a s e s t r u c t u r e - d e p e n d e n t (as w e l l a s m u c h e l s e b e s i d e s ) m u s t b e s u p p o s e d to b e i n n a t e to t h e l a n g u a g e f a c u l t y . S o m e o n e m i g h t b e i n c l i n e d to o b j e c t a g a i n s t C h o m s k y that g r a m m a r ( t h e g r a m m a r of E n g l i s h , f o r e x a m p l e ) is explictly t a u g h t , o f t e n in s c h o o l s . I n d e e d , a r e n o t t h e letter c o l u m n s of n e w s p a p e r s full of c o m p l a i n t s that g r a m m a r is inadequately t a u g h t ? H o w , t h e n , c a n C h o m s k y c l a i m that c h i l d r e n a c q u i r e a n e a r - p e r f e c t g r a s p of it b y a n early a g e ? B u t this is a m i s u n d e r s t a n d i n g . In t h e v i e w o f C h o m s k y , a s of m o s t c o n t e m p o r a r y l i n g u i s t s , t h e v a r i o u s dialects o f E n g l i s h c o n s t i t u t e a u t o n o m o u s l a n g u a g e s , w i t h t h e i r o w n r u l e s of s e n t e n c e c o n s t r u c t i o n . It is o n l y for political r e a s o n s t h a t w e select o n e of t h e s e d i a l e c t s as

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p r i m a r y , a n d try to i m p o s e it u n i f o r m l y a c r o s s all s e c t i o n s of t h e c o m m u n i t y . S o C h o m s k y ' s r e p l y to t h e o b j e c t i o n w o u l d b e that c h i l d r e n d o i n d e e d h a v e a n e a r - p e r f e c t g r a s p of t h e g r a m m a r of t h e i r n a t i v e E n g l i s h dialect at a n e a r l y a g e ; w h a t t h e y a r e t h e n r e q u i r e d to m a s t e r i n s c h o o l is t h e g r a m m a r of another dialect, w h i c h t h e y h a v e to l e a r n a l m o s t a s t h e y l e a r n a f o r e i g n language.

Are Grammars Known? W e m a y a g r e e that in s o m e s e n s e or o t h e r a m a t u r e s p e a k e r of a l a n g u a g e h a s s u c c e e d e d in i n t e r n a l i z i n g t h e g r a m m a r of that l a n g u a g e . F o r s u c h a s p e a k e r h a s t h e ability to tell, of a n y c a n d i d a t e s e n t e n c e of t h e l a n g u a g e , w h e t h e r or n o t it is s y n t a c t i c a l l y well f o r m e d . T h e r e m u s t t h e n b e a n i n t e r n a l s t r u c t u r e that e x p l a i n s this ability, in s o m e w a y c o r r e s p o n d i n g to t h e r u l e s c o n s t r u c t e d b y l i n g u i s t s . B u t is it a p p r o p r i a t e to d e s c r i b e t h e o r d i n a r y s p e a k e r a s knowing t h e g r a m m a r of their l a n g u a g e ? S h o u l d w e s a y that t h e i n n a t e s t r u c t u r e of t h e l a n g u a g e faculty p r o v i d e s u s w i t h locally t r i g g e r e d i n n a t e knowledge of t h e s y n t a c t i c a l rules g o v e r n i n g o u r n a t i v e l a n g u a g e ? C h o m s k y a r g u e s at s o m e l e n g t h that w e s h o u l d , i n s i s t i n g that w e a r e h e r e d e a l i n g w i t h a g e n u i n e s p e c i e s of i n n a t e — a l t h o u g h non-conscious—knowledge. 6

It is w o r t h n o t i c i n g that if w e a c c e p t t h e p o s i t i o n a r g u e d for in t h e p r e v i o u s s e c t i o n , t h e n in a n y c a s e w e shall b e p r o v i d e d with some locally t r i g g e r e d i n n a t e k n o w l e d g e . F o r e x a m p l e , y o u r k n o w l e d g e i n t h e particular c a s e t h a t 'Is t h e m a n , w h o h a p p y , is at h o m e ? ' is n o t a p e r m i s s i b l e q u e s t i o n - f o r m w o u l d c o n s t i t u t e j u s t s u c h k n o w l e d g e . F o r y o u k n o w this w i t h o u t b e i n g t o l d , a n d w i t h o u t h a v i n g l e a r n e d it f r o m y o u r e x p e r i e n c e of t h e l a n g u a g e . T h i s is n o t at i s s u e . W h a t is at i s s u e is w h e t h e r t h e u n d e r l y i n g s y s t e m s o f r u l e s , w h i c h g e n e r a t e this p a r t i c u l a r i t e m of k n o w l e d g e , m a y b e said to b e k n o w n i n t h e i r t u r n . C h o m s k y c o n t r a s t s h i s c l a i m t h a t w e h a v e k n o w l e d g e of grammatical rules with the idea that our grasp of t h e m c o n s t i t u t e s , r a t h e r , a practical capacity, or skill. H e p r e s e n t s a n u m b e r of a r g u m e n t s a g a i n s t t h e latter h y p o t h e s i s . I n t h e first 6

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p l a c e h e p o i n t s out t h a t t w o p e o p l e c a n h a v e exactly t h e s a m e k n o w l e d g e of E n g l i s h , w h i l e d i f f e r i n g greatly in their ability t o u s e it. F o r e x a m p l e , o n e m a y b e a n a c c o m p l i s h e d a n d c r e a t i v e p u b l i c s p e a k e r , w h e r e a s t h e s p e e c h of t h e o t h e r is p e d e s t r i a n a n d b a n a l . Y e t t h e y e a c h h a v e t h e s a m e k n o w l e d g e of t h e g r a m m a r of E n g l i s h , for e x a m p l e a g r e e i n g as to w h i c h s e n t e n c e s a r e or a r e n o t well f o r m e d . But h e r e C h o m s k y h a s p i c k e d o n a d i f f e r e n t ability to t h e o n e i n t e n d e d . T h e skill that C h o m s k y ' s o p p o n e n t c o n t r a s t s w i t h o u r s u p p o s e d k n o w l e d g e of t h e g r a m m a r of E n g l i s h is not the ability to u s e E n g l i s h well, or c r e a t i v e l y . It is s i m p l y the ability to p r o d u c e , a n d to r e c o g n i z e , s e n t e n c e s of E n g l i s h that are g r a m m a t i c a l . A n d in this r e s p e c t there may be n o difference whatever between the creative and t h e dull s p e a k e r . C h o m s k y a l s o cites the c a s e of p e o p l e w h o s u f f e r c o m p l e t e a p h a s i a a f t e r a h e a d - w o u n d , l o s i n g all ability to s p e a k or to u n d e r s t a n d their n a t i v e l a n g u a g e . B u t t h e n , as t h e e f f e c t s of t h e i n j u r y r e c e d e , t h e y m a y r e c o v e r their ability to u n d e r s t a n d w i t h o u t a n y r e l e v a n t i n s t r u c t i o n or e x p e r i e n c e . W h a t this s h o w s , C h o m s k y t h i n k s , is that s i n c e p e o p l e can retain their k n o w l e d g e o f t h e l a n g u a g e w h i l e losing their ability to u s e it, o u r g r a s p of g r a m m a t i c a l rules c a n n o t s i m p l y b e a m a t t e r of ability, b u t is a g e n u i n e i n s t a n c e of k n o w l e d g e . W h a t h e fails to n o t i c e , h o w e v e r , is that o n e c a n retain the categorical basis of a c a p a c i t y , w h i l e c i r c u m s t a n c e s p r e v e n t that c a p a c i t y from b e i n g e x e r c i s e d . (To say that s o m e t h i n g h a s a c a p a c i t y is to s a y that it will b e h a v e in a c e r t a i n w a y / / c e r t a i n o t h e r t h i n g s h a p p e n . T h e categorical b a s i s o f a c a p a c i t y is t h e p o s i t i v e — n o n - h y p o t h e t i c a l — f a c t that e x p l a i n s why t h e t h i n g w o u l d b e h a v e in that w a y in those hypothetical circumstances.) F o r e x a m p l e , c o n s i d e r t h e b r i t t l e n e s s of a g l a s s , w h i c h is a m a t t e r o f its c a p a c i t y to b e b r o k e n easily (it will b r e a k if y o u hit it). T h i s c a p a c i t y h a s a categorical b a s i s , p r e s u m a b l y in t h e m o l e c u l a r s t r u c t u r e of t h e g l a s s , w h i c h e x p l a i n s w h y e v e n m o d e s t l y s e v e r e i m p a c t will s h a t t e r it. N o w s u p p o s e that t h e g l a s s h a s b e e n tightly p a c k e d in c o t t o n w o o l . O f c o u r s e it r e t a i n s its b r i t t l e n e s s (its m o l e c u l a r s t r u c t u r e r e m a i n s u n c h a n g e d ) . B u t a s a m a t t e r of fact it is n o l o n g e r e a s y to b r e a k it. S o m e t h i n g similar m a y also b e true in t h e c a s e of t e m p o r a r y a p h a s i a . It m a y b e that t h e categorical b a s i s in t h e b r a i n o f t h e p e r s o n ' s ability to

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c o n s t r u c t a n d to r e c o g n i z e g r a m m a t i c a l s e n t e n c e s r e m a i n s u n d a m a g e d , b u t t h a t t h e m e c h a n i s m s t h a t a l l o w t h i s ability t o b e e x e r c i s e d are n o l o n g e r o p e r a t i v e . In a d d i t i o n to t h e a r g u m e n t s a b o v e , C h o m s k y s e e m s to a s s u m e t h a t a n y o n e h o l d i n g t h e t h e s i s that o u r g r a s p of g r a m m a r is a practical c a p a c i t y will also b e a n o p p o n e n t of n a t i v i s m . H e a p p a r e n t l y t h i n k s that s u c h a t h e s i s m u s t g o t o g e t h e r w i t h a p i c t u r e of l a n g u a g e - l e a r n i n g as a m e r e m a t t e r of habituation, of d e v e l o p i n g a skill t h r o u g h r e p e t i t i v e activity. B u t t h e r e is n o r e a s o n w h y t h e s e i d e a s s h o u l d b e c o n n e c t e d . W e c o u l d a g r e e w i t h C h o m s k y ' s a r g u m e n t s for t h e i n n a t e n e s s of t h e l a n g u a g e faculty (as i n d e e d I h a v e ) . W e c o u l d also a g r e e that t h e categorical b a s i s of a m a t u r e s p e a k e r ' s g r a s p of their l a n g u a g e m u s t b e s t r u c t u r e d in a w a y that reflects t h e s y s t e m s of r u l e s d e v e l o p e d b y l i n g u i s t s . For h o w o t h e r w i s e are w e to e x p l a i n t h e productivity of their ability (that is, their ability to p r o d u c e , a n d to r e c o g n i z e a s g r a m m a t i c a l , s e n t e n c e s p r e v i o u s l y u n e n c o u n tered)? Y e t w e c a n c o m b i n e all this w i t h a denial of C h o m s k y ' s claim that this categorical b a s i s — s t r u c t u r e d t h o u g h it m a y b e — is a p p r o p r i a t e l y d e s c r i b e d as a s y s t e m of k n o w l e d g e . T h e m o t i v e for s u c h a d e n i a l is a s f o l l o w s . Recall that k n o w l e d g e i m p l i e s belief. S o C h o m s k y ' s claim r e q u i r e s s p e a k e r s to b e c r e d i t e d w i t h n o n - c o n s c i o u s b e l i e f s c o n c e r n i n g t h e g r a m m a t i c a l r u l e s that g o v e r n their n a t i v e l a n g u a g e . N o w t h e r e is n o o b j e c t i o n in p r i n c i p l e to t h e idea of n o n - c o n s c i o u s b e l i e f s . F o r e x a m p l e , c o n s i d e r a cyclist w h o s u c c e s s f u l l y n e g o t i a t e s o b s t a c l e s in t h e r o a d w h i l e their c o n s c i o u s a t t e n t i o n is w h o l l y directed elsewhere. T h u s I might yesterday have b e e n thinking so h a r d a b o u t t h e c o n t e n t of this c h a p t e r that I w a s u n a w a r e of w h a t I w a s s e e i n g w h i l e I c y c l e d , so that if y o u h a d a s k e d m e e v e n a m o m e n t later I s h o u l d h a v e b e e n u n a b l e to s a y w h a t I h a d b e e n d o i n g o n t h e r o a d . Y e t a n o b s e r v e r w o u l d s a y that I m u s t h a v e seen t h e v e h i c l e p a r k e d b y t h e side of t h e r o a d , s i n c e I t u r n e d t h e h a n d l e b a r s to a v o i d it. In a c a s e s u c h as this it s e e m s right to s a y that I h a d a n o n c o n s c i o u s belief that t h e r e w a s a v e h i c l e t h e r e . B u t n o t i c e that this is b e c a u s e t h e e x p l a n a t i o n of m y b e h a v i o u r fits n e a t l y i n t o the p r a c t i c a l - r e a s o n i n g - m o d e l . It is b e c a u s e I wanted to r e a c h m y d e s t i n a t i o n safely, a n d believed that t h e r e w a s a v e h i c l e in t h e w a y , a n d believed that u n l e s s I t u r n e d t h e h a n d l e b a r s I s h o u l d hit

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it, that I a c t e d a s I d i d . It s e e m s e s s e n t i a l to t h e v e r y n o t i o n of b e l i e f ( w h e t h e r c o n s c i o u s or n o n - c o n s c i o u s ) t h a t b e l i e f s a r e s t a t e s that are a p t to i n t e r a c t in a distinctive w a y w i t h o t h e r s t a t e s of d e s i r e a n d belief in s u c h a w a y a s to c a u s e a c t i o n . Y e t it is t h i s p a t t e r n of i n t e r a c t i o n that is a p p a r e n t l y m i s s i n g in t h e c a s e of o u r s u p p o s e d belief in t h e r u l e s of g r a m m a r . A n o t h e r w a y of p u t t i n g the p o i n t is that t h e s t r u c t u r e s that u n d e r l i e o u r g r a s p of g r a m m a r d o n o t h a v e t h e sort of flexibility of b e h a v i o u r a l e f f e c t that w o u l d b e n e c e s s a r y for t h e m to qualify as b e l i e f s . A n y g e n u i n e belief of y o u r s c a n lead y o u to d o o n e t h i n g , g i v e n that y o u h a v e o n e d e s i r e , or to d o s o m e t h i n g quite d i f f e r e n t , g i v e n that you h a v e a n o t h e r . If I b e l i e v e that t h e ice o n a n e a r b y p o n d is t h i n , this m a y lead m e to p u t a w a y m y s k a t e s , if m y d e s i r e is s a f e t y ; or to p u t t h e m o n , if I w a n t to c o u r t d a n g e r ; or to say to m y w i f e ' T h a t is a g o o d p l a c e to s k a t e ' if I w a n t to collect t h e i n s u r a n c e o n h e r life. T h e r e is n o t h i n g a n a l o g o u s to this in c o n n e c t i o n with o u r m a t u r e g r a s p of t h e g r a m m a r of o u r n a t i v e l a n g u a g e . T r u e e n o u g h , if w e w a n t to a c h i e v e o n e e f f e c t w e will s a y o n e t h i n g , a n d if w e w a n t to a c h i e v e s o m e t h i n g d i f f e r e n t w e will s a y s o m e t h i n g d i f f e r e n t . B u t t h e r e l e v a n t b e l i e f s h e r e will n o t b e c o n c e r n e d w i t h t h e r u l e s of g r a m m a r , b u t r a t h e r that to s a y s u c h - a n d - s u c h in t h e s e c i r c u m s t a n c e s will a c h i e v e s u c h - a n d - s u c h an effect. O u r g r a s p of g r a m m a t i c a l i t y will b e equally i m p l i c a t e d in a n y c a s e , u n d e r l y i n g in t h e s a m e w a y w h a t e v e r it is that w e c h o o s e to s a y . If w e really did h a v e beliefs a b o u t t h e detailed g r a m m a r of o u r l a n g u a g e , u n d e r l y i n g o u r ability to p r o d u c e g r a m m a t i c a l s e n t e n c e s , t h e n o n e w o u l d e x p e c t that t h e y c o u l d b e d e p l o y e d e q u a l l y in t h e s e r v i c e of wttgrammaticality. F o r c o m p a r e : y o u r beliefs a b o u t t h e l a y o u t of a p a r t i c u l a r b u i l d i n g (if true) a r e w h a t e n a b l e y o u to find y o u r w a y a r o u n d it. B u t t h e y will b e equally s e r v i c e a b l e if y o u w i s h to give t h e a p p e a r a n c e of b e i n g lost, e n a b l i n g y o u to w a n d e r f r o m o n e corridor to a n o t h e r w i t h o u t e v e r r e a c h i n g y o u r d e s t i n a t i o n . In c o n t r a s t , w e d o n o t h a v e a finely t u n e d ability to p r o d u c e u n g r a m m a t i c a l s e n t e n c e s to o r d e r . If a s k e d to d o s o , w e m o s t l y h a v e to r e s o r t to v e r y c r u d e m e t h o d s , such as constructing a random sequence of n o u n s ('Lion tiger s t a g ' ) . T h i s l o o k s m u c h m o r e like t h e difficulty a p r a c t i s e d cyclist e n c o u n t e r s if a s k e d to ride their b i c y c l e badly. T h e b e s t that m o s t of u s c a n d o h e r e is to w o b b l e a bit a n d t h e n fall off. (It t a k e s t r a i n i n g t o b e c o m e a c l o w n . )

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It is n o t e a s y for t h o s e w h o p o s s e s s a skill to b e h a v e a s if it w e r e a b s e n t , w h e r e a s it g e n e r a l l y is e a s y for t h o s e w h o h a v e a b e l i e f to b e h a v e a s if t h e y l a c k e d it. In this r e s p e c t o u r g r a s p of t h e r u l e s of g r a m m a r s e e m s m u c h m o r e like a practical ability t h a n a set of b e l i e f s . I t h e r e f o r e c o n c l u d e that, w h i l e C h o m s k y is correct in c l a i m i n g that m u c h of o u r g r a s p of l a n g u a g e is i n n a t e , h e is w r o n g w h e n h e s a y s that t h e m e n t a l s t r u c t u r e s that c o n s t i t u t e that g r a s p s h o u l d b e c o u n t e d as i n n a t e k n o w l e d g e . ( I n d e e d , h e m a y e v e n b e w r o n g in t h i n k i n g that g r a m m a t i c a l r u l e s a r e explicitly r e p r e s e n t e d in t h e m a t u r e s t r u c t u r e of t h e l a n g u a g e f a c u l t y . R a t h e r , they m a y b e implicit in its m o d e of o r g a n i z a t i o n , in s u c h a w a y that t h e s y s t e m b e h a v e s in a c c o r d a n c e w i t h t h o s e r u l e s , but w i t h o u t actually c o n s u l t i n g them. ) 7

S t r u c t u r e in V i s i o n T h e r e is a c a s e for t h i n k i n g that m a n y o t h e r faculties b e s i d e s language have innate constituent structures, e m b o d y i n g inf o r m a t i o n a b o u t t h e w o r l d . H e r e I c a n o n l y g e s t u r e at s o m e o f a rich b o d y of e v i d e n c e c o n c e r n i n g t h e faculty of vision in particular. First, it a p p e a r s to b e i n n a t e l y d e t e r m i n e d that w e s h o u l d p e r c e i v e t h e w o r l d t h r e e - d i m e n s i o n a l l y . (This m a y b e w h y e v e n p h e n o m e n a l i s t s , w h o h a v e b e c o m e c o n v i n c e d that t h e r e in fact exists n o i n d e p e n d e n t reality, c o n t i n u e to see o b j e c t s a s d i s t r i b u t e d in t h r e e - d i m e n s i o n a l s p a c e a r o u n d t h e m . ) O n e a r g u m e n t for t h i s c o n c l u s i o n is t h a t it is h a r d t o i m a g i n e h o w w e m i g h t l e a r n , e m p l o y i n g o n l y g e n e r a l l e a r n i n g p r i n c i p l e s , to i n t e r p r e t t h e p a t t e r n s in a t w o - d i m e n s i o n a l v i s u a l field as r e p r e s e n t i n g o b j e c t s in t h r e e - d i m e n s i o n a l s p a c e . T h e r e a r e o f c o u r s e c u e s of v a r i o u s s o r t s , of t h e k i n d e x p l o i t e d b y l a n d s c a p e p a i n t e r s , s u c h a s p e r s p e c t i v e a n d s h a d i n g . B u t it is h a r d to s e e h o w a child w h o a s y e t h a d n o i d e a of d i s t a n c e c o u l d b e s u p p o s e d to d e d u c e that t h e s e w e r e i n d e e d c u e s to t h r e e dimensionality. It m i g h t b e o b j e c t e d that this a r g u m e n t is t o o swift. F o r it c o u l d b e m a i n t a i n e d that a c h i l d will l e a r n to i n t e r p r e t t w o dimensional images in three-dimensional terms by m o v i n g F o r d i s c u s s i o n o f t h i s i s s u e , s e e t h e p a p e r s b y C . P e a c o c k e a n d M . D a v i e s in A . G e o r g e ( e d . ) , Reflections on Chomsky ( O x f o r d : B l a c k w e l l , 1 9 9 0 ) . 7

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a r o u n d in t h e w o r l d , a n d n o t i c i n g h o w t h e t w o - d i m e n s i o n a l i m a g e c h a n g e s . In fact, h o w e v e r , t h r e e - d i m e n s i o n a l v i s i o n s e e m s to b e in p l a c e before h u m a n b a b i e s a r e c a p a b l e of i n d e p e n d e n t m o t i o n . A t least, t h e y will a t t e m p t to m o v e a w a y f r o m a visual cliff (that is, a n a p p a r e n t d r o p or d r o p r e n d e r e d safe b e h i n d glass) a s s o o n a s t h e y a r e old e n o u g h to c o n t r o l their m o v e m e n t s . M o r e o v e r , it h a s b e e n s h o w n that t h r e e - d i m e n sional vision is i n n a t e in at l e a s t s o m e o t h e r s p e c i e s . In particular, n e w - b o r n c h i c k s will stay a w a y f r o m a visual cliff, d e s p i t e h a v i n g h a d n o p r e v i o u s visual e x p e r i e n c e . C o n s i d e r a tions of simplicity t h e n s u g g e s t that t h r e e - d i m e n s i o n a l i t y is i n n a t e to h u m a n vision a l s o . 8

A d d i t i o n a l l y , the d e v e l o p m e n t of c o m p u t a t i o n a l t h e o r i e s of vision h a s m a d e it s e e m i n c r e a s i n g l y likely that s e e i n g in t h r e e d i m e n s i o n s (as well a s m u c h e l s e in o u r visual faculty) is i n n a t e l y d e t e r m i n e d . F o r a s s c i e n t i s t s h a v e b e g u n to c o n s t r u c t c o m p u t e r m o d e l s of h o w the visual faculty can w o r k o u t the details of the visual s c e n e f r o m the t w o - d i m e n s i o n a l i n f o r m a t i o n e m b o d i e d in the p a t t e r n of activation of t h e r o d s a n d c o n e s in t h e r e t i n a , it h a s b e c a m e o b v i o u s t h a t t h e s e c o m p u t a t i o n s s i m p l y c o u l d n o t b e carried o u t realistically w i t h o u t a rich b a c k g r o u n d of i n n a t e a s s u m p t i o n s . A m o n g s t t h e s e a s s u m p t i o n s is that of t h r e e - d i m e n s i o n a l i t y . O t h e r s u g g e s t e d a s s u m p t i o n s , w h o s e i n n a t e n e s s w o u l d m a k e t h e o p e r a t i o n of o u r visual faculties a g o o d deal m o r e intelligible, are that m o s t m o v i n g b o d i e s are rigid, a n d that m o s t p e r c e i v e d c h a n g e ( o n c e t h e m o v e m e n t s of o u r o w n h e a d a n d e y e s h a v e b e e n a l l o w e d for) r e s u l t s f r o m o b j e c t s m o v i n g f r o m o n e p l a c e to a n o t h e r . T h e s e h a v e t h e n r e c e i v e d d r a m a t i c c o n f i r m a t i o n in e x p e r i m e n t a l findings. 4

10

S u p p o s e , for e x a m p l e , that y o u a r e l o o k i n g at a t e l e v i s i o n s c r e e n o n w h i c h a circle is d i s p l a y e d . T h e circle t h e n c o l l a p s e s , t h r o u g h n a r r o w i n g e l l i p s e s , i n t o a straight l i n e , a n d t h e n e x p a n d s u p to a circle a g a i n . W h a t y o u will in fact see is a circle r o t a t i n g in t h r e e - d i m e n s i o n a l s p a c e ( t h e straight line b e i n g t h e B e r k e l e y d e v e l o p s a t h e o r y o f this s o r t . S e e h i s Principles, T h e g r o u n d - b r e a k i n g w o r k o n this t o p i c is D a v i d Francisco: Freeman, 1982). 8 9

C h o m s k y details Knowledge, c h . 5 . 1 0

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c a s e w h e r e y o u see t h e circle e n d - o n ) . Y o u r visual faculty s e e m s to e m b o d y t h e i n f o r m a t i o n that m o s t c h a n g e s of this sort d o i n d e e d r e s u l t f r o m t h e m o t i o n of rigid b o d i e s , r a t h e r t h a n f r o m t h e (equally p o s s i b l e ) c o l l a p s e a n d e x p a n s i o n of b o d i e s that are flexible. In a n o t h e r clear d e m o n s t r a t i o n of t h e i m p o r t a n c e of a rigidity a s s u m p t i o n , e x p e r i m e n t e r s a t t a c h e d tiny p o i n t s of light to t h e m a i n h u m a n j o i n t s in an o t h e r w i s e c o m p l e t e l y d a r k e n e d r o o m . O b s e r v e r s w e r e n e v e r t h e l e s s able to i n t e r p r e t the m o v e m e n t of t h e lights as a p e r s o n w a l k i n g . If t h e lights w e r e p o s i t i o n e d in t h e m i d d l e of t h e rigid p o r t i o n s of the l i m b s , o n t h e o t h e r h a n d , t h e n s u b j e c t s c o u l d m a k e n o s e n s e of t h e r e s u l t i n g m o v e m e n t s . A p p a r e n t l y t h e visual s y s t e m is s t r u c t u r e d in s u c h a w a y a s to a s s u m e that the lights a r e linked by rigid b o d i e s (as t h e y a r e in t h e first e x p e r i m e n t , b u t n o t in t h e s e c o n d ) . T h e r e h a v e also b e e n a n u m b e r of d r a m a t i c e x p e r i m e n t s c o n d u c t e d i n v o l v i n g a p p a r e n t m o t i o n . If a light is d i s p l a y e d at o n e p o i n t on a television s c r e e n , w h i c h is t h e n e x t i n g u i s h e d a n d r e p l a c e d by a light at a d i f f e r e n t p o i n t , w h a t y o u will in fact s e e (if t h e t i m i n g of t h e c h a n g e is correct) is t h e first light m o v i n g to t h e p o s i t i o n of t h e s e c o n d . I n d e e d , if a b a r is p o s i t i o n e d b e t w e e n t h e t w o l i g h t s , w h a t y o u will s e e is t h e first light m o v i n g a r o u n d t h e b a r to t h e p o s i t i o n of t h e s e c o n d . A n d if the first light is r e d a n d t h e s e c o n d b l u e , w h a t y o u will s e e is the light c h a n g e c o l o u r w h i l e it m o v e s . W h a t s e e m s to be h a p p e n i n g is that y o u r visual faculty a u t o m a t i c a l l y a s s u m e s that if c h a n g e s take p l a c e in w h a t y o u s e e , t h e n this will n o r m a l l y b e t h e p r o d u c t of real m o t i o n , i n t e r p r e t i n g p e r c e i v e d c h a n g e in j u s t s u c h a m a n n e r if p o s s i b l e . It is e a s y to u n d e r s t a n d f r o m a n e v o l u t i o n a r y p e r s p e c t i v e w h y t h e b a s i c s t r u c t u r e of o u r visual faculty s h o u l d b e i n n a t e . All h u m a n b e i n g s , at w h a t e v e r t i m e s a n d in w h a t e v e r p l a c e s , h a v e i n h a b i t e d a w o r l d that is basically t h e s a m e , at least in s o far as it c o n s i s t s of a r a n g e of d i f f e r e n t l y s h a p e d , m i d d l e - s i z e d , m o s t l y rigid, m o v e a b l e o b j e c t s a g a i n s t a n i m m o b i l e t h r e e - d i m e n s i o n a l b a c k g r o u n d . T h e r e a r e t h e n g r e a t a d v a n t a g e s to t h e i n d i v i d u a l , in t e r m s of b o t h t i m e a n d reliability, if t h e a p p r o p r i a t e r e p r e s e n t a t i o n a l s y s t e m is i n n a t e l y s t r u c t u r e d . F o r in that c a s e t h e i n d i v i d u a l d o e s n o t h a v e to w a s t e t i m e l e a r n i n g s u c h a s y s t e m , a n d t h e r e is n o risk o f t h e i n e v i t a b l e m i s t a k e s that w o u l d o c c u r in t h e c o u r s e of s u c h l e a r n i n g . B o t h of t h e s e facts

94

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w o u l d a p p e a r to h a v e c o n s i d e r a b l e survival v a l u e , m a k i n g t h e i n n a t e n e s s h y p o t h e s i s likely. In c o n c l u s i o n , it w o u l d s e e m that t h e classical e m p i r i c i s t s w e r e radically m i s t a k e n in d e n y i n g that o u r v a r i o u s m e n t a l faculties e m b o d y i n n a t e i n f o r m a t i o n a b o u t t h e w o r l d . N o t o n l y d o e s t h e l a n g u a g e faculty c o n t a i n i n f o r m a t i o n a b o u t h u m a n l a n g u a g e s , b u t t h e v i s u a l faculty c o n t a i n s i n f o r m a t i o n a b o u t t h e o b j e c t s in s p a c e a r o u n d u s . A n d s o m e t h i n g similar is p r o b a b l y true in c o n n e c t i o n w i t h o t h e r faculties as w e l l . Y e t t h e i n n a t e s t r u c t u r e s of t h e s e f a c u l t i e s , w h i l e g i v i n g rise to i n n a t e k n o w l e d g e of a r a t h e r p a r t i c u l a r i z e d sort ( s u c h as y o u r k n o w l e d g e that a g i v e n s e n t e n c e is ill f o r m e d ) , s h o u l d n o t in t h e m s e l v e s b e counted as knowledge.

7 The Case For Innate Concepts IN this c h a p t e r I shall c o n s i d e r t h e a r g u m e n t s for b e l i e v i n g in i n n a t e c o n c e p t s , l e a v i n g d i s c u s s i o n of i n n a t e k n o w l e d g e to c h a p t e r 8. (Recall f r o m c h a p t e r 4 that c o n c e p t s m i g h t b e i n n a t e even though n o k n o w l e d g e is, and conversely that s o m e knowledge might be innate even though no concepts are.)

Kinds of C o n c e p t Possession W e c a n d i s t i n g u i s h at least t h r e e d i f f e r e n t s e n s e s in w h i c h a c r e a t u r e m i g h t b e said to p o s s e s s a g i v e n c o n c e p t . First, this m i g h t b e said if t h e o r g a n i s m h a s a n a p p r o p r i a t e d i s c r i m i n a t o r y c a p a c i t y , b e i n g able to act differently d e p e n d i n g u p o n w h e t h e r or n o t i n s t a n c e s of that c o n c e p t a r e p r e s e n t . F o r e x a m p l e , p i g e o n s c a n l e a r n to d i s t i n g u i s h t r i a n g l e s f r o m o t h e r s h a p e s ( p e c k i n g at t r i a n g l e s , b u t n o t s q u a r e s or circles, to g a i n a r e w a r d ) . T h e y are s o m e t i m e s d e s c r i b e d in c o n s e q u e n c e a s p o s s e s s i n g t h e c o n c e p t of a t r i a n g l e . I n d e e d , p i g e o n s a r e c a p a b l e o f l e a r n i n g p e r c e p t u a l d i s c r i m i n a t i o n s that h a v e a r e m a r k a b l e d e g r e e o f s o p h i s t i c a t i o n . T h e y c a n b e t a u g h t to p e c k at a p h o t o g r a p h for f o o d o n l y if it c o n t a i n s s o m e sort of r e p r e s e n t a t i o n of a h u m a n b e i n g , w h e t h e r in the f o r e g r o u n d or b a c k g r o u n d , sitting or s t a n d i n g , profile or full-face. T h e y c a n d o t h e s a m e for p h o t o g r a p h s of w a t e r or t r e e s , or i n d e e d for p h o t o g r a p h s o f a p a r t i c u l a r p e r s o n . S u c h p i g e o n s m i g h t b e said to p o s s e s s t h e c o n c e p t human appearance, or the c o n c e p t water appearance. 1

It is d o u b t f u l , h o w e v e r , if this n o t i o n of a c o n c e p t t a k e s us v e r y far. In particular, it is d o u b t f u l w h e t h e r c o n c e p t s in this s e n s e will f i g u r e in a n y g e n u i n e b e l i e f s . T h e r e a r e t w o p o i n t s to b e m a d e h e r e . T h e first c o n c e r n s t h e n o t i o n of b e l i e f - c o n t e n t . It 1

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Thought

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is that b e l i e f s h a v e c o n t e n t s that are e s s e n t i a l l y s t r u c t u r e d o u t of r e c o m b i n a b l e e l e m e n t s . T h e belief that g r a s s is g r e e n c o n t a i n s t h e c o n c e p t s grass a n d green, w h i c h c a n e a c h f i g u r e i n m a n y o t h e r b e l i e f s , s u c h as the belief that g r a s s is i n e d i b l e or t h e belief that e m e r a l d s a r e g r e e n . I n d e e d , t h e s e s a m e c o n c e p t s c a n also o c c u r in t h e c o n t e n t of o t h e r p r o p o s i t i o n a l a t t i t u d e s s u c h as h o p e s a n d d e s i r e s , as w h e n I h o p e that t h e g r a s s will g r o w , or w a n t a g r e e n shirt. T h e o n l y c a n d i d a t e s for the c o n t e n t of t h e p i g e o n ' s belief, on t h e o t h e r h a n d , w o u l d b e ' T h e r e is a h u m a n a p p e a r a n c e h e r e ' a n d p e r h a p s ' H u m a n a p p e a r a n c e s are a s o u r c e of f o o d ' . T h e r e is n o r e a s o n to t h i n k that the c o n c e p t of a h u m a n a p p e a r a n c e is i n d e f i n i t e l y r e c o m b i n a b l e into o t h e r c o n t e n t s a n d other propositional attitudes. T h e s e c o n d p o i n t a b o u t beliefs c o n c e r n s their c a u s a l role, w h i c h h a s a l r e a d y b e e n s t r e s s e d in p r e v i o u s c h a p t e r s . It is e s s e n t i a l to b e l i e f s that t h e y s h o u l d b e c a p a b l e of i n t e r a c t i n g w i t h d e s i r e s a n d o t h e r beliefs in s u c h a w a y as to c a u s e b e h a v i o u r , w h e r e that b e h a v i o u r is t h e n s u b j e c t to t h e practicalr e a s o n i n g - m o d e l of e x p l a n a t i o n . Y e t it a p p e a r s e x t r a v a g a n t to try to e x p l a i n t h e p i g e o n ' s b e h a v i o u r by s a y i n g that it believes that the p h o t o g r a p h it is p e c k i n g c o n t a i n s a h u m a n a p p e a r a n c e , wants s o m e t h i n g to e a t , a n d believes that p e c k i n g h u m a n a p p e a r a n c e s p r o d u c e s f o o d . T h i s is b e c a u s e t h e p i g e o n ' s r e p e r t o i r e of a c t i o n is s o e x t r e m e l y l i m i t e d . T h e c a p a c i t y to d i s c r i m i n a t e h u m a n a p p e a r a n c e s p l a y s n o o t h e r p a r t in the p i g e o n ' s life t h a n in t h e p r o d u c t i o n of a p e c k i n g r e s p o n s e . T h e r e is i n s u f f i c i e n t flexibility a n d variety of b e h a v i o u r h e r e f o r u s to c o n s i d e r seriously a p p l y i n g t h e p r a c t i c a l - r e a s o n i n g - m o d e l of explanation. T h e s e c o n d p o s s i b l e s e n s e in w h i c h a n o r g a n i s m m i g h t b e said to p o s s e s s a c o n c e p t a r i s e s n a t u r a l l y o u t of t h e l i m i t a t i o n s of t h e first. W e c o u l d s a y that a c r e a t u r e p o s s e s s e s s u c h - a n d - s u c h a c o n c e p t p r o v i d e d that w e are p r e p a r e d to ascribe to it a variety of b e l i e f s or d e s i r e s that i n v o l v e that c o n c e p t , w h e r e w e t h e n u s e t h e s t a t e s w e h a v e a s c r i b e d in e x p l a n a t i o n s of t h e c r e a t u r e ' s b e h a v i o u r that fit t h e p r a c t i c a l - r e a s o n i n g - m o d e l . In this s e n s e s o m e of t h e h i g h e r m a m m a l s , at l e a s t , p o s s e s s c o n c e p t s , s i n c e w e t a k e s e r i o u s l y t h e a t t r i b u t i o n of b e l i e f s a n d d e s i r e s to t h e m . For example, w e m a y explain the behaviour of a dog by a t t r i b u t i n g to it t h e s e q u e n c e of t h o u g h t s T w a n t to g e t t h e ball.

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T h e ball is o n t h e t a b l e . If I j u m p o n t h e chair I c a n r e a c h t h e t a b l e . S o I shall j u m p o n t h e c h a i r . ' M o r e o v e r , t h e b e h a v i o u r of a d o g c e r t a i n l y e x h i b i t s a w i d e variety of w a y s in w h i c h it c a n interact w i t h a b a l l — f e t c h i n g , c h e w i n g , c h a s i n g , a n d c a t c h i n g — s u g g e s t i n g that t h e c o n c e p t of a ball (or s o m e t h i n g like it) d o e s f o r m a c o m p o n e n t in a n u m b e r of distinct c a n i n e b e l i e f s a n d desires. H o w e v e r , recall f r o m c h a p t e r 6 that beliefs a n d d e s i r e s c a n b e n o n - c o n s c i o u s . I can believe that t h e r e is a large o b s t a c l e in t h e r o a d , a n d c o n s e q u e n t l y t u r n t h e h a n d l e b a r s of m y b i c y c l e , b e c a u s e I want to r e a c h m y d e s t i n a t i o n safely a n d believe that u n l e s s I t u r n the h a n d l e b a r s I shall c r a s h — a l l w i t h o u t c o n s c i o u s a w a r e n e s s o f w h a t I a m d o i n g or w h y . T h i s t h e n g i v e s u s o u r third p o s s i b l e s e n s e of c o n c e p t p o s s e s s i o n , w h e r e a n o r g a n i s m m a y b e said to p o s s e s s a g i v e n c o n c e p t p r o v i d e d that it e n t e r t a i n s conscious t h o u g h t s in w h i c h that c o n c e p t f i g u r e s (or is at least apt to e n t e r t a i n s u c h t h o u g h t s in a p p r o p r i a t e c i r c u m s t a n c e s ) . A sufficient c o n d i t i o n for p o s s e s s i n g a c o n c e p t in this s e n s e w o u l d b e the ability to u s e c o r r e c t l y the c o r r e s p o n d i n g t e r m of a n a t u r a l l a n g u a g e . If y o u h a v e t h e c a p a c i t y to u s e a p p r o p r i a t e l y , a n d to u n d e r s t a n d , s t a t e m e n t s in w h i c h t h e w o r d ' g r a s s ' o c c u r s , t h e n this will b e sufficient to s h o w that y o u p o s s e s s a c o n s c i o u s c o n c e p t of g r a s s . W e c a n l e a v e o p e n t h e q u e s t i o n w h e t h e r r e l e v a n t l a n g u a g e m a s t e r y is also a necessary c o n d i t i o n f o r c o n s c i o u s p o s s e s s i o n of a c o n c e p t , h e n c e l e a v i n g open the question w h e t h e r any n o n - h u m a n animals possess c o n c e p t s in o u r third s e n s e . T h e a n s w e r s to t h e s e q u e s t i o n s will d e p e n d u p o n t h e n a t u r e of t h e d i f f e r e n c e b e t w e e n c o n s c i o u s a n d n o n - c o n s c i o u s t h o u g h t , a n d o n w h e t h e r it is t r u e that o n l y language-users can entertain conscious t h o u g h t s . 2

A r m e d n o w w i t h t h e distinction b e t w e e n t h e s e t h r e e d i f f e r e n t n o t i o n s of c o n c e p t p o s s e s s i o n , w e c a n s e e i m m e d i a t e l y that o u r b a s i c r e p e r t o i r e of d i s c r i m i n a t o r y - c a p a c i t y c o n c e p t s m u s t b e i n n a t e . If w e c o u l d n o t , in t h e first p l a c e , r e s p o n d differently to stimuli of d i f f e r e n t c o l o u r s or t e m p e r a t u r e s , or to l i n e s a n d b o u n d a r i e s w i t h i n o u r visual field, t h e n w e c o u l d n e v e r learn a n y t h i n g e l s e . T h e s e e l e m e n t a l c a p a c i t i e s for d i s c r i m i n a t i o n m u s t b e built i n t o t h e v e r y s t r u c t u r e s of o u r p e r c e p t u a l O n t h e s e i s s u e s s e e m y ' B r u t e E x p e r i e n c e ' Journal Tractarian Semantics, c h . 1 0 . 2

of Philosophy,

1989, and

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apparatuses. Moreover, even w h e r e the discriminations in question are s o m e w h a t less basic (and certainly acquired over t i m e ) , s u c h a s t h e ability to tell h u m a n f a c e s a p a r t f r o m o n e a n o t h e r , it m a y b e that t h e s e d i s c r i m i n a t i o n s a r e n o t really learned. Our face-recognising mechanism may contain much i n n a t e l y d e t e r m i n e d i n f o r m a t i o n a b o u t t h e f o r m s a n d limits of e x p r e s s i o n of t h e h u m a n f a c e . S o e v e n t h e s e m a y c o u n t as i n n a t e ( b u t locally t r i g g e r e d ) c o n c e p t s . It is a l s o v e r y likely t h a t t h e b a s i c c o n c e p t u a l c o m p o n e n t s of n o n - c o n s c i o u s belief a r e i n n a t e . F o r , a s w e n o t e d t o w a r d s t h e e n d of c h a p t e r 6 in c o n n e c t i o n w i t h v i s i o n in p a r t i c u l a r , it s e e m s p l a u s i b l e that m u c h of t h e r e p r e s e n t a t i o n a l s t r u c t u r e of o u r p e r c e p t u a l faculties is i n n a t e l y fixed. T h a t w e s e e i n d i v i d u a l ( o f t e n m o v a b l e ) o b j e c t s a g a i n s t a relatively stable t h r e e - d i m e n sional b a c k g r o u n d is p r o b a b l y n o t s o m e t h i n g that w e l e a r n . In w h i c h c a s e m a n y of the v a r i o u s p e r c e p t u a l b e l i e f s that c a n g o v e r n o u r a c t i o n s w i t h o u t b e c o m i n g c o n s c i o u s will c o u n t a s e m p l o y i n g i n n a t e — t h o u g h p e r h a p s locally t r i g g e r e d — c o n c e p t s . ( A r e w e t h e n to a l l o w , in the light o f m y p r e v i o u s e x a m p l e , that t h e n o n - c o n s c i o u s c o n c e p t handlebars is i n n a t e ? T h i s s e e m s i m p l a u s i b l e . B u t t h e r e will surely b e s o m e m o r e n e u t r a l w a y of c h a r a c t e r i s i n g t h e b e l i e f that g o v e r n s m y a c t i o n s a s 1 r i d e — f o r e x a m p l e , that t u r n i n g t h e rigid b e n t s t r u c t u r e in m y h a n d s will alter m y direction of m o t i o n . H e r e t h e c o n s t i t u e n t c o n c e p t s m a y p l a u s i b l y b e said to b e i n n a t e . ) T h e beliefs in q u e s t i o n will b e t h o s e that e n a b l e u s u n r e f l e c t i v e l y to pick u p a n d t u r n o v e r o b j e c t s in o u r h a n d s , to s t e p o v e r o b s t a c l e s in o u r p a t h w h e n w a l k i n g , to turn o u r h e a d s in t h e d i r e c t i o n of a s o u n d , a n d s o on. S i n c e t h e c a s e for i n n a t e d i s c r i m i n a t o r y abilities is a p o w e r f u l o n e , as is t h e c a s e for i n n a t e r e p e r t o i r e s of n o n - c o n s c i o u s p e r c e p t u a l c o n c e p t s , all i n t e r e s t d e v o l v e s o n to t h e q u e s t i o n w h e t h e r c o n s c i o u s c o n c e p t s a r e i n n a t e . T h i s is t h e i s s u e o n w h i c h I shall c o n c e n t r a t e for t h e r e m a i n d e r o f this c h a p t e r .

Are Concepts Taught? It is c l e a r t h a t m a n y linguistic c o n c e p t s a r e u n i v e r s a l , b e i n g c o m m o n to all h u m a n s o c i e t i e s a n d t o all n a t u r a l l a n g u a g e s . B u t

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this i n itself c a n n o t p r o v i d e sufficient r e a s o n for b e l i e v i n g t h o s e c o n c e p t s t o b e i n n a t e . N o r d o w e n e e d to a p p e a l t o t h e h y p o t h e s i s of a c o m m o n historical o r i g i n to m a k e t h e p o i n t , a s w e d i d i n t h e c a s e of u n i v e r s a l f e a t u r e s of g r a m m a r i n c h a p t e r 6. F o r t h e u n i v e r s a l i t y o f s u c h c o n c e p t s is b e t t e r e x p l a i n e d b y their utility. S o c i e t i e s that did n o t h a v e c o n c e p t s of time a n d p l a c e , m o t i o n and rest, causality a n d k n o w l e d g e , would not survive for v e r y l o n g , let a l o n e p r o s p e r . O u r u n i v e r s a l c o n c e p t s c a n b e t h o u g h t of a s p r e r e q u i s i t e s for s u c c e s s f u l social life. T h e v e r y fact that m a n y of o u r c o n c e p t s h a v e a d e g r e e o f utility that m a k e s t h e m u n a v o i d a b l e d o e s , h o w e v e r , p r o v i d e s o m e slight r e a s o n f o r b e l i e v i n g t h e m to b e i n n a t e . F o r , a s w e a r g u e d in c h a p t e r 6, i n c o n n e c t i o n w i t h p e r c e p t u a l c o n c e p t s of s p a c e , t h e fact that c e r t a i n linguistic c o n c e p t s c a n b e r e g a r d e d a s a m o n g s t t h e s t a n d i n g c o n d i t i o n s of all h u m a n life m e a n s that t h e r e w o u l d b e survival v a l u e to t h e i n d i v i d u a l if t h o s e c o n c e p t s w e r e i n n a t e . T h i s w o u l d a l l o w v a l u a b l e c o g n i t i v e r e s o u r c e s in t h e d e v e l o p i n g child to b e d i r e c t e d e l s e w h e r e . It w o u l d a l s o a v o i d t h e risk of m i s t a k e s o c c u r r i n g , w h i c h a t t e n d s all l e a r n i n g . B u t t h e m o s t t h a t t h i s a r g u m e n t s h o w s is that it w o u l d n o t b e e n t i r e l y surprising if t h o s e linguistic c o n c e p t s that a r e u n i v e r s a l w e r e i n n a t e ; it d o e s n o t in itself p r o v i d e sufficient r e a s o n for believing that they are. S o m e o f t h e p o i n t s that g a v e rise t o P l a t o ' s P r o b l e m in c o n n e c t i o n w i t h t h e l e a r n i n g of g r a m m a t i c a l r u l e s h o l d in t h e c a s e of c o n c e p t - l e a r n i n g a s w e l l . C h i l d r e n a c q u i r e a h u g e n u m b e r of c o n c e p t s i n a s h o r t s p a n of t i m e . ( C h o m s k y c l a i m s t h a t at c e r t a i n p e r i o d s of c h i l d h o o d a s m a n y as a d o z e n n e w concepts are acquired each d a y . ) M o r e o v e r , they acquire these concepts on the basis of fragmentary a n d mostly positive data. F o r , j u s t a s in t h e c a s e of g r a m m a r , v e r y little explicit t e a c h i n g of c o n c e p t s actually t a k e s p l a c e . In g e n e r a l , a d u l t s s i m p l y use c o n c e p t - w o r d s in t h e p r e s e n c e of c h i l d r e n , p r o v i d i n g t h e m w i t h a s a m p l e of a p p l i c a t i o n s t h a t is n e c e s s a r i l y l i m i t e d , o n l y occasionally correcting the child's o w n mistakes. Not only this, b u t m u c h of t h e d a t a i s , f r o m t h e c h i l d ' s p o i n t of v i e w , c o r r u p t . For m u c h adult usage consists of irony, m e t a p h o r , jokes, a n d t e a s i n g , i n n o n e of w h i c h a r e c o n c e p t - w o r d s u s e d literally, a n d 3

3

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w h i c h c a n o n l y b e u n d e r s t o o d w h e n t h e literal m e a n i n g s of t h o s e w o r d s are a l r e a d y k n o w n . H o w e v e r , w e c a n n o t a s s e s s h o w p o w e r f u l t h e a n a l o g u e of P l a t o ' s P r o b l e m is in c o n n e c t i o n w i t h c o n c e p t a c q u i s i t i o n until w e h a v e a b e t t e r i d e a of w h a t c o n c e p t s t h e m s e l v e s a r e . For m u c h of t h e b u r d e n of the a r g u m e n t for t h e i n n a t e n e s s of g r a m m a r w a s t a k e n u p by t h e claim that t h e g r a m m a t i c a l r u l e s governing natural languages form a hugely subtle and complex s y s t e m . If, in c o n t r a s t , c o n c e p t s w e r e to t u r n o u t to b e relatively s i m p l e e n t i t i e s , t h e n t h e a r g u m e n t for their i n n a t e n e s s w o u l d b e c o r r e s p o n d i n g l y w e a k e r . T o this i s s u e I shall s h o r t l y r e t u r n .

F o d o r on C o n c e p t s Jerry F o d o r h a s r e c e n t l y p r o v i d e d a r g u m e n t s for t h e i n n a t e n e s s of at least m a n y o f o u r c o n s c i o u s c o n c e p t s . T h e first of t h e s e a r g u m e n t s a r i s e s o u t of a n o b j e c t i o n to e m p i r i c i s t t h e o r i e s of c o n c e p t a c q u i s i t i o n , a n d is similar to t h e o n e w e u s e d a g a i n s t L o c k e ' s a c c o u n t of a b s t r a c t i o n in c h a p t e r 4 . F o d o r c l a i m s that t h e e m p i r i c i s t v i e w m u s t b e that c o n c e p t s a r e l e a r n e d , r a t h e r t h a n m e r e l y t r i g g e r e d , a n d t h e n p o i n t s o u t t h a t t h e o n l y t h e o r y of l e a r n i n g that h a s e v e r b e e n s e r i o u s l y d e v e l o p e d i n v o l v e s h y p o t h e s i s f o r m a t i o n a n d t e s t i n g . In o r d e r to learn t h e m e a n i n g of t h e w o r d 'cat', for e x a m p l e , a child w o u l d h a v e to d o s o m e t h i n g like t h e f o l l o w i n g . It m i g h t first f o r m t h e h y p o t h e s i s that ' c a t ' m e a n s ' a n i m a l ' , a d j u s t i n g this a s f u r t h e r data b e c o m e s available ( s u c h a s a p a r e n t s a y i n g ' L o o k at that d o g ' w h e n t h e y p a s s a d o g in t h e s t r e e t ) , until finally it settles o n t h e h y p o t h e s i s that 'cat' r e f e r s to c a t s . T h e n t h e o b v i o u s p o i n t is that in o r d e r to go t h r o u g h s u c h a p r o c e d u r e , t h e c h i l d m u s t a l r e a d y h a v e a v a i l a b l e to it t h e c o n c e p t s cat a n d animal. S o if this w e r e t h e o n l y story of c o n c e p t a c q u i s i t i o n that a n e m p i r i c i s t c o u l d tell, it w o u l d follow i m m e d i a t e l y that a l a r g e r e p e r t o i r e of c o n c e p t s m u s t a l r e a d y b e i n n a t e b e f o r e a c h i l d c o u l d b e g i n to l e a r n t h e m e a n i n g s of t h e w o r d s in its n a t i v e l a n g u a g e . 4

A n a t u r a l o b j e c t i o n to this a r g u m e n t is that it a s s u m e s that p o s s e s s i o n of a linguistic c o n c e p t is a g e n u i n e i t e m of p r o p o s i t i o n a l k n o w l e d g e — a m a t t e r of k n o w i n g that a g i v e n w o r d 4

See his Representations,

ch.

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101

m e a n s s u c h - a n d - s u c h . B u t it w o u l d b e equally p l a u s i b l e (if n o t m o r e s o ) to m a i n t a i n that p o s s e s s i o n of s u c h a c o n c e p t is a practical c a p a c i t y — a m a t t e r o f k n o w i n g how to u s e a g i v e n w o r d . O n this v i e w , to p o s s e s s a c o n c e p t is to b e c a p a b l e o f c l a s s i f y i n g p r e s e n t e d i t e m s c o r r e c t l y , as well as h a v i n g t h e ability to e m p l o y t h e a p p r o p r i a t e w o r d in a variety of s e n t e n c e c o n s t r u c t i o n s . If this is r i g h t , t h e n a c q u i r i n g linguistic c o n c e p t s will b e m u c h m o r e like a c q u i r i n g a practical skill, s u c h as t h e ability to ride a b i c y c l e , t h a n it is like a c q u i r i n g a n e w i t e m of i n f o r m a t i o n . A n d n o o n e w o u l d w a n t to claim that bicycleriding is a n i n n a t e ability ( a l t h o u g h , of c o u r s e , it d o e s m a k e u s e of o u r i n n a t e c a p a c i t i e s , s u c h a s t h o s e of b a l a n c e a n d l e g movement). T h e r e a r e a n u m b e r of replies to this o b j e c t i o n available t o F o d o r . T h e first is t h a t a c q u i r i n g linguistic c o n c e p t s c a n n o t b e a m e r e m a t t e r of h a b i t u a t i o n , or r e p e t i t i v e p r a c t i c e . ( T h i s parallels C h o m s k y ' s p o i n t a b o u t t h e a c q u i s i t i o n of g r a m m a t i c a l r u l e s , d i s c u s s e d in c h a p t e r 6.) F o r o u r c o n c e p t - w o r d s a d m i t o f a n i n d e f i n i t e n u m b e r of p o s s i b l e u s e s , a n d a c o m p e t e n t s p e a k e r will b e able to u n d e r s t a n d c o m b i n a t i o n s of c o n c e p t s that t h e y h a v e h a d n o p r e v i o u s e x p e r i e n c e of. S o m e o n e w h o u n d e r s t a n d s t h e w o r d ' c a t ' , for e x a m p l e , d o e s n o t m e r e l y h a v e t h e ability to say ' c a t ' w h e n a cat is p r e s e n t , b u t a l s o to ask w h e t h e r t h e r e is a cat p r e s e n t , to a s s e r t that t h e r e is no cat p r e s e n t , a n d g e n e r a l l y to c o n n e c t that w o r d t o g e t h e r in a n i n d e f i n i t e n u m b e r of w a y s w i t h t h e o t h e r w o r d s of t h e l a n g u a g e that t h e y u n d e r s t a n d . S o e v e n if w e g r a n t that p o s s e s s i o n of a c o n c e p t c o n s i s t s in a practical c a p a c i t y , r a t h e r t h a n b e i n g a m a t t e r of g e n u i n e p r o p o s i t i o n a l k n o w l e d g e , still it m u s t b e a s p e c i a l sort of c a p a c i t y , w h o s e categorical b a s i s i n t h e b r a i n s o m e h o w reflects t h e s t r u c t u r e of t h e c o n c e p t , a n d its c o n n e c t i o n s w i t h o t h e r c o n c e p t s . A n d t h e n a c q u i r i n g that c o n c e p t c a n n o t b e m e r e l y a m a t t e r of p r a c t i s i n g a n activity, like l e a r n i n g to ride a b i c y c l e . F o d o r w o u l d also r e p l y that i n a n y c a s e all c o g n i t i v e p r o c e s s e s t a k e p l a c e in w h a t h e calls 'a l a n g u a g e o f t h o u g h t ' . T h i s w o u l d i n c l u d e t h e p r o c e s s of a c q u i r i n g t h e c a p a c i t i e s that w e are s u p p o s i n g to c o n s t i t u t e g r a s p o f linguistic c o n c e p t s . F o d o r ' s v i e w is t h a t all c o g n i t i v e p r o c e s s e s a r e computational, i n t h e s e n s e that t h e y i n v o l v e o p e r a t i o n s u p o n s e n t e n c e s or s e n t e n c e - l i k e c o n s t r u c t i o n s . H e h o l d s that t h i s is s o w h e t h e r t h e p r o c e s s e s i n

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q u e s t i o n are c o n s c i o u s or n o n - c o n s c i o u s , or w h e t h e r t h e y i n v o l v e t h e o r g a n i s m a s a w h o l e or o n l y s u b p e r s o n a l s y s t e m s s u c h a s v i s i o n or t h e details of l a n g u a g e c o m p r e h e n s i o n . S o e v e n if p o s s e s s i o n of a c o n c e p t is b e s t t h o u g h t of a s a k i n d of practical c a p a c i t y , r a t h e r t h a n a n i t e m of p r o p o s i t i o n a l k n o w l e d g e , t h e p r o c e s s of a c q u i r i n g that c a p a c i t y will still i n v o l v e h y p o t h e s i s f o r m a t i o n a n d t e s t i n g in t h e l a n g u a g e of t h o u g h t . T h e n , s i n c e all p r o c e s s e s , i n c l u d i n g t h o s e i n v o l v e d in l e a r n i n g , take p l a c e in t h e l a n g u a g e of t h o u g h t , this l a n g u a g e itself m u s t b e i n n a t e . It t h e n f o l l o w s that s o m e c o n c e p t s — n a m e l y t h e c o n c e p t s of t h e l a n g u a g e of t h o u g h t — m u s t b e i n n a t e in o r d e r that linguistic c o n c e p t s m a y b e a c q u i r e d . T h e idea of a l a n g u a g e of t h o u g h t is c o n t r o v e r s i a l . B u t , e v e n g r a n t i n g it, F o d o r ' s a r g u m e n t is less p o w e r f u l t h a n it s e e m s . F o r the m o s t that it d o e s is to force u s to r e c o g n i z e t h a t nonc o n s c i o u s b e l i e f - c o n c e p t s a r e i n n a t e , in o r d e r that c o n s c i o u s (linguistic) c o n c e p t s m a y b e a c q u i r e d . But w e h a d a l r e a d y g r a n t e d that in a n y c a s e . A n d it d o e s n o t follow that c o n s c i o u s concepts are themselves innate. I n d e e d , the appropriate conc l u s i o n m a y b e w e a k e r still. F o r it w o u l d b e m u c h m o r e p l a u s i b l e to a s s i m i l a t e t h e c o n c e p t s i n v o l v e d in c o g n i t i v e p r o c e s s i n g g e n e r a l l y to t h e d i s c r i m i n a t o r y - c a p a c i t y c o n c e p t s d i s c u s s e d earlier. F o r it is d o u b t f u l w h e t h e r c o g n i t i v e m o d e l s of hypothesis formation and testing within s o m e subpersonal m e n t a l faculty ( s u c h as that of l a n g u a g e p r o c e s s i n g ) will g e n u i n e l y fit t h e p r a c t i c a l - r e a s o n i n g - m o d e l of e x p l a n a t i o n . S o it m a y o n l y follow (if w e a c c e p t t h e i d e a of t h e l a n g u a g e of t h o u g h t ) that w e are c o m m i t t e d to the i n n a t e n e s s of s u b p e r s o n a l d i s c r i m i n a t o r y c a p a c i t i e s . B u t a g a i n , this w a s s o m e t h i n g t h a t w e h a d a c c e p t e d in a n y c a s e . T h e i n t e r e s t i n g q u e s t i o n is w h e t h e r c o n s c i o u s c o n c e p t s (or s o m e t h i n g like t h e m ) a r e i n n a t e .

F o d o r o n Definitions F o d o r d o e s h a v e a d i f f e r e n t a r g u m e n t for t h e i n n a t e n e s s of m a n y c o n s c i o u s c o n c e p t s , w h i c h t u r n s o n his c l a i m t h a t m o s t linguistic c o n c e p t s a r e in fact indefinable. F o r h e a r g u e s t h a t t h e m a i n p o i n t of c o n t e n t i o n b e t w e e n e m p i r i c i s t s a n d n a t i v i s t s a b o u t c o n c e p t s c o n c e r n s t h e r a n g e of c o n c e p t s t h a t a r e d e f i n a b l e

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in t e r m s of a p r i m i t i v e c o n c e p t u a l b a s i s . A c c o r d i n g to F o d o r , t h e e m p i r i c i s t m a i n t a i n s that all o t h e r c o n c e p t s m a y b e d e f i n e d in t e r m s o f a s e t of i n n a t e c o n c e p t s t h a t a r e sensory, that arise directly o u t of e x p e r i e n c e (the p r o c e s s of c o n s t r u c t i o n t h r o u g h d e f i n i t i o n t h e n p r o v i d i n g t h e e m p i r i c i s t s w i t h their t h e o r y of l e a r n i n g ) . T h e n a t i v i s t m a i n t a i n s , o n t h e c o n t r a r y , t h a t m o s t of our concepts are triggered rather than learned. T h e r e is o n e w a y in w h i c h F o d o r definitely g o e s w r o n g h e r e . T h i s is in h i s claim that a n e m p i r i c i s t m u s t c o u n t t h e b a s i c sensory concepts as innate (triggered by experience, rather than l e a r n e d f r o m it) b e c a u s e t h e y a r e n o t a c q u i r e d via a p r o c e s s o f h y p o t h e s i s f o r m a t i o n a n d t e s t i n g . F o r this a c c o u n t of l e a r n i n g is t o o n a r r o w . E m p i r i c i s t s s u c h a s L o c k e a n d H u m e certainly t h o u g h t that o u r b a s i c c o n c e p t s a r e l e a r n e d f r o m e x p e r i e n c e , b y v i r t u e of their b e i n g a r e c o r d of t h e initial e x p e r i e n c e laid d o w n in m e m o r y . W h a t F o d o r o v e r l o o k s is that o u r c o m m o n - s e n s e c o n c e p t of l e a r n i n g d i v i d e s i n t o at least t h r e e distinct k i n d s . T h e r e is l e a r n i n g b y m e a n s of an i n f e r e n c e to t h e b e s t e x p l a n a t i o n , w h i c h is w h a t f o r m s F o d o r ' s p a r a d i g m . B u t t h e r e is also l e a r n i n g h o w to d o s o m e t h i n g , s u c h a s ride a b i c y c l e . A n d t h e r e is m e m o r y - b a s e d l e a r n i n g , a s w o u l d o c c u r w h e n o n e c o m e s to k n o w w h a t s o m e o n e l o o k s like, b y m e e t i n g t h e m . In fact t h e early e m p i r i c i s t s p r o p o s e d t h a t b a s i c s e n s o r y c o n c e p t s are l e a r n e d in t h e third of t h e s e m o d e s , o n the b a s i s o f p r i o r a c q u a i n t a n c e . All t h e s a m e , F o d o r is quite right a b o u t t h e m a i n i s s u e , w h i c h is that it will c o u n t in f a v o u r of t h e rationalist t h e s i s that m o s t of o u r c o n c e p t s a r e i n n a t e , if it t u r n s o u t that t h e y c a n n o t b e d e f i n e d at all, let a l o n e in p u r e l y s e n s o r y t e r m s . F o d o r ' s m a i n a r g u m e n t for i n d e f i n a b i l i t y is b a s e d u p o n o u r failure, historically s p e a k i n g , to c o m e u p w i t h a g r e e d d e f i n i t i o n s . D e s p i t e g e n e r a t i o n s of c o - o p e r a t i v e l a b o u r b y analytic p h i l o s o p h e r s , t h e r e is h a r d l y a s i n g l e c o n c e p t w h o s e a n a l y s i s is g e n e r a l l y a c c e p t e d . T h e b e s t e x p l a n a t i o n of this p h e n o m e n o n , F o d o r t h i n k s , is s i m p l y t h a t t h e r e d o n o t exist a n y d e f i n i t i o n s to b e f o u n d . B u t in fact a n a l t e r n a t i v e e x p l a n a t i o n is s u g g e s t e d b y C h o m k s y . T h i s is t h a t m o s t of o u r c o n c e p t s a r e e x t r e m e l y c o m p l e x , b e i n g r e l a t e d to o n e a n o t h e r i n all sorts o f s u b t l e w a y s . T h i s s e e m s o n t h e f a c e of it to b e e q u a l l y a c c e p t a b l e . H o w e v e r , a n i n t e r e s t i n g possibility o p e n s u p h e r e . F o r it m a y b e t h a t in 5

5

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and Problems

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ch. 1.

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e i t h e r c a s e w e shall h a v e a n a r g u m e n t for n a t i v i s m . F o r C h o m s k y , in effect, t u r n s this a l t e r n a t i v e e x p l a n a t i o n of failures of d e f i n i t i o n i n t o t h e a n a l o g u e , in t h e c a s e of c o n c e p t s , of P l a t o ' s P r o b l e m for g r a m m a r a c q u i s i t i o n . S u p p o s i n g that t h e s y s t e m of c o n c e p t s of a m a t u r e s p e a k e r is v e r y subtle a n d c o m p l e x , t h e n the p r o b l e m of h o w a child m a n a g e s to a c q u i r e this s y s t e m o n s u c h a s l e n d e r b a s i s really d o e s b e c o m e p r e s s i n g . B u t in fact, e v e n s u p p o s i n g that F o d o r is right that m o s t c o n c e p t s a r e i n d e f i n a b l e , this n e e d n o t c o m m i t u s to n a t i v i s m . For, as h e h i m s e l f n o t e s , ' i n d e f i n a b l e ' d o e s n o t n e c e s s a r i l y i m p l y ' u n s t r u c t u r e d ' . It m a y b e that c o m p l e x c o n c e p t s a r e built u p out of s i m p l e r o n e s , w i t h o u t b e i n g d e f i n a b l e in t e r m s of t h e m (at least if t h e d e f i n i t i o n s are r e q u i r e d to take t h e f o r m of s t a t e m e n t s of n e c e s s a r y a n d s u f f i c i e n t c o n d i t i o n s of a p p l i c a t i o n ) . J u s t s u c h a possibility will b e realized if c o n c e p t s a r e r e p r e s e n t e d in t h e m i n d by prototypes, w h i c h is a t h e s i s for w h i c h m u c h p s y c h o logical e v i d e n c e h a s r e c e n t l y b e g u n to e m e r g e .

C o n c e p t s as P r o t o t y p e s A p r o t o t y p e is a s p e c i f i c a t i o n of a set of p r o t o t y p i c a l p r o p e r t i e s , t a k e n t o g e t h e r w i t h a w e i g h t e d similarity m e a s u r e . T h e p r o t o t y p e for the c o n c e p t dog, for e x a m p l e , w o u l d i n c l u d e s u c h f e a t u r e s as barks when angry, wags its tail when happy, is a mammal, has dogs as parents, eats bones, a n d s o o n . B u t t h e r e is n o s u g g e s t i o n that all d o g s m u s t n e c e s s a r i l y h a v e all t h e s e f e a t u r e s . R a t h e r , d e c i d i n g w h e t h e r s o m e t h i n g is a d o g is a m a t t e r of j u d g i n g w h e t h e r it is sufficiently similar to t h e p r o t o t y p i c a l d o g . F o d o r c o n s i d e r s this t h e o r y , b u t t h i n k s h e h a s a swift d i s m i s s a l of it. H e c l a i m s that it c a n n o t p r o v i d e a n a c c o u n t of c o m p o s i t i o n a l i f y — o f h o w w e c a n c o m b i n e t o g e t h e r linguistic c o n c e p t s to f o r m n e w o n e s . H e a s k s , for e x a m p l e , h o w t h e m e a n i n g of ' b r o w n c o w ' is s u p p o s e d to b e d e t e r m i n e d f r o m t h e p r o t o t y p e s of ' b r o w n ' a n d ' c o w ' . B u t t h e r e p l y is s u r e l y s t r a i g h t f o r w a r d . It is t h a t t h e m e a n i n g of ' b r o w n c o w ' m a y b e g i v e n b y 'is s u f f i c i e n t l y similar to this ( t h e p r o t o t y p e o f b r o w n ) and is sufficiently similar to this ( t h e p r o t o t y p e of c o w ) ' . T h e p o i n t is that t h e m e a n i n g s of c o m p l e x c o n c e p t s f o r m e d b y 6

6

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296-8.

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putting together individual words n e e d not themselves be p r o t o t y p e s . T h e false a s s u m p t i o n i n F o d o r ' s a r g u m e n t is that if p r o t o t y p e t h e o r y is c o r r e c t , t h e n t h e c o n c e p t s e x p r e s s e d b y lexically c o m p l e x i t e m s s u c h a s ' b r o w n c o w ' m u s t t h e m s e l v e s b e p r o t o t y p e s . R a t h e r , s u c h c o n c e p t s m a y b e logical c o n s t r u c t i o n s out of p r o t o t y p e s — b u i l d i n g t h e m u p u s i n g n o t i o n s like and a n d or. H o w e v e r , if c o n c e p t s like brown cow a r e logical c o n s t r u c t i o n s out of p r o t o t y p e s , w h e r e d o t h e s e logical n o t i o n s c o m e f r o m in their t u r n ? I t h i n k that t h e y c o u l d v e r y plausibly b e a l l o w e d b y a n e m p i r i c i s t to b e i n n a t e . T h e y can b e r e g a r d e d a s b e l o n g i n g to the g i v e n ( i n n a t e ) logical s t r u c t u r e of t h e m i n d . F o r t h e s e n o t i o n s d o n o t in t h e m s e l v e s c o n s t r a i n w h a t t h e w o r l d m a y b e like. E m p i r i c i s t s s h o u l d o n l y o b j e c t to t h e i n n a t e n e s s o f c o n c e p t s that s e e m to carry i n f o r m a t i o n a b o u t t h e w o r l d — w h e r e a s t h e logical c o n c e p t s will b e e q u a l l y a p p l i c a b l e n o m a t t e r w h a t o u r e x p e r i e n c e of t h e w o r l d m a y b e like. S o F o d o r ' s a r g u m e n t a g a i n s t t h e e m p i r i c i s t fails, e v e n g i v e n t h e w a y in w h i c h h e s e t s u p t h e d e b a t e . It m a y b e t h a t m o s t of o u r c o m p l e x c o n c e p t s a r e e i t h e r p r o t o t y p e s or logical c o n s t r u c t i o n s o u t of p r o t o t y p e s , w h e r e t h e s e in t u r n a r e c o n s t r u c t e d o u t of s i m p l e i d e a s d e r i v e d f r o m e x p e r i e n c e (but w i t h o u t b e i n g d e f i n a b l e in t e r m s of t h o s e ideas). I shall n o t n o w r e v i e w t h e p s y c h o l o g i c a l e v i d e n c e s u p p o r t i n g t h e t h e s i s that m a n y of o u r c o n c e p t s h a v e p r o t o t y p e s t r u c t u r e . R a t h e r , s u p p o s i n g that s u c h a t h e s i s is correct, let u s a s k w h e t h e r it is sufficient to d e f e n d e m p i r i c i s t t h e o r i e s o f c o n c e p t a c q u i s i t i o n . O n e p o i n t c a n b e m a d e s t r a i g h t a w a y , in t h e light of w h a t w a s said in c h a p t e r 4 . F o r it w o u l d b e j u s t a s i m p l a u s i b l e to m a i n t a i n that all c o m p l e x c o n c e p t s c a n b e constructed out of a b a s i c set of p u r e l y s e n s o r y o n e s a s it w o u l d b e to claim that t h e y c a n all b e defined in s u c h t e r m s . ( F o r e x a m p l e , try giving a p r o t o t y p i c a l set of s e n s o r y c o n c e p t s t h a t w o u l d e v e n b e g i n to b e a d e q u a t e to e x p r e s s t h e c o n c e p t o f c a u s a t i o n . ) S o if e m p i r i c i s m w e r e c o m m i t t e d to r e d u c i n g all c o n c e p t s to t h o s e t h a t d e s c r i b e o u r p r i v a t e s e n s a t i o n s , t h e n t h e i n t r o d u c t i o n of p r o t o t y p e s w o u l d b r i n g it n o p a r t i c u l a r a d v a n t a g e . H o w e v e r , recall f r o m o u r earlier d i s c u s s i o n that w e are a l l o w i n g t h e r e to b e a n i n n a t e s e t of p e r c e p t u a l b e l i e f - c o n c e p t s O n this, see G e o r g e Lakoff, Chicago University Press, 1987). 7

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t h a t , s o far f r o m b e i n g p u r e l y s e n s o r y , i n v o l v e r e p r e s e n t a t i o n s of p h y s i c a l o b j e c t s in t h r e e - d i m e n s i o n a l s p a c e . T h i s m i g h t p r o v i d e a sufficient b a s i s on w h i c h t o c o n s t r u c t c o m p l e x p r o t o t y p e s . F o r e x a m p l e , a child m i g h t first a c q u i r e , t h r o u g h e x p e r i e n c e , a p e r c e p t u a l paradigm for a g i v e n c o n c e p t . O n h e a r i n g a n o b j e c t d e s c r i b e d as a cat for t h e first t i m e , it lays d o w n a r e p r e s e n t a t i o n of that p a r t i c u l a r cat in m e m o r y . (It is this stage that presupposes innate perceptual belief-concepts.) T h e n , t h r o u g h f u r t h e r e x p e r i e n c e , it b e g i n s to a c q u i r e a similarity m e a s u r e for j u d g i n g w h e t h e r a g i v e n o b j e c t is sufficiently c l o s e to t h e p a r a d i g m to b e a cat. F o r e x a m p l e , t h e child m i g h t start b y o v e r e x t e n d i n g t h e c o n c e p t , j u d g i n g that a d o g is sufficiently c l o s e to the p a r a d i g m , until it is e i t h e r c o r r e c t e d by its p a r e n t s or h e a r s the d o g d e s c r i b e d a s s u c h . A s it b e g i n s to a c q u i r e p e r c e p t u a l p a r a d i g m s a n d similarity m e a s u r e s for o t h e r c o n c e p t s , t h e c h i l d also starts to c r o s s - c l a s s i f y , b u i l d i n g u p the full p r o t o t y p e for ' c a t ' . For e x a m p l e , h a v i n g a c q u i r e d a p a r a d i g m for 'tail', it l e a r n s that c a t s h a v e tails, a n d h a v i n g a c q u i r e d a p a r a d i g m for ' m a m m a l ' it l e a r n s t h a t c a t s are m a m m a l s , and so o n . 8

If this p i c t u r e , or s o m e t h i n g like it, p r o v e d to b e c o r r e c t , t h e n t h e e m p i r i c i s t v i e w of t h e a c q u i s i t i o n of c o n s c i o u s c o n c e p t s w o u l d b e largely v i n d i c a t e d . T h e initial p e r c e p t u a l p a r a d i g m s w o u l d b e g i v e n in e x p e r i e n c e ( a l t h o u g h r e q u i r i n g a n i n n a t e p e r c e p t u a l b a s i s ) , a n d t h e later c r o s s - c l a s s i f i c a t i o n s c o u l d also b e l e a r n e d t h r o u g h e x p e r i e n c e . T h e similarity m e a s u r e s , t o o , m i g h t b e l e a r n e d f r o m e x p e r i e n c e , if it w e r e to t u r n o u t that p a r e n t a l t e a c h i n g is crucially n e c e s s a r y to p r e v e n t c h i l d r e n f r o m o v e r e x t e n d i n g or u n d e r e x t e n d i n g their c o n c e p t s . I n d e e d , it w o u l d b e a v i r t u e of this s o r t of a c c o u n t that it c o u l d o v e r c o m e t h e p r o b l e m of a historical r e g r e s s , o u t l i n e d in c h a p t e r 4. W e n e e d o n l y s u p p o s e that t h e similarity m e a s u r e s w e r e first settled u p o n causally, r a t h e r t h a n a r r i v e d at b y prior t e a c h i n g or conscious choice. This could either have h a p p e n e d by chance, or a s a r e s u l t of s o m e similarities b e i n g m o r e s a l i e n t , or m o r e r e l e v a n t to h u m a n c o n c e r n s , t h a n o t h e r s . N o d o u b t it is a m i s t a k e to treat all c o n c e p t s as if t h e y w e r e alike. It m a y b e t h a t s o m e a r e p r o t o t y p e s , a n d are a c q u i r e d f r o m A t h e o r y o f this s o r t is d e v e l o p e d b y A n d r e w W o o d f i e l d , ' O n t h e V e r y I d e a of A c q u i r i n g a C o n c e p t ' , in J a m e s R u s s e l l ( e d . ) , Philosophical Perspectives (Oxford: Blackwell, 1987). 8

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e x p e r i e n c e , a n d that s o m e are n o t . O n e class o f c o n c e p t s for w h i c h t h e p r o t o t y p e t h e o r y l o o k s particularly i m p l a u s i b l e a r e p s y c h o l o g i c a l o n e s s u c h a s belief, desire a n d intention. (In fact, it is in c o n n e c t i o n w i t h s u c h c o n c e p t s that C h o m s k y u r g e s h i s a l t e r n a t i v e r e s p o n s e to t h e l a c k of a g r e e d d e f i n i t i o n s , o p t i n g for a n e x p l a n a t i o n in t e r m s of c o m p l e x i t y , a n d a r g u i n g for i n n a t e n e s s as t h e o n l y s o l u t i o n to P l a t o ' s P r o b l e m . ) T h e s e will c o m e i n t o f o c u s in t h e n e x t c h a p t e r , w h e r e w e c o n s i d e r t h e a r g u m e n t s for s a y i n g that o u r k n o w l e d g e of o u r o w n p s y c h o l o g y is i n n a t e , t o g e t h e r w i t h its c o n s t i t u e n t p s y c h o l o g i c a l c o n c e p t s . For t h e m o m e n t o u r c o n c l u s i o n m u s t b e that t h e c a s e for t h e i n n a t e n e s s o f c o n s c i o u s c o n c e p t s is largely u n p r o v e n . 9

The C o n c e p t of Best Explanation T h e r e is, h o w e v e r , o n e c l u s t e r of c o n c e p t s that are v e r y likely to b e i n n a t e . T h e s e a r e t h e c o n c e p t s i n v o l v e d in t h e a p p r a i s a l o f n o n - d e d u c t i v e m o d e s o f a r g u m e n t , particularly t h e c o n c e p t o f t h e b e s t available e x p l a n a t i o n of a g i v e n p h e n o m e n o n . T h i s c o n c e p t is u n d o u b t e d l y a c o n s c i o u s ( b e c a u s e linguistic) o n e , b u t it is n o t o r i o u s l y difficult to d e f i n e . Y e t t h e r e is a r e m a r k a b l e d e g r e e of a g r e e m e n t a m o n g s t s p e a k e r s in particular c a s e s a s to w h e t h e r o n e e x p l a n a t i o n is or is n o t b e t t e r t h a n a n o t h e r . M o r e o v e r , w h i l e t h e c o n c e p t d o e s to s o m e e x t e n t d i s p l a y p r o t o t y p e s t r u c t u r e (a g o o d e x p l a n a t i o n t e n d s to b e s i m p l e a n d consistent, cohere well with surrounding beliefs, h a v e broad s c o p e , be fruitful in g e n e r a t i n g n e w p r e d i c t i o n s , a n d s o o n ) , t h e c o n s t i t u e n t n o t i o n s a r e n o e a s i e r to d e f i n e in their t u r n ; n o r is it e a s y to s e e h o w t h e y m i g h t b e d e r i v e d f r o m e x p e r i e n c e . T h e n , s i n c e c h i l d r e n r e c e i v e n o explicit t r a i n i n g in t h e u s e of this c o n c e p t , w e c a n n o t e x p l a i n h o w w e n e v e r t h e l e s s m a n a g e to a c q u i r e it, u n l e s s w e s u p p o s e that t h e c o n c e p t is i n n a t e — t r i g g e r e d b y t h e c o u r s e of o u r e x p e r i e n c e , r a t h e r t h a n l e a r n e d f r o m it. It is w o r t h s t r e s s i n g t h a t w h i l e t h e c o n c e p t of b e s t e x p l a n a t i o n d o e s f i g u r e p r o m i n e n t l y in s c i e n c e , it is b y n o m e a n s a n e x c l u s i v e l y scientific i d e a . O n t h e c o n t r a r y , w e e a c h of u s c o n s t a n t l y m a k e at l e a s t tacit u s e o f it i n t h e c o u r s e o f o u r daily A n o t h e r w o u l d b e t h e c o n c e p t o f cause. I n d e e d , a s w e n o t e d i n c h a p t e r 4 , t h e r e m a y b e a p o w e r f u l c a s e for s a y i n g t h a t t h i s c o n c e p t , a t l e a s t , is i n n a t e . 9

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lives. F o r e x a m p l e , w h e n I e n t e r a l e c t u r e - h a l l full of s t u d e n t s , a n d c o n s e q u e n t l y f o r m t h e belief that t h e y h a v e c o m e to listen to m e s p e a k , this is b e c a u s e this belief p r o v i d e s , in t h e c i r c u m s t a n c e s , o v e r w h e l m i n g l y t h e b e s t a v a i l a b l e e x p l a n a t i o n for their p r e s e n c e . S c i e n t i s t s p r o b a b l y m a k e u s e of t h e v e r y s a m e c o n c e p t , d i f f e r i n g o n l y in that their s e a r c h is for t h e g e n e r a l l a w s or p r i n c i p l e s u n d e r l y i n g t h e o b s e r v a b l e p h e n o m e n a to b e explained. O n e c a n n o t m e n t i o n n o n - d e d u c t i v e m o d e s of a r g u m e n t w i t h o u t d i s c u s s i n g H u m e . For H u m e is f a m o u s for his d i s c o v e r y of t h e p r o b l e m of j u s t i f y i n g i n d u c t i o n , a n d for his naturalistic e x p l a n a t i o n of o u r u s e of it. His v i e w is that i n d u c t i o n h a s n o rational b a s i s , e i t h e r in r e a s o n or in e x p e r i e n c e . Its reliability c a n n o t b e d e m o n s t r a t e d a priori. N o r c a n it b e s h o w n to b e reliable by p a s t e x p e r i e n c e w i t h o u t c i r c u l a r i t y . O u r r e l i a n c e u p o n i n d u c t i o n is r a t h e r to b e e x p l a i n e d by a p p e a l to t h e b a s i c p r i n c i p l e s of h u m a n p s y c h o l o g y , particularly t h e l a w s of a s s o c i a t i o n a m o n g s t i d e a s . H u m e ' s t h e o r y is that h a v i n g s e e n a p h e n o m e n o n r e p e a t e d , w e a r e h a b i t u a t e d to e x p e c t it to c o n t i n u e in t h e f u t u r e . B u t this is n o t to a s c r i b e to u s a n i n n a t e c o n c e p t . F o r t h e p s y c h o l o g i c a l p r i n c i p l e s that g i v e rise to i n d u c t i o n are s u p p o s e d to b e g e n e r a l o n e s . T o say t h a t o u r p s y c h o l o g y is s u c h that w e d o , as a m a t t e r of fact, g o in for i n d u c t i o n is n o t to s a y that o u r m i n d s c o n t a i n an i n n a t e c o n c e p t of a g o o d i n d u c t i v e a r g u m e n t . 10

Q u i t e a p a r t f r o m t h e c r u d i t y of his p s y c h o l o g i c a l t h e o r y , t h e r e a r e t w o t h i n g s w r o n g w i t h H u m e ' s a c c o u n t . T h e first is that it i g n o r e s t h e normativity i n v o l v e d in o u r i d e a of b e s t e x p l a n a t i o n . T h e fact is that w e d o n o t (as a m e r e m a t t e r of fact) r e a s o n in c e r t a i n w a y s , a s a r e s u l t of o u r n a t u r e . W e also a p p l y s t a n d a r d s of a p p r a i s a l to s u c h r e a s o n i n g s , c o u n t i n g s o m e n o n - d e d u c t i v e a r g u m e n t s a s b e t t e r t h a n o t h e r s , a n d c o u n t i n g p e o p l e as right or w r o n g in their a s s e s s m e n t s of t h e m e r i t s of s u c h a r g u m e n t s . Y e t this is o n e of t h e d i s t i n c t i v e m a r k s o f p o s s e s s i o n of a c o n s c i o u s c o n c e p t . F o r , as w e n o t e d in c h a p t e r 3 , c o n c e p t s a r e b e s t c o n s t r u e d b y e m p i r i c i s t s as r u l e s of c l a s s i f i c a t i o n . T h i s s e e m s to b e j u s t w h a t w e h a v e in t h e p r e s e n t i n s t a n c e : w e h a v e a rule for c l a s s i f y i n g s o m e n o n - d e d u c t i v e a r g u m e n t s as b e t t e r t h a n others. 1 0

W e s h a l l r e t u r n t o c o n s i d e r t h e s e p o i n t s in g r e a t e r d e t a i l in c h a p t e r 1 2 .

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H u m e ' s s e c o n d m i s t a k e is that i n d u c t i o n is b y n o m e a n s t h e o n l y n o n - d e d u c t i v e m o d e of a r g u m e n t . I n d u c t i o n is a m a t t e r of g e n e r a l i z i n g or p r o j e c t i n g f r o m o b s e r v e d r e g u l a r i t i e s . Y e t w e also f r e q u e n t l y r e a s o n f r o m s u c h regularities to t h e p r e s e n c e of some underlying p h e n o m e n o n (sometimes involving unobserva b l e s , s u c h a s s u b - a t o m i c particles) that w o u l d e x p l a i n it. I n d e e d , i n d u c t i o n itself is b e s t s e e n as a particular i n s t a n c e o f t h e m o r e g e n e r a l p r a c t i c e of i n f e r r i n g to t h e b e s t e x p l a n a t i o n . T h e r e a s o n w h y w e i n f e r f r o m 'All r a v e n s s o far o b s e r v e d h a v e b e e n b l a c k ' to 'All r a v e n s a r e b l a c k ' is that t h e fact that all r a v e n s are b l a c k is t h e b e s t available e x p l a n a t i o n for w h y all observed r a v e n s s h o u l d h a v e b e e n b l a c k . Y e t t h e r e is n o q u e s t i o n o f e x h i b i t i n g i n f e r e n c e to t h e b e s t e x p l a n a t i o n a s f l o w i n g f r o m t h e g e n e r a l p r i n c i p l e s of a s s o c i a t i o n a m o n g s t i d e a s . N o r is it e a s y to s e e h o w it m i g h t b e e x p l a i n e d in t e r m s o f g e n e r a l f e a t u r e s o f a n y m o r e s o p h i s t i c a t e d p s y c h o l o g i c a l t h e o r y . Y e t all H u m e ' s r e a s o n s for t h i n k i n g that i n d u c t i o n is c o g n i t i v e l y basic a n d i n d i s p e n s able for u s n o w t r a n s f e r to t h e c a s e of i n f e r e n c e to t h e b e s t e x p l a n a t i o n . It is t h e r e f o r e plausible to s u p p o s e that w e h a v e a n i n n a t e g r a s p of t h e c o n c e p t o f b e s t e x p l a n a t i o n , w h i c h w e t h e n e m p l o y in a p p r a i s i n g particular a r g u m e n t s . It m a y b e o b j e c t e d that t h e r e a r e w i d e v a r i a t i o n s a c r o s s c u l t u r e s c o n c e r n i n g w h a t e x p l a n a t i o n s will b e c o u n t e d as b e t t e r t h a n o t h e r s . H o w , t h e n , c a n t h e c o n c e p t of b e s t e x p l a n a t i o n b e i n n a t e to t h e h u m a n s p e c i e s ? In o u r c u l t u r e , for e x a m p l e , w e e x p l a i n i l l n e s s e s in t e r m s of s u c h t h i n g s as t h e activity of v i r u s e s o n t h e b o d y , w h e r e a s in o t h e r c u l t u r e s t h e s a m e illness m a y b e e x p l a i n e d in t e r m s of t h e m a l i g n a n t a c t i o n of a w i t c h . B u t this is to m i s s t h e p o i n t that w h a t c o u n t s a s t h e b e s t e x p l a n a t i o n of s o m e p h e n o m e n o n is a l w a y s relative to o n e ' s b a c k g r o u n d b e l i e f s . It is t h e s e b e l i e f s that vary a c r o s s c u l t u r e s . T h e r e a s o n w h y t h e h y p o t h e s i s that a n illness w a s c a u s e d by t h e a c t i o n o f a w i t c h is n o t a g o o d e x p l a n a t i o n for u s is that w e d o n o t b e l i e v e i n w i t c h c r a f t . It is t h u s p l a u s i b l e that all c u l t u r e s e m p l o y t h e s a m e g e n e r a l s t a n d a r d s for s e l e c t i n g b e t w e e n c o m p e t i n g e x p l a n a t i o n s , g i v e n their b a c k g r o u n d b e l i e f s . N o t e that if i n f e r e n c e to t h e b e s t e x p l a n a t i o n is a g e n e r a l l y reliable m e t h o d of f o r m i n g b e l i e f s , t h e n it is e a s y t o e x p l a i n h o w o u r c o n c e p t of it c o u l d c o m e to b e i n n a t e . F o r i n d i v i d u a l s will b e b e t t e r a b l e to s u r v i v e if t h e y a r e able to attain t r u e b e l i e f s a b o u t

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t h e u n d e r l y i n g p r o c e s s e s at w o r k in n a t u r e , w h i c h c a n t h e n b e h a r n e s s e d a n d e x p l o i t e d , or if t h e y c a n a c q u i r e k n o w l e d g e of t h e u n s e e n c a u s e s of o b s e r v a b l e p h e n o m e n a . ( C o n v e r s e l y , if o u r c o n c e p t of b e s t e x p l a n a t i o n h a s a l r e a d y b e e n s h o w n to b e i n n a t e , t h e n this g i v e s u s g o o d r e a s o n to b e l i e v e that s u c h i n f e r e n c e s a r e g e n e r a l l y reliable. F o r a c o n c e p t c o u l d n o t h a v e b e e n s e l e c t e d t h r o u g h e v o l u t i o n if it did n o t c o n f e r survival v a l u e o n t h e i n d i v i d u a l s w h o p o s s e s s it. Y e t it is h a r d to s e e h o w i n f e r e n c e to t h e b e s t e x p l a n a t i o n c o u l d h a v e survival v a l u e , u n l e s s it is i n d e e d reliable. W e shall r e t u r n to this i s s u e in c h a p t e r 12.) I c o n c l u d e t h a t , w h i l e t h e c a s e for i n n a t e c o n c e p t s is largely u n p r o v e n , t h e r e is at least o n e c o n c e p t that is p r o b a b l y i n n a t e , n a m e l y o u r c o n c e p t of b e s t e x p l a n a t i o n . T h i s result will p r o v e to b e of s o m e i m p o r t a n c e in c h a p t e r s 11 a n d 12, w h e n w e c o m e to discuss the problem of scepticism.

8 The Case for Innate Knowledge IN this c h a p t e r I shall c o n s i d e r t h e m o s t likely c a n d i d a t e for s u b s t a n t i v e i n n a t e k n o w l e d g e , n a m e l y o u r beliefs a b o u t o u r own psychology.

I n n a t e n e s s a n d Reliability Recall f r o m c h a p t e r 5 that in o r d e r for t h e r e to b e i n n a t e k n o w l e d g e , w e m u s t p o s s e s s s o m e i n n a t e beliefs t h a t a r e n o t o n l y t r u e , b u t c a u s e d b y a reliable p r o c e s s . W h i l e classical rationalists h e l d that t h e p r o c e s s in q u e s t i o n w a s d i v i n e i n t e r v e n t i o n ( o u r i n n a t e b e l i e f s h a v i n g b e e n i m p l a n t e d in u s b y a v e r a c i o u s G o d ) , this idea is n o l o n g e r t a k e n s e r i o u s l y i n scientific c u l t u r e s . In o r d e r for a c l a i m to i n n a t e k n o w l e d g e to b e g i v e n e v e n c u r s o r y c o n s i d e r a t i o n t o d a y , t h e p r o p o s e d beliefc a u s i n g p r o c e s s m u s t be a natural o n e . I n d e e d , t h e o n l y s u g g e s t i o n t h a t is c o n s i s t e n t w i t h c u r r e n t scientific k n o w l e d g e is that i n n a t e b e l i e f s m i g h t b e d e t e r m i n e d t h r o u g h e v o l u t i o n a r y s e l e c t i o n . F o r s c i e n c e tells u s t h a t this is t h e m a n n e r in w h i c h all o t h e r i n n a t e c h a r a c t e r i s t i c s h a v e b e e n a r r i v e d at, w h e t h e r i n o u r s e l v e s o r in o t h e r o r g a n i s m s . W h a t r e a s o n is t h e r e for t h i n k i n g that n a t u r a l s e l e c t i o n w o u l d b e a reliable p r o c e s s , s u p p o s i n g that it r e s u l t e d in s o m e i n n a t e b e l i e f s ? N o t i c e , first, that t r u e belief h a s i m m e n s e survival v a l u e for a n y o r g a n i s m , s u c h as o u r s e l v e s , m u c h of w h o s e b e h a v i o u r is c a u s e d b y t h e i n t e r a c t i o n of b e l i e f s a n d d e s i r e s . F o r i n g e n e r a l a n o r g a n i s m ' s p r o j e c t s will o n l y s u c c e e d if b a s e d u p o n b e l i e f s that a r e true. T h i s is n o t to s a y , o f c o u r s e , t h a t a c t i o n u n d e r t a k e n o n t h e b a s i s of a true b e l i e f is g u a r a n t e e d t o s u c c e e d . I m a y set off w a l k i n g t h r o u g h t h e d e s e r t , correctly b e l i e v i n g t h a t t h e r e is

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w a t e r to b e f o u n d in that d i r e c t i o n , b u t p e r i s h of thirst b e f o r e I r e a c h it. B u t o f t e n ( t h o u g h n o t a l w a y s ) t h e failure will r e s u l t f r o m t h e falsity of s o m e o t h e r belief. T h u s , in this e x a m p l e , it m a y b e m y false belief that t h e w a t e r is c l o s e e n o u g h for m e to reach by w a l k i n g that is r e s p o n s i b l e for m y d e a t h . ( O n t h e o t h e r h a n d , I m a y s i m p l y h a v e l a c k e d a n y a l t e r n a t i v e c o u r s e of a c t i o n , so that I would have perished whatever I did.) It is a l s o true that action u n d e r t a k e n o n t h e b a s i s of a false belief is n o t g u a r a n t e e d to fail. O n e w a y in w h i c h t h e action m a y n e v e r t h e l e s s s u c c e e d is w h e r e t h e belief, w h i l e false, is sufficiently c l o s e to t h e truth. For e x a m p l e , a l t h o u g h m y belief a b o u t the direction of the o a s i s m a y b e strictly i n c o r r e c t , it m a y still lead m e to w i t h i n s i g h t i n g d i s t a n c e of t h e w a t e r I n e e d . If a n action b a s e d u p o n a w h o l l y false b e l i e f s u c c e e d s , h o w e v e r , it will o n l y s u c c e e d b y a c c i d e n t . For e x a m p l e , a l t h o u g h w a l k i n g in the w r o n g direction to find the o a s i s I a m a i m i n g for, I m a y b e lucky e n o u g h to s t u m b l e a c r o s s a n o t h e r , a n d h e n c e s u r v i v e a n y w a y . S o w h o l l y false beliefs will n o t h a v e survival v a l u e in the l o n g r u n , a n d in e v o l u t i o n a r y s e l e c t i o n it is the l o n g r u n that m a t t e r s . W h a t s e e m s u n d e n i a b l e is that o r g a n i s m s (of t h e sort that act o n beliefs) will o n l y s u r v i v e , in g e n e r a l a n d in t h e l o n g r u n , if t h e y b a s e their a c t i o n s on beliefs that a r e t r u e , or at least c l o s e to the truth. S o if a n y i n n a t e b e l i e f s h a v e a r i s e n t h r o u g h n a t u r a l s e l e c t i o n , w e s h o u l d e x p e c t t h e m to b e at least approximately true. A n o b j e c t i o n to this line of a r g u m e n t , h o w e v e r , is that n a t u r a l s e l e c t i o n c a n e x p l a i n f e a t u r e s of o r g a n i s m s that d o not h a v e survival v a l u e , p r o v i d e d that t h e y a r e b y - p r o d u c t s of t h i n g s that do h a v e it. If this w e r e t r u e of i n n a t e b e l i e f s , t h e r e w o u l d b e n o p a r t i c u l a r r e a s o n to e x p e c t t h e b e l i e f s in q u e s t i o n to b e true o n e s . ( I n d e e d , e v e n if t h o s e beliefs did h a p p e n to b e true t h e y w o u l d n o t c o u n t as reliably a c q u i r e d , a n d h e n c e w o u l d n o t b e k n o w n . F o r their t r u t h w o u l d t h e n t u r n out to b e a c c i d e n t a l relative to t h e p r o c e s s e s i n v o l v e d in their a c q u i s i t i o n . ) Y e t this o b j e c t i o n c a n n o t b e s u s t a i n e d , at l e a s t in t h e a b s e n c e of a n y c o n c r e t e p r o p o s a l . F o r it is e x t r e m e l y difficult to u n d e r s t a n d h o w i n n a t e beliefs m i g h t b e a b y - p r o d u c t of s o m e o t h e r i n n a t e c h a r a c t e r i s t i c of h u m a n b e i n g s , w i t h o u t t h e m s e l v e s h a v i n g a v a l u e in survival c o n t i n g e n t u p o n their t r u t h . A n o t h e r p o i n t to n o t i c e is that n a t u r a l s e l e c t i o n h a s c o n f e r r e d on u s b e l i e f - a c q u i s i t i o n p r o c e s s e s t h a t a r e g e n e r a l l y reliable.

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Beliefs a r i s i n g f r o m p e r c e p t i o n a n d m e m o r y a r e , o n t h e w h o l e , t r u e . ( T h o s e sceptical of this will b e a n s w e r e d in c h a p t e r s 11 a n d 12.) S o e v e n if e v o l u t i o n d o e s n o t i s s u e directly in a n y b e l i e f s , it h a s r e s u l t e d in i n n a t e m e c h a n i s m s for a c q u i r i n g b e l i e f s that are fairly reliable. It is t h e r e f o r e , to that e x t e n t , a reliable p r o c e s s in its t u r n . M o r e o v e r p a r t , at least, of t h e i n a c c u r a c y of o u r p e r c e p t u a l m e c h a n i s m s c a n b e a c c o u n t e d for in t e r m s of a c o m p e t i n g c o n s t r a i n t , w h i c h w o u l d n o t o p e r a t e (or n o t t o t h e s a m e e x t e n t ) in t h e c a s e of i n n a t e b e l i e f s . T h i s is s p e e d . P e r c e p t u a l m e c h a n i s m s n e e d to b e fast a s well as reliable. S o t h e r e m a y b e survival v a l u e for a n o r g a n i s m in s o m e sacrifice of reliability, if this is m o r e t h a n offset b y a c o r r e s p o n d i n g gain in s p e e d . F o r e x a m p l e , it will b e a n a d v a n t a g e to h a v e a p e r c e p t u a l m e c h a n i s m that i n f o r m s m e e x t r e m e l y quickly that t h e r e is a p r e d a t o r r u n n i n g t o w a r d s m e , e v e n i f — a s a r e s u l t of t h e s p e e d w i t h w h i c h it o p e r a t e s — t h e m e c h a n i s m o f t e n i n f o r m s m e that t h e r e is a p r e d a t o r a p p r o a c h i n g w h e n t h e r e is n o t . B e t t e r s o m e t i m e s to flee u n n e c e s s a r i l y t h a n n e v e r to h a v e t i m e to flee at all! But in c o n n e c t i o n with i n n a t e b e l i e f s , a s o p p o s e d to p e r c e p t u a l m e c h a n i s m s , t h e r e is p r e s u m a b l y n o d e m a n d for s p e e d ( e x c e p t p e r h a p s s p e e d in a c c e s s i n g a n d c a l c u l a t i n g w i t h t h o s e b e l i e f s ) . S o e v o l u t i o n a r y s e l e c t i o n of i n n a t e b e l i e f s w o u l d , if a n y t h i n g , b e e v e n more reliable t h a n that of p e r c e p t u a l mechanisms. It is p o s s i b l e to i m a g i n e c a s e s w h e r e an i n n a t e false belief w o u l d b e a n aid to survival. F o r e x a m p l e , a n i n n a t e b e l i e f in the m a g i c a l p r o p e r t i e s of a p a r t i c u l a r p l a n t , w h i c h in fact c o n t a i n s a p o w e r f u l m e d i c i n e , m i g h t p r o v e v e r y u s e f u l to t h o s e w h o live in t h e r e g i o n w h e r e t h a t p l a n t f l o u r i s h e s . B u t s u c h c a s e s are r e n d e r e d u n l i k e l y w h e n o n e r e m e m b e r s that in o r d e r to h a v e b e e n s e l e c t e d t h r o u g h e v o l u t i o n , a belief w o u l d h a v e to p r o v e u s e f u l o v e r a t i m e - s p a n that is e x t r e m e l y l o n g in c o m p a r i s o n to h u m a n h i s t o r y , a n d in a w i d e v a r i e t y of differing c i r c u m s t a n c e s . I t h e r e f o r e c o n c l u d e that if e v o l u t i o n h a s r e s u l t e d in a n y i n n a t e b e l i e f s , t h e n t h o s e b e l i e f s will v e r y likely c o n s t i t u t e i n n a t e knowledge. Recall that in c h a p t e r 6 w e d i s c o v e r e d s o m e c a n d i d a t e s for i n n a t e k n o w l e d g e , in t h e c o u r s e of o u r d i s c u s s i o n of i n n a t e mental structure. T h u s , while we disagreed with C h o m s k y ' s claim t h a t t h e i n n a t e s t r u c t u r e of t h e l a n g u a g e faculty s h o u l d b e c o u n t e d a s g e n u i n e k n o w l e d g e , w e n o t e d that o u r c o n s c i o u s

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b e l i e f s a b o u t w h e t h e r a particular s e n t e n c e is or is n o t w e l l f o r m e d will c o u n t as i n n a t e l y k n o w n . F o r s u c h b e l i e f s a r e t r u e , a n d a r e c a u s e d b y a reliable p r o c e s s , p r o v i d e d that t h e y r e s u l t in a s y s t e m a t i c w a y f r o m t h e u n d e r l y i n g s t r u c t u r e of t h e l a n g u a g e faculty. B u t if this is t h e total e x t e n t of o u r i n n a t e k n o w l e d g e , it will b e of very m a r g i n a l s i g n i f i c a n c e . F o r it is n o t t h e s e beliefs t h e m s e l v e s that e x p l a i n o u r c a p a c i t y to f o r m u l a t e a n d to r e c o g n i z e g r a m m a t i c a l s e n t e n c e s . T h e y r a t h e r arise o u t of w h a t d o e s e x p l a i n that c a p a c i t y , n a m e l y t h e i n n a t e s t r u c t u r e of t h e l a n g u a g e faculty, t o g e t h e r with t h e s u b j e c t ' s p a r a m e t e r - s e t t i n g e x p e r i e n c e of their n a t i v e l a n g u a g e . I n d e e d , it is a r g u a b l e that t h e v e r y idea of a s e n t e n c e b e i n g well f o r m e d or ill f o r m e d o n l y a r i s e s in c u l t u r e s w h e r e for political r e a s o n s a t t e m p t s a r e m a d e to s t a n d a r d i z e d i f f e r e n t dialects. I a m t o l d , for e x a m p l e , that l i n g u i s t s w o r k i n g in t h e field o f t e n h a v e c o n s i d e r a b l e difficulty in e x p l a i n i n g to t h e m e m b e r s of t h e l a n g u a g e c o m m u n i t y t h e y are s t u d y i n g just w h a t it is t h e y are a f t e r w h e n t h e y s e e k t h e s p e a k e r s ' j u d g e m e n t s as to w h e t h e r or n o t a g i v e n n a t i v e s e n t e n c e is well f o r m e d . In c h a p t e r 6 w e also a l l o w e d that o t h e r faculties, s u c h a s vision, are innately structured, e m b o d y i n g information about the w o r l d . If this is s o , t h e n it s e e m s t h a t p e r c e p t u a l b e l i e f s will (somewhat strangely) count as innate, being triggered by e x p e r i e n c e r a t h e r t h a n l e a r n e d f r o m it. B u t p e r h a p s a b e t t e r w a y to p u t t h e p o i n t is t h i s . T h e i n n a t e s t r u c t u r e of t h e visual faculty m a y g i v e u s i n n a t e (locally t r i g g e r e d ) k n o w l e d g e that t h e r e a r e , in g e n e r a l , p h y s i c a l o b j e c t s d i s t r i b u t e d in t h r e e - d i m e n s i o n a l space around us. But then our particular perceptual beliefs—for e x a m p l e , that t h e r e is a cylindrical o b j e c t r e s t i n g o n a flat s u r f a c e in f r o n t of m e n o w — a r e b a s e d u p o n e x p e r i e n c e . F o r it is o n l y o u r g e n e r a l ability to p e r c e i v e in t h r e e d i m e n s i o n s that is u n l e a r n e d . O n that b a s i s w e t h e n learn w h e r e p a r t i c u l a r o b j e c t s are b y s e e i n g . S o o u r d e t a i l e d p e r c e p t u a l k n o w l e d g e of t h e world around us should not be counted as innate. If w e are to s h o w that w e h a v e i n n a t e s u b s t a n t i v e k n o w l e d g e of d e t a i l e d t r u t h s a b o u t t h e w o r l d , w e n e e d to c o n s i d e r s o m e other candidates. O n e example m a y be provided by our k n o w l e d g e of o u r o w n p s y c h o l o g y .

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Folk-Psychology W e h a v e a n i m m e n s e n e t w o r k of c o m m o n - s e n s e b e l i e f s a b o u t t h e m i n d . T h e s e b e l i e f s c o n c e r n t h e r e l a t i o n s h i p s of m e n t a l states to o n e a n o t h e r , to t h e e n v i r o n m e n t a n d s t a t e s of t h e b o d y , a n d to b e h a v i o u r . T h i s c o l l e c t i o n of b e l i e f s is g e n e r a l l y r e f e r r e d to b y p h i l o s o p h e r s t o d a y a s ' f o l k - p s y c h o l o g y ' . It i n c l u d e s s u c h beliefs as t h e s e : that p a i n s t e n d t o b e c a u s e d b y i n j u r y , a n d t e n d to p r e v e n t y o u f r o m c o n c e n t r a t i n g u p o n o t h e r t a s k s ; that p e r c e p t i o n s a r e g e n e r a l l y c a u s e d b y t h e a p p r o p r i a t e state o f t h e e n v i r o n m e n t (for e x a m p l e , t h e e x p e r i e n c e of a tiger b e i n g c a u s e d b y t h e p r e s e n c e of a tiger), a n d a r e o f t e n laid d o w n in m e m o r y ; t h a t if y o u w a n t s o m e t h i n g , a n d b e l i e v e that p e r f o r m i n g a n a c t i o n or s e q u e n c e of a c t i o n s will e n a b l e y o u to g e t it, t h e n y o u will n o r m a l l y ( o t h e r t h i n g s b e i n g e q u a l ) d o that t h i n g ; that d e c i s i o n s a r e o f t e n t h e result of prior d e l i b e r a t i o n , a n d g e n e r a l l y l e a d y o u to p e r f o r m t h e a c t i o n d e c i d e d u p o n ; that w h e n y o u a s s e r t s o m e t h i n g , y o u g e n e r a l l y b e l i e v e it, a n d w h e n y o u s a y y o u are g o i n g to d o s o m e t h i n g , y o u g e n e r a l l y d o it; a n d so on. It is i m p o r t a n t to s t r e s s that f o l k - p s y c h o l o g y s h o u l d o n l y b e u n d e r s t o o d to c o v e r t h e set of c o m m o n - s e n s e g e n e r a l i z a t i o n s a b o u t t h e h u m a n m i n d that h o l d g o o d i n d e p e n d e n t l y o f c o n t e x t or c u l t u r e . F o r it is p e r f e c t l y o b v i o u s t h a t o u r particular b e l i e f s a b o u t s o m e o n e ' s p s y c h o l o g y — c o n c e r n i n g their i n d i v i d u a l d e s i r e s , i n t e n t i o n s , a n d b e l i e f s — w i l l n o t b e i n n a t e , b u t will r a t h e r b e l e a r n e d f r o m o b s e r v a t i o n of their b e h a v i o u r . S i m i l a r l y , w h e n w e arrive for t h e first t i m e in a f o r e i g n c o u n t r y w e m a y n o t b e able to t a k e m u c h for g r a n t e d a b o u t t h e i r c u s t o m s , o r a b o u t w h a t t h e y b e l i e v e or v a l u e . S o w e shall n o t b e a b l e to rely u p o n s u c h c u l t u r e - r e l a t i v e g e n e r a l i z a t i o n s a s t h a t a h a n d - s h a k e will b e t r e a t e d as a sign of g r e e t i n g . B u t w h a t w e can t a k e for g r a n t e d is that t h e g e n e r a l w a y in w h i c h their m i n d s w o r k will b e similar t o o u r s — f o r e x a m p l e , t h a t t h e y will g e n e r a l l y b e l i e v e w h a t t h e y s e e . A n d it is this g e n e r a l k n o w l e d g e t h a t w e shall l a r g e l y rely o n in i n t e r p r e t i n g their b e h a v i o u r , a n d i n b e g i n n i n g to c o n s t r u c t d e t a i l e d p i c t u r e s of their p s y c h o l o g y . T h e r e a r e a n u m b e r o f p o i n t s to n o t i c e a b o u t f o l k - p s y c h o l o g y . T h e first is that it is e x t r e m e l y c o m p l e x , c o n s i s t i n g of p e r h a p s m a n y t h o u s a n d s of d i s t i n c t g e n e r a l i z a t i o n s . T h i s c o m p l e x i t y c a n

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easily p a s s u n n o t i c e d , s i n c e w e a r e s o at h o m e w i t h i n folkp s y c h o l o g y that w e a r e b a r e l y a w a r e of its e x i s t e n c e . B u t t h e c o m p l e x i t y e m e r g e s as s o o n as w e try to articulate e v e r y t h i n g that c o m m o n - s e n s e tells u s a b o u t t h e m i n d . ( T o s e e t h i s , j u s t try completing t h e list of g e n e r a l i z a t i o n s s t a r t e d in t h e p a r a g r a p h b e f o r e last!) W e m i g h t b e t e m p t e d to say that f o l k - p s y c h o l o g y is n o l e s s c o m p l i c a t e d t h a n t h e h u m a n m i n d itself. B u t this w o u l d b e a n e x a g g e r a t i o n . F o r a g r e a t d e a l of t h e o p e r a t i o n of o u r m i n d s i s , n o d o u b t , n o n - c o n s c i o u s ; w h e r e a s f o l k - p s y c h o l o g y is m o s t l y c o n c e r n e d with o u r c o n s c i o u s m e n t a l life. But e v e n this is c o m p l i c a t e d e n o u g h . T h e s e c o n d p o i n t to n o t i c e a b o u t f o l k - p s y c h o l o g y is that, w h i l e it m a y b e l o o s e l y s t r u c t u r e d a n d i m p r e c i s e , it is also r e m a r k a b l y s u c c e s s f u l . ' B e c a u s e of it, the a c t i o n s of o t h e r p e o p l e as well a s o u r s e l v e s a r e o f t e n p r e d i c t a b l e , a n d a l m o s t a l w a y s intelligible. ( W e c a n m a k e s e n s e of o n e a n o t h e r , in a w a y that w e a r e a b l e to u n d e r s t a n d h a r d l y a n y t h i n g else in t h e natural w o r l d . ) I n d e e d , it is o n l y b e c a u s e of f o l k - p s y c h o l o g y that social life is p o s s i b l e at all. W e c o n s t a n t l y rely u p o n it in i n t e r p r e t i n g t h e u t t e r a n c e s of o t h e r p e o p l e ; in r e c o v e r i n g f r o m their u t t e r a n c e s , c i r c u m s t a n c e s , a n d b e h a v i o u r a d e s c r i p t i o n of their b e l i e f s a n d i n t e n t i o n s ; in p r e d i c t i n g w h a t m a y b e e x p e c t e d of p e o p l e with t h o s e b e l i e f s a n d i n t e n t i o n s in a g i v e n s i t u a t i o n ; a n d in p r e d i c t i n g t h e e f f e c t s o n o t h e r p e o p l e of o u r o w n u t t e r a n c e s a n d a c t i o n s . T o s e e h o w s u c c e s s f u l w e are in all t h i s , reflect u p o n t h e c o m p l e x i t y a n d diversity of m o d e r n s o c i e t i e s , a n d yet o n t h e e x t e n t to w h i c h w e n e v e r t h e l e s s m a n a g e to c o - o r d i n a t e our behaviour. J u s t a s it is e a s y to o v e r l o o k t h e c o m p l e x i t y o f folkp s y c h o l o g y , s o it is e a s y to u n d e r e s t i m a t e its s u c c e s s . F o r o u r o c c a s i o n a l m u d d l e s a n d m i s u n d e r s t a n d i n g s t e n d to h a v e far g r e a t e r s a l i e n c e for u s . T h i s is b e c a u s e m a n y of t h e c a s e s that m a t t e r to u s m o s t a r e t h o s e w h e r e u n d e r s t a n d i n g is h a r d e s t to c o m e b y . T h u s o n e p e r s o n ' s r e l i g i o u s , m o r a l , or political b e l i e f s m a y s e e m c o m p l e t e l y m y s t e r i o u s to a n o t h e r . I n d e e d , b y generalizing from and romanticizing such cases, some people are i n c l i n e d to p i c t u r e h u m a n b e i n g s a s w h o l l y o p a q u e to o n e a n o t h e r , b e y o n d m u t u a l k n o w l e d g e or c o m p r e h e n s i o n . W h a t 1

T h i s p o i n t is m a d e c o n v i n c i n g l y b y J e r r y F o d o r , Psychosemantics

M a s s . : M I T P r e s s ) , c h . 1, a s a r e m a n y o f t h e p o i n t s t h a t f o l l o w .

(Cambridge,

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t h e y o v e r l o o k a r e t h e m y r i a d c a s e s of m u n d a n e s u c c e s s . E v e n t h o s e w i t h w i d e l y d i f f e r i n g r e l i g i o u s beliefs c a n c o - o p e r a t e s u c c e s s f u l l y in practical p r o j e c t s , s u c h a s b u i l d i n g a wall t o g e t h e r , or c o - o r d i n a t i n g a m e e t i n g in a s t r a n g e city. A n d m a n y of their e v e r y d a y a c t i o n s will b e m u t u a l l y intelligible. T h e third p o i n t to n o t i c e a b o u t f o l k - p s y c h o l o g y , b e s i d e s its c o m p l e x i t y a n d r e m a r k a b l e s u c c e s s , is that it is a l s o deep. As a first a p p r o x i m a t i o n , y o u m i g h t say that this d e p t h c o n s i s t s in the fact that f o l k - p s y c h o l o g y e x p l a i n s a n d p r e d i c t s h u m a n b e h a v i o u r t h r o u g h t h e interaction of unobservables—beliefs, d e s i r e s , f e e l i n g s , a n d t h o u g h t s . In this r e s p e c t , at least, it m i g h t b e c o m p a r e d to h i g h l y d e v e l o p e d s c i e n c e s s u c h a s p h y s i c s a n d c h e m i s t r y , w h i c h similarly e x p l a i n t h e o b s e r v a b l e b e h a v i o u r of p h y s i c a l s u b s t a n c e s in t e r m s of t h e u n o b s e r v a b l e i n t e r a c t i o n s o f their p a r t s . H o w e v e r , this w a y of p u t t i n g the p o i n t p r e s u p p o s e s a d i s t i n c t i o n b e t w e e n t h e o r y a n d o b s e r v a t i o n that is h i g h l y c o n t e n t i o u s . M a n y p h i l o s o p h e r s w o u l d w a n t to insist, on t h e c o n t r a r y , that w e can literally see s o m e o n e ' s pain or d e s i r e , a g a i n s t t h e b a c k g r o u n d of o u r b e l i e f s a b o u t their c i r c u m s t a n c e s a n d o t h e r m e n t a l s t a t e s . S i m i l a r l y , m a n y p h i l o s o p h e r s of s c i e n c e w o u l d w a n t to s a y that a p h y s i c i s t in t h e c o u r s e o f a n e x p e r i m e n t m a y — i n t h e light of their b a c k g r o u n d t h e o r e t i c a l b e l i e f s — b e said to see e l e c t r o n s b e i n g d i s c h a r g e d from t h e substance under study. These philosophers would maintain t h a t , s i n c e w h a t w e s e e is a l w a y s to s o m e e x t e n t a f u n c t i o n of w h a t w e b e l i e v e , t h e r e is n o m o t i v e for d e n y i n g that e n t i t i e s s u c h as p a i n s a n d e l e c t r o n s are o b s e r v a b l e . A b e t t e r w a y to c h a r a c t e r i s e t h e d e p t h o f f o l k - p s y c h o l o g y is to s t r e s s its implicit realism. It c o m m i t s u s to t h e real e x i s t e n c e of m e n t a l s t a t e s a n d e v e n t s , a n d real c a u s a l i n t e r a c t i o n s b e t w e e n t h e m . I n d e e d , it e m b o d i e s a c o m p l e x t h e o r y a b o u t t h e i n n e r s t r u c t u r e of t h e m i n d . C o n s i d e r , for e x a m p l e , a f o l k - p s y c h o logical e x p l a n a t i o n of s o m e o n e ' s d e c i s i o n in t e r m s of t h e train of r e a s o n i n g that led u p to it. T h i s p o s t u l a t e s a c a u s a l s e q u e n c e of real e v e n t s , w h i c h w e r e u n o b s e r v a b l e in fact, e v e n if n o t in principle. O n e q u e s t i o n left o u t s t a n d i n g is to w h a t e x t e n t t h e g e n e r a l i z a t i o n s of f o l k - p s y c h o l o g y a r e c o n s c i o u s l y b e l i e v e d . It m i g h t b e s u g g e s t e d t h a t t h e y s h o u l d r a t h e r b e a s s i m i l a t e d to t h e sort of n o n - c o n s c i o u s m e n t a l s t r u c t u r e s t h a t u n d e r l i e o u r g r a s p of

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g r a m m a t i c a l r u l e s . N o w it m a y b e that t h e r e a r e s u c h s t r u c t u r e s h e r e t o o , b u t it is s u r e l y u n d e n i a b l e that g e n e r a l i z a t i o n s of t h e sort m e n t i o n e d earlier will b e c o n s c i o u s l y e n d o r s e d . T h i s n e e d n o t m e a n that t h e y o f t e n (or in fact e v e r ) surface in c o n s c i o u s n e s s . F o r b e i n g truistic (too o b v i o u s to m e n t i o n ) , t h e y m o s t l y p a s s u n t h o u g h t of. B u t t h e y a r e c e r t a i n l y available to c o n s c i o u s n e s s , s i n c e s p e a k e r s will i m m e d i a t e l y a s s e n t to t h e m if a s k e d . T h i s is n o t to s a y , h o w e v e r , that w e c a n n o t m a k e m i s t a k e s w h e n w e try t o articulate the p r i n c i p l e s w e a r e t a k i n g for g r a n t e d . For e x a m p l e , at o n e p o i n t F o d o r s a y s that p e o p l e will ( o t h e r t h i n g s b e i n g e q u a l ) d o w h a t e v e r t h e y b e l i e v e to b e necessary to fulfil their d e s i r e s . B u t this is false if t a k e n q u i t e g e n e r a l l y . W h a t really m a t t e r s is that t h e act b e sufficient, or b e p a r t of a s e q u e n c e of a c t i o n s that is b e l i e v e d t o b e s u f f i c i e n t . T h u s e v e n if I w o u l d like to b e c o m e a f a m o u s c o n c e r t p i a n i s t , a n d b e l i e v e that it is n e c e s s a r y that 1 s h o u l d first l e a r n to p l a y t h e p i a n o , it d o e s n o t follow that I will m a k e t h e a t t e m p t . F o r I m i g h t a l s o b e l i e v e t h a t e v e n if I l e a r n e d t h e p i a n o I s h o u l d n e v e r b e g o o d e n o u g h to b e f a m o u s . 2

Is Folk-Psychology L e a r n e d ? F o l k - p s y c h o l o g y is a p p a r e n t l y u n i v e r s a l to all h u m a n c o m m u n ities. S o far a s I a m a w a r e , t h e r e are n o s o c i e t i e s that fail to h a v e n o t i o n s c o r r e s p o n d i n g to t h o s e of p a i n a n d a n g e r , a n d that d o n o t e m p l o y t h e p r a c t i c a l - r e a s o n i n g - m o d e l for e x p l a i n i n g a c t i o n s in t e r m s of t h e i n t e r a c t i o n of beliefs a n d d e s i r e s . T h i s is, if t r u e , a striking fact. T h e r e is h a r d l y a n y o t h e r c o m p a r a b l e b o d y of beliefs t h a t is e q u a l l y u n i v e r s a l . I n d e e d , t h e o n l y real c a n d i d a t e is f o l k - p h y s i c s , w h i c h i n c l u d e s s u c h t r u i s m s as that it t a k e s m o r e e n e r g y to lift a h e a v y o b j e c t t h a n a light o n e . A c a s e c a n b e m a d e for s a y i n g that t h i s , t o o , is i n n a t e . B u t I shall n o t p u r s u e t h e matter here. S t e p h e n Stich h a s r a i s e d d o u b t s a b o u t t h e u n i v e r s a l i t y of folkp s y c h o l o g y , citing t h e w o r k of t h e a n t h r o p o l o g i s t R o d n e y 3

S e e Psychosemantics, 2. S e e From Folk Psychology 1983), 2 1 7 - 1 9 . 2

3

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N e e d h a m . B u t in reality t h e a n t h r o p o l o g i c a l e v i d e n c e p r e s e n t e d b y N e e d h a m supports t h e u n i v e r s a l i t y of f o l k - p s y c h o l o g y . W h a t s e e m s to c o u n t a g a i n s t it is o n l y a faulty ( W i t t g e n s t e i n i a n ) a n a l y s i s of f o l k - p s y c h o l o g i c a l n o t i o n s . O n s u c h a n a c c o u n t , t h e s e n o t i o n s are c o n c e p t u a l l y tied to specific t y p e s of b e h a v i o u r a l criteria, a n d a r e n e c e s s a r i l y e m b e d d e d in p a r t i c u l a r linguistic a n d cultural p r a c t i c e s . In w h i c h c a s e , s i n c e in m a n y s o c i e t i e s t h e s e p r a c t i c e s are a b s e n t , t h e n o t i o n of belief, for e x a m p l e , m a y b e h e l d to b e w i t h o u t a p p l i c a t i o n . But in fact, as w e h a v e s e e n , f o l k - p s y c h o l o g y p o s t u l a t e s a n e t w o r k of c a u s a l l y r e l a t e d real i n t e r n a l s t a t e s a n d e v e n t s , w h e r e s u c h s t a t e s will o n l y i s s u e in a g i v e n t y p e of b e h a v i o u r if o t h e r t h i n g s a r e e q u a l — t h a t is, if t h e s u r r o u n d i n g s t a t e s in t h e n e t w o r k r e m a i n t h e s a m e . F r o m this p e r s p e c t i v e , it is only to be e x p e c t e d that p e o p l e in d i f f e r e n t c u l t u r e s , w h i l e e n j o y i n g t h e s a m e types of m e n t a l state ( b e l i e f s , d e s i r e s , a n d s o o n ) , m i g h t e n g a g e in v e r y d i f f e r e n t b e h a v i o u r s , d e p e n d i n g u p o n t h e particular b e l i e f s a n d v a l u e s that a r e c u r r e n t a m o n g s t their m e m b e r s . 4

5

H o w e v e r , t h e u n i v e r s a l i t y of f o l k - p s y c h o l o g y is n o t in itself sufficient to s h o w that f o l k - p s y c h o l o g i c a l beliefs are i n n a t e . F o r s u p p o s i n g t h a t t h o s e b e l i e f s a r e largely t r u e , t h e n it is clear that n o h u m a n s o c i e t y w o u l d last v e r y l o n g w i t h o u t t h e m . S i n c e a s h a r e d c o m m o n - s e n s e p s y c h o l o g y is t h e b a s i s o n w h i c h all social c o - o p e r a t i o n a n d c o m m u n i c a t i o n rest, g r o u p s o f h u m a n s w h o did n o t p o s s e s s it w o u l d b e h a r d p u t to s u r v i v e , let a l o n e flourish. B u t , for all t h a t , it m a y b e that the beliefs in q u e s t i o n a r e e m p i r i c a l l y a c q u i r e d . It m a y b e that t h e y w e r e g r a d u a l l y d i s c o v e r e d b y e m e r g i n g l y s u c c e s s f u l social g r o u p s in the p a s t , a n d a r e n o w p a s s e d o n b e t w e e n g e n e r a t i o n s b y t e a c h i n g . O r it m a y b e t h a t t h e y are r e d i s c o v e r e d b y e a c h i n d i v i d u a l in t h e c o u r s e of n o r m a l p s y c h o l o g i c a l d e v e l o p m e n t . In fact, h o w e v e r (as in t h e c a s e s of g r a m m a t i c a l r u l e s a n d c o n c e p t s ) , v e r y little, if a n y , explicit t e a c h i n g of f o l k - p s y c h o l o g y t a k e s p l a c e . A d u l t s s i m p l y use p s y c h o l o g i c a l n o t i o n s in t h e p r e s e n c e of c h i l d r e n , l e a v i n g t h e latter to a c q u i r e b y t h e m s e l v e s t h e g e n e r a l i z a t i o n s w i t h i n w h i c h t h o s e n o t i o n s are e m b e d d e d . I n d e e d , P l a t o ' s P r o b l e m a r i s e s h e r e i n particularly stark f o r m . E s p . his b o o k Belief, Language and Experience ( O x f o r d : B l a c k w e l l , 1 9 7 2 ) . S e e L u d w i g W i t t g e n s t e i n , Philosophical Investigations (Oxford: Blackwell, 1953). 4

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F o r t h e b o d y of k n o w l e d g e that t h e child h a s to a c q u i r e is n o t o n l y l a r g e , b u t s t r u c t u r e d in a v e r y c o m p l e x w a y . S i n c e a l m o s t e v e r y m e n t a l state c a n interact w i t h a n y o t h e r , f o l k - p s y c h o l o g y m u s t c o n s i s t of literally t h o u s a n d s of g e n e r a l i z a t i o n s . Y e t r e c e n t e v i d e n c e s u g g e s t s that c h i l d r e n h a v e an a d e q u a t e m a s t e r y of a g r e a t deal of it, at least, by t h e e n d of their f o u r t h y e a r . ( I n d e e d , s i n c e m u c h of t h e e v i d e n c e r e l a t e s to t h e c h i l d ' s verbal ability, t h e actual time of a c q u i s i t i o n m a y b e earlier still. F o r it is o f t e n the c a s e that u n d e r s t a n d i n g p r e c e d e s t h e ability to a r t i c u l a t e . ) 6

M o r e o v e r , w h i l e t h e data available to t h e child m a y n o t actually b e c o r r u p t , it is certainly f r a g m e n t a r y a n d i n c o m p l e t e . S i n c e m u c h of f o l k - p s y c h o l o g y is truistic (to a d u l t s ) , it will h a r d l y e v e r be cited explicitly in e x p l a n a t i o n s . N o a d u l t e v e r s a y s t h i n g s like ' D a d d y h a s g o n e to t h e s h o p s b e c a u s e h e w a n t s food to eat t o n i g h t , b e l i e v e s that t h e r e is n o t h i n g s u i t a b l e in t h e h o u s e , b e l i e v e s that t h e s h o p s are t h e b e s t p l a c e to get f o o d , b e l i e v e s that n o w is a s u i t a b l e t i m e to g o to the s h o p s ' a n d s o o n . O n e s i m p l y s a y s ' D a d d y h a s g o n e s h o p p i n g to g e t s u p p e r ' . N o t e v e n t h e e n d l e s s ' W h y ? ' q u e s t i o n s of a 2-year-old will lead o n e to articulate a g e n e r a l i z a t i o n like ' W h e n p e o p l e w a n t s o m e t h i n g , a n d b e l i e v e that t h e y c a n d o s o m e t h i n g to get it, t h e y t e n d ( o t h e r t h i n g s b e i n g e q u a l ) to d o that t h i n g ' . S o h o w are w e s u p p o s e d to i m a g i n e that the child c a n g a t h e r , p u r e l y b y i n f e r e n c e f r o m its o w n o b s e r v a t i o n s , t h e full r e p e r t o i r e of p s y c h o l o g i c a l g e n e r a l i z a t i o n s ? M o r e o v e r , m u c h of w h a t is n e e d e d to f o r m u l a t e t h e s e g e n e r a l i z a t i o n s is in a n y c a s e h i d d e n f r o m t h e c h i l d . F o r , b e i n g i n n e r , it is n o t available to p r e theoretical observation. It m i g h t b e s u g g e s t e d that t h e child c a n l e a r n f o l k - p s y c h o logical g e n e r a l i z a t i o n s f r o m its o w n c a s e , by i n t r o s p e c t i o n . B u t this is h i g h l y i m p l a u s i b l e , for at l e a s t t w o r e a s o n s . T h e first is that e v e n if w e s u p p o s e that all m e n t a l s t a t e s a r e t r a n s p a r e n t l y available to c o n s c i o u s n e s s , as C a r t e s i a n m o d e l s of t h e m i n d maintain, the relevant causal connections are not. So w e would h a v e to s u p p o s e t h a t t h e y o u n g child h a s t h e ability to c o n s t r u c t (albeit n o n - c o n s c i o u s l y ) a n e x p l a n a t o r y t h e o r y of r e m a r k a b l e s o p h i s t i c a t i o n a n d c o m p l e x i t y . It w o u l d also b e v e r y s u r p r i s i n g t h a t all c h i l d r e n s h o u l d h a p p e n to hit u p o n t h e same t h e o r y . B u t 6

S e e e . g . H e n r y W e l l m a n , The Child's

MIT Press, 1990).

Theory

of the Mind

(Cambridge, Mass.:

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t h e s e c o n d r e a s o n w h y i n t r o s p e c t i o n c a n n o t b e t h e s o u r c e of the child's k n o w l e d g e of f o l k - p s y c h o l o g y is s i m p l e a n d d e v a s t a t i n g . It is that m a n y m e n t a l s t a t e s are n o t in a n y c a s e i m m e d i a t e l y available to i n t r o s p e c t i o n . W h i l e it is true that m a n y m e n t a l s t a t e s characteristically g i v e rise to a belief in their o w n e x i s t e n c e , that t h e y d o s o is itself o n e of t h e g e n e r a l i z a t i o n s of f o l k - p s y c h o l o g y that t h e child n e e d s to l e a r n . I n t r o s p e c t i o n c a n n o t , for e x a m p l e , s h o w y o u that y o u w e n t to t h e s h o p s b e c a u s e y o u w a n t e d to b u y f o o d a n d b e l i e v e d that it w a s a suitable t i m e to g o , if y o u r belief in t h e suitability of t h e t i m e d i d not s u r f a c e in a c o n s c i o u s t h o u g h t prior to y o u r a c t i o n . Y o u m a y n o w , l o o k i n g b a c k , s a y that of c o u r s e y o u h a d s u c h a b e l i e f u n d e r l y i n g w h a t y o u d i d ; b u t t h e n it c a n n o t b e i n t r o s p e c t i o n that tells y o u that s u c h r e t r o s p e c t i v e e x p l a n a t i o n is reliable. I c o n c l u d e that P l a t o ' s P r o b l e m c o n c e r n i n g t h e c h i l d ' s a c q u i s i tion of p s y c h o l o g i c a l g e n e r a l i z a t i o n s c a n n o t b e s o l v e d , u n l e s s w e s u p p o s e that m u c h of f o l k - p s y c h o l o g y is a l r e a d y i n n a t e , t r i g g e r e d locally b y t h e c h i l d ' s e x p e r i e n c e of itself a n d o t h e r s , rather than learned. S u p p o s i n g that t h e g e n e r a l i z a t i o n s of f o l k - p s y c h o l o g y a r e largely true (or at least c l o s e e n o u g h to t h e truth to b e s u c c e s s f u l ) , w e c a n c o n s t r u c t a n a d d i t i o n a l a r g u m e n t for s u p p o s i n g t h e m to b e i n n a t e . For their i n n a t e n e s s w o u l d c o n f e r c o n s i d e r a b l e a d v a n t a g e s in survival. Recall that it is o u r s h a r e d belief in f o l k - p s y c h o l o g y that m a k e s c o - o p e r a t i o n a n d c o m m u n i c a t i o n p o s s i b l e . S o if f o l k - p s y c h o l o g y h a d to b e l e a r n e d , it w o u l d h a v e to b e l e a r n e d first. N o c o - o p e r a t i o n c o u l d t a k e p l a c e between parents and children, and no other information could b e a c q u i r e d b y c h i l d r e n f r o m their p a r e n t s , until t h e r e l e v a n t generalizations h a d b e e n learned, and learned correctly. This w o u l d w a s t e t i m e a n d c o g n i t i v e r e s o u r c e s , at a s t a g e in d e v e l o p m e n t w h e n e v e r y a d d i t i o n a l fact that a child c a n l e a r n f r o m a d u l t s c a n s a v e its life. ( ' D o n ' t p l a y w i t h s n a k e s ; if y o u s e e a tiger, t h e n r u n ; d o n ' t try t o c l i m b i n t o t h e c o o k i n g p o t ' , a n d s o o n . ) O n t h e o t h e r h a n d , if t h e r e l e v a n t g e n e r a l i z a t i o n s a r e i n n a t e , o n l y n e e d i n g to b e t r i g g e r e d i n t o e x i s t e n c e b y t h e c h i l d ' s early e x p e r i e n c e , t h e n t h e child c a n i m m e d i a t e l y e m b a r k o n t h e i m p o r t a n t task of l e a r n i n g t h e a c c u m u l a t e d w i s d o m of its s o c i e t y . S o t h e i n n a t e n e s s of f o l k - p s y c h o l o g y is j u s t w h a t o n e m i g h t h a v e e x p e c t e d evolutionary selection to deliver. C r e a t u r e s ,

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s u c h a s o u r s e l v e s , w h o s e survival d e p e n d s crucially u p o n m u t u a l k n o w l e d g e of o n e a n o t h e r ' s p s y c h o l o g y , will s u r v i v e b e s t if that k n o w l e d g e is i n n a t e . I n d e e d , r e c e n t e v i d e n c e s u g g e s t s that it w a s t h e e v o l u t i o n of a distinctively social i n t e l l i g e n c e that g a v e t h e p r i m a r y i m p e t u s to t h e e v o l u t i o n of h u m a n i n t e l l i g e n c e in g e n e r a l . S t u d i e s of t h e b e h a v i o u r of o u r c l o s e s t a n i m a l c o u s i n s in t h e w i l d , c h i m p a n z e e s , s h o w c o n v i n c i n g l y that t h e y , t o o , h a v e at l e a s t a p r i m i t i v e m o d e l of their f e l l o w s ' p s y c h o l o g y . T h e s u g g e s t i o n t h e n m a d e is that o n c e this m o d e l is i n n a t e l y g i v e n , n e w m o d e s of social i n t e r a c t i o n ( c o - o p e r a t i o n as well a s c o m p e t i t i o n ) b e c o m e p o s s ible. T h e a d v a n t a g e s in survival of s u c h i n t e r a c t i o n w o u l d b e s o d e c i s i v e that o n e w o u l d e x p e c t t h e m o d e l to h a v e b e c o m e rapidly m o r e s o p h i s t i c a t e d , p r o l i f e r a t i n g in t h e e n d i n t o fullb l o w n h u m a n i n t e l l i g e n c e . T h i s story is certainly p l a u s i b l e e n o u g h to s u p p o r t f u r t h e r t h e s u g g e s t i o n t h a t h u m a n folkp s y c h o l o g y is i n n a t e . 7

Is F o l k - P s y c h o l o g y C o r r e c t ? Recall that in o r d e r to qualify as k n o w l e d g e , a b e l i e f m u s t at least b e true. S o if f o l k - p s y c h o l o g y is to b e n o t o n l y i n n a t e , b u t i n n a t e l y k n o w n , it m u s t c o n s t i t u t e a c o r r e c t t h e o r y of t h e m i n d . S o far w e h a v e b e e n a s s u m i n g that it is i n d e e d c o r r e c t , b u t m a n y h a v e d e n i e d t h i s . T h e y h a v e m a i n t a i n e d that t h e r e is n o m o r e r e a s o n t o b e l i e v e f o l k - p s y c h o l o g y to b e correct t h a n t h e r e is to b e l i e v e in t h e c o r r e c t n e s s of f o l k - m e d i c i n e or folk-religion. B u t in that c a s e it is h a r d to s e e w h y f o l k - p s y c h o l o g y s h o u l d b e s o s t a g g e r i n g l y s u c c e s s f u l . O f c o u r s e it is n o t complete, s i n c e t h e r e a r e m a n y p u z z l i n g facts a b o u t o u r p s y c h o l o g y t h a t it c a n n o t e x p l a i n (for e x a m p l e , v a r i o u s f o r m s of m e n t a l i l l n e s s ) . B u t its d e g r e e of s u c c e s s w i t h i n its d o m a i n ( n a m e l y , n o r m a l c o n s c i o u s m e n t a l life) c a n b e m e a s u r e d b y t h e s u c c e s s of t h e s p e c i e s as a w h o l e . F o r it is f o l k - p s y c h o l o g y , a s w e h a v e s a i d , t h a t u n d e r l i e s o u r ability b o t h to c o o p e r a t e a n d t o c o m m u n i c a t e i n f o r m a t i o n , 8

S e e t h e p a p e r s c o l l e c t e d in R. B y r n e a n d A . W h i t e n ( e d s . ) , Intelligence ( O x f o r d : O x f o r d U n i v e r s i t y P r e s s , 1 9 8 8 ) . S e e e . g . S t i c h , From Folk Psychology. 7

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w h i c h in t u r n a r e t h e v e r y f o u n d a t i o n s of h u m a n society a n d human progress. It m i g h t b e said in reply that h u m a n c o m m u n i t i e s h a v e f l o u r i s h e d a n d p r o s p e r e d d e s p i t e their m e m b e r s ' h a v i n g h a d m a n y false b e l i e f s — f o r e x a m p l e , b e l i e f s in m a g i c a n d w i t c h c r a f t . B u t t h e d i f f e r e n c e b e t w e e n s u c h beliefs a n d t h o s e of folkp s y c h o l o g y is that t h e latter are i m p l i c a t e d in a l m o s t e v e r y a s p e c t o f o u r practical lives. Beliefs in m a g i c , in c o n t r a s t , w h i l e perhaps b e i n g highly valued by those w h o possess t h e m , are relatively p e r i p h e r a l . It is n o t s u r p r i s i n g that s o c i e t i e s s h o u l d flourish d e s p i t e their m e m b e r s ' h a v i n g false b e l i e f s . W h a t would b e s u r p r i s i n g is that t h o s e b e l i e f s s h o u l d be o n e s o n w h i c h t h e w h o l e fabric of c o - o p e r a t i o n a n d c o m m u n i c a t i o n d e p e n d s . A d d i t i o n a l l y , if w e r e g a r d s o m e of t h e a r g u m e n t s g i v e n earlier as s u c c e s s f u l in e s t a b l i s h i n g n a t i v i s m , t h e n t h e i n n a t e n e s s of f o l k - p s y c h o l o g y p r o v i d e s u s w i t h g o o d r e a s o n for b e l i e v i n g it to b e c o r r e c t . F o r w h y s h o u l d t h e beliefs in q u e s t i o n b e i n n a t e unless t h e y a r e true? It m i g h t b e replied that m a n y i n n a t e f e a t u r e s o f o r g a n i s m s i n v o l v e m i s r e p r e s e n t a t i o n s of the e n v i r o n m e n t . F o r e x a m p l e , d u c k l i n g s s e e m to h a v e an i n n a t e b e l i e f that t h e first m o v i n g t h i n g t h e y s e e is their m o t h e r . S i n c e this will l e a d t h e m m i s t a k e n l y to a t t a c h t h e m s e l v e s to a h u m a n b e i n g , if a h u m a n is t h e first m o v i n g t h i n g t h e y s e e , it m i g h t b e a r g u e d t h a t t h e r e is n o g e n e r a l r e a s o n for t h i n k i n g that i n n a t e b e l i e f s will b e t r u e . B u t o n e d i f f e r e n c e b e t w e e n t h e t w o c a s e s lies in t h e r e l a t i v e stability of t h e d u c k l i n g e n v i r o n m e n t . ( A n o t h e r is that t h e m e c h a n i s m in t h e d u c k l i n g is p r o b a b l y n o t p r o p e r l y c h a r a c t e r i z e d a s a belief. A r e w e really p r e p a r e d to a p p l y t h e p r a c t i c a l - r e a s o n i n g - m o d e l h e r e ? ) S i n c e t h e m o t h e r d u c k is a l m o s t a l w a y s t h e first t h i n g a d u c k l i n g will s e e , it is e a s y to u n d e r s t a n d w h y t h e m e c h a n i s m of i m p r i n t i n g s h o u l d h a v e b e e n s e l e c t e d in e v o l u t i o n . H u m a n f o l k - p s y c h o l o g y , in c o n t r a s t , h a s to s e r v e in a v e r y w i d e a n d u n p r e d i c t a b l e r a n g e of c i r c u m s t a n c e s . M u c h of t h e s u c c e s s of h u m a n b e i n g s as a s p e c i e s lies in their ability to a d a p t to a l m o s t a n y e n v i r o n m e n t , a s w e l l as in their ability to accumulate knowledge about the world around them and hence a d a p t it, i n t u r n , to h u m a n n e e d s . S o t h e i n n a t e b a s i s o f t h e s e abilities ( n a m e l y o u r m u t u a l b e l i e f s a b o u t h u m a n p s y c h o l o g y ) has to b e workable w h a t e v e r the circumstances, and whatever

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o t h e r b e l i e f s a n d p r a c t i c e s are c u r r e n t in t h e c o m m u n i t y . It is h a r d to s e e h o w a n y t h i n g c o u l d s e r v e this p u r p o s e except t h e truth. I c o n c l u d e that w e h a v e g o o d r e a s o n to t h i n k that t h e g e n e r a l i z a t i o n s of f o l k - p s y c h o l o g y are b o t h i n n a t e l y b e l i e v e d a n d t r u e . T h e n , s i n c e it a p p e a r s that t h e e v o l u t i o n a r y s e l e c t i o n of b e l i e f s a n d b e l i e f - a c q u i s i t i o n m e c h a n i s m s (at least in c r e a t u r e s as c o m p l e x a n d a d a p t a b l e as o u r s e l v e s ) is a reliable p r o c e s s , f o l k - p s y c h o l o g y will c o u n t a s i n n a t e l y k n o w n . S o w e d o h a v e s u b s t a n t i v e i n n a t e k n o w l e d g e of a n a s p e c t of t h e w o r l d , n a m e l y t h e p s y c h o l o g y of m e m b e r s of o u r o w n s p e c i e s .

Folk-Psychological C o n c e p t s W h a t of the c o n s t i t u e n t c o n c e p t s of o u r c o m m o n - s e n s e b e l i e f s about the mind? Are they, too, innate? O r are they rather a c q u i r e d from e x p e r i e n c e prior to t h e t r i g g e r i n g of o u r i n n a t e b e l i e f s ? (Recall from c h a p t e r 4 that o u r p o s s e s s i o n of i n n a t e k n o w l e d g e n e e d n o t entail that w e also p o s s e s s i n n a t e c o n c e p t s . ) O n e a c c o u n t of m e n t a l c o n c e p t s that m i g h t a l l o w t h e m to be derived from experience would be the Cartesian model. This h o l d s that all m e n t a l s t a t e s a r e t r a n s p a r e n t l y available to c o n s c i o u s n e s s , o u r c o n c e p t s of t h e m b e i n g s i m p l e r e c o g n i t i o n a l c a p a c i t i e s . T h e n p e r h a p s i n t r o s p e c t i o n of o u r o w n m e n t a l s t a t e s m i g h t be sufficient for u s to a c q u i r e o u r c o n c e p t i o n s of t h e m , e v e n if it is n o t sufficient for u s to learn of t h e c a u s a l r e l a t i o n s b e t w e e n t h e m , as w e n o t e d a b o v e . T h e C a r t e s i a n c o n c e p t i o n of m e n t a l c o n c e p t s is n o w a l m o s t u n i v e r s a l l y r e j e c t e d , for at least t w o r e a s o n s . T h e first is that it m a k e s it v e r y difficult t o e x p l a i n h o w w e c a n h a v e k n o w l e d g e of t h e m e n t a l s t a t e s of o t h e r p e o p l e . If o u r c o n c e p t i o n of e a c h t y p e of m e n t a l state is g i v e n p u r e l y b y its i n n e r s u b j e c t i v e q u a l i t y , w h i c h w e c a n of n e c e s s i t y k n o w o n l y f r o m o u r o w n c a s e , t h e n it is p r o b l e m a t i c , to s a y t h e least, h o w w e c a n k n o w that o t h e r people h a v e similar subjective feelings in similar c i r c u m s t a n c e s . 9

T h e s e c o n d o b j e c t i o n to t h e C a r t e s i a n a c c o u n t is t h a t t h e r e a r e m a n y t y p e s of m e n t a l s t a t e for w h i c h it d o e s n o t e v e n b e g i n t o l o o k p l a u s i b l e . C o n s c i o u s n e s s o f m y o w n b e l i e f s a n d d e s i r e s , in 9

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particular, s u r e l y c a n n o t b e a m a t t e r of i m m e d i a t e r e c o g n i t i o n . For in virtue of what w o u l d t h e y b e r e c o g n i z e d ? T h e s e s t a t e s d o n o t h a v e d i s t i n c t i v e feels to t h e m , in t h e w a y that p a i n s a n d o t h e r s e n s a t i o n s a r g u a b l y d o . I n d e e d , s i n c e t h e r e are p o t e n t i a l l y infinitely m a n y distinct beliefs a n d d e s i r e s , of w h i c h I h a v e c o n c e p t s before I c o m e to h a v e t h e m , t h e r e is a real p r o b l e m h e r e as to h o w I m i g h t b e s u p p o s e d to h a v e a c q u i r e d t h e s e c o n c e p t s from introspection. T h e r e is n o u n a n i m i t y as to w h a t a c c o u n t of o u r m e n t a l c o n c e p t s s h o u l d r e p l a c e t h e C a r t e s i a n o n e , but f u n c t i o n a l i s m is now the most popular. T h i s h o l d s that m e n t a l s t a t e s a r e i n d i v i d u a t e d b y their normal causal role, or f u n c t i o n . I n d e e d , the f u n c t i o n a l i s t v i e w is that m e n t a l c o n c e p t s gain their s e n s e f r o m their p o s i t i o n w i t h i n t h e g e n e r a l i z a t i o n s of f o l k - p s y c h o l o g y . K n o w i n g w h a t a b e l i e f is, for e x a m p l e , is a m a t t e r of k n o w i n g h o w it t e n d s to interact w i t h o t h e r m e n t a l s t a t e s s u c h as d e s i r e s and decisions. 10

T h e r e a r e p r o b l e m s with f u n c t i o n a l i s m that n e e d not d e t a i n u s h e r e . " S u f f i c e it to say that if f u n c t i o n a l i s m is c o r r e c t , t h e n m e n t a l c o n c e p t s , in b e i n g a c q u i r e d a l o n g w i t h f o l k - p s y c h o logical b e l i e f s , will b e i n n a t e if t h e latter a r e . I n d e e d , it l o o k s as if t h e s a m e will b e true o n a n y viable a l t e r n a t i v e to C a r t e s i a n i s m . F o r , a s C h o m s k y p o i n t s o u t , o u r m e n t a l c o n c e p t s a p p e a r to b e c o n n e c t e d to o n e a n o t h e r in very m a n y c o m p l e x a n d s u b t l e w a y s . T h i s m e a n s t h a t it will b e h a r d to e x p l a i n h o w t h e s e c o n c e p t s a r e a c q u i r e d s o fast, a n d o n s u c h s l e n d e r e x p o s u r e , u n l e s s t h e y a r e s u p p o s e d to b e i n n a t e . 1 2

T h e r e is o n e i s s u e that w e d o n e e d to p u r s u e f u r t h e r , s i n c e it b e a r s o n t h e likely c o r r e c t n e s s of f o l k - p s y c h o l o g y . T h i s is t h e q u e s t i o n w h e t h e r , in g a i n i n g their s e n s e f r o m b e i n g e m b e d d e d within folk-psychological beliefs, mental concepts are e m p l o y e d as natural-kind terms. ( A n a t u r a l - k i n d t e r m is o n e that is u s e d w i t h t h e i n t e n t i o n of ' d i v i d i n g n a t u r e at t h e j o i n t s ' , in P l a t o ' s p h r a s e — t h a t i s , of p i c k i n g o u t a class of t h i n g s that w o u l d b e r e c o g n i z e d a s s u c h in a c o m p l e t e d s c i e n c e . ) T o t a k e t h e v i e w t h a t m e n t a l c o n c e p t s are e m p l o y e d a s n a t u r a l - k i n d t e r m s is t o S e e t h e p a p e r s c o l l e c t e d in p t . 3 of N e d B l o c k ( e d . ) , Readings Psychology I ( L o n d o n : M e t h u e n , 1 9 8 0 ) . 1 0

F o r f u r t h e r d i s c u s s i o n , s e e m y Introducing m a n y o f t h e p a p e r s m e n t i o n e d in n . 10 a b o v e . 1 2

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26-34.

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t h i n k of f o l k - p s y c h o l o g y a s a p r i m i t i v e f o r m of scientific t h e o r y of t h e m i n d , a s its v e r y n a m e s u g g e s t s . T h e n if, a s is p o s s i b l e , a c o m p l e t e d scientific p s y c h o l o g y w o u l d n o t e m p l o y s u c h n o t i o n s as ' b e l i e f , ' d e s i r e ' , or ' p a i n ' , it will t u r n o u t that t h e s e t e r m s fail to refer (just as ' p h l o g i s t o n ' fails to r e f e r ) , a n d t h a t t h e w h o l e of f o l k - p s y c h o l o g y s h o u l d b e r e j e c t e d as false. H o w e v e r , w h e t h e r or n o t a b o d y of b e l i e f s c o n s t i t u t e s a scientific t h e o r y is at least partly a m a t t e r of t h e i n t e n t i o n s w i t h w h i c h it is h e l d . In p a r t i c u l a r , w e h a v e to b e p r e p a r e d to a b a n d o n t h e t h e o r y if a b e t t e r o n e e m e r g e s . B u t w e d o n o t h a v e this a t t i t u d e t o w a r d s o u r c o m m o n - s e n s e p s y c h o l o g y . If a f u t u r e scientific p s y c h o l o g y finds that it can o p e r a t e b e s t w i t h o u t s u c h n o t i o n s as ' p a i n ' or ' b e l i e f , w e will n o t a c c e p t t h a t t h e r e a r e n o s u c h t h i n g s as p a i n s a n d b e l i e f s , a n y m o r e t h a n w e a c c e p t t h a t t a b l e s are n o t really solid o b j e c t s in t h e light of t h e d i s c o v e r i e s of m o d e r n p h y s i c s . R a t h e r , w e will c o n t i n u e to o p e r a t e w i t h o u r f o l k - p s y c h o l o g i c a l n o t i o n s a n d g e n e r a l i z a t i o n s alongside s c i e n t ific p s y c h o l o g y . W h i l e I h a v e a r g u e d t h a t f o l k - p s y c h o l o g y is a largely c o r r e c t t h e o r y of t h e m i n d , it d o e s n o t f o l l o w that it is a scientific t h e o r y of t h e m i n d . ( C o m p a r e f o l k - p h y s i c s , w h i c h i n c l u d e s s u c h t r u t h s as ' T h e c h a i r b r o k e b e c a u s e D a v i d w a s t o o h e a v y for i f . W e retain this as t r u e , d e s p i t e t h e fact t h a t ' c h a i r ' does not designate a natural kind.) M y c o n c l u s i o n is that w e d o i n d e e d p o s s e s s a b o d y o f reliably c a u s e d t r u e beliefs that a r e i n n a t e , n a m e l y o u r b e l i e f s a b o u t o u r own psychology.

9 Powers of Mind: The Core of Empiricism IN this c h a p t e r I shall c o n s i d e r w h e t h e r t h e e s s e n t i a l c o n c e r n s of e m p i r i c i s t s c a n b e c h a r a c t e r i s e d s o as to b e c o n s i s t e n t w i t h n a t i v i s m . If t h e y c a n n o t , t h e n e m p i r i c i s m s h o u l d n o w b e p r o n o u n c e d d e a d , g i v e n t h e s t r e n g t h of t h e n a t i v i s t c a s e .

The Problem of Unity W h i c h of t h e t w o m a i n s t r a n d s in e m p i r i c i s m ( o p p o s i t i o n to n a t i v i s m , a n d o p p o s i t i o n to t h e s u b s t a n t i v e a priori) c o n s t i t u t e s its true c o r e ? O r s h o u l d t h e e s s e n c e of t h e e m p i r i c i s t p r o j e c t b e d e s c r i b e d in s o m e third w a y that w o u l d e m b r a c e b o t h ? C l e a r l y t h e t w o s t r a n d s are at least partly i n d e p e n d e n t of o n e a n o t h e r . O n e c o u l d b e l i e v e in t h e e x i s t e n c e of s u b s t a n t i v e a priori k n o w l e d g e w i t h o u t e n d o r s i n g n a t i v i s m . O n e c o u l d , for e x a m p l e , b e l i e v e in a s p e c i a l faculty of i n t e l l e c t u a l i n t u i t i o n , as m a n y p l a t o n i s t s h a v e d o n e . T h i s w o u l d a c c o r d u s k n o w l e d g e of t h e a b s t r a c t r e a l m in a q u a s i - p e r c e p t u a l m a n n e r . A l t h o u g h t h e faculty itself w o u l d b e i n n a t e (just as t h e f a c u l t y of v i s i o n is i n n a t e , e v e n for a n e m p i r i c i s t ) , t h e b e l i e f s t h a t it g i v e s r i s e to w o u l d n o t b e . T h e n , s i n c e b e l i e f in t h e s u b s t a n t i v e a priori d o e s n o t entail a b e l i e f in n a t i v i s m , t h e sort of a t t a c k t h a t e m p i r i c i s t s h a v e m o u n t e d o n t h e s u b s t a n t i v e a priori c a n n o t m e r e l y h a v e b e e n p a r t of their c a m p a i g n a g a i n s t n a t i v i s m . In c o n t r a s t , k n o w l e d g e t h a t is i n n a t e w o u l d at t h e s a m e t i m e b e a priori, at l e a s t in t h e s e n s e o f n o t b e i n g l e a r n e d f r o m e x p e r i e n c e . S o t o a c c e p t t h a t t h e r e is s u b s t a n t i v e i n n a t e k n o w l e d g e w o u l d c o m m i t o n e to b e l i e f i n s o m e f o r m s of s u b s t a n t i v e a priori k n o w l e d g e . It m i g h t t h e n b e s u g g e s t e d t h a t the empiricist opposition to nativism m a y b e motivated by their

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o p p o s i t i o n to t h e s u b s t a n t i v e a priori. H o w e v e r , this w o u l d h a r d l y w a r r a n t a n a t t a c k o n n a t i v i s m a s s u c h , of t h e k i n d that w e find in L o c k e . F o r a n attack o n t h e s u b s t a n t i v e a priori w o u l d n o t , o n a n y a c c o u n t of t h e m a t t e r , b e a n attack o n all f o r m s o f i n n a t e n e s s . It w o u l d o n l y b e i n n a t e k n o w l e d g e that w o u l d b e u n d e r m i n e d , leaving innate beliefs, concepts, and informationbearing mental structures untouched. Yet empiricists have characteristically d e n i e d all t h e s e i d e a s a l s o . S o their m o t i v a t i o n c a n n o t h a v e b e e n a m e r e c o n s e q u e n c e of their o p p o s i t i o n to t h e s u b s t a n t i v e a priori. It m i g h t be s u g g e s t e d that I h a v e e r r e d in c h a r a c t e r i z i n g e m p i r i c i s m p u r e l y n e g a t i v e l y , as i n v o l v i n g b o t h t h e denial of n a t i v i s m a n d t h e denial of s u b s t a n t i v e a priori k n o w l e d g e . P e r h a p s a positive c h a r a c t e r i z a t i o n m i g h t e m b r a c e b o t h . I n d e e d s o : that is j u s t w h a t 1 a m n o w s e e k i n g . B u t w e c a n n o t take t h e o b v i o u s ( a n d traditional) o p t i o n , a n d claim that e m p i r i c i s m c o n s i s t s in t h e d e m a n d that all s u b s t a n t i v e k n o w l e d g e m u s t b e g r o u n d e d in e x p e r i e n c e . W h i l e s u c h a d e m a n d d o e s i n d e e d rule out b o t h i n n a t e k n o w l e d g e a n d a priori k n o w l e d g e , w e s h o u l d still b e u n a b l e to e x p l a i n the e m p i r i c i s t o p p o s i t i o n to i n n a t e concepts, beliefs, and information-bearing mental structures, n o n e of w h i c h n e e d c o u n t as k n o w l e d g e . S i n c e c o n c e p t s , for e x a m p l e , m i g h t b e i n n a t e a l t h o u g h n o k n o w l e d g e is, t h e e m p i r i c i s t i n s i s t e n c e that all k n o w l e d g e m u s t b e g r o u n d e d in e x p e r i e n c e c a n n o t e x p l a i n their belief that all c o n c e p t s , t o o , must be derived from experience. N o r will it h e l p to s u p p o s e that t h e b a s i s of e m p i r i c i s m c o n s i s t s in t h e p o s i t i v e d e m a n d that all c o n c e p t s s h o u l d b e a c q u i r e d from e x p e r i e n c e . W h i l e this m a y b e t h o u g h t ( w r o n g l y , as w e s a w in c h a p t e r 4) to entail that t h e r e c a n b e n o i n n a t e beliefs or k n o w l e d g e , it c a n n o t e x p l a i n t h e e m p i r i c i s t o p p o s i t i o n to i n f o r m a t i o n - b e a r i n g m e n t a l s t r u c t u r e s . N o r is it o b v i o u s w h y it s h o u l d b e t h o u g h t to rule o u t t h e possibility of s u b s t a n t i v e a priori k n o w l e d g e . F o r it m i g h t b e m a i n t a i n e d t h a t w e c a n arrive at s u b s t a n t i v e k n o w l e d g e of s o m e a s p e c t of t h e w o r l d b y thought alone, despite those thoughts employing empirically acquired concepts. For example, s o m e o n e could claim that while m a t h e m a t i c a l concepts are a b s t r a c t a b l e f r o m e x p e r i e n c e , m a t h e m a t i c a l knowledge d e p e n d s r a t h e r u p o n a s p e c i a l faculty of intellectual intuition. M o r e o v e r , b o t h of t h e a b o v e p r o p o s a l s w o u l d still l e a v e u s in

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n e e d of a n a c c o u n t of t h e m o t i v a t i o n b e h i n d t h e positive d e m a n d . W h y should o n e b e l i e v e that all k n o w l e d g e , or all c o n c e p t s , m u s t b e g r o u n d e d in e x p e r i e n c e ? I n d e e d , for all that h a s s o far b e e n s a i d , it m a y t u r n o u t o n i n v e s t i g a t i o n that t h e p o s i t i v e c h a r a c t e r i z a t i o n s g i v e n a b o v e s e r v e m e r e l y to m a s k an u n d e r l y i n g d i s u n i t y of m o t i v e . In w h i c h c a s e w e s h o u l d h a v e made n o progress with our question w h e t h e r empiricists, while r e m a i n i n g true to their e s s e n t i a l c o n c e r n s , c a n b e b r o u g h t to an a c c e p t a n c e of n a t i v i s m . A r a t h e r d i f f e r e n t p r o p o s a l m i g h t b e that it is p h e n o m e n a l i s m t h a t is t h e c o r e e m p i r i c i s t c o m m i t m e n t . For if all k n o w l e d g e a n d t h o u g h t m u s t in the e n d r e d u c e to p a t t e r n s w i t h i n o u r o w n s u b j e c t i v e e x p e r i e n c e , t h e n p r e s u m a b l y t h e r e can b e n o s u b s t a n tive a priori k n o w l e d g e , n o r a n y k n o w l e d g e that is i n n a t e . M o r e o v e r , if t h e e x p e r i e n c e in q u e s t i o n c o n s i s t s of u n c o n c e p t u a l i z e d a n d u n s t r u c t u r e d s e n s e - d a t a , as p h e n o m e n a l i s t s h a v e traditionally m a i n t a i n e d , t h e n p r e s u m a b l y n e i t h e r c o n c e p t s n o r i n f o r m a t i o n - b e a r i n g m e n t a l s t r u c t u r e s can b e i n n a t e e i t h e r . B u t this s u g g e s t i o n h a s a l r e a d y b e e n d i s c u s s e d , a n d r e j e c t e d , in c h a p t e r 1. R a t h e r , t h e fact t h a t m a n y e m p i r i c i s t s h a v e e m b r a c e d p h e n o m e n a l i s m is b e s t e x p l a i n e d in t e r m s of their c o m m i t m e n t to t h e t w o m a i n n e g a t i v e s t r a n d s a l r e a d y m e n t i o n e d , t o g e t h e r w i t h their f o u n d a t i o n a l i s m . A final s u g g e s t i o n m i g h t b e that t h e b a s i c c o n c e r n of t h e early e m p i r i c i s t s w a s w i t h m a t t e r s of j u s t i f i c a t i o n . P e r h a p s all that u n i f i e s o p p o s i t i o n t o n a t i v i s m a n d to t h e s u b s t a n t i v e a priori is that n e i t h e r belief in i n n a t e c o n c e p t s or k n o w l e d g e , n o r t h e belief that w e m a y o b t a i n s u b s t a n t i v e i n f o r m a t i o n a b o u t t h e w o r l d t h r o u g h r e a s o n a l o n e , is sufficiently justified to b e a c c e p t a b l e . In o n e w a y this p r o p o s a l c o n v e r g e s w i t h m y o w n h y p o t h e s i s , to b e d e v e l o p e d s h o r t l y . B u t I d o n o t s e e h o w it c a n s e r v e , o n its o w n , to c a p t u r e t h e n a t u r e of t h e e m p i r i c i s t o b j e c t i o n s t o n a t i v i s m a n d t h e s u b s t a n t i v e a priori. F o r w e s h o u l d still w a n t to u n d e r s t a n d j u s t why all c l a i m s to s u c h k n o w l e d g e m u s t be insufficiently justified.

A Historical H y p o t h e s i s M y o w n s u g g e s t i o n is quite d i f f e r e n t . I p r o p o s e that t h e c o r e of e m p i r i c i s m s h o u l d b e s e e n as l y i n g in t h e i d e a that e p i s t e m o l o g y

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is c o n s t r a i n e d b y s c i e n c e , a n d b y p s y c h o l o g y in particular. In m y v i e w , t h e m o s t b a s i c e m p i r i c i s t c o m m i t m e n t is t o t h e t h e s i s that c l a i m s to k n o w l e d g e s h o u l d o n l y b e g r a n t e d o n c o n d i t i o n that t h e y c a n b e r e n d e r e d c o n s i s t e n t w i t h o u r b e s t t h e o r y of t h e p o w e r s of t h e h u m a n m i n d , a n d of t h e m i n d ' s n a t u r a l m o d e s of a c c e s s to reality. N o k n o w l e d g e - c l a i m s a r e to b e a l l o w e d , e x c e p t w h e r e w e c a n p r o v i d e at least t h e b e g i n n i n g s of a naturalistic a c c o u n t of t h e p r o c e s s e s t h r o u g h w h i c h that k n o w l e d g e is a c q u i r e d . ( A natural p r o c e s s is o n e that falls u n d e r c a u s a l l a w s . It is o n e that c a n in p r i n c i p l e b e s u b s u m e d w i t h i n t h e l a w s of n a t u r e , w h e t h e r t h o s e l a w s are k n o w n b y u s or n o t , a n d w h a t e v e r f o r m t h e y m i g h t ultimately take; it is n o t p r e s u p p o s e d that all n a t u r a l p r o c e s s e s a r e p h y s i c a l , for e x a m p l e . ) B u t this is n o t to say that e p i s t e m o l o g y t h e n b e c o m e s a b s o r b e d into n a t u r a l s c i e n c e . ' R a t h e r , it is to p l a c e an a d d i t i o n a l n o r m a t i v e c o n s t r a i n t on e p i s t e m o l o g y — n a m e l y , that w e s h o u l d b e able to s e e h o w o u r c l a i m s to k n o w l e d g e m i g h t b e fitted i n t o t h e f r a m e w o r k of a natural s c i e n c e . O n this a c c o u n t , the basic r e a s o n w h y early e m p i r i c i s t s d e n i e d the e x i s t e n c e of i n n a t e k n o w l e d g e a n d c o n c e p t s w a s t h a t the o n l y t h e o r y available to t h e m at t h e t i m e , of t h e p r o c e s s t h r o u g h w h i c h a n i t e m m i g h t c o m e to b e i n n a t e , w a s a nonnatural o n e , n a m e l y direct i n t e r v e n t i o n by G o d . A l t h o u g h t h e early e m p i r i c i s t s w o u l d h a v e g r a n t e d that i n t e r v e n t i o n b y G o d w a s c o n c e p t u a l l y p o s s i b l e , it c o n f l i c t e d w i t h t h e i r overall a t t e m p t to fit o u r idea of o u r s e l v e s a n d o u r k n o w l e d g e i n t o a b r o a d l y scientific f r a m e w o r k . If this w e r e really t h e r e a s o n w h y t h e early e m p i r i c i s t s r e j e c t e d n a t i v i s m , t h e n w h y did t h e y n o t s a y s o ? It m a y b e t h a t w h a t I a m calling their c o r e c o m m i t m e n t f o r m e d s u c h a f u n d a m e n t a l part of their o u t l o o k a s to b e a l m o s t i n v i s i b l e . A l t e r n a t i v e l y , their real a r g u m e n t m a y n o t h a v e b e e n easily e x p r e s s i b l e in p u b l i c , for political r e a s o n s . M o s t early e m p i r i c i s t s w e r e also t h e i s t s , a n d e v e n t h o s e w h o w e r e n o t h a d to r e s p e c t t h e i m m e n s e political p o w e r of t h e C h u r c h . A n a t t a c k u p o n n a t i v i s m o n t h e g r o u n d s t h a t it r e q u i r e s u s to b e l i e v e in G o d ' s 2

T h i s is Q u i n e ' s p o s i t i o n . S e e From a Logical Point of View, a n d a l s o Relativity ( N e w Y o r k : C o l u m b i a U n i v e r s i t y P r e s s , 1 9 6 9 ) . 1

Ontological

W i t n e s s t h e l e n g t h s t o w h i c h H u m e h a d t o g o in d i s g u i s i n g h i s r e a l v i e w s in The Dialogues Concerning Natural Religion. 2

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i n t e r v e n t i o n i n t h e h u m a n m i n d m i g h t h a v e s e e m e d like a direct attack u p o n t h e i s m . F o r if G o d e x i s t s , w h y s h o u l d h e n o t i n t e r v e n e in t h e n a t u r a l w o r l d if h e c h o o s e s to d o s o ? T h e r e is really n o argument for i n s i s t i n g t h a t n a t u r a l e v e n t s a d m i t of naturalistic e x p l a n a t i o n s , e x c e p t t h e s u c c e s s o f s c i e n c e in t h e l o n g r u n . I s u g g e s t t h a t i n s t e a d of f a c i n g this i s s u e h e a d - o n , a n d o p e n l y d e c l a r i n g their c o m m i t m e n t to t h e e x p l a n a t o r y a d e q u a c y of s c i e n c e , t h e early e m p i r i c i s t s m a y h a v e c h o s e n e i t h e r to a r g u e a g a i n s t n a t i v i s m o n q u i t e o t h e r g r o u n d s , or to a s s u m e its falsity a n d r e n d e r t h e h y p o t h e s i s of d i v i n e i n t e r v e n t i o n u n n e c e s s a r y , b y p r o v i d i n g a n a l t e r n a t i v e a c c o u n t of t h e g e n e s i s of h u m a n knowledge through experience. N o t e that m y p r o p o s a l is c o n s i s t e n t w i t h reliabilism a s a t h e o r y of k n o w l e d g e . F o r t h e t h e s i s in q u e s t i o n b e l o n g s t o epistemology, being concerned with what w e may reasonably b e l i e v e o u r s e l v e s to k n o w (that i s , w i t h s e c o n d - o r d e r k n o w l e d g e ) , r a t h e r t h a n w i t h first-order k n o w l e d g e a s s u c h . A n e m p i r i c i s t c a n g r a n t that t h e r e m a y , a s a m a t t e r of fact, b e k n o w l e d g e of w h i c h w e c a n p r o v i d e n o naturalistic a c c o u n t . F o r w e m a y h a v e t r u e beliefs that a r e in fact c a u s e d b y s o m e reliable p r o c e s s , b u t w h e r e t h e p r o c e s s in q u e s t i o n is u n t h i n k a b l e i n t e r m s of c u r r e n t s c i e n c e . In s u c h a c a s e w e w o u l d i n d e e d h a v e first-order k n o w l e d g e , b u t a n e m p i r i c i s t w o u l d insist that w e n e v e r t h e l e s s h a v e n o right to rely u p o n t h e b e l i e f s in q u e s t i o n . T h o s e beliefs s h o u l d at l e a s t b e s u s p e n d e d ( w e s h o u l d h o l d b a c k f r o m t h e s e c o n d - o r d e r belief that t h e y c o n s t i t u t e k n o w l e d g e ) until w e c a n b e g i n to p r o v i d e s o m e naturalistic a c c o u n t o f t h e i r m o d e of acquisition.

Explanatory A d v a n t a g e s T h e m a i n a d v a n t a g e of m y p r o p o s a l is that it e n a b l e s u s to u n i f y t h e early e m p i r i c i s t o b j e c t i o n s to n a t i v i s m a n d to t h e s u b s t a n t i v e a priori (particularly p l a t o n i s m ) . In b o t h c a s e s k n o w l e d g e - c l a i m s w e r e r e j e c t e d b e c a u s e t h e r e w a s available n o n a t u r a l i s t i c a c c o u n t of t h e b e l i e f - a c q u i s i t i o n p r o c e s s e s i n v o l v e d . In-the c a s e 3

T h i s is w h y t h e belief t h a t w e h a v e e i t h e r i n n a t e o r s u b s t a n t i v e a p r i o r i k n o w l e d g e t u r n s o u t to b e unjustified, t h u s c o n v e r g i n g with t h e justificationalist a c c o u n t o f e m p i r i c i s t m o t i v a t i o n s o u t l i n e d e a r l i e r . F o r in t h e a b s e n c e o f a n y 3

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of n a t i v i s m , t h e h y p o t h e s e s that e i t h e r k n o w l e d g e , c o n c e p t s , or information-bearing mental structures are innate w e r e rejected b e c a u s e t h e y s e e m e d to r e q u i r e n o n - n a t u r a l i n t e r v e n t i o n in t h e h u m a n m i n d by a v e r a c i o u s G o d . In the c a s e of t h e s u b s t a n t i v e a priori, t h e o b j e c t i o n w a s that t h e r e c o u l d b e n o naturalistic e x p l a n a t i o n of h o w r e a s o n c o u l d h a v e a c q u i r e d t h e p o w e r to g e n e r a t e k n o w l e d g e of a n y t h i n g o u t s i d e itself. It w o u l d a p p a r e n t l y h a v e r e q u i r e d G o d ' s i n t e r v e n t i o n to e n s u r e that t h e s t r u c t u r e of o u r r e a s o n accurately m a p p e d t h e s t r u c t u r e of t h e appropriate mind-independent realm. T h e platonist hypothesis of a special faculty of intellectual i n t u i t i o n , for e x a m p l e , w a s rejected b e c a u s e w e c a n n o t e v e n b e g i n to g i v e a n a c c o u n t of t h e p s y c h o l o g i c a l s t r u c t u r e o f s u c h a faculty, or of h o w t h e r e c o u l d be causal c o n t a c t b e t w e e n n e c e s s a r i l y e x i s t i n g a b s t r a c t e n t i t i e s a n d the h u m a n m i n d . Y e t t h e o n l y o t h e r a l t e r n a t i v e o p e n to a p l a t o n i s t , n a m e l y t h e s u g g e s t i o n that o u r k n o w l e d g e of the abstract realm is i n n a t e , b r i n g s u s b a c k to a n o n - n a t u r a l m o d e l of belief a c q u i s i t i o n o n c e a g a i n . G o d ' s i n t e r v e n t i o n w o u l d a p p a r e n t l y h a v e b e e n n e e d e d to e n s u r e that o u r i n n a t e beliefs w e r e true o f t h e a b s t r a c t r e a l m . M y p r o p o s a l also c o h e r e s well with t h e fact that t h e early e m p i r i c i s t s i m m e r s e d t h e m s e l v e s in e n q u i r i e s that w e r e q u i t e explicitly p s y c h o l o g i c a l . It is b e c a u s e t h e y t h o u g h t that t h e t h e o r y of k n o w l e d g e h a d to b e fitted i n t o a b r o a d l y scientific o u t l o o k , a n d r e n d e r e d c o n s i s t e n t with o u r b e s t scientific t h e o r i e s , that t h e y r e g a r d e d e p i s t e m o l o g i c a l a n d p s y c h o l o g i c a l questions as belonging essentially t o g e t h e r . M a n y c o m m e n t a t o r s , in c o n t r a s t , h a v e r e g a r d e d the c l o s e c o n j u n c t i o n of p s y c h o l o g i c a l w i t h e p i s t e m o l o g i c a l e n q u i r y as b e i n g s e r i o u s l y c o n f u s e d . T h e y h a v e said that it is o n e t h i n g to a s k h o w t h e m i n d actually w o r k s , a n d h o w beliefs a r e actually f o r m e d , a n d 4

naturalistic a c c o u n t of o u r m o d e of acquiring s u c h k n o w l e d g e w e are not justified in b e l i e v i n g it t o e x i s t , g i v e n a g e n e r a l c o m m i t m e n t t o t h e e x p l a n a t o r y a d e q u a c y o f s c i e n c e — s e e t h e d i s c u s s i o n in t h e final s e c t i o n of this c h a p t e r . T h e i r m o t i v a t i o n is t h e r e f o r e slightly d i f f e r e n t f r o m t h a t o f G o l d m a n in Epistemology and Cognition, w h o s e a p p r o a c h is o t h e r w i s e v e r y s i m i l a r . G o l d m a n t h i n k s p s y c h o l o g y is r e l e v a n t t o e p i s t e m o l o g y b e c a u s e , a s a reliabilist, h e t h i n k s it n e c e s s a r y t o i n v e s t i g a t e h o w reliable o u r b e l i e f - a c q u i s i t i o n p r o c e s s e s a c t u a l l y are. The c o n c e r n s of the early empiricists w e r e broader, in that they w e r e a t t e m p t i n g t o fit o u r p i c t u r e o f o u r s e l v e s a n d o u r k n o w l e d g e i n t o a scientific outlook. 4

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quite a n o t h e r to a s k w h a t w e c a n k n o w , a n d h o w . T h e o n e is a factual, t h e o t h e r s h o u l d b e a n o r m a t i v e , e n q u i r y . O n m y r e a d i n g of e m p i r i c i s m , h o w e v e r , t h e s e q u e s t i o n s are i n t i m a t e l y r e l a t e d to o n e a n o t h e r . F o r if e p i s t e m o l o g y is c o n s t r a i n e d b y p s y c h o l o g y , t h e n w e c a n n o t b e g i n to settle t h e q u e s t i o n of w h a t w e c a n k n o w w i t h o u t at l e a s t s k e t c h i n g t h e o u t l i n e of t h e v a r i o u s faculties a n d p s y c h o l o g i c a l p r o c e s s e s i n v o l v e d in t h e a c q u i s i t i o n of o u r b e l i e f s . M y a c c o u n t a l s o fits n e a t l y w i t h t h e w a y s in w h i c h b o t h L o c k e a n d H u m e explain t h e m o t i v a t i o n of their w o r k , as I shall s h o w in a m o m e n t . B e r k e l e y , h o w e v e r , m i g h t s e e m to r e p r e s e n t s o m e t h i n g of a p r o b l e m for m y r e a d i n g of e m p i r i c i s m , g i v e n t h e central place a c c o r d e d to G o d in his p h i l o s o p h y — t h o u g h e v e n h e r e the role of G o d is limited to s u p p l y i n g t h e data of e x p e r i e n c e ; G o d is n o t s u p p o s e d to i n t e r v e n e directly in the h u m a n m i n d . B u t , in fact, B e r k e l e y ' s m o t i v e s w e r e i n d e e d d i f f e r e n t . H e a d o p t e d e m p i r i c i s t p r e m i s s e s in o r d e r to s e r v e his o w n t h e o l o g i c a l p u r p o s e s , r a t h e r t h a n a s part of a n a t t e m p t to fit o u r v i e w of o u r s e l v e s a n d o u r k n o w l e d g e i n t o a b r o a d l y scientific f r a m e w o r k . I n s t e a d , his p r o j e c t w a s to d e f e n d t h e i s m f r o m w h a t h e t o o k to b e t h e t w i n t h r e a t s of m a t e r i a l i s m a n d a t h e i s m . H e t h e r e f o r e o u g h t n o t to b e c o u n t e d a s a n e m p i r i c i s t at all, o n m y a c c o u n t . N o w c o n s i d e r t h e c a s e of L o c k e . In t h e E p i s t l e to t h e R e a d e r of t h e Essay h e tells u s h o w , in t h e c o u r s e o f d i s c u s s i o n s w i t h f r i e n d s o n a n u n s p e c i f i e d topic, t h e y c a m e to feel that if t h e y w e r e to m a k e p r o g r e s s w i t h it t h e y s h o u l d first e x a m i n e their o w n m e n t a l p o w e r s . T h e task that L o c k e t h e n set h i m s e l f w a s to s e e w h a t s u b j e c t s t h e h u m a n u n d e r s t a n d i n g w a s or w a s n o t fitted to d e a l w i t h . In t h e I n t r o d u c t i o n h e t h e n w r i t e s in similar spirit, t h u s : This was that which gave the first rise to this Essay concerning the understanding. For I thought that the first step towards satisfying several inquiries the mind of man was very apt to run into was to take a survey of our own understandings, examine our own powers, and see to what things they were adapted. T h e p r o j e c t , as I s e e it, w a s to a t t e m p t t o settle d i s p u t e s c o n c e r n i n g t h e e x t e n t of h u m a n k n o w l e d g e b y first p r o v i d i n g a n o u t l i n e o f t h e faculties of t h e h u m a n m i n d , a n d of t h e m i n d ' s

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n a t u r a l m o d e s of a c c e s s to t h e w o r l d , a n d t h e n to r e g a r d k n o w l e d g e - c l a i m s a s c o n s t r a i n e d to b e c o n s i s t e n t w i t h t h a t a c c o u n t . T h i s is p r e c i s e l y w h a t I a m m a i n t a i n i n g is t h e c o r e empiricist c o m m i t m e n t . (A p r o b l e m for this r e a d i n g of L o c k e ' s p r o j e c t is that it h a s s e e m e d to m a n y c o m m e n t a t o r s that t h e n a t u r a l i s m , a n d r e j e c t i o n of n a t i v i s m , of t h e Essay a r e i n c o n s i s t e n t w i t h t h e d o c t r i n e of N a t u r a l L a w that lies at t h e c e n t r e of L o c k e ' s Two Treatises of Government. For e x a m p l e , at o n e p o i n t in t h e latter h e s p e a k s of Natural L a w a s b e i n g ' w r i t t e n in the h e a r t s of all m a n k i n d ' , a n d certainly G o d p l a y s a crucial role in L o c k e ' s moral s y s t e m a s a w h o l e . N o w o n e r e s p o n s e to this w o u l d b e to c o n c e d e that the t w o w o r k s are i n d e e d i n c o n s i s t e n t , p e r h a p s a p p e a l i n g to L o c k e ' s i n c h o a t e p e r c e p t i o n that t h e y a r e to explain w h y h e w a s s o i n s i s t e n t that t h e Two Treatises b e p u b l i s h e d a n o n y m o u s l y . B u t , in fact, L o c k e ' s c o n s i d e r e d v i e w w a s not that the p r i n c i p l e s of N a t u r a l L a w a r e i n n a t e , b u t r a t h e r that t h e y m a y b e k n o w n by all m a n k i n d t h r o u g h t h e n a t u r a l u s e of r e a s o n . Similarly, he t h o u g h t that w e m a y arrive at k n o w l e d g e of G o d b y m e a n s of rational r e f l e c t i o n o n o b s e r v e d facts a b o u t t h e w o r l d . I n d e e d , L o c k e ' s p r o j e c t t h r o u g h o u t w a s to s h o w that h u m a n k n o w l e d g e — w h e t h e r of s c i e n c e , o r of t h e o l o g y , or of m o r a l s — i s a natural p h e n o m e n o n , a r i s i n g f r o m t h e a p p l i c a t i o n of o u r r e a s o n to t h e data g i v e n to u s in experience. ) 5

6

Similarly H u m e , in d e s c r i b i n g t h e m a i n a i m of his w o r k in t h e I n t r o d u c t i o n to t h e Treatise, a r g u e s that t h e r e is a s e n s e in w h i c h t h e s c i e n c e of h u m a n n a t u r e lies at t h e f o u n d a t i o n of all t h e s c i e n c e s , a n d that w e m a y h o p e to m a k e p r o g e s s w i t h t h e latter b y s t u d y i n g t h e f o r m e r first. N o w h e c a n h a r d l y h a v e m e a n t (can h e ? ) that w e s h o u l d e x p e c t particular d i s c o v e r i e s in p h y s i c s or c h e m i s t r y to b e c o n s e q u e n t o n a d v a n c e s in p s y c h o l o g y . R a t h e r , h e is m o r e p l a u s i b l y r e a d a s s a y i n g that c l a i m s to k n o w l e d g e , in g e n e r a l , h a v e to b e r e n d e r e d c o n s i s t e n t w i t h t h e p o w e r s of m i n d a s c r i b e d to u s b y o u r b e s t p s y c h o l o g i c a l t h e o r i e s — w h i c h is a g a i n t h e c o r e e m p i r i c i s t c o m m i t m e n t . E v e n 5

S e e Two Treatises,

n, s e c t . 1 1 .

T h i s is s h o w n c o n v i n c i n g l y b y S t e p h e n B u c k l e , Natural Law and the Theory of Property ( O x f o r d : O x f o r d U n i v e r s i t y P r e s s , 1 9 9 1 ) , c h . 3 , w h o d r a w s h e a v i l y o n L o c k e ' s Essays on the Law of Nature. 6

Powers of Mind m o r e explicitly, in t h e o p e n i n g s e c t i o n of t h e Enquiry Human Understanding H u m e w r i t e s :

135 Concerning

The only method of freeing learning, at once, from these abstruse questions [of metaphysics], is to enquire seriously into the nature of human understanding, and show, from an exact analysis of its powers and capacity, that it is by no means fitted for such remote and abstruse subjects. H e r e a g a i n t h e p r o j e c t is t h e c o r e e m p i r i c i s t o n e , to c o n s t r a i n k n o w l e d g e - c l a i m s by o u r b e s t t h e o r i e s of the m i n d ' s natural m o d e s of a c c e s s to r e a l i t y . 7

N o t i c e that o n t h e a c c o u n t b e i n g p r o p o s e d h e r e , t h e traditional e m p i r i c i s t i n s i s t e n c e that all k n o w l e d g e m u s t b e g r o u n d e d in e x p e r i e n c e t u r n s o u t n o t to b e l o n g to t h e f o u n d a t i o n s of e m p i r i c i s m a s s u c h . R a t h e r , t h e early e m p i r i c i s t s s t r e s s e d t h e role of e x p e r i e n c e in t h e a c q u i s i t i o n of k n o w l e d g e b e c a u s e e x p e r i e n c e w a s t h e o n l y b e l i e f - a c q u i s i t i o n p r o c e s s of w h i c h t h e y c o u l d b e g i n to give a naturalistic a c c o u n t . S o m y p r o p o s a l n o t o n l y u n i f i e s t h e e m p i r i c i s t o p p o s i t i o n to n a t i v i s m a n d to t h e s u b s t a n t i v e a priori, b u t a l s o s e e s t h e s e a s f l o w i n g from the s a m e underlying c o m m i t m e n t as does the empiricist l a u d i n g of e x p e r i e n c e .

Should w e be Empiricists? L e t u s n o w a s k w h e t h e r t h e p r i n c i p l e of c h a r i t y , a s w e l l a s t e x t u a l fidelity (broadly c o n s t r u e d ) , f a v o u r s m y i n t e r p r e t a t i o n of t h e b a s i s of t h e e m p i r i c i s t tradition. P u t d i f f e r e n t l y , this is to a s k w h e t h e r w e h a v e a n y p o w e r f u l r e a s o n s for t h i n k i n g t h a t knowledge-claims should only be endorsed where w e can p r o v i d e s o m e sort of naturalistic a c c o u n t of t h e r e l e v a n t beliefa c q u i s i t i o n p r o c e s s . W h i c h is a s m u c h a s to s a y : s h o u l d w e , t o d a y , b e e m p i r i c i s t s ( g i v e n m y p r o p o s e d a c c o u n t of t h e c o r e of N o t e h o w t h e a b o v e q u o t a t i o n s f r o m L o c k e a n d H u m e s e e m to e c h o t h e C r i t i c a l P h i l o s o p h y o f K a n t . Y e t t h e w a y in w h i c h K a n t t a k e s u p t h e e m p i r i c i s t c h a l l e n g e — w h i c h is t o e x p l a i n h o w r e a s o n c a n h a v e t h e p o w e r t o g e n e r a t e s u b s t a n t i v e k n o w l e d g e — i s n o t a n a t u r a l i s t i c o n e . It is r a t h e r t o c l a i m t h a t t h e b a s i c s t r u c t u r e o f t h e w o r l d , a s o b j e c t o f o u r e x p e r i e n c e , is d e t e r m i n e d b y t h e s u b j e c t i v e c o n s t i t u t i o n o f t h e h u m a n m i n d . H e a l s o differs in t h i n k i n g t h a t w e c a n h a v e a c c e s s t o this c o n s t i t u t i o n a p r i o r i . F o r s o m e f u r t h e r d i s c u s s i o n , s e e t h e final s e c t i o n o f c h a p t e r 1 0 . 7

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e m p i r i c i s m ) ? Part of t h e p o i n t of a s k i n g this q u e s t i o n is t h a t it will e n a b l e u s to a p p r o a c h t h e i s s u e of w h a t motivates w h a t I a m calling t h e c o r e e m p i r i c i s t c o m m i t m e n t . W h y w o u l d a n y o n e w a n t to c o n s t r a i n k n o w l e d g e - c l a i m s by o u r b e s t p s y c h o l o g i c a l theories? O n e line of t h o u g h t is that n o t o n l y is m y c o n s t r u a l of e m p i r i c i s m c o n s i s t e n t with a reliabilist t h e o r y of k n o w l e d g e , as I a r g u e d a b o v e , b u t that it m a y actually b e e n t a i l e d by s u c h a t h e o r y . For w h e n w e d o e p i s t e m o l o g y w e w a n t to k n o w w h a t w e can k n o w . T h i s m e a n s , for t h e reliabilist, that w e w a n t to k n o w w h i c h beliefs or b e l i e f - t y p e s a r e c a u s e d by reliable p r o c e s s e s . But a p r o c e s s that l e a d s u s to form b e l i e f s i n c o n s i s t e n t with o u r o t h e r beliefs c a n n o t in g e n e r a l b e reliable, if w e s u p p o s e that o u r beliefs are on t h e w h o l e t r u e . S o a b e l i e f in t h e reliable a c q u i s i t i o n of o n e o f o u r first-order beliefs will n o t itself b e reliably a c q u i r e d ( n o r c o n s t i t u t e s e c o n d - o r d e r k n o w l e d g e ) if it conflicts with o u r o t h e r b e l i e f s , i n c l u d i n g t h o s e of s c i e n c e . T h i s then s u g g e s t s that w e can o n l y k n o w that w e h a v e k n o w l e d g e of s o m e t h i n g , if w e can p r o v i d e at least t h e b e g i n n i n g s of a scientific a c c o u n t of how w e k n o w that t h i n g — w h i c h is precisely e m p i r i c i s m ' s b a s i c d e m a n d . It m i g h t b e o b j e c t e d that it is o n e t h i n g to say that m y b e l i e f in t h e reliability of a g i v e n belief-acquisition p r o c e s s is n o t in conflict with m y scientific b e l i e f s , a n d quite a n o t h e r to s a y t h a t I m u s t t h e r e f o r e b e able to p r o v i d e a scientific a c c o u n t of t h a t p r o c e s s . F o r surely a belief can b e c o n s i s t e n t w i t h a b o d y of scientific t h e o r y w i t h o u t b e i n g e x p l i c a b l e in t e r m s of it. T h e a b s e n c e of conflict m i g h t p l a u s i b l y b e t h o u g h t to b e r e q u i r e d b y reliabilism. But it is t h e d e m a n d for scientific explicability that c o n s t i t u t e s the c o r e of e m p i r i c i s m , o n m y a c c o u n t , a n d that w e are n o w a t t e m p t i n g to j u s t i f y . The distance between these two requirements may, however, b e s m a l l e r t h a n it a p p e a r s . F o r recall that t h e e m p i r i c i s t is i n s i s t i n g o n l y o n t h e beginnings of a naturalistic a c c o u n t of t h e r e l e v a n t b e l i e f - a c q u i s i t i o n p r o c e s s . It m a y t h e n b e that in m a n y c a s e s , at least, t h e r e a s o n w h y w e c a n n o t p r o v i d e e v e n t h e b e g i n n i n g s of s u c h a n a c c o u n t is that c u r r e n t scientific t h e o r y s t r o n g l y s u g g e s t s that t h e r e is no such process. So while reliabilism m a y n o t in itself entail t h e e m p i r i c i s t c o n s t r a i n t o n k n o w l e d g e - c l a i m s , it will d o s o w h e n p u t t o g e t h e r w i t h t h e

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t h e s i s that c u r r e n t s c i e n c e d o e s n o t r e c o g n i z e t h e e x i s t e n c e of t h e b e l i e f - a c q u i s i t i o n p r o c e s s in q u e s t i o n . B u t c a n it really b e r e a s o n a b l e to d e n y that w e h a v e k n o w l e d g e of s o m e s u b j e c t - m a t t e r , m e r e l y b e c a u s e o u r p r e s e n t scientific b e l i e f s p r o v i d e u s w i t h n o m a t e r i a l s w i t h w h i c h to f r a m e a r e m o t e l y p l a u s i b l e a c c o u n t of h o w w e m i g h t h a v e a c q u i r e d that k n o w l e d g e ? L e t u s c o n s i d e r a n e x a m p l e in s o m e detail, as a test c a s e . S u p p o s e that s o m e p e r s o n , or g r o u p of p e r s o n s , c l a i m s to b e prescient. T h a t is to s a y , t h e y claim to h a v e intuitive ( n o n - i n f e r e n t i a l ) k n o w l e d g e of t h e f u t u r e . O f c o u r s e m a n y p e o p l e h a v e actually m a d e s u c h c l a i m s , b u t let u s i m a g i n e an e x a m p l e in w h i c h it s e e m s i n d i s p u t a b l e that t h e p r e d i c t i o n s v e r y o f t e n turn out right. S o t h e s e p e o p l e a p p a r e n t l y h a v e true beliefs a b o u t t h e f u t u r e that a r e n o t arrived at by i n f e r e n c e f r o m c u r r e n t t e n d e n c i e s . T h e q u e s t i o n , t h e n , is w h e t h e r w e c a n give s o m e a c c o u n t of t h e p r o c e s s b y w h i c h t h o s e b e l i e f s are a c q u i r e d ; a n d , if n o t , w h e t h e r w e a r e j u s t i f i e d in d e n y i n g that t h e s e p e o p l e m a y b e said to h a v e k n o w l e d g e of t h e f u t u r e . I c a n t h i n k of at least t h r e e h y p o t h e s e s that a n e m p i r i c i s t m i g h t p r o p o s e , in o r d e r to a c c o u n t for all t h o s e c a s e s of t h e a p p a r e n t p h e n o m e n o n o f p r e s c i e n c e that h a v e actually o c c u r r e d . First, it m i g h t b e s u g g e s t e d that t h e p e o p l e in q u e s t i o n a r e p r e d i c t i n g t h e f u t u r e on t h e b a s i s of a non-conscious i n f e r e n c e f r o m their k n o w l e d g e of c u r r e n t t e n d e n c i e s , in w h i c h c a s e t h e r e w o u l d b e n o t h i n g m y s t e r i o u s a b o u t their p o w e r s . B u t this m a y turn o u t n o t to b e t h e c a s e . F o r w e c a n easily i m a g i n e that t h e y m a y b e able to predict f u t u r e e v e n t s that c o u l d n o t p o s s i b l y h a v e been deduced from current tendencies, such as the accidental d e a t h of a particular p e r s o n in a car c r a s h in t w o y e a r s ' t i m e , p e r h a p s a l s o p r e d i c t i n g t h e d a t e a n d p l a c e of t h e e v e n t . S e c o n d l y , t h e r e is t h e possibility of f r a u d . It m a y b e s u g g e s t e d that t h o s e w h o c l a i m p r e s c i e n c e a r e covertly b r i n g i n g a b o u t , t h e m s e l v e s , t h e e v e n t s t h a t t h e y p r e d i c t . B u t a g a i n this m i g h t c o n c e i v a b l y b e r u l e d o u t , e i t h e r b e c a u s e t h e e v e n t s in q u e s t i o n a r e b e y o n d t h e c a u s a l p o w e r s of a n y i n d i v i d u a l or g r o u p of i n d i v i d u a l s ( s u c h as t h e a p p e a r a n c e of a n e w c o m e t in t h e s k y o n a particular d a t e ) , or b e c a u s e w e t a k e s t e p s to e n s u r e that those w h o m a k e the predictions have n o opportunity to i n t e r f e r e w i t h t h e c o u r s e of e v e n t s , p e r h a p s b y i m p r i s o n i n g them.

138

Powers of Mind

It m i g h t finally b e s u g g e s t e d that t h e p r e d i c t i o n s a r e f r a m e d w i t h s u f f i c i e n t v a g u e n e s s to g i v e m e r e l y t h e illusion of a c c u r a c y . T h i s idea is a l r e a d y familiar f r o m a s t r o l o g y , w h i c h p u r p o r t s to p r e d i c t f e a t u r e s of p e o p l e ' s c h a r a c t e r a n d life h i s t o r y f r o m t h e d i s t r i b u t i o n of t h e p l a n e t s at t h e t i m e of their birth. For p r o v i d e d that t h e p r e d i c t i o n s a r e sufficiently v a g u e a n d g e n e r a l , a n d c o n c e r n t o p i c s that p e o p l e w a n t v e r y m u c h to h e a r a b o u t , a n d that o c c u r fairly c o m m o n l y , t h e r e is a g o o d c h a n c e that t h o s e p r e d i c t i o n s will c o m e to be r e g a r d e d as h a v i n g b e e n fulfilled. (If y o u r h o r o s c o p e for t h e w e e k s a y s ' P e r s o n a l r e l a t i o n s h i p s r u n s m o o t h l y ' , y o u m a y , if y o u a r e i n c l i n e d , r e g a r d it a s verified b y t h e fact that you get on well with y o u r lover all w e e k , i g n o r i n g t h e fact that if it had said the o p p o s i t e y o u w o u l d equally h a v e r e g a r d e d that a s t r u e , in t h e light of t h e r o w y o u h a d w i t h y o u r m o t h e r on t h e W e d n e s d a y . ) A n e m p i r i c i s t c o u l d s u g g e s t that s o m e t h i n g similar m a y also b e t a k i n g p l a c e in o u r i m a g i n e d c a s e of p r e s c i e n c e . B u t a g a i n it m a y turn o u t n o t to b e s o . For t h e p r e d i c t i o n s in q u e s t i o n m a y be q u i t e p r e c i s e , c o n c e r n i n g m a t t e r s that are p e r h a p s u n u s u a l , a n d of n o particular h u m a n i n t e r e s t . It w o u l d t h e n b e h a r d to s e e h o w o u r i m p r e s s i o n of s u c c e s s c o u l d b e illusory. If a s i t u a t i o n of this sort w e r e to o c c u r , it w o u l d b e a s e r i o u s e m b a r r a s s m e n t to an e m p i r i c i s t , g i v e n m y c h a r a c t e r i z a t i o n of their p o s i t i o n . F o r w e h a v e not t h e faintest idea h o w t h e r e c a n b e a reliable p r o c e s s for a c q u i r i n g true b e l i e f s a b o u t t h e f u t u r e , e x c e p t by i n f e r e n c e f r o m c u r r e n t t e n d e n c i e s . F o r h o w c o u l d a f u t u r e e v e n t e x e r t a n y k i n d of i n f l u e n c e on t h e h u m a n m i n d ? H o w c o u l d t h e m e r e fact that a n e v e n t will t a k e p l a c e at a p a r t i c u l a r t i m e in t h e f u t u r e give rise to a n y p r o c e s s b r i n g i n g s o m e o n e to b e l i e v e that it will? T h e i d e a s e e m s barely intelligible. Y e t , in t h e e x a m p l e a b o v e , w e w o u l d h a v e p o w e r f u l r e a s o n s for t h i n k i n g that t h e s e p e o p l e d o h a v e k n o w l e d g e of t h e f u t u r e , b a s e d u p o n their p a s t s u c c e s s . S o , in s u c h a c a s e , w e c o u l d k n o w t h a t t h e y h a v e k n o w l e d g e , h a v i n g e v e r y r e a s o n to t h i n k t h a t t h e i r b e l i e f s a b o u t t h e f u t u r e are in fact p r o d u c e d t h r o u g h a p r o c e s s that is r e l i a b l e , a l t h o u g h w e c a n n o t e v e n b e g i n to g i v e a n a c c o u n t of t h e n a t u r e o f t h a t p r o c e s s . N o w in o n e r e s p e c t this e x a m p l e p r o v i d e s a t o u g h e r o p p o n e n t t h a n e m p i r i c i s m h a s traditionally f a c e d . T h i s is b e c a u s e t h e r e is n o o b v i o u s w a y of r e i n t e r p r e t i n g t h e c o n t e n t of t h e

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b e l i e f s in q u e s t i o n s o as to r e n d e r their m o d e of a c q u i s i t i o n l e s s p r o b l e m a t i c . In c o n n e c t i o n w i t h logic a n d m a t h e m a t i c s , in c o n t r a s t , o n e s t a n d a r d e m p i r i c i s t m o v e h a s b e e n to d e n y that w e a r e f o r c e d to i n t e r p r e t t h e p r o p o s i t i o n s in q u e s t i o n a s b e i n g c o n c e r n e d w i t h a m i n d - i n d e p e n d e n t r e a l m of a b s t r a c t o b j e c t s . If w e can rather construe such propositions as being concerned w i t h m e n t a l c o n s t r u c t i o n s of o n e sort o r a n o t h e r , t h e n t h e r e will b e n o special p r o b l e m in e x p l a i n i n g h o w t h e r e c a n b e n a t u r a l p r o c e s s e s that lead u s to h a v e k n o w l e d g e of their t r u t h . In t h e c a s e of p r o p o s i t i o n s a b o u t t h e f u t u r e , on t h e o t h e r h a n d , n o s u c h r e i n t e r p r e t a t i o n is a v a i l a b l e . W e c o u l d t h e r e f o r e p u t f o r w a r d a w e a k e r v e r s i o n of t h e p r o p o s e d c o r e of e m p i r i c i s m , w h i c h m i g h t e n a b l e u s to d i s t i n g u i s h b e t w e e n p r e s c i e n c e on t h e o n e h a n d , a n d t h e v a r i o u s f o r m s of p l a t o n i s m on t h e o t h e r . W e could say that n o c l a i m s to k n o w l e d g e s h o u l d b e g r a n t e d w h e r e w e c a n n o t b e g i n to give a n a t u r a l a c c o u n t o f t h e p r o c e s s t h r o u g h w h i c h w e a c q u i r e that k n o w l e d g e , unless the e v i d e n c e for the e x i s t e n c e of s o m e sort of reliable p r o c e s s is o v e r w h e l m i n g , a n d unless t h e r e is n o possibility of r e i n t e r p r e t i n g t h e c o n t e n t of t h e b e l i e f s in q u e s t i o n in s u c h a w a y as to r e n d e r their m o d e of a c q u i s i t i o n less p r o b l e m a t i c . S o in t h e e n d (if s u f f i c i e n t e v i d e n c e o f t h e sort d e s c r i b e d a b o v e w e r e to e m e r g e ) w e m a y h a v e n o c h o i c e b u t to a c c e p t that w e c a n h a v e k n o w l e d g e of t h e f u t u r e t h r o u g h p r e s c i e n c e , e v e n t h o u g h w e c a n n o t b e g i n t o a c c o u n t for t h e mechanism involved.

The A d e q u a c y of Science In fact w e m a y also r e s p o n d t o t h e e x a m p l e of p r e s c i e n c e m o r e directly. W e c a n insist that it is m e r e l y i m a g i n a r y , a n d that a g e n u i n e c a s e of p r e s c i e n c e will n e v e r really o c c u r . F o r t h e e m p i r i c i s t n e e d n o t b e c l a i m i n g to k n o w a priori t h a t all k n o w l e d g e m u s t arise t h r o u g h n a t u r a l p r o c e s s e s , of w h i c h w e c a n in p r i n c i p l e p r o v i d e a n a c c o u n t . R a t h e r , their a t t i t u d e s h o u l d b e s e e n as r e s u l t i n g f r o m a m o r e g e n e r a l c o m m i t m e n t to t h e u l t i m a t e (or at l e a s t in p r i n c i p l e ) explicability of all n a t u r a l p h e n o m e n a , i n c l u d i n g that o f b e l i e f a c q u i s i t i o n . T h i s c o m m i t m e n t m a y b e s u p p o s e d to r e c e i v e its j u s t i f i c a t i o n f r o m p a s t

140

Powers of Mind

scientific s u c c e s s . A n e m p i r i c i s t m a y t h e r e f o r e r e s p o n d to o u r e x a m p l e b y s a y i n g that t h e y a r e p r e p a r e d to b e t that a g e n u i n e c a s e of p r e s c i e n c e will n e v e r in fact o c c u r — p r e c i s e l y b e c a u s e w e c a n n o t b e g i n to s e e h o w t h e r e c o u l d b e a n y n a t u r a l p r o c e s s u n d e r l y i n g t h e a c q u i s i t i o n of o u r beliefs in s u c h a c a s e . It m a y be o b j e c t e d that e m p i r i c i s t s , as s u c h , c a n n o t b e c o m m i t t e d to t h e t h e s i s that all p r o c e s s e s in n a t u r e are in principle e x p l i c a b l e by s c i e n c e , h a p p e n i n g in a c c o r d a n c e w i t h causal l a w . For L o c k e , for o n e , b e l i e v e d that t h e r e a r e n a t u r a l p r o c e s s e s — p a r t i c u l a r l y t h o s e c o n n e c t i n g p h y s i c a l e v e n t s in o u r b o d i e s with i d e a s in o u r m i n d s — t h a t m u s t f o r e v e r o u t s t r i p o u r p o w e r s of e x p l a n a t i o n . But t h e r e are t w o p o i n t s to b e m a d e in r e p l y . T h e first is that L o c k e w a s u n d u l y sceptical a b o u t o u r abilities to d i s c o v e r the h i d d e n p r o c e s s e s at w o r k in n a t u r e , as s u b s e q u e n t scientific a d v a n c e h a s s h o w n . T h e s e c o n d , a n d m o r e i m p o r t a n t , is that h e w a s w o r k i n g with a m u c h m o r e d e m a n d i n g c o n c e p t of e x p l a n a t i o n t h a n that p r e s u p p o s e d h e r e . In L o c k e ' s v i e w , c o n n e c t i o n s b e t w e e n e v e n t s will o n l y c o u n t a s h a v i n g b e e n explained if t h e y h a v e b e e n m a d e fully a n d rationally intelligible to u s . H e m i g h t t h e n h a v e b e e n h a p p y to a g r e e that all p r o c e s s e s in n a t u r e o c c u r in a c c o r d a n c e with c a u s a l l a w s that a r e in p r i n c i p l e d i s c o v e r a b l e , e v e n t h o u g h a p p e a l to t h e s e l a w s c a n n e v e r m a k e e v e n t s intelligible in t h e w a y that ' A n y t h i n g red is c o l o u r e d ' is intelligible. 8

L o o k e d at in t h e w a y I a m s u g g e s t i n g , e m p i r i c i s t c o n s t r a i n t s on k n o w l e d g e - c l a i m s m a y be s e e n to s t e m f r o m a m o r e g e n e r a l belief in the u l t i m a t e a d e q u a c y of s c i e n c e . T h e s e q u e n c e of t h o u g h t w o u l d b e this: if w e w e r e to p o s s e s s k n o w l e d g e of t h e m a t t e r in q u e s t i o n (the f u t u r e , s a y ) , t h e n o u r b e l i e f s w o u l d h a v e to be c a u s e d by a reliable p r o c e s s ; b u t if o u r c u r r e n t s c i e n c e is s u c h that w e c a n n o t e v e n b e g i n to f r a m e a h y p o t h e s i s as to w h a t that p r o c e s s m i g h t b e , t h e n this in itself p r o v i d e s u s w i t h g o o d r e a s o n for d o u b t i n g its e x i s t e n c e . A n a n a l o g y m a y h e l p h e r e . S u p p o s e s o m e o n e s u g g e s t s that z e b r a s in t h e w i l d p u t o n o v e r c o a t s at n i g h t to k e e p w a r m . A r e w e n o t p r e p a r e d t o b e t , i n t h e light of o u r c u r r e n t k n o w l e d g e , that this will n e v e r t u r n o u t to b e t r u e ? I n d e e d , if s o m e o n e w e r e 9

S e e t h e Essay, b k . iv, c h . in. I h a v e lifted this e x a m p l e f r o m D a n i e l D e n n e t t ' s Brainstorms H a r v e s t e r , 1 9 7 8 ) , t h o u g h h e u s e s it f o r q u i t e a n o t h e r p u r p o s e . 8 9

(Brighton:

Powers of Mind

141

to p r e s e n t e v i d e n c e of its t r u t h , s h o u l d w e n o t d o o u r b e s t to d i s m i s s or e x p l a i n t h a t e v i d e n c e a w a y ? F o r if it were t r u e , it would apparently be wholly inexplicable. Are w e to imagine that z e b r a s h a v e their o w n s e c r e t t e c h n o l o g y , w h i c h e n a b l e s t h e m to w e a v e c l o t h ? O r that t h e y h a v e a n e l a b o r a t e a n d s o far u n d i s c o v e r e d s y s t e m for s t e a l i n g o v e r c o a t s f r o m h u m a n b e i n g s ? T h e s e i d e a s p a s s b e y o n d t h e possibility of belief, g i v e n w h a t w e a l r e a d y k n o w a b o u t z e b r a s a n d their h a b i t a t . Similarly, I s u g g e s t , w i t h o u r i m a g i n e d c a s e of p r e s c i e n c e : g i v e n w h a t w e a l r e a d y k n o w a b o u t t h e w o r l d , w e m a y b e s u r e that it will n e v e r happen. T h i s is n o t to say that t h e e m p i r i c i s t c o n s t r a i n t on k n o w l e d g e claims is an infallible o n e . Plainly it c a n n o t b e , s i n c e it led t h e early e m p i r i c i s t s to d e n y t h e truth of n a t i v i s m — a s it t u r n s o u t , i n c o r r e c t l y . It m a y n e v e r t h e l e s s b e a r e a s o n a b l e o n e . If w e s h a r e t h e e m p i r i c i s t belief in t h e u l t i m a t e e x p l a n a t o r y a d e q u a c y o f s c i e n c e (or at least their belief that all p r o c e s s e s in n a t u r e a r e natural o n e s , h a p p e n i n g in a c c o r d a n c e with c a u s a l l a w ) , t h e n w e shall d e n y that t h e r e a r e a n y n a t u r a l p h e n o m e n a for w h i c h t h e r e is n o n a t u r a l e x p l a n a t i o n . W e t h e r e f o r e h a v e r e a s o n t o d e n y that s o m e s u g g e s t e d p h e n o m e n o n will e v e r in fact o c c u r , if to t h e b e s t of o u r belief t h e r e c a n b e n o natural e x p l a n a t i o n of it. I n t o this c a t e g o r y , in m y v i e w , fall n o t o n l y c l a i m s of p r e s c i e n c e , b u t also a s t r o l o g y , m a g i c , a n d v a r i o u s a l l e g e d psychic phenomena. W e a r e n o w in a p o s i t i o n to articulate t h e u n d e r l y i n g m o t i v a t i o n b e h i n d t h e c o r e of e m p i r i c i s m . It c o n s i s t s , first, in t h e s e a r c h for a n e x p l a n a t o r y c o h e r e n c e w i t h i n t h e overall s y s t e m of o u r b e l i e f s ; a n d , s e c o n d l y , in a c o m m i t m e n t to t h e e x p l a n a t o r y a d e q u a c y of s c i e n c e . T h e first of t h e s e s t r a n d s l e a d s e m p i r i c i s t s to try to m a k e o u r first-order beliefs a b o u t t h e w o r l d c o h e r e w i t h o u r b e s t t h e o r y of t h e h u m a n m i n d a n d its p o w e r s , w h e r e n e c e s s a r y ( a n d if p o s s i b l e ) r e i n t e r p r e t i n g t h e s u b j e c t m a t t e r s of t h o s e b e l i e f s to r e n d e r t h e m m o r e a c c e s s i b l e to t h e h u m a n m i n d . T h e s e c o n d s t r a n d l e a d s t h e m to r e j e c t c l a i m s to k n o w l e d g e w h e r e w e c a n n o t e v e n b e g i n to c o n s t r u c t a p l a u s i b l e naturalistic e x p l a n a t i o n of t h e m a n n e r in w h i c h that k n o w l e d g e might have b e e n acquired. Both strands are, n o w , eminently r e a s o n a b l e . It is o b v i o u s t h a t w e s h o u l d try to w e l d o u r b e l i e f s i n t o a c o h e r e n t s y s t e m if w e c a n ( m o r e o n this in c h a p t e r 1 2 ) .

142

Powers of Mind

A n d t h e early e m p i r i c i s t s ' m e t h o d o l o g i c a l c o m m i t m e n t to t h e e x p l a n a t o r y a d e q u a c y of s c i e n c e h a s b e e n a m p l y v i n d i c a t e d b y s u b s e q u e n t scientific p r o g r e s s . H o w e v e r , that we are justified in b e l i e v i n g in t h e e x p l a n a t o r y a d e q u a c y of s c i e n c e , g i v e n t h e h u g e s u c c e s s o f s c i e n c e , d o e s n o t m e a n that t h e s a m e c a n b e said o f t h e early e m p i r i c i s t s . O n t h e c o n t r a r y . W h i l e their c o m m i t m e n t to s c i e n c e w a s n o t a m a t t e r of blind faith, s i n c e n o t a b l e a d v a n c e s in k n o w l e d g e h a d a l r e a d y b e e n a c h i e v e d , it w a s n o t fully justified e i t h e r . S o h e r e m a y b e a f u r t h e r r e a s o n w h y t h e early e m p i r i c i s t s did n o t m a k e clear t h e true n a t u r e of their o p p o s i t i o n to n a t i v i s m . F o r , h a d t h e y d o n e s o , t h e y w o u l d h a v e h a d to a d m i t that their p o s i t i o n w a s a l m o s t a s reliant u p o n faith as that of their theistic o p p o n e n t s . It a p p e a r s that m y p r o p o s a l c o n c e r n i n g t h e c o r e of e m p i r i c i s m can i n d e e d b e s u p p o r t e d by c o n s i d e r a t i o n s of c h a r i t y . If w e c a n n o t e v e n b e g i n to give an a c c o u n t of t h e p r o c e s s t h r o u g h w h i c h w e m i g h t h a v e a c q u i r e d a set of b e l i e f s , let a l o n e an a c c o u n t that s h o w s t h e p r o c e s s to b e a reliable o n e , t h e n it is s u r e l y o n l y r e a s o n a b l e that w e s h o u l d refrain f r o m c o m m i t t i n g o u r s e l v e s to t h o s e beliefs if w e c a n p o s s i b l y d o s o . A n d if w e c a n n o t avoid t h e c o n c l u s i o n t h a t t h e b e l i e f s in q u e s t i o n are t r u e o n e s , t h e n w e s h o u l d , if w e c a n , p r o v i d e a n i n t e r p r e t a t i o n of their c o n t e n t that w o u l d r e n d e r their m o d e of a c q u i s i t i o n l e s s p r o b l e m a t i c . T h i s is, I s u g g e s t , p r e c i s e l y w h a t t h e e m p i r i c i s t maintains. N o w , if I a m c o r r e c t in m y c h a r a c t e r i s a t i o n of t h e c o r e o f e m p i r i c i s m , it f o l l o w s t h a t c o n t e m p o r a r y e m p i r i c i s t s s h o u l d h a v e n o o b j e c t i o n s to e v o l u t i o n a r y v e r s i o n s of n a t i v i s m . F o r , u n l i k e d i v i n e i n t e r v e n t i o n , t h e s e l e c t i o n of i n n a t e c h a r a c t e r i s t i c s t h r o u g h e v o l u t i o n is certainly a n a t u r a l p r o c e s s . I n d e e d , it is o n e of w h i c h w e n o t o n l y h a v e t h e o u t l i n e of a n a c c o u n t , b u t a welld e v e l o p e d scientific t h e o r y . M o r e o v e r , e v o l u t i o n a r y s e l e c t i o n is v e r y p r o b a b l y a reliable p r o c e s s w h e r e t h e d e t e r m i n i n g of i n n a t e b e l i e f is c o n c e r n e d , if t h e p o i n t s m a d e i n c h a p t e r 8 , c o n c e r n i n g t h e survival v a l u e of true belief, w e r e s o u n d o n e s . A s e m p i r i c i s t s , w e t h e r e f o r e h a v e n o p r i n c i p l e d r e a s o n for d e n y i n g t h e e x i s t e n c e of i n n a t e k n o w l e d g e . S i n c e w e c a n i n d e e d p r o v i d e a n a c c o u n t of t h e p r o c e s s t h r o u g h w h i c h a b e l i e f m i g h t c o m e t o b e innate, the empiricist constraint on knowledge-claims has n o application.

10 Evolutionary Nativism and A Priori Knowledge IN this c h a p t e r I shall c o n s i d e r h o w m u c h r e m a i n s of t h e traditional conflict b e t w e e n e m p i r i c i s m a n d r a t i o n a l i s m , g i v e n m y p r o p o s e d a c c o u n t of t h e c o r e o f the f o r m e r .

N a t i v i s m a n d the A Priori In c h a p t e r 9 I a r g u e d that c o n t e m p o r a r y e m p i r i c i s t s s h o u l d h a v e n o o b j e c t i o n to e v o l u t i o n a r y v e r s i o n s of n a t i v i s m . It follows t h a t t h e y s h o u l d also h a v e n o o b j e c t i o n to s o m e f o r m s of a priori k n o w l e d g e . F o r k n o w l e d g e w h i c h is i n n a t e will at t h e s a m e t i m e b e a priori, at least in t h e s e n s e of n o t h a v i n g b e e n l e a r n e d f r o m e x p e r i e n c e . T h i s is, if correct, a startling result. It m e a n s , n o t o n l y that o n e c a n r e m a i n a n e m p i r i c i s t w h i l e a c c e p t i n g that there are innate information-bearing mental structures, innate c o n c e p t s , a n d i n n a t e k n o w l e d g e , b u t also w h i l e a c c e p t i n g t h e e x i s t e n c e of s u b s t a n t i v e a priori k n o w l e d g e . I n d e e d , y o u m a y b e i n c l i n e d to o b j e c t that this is t o o g o o d to b e t r u e . F o r t h e r e w o u l d a p p e a r to b e a real d a n g e r , n o w , that I h a v e c o n s t r u e d e m p i r i c i s m in s u c h a w a y that t h e d i f f e r e n c e s b e t w e e n e m p i r i c ism and rationalism m a y disappear altogether. F o r e x a m p l e , if it w e r e to t u r n o u t that a n e v o l u t i o n a r y n a t i v i s m c a n p r o v i d e a n a d e q u a t e d e f e n c e of p l a t o n i s m , t h e n o n m y account a contemporary empiricist would probably have no o b j e c t i o n o f p r i n c i p l e to any of t h e traditional rationalist d o c t r i n e s . In fact it w o u l d t u r n o u t that t h e e a r l y e m p i r i c i s t s ' o p p o s i t i o n to r a t i o n a l i s m d e r i v e d e n t i r e l y f r o m t h e p o o r l y d e v e l o p e d state of s c i e n c e at t h e t i m e , in p a r t i c u l a r f r o m t h e a b s e n c e of a n y sort o f t h e o r y of e v o l u t i o n a r y s e l e c t i o n of inherited characteristics. S o m e m i g h t find such a conclusion

144

Evolutionary

Nativism

s o i m p l a u s i b l e a s to w a r r a n t a r e j e c t i o n of m y a c c o u n t of e m p i r i c i s m . O t h e r s , a c c e p t i n g that a c c o u n t , m i g h t take t h e c o n c l u s i o n to m a r k t h e d e m i s e of e m p i r i c i s m as a distinctive m o v e m e n t in p h i l o s o p h y . I shall m a k e n o a t t e m p t to d e c i d e w h i c h of t h e s e r e s p o n s e s m i g h t b e t h e m o r e r e a s o n a b l e , s i n c e I b e l i e v e that m u c h d o e s in fact r e m a i n of traditional d i s p u t e s b e t w e e n e m p i r i c i s t s a n d rationalists, e v e n given m y a c c o u n t of t h e e s s e n t i a l c o n c e r n s of the f o r m e r . If the c o u r s e of e v o l u t i o n h a s p r o v i d e d u s with s u b s t a n t i v e i n n a t e k n o w l e d g e , e i t h e r of o u r o w n p s y c h o l o g y or of o t h e r a s p e c t s of t h e natural w o r l d , t h e n it will at the s a m e time h a v e p r o v i d e d us with s u b s t a n t i v e a priori k n o w l e d g e . It is i m p o r t a n t to realize, h o w e v e r , that the s t a t u s of s u c h k n o w l e d g e a s a priori will be q u i t e d i f f e r e n t from w h a t rationalist p h i l o s o p h e r s h a v e g e n e r a l l y had in m i n d w h e n they h a v e e m p l o y e d the p h r a s e 'a priori k n o w l e d g e ' . In particular, t h e k n o w l e d g e in q u e s t i o n will not h a v e b e e n a c q u i r e d m e r e l y t h r o u g h the t h i n k i n g of it, by a p r o c e s s of r e a s o n i n g a l o n e . I n n a t e a priori k n o w l e d g e of folkp s y c h o l o g y , for e x a m p l e , w o u l d not c o n s i s t of b e l i e f s that can b e d i s c o v e r e d to be true j u s t by t h i n k i n g of their s u b j e c t - m a t t e r ; n o r w o u l d their c o n t e n t be intuitively c e r t a i n . R a t h e r , w e w o u l d find o u r s e l v e s with t h o s e beliefs a l r e a d y ; a n d t h e n , p r o v i d e d that they are b o t h true a n d reliably a c q u i r e d t h r o u g h e v o l u t i o n , this w o u l d b e sufficient to c o n s t i t u t e t h e m a s k n o w l e d g e . H e n c e at least o n e r e m a i n i n g d i f f e r e n c e from traditional r a t i o n a l i s m is that the m o s t plausible c a s e s of i n n a t e k n o w l e d g e for a c o n t e m p o r a r y e m p i r i c i s t will n o t be k n o w a b l e by t h o u g h t a l o n e . A related p o i n t is that t h e q u e s t i o n w h e t h e r a g i v e n belief is a priori, in t h e nativist s e n s e , will n o t itself b e a n a priori o n e . It will r a t h e r b e e m p i r i c a l . For recall o u r r e j e c t i o n of t h e K K t h e s i s (that k n o w l e d g e r e q u i r e s k n o w l e d g e that y o u k n o w ) in c h a p t e r 5. K n o w i n g s o m e t h i n g ( w h e t h e r a priori or n o t ) is o n e t h i n g , k n o w i n g that y o u k n o w it m a y be s o m e t h i n g q u i t e d i f f e r e n t . In t h e c a s e of f o l k - p s y c h o l o g y , for e x a m p l e , if o u r b e l i e f s a r e , as a m a t t e r of fact, b o t h i n n a t e a n d reliably a c q u i r e d t h r o u g h e v o l u t i o n , t h e n t h e y will b e k n o w n a priori (in t h e s e n s e of n o t h a v i n g b e e n l e a r n e d f r o m e x p e r i e n c e ) . But to k n o w their s t a t u s as s u c h will r e q u i r e e m p i r i c a l i n v e s t i g a t i o n , a n d a r g u m e n t f r o m c o n t i n g e n t p r e m i s s e s , s u c h as w e p r o v i d e d i n c h a p t e r 8 . T h i s is 1

I a s s u m e — s u r e l y p l a u s i b l y — t h a t if s o m e o n e i n n a t e l y k n o w s t h e y will n o t a l s o i n n a t e l y b e l i e v e t h a t t h e y k n o w it. 1

something,

Evolutionary

Nativism

145

in stark c o n t r a s t w i t h t h e traditional rationalist c o n c e p t i o n of a priori k n o w l e d g e w h e r e , s i n c e t h e b e l i e f in q u e s t i o n can b e k n o w n to b e true b y t h o u g h t a l o n e , it is o f t e n felt that t h e k n o w l e d g e that w e k n o w it a priori c a n also b e e s t a b l i s h e d by the very same m e t h o d . With these remaining differences between rationalism and my c o n t e m p o r a r y e m p i r i c i s m e s t a b l i s h e d , let u s turn to c o n s i d e r t h o s e d o m a i n s of belief that h a v e traditionally b e e n r e g a r d e d as a priori, s u c h a s m a t h e m a t i c s a n d logic. A n d let u s c o n s i d e r t h e platonist c o n s t r u a l of the s u b j e c t - m a t t e r of t h e s e d i s c i p l i n e s , w h i c h e n t a i l s that o u r k n o w l e d g e of t h e m is not o n l y a priori but g e n u i n e l y s u b s t a n t i v e , b e i n g c o n c e r n e d with a reality i n d e p e n d e n t of o u r m i n d s . O u r q u e s t i o n is g o i n g to b e w h e t h e r an e v o l u t i o n a r y n a t i v i s m can b e p r e s s e d into t h e s e r v i c e of p l a t o n i s m , to p r o v i d e a naturalistic a c c o u n t of h o w the p r o c e s s t h r o u g h w h i c h w e a c q u i r e beliefs a b o u t the abstract realm m a y b e a reliable o n e . But first let u s c o n s i d e r w h a t s u c h a n a t i v i s m m i g h t look like. P e r h a p s the m o s t p l a u s i b l e f o r m of nativistic p l a t o n i s m is that d e f e n d e d b y Jerrold K a t / . . H i s a p p r o a c h c o m b i n e s e v o l u t i o n a r y n a t i v i s m w i t h m o r e traditional a p p e a l s to intuition as a w a r r a n t for o u r a priori k n o w l e d g e of logic a n d m a t h e m a t i c s . T h e a d v a n t a g e of this c o m b i n a t i o n of v i e w s is that it is o b v i o u s l y not t h e c a s e that w e s i m p l y find o u r s e l v e s with m a t h e m a t i c a l b e l i e f s , as is p e r h a p s s o with f o l k - p s y c h o l o g y . A n y a d e q u a t e a c c o u n t of m a t h e m a t i c a l k n o w l e d g e s h o u l d find s o m e p l a c e for t h e c o n c e p t of intuitively a c c e p t a b l e proof of n e w m a t h e m a t i c a l propositions. O n the other h a n d , intuition, without the backing of a rich n a t i v i s m , c a n n o t b e t h o u g h t of as a form of direct a c c e s s to the a b s t r a c t r e a l m , a s w e s a w in c h a p t e r 3. 2

K a t z ' s idea is that w e h a v e a n i n n a t e l y g i v e n faculty of i n t u i t i o n , w h o s e c o n s t i t u e n t s t r u c t u r e m i r r o r s that of t h e a b s t r a c t r e a l m . T h i s faculty e n a b l e s u s to c o n s t r u c t m e n t a l r e p r e s e n t a t i o n s of i t e m s i n t h e a b s t r a c t w o r l d , a n d to intuit, o n this b a s i s , w h a t h a s to b e true a b o u t t h o s e t h i n g s . B u t i n t u i t i o n is n o t to b e t h o u g h t of o n t h e m o d e l of s e n s e - p e r c e p t i o n . H i s c l a i m is n o t that a b s t r a c t o b j e c t s e x e r t a c a u s a l i n f l u e n c e o n o u r m i n d s via t h e faculty of i n t u i t i o n , t h o s e o b j e c t s b e i n g directly r e s p o n s i b l e for o u r b e l i e f s . It is r a t h e r that t h e i n n a t e l y g i v e n s t r u c t u r e of t h e faculty of i n t u i t i o n c a u s e s u s to h a v e true beliefs 2


and Other Abstract

Objects,

ch. 6.

146

Evolutionary

Nativism

a b o u t i t e m s in t h e a b s t r a c t r e a l m , b y d e t e r m i n i n g o u r intuitive j u d g e m e n t s w h e n w e m a n i p u l a t e o u r m e n t a l r e p r e s e n t a t i o n s of t h o s e t h i n g s . O n this a c c o u n t o u r k n o w l e d g e of t h e a b s t r a c t r e a l m is g e n u i n e l y a priori. F o r it is a r r i v e d at b y t h o u g h t a l o n e , this b e i n g t h e o n l y p r o c e s s directly i n v o l v e d in o u r a c q u i s i t i o n of n e w m a t h e m a t i c a l or logical b e l i e f s . O n t h e o t h e r h a n d , t h e i n t u i t i o n s w e arrive at by s u c h t h o u g h t will o n l y b e reliable g u i d e s to t h e w a y t h i n g s a r e in t h e a b s t r a c t r e a l m if t h e s t r u c t u r e o f t h e faculty of i n t u i t i o n h a s b e e n reliably d e t e r m i n e d in e v o l u t i o n . S o t h e k n o w l e d g e that w e k n o w is n o t e q u a l l y a priori. W h a t e m e r g e s f r o m this d i s c u s s i o n of K a t z ' s p l a t o n i s m is t h i s . E v e n if it w e r e to turn o u t that e m p i r i c i s t s c a n n o w a c c e p t t h e e x i s t e n c e of s u b s t a n t i v e k n o w l e d g e o b t a i n a b l e by r e a s o n a l o n e , through accepting s o m e form of evolutionary nativism, they can still m a i n t a i n their traditional o p p o s i t i o n to t h e c h a r a c t e r i s t i c rationalist t h e s i s that w e m a y k n o w , b y r e a s o n a l o n e , that w e are c a p a b l e of o b t a i n i n g s u b s t a n t i v e i n f o r m a t i o n a b o u t t h e w o r l d (or a b o u t o u r s e l v e s ) by r e a s o n a l o n e . F o r t h e y will c o n t i n u e to d e m a n d a naturalistic e x p l a n a t i o n of h o w r e a s o n c a n h a v e a c q u i r e d t h e p o w e r reliably to g e n e r a t e t r u t h s a b o u t t h i n g s o u t s i d e itself. It s e e m s certain that n o a d e q u a t e a n s w e r to this can b e p r o v i d e d , in t u r n , by r e a s o n a l o n e . It will r a t h e r r e q u i r e the b a c k i n g of s o m e e v o l u t i o n a r y ( a n d h e n c e e m p i r i c a l ) e x p l a n a tion, if r e a s o n ' s c l a i m s to k n o w l e d g e a r e to b e a l l o w e d . S o at least o n e f u r t h e r a s p e c t of t h e traditional d e b a t e s b e t w e e n e m p i r i c i s t s a n d rationalists will s u r v i v e m y p r o p o s e d a c c o u n t of t h e c o r e of e m p i r i c i s m . O n l y if o u r a priori k n o w l e d g e c o n c e r n s n o t h i n g that is i n d e p e n d e n t of o u r m i n d s (that is to s a y , o n l y if it is a n a l y t i c ) c a n w e k n o w a priori that w e p o s s e s s s u c h knowledge.

Nativism and M a t h e m a t i c s T h e o n l y i s s u e n o w r e m a i n i n g is w h e t h e r a n e v o l u t i o n a r y n a t i v i s m c a n b e u s e d to r e n d e r a c c e p t a b l e to c o n t e m p o r a r y e m p i r i c i s t s s o m e of t h e p a r t i c u l a r beliefs traditionally d e f e n d e d b y r a t i o n a l i s t s , s u c h as p l a t o n i s m . F o r e x a m p l e , c a n a p l a t o n i s t r e s p o n d to t h e c h a l l e n g e to p r o v i d e a n a t u r a l i s t i c a c c o u n t of t h e

Evolutionary

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p r o c e s s t h r o u g h w h i c h w e a c q u i r e k n o w l e d g e of t h e a b s t r a c t r e a l m , b y m a i n t a i n i n g t h a t s u c h k n o w l e d g e a r i s e s o u t of t h e s t r u c t u r e of a faculty of i n t u i t i o n that h a s b e e n d e t e r m i n e d t h r o u g h e v o l u t i o n a r y s e l e c t i o n ? T h e difficulty for s u c h a c c o u n t s that I p r o p o s e to raise first, r e l a t e s to t h e s u p p o s e d i n n a t e n e s s of o u r k n o w l e d g e of m a t h e m a t i c s ( t h e s u b j e c t - m a t t e r of w h i c h is understood platonistically). H o w c a n it b e m a i n t a i n e d that s u c h k n o w l e d g e is i n n a t e , g i v e n that a d e v e l o p e d f o r m of m a t h e m a t i c s h a s o n l y b e e n in e x i s t e n c e for a f e w t h o u s a n d y e a r s ? F o r it is o b v i o u s l y n o t t h e c a s e that all h u m a n s n o w living a r e d e s c e n d e d from a c o m m o n a n c e s t o r , or s i n g l e g r o u p of a n c e s t o r s , of a f e w t h o u s a n d y e a r s ago. O n the contrary, h u m a n beings were already widely d i s p e r s e d a r o u n d t h e g l o b e at t h e t i m e w h e n m a t h e m a t i c a l k n o w l e d g e first b e g a n to m a k e its a p p e a r a n c e . Y e t t h e r e a p p e a r to b e n o h u m a n b e i n g s w h o lack m a t h e m a t i c a l ability. E v e n t h o s e primitive tribes w h o (until r e c e n t l y ) h a d n o k n o w l e d g e of m a t h e m a t i c s at all ( p e r h a p s c o u n t i n g ' o n e , t w o , t h r e e , m a n y ' ) a r e able to g r a s p it q u i t e easily w h e n i n t r o d u c e d t o t h e i d e a s . S o if m a t h e m a t i c a l k n o w l e d g e is to b e i n n a t e in its o w n r i g h t , it w o u l d h a v e to b e s u p p o s e d that it e v o l v e d s e p a r a t e l y i n all t h e d i f f e r e n t g r o u p s of h u m a n s at a b o u t t h e s a m e t i m e . T h i s is e x t r e m e l y u n l i k e l y , g i v e n that e v o l u t i o n o p e r a t e s b y r a n d o m gene mutation. O n e r e s p o n s e to this p r o b l e m w o u l d b e to s u g g e s t that o u r i n n a t e k n o w l e d g e of m a t h e m a t i c s s h o u l d really b e s u b s u m e d w i t h i n o u r k n o w l e d g e of logic. F o r it is clear t h a t all h u m a n c o m m u n i t i e s , h o w e v e r r e m o t e in t h e p a s t , will h a v e h a d k n o w l e d g e of t h e t r u t h s of logic ( t h o u g h w h e t h e r t h o s e t r u t h s w o u l d c o n c e r n p l a t o n i c o b j e c t s is o f c o u r s e a n o t h e r m a t t e r ) . R a t i o n a l p l a n n i n g of a s t r a t e g y of a c t i o n w o u l d b e i m p o s s i b l e if o n e c o u l d n o t rely u p o n s u c h t r u t h s a s 'If I will n o t g e t A u n l e s s I d o B , a n d I c a n n o t d o B u n l e s s I d o C , t h e n I will n o t g e t A u n l e s s I d o C . It w o u l d b e t e m p t i n g , t h e n , for a p l a t o n i s t to m a i n t a i n that it is t h e logic faculty t h a t is m o s t directly i n n a t e , t h e t r u t h s of m a t h e m a t i c s b e i n g s o m e h o w d e r i v a b l e f r o m t h o s e of logic. T h e c o s t of this r e s p o n s e , h o w e v e r , is t h a t it c o m m i t s u s to t h e logicist p r o g r a m m e of r e d u c i n g m a t h e m a t i c s t o logic, d i s c u s s e d in c h a p t e r 3 . Y e t f e w p h i l o s o p h e r s t o d a y b e l i e v e t h a t such a programme can succeed.

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C h o m s k y , t o o , f a c e s t h e difficulty of e x p l a i n i n g h o w o u r k n o w l e d g e of m a t h e m a t i c s c a n b e i n n a t e , s i n c e h e is a n o t h e r w h o b e l i e v e s that it is s o (but w i t h o u t e n d o r s i n g p l a t o n i s m ) . H i s s o l u t i o n is to s u g g e s t that m a t h e m a t i c s can b e s e e n t o b e at l e a s t partially i n n a t e , by virtue of its similarities w i t h t h e s t r u c t u r e s i n h e r e n t in o u r i n n a t e l a n g u a g e f a c u l t y . In p a r t i c u l a r , t h e g r a m m a r of a n y h u m a n l a n g u a g e will c o n t a i n r u l e s that m a y b e a p p l i e d r e c u r s i v e l y an i n d e f i n i t e n u m b e r of t i m e s . (For e x a m p l e , t h e rule for ' a n d ' e n a b l e s you to reiterate c o n j u n c t i o n s indefinitely: 'A and B and C and D and so on'.) C h o m s k y s u g g e s t s that w e m a y exploit this f e a t u r e of natural l a n g u a g e , which is innately k n o w n , in constructing a s y s t e m of n u m b e r i n g . 3

C a n a p l a t o n i s t , similarly, m a k e u s e of C h o m s k y ' s s u g g e s t ion? I b e l i e v e n o t . For t h e idea is n o t that t h e t r u t h s of m a t h e m a t i c s m a y be reduced to t h o s e of g r a m m a r . T h a t w o u l d b e a b s u r d . R a t h e r , it is that t h e r e is a f o r m a l similarity b e t w e e n t h e t w o , w h i c h can be e x p l o i t e d to e n a b l e u s to c o n s t r u c t the o n e on t h e b a s i s of k n o w l e d g e of t h e o t h e r . But a p l a t o n i s t , of c o u r s e , c a n n o t a c c e p t s u c h an a c c o u n t a s it s t a n d s , s i n c e p l a t o n i s t s d o n o t b e l i e v e that m a t h e m a t i c a l t r u t h s are c o n s t r u c t e d . R a t h e r , t h o s e t r u t h s a r e held to relate to a n o b j e c t i v e a b s t r a c t r e a l m , w h i c h e x i s t s i n d e p e n d e n t l y of o u r m i n d s . S o a p l a t o n i s t w o u l d h a v e to claim that t h e e v o l u t i o n a r y s e l e c t i o n of t h e l a n g u a g e faculty is also reliable in g i v i n g u s k n o w l e d g e of m a t h e m a t i c s , in virtue of the formal similarities b e t w e e n the s t r u c t u r e s of g r a m m a r a n d the s t r u c t u r e of t h e m a t h e m a t i c a l r e a l m . B u t i n fact a m e r e similarity b e t w e e n a r e a l m to w h i c h w e d o h a v e reliable a c c e s s , a n d o n e to w h i c h w e d o n o t , c a n n o t b e sufficient to c o n f e r k n o w l e d g e of t h e latter. For e x a m p l e , m y p e r c e p t i o n s are g e n e r a l l y reliable in giving m e beliefs a b o u t t h e f e a t u r e s of t h e p l a n e t E a r t h . N o w let u s s u p p o s e that t h e r e is a n o t h e r p l a n e t in t h e galaxy that is in fact structurally similar to E a r t h . D o I t h e r e b y h a v e k n o w l e d g e of t h e f e a t u r e s o f that p l a n e t ? O b v i o u s l y n o t , at l e a s t u n t i l I l e a r n o n o t h e r g r o u n d s that the t w o p l a n e t s are i n d e e d similar. E q u a l l y , t h e n , in t h e c a s e of m a t h e m a t i c s : t h e m e r e fact t h a t t h e r e a r e s t r u c t u r a l similarities b e t w e e n t h e m a t h e m a t i c a l r e a l m a n d t h e r u l e s of g r a m m a r c a n n o t b e s u f f i c i e n t for m y i n n a t e k n o w l e d g e of t h e latter to g i v e m e k n o w l e d g e of t h e f o r m e r , 3


and Problems of Knowledge,

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until I k n o w o n o t h e r g r o u n d s t h a t t h e t w o d o m a i n s a r e i n d e e d similar ( a n d in w h a t r e s p e c t s t h e y a r e similar). B u t in o r d e r to k n o w t h i s , of c o u r s e , I s h o u l d first h a v e to k n o w s o m e t h i n g of t h e m a t h e m a t i c a l r e a l m — w h i c h is p r e c i s e l y w h a t w e w e r e trying to e x p l a i n . T h e r e are t h e r e f o r e real difficulties, for a p l a t o n i s t , in a p p e a l i n g to e v o l u t i o n a r y v e r s i o n s of n a t i v i s m to explain o u r k n o w l e d g e of m a t h e m a t i c s . For o n t h e o n e h a n d it is i m p l a u s ible that s u c h k n o w l e d g e s h o u l d b e i n n a t e in its o w n right. O n the o t h e r , a t t e m p t s to explain s u c h k n o w l e d g e in t e r m s of o u r k n o w l e d g e of logic, o r in t e r m s of o u r k n o w l e d g e of g r a m m a r (both of w h i c h a r e very p r o b a b l y i n n a t e ) , a r e b e s e t with difficulties. It is, h o w e v e r , w o r t h c o n s i d e r i n g w h e t h e r thereare a n y f u r t h e r — m o r e g e n e r a l — a r g u m e n t s a g a i n s t nativistic p l a t o n i s m . T o this topic 1 n o w t u r n .

Evolutionary Platonism? T h e m a i n p r o b l e m for a p l a t o n i s t , as I s e e it, is to explain w h y n a t u r a l s e l e c t i o n of a faculty of intuition s h o u l d be a reliable p r o c e s s , l e a d i n g u s to h a v e true b e l i e f s a b o u t the abstract r e a l m . F o r w h a t d i f f e r e n c e c o u l d the w a y t h i n g s are in s u c h a realm m a k e to o u r c h a n c e s of survival in t h e physical w o r l d ? If w e are to a p p e a l to e v o l u t i o n to e x p l a i n o u r i n n a t e k n o w l e d g e of the a b s t r a c t r e a l m , t h e n it m u s t be s u p p o s e d that p o s s e s s i n g t r u t h s a b o u t s u c h a realm will m a k e a d i f f e r e n c e to o u r survival. T h o s e early h u m a n s w h o h a p p e n e d (as a r e s u l t of r a n d o m m u t a t i o n s ) to h a v e true beliefs a b o u t s u c h a r e a l m w o u l d h a v e to h a v e h a d a b e t t e r c h a n c e of s u r v i v i n g t h a n t h o s e w h o did n o t . But w h a t d i f f e r e n c e c a n a b s t r a c t o b j e c t s m a k e to o u r s u r v i v a l ? Y o u c a n n o t eat a n a b s t r a c t o b j e c t , n o r p o i s o n y o u r s e l f w i t h o n e . N o r c a n i g n o r a n c e of a n a b s t r a c t o b j e c t lead y o u to b e e a t e n b y a tiger or d r o w n e d in a f l o o d . S o h o w c a n t r u e b e l i e f s a b o u t t h e abstract r e a l m (or a faculty w h o s e c o n s t i t u e n t s t r u c t u r e e n a b l e s u s to o b t a i n true beliefs a b o u t t h a t r e a l m ) h a v e b e e n reliably s e l e c t e d in e v o l u t i o n ? In r e p l y , it m i g h t b e said that m a t h e m a t i c a l t r u t h s a r e e x t r e m e l y u s e f u l to t h o s e w h o p o s s e s s t h e m . F o r e x a m p l e , t h e y c a n e n a b l e y o u to w o r k o u t w h a t w o u l d b e a s u f f i c i e n t store of

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f o o d to s e e y o u r f a m i l y t h r o u g h a w i n t e r . I g n o r a n c e of a t r u t h s u c h a s 'If w e n e e d 6 kilos of rice a d a y , w e shall n e e d 9 0 0 kilos of rice to last t h r o u g h a w i n t e r of 150 d a y s ' m a y lead s o m e o n e to die of s t a r v a t i o n . S o m e t h i n g similar will b e true o f logical a n d g r a m m a t i c a l t r u t h s a s w e l l — t h e f o r m e r u n d e r l y i n g all p l a n n i n g a n d r e a s o n i n g ; k n o w l e d g e of t h e latter b e i n g w h a t m a k e s communication possible. E m p i r i c i s t s h a v e traditionally p r o v i d e d a n u m b e r of e x p l a n a t i o n s of t h e u s e f u l n e s s of m a t h e m a t i c a l t r u t h s , r a n g i n g f r o m t h e s u g g e s t i o n that t h e y c o n c e r n internal r e l a t i o n s b e t w e e n o u r c o n c e p t s to the idea that they c o n s i s t of h i g h - l e v e l e m p i r i c a l g e n e r a l i z a t i o n s . But w h a t is h a r d to s e e is h o w facts a b o u t p l a t o n i c o b j e c t s c o u l d e n t e r into the e x p l a n a t i o n of t h e u s e f u l n e s s of m a t h e m a t i c s a n d logic. If a b s t r a c t o b j e c t s c a n n o t c a u s a l l y affect the natural w o r l d , t h e n p r e s u m a b l y t h e r e is at m o s t s o m e sort of structural c o r r e s p o n d e n c e b e t w e e n t h e t w o r e a l m s , in v i r t u e of w h i c h p u r e m a t h e m a t i c s c a n b e c o m e a p p l i e d . K n o w l e d g e of t h e s e structural f e a t u r e s of the natural w o r l d itself w o u l d t h e n suffice for w h a t e v e r practical a d v a n t a g e is to b e gained from mathematics. T h u s it surely c a n n o t b e i g n o r a n c e of t h e p r o p e r t i e s of t h e a b s t r a c t o b j e c t s 6, 9 0 0 , a n d 150, as s u c h , w h i c h w o u l d lead m e to die of s t a r v a t i o n in the e x a m p l e a b o v e . R a t h e r , it w o u l d b e i g n o r a n c e of t h e g e n e r a l structural f e a t u r e s of t h e p h y s i c a l w o r l d in virtue of w h i c h it is true that 150 p a r c e l s of 6 kilos of rice m a k e s 9 0 0 kilos. It w o u l d t h e r e f o r e b e sufficient for m e to s u r v i v e that I s h o u l d k n o w s o m e g e n e r a l truth f r o m w h i c h it f o l l o w s t h a t , in o r d e r to h a v e a parcel of rice for e a c h d a y of t h e w i n t e r , e a c h of w h i c h w h e n p l a c e d o n t h e scales will tip t h e n e e d l e to t h e '6 k i l o s ' m a r k , I m u s t collect a q u a n t i t y of rice that will tip the n e e d l e to t h e ' 9 0 0 k i l o s ' m a r k . T h i s is n o t k n o w l e d g e of a b s t r a c t o b j e c t s as s u c h , b u t r a t h e r k n o w l e d g e of t h e m a n n e r in w h i c h b o d i e s of m a t t e r in t h e p h y s i c a l w o r l d m a y b e c o l l e c t e d t o g e t h e r or d i v i d e d u p . ( T h e p l a t o n i s t v i e w , in c o n t r a s t , m u s t b e that these properties of matter are structurally isomorphic with t h e p r o p e r t i e s of o b j e c t s in t h e a b s t r a c t r e a l m , s o t h a t k n o w i n g t h e latter t h e r e b y p r o v i d e s u s w i t h k n o w l e d g e of t h e f o r m e r . ) It t h e r e f o r e r e m a i n s p r o b l e m a t i c w h y e v o l u t i o n s h o u l d b e reliable in s e l e c t i n g b e l i e f s a b o u t t h e a b s t r a c t r e a l m . F o r it is n o t truths about that realm as such that are a n aid to survival, b u t

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r a t h e r t r u t h s a b o u t t h e structural f e a t u r e s of t h e p h y s i c a l w o r l d in v i r t u e of w h i c h t h e t r u t h s of m a t h e m a t i c s c a n b e a p p l i e d to that w o r l d . T h e s e t r u t h s a b o u t t h e p h y s i c a l w o r l d c o u l d p o s s i b l y h a v e b e e n reliably s e l e c t e d t h r o u g h e v o l u t i o n . B u t to g o b e y o n d t h i s , to h a v e t r u e b e l i e f s a b o u t t h e a b s t r a c t r e a l m itself, w o u l d c o n f e r n o a d d i t i o n a l a d v a n t a g e in survival. In w h i c h c a s e it s e e m s that a p l a t o n i s t c a n n o t e x p l a i n in e v o l u t i o n a r y t e r m s h o w k n o w l e d g e of t h e abstract r e a l m c a n c o m e to b e i n n a t e . T h i s will t h e n l e a v e an e m p i r i c i s t , w h o r e j e c t s c l a i m s to k n o w l e d g e that c a n n o t b e g i n to b e e x p l a i n e d , w i t h s u f f i c i e n t r e a s o n for d e n y i n g that w e can h a v e k n o w l e d g e of m a t h e m a t i c s , if its s u b j e c t m a t t e r is c o n s t r u e d platonistically. N o w t h e p o i n t h e r e is n o t that e v o l u t i o n c a n n o t s e c u r e m o r e t h a n is n e c e s s a r y to m e e t t h e n e e d s of s u r v i v a l . Plainly it c a n , if r a n d o m m u t a t i o n s a r e w h a t fuel t h e e v o l u t i o n a r y p r o c e s s . It is r a t h e r that e v o l u t i o n a r y s e l e c t i o n of beliefs is o n l y a reliable p r o c e s s to the e x t e n t that it is t h e truth of t h e beliefs t h a t c o n f e r s a d v a n t a g e in survival. W h e n it c o m e s to b e l i e f s w h o s e c o n t e n t g o e s b e y o n d t h o s e structural f e a t u r e s of t h e n a t u r a l w o r l d that m a y m a t t e r for s u r v i v a l , n a t u r a l s e l e c t i o n is j u s t a s likely to p r o d u c e beliefs that a r e w r o n g a s right. It will n o t m a t t e r for survival if i n n a t e m a t h e m a t i c a l b e l i e f s a r e false w i t h r e s p e c t to t h e p l a t o n i c r e a l m , p r o v i d e d that t h e y w o r k s u c c e s s f u l l y in t h e natural world. R e m e m b e r that w h a t e v o l u t i o n w o u l d in t h e first i n s t a n c e deliver w o u l d b e a faculty for m a n i p u l a t i n g r e p r e s e n t a t i o n s of p l a t o n i c o b j e c t s , f i n d i n g s o m e b u t n o t o t h e r s of t h e s e r e p r e s e n t a t i o n s intuitively a c c e p t a b l e . B u t s i n c e t h e survival v a l u e of t r u t h s a b o u t p l a t o n i c o b j e c t s d e r i v e s e n t i r e l y f r o m t h e s u p p o s e d structural c o r r e s p o n d e n c e b e t w e e n t h e n a t u r a l a n d p l a t o n i c r e a l m s , e v o l u t i o n c o u l d o n l y b e reliable i n r e s p e c t of t h o s e structural f e a t u r e s o f t h e n a t u r a l w o r l d . T h a t is, it w o u l d lead u s to find '2 + 2 = 4 ' intuitively a c c e p t a b l e w h e n , a n d o n l y w h e n , it is true t h a t t h i n g s m a y g e n e r a l l y b e d i v i d e d u p , a n d c o m b i n e d , a n d c o u n t e d in s u c h a m a n n e r . In fact w e c a n easily i m a g i n e w o r l d s w h e r e ' 2 + 2 = 4 ' w o u l d n o t b e s e l e c t e d for, b u t r a t h e r , if a n y t h i n g , '2 + 2 = 5 ' . F o r example, a world w h e r e 2 apples a n d 2 pears put into a lunchb o x p r o d u c e a fifth p i e c e o f fruit, or a w o r l d w h e r e t h e v e r y act of c o u n t i n g t h e u n i o n of t h e t w o s e t s p r o d u c e s a n e x t r a m e m b e r ,

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a n d s o o n . S o h o w c o u l d w e k n o w that o u r i n n a t e belief that 2 + 2 = 4 is n o t of this sort? M a y b e , in t h e p l a t o n i c r e a l m , 2 + 2 is really 5 , b u t t h e structural facts a b o u t t h e natural w o r l d are s u c h as to m a k e '2 + 2 = 4 ' a p p l y to it. T h e p o i n t h e r e n e e d s stating with s o m e c a r e . For if e v o l u t i o n s e l e c t s a faculty of m a t h e m a t i c a l intuition in virtue of t h e a c c e s s that t h e latter g i v e s u s to structural facts a b o u t the n a t u r a l w o r l d , a n d if t h e r e is in fact a structural c o r r e s p o n d e n c e b e t w e e n t h e natural a n d p l a t o n i c w o r l d s , t h e n e v o l u t i o n will b e reliable in d e l i v e r i n g u s t r u t h s a b o u t the p l a t o n i c r e a l m . H e n c e w e w o u l d , in t h e s e c i r c u m s t a n c e s , h a v e i n n a t e first-order k n o w l e d g e of platonic o b j e c t s . A n d w e c a n n o t h e r e o b j e c t , a g a i n s t t h e t h e s i s that e v o l u t i o n is reliable with r e s p e c t to t h e platonic d o m a i n , that if the m a t h e m a t i c a l facts h a d b e e n d i f f e r e n t , e v o l u t i o n w o u l d still h a v e s e l e c t e d for us the very s a m e m a t h e m a t i c a l b e l i e f s . For w e c a n n o t intelligibly s u p p o s e that t r u t h s that a r e n e c e s s a r y ( a s a r e t h o s e of m a t h e m a t i c s ) c a n b e o t h e r than they a r e . It s e e m s that an a p p e a l to e v o l u t i o n c a n , a f t e r all, e x p l a i n h o w i n n a t e k n o w l e d g e of p l a t o n i c o b j e c t s is p o s s i b l e , g i v e n a reliabilist c o n c e p t i o n of k n o w l e d g e . But w h a t a p p e a l s to e v o l u t i o n cannot d o is p r o v i d e us w i t h a n y r e a s o n for t h i n k i n g that t h e r e is a structural c o r r e s p o n d e n c e b e t w e e n t h e p l a t o n i c a n d n a t u r a l r e a l m s . For w e c a n n o t , in this c o n t e x t , take o u r k n o w l e d g e of 2 + 2 = 4 for g r a n t e d . W h i l e this p r o p o s i t i o n m a y strike u s as intuitively o b v i o u s , o u r q u e s t i o n is p r e c i s e l y w h e t h e r w e h a v e a n y r e a s o n to t h i n k that o u r i n t u i t i o n s are a g o o d g u i d e to the s t a t e s of t h e p l a t o n i c r e a l m . A p p e a l s to e v o l u t i o n t h e r e f o r e c a n n o t give u s t h e k n o w l e d g e ( s e c o n d o r d e r ) that w e h a v e k n o w l e d g e of p l a t o n i c o b j e c t s . O n t h e c o n t r a r y , it can o n l y g e n e r a t e s c e p t i c i s m o n t h e i s s u e . If w e h a d n o o t h e r o p t i o n b u t to a c c e p t t h e p l a t o n i s t i n t e r p r e t a t i o n of t h e s u b j e c t - m a t t e r of a r i t h m e t i c , t h e n t h e o n l y p r o p e r c o n c l u s i o n w o u l d b e that w e h a v e n o r e a s o n to t h i n k that w e h a v e a n y k n o w l e d g e of that s u b j e c t - m a t t e r ( n a m e l y , of p l a t o n i c o b j e c t s ) . B u t of c o u r s e t h e r e a r e o t h e r o p t i o n s a v a i l a b l e , a s w e s a w in c h a p t e r 3. A p p e a l s to e v o l u t i o n t h e r e f o r e c a n n o t r e n d e r p l a t o n i s m a c c e p t a b l e to a c o n t e m p o r a r y e m p i r i c i s t . W h i l e e v o l u t i o n m a y p o s s i b l y e x p l a i n h o w i n n a t e k n o w l e d g e of p l a t o n i c o b j e c t s is p o s s i b l e , it c a n n o t p r o v i d e u s w i t h a n y r e a s o n

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for t h i n k i n g that s u c h k n o w l e d g e actually e x i s t s . W h i l e t h i s is t h e c a s e , it will r e m a i n n e c e s s a r y for a n e m p i r i c i s t — w h o i n s i s t s that c l a i m s to k n o w l e d g e s h o u l d o n l y b e a l l o w e d w h e r e w e c a n b e g i n t o s e e in n a t u r a l t e r m s w h y w e a r e reliable in m a k i n g those c l a i m s — t o continue to reject platonism.

O t h e r Rationalist Beliefs It t u r n s o u t that t h e e m p i r i c i s t o b j e c t i o n to p l a t o n i s m r e m a i n s intact, e v e n g i v e n m y c o n s t r u a l of t h e c o r e o f e m p i r i c i s m , a n d the c o n s e q u e n t e m p i r i c i s t a c c e p t a n c e o f e v o l u t i o n a r y n a t i v i s m . But w h a t o f o t h e r a s p e c t s of t h e traditional d e b a t e b e t w e e n e m p i r i c i s t s a n d rationalists? W h a t of e m p i r i c i s t o b j e c t i o n s to t h e c l a i m s o f rationalists that w e c a n h a v e a priori k n o w l e d g e o f t h e e x i s t e n c e o f G o d , of t h e e x i s t e n c e a n d i m m o r t a l i t y o f t h e s o u l , o r of t h e f r e e d o m o f t h e will? O n m y a c c o u n t , t h e m o s t f u n d a m e n tal o f t h e s e o b j e c t i o n s is that n o naturalistic e x p l a n a t i o n c a n b e p r o v i d e d o f t h e m a n n e r in w h i c h w e m i g h t a c q u i r e s u c h k n o w l e d g e . C a n this, too, survive t h e empiricist acceptance of nativism? H e r e , a s b e f o r e , t h e m a i n i s s u e is w h e t h e r t h e b e l i e f s in q u e s t i o n , o r t h e faculty o f t h o u g h t that e n a b l e s u s to intuit t h e t r u t h o f t h o s e b e l i e f s , c o u l d h a v e b e e n reliably s e l e c t e d t h r o u g h e v o l u t i o n . F o r t h e s a k e of s i m p l i c i t y , let u s c o n f i n e o u r s e l v e s t o c o n s i d e r a t i o n of o n l y o n e of t h e s e f o r m s o f n a t i v i s m . L e t u s c o n s i d e r t h e s u g g e s t i o n that w e p o s s e s s a n i n n a t e faculty o f m i n d thaf. e n a b l e s u s to d i s c o v e r t h e t r u t h of t h e b e l i e f s in q u e s t i o n b y t h o u g h t a l o n e . O u r c o n c l u s i o n s will t h e n readily g e n e r a l i z e , to c o v e r t h e possibility o f i n n a t e belief a s well. C o n s i d e r , first, t h e s u g g e s t i o n that w e p o s s e s s a n i n n a t e c a p a c i t y f o r a c q u i r i n g k n o w l e d g e o f t h e e x i s t e n c e of G o d . C a n w e e x p l a i n h o w s u c h a faculty o f m i n d m i g h t h a v e b e e n reliably s e l e c t e d t h r o u g h e v o l u t i o n ? N o t e that w e c a n n o t a p p e a l t o t h e social o r p s y c h o l o g i c a l b e n e f i t s o f religious belief i n this c o n n e c t i o n ( s u p p o s i n g that t h e r e a r e a n y ) . F o r s u c h b e n e f i t s w o u l d b e i n d e p e n d e n t o f t h e truth o f t h e b e l i e f in q u e s t i o n . S e l e c t i o n o f a b e l i e f o n g r o u n d s u n r e l a t e d t o t r u t h is n o t a reliable m e t h o d o f a c q u i r i n g true b e l i e f s . S o e v e n if t h e faculty e n a b l i n g u s to arrive at b e l i e f i n G o d w e r e i n n a t e , a n d that b e l i e f

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w e r e t r u e , still o u r b e l i e f w o u l d n o t c o n s t i t u t e k n o w l e d g e if t h e e x p l a n a t i o n of its i n n a t e n e s s w e r e in t e r m s of b e n e f i t s u n r e l a t e d to truth. T h e o n l y t r u t h - r e l a t e d w a y in w h i c h belief in G o d c o u l d c o n c e i v a b l y h a v e v a l u e in survival w o u l d b e if s u c h a belief e n a b l e d o n e to s e c u r e , t h r o u g h p r a y e r , G o d ' s positive i n t e r v e n tion in t h e w o r l d . But this v i o l a t e s t h e e m p i r i c i s t c o n s t r a i n t that t h e e x p l a n a t i o n of a belief-acquisition p r o c e s s s h o u l d b e a natural o n e , m e n t i o n i n g only p r o c e s s e s that o p e r a t e in a c c o r d a n c e with causal l a w s . For G o d ' s i n t e r v e n t i o n in the w o r l d , for e x a m p l e to s a v e a life, w o u l d involve a violation of s u c h l a w s . S o I c o n c l u d e that e v e n an e m p i r i c i s t w h o a c c e p t s n a t i v i s m will still h a v e an o b j e c t i o n of principle to t h e rationalist claim that w e can h a v e a priori k n o w l e d g e of the e x i s t e n c e of G o d . C o n s i d e r , n o w , the s u g g e s t i o n that w e h a v e an i n n a t e l y g i v e n faculty of r e a s o n that e n a b l e s u s to d i s c o v e r a priori t h e e x i s t e n c e a n d i m m o r t a l i t y of the s o u l , or t h e f r e e d o m of the will. O n c e again it is difficult to s e e h o w a faculty with s u c h p o w e r s c o u l d h a v e b e e n reliably s e l e c t e d t h r o u g h e v o l u t i o n . For it is h a r d to s e e w h a t p o s s i b l e d i f f e r e n c e the p o s s e s s i o n of true beliefs on t h e s e m a t t e r s w o u l d m a k e to o u r survival. (Just as in t h e c a s e of belief in G o d , it is not sufficient to s h o w that the beliefs in q u e s t i o n h a v e survival v a l u e : p e r h a p s belief in i m m o r t a l i t y can k e e p u s f r o m d e s p a i r , for e x a m p l e , a n d p e r h a p s belief in f r e e d o m of the will is a n e c e s s a r y c o n d i t i o n of o u r h a v i n g moral b e l i e f s . It n e e d s to b e s h o w n that it is t h e p o s s e s s i o n of a true belief that a i d s s u r v i v a l , s i n c e o t h e r w i s e t h e belief-acquisition p r o c e s s will n o t b e a reliable o n e . ) It t h e r e f o r e f o l l o w s that an e m p i r i c i s t will o b j e c t to s u c h k n o w l e d g e - c l a i m s , o n t h e g r o u n d s that n o naturalistic a c c o u n t can b e g i v e n of t h e m a n n e r in w h i c h w e m i g h t a c q u i r e that k n o w l e d g e . M a n y p h i l o s o p h e r s h a v e c l a i m e d to b e able to d e m o n s t r a t e t h e e x i s t e n c e of t h e s o u l , for e x a m p l e , b e l i e v i n g that t h e y c o u l d e s t a b l i s h t h e c o n c e p t u a l i m p o s s i b i l i t y of o u r lacking a s o u l . In fact s u c h a r g u m e n t s g e n e r a l l y t u r n o u t to b e u n s o u n d . B u t e v e n s u p p o s i n g that s o m e s u c h a r g u m e n t w e r e to s u c c e e d , e m p i r i c i s t s w o u l d h a v e a f u r t h e r line of d e f e n c e . F o r s u p p o s e t h a t it h a d b e e n d e m o n s t r a t e d t h a t w e c a n n o t c o n c e i v e o t h e r 4

H o w e v e r , s e e m y Introducing c o m e s quite close to success. 4

Persons,

c h s . 2 a n d 3, for a n a r g u m e n t w h i c h

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w i s e t h a n that w e p o s s e s s a s o u l . A n e m p i r i c i s t will still d e m a n d to k n o w h o w w e c o m e to h a v e a faculty of r e a s o n that is c a p a b l e of d i s c o v e r i n g a priori the f u n d a m e n t a l n a t u r e of o u r s e l v e s . H o w can thought alone have acquired such powers? Unless s o m e e v o l u t i o n a r y e x p l a n a t i o n can b e d i s c o v e r e d , a n e m p i r i c i s t will w i s h to exploit the g a p b e t w e e n o u r inability to c o n c e i v e of s o m e t h i n g b e i n g o t h e r w i s e (a fact a b o u t u s a n d o u r c o n c e p t s ) , a n d t h e fact of s o m e t h i n g b e i n g s o (a fact a b o u t t h e w o r l d ) . E v e n if w e c a n n o t c o n c e i v e of o u r s e l v e s o t h e r w i s e t h a n p o s s e s s i n g a soul, this d o e s n o t m e a n that w e k n o w of the e x i s t e n c e of the s o u l . O n the c o n t r a r y , this latter k n o w l e d g e s h o u l d be d e n i e d of us. It m a y be w o r t h s t r e s s i n g in c o n c l u s i o n to this section that the e m p i r i c i s t o b j e c t i o n is n o t to t h e idea that r e a s o n , a s s u c h , h a s value in survival. T h a t w o u l d be a b s u r d . It is o b v i o u s that the h u m a n ability to r e a s o n is at least o n e of the distinctive f e a t u r e s u n d e r l y i n g t h e s u c c e s s of the s p e c i e s . T h e o b j e c t i o n is o n l y to t h e survival v a l u e of a faculty of r e a s o n that w o u l d c o n t a i n within itself the p o w e r to g e n e r a t e true beliefs a b o u t the m a t t e r s g e n e r a l l y b e l o v e d b y r a t i o n a l i s t s , s u c h a s the e x i s t e n c e of G o d or the soul.

Transcendental A r g u m e n t s Finally, let u s c o n s i d e r h o w e m p i r i c i s t s s h o u l d r e s p o n d to v a r i o u s f o r m s of t r a n s c e n d e n t a l a r g u m e n t , w h i c h a t t e m p t to s h o w a priori w h a t m u s t b e t h e c a s e a b o u t o u r s e l v e s or t h e w o r l d if e x p e r i e n c e is to b e p o s s i b l e at all. S u c h a r g u m e n t s w e r e d e v e l o p e d m o s t f a m o u s l y by I m m a n u e l K a n t in his Critique of Pure Reason, t h o u g h h e h a s h a d m a n y i m i t a t o r s . H i s p o s i t i o n is o f t e n t h o u g h t to p r o v i d e a k i n d of s y n t h e s i s of the e m p i r i c i s t a n d rationalist t r a d i t i o n s . F o r e x a m p l e , s u p p o s e it w e r e s u c c e s s fully a r g u e d that it is a c o n d i t i o n for t h e possibility of o u r e x p e r i e n c e that all e v e n t s s h o u l d h a v e c a u s e s . T h a t is, s u p p o s e it w e r e s h o w n to b e c o n c e p t u a l l y n e c e s s a r y that all e v e n t s m u s t h a v e c a u s e s , if t h e r e is to b e a n y e x p e r i e n c e at all. Is this s o m e t h i n g that m y sort of e m p i r i c i s t c o u l d in p r i n c i p l e a c c e p t ? T h e a n s w e r will in fact d e p e n d v e r y m u c h on h o w t h e c o n c l u s i o n of s u c h a n a r g u m e n t is to b e u n d e r s t o o d .

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S u p p o s e , first, that t h e c o n c l u s i o n p u r p o r t s to b e a t r u t h a b o u t a m i n d - i n d e p e n d e n t reality ( m a n y c o n t e m p o r a r y p h i l o s o p h e r s h a v e c o n s t r u c t e d t r a n s c e n d e n t a l a r g u m e n t s of this sort). T h e n in m y v i e w an e m p i r i c i s t s h o u l d o b j e c t to t h e possibility of o u r h a v i n g a priori k n o w l e d g e of it. F o r t h e fact ( s u p p o s i n g that it w e r e a fact) that w e c a n n o t c o n c e i v e of t h e w o r l d o t h e r w i s e t h a n g o v e r n e d by u n i v e r s a l c a u s a l i t y is n o t e n o u g h to e s t a b l i s h that all real e v e n t s d o h a v e c a u s e s . N o r is it at all o b v i o u s h o w a faculty for o b t a i n i n g s u c h k n o w l e d g e c o u l d h a v e b e e n reliably s e l e c t e d t h r o u g h e v o l u t i o n . N o d o u b t a true belief in universal causality m i g h t b e u s e f u l in s u r v i v a l . But g i v e n that o n l y a h a n d f u l of p e o p l e h a v e e v e r e m p l o y e d their s u p p o s e d i n n a t e faculty in o r d e r to d e m o n s t r a t e t h e e x i s t e n c e of u n i v e r s a l c a u s a l i t y , it is h a r d to s e e w h a t a d v a n t a g e the p o s s e s s i o n of s u c h a faculty c a n h a v e c o n f e r r e d t h r o u g h evolution. K a n t h i m s e l f s a w , at least partly, the e m p i r i c i s t c h a l l e n g e to r a t i o n a l i s m . ( H e r e g a r d e d it a s a c h a l l e n g e to s h o w a priori h o w r e a s o n can h a v e t h e p o w e r to g e n e r a t e k n o w l e d g e o f a n y t h i n g o u t s i d e itself, r a t h e r t h a n , as I p r o p o s e , a s a d e m a n d for a natural e x p l a n a t i o n of r e a s o n ' s reliability on s u c h m a t t e r s . ) H e p u t f o r w a r d his d o c t r i n e of T r a n s c e n d e n t a l I d e a l i s m in a n a t t e m p t to o v e r c o m e it. K a n t ' s v i e w is that t h e s t r u c t u r e of t h e h u m a n m i n d i m p o s e s an o r d e r on t h e w o r l d of o u r e x p e r i e n c e , a n d w h a t w e m a y k n o w a priori is limited to that w o r l d , c o n s i d e r e d as an o b j e c t of p o s s i b l e e x p e r i e n c e by u s . O n this v i e w , o u r p r o o f that all e v e n t s h a v e c a u s e s w o u l d b e g u a r a n t e e d to be reliable, b e c a u s e it is a s t r u c t u r e that r e a s o n itself i m p o s e s on t h e c o u r s e of o u r e x p e r i e n c e . T h e r e a r e , h o w e v e r , t w o d i f f e r e n t w a y s in w h i c h K a n t ' s Transcendental Idealism can be understood, each finding some b a s i s in h i s w r i t i n g s . T h e first r e g a r d s it as a sort of d u a l - a s p e c t r e a l i s m . O n this v i e w , t h e r e is a r e a l m of o b j e c t s e x i s t i n g i n d e p e n d e n t l y of o u r m i n d s ( h e n c e ' r e a l i s m ' ) . B u t t h o s e o b j e c t s c a n b e t h o u g h t of u n d e r t w o d i f f e r e n t a s p e c t s — f i r s t , a s p o s s i b l e o b j e c t s of o u r e x p e r i e n c e (as Phenomena), a n d , s e c o n d l y , as t h e y are in t h e m s e l v e s , i n d e p e n d e n t l y of o u r e x p e r i e n c e (as Noumena). All o u r k n o w l e d g e , w h e t h e r e m p i r i c a l o r a priori, w o u l d b e c o n f i n e d to t h e r e a l m of Phenomena. A n d t h e t r u t h t h a t all e v e n t s h a v e c a u s e s w o u l d b e i m p o s e d u p o n Phenomena b y t h e

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s t r u c t u r e o f o u r r e a s o n . B u t t h e n t h e r e is o n e i t e m o f k n o w l e d g e c l a i m e d o n this a c c o u n t t h a t cannot b e e x p l a i n e d a s a s t r u c t u r e i m p o s e d b y o u r r e a s o n o n o b j e c t s as Phenomena— n a m e l y , t h e claim t h a t t h e r e a r e o b j e c t s i n d e p e n d e n t o f o u r m i n d s ( t h e claim t h a t t h e r e a r e Noumena). S o if this is h o w K a n t is to b e i n t e r p r e t e d , h e is still w i d e o p e n to t h e e m p i r i c i s t challenge. Alternatively, Kant's Transcendental Idealism may be unders t o o d as a f o r m of s o p h i s t i c a t e d p h e n o m e n a l i s m . O n this v i e w , it c a n n o t b e k n o w n t h a t t h e r e are o b j e c t s i n d e p e n d e n t of o u r m i n d s , a n d all a priori k n o w l e d g e c o n c e r n s o n l y p a t t e r n s that t h e m i n d i m p o s e s o n t h e c o u r s e of o u r e x p e r i e n c e itself. O n this a c c o u n t , at least o n e of t h e e m p i r i c i s t o b j e c t i o n s of p r i n c i p l e to the e x i s t e n c e of t r a n s c e n d e n t a l a r g u m e n t s c o l l a p s e s . For t h e a priori k n o w l e d g e t h a t all e v e n t s h a v e c a u s e s , w h i l e b e i n g i n f o r m a t i v e (that is, n e w ) , w o u l d n o t b e g e n u i n e l y s u b s t a n t i v e (that i s , m i n d - i n d e p e n d e n t ) . T h e truth that all e v e n t s h a v e c a u s e s w o u l d in fact o n l y c o n c e r n t h e c o u r s e of o u r e x p e r i e n c e itself. A d m i t t e d l y , this t r u t h w o u l d b e , to a d e g r e e , s u b s t a n t i v e , since it is a c o n t i n g e n t fact t h a t t h e r e s h o u l d b e a n y e x p e r i e n c e at all. (Recall f r o m c h a p t e r 1 t h a t k n o w l e d g e m a y b e s u b s t a n t i v e by v i r t u e either of b e i n g c o n t i n g e n t or of c o n c e r n i n g s o m e reality i n d e p e n d e n t of o u r t h o u g h t s . ) B u t t h e s u b s t a n t i v e c o n t e n t of t h e claim t h a t all e v e n t s h a v e c a u s e s w o u l d n o t r e a c h a n y f u r t h e r t h a n t h e b a r e , b u t s u b s t a n t i v e , claim that t h e r e is e x p e r i e n c e . If t h i s is h o w K a n t is to b e i n t e r p r e t e d , t h e n in a t t e m p t i n g to s u r m o u n t t h e e m p i r i c i s t c h a l l e n g e h e h a s , in reality, s u r r e n d e r e d to it. F o r h e h a s failed to s h o w h o w s u b s t a n t i v e a priori k n o w l e d g e is p o s s i b l e . H e w o u l d o n l y h a v e b e e n p r e v e n t e d f r o m s e e i n g this b e c a u s e h e d o e s n o t disting u i s h clearly b e t w e e n k n o w l e d g e that is i n f o r m a t i v e a n d k n o w l e d g e t h a t is s u b s t a n t i v e . 5

6

In s u m m a r y , I c o n c l u d e t h a t m y p r o p o s e d a c c o u n t of t h e c o r e of e m p i r i c i s m l e a v e s m u c h o f t h e traditional d i s p u t e b e t w e e n e m p i r i c i s t s a n d r a t i o n a l i s t s i n t a c t . B o t h sides m a y n o w a c c e p t t h e e x i s t e n c e of i n n a t e k n o w l e d g e . B u t t h e y r e m a i n d i v i d e d o v e r 5

T h e r e r e m a i n s t h e difficulty o f e x p l a i n i n g h o w w e m a y k n o w a priori

that

r e a s o n d o e s i m p o s e a n a priori structure o n a n y possible e x p e r i e n c e . 6

S e e h i s v e r y c o n f u s e d e x p l a n a t i o n s of t h e a n a l y t i c — s y n t h e t i c d i s t i n c t i o n ,

f o r e x a m p l e at Critique

of Pure Reason A . 6 - 7 , B . 1 0 - 1 1 .

158

Evolutionary

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t h e g e n e r a l c l a i m t h a t it is p o s s i b l e for u s to k n o w t h a t w e h a v e s u b s t a n t i v e k n o w l e d g e t h r o u g h t h o u g h t a l o n e , as w e l l a s o v e r m a n y specific c l a i m s to a priori k n o w l e d g e .

11 Our Knowledge of the External World IN this c h a p t e r I shall b e g i n to c o n s i d e r t h e s i g n i f i c a n c e of m y p r o p o s e d a c c o u n t of t h e c o r e of e m p i r i c i s m for t h e p r o b l e m of scepticism.

Empiricist Epistemology W h a t w o u l d a n e m p i r i c i s t e p i s t e m o l o g y n o w l o o k like, if m y p r o p o s a l s c o n c e r n i n g the e s s e n t i a l s of e m p i r i c i s m w e r e a c c e p t e d ? O n e i s s u e h e r e is w h e t h e r a c o n t e m p o r a r y e m p i r i c i s t , w h o m a y a c c e p t t h e e x i s t e n c e of i n n a t e k n o w l e d g e , a n d h e n c e of o n e f o r m of s u b s t a n t i v e a priori k n o w l e d g e , will h a v e a n y t h i n g of i n t e r e s t to c o n t r i b u t e to c o n t e m p o r a r y d e b a t e s in e p i s t e m o l o g y . A t l e a s t a partial a n s w e r m a y b e p r o v i d e d from a m o n g s t the i d e a s d e f e n d e d in c h a p t e r 10. For t h e strictures a g a i n s t p l a t o n i s m , a n d i n d e e d a g a i n s t a n y c l a i m s to k n o w l e d g e w h e r e w e c a n n o t give a naturalistic a c c o u n t of t h e reliability o f t h e beliefa c q u i s i t i o n p r o c e s s e s i n v o l v e d , r e m a i n in f o r c e . T h e e m p i r i c i s t c o n s t r a i n t o n k n o w l e d g e - c l a i m s m a y b e e x p e c t e d to h a v e a d i s t i n c t i v e i m p a c t on e p i s t e m o l o g y . M a n y c l a i m s to k n o w l e d g e m a y b e d i s a l l o w e d b e c a u s e of it. T h e m a i n i s s u e I w i s h to c o n s i d e r , h o w e v e r , is w h e t h e r m y c o n t e m p o r a r y e m p i r i c i s m is a n y b e t t e r p l a c e d to c o m b a t s c e p t i c i s m , t h u s a l l o w i n g that w e c a n h a v e k n o w l e d g e o f t h e physical world around us. Traditional empiricism has b e e n c l o s e l y allied to s c e p t i c i s m , o r at l e a s t to p h e n o m e n a l i s m . W h i l e L o c k e t h o u g h t t h a t w e c o u l d h a v e k n o w l e d g e of a p h y s i c a l reality i n d e p e n d e n t o f o u r m i n d s , h i s a r g u m e n t s h a v e g e n e r a l l y b e e n considered weak. Most subsequent empiricists, from B e r k e l e y a n d H u m e t h r o u g h to R u s s e l l a n d A y e r , h a v e d o u b t e d

160

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World

w h e t h e r w e c o u l d h a v e k n o w l e d g e o f a p h y s i c a l w o r l d that is i n d e p e n d e n t of o u r m i n d s . I n s t e a d , t h e y h a v e e m b r a c e d s o m e f o r m of p h e n o m e n a l i s m , m a i n t a i n i n g that o u r o r d i n a r y talk a b o u t ' p h y s i c a l o b j e c t s ' m a y b e r e d u c e d to d e s c r i p t i o n s of i m m e d i a t e e x p e r i e n c e , or s e n s e - d a t a , a n d to d e s c r i p t i o n s of r e c u r r i n g p a t t e r n s w i t h i n that e x p e r i e n c e . It is w o r t h a s k i n g , t h e n , w h e t h e r t h e traditional e m p i r i c i s t c o m m i t m e n t to p h e n o m e n a l i s m is in a n y w a y c o n n e c t e d w i t h o p p o s i t i o n to n a t i v i s m . It m a y a l s o b e w o r t h l o o k i n g again at t h e p r e s s u r e s that h a v e t e n d e d to p u s h e m p i r i c i s t s t o w a r d s s c e p t i c i s m . H o w e v e r , w e n e e d to be clear at the o u t s e t a b o u t t h e d i f f e r e n t levels i n v o l v e d in o u r e n q u i r y . For, g i v e n a reliabilist c o n c e p t i o n of k n o w l e d g e , of the sort d e f e n d e d in c h a p t e r 5 , w e shall in fact h a v e k n o w l e d g e in a n y d o m a i n w h e r e w e p o s s e s s reliably c a u s e d true b e l i e f s . S o , p r o v i d e d that t h e r e is in fact a physical w o r l d , a n d that t h e p r o c e s s e s that give rise to o u r beliefs a b o u t that w o r l d (either p e r c e p t i o n , or natural s e l e c t i o n , or s o m e c o m b i n a t i o n of t h e t w o ) a r e in fact g e n e r a l l y reliable o n e s , t h e n w e d o i n d e e d h a v e k n o w l e d g e of t h e w o r l d . But this will b e of little h e l p to u s in c o m b a t i n g s c e p t i c i s m . For t h e k n o w l e d g e in q u e s t i o n w o u l d b e entirely first-order, w h e r e a s the k n o w l e d g e that w e w a n t is s e c o n d - o r d e r . W e w a n t to k n o w ( s e c o n d - o r d e r ) w h e t h e r w e d o i n d e e d h a v e k n o w l e d g e (first-order) of t h e physical w o r l d . If w e c a n n o t k n o w t h i s , t h e n w e c a n n o t a n s w e r t h e s c e p t i c . O u r t a s k , t h e n , is to s e e w h e t h e r a c o n t e m p o r a r y e m p i r i c i s t m a y h a v e sufficient r e a s o n to b e l i e v e that w e h o l d reliably c a u s e d t r u e beliefs a b o u t t h e p h y s i c a l w o r l d .

Anti-Nativism and P h e n o m e n a l i s m P h e n o m e n a l i s m m a y p l a u s i b l y b e v i e w e d a s a n a t t e m p t to r e c o n c i l e sceptical a r g u m e n t s w i t h c o m m o n - s e n s e b e l i e f s . S u p p o s e w e a c c e p t that all k n o w l e d g e m u s t b e g r o u n d e d in t h e data of i m m e d i a t e e x p e r i e n c e . S u p p o s e , a l s o , that w e a g r e e that t h e r e c a n b e n o k n o w l e d g e , o n this b a s i s , of a n y t h i n g that is i n d e p e n d e n t of e x p e r i e n c e . T h e n t h e p h e n o m e n a l i s t s h o u l d b e s e e n as a t t e m p t i n g to a c c o m m o d a t e this c o n c l u s i o n w i t h i n c o m m o n - s e n s e , by analysing the contents of ordinary beliefs i n t o m e r e d e s c r i p t i o n s of p a t t e r n s w i t h i n i m m e d i a t e e x p e r i e n c e


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itself. T h i s p r o j e c t h a s p r o v e d r e m a r k a b l y difficult to carry t h r o u g h to c o m p l e t i o n . I n d e e d , s o far as I a m a w a r e , n o r e m o t e l y p l a u s i b l e p h e n o m e n a l i s t a n a l y s i s of a n y p r o p o s i t i o n about physical objects has ever been provided. But most e m p i r i c i s t s h a v e , in o n e w a y or a n o t h e r , b e e n c o m m i t t e d to j u s t s u c h a p r o g r a m m e of a n a l y s i s . T h e r e a s o n i n g b e h i n d the idea that all k n o w l e d g e m u s t b e g r o u n d e d in i m m e d i a t e e x p e r i e n c e , w h i c h a l s o s e e m s to entail t h e possibility of a p h e n o m e n a l i s t a n a l y s i s of o u r c o n c e p t s , c o m e s partly f r o m t h e a n t i - n a t i v i s m i n h e r e n t in traditional e m p i r i c i s m . A s w e s a w briefly in c h a p t e r 1, if n o n e of o u r k n o w l e d g e is i n n a t e , a n d n o n e a priori, t h e n all k n o w l e d g e m u s t b e l e a r n e d f r o m e x p e r i e n c e . A n d if n o c o n c e p t s a r e i n n a t e , and there are n o innate domain-specific mental structures e m b o d y i n g i n f o r m a t i o n a b o u t t h e w o r l d , t h e n the e x p e r i e n c e in q u e s t i o n m u s t b e u n c o n c e p t u a l i z e d a n d u n s t r u c t u r e d . S o , from this anti-nativist p e r s p e c t i v e , t h e b a s i s of all k n o w l e d g e w o u l d h a v e to b e a set of e x p e r i e n c e s that a r e n o t s t r u c t u r e d in s u c h a w a y as to c o n t a i n r e p r e s e n t a t i o n s of a n y t h i n g o u t s i d e t h e m s e l v e s — t h a t is to s a y , a set of s e n s e - d a t a . A n t i - n a t i v i s t s will of c o u r s e allow that t h e m i n d is i n n a t e l y d i v i d e d i n t o d i f f e r e n t faculties. T h e y m i g h t also allow that the m i n d h a s an i n n a t e ability to d i s t i n g u i s h t h e differing a t t r i b u t e s of o u r v a r i o u s s e n s e - d a t a , for e x a m p l e r e c o g n i z i n g t h e differe n c e b e t w e e n a s e n s a t i o n of red a n d a s e n s a t i o n of g r e e n , a n d d i s t i n g u i s h i n g a p a i n f r o m a t i c k l e . F o r t h e s e abilities d o n o t embody information about anything b e y o n d our sense-data t h e m s e l v e s . B u t f o r a n a n t i - n a t i v i s t this w o u l d b e t h e full e x t e n t of t h e f o u n d a t i o n o n w h i c h t h e s u p e r s t r u c t u r e of o u r k n o w l e d g e w o u l d h a v e to rest. 1

A s s o o n a s w e a c c e p t that o u r p e r c e p t u a l faculties m a y b e innately structured, h o w e v e r , the picture changes dramatically. F o r in that c a s e t h e b a s i s of e m p i r i c a l k n o w l e d g e w o u l d n o t b e s e n s e - d a t a , b u t p e r c e p t i o n s of o b j e c t s in s p a c e o u t s i d e u s . I a r g u e d in c h a p t e r 6 that o u r v i s u a l faculty, in p a r t i c u l a r , is i n n a t e l y s t r u c t u r e d s o that i n c o m i n g i n f o r m a t i o n is a u t o m a t i c ally p r e s e n t e d to u s in t h e f o r m of r e p r e s e n t a t i o n s of a n a r r a y of E v e n Q u i n e , w h o is in o t h e r r e s p e c t s n o t a n o r d i n a r y e m p i r i c i s t , s e e m s p r e p a r e d t o a l l o w little m o r e t h a n t h i s . S e e his c o n c e s s i o n o f i n n a t e q u a l i t y s p a c e s in ' N a t u r a l K i n d s ' , in Ontological Relativity. 1

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p h y s i c a l o b j e c t s in t h r e e - d i m e n s i o n a l s p a c e . It will b e t h e b e l i e f s a r i s i n g o u t of t h e s e r e p r e s e n t a t i o n s t h a t f o r m t h e f o u n d a t i o n s of o u r e m p i r i c a l k n o w l e d g e . It will a l s o b e t h e s e r e p r e s e n t a t i o n s that p r o v i d e t h e m a t e r i a l s for m a n y of o u r c o n c e p t s , p e r h a p s in t h e m a n n e r o u t l i n e d in c h a p t e r 7. N o t i c e that t h e s e c o n c e p t s will c o n s t i t u t e m o d e s of c l a s s i f y i n g p h y s i c a l o b j e c t s , r a t h e r t h a n b e i n g a b s t r a c t i o n s o u t of, a n d m o d e s of c l a s s i f y i n g , s e n s e - d a t a , a s p h e n o m e n a l i s t s w o u l d m a i n t a i n . I n d e e d , v i e w e d from this nativist p e r s p e c t i v e , s e n s e - d a t a t h e m s e l v e s b e c o m e entirely m a r g i n a l i z e d , p l a y i n g n o significant role w i t h i n the s t r u c t u r e of o u r b e l i e f - s y s t e m s , e x c e p t in s o far a s t h o s e beliefs h a p p e n to b e c o n c e r n e d explicitly with o u r s u b j e c t i v e s e n s a t i o n s . It is very likely true that o u r e x p e r i e n c e is i n n a t e l y d e t e r m i n e d a s r e p r e s e n t i n g a w o r l d of physical o b j e c t s in s p a c e a r o u n d u s . O n c e this is a c c e p t e d by c o n t e m p o r a r y e m p i r i c i s t s , e v e n as a m e r e possibility, they i m m e d i a t e l y lose a n y m o t i v e for a t t e m p t i n g a p h e n o m e n a l i s t r e d u c t i o n of c o n c e p t s . F o r t h e r e is t h e n n o r e a s o n to t h i n k that all c o n c e p t s m u s t be c o n s t r u c t e d out of s e n s e - d a t a . I n d e e d , if this form of n a t i v i s m is correct, t h e n w e h a v e f o u n d an e x p l a n a t i o n of w h y s u c h r e d u c t i o n s h a v e p r o v e d s o difficult to c o m p l e t e . But w o u l d this m e a n that w e s h o u l d also h a v e laid to rest t h e t h r e a t of s c e p t i c i s m ? U n f o r t u n a t e l y n o t . For it is o n e t h i n g to say that o u r p e r c e p t i o n s i n n a t e l y r e p r e s e n t to u s a w o r l d of p h y s i c a l o b j e c t s o u t s i d e u s . It is quite a n o t h e r t h i n g to say that t h e y truly r e p r e s e n t s u c h a w o r l d . It m a y b e i n n a t e l y d e t e r m i n e d that s o m e of o u r b e l i e f s , concerning perceived physical objects, constitute the foundation of o u r c o g n i t i v e s y s t e m , w h i l e t h o s e b e l i e f s t h e m s e l v e s are false. T o s a y that it is b e l i e f s a b o u t p h y s i c a l o b j e c t s , r a t h e r t h a n b e l i e f s a b o u t s e n s e - d a t a , t h a t a r e f o u n d a t i o n a l , is n o t to s a y that t h e w h o l e s y s t e m of o u r b e l i e f s m i g h t n o t b e built u p o n s a n d . T o s e e that this is s o , n o t i c e that w e c a n h a v e a p p a r e n t p e r c e p t i o n s of o b j e c t s in s p a c e o u t s i d e u s that a r e illusory. I c a n s e e m to s e e a m a n l u r k i n g in t h e b u s h e s , w h i l e all that is really t h e r e is a p l a y of s h a d o w s . I n d e e d , in c a s e s of h a l l u c i n a tion, a n d p e r h a p s also in d r e a m s , w e c a n b e p r e s e n t e d w i t h a p p a r e n t p e r c e p t i o n s of a t h r e e - d i m e n s i o n a l reality that is w h o l l y u n r e a l . M o r e o v e r , o n e o n l y n e e d s to recall D e s c a r t e s ' s h y p o t h e s i s of t h e o m n i p o t e n t d e m o n to realize that it is at l e a s t c o n c e p t u a l l y p o s s i b l e that all o u r e x p e r i e n c e m i g h t b e j u s t as it


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i s , a n d all o u r f o u n d a t i o n a l b e l i e f s a b o u t p h y s i c a l reality j u s t a s t h e y a r e , w h i l e t h e r e is in fact n o p h y s i c a l w o r l d for t h o s e e x p e r i e n c e s or b e l i e f s to c o n c e r n . W h i l e n a t i v i s m m i g h t h e l p u s to a v o i d a c o m m i t m e n t to p h e n o m e n a l i s m , it d o e s n o t , o n t h e f a c e of it, h e l p u s to a v o i d s c e p t i c i s m .

Varieties o f F o u n d a t i o n It m i g h t in a n y c a s e b e q u e s t i o n e d w h e t h e r t h e sort of e m p i r i c i s t n a t i v i s m s k e t c h e d a b o v e is really c o h e r e n t , or at a n y rate c o n s i s t e n t with f o u n d a t i o n a l i s m . For h o w c a n t h e r e b e f o u n d a t i o n s to o u r beliefs that a r e n o t c o m p l e t e l y c e r t a i n ? It m i g h t b e claimed that to say that a belief is f o u n d a t i o n a l is to say that it d o e s n o t require s u p p o r t f r o m a n y o t h e r belief. A n d d o e s this n o t entail that t h e belief in q u e s t i o n m u s t b e c e r t a i n ? For if a f o u n d a t i o n a l belief P w e r e uncertain, this w o u l d surely m e a n that t h e r e m u s t b e s o m e o t h e r p o s s i b l e belief Q that w o u l d lead u s to o v e r t u r n P. But t h e n , it m a y b e c l a i m e d , P does r e q u i r e s u p p o r t after all, n a m e l y f r o m t h e b e l i e f that n o t Q ; w h i c h c o n t r a d i c t s t h e h y p o t h e s i s that P i s f o u n d a t i o n a l . T h i s a r g u m e n t i n v o l v e s a c o n f u s i o n of l e v e l s , h o w e v e r . F o r w h a t is f o u n d a t i o n a l to a c o g n i t i v e s y s t e m (a s y s t e m of firsto r d e r beliefs) is n o t n e c e s s a r i l y w h a t is f o u n d a t i o n a l in e p i s t e m o l o g y , w h e r e o u r c o n c e r n is to k n o w w h a t w e k n o w . W e c a n insist that o u r p e r c e p t u a l b e l i e f s a b o u t t h e physical w o r l d c o n s t i t u t e t h e i n n a t e l y d e t e r m i n e d f o u n d a t i o n of o u r first-order s y s t e m of b e l i e f s , s i n c e t h e s e beliefs a r e p r i m i t i v e , a n d a r e h e l d i n d e p e n d e n t l y (in g e n e r a l ) of o u r o t h e r b e l i e f s . B u t at t h e s a m e t i m e w e c a n allow that t h e s e b e l i e f s , in b e i n g u n c e r t a i n , d o n o t c o n s t i t u t e an a p p r o p r i a t e f o u n d a t i o n for e p i s t e m o l o g y . If o u r c o n c e r n is to s h o w that o u r p e r c e p t u a l b e l i e f s a b o u t t h e w o r l d c o n s t i t u t e k n o w l e d g e , t h e n w e clearly c a n n o t s i m p l y t a k e t h e t r u t h of t h o s e b e l i e f s for g r a n t e d . It is w o r t h s t r e s s i n g a g a i n t h a t t h e task o f e p i s t e m o l o g y remains essentially the same, w h e t h e r w e endorse justificationa l i s m or reliabilism a s a t h e o r y of k n o w l e d g e — n a m e l y , to j u s t i f y o u r first-order c l a i m s t o k n o w l e d g e . In t h e c a s e of j u s t i f i c a t i o n a l i s m this is s o b e c a u s e k n o w l e d g e itself r e q u i r e s j u s t i f i c a t i o n . B u t for a reliabilist it will a l s o b e t r u e , g i v e n t h a t o u r a i m is t o

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k n o w w h a t w e k n o w (to a c h i e v e s e c o n d - o r d e r k n o w l e d g e ) . F o r t h e o n l y g e n e r a l l y reliable m e t h o d of f o r m i n g s e c o n d - o r d e r b e l i e f s c o n c e r n i n g w h i c h of o u r first-order b e l i e f s are b o t h true a n d reliably c a u s e d is to find c o n v i n c i n g r e a s o n s for b e l i e v i n g that w e h a v e k n o w l e d g e . ( A n o t h e r p o i n t is that the very m o s t that w e c o u l d h o p e to o b t a i n in a n y c a s e , f r o m a t t e m p t s t o c o m b a t s c e p t i c i s m by p r o v i d i n g reliabilist d e f i n i t i o n s o f t h e k e y c o n c e p t s , w o u l d b e to shift s c e p t i c i s m f r o m o n e p l a c e to a n o t h e r . E v e n if s c e p t i c i s m a b o u t k n o w l e d g e , a n d a b o u t justified belief, could be b l o c k e d — b y virtue of a reliabilist a c c o u n t of t h e s e c o n c e p t s — t h e r e w o u l d r e m a i n s c e p t i c i s m a b o u t internalli/ justified belief. S o t h e r e w o u l d b e n o real g a i n . It is just a s c h a l l e n g i n g to b e told that w e h a v e available to u s n o c o n v i n c i n g r e a s o n s for belief in the physical w o r l d , a s to b e told that w e d o n o t h a v e k n o w l e d g e of s u c h a w o r l d . ) W h i l e m a n y c o n t e m p o r a r y writers h a v e t h o u g h t that a shift to a reliabilist c o n c e p t i o n of k n o w l e d g e h a s great s i g n i f i c a n c e for e p i s t e m o l o g y , I d i s a g r e e , e x c e p t as r e g a r d s t h e possibility of i n n a t e k n o w l e d g e . In particular, w e still face t h e p r o b l e m of s c e p t i c i s m . T o c o n c e d e that t h i s is s o n e e d n o t , h o w e v e r , i m p l y a r e t r e a t t o w a r d s p h e n o m e n a l i s m . F o r w h a t w e m a y surely b e c e r t a i n o f is that w e at l e a s t s e e m to b e p r e s e n t e d w i t h an a r r a y of o b j e c t s in t h r e e - d i m e n s i o n a l s p a c e . ( O f c o u r s e , to b e certain of t h i s , w e h a v e to b e g r a n t e d an a d e q u a t e g r a s p of t h e c o n c e p t s that w e u s e to d e s c r i b e that a p p e a r a n c e . But t h e n a similar c o n c e s s i o n m u s t in a n y c a s e b e g r a n t e d to p h e n o m e n a l i s m . It a p p e a r s that a n y e n q u i r y m u s t t a k e for g r a n t e d that w e p o s s e s s t h e c o n c e p t s u s e d in t h e e x p r e s s i o n of that e n q u i r y . ) T h e r e is t h e n n o t h i n g to force u s to c o n c e d e that t h e b a s i s of e p i s t e m o l o g y m u s t b e d e s c r i p t i o n s of s e n s e - d a t a . R a t h e r , w e m a y take as o u r s t a r t i n g p o i n t that w e at least s e e m t o p e r c e i v e a p h y s i c a l w o r l d , a n d that m a n y of o u r beliefs at least p u r p o r t to c o n c e r n t h e d i s t r i b u t i o n of o b j e c t s w i t h i n that w o r l d . O u r task is t o d i s c o v e r w h e t h e r w e c a n p r o v i d e sufficient r e a s o n for t h i n k i n g t h a t m o s t of t h o s e b e l i e f s a r e t r u e , p e r c e p t i o n itself b e i n g a reliable m e a n s of acquiring beliefs. W h a t f o r m m a y s u c h r e a s o n s t a k e ? Is o u r t a s k to deduce t h e e x i s t e n c e of t h e p h y s i c a l w o r l d f r o m t h e e x i s t e n c e a n d n a t u r e of o u r p e r c e p t u a l b e l i e f s ? If s o , t h e n t h e t a s k is a h o p e l e s s o n e . F o r w e h a v e a l r e a d y c o n c e d e d that it is c o n c e p t u a l l y p o s s i b l e t h a t


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our beliefs and experiences should be just as they are, while t h e r e is i n fact n o p h y s i c a l reality c o r r e s p o n d i n g to t h e m . T h i s m e a n s t h a t t h e r e c a n b e n o valid a r g u m e n t f r o m t h e f o r m e r (our p e r c e p t u a l e x p e r i e n c e ) to t h e latter ( t h e w o r l d ) . F o r a valid a r g u m e n t is p r e c i s e l y o n e for w h i c h it is impossible that t h e p r e m i s s e s s h o u l d b e t r u e w h i l e t h e c o n c l u s i o n is false. ( A n d e v e n if t h e r e c o u l d b e s u c h an a r g u m e n t , t w o p r o b l e m s w o u l d r e m a i n : first, to give a n a t u r a l e x p l a n a t i o n of h o w r e a s o n c a n p o s s e s s s u c h p o w e r , w h i c h is t h e e m p i r i c i s t c h a l l e n g e ; a n d , s e c o n d l y , to s h o w w h y t h e d e m o n , or the fact that I a m d r e a m i n g , m a y n o t b e m a k i n g m e g o w r o n g in m y very u s e of r e a s o n . ) S o if r e a s o n s for belief in t h e physical w o r l d had to c o n s i s t of d e d u c t i v e a r g u m e n t s , t h e n w e s h o u l d b e faced with a sceptical c o n c l u s i o n . T a k i n g for g r a n t e d o n l y that t h e r e a p p e a r s to u s to b e a p h y s i c a l w o r l d , w e c o u l d n o t k n o w o u r s e l v e s to k n o w t h a t t h e r e is s u c h a w o r l d . H o w e v e r , w h y s h o u l d it b e m a i n t a i n e d that r e a s o n s for belief h a v e to t a k e t h e f o r m of d e d u c t i v e l y valid a r g u m e n t s ? W h y should reasons not include non-deductive arguments, such as i n f e r e n c e to t h e b e s t e x p l a n a t i o n of a g i v e n p h e n o m e n o n ? It is e a s y to u n d e r s t a n d w h y a traditional e m p i r i c i s t s h o u l d p l a c e r e s t r i c t i o n s o n a l l o w a b l e r e a s o n s for belief. For s u c h a n e m p i r i c i s t is c o m m i t t e d to t h e t h e s i s that all k n o w l e d g e m u s t b e c o n s t r u c t e d o n a t w o f o l d b a s i s o n l y : t h e data of i m m e d i a t e e x p e r i e n c e , t o g e t h e r w i t h analytic t r u t h s , i n c l u d i n g t h o s e e m b o d i e d in d e d u c t i v e a r g u m e n t s . ( T h e s e latter t h e y u n d e r s t a n d to b e c o n c e r n e d m e r e l y w i t h r e l a t i o n s b e t w e e n t h e i d e a s that w e d e r i v e f r o m e x p e r i e n c e . ) H e n c e d e d u c t i v e a r g u m e n t , a n d o n l y d e d u c t i v e a r g u m e n t , m a y b e t a k e n for g r a n t e d at t h e o u t s e t a s a m e t h o d for p r o v i d i n g r e a s o n s for belief. W i t h n a t i v i s m a l l o w e d t o b e a possibility, t h e s i t u a t i o n t a k e s o n a d i f f e r e n t a s p e c t . F o r it m a y t h e n b e that n o n - d e d u c t i v e p r i n c i p l e s o f b e l i e f f o r m a t i o n , particularly i n f e r e n c e to t h e b e s t explanation, are an innately given part of o u r cognitive a p p a r a t u s . I n d e e d , w e s a w in c h a p t e r 7 that t h e y v e r y likely a r e . I n w h i c h c a s e t h e s e p r i n c i p l e s will c o u n t as f o u n d a t i o n a l , a l o n g s i d e o u r p e r c e p t i o n s a n d p e r c e p t u a l b e l i e f s . B u t this is n o t s u f f i c i e n t to s h o w , a s y e t , t h a t w e m a y m a k e free u s e o f i n f e r e n c e to t h e b e s t e x p l a n a t i o n in e p i s t e m o l o g y . O n e r e a s o n for t h i s is t h a t t h e q u e s t i o n w h e t h e r or n o t s u c h a p r i n c i p l e of

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i n f e r e n c e is i n n a t e is an e m p i r i c a l o n e , n e e d i n g to b e s e t t l e d b y t h e sorts of c o n s i d e r a t i o n a d d u c e d in c h a p t e r 7. S o w e c a n n o t k n o w that the p r i n c i p l e is f o u n d a t i o n a l until w e h a v e p r o v i d e d s o m e e v i d e n c e of it. B u t s u c h e v i d e n c e will very likely p r e s u p p o s e that w e c a n h a v e k n o w l e d g e of t h e p h y s i c a l w o r l d , w h i c h is precisely w h a t is in q u e s t i o n . M o r e o v e r , t h e s a m e p o i n t can b e m a d e h e r e that w e i n s i s t e d on in c o n n e c t i o n w i t h o u r p e r c e p t u a l b e l i e f s . T o say that a p r i n c i p l e of i n f e r e n c e is i n n a t e l y g i v e n is to say that it b e l o n g s to the f o u n d a t i o n s of o u r first-order s y s t e m of beliefs. A n d if that p r i n c i p l e is in fact g e n e r a l l y reliable, a n d the b e l i e f s f o r m e d t h r o u g h its u s e a r e in fact t r u e , t h e n it will c o n t r i b u t e to o u r firsto r d e r k n o w l e d g e . But it d o e s n o t follow that w e m a y take that p r i n c i p l e for g r a n t e d w h e n w e c o m e to e n q u i r e w h a t w e m a y k n o w o u r s e l v e s to k n o w . S i n c e it is by n o m e a n s s e l f - e v i d e n t that i n f e r e n c e to the b e s t e x p l a n a t i o n is a reliable m e t h o d of a c q u i r i n g b e l i e f s , t h e r e is a q u e s t i o n m a r k o v e r its s t a t u s w h e n w e c o m e to d o e p i s t e m o l o g y , just as t h e r e is a q u e s t i o n m a r k o v e r t h e s t a t u s of o u r first-order p e r c e p t u a l b e l i e f s . W e h a v e n o o p t i o n b u t to a t t e m p t to justify o u r reliance o n s u c h a p r i n c i p l e , e v e n if w e k n o w it to b e i n n a t e . In t h e final c h a p t e r of this b o o k I shall a t t e m p t s u c h a j u s t i f i c a t i o n , m a k i n g crucial u s e of the c o n c e s s i o n of n a t i v i s m . B u t first let us c o n s i d e r w h e t h e r the p r i n c i p l e of i n f e r r i n g to the b e s t e x p l a n a t i o n c o u l d in a n y c a s e h e l p u s to o v e r c o m e s c e p t i c i s m a b o u t t h e physical w o r l d . F o r if it w o u l d n o t b e of a n y h e l p , t h e n t h e r e is little p o i n t in d i s c u s s i n g w h e t h e r or n o t that p r i n c i p l e c a n b e j u s t i f i e d . Let u s t h e r e f o r e p r o c e e d for t h e r e m a i n d e r of this c h a p t e r on t h e a s s u m p t i o n that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is j u s t i f i e d . T h i s a s s u m p t i o n will b e v i n d i c a t e d in t h e c h a p t e r that f o l l o w s .

Inferring to the Best Explanation W h a t w e n e e d to d e c i d e , in effect, is w h e t h e r t h e h y p o t h e s i s of o u r reliable p e r c e p t i o n of a p h y s i c a l w o r l d p r o v i d e s t h e b e s t a v a i l a b l e e x p l a n a t i o n of o u r p e r c e p t u a l e x p e r i e n c e , a n d of t h e e x i s t e n c e of o u r first-order p e r c e p t u a l b e l i e f s . T h e r e a r e o n l y f o u r c a n d i d a t e h y p o t h e s e s that w e n e e d to c o n s i d e r .


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T h e first is that t h e r e is i n d e e d a p h y s i c a l w o r l d , a n d that it is a reliable c a u s e of o u r p e r c e p t u a l b e l i e f s . A c c o r d i n g to this h y p o t h e s i s , t h e e x p l a n a t i o n for t h e fact that t h e r e s e e m s to b e a r o o m full of p e o p l e in front of m e , a n d of m y c o n s e q u e n t belief that t h e r e is, is that t h e r e really is a r o o m full of p e o p l e that c a u s e s m y e x p e r i e n c e . L e t u s call this ' t h e realist h y p o t h e s i s ' . T h e s e c o n d h y p o t h e s i s also m a i n t a i n s that t h e r e is a p h y s i c a l w o r l d , b u t d o e s n o t s u p p o s e that this w o r l d is a reliable c a u s e of o u r beliefs. A c c o r d i n g to this h y p o t h e s i s , t h e r e m a y i n d e e d b e s u c h t h i n g s as r o o m s a n d p e o p l e , b u t t h e e x p l a n a t i o n for t h e fact that I s e e m to s e e a r o o m full of p e o p l e m a y be s o m e q u i t e u n r e l a t e d physical s i t u a t i o n , s u c h a s that s o m e s c i e n t i s t s a r e s t i m u l a t i n g t h e visual c e n t r e of m y b r a i n , w h i c h is in fact floating in a vat of c h e m i c a l s in their l a b o r a t o r y . Let us call this ' t h e brain in t h e vat h y p o t h e s i s ' . T h e third h y p o t h e s i s m a i n t a i n s that t h e r e is n o p h y s i c a l w o r l d , a n d n o c a u s e of o u r e x p e r i e n c e s o u t s i d e o u r o w n p s y c h o l o g y . A c c o r d i n g to this h y p o t h e s i s , o u r e x p e r i e n c e is o n e gigantic h a l l u c i n a t i o n . T h e e x p l a n a t i o n for t h e fact that I s e e m to s e e a r o o m full of p e o p l e will t h e n b e s o m e u n k n o w n f e a t u r e of m y p s y c h o l o g y , w h i c h results in m e h a v i n g this e x p e r i e n c e n o w , r a t h e r t h a n a n y o t h e r o n e . T h i s m i g h t b e called ' t h e d r e a m hypothesis'. T h e final h y p o t h e s i s is again that t h e r e is n o p h y s i c a l w o r l d , b u t that o u r e x p e r i e n c e is c a u s e d by s o m e n o n - p h y s i c a l fact i n d e p e n d e n t of o u r m i n d s . For e x a m p l e , t h e e x p l a n a t i o n for t h e fact t h a t I s e e m to s e e a r o o m full o f p e o p l e m a y be that t h e r e is a n a l l - p o w e r f u l d e m o n w h o d e c i d e s to c a u s e m e to h a v e j u s t s u c h an e x p e r i e n c e . T h i s m i g h t as w e l l b e called ' t h e d e m o n hypothesis'. W h i c h of t h e s e available h y p o t h e s e s p r o v i d e s t h e b e s t e x p l a n a t i o n o f m y e x p e r i e n c e , a n d of m y p e r c e p t u a l beliefs? P l a i n l y , I t h i n k , t h e realist h y p o t h e s i s . T h i s c a n s u p p l y a d e t a i l e d a n d h i g h l y s o p h i s t i c a t e d e x p l a n a t i o n of t h e c o u r s e of m y e x p e r i e n c e , at t h e s a m e t i m e w a r r a n t i n g s u b j u n c t i v e s a b o u t w h a t I w o u l d e x p e r i e n c e w e r e I to b e differently s i t u a t e d , a n d counterfactuals about what I would have experienced had I been d i f f e r e n t l y s i t u a t e d in t h e p a s t . T h i s h y p o t h e s i s c a n e x p l a i n n o t o n l y t h e b a r e fact that I s e e m to s e e a r o o m full of p e o p l e , b u t a l s o t h e details of w h a t I s e e m to s e e in t e r m s of t h e details of m y

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p h y s i c a l o r i e n t a t i o n a n d t h e d i s t r i b u t i o n of p e o p l e in t h e r o o m . It c a n also p r e d i c t that I w o u l d s e e m to s e e a largely e m p t y c o r r i d o r if I w e r e to l e a v e the r o o m , a n d that I w o u l d h a v e b e e n s e e m i n g to see s u c h a c o r r i d o r if I h a d s t o p p e d j u s t b e f o r e I c a m e i n t o t h e r o o m . S o t h e h y p o t h e s i s h a s all t h e h a l l m a r k s of a g o o d e x p l a n a t o r y t h e o r y : it p r o v i d e s a s i m p l e , b u t p o w e r f u l l y p r e dictive, e x p l a n a t i o n of the p h e n o m e n a . All t h e o t h e r t h r e e h y p o t h e s e s , in c o n t r a s t , a r e l a m e n t a b l y w e a k . T h e d r e a m h y p o t h e s i s m a y b e d i s m i s s e d straight a w a y , precisely b e c a u s e it m a k e s n o a t t e m p t to e x p l a i n t h e details of my e x p e r i e n c e . T h e brain in the vat h y p o t h e s i s , l i k e w i s e , is i n c a p a b l e of p r o v i d i n g detailed e x p l a n a t i o n s . For if m y e x p e r i e n c e of a r o o m full of p e o p l e is d e p e n d e n t u p o n the w h i m of a n e x p e r i m e n t e r , t h e n I c a n n o t explain in detail w h y I h a v e t h e e x p e r i e n c e s that I d o . N o r can I predict w h a t I shall e x p e r i e n c e n e x t , n o r say w h a t I m i g h t h a v e e x p e r i e n c e d in o t h e r c i r c u m stances. T h e d e m o n hypothesis, too, while being ontologically s i m p l e (it only r e q u i r e s u s to p o s t u l a t e a s i n g l e t h i n g o u t s i d e o u r m i n d s ) , is, as it s t a n d s , lacking in p r e d i c t i v e p o w e r . For w h o k n o w s w h a t t h e d e m o n m i g h t c a u s e m e to e x p e r i e n c e n e x t ? The d e m o n a n d b r a i n in the vat h y p o t h e s e s a l s o e x p l a i n l e s s b e c a u s e t h e y l e a v e t h e d e m o n ' s d e c i s i o n s (or t h o s e of t h e e x p e r i m e n t e r ) t h e m s e l v e s u n e x p l a i n e d . E x p l a n a t i o n will c o m e to an e n d with s u c h c l a i m s a s that t h e d e m o n c h o o s e s that it s h o u l d a p p e a r to m e that t h e r e is a r o o m full of p e o p l e . In c o n t r a s t , t h e h y p o t h e s i s of reliable p e r c e p t i o n c a n e x p l a i n n o t o n l y w h y I a m h a v i n g s u c h a n e x p e r i e n c e ( T h e r e really are p e o p l e p r e s e n t ' ) , b u t also w h a t d o e s t h e e x p l a i n i n g ( ' T h e y h a v e c o m e to listen to m e l e c t u r e ' ) . T h e d e m o n a n d b r a i n in t h e vat h y p o t h e s e s also h a v e l e s s c o h e r e n c e , in that t h e y e m p l o y s e p a r a t e p r i n c i p l e s w h e r e t h e h y p o t h e s i s of reliable p e r c e p t i o n c a n m a k e u s e of a s i n g l e set of l a w s . For e x a m p l e , a p p a r e n t m o t i o n c a n b e e x p l a i n e d , o n t h e realist h y p o t h e s i s , e i t h e r b y m o v e m e n t of t h e o b j e c t p e r c e i v e d , o r b y m o v e m e n t of t h e p e r c e i v e r , t h e s a m e s e t o f p h y s i c a l p r i n c i p l e s b e i n g i n v o l v e d in e i t h e r c a s e . B u t o n t h e d e m o n h y p o t h e s i s , w e s h o u l d h a v e to s u p p o s e that t h e r e a r e t h r e e distinct p r i n c i p l e s that t h e d e m o n c h o o s e s to e m p l o y . O n t h e o n e h a n d h e s o m e t i m e s c h o o s e s that it s h o u l d a p p e a r t o m e t h a t t h i n g s a r e in m o t i o n . O n t h e o t h e r h a n d , in a s i t u a t i o n w h e r e h e


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would h a v e d e c i d e d not t o c a u s e a n a p p e a r a n c e of m o t i o n , if I t h i n k to m y s e l f 'I shall m o v e ' , t h e n t h e d e m o n docs c a u s e s u c h an a p p e a r a n c e . T h e r e a r e also rare c a s e s in w h i c h , w h e r e h e w o u l d o t h e r w i s e h a v e c a u s e d an a p p e a r a n c e of m o t i o n , if I t h i n k to m y s e l f T shall m o v e ' , t h e n h e d e c i d e s not to c a u s e s u c h an a p p e a r a n c e (for e x a m p l e , c a s e s w h e r e I w a l k parallel to a m o v i n g o b j e c t in a n o t h e r w i s e d a r k e n e d r o o m , s o that t h e o b j e c t appears stationary). T h e o n l y r e c o u r s e for t h e d e m o n h y p o t h e s i s (as for the brain in the vat h y p o t h e s i s ) is to s u p p o s e that for s o m e r e a s o n the d e m o n (or t h e e x p e r i m e n t e r ) c h o o s e s to c a u s e m e to h a v e e x p e r i e n c e s e x a c t l y as if t h e r e w e r e t h e sort of physical world 1 intuitively b e l i e v e t h e r e to b e . T h e o n l y w a y for t h e d e m o n h y p o t h e s i s to h a v e t h e e x p l a n a t o r y a n d p r e d i c t i v e p o w e r of realism is for it to b e cast in the form ' T h e d e m o n d e c i d e s to give m e e x p e r i e n c e s for w h i c h the b e s t e x p l a n a t i o n w o u l d o t h e r w i s e (before m e n t i o n of t h e d e m o n ) b e . . . ', f o l l o w e d by e v e r y claim of r e a l i s m . T h e n I c a n e x p l a i n not only m y e x p e r i e n c e of a r o o m full of p e o p l e , b u t w h a t d o e s the e x p l a i n i n g : it is b e c a u s e the d e m o n w i s h e s m e to b e l i e v e that t h e r e a r e p e o p l e w h o w a n t to listen to m e l e c t u r e . A n d I can predict that 1 s h o u l d h a v e an e x p e r i e n c e of a largely e m p t y corridor if I w e r e to leave t h e r o o m : it is b e c a u s e t h e d e m o n w i s h e s m e to b e l i e v e that t h e r e are c o r r i d o r s t h a t r e m a i n in e x i s t e n c e w h e n u n o b s e r v e d , a n d that a r e g e n e r a l l y e m p t y d u r i n g lecture h o u r s . A n d s o o n . B u t this n o w r e n d e r s t h e d e m o n h y p o t h e s i s m o r e c o m p l e x t h a n r e a l i s m , s i n c e it c o n t a i n s all t h e latter's c o m p l e x i t y , t o g e t h e r w i t h t h e a d d i t i o n a l s u p p o s i t i o n o f t h e d e m o n a n d his d e c i s i o n s . A l t h o u g h t h e d e m o n h y p o t h e s i s is o n t o l o g i c a l l y s i m p l e r , s i n c e it o n l y p o s t u l a t e s a s i n g l e t h i n g o u t s i d e m y s e l f , it is structurally m o r e c o m p l e x , s i n c e e v e r y s t a t e m e n t w i t h i n r e a l i s m will h a v e t o a p p e a r w i t h i n t h e d e m o n h y p o t h e s i s , p r e c e d e d b y a c l a i m a b o u t t h e d e m o n a n d his d e c i s i o n s . (This m u s t b e s o if t h e latter is to s h a r e t h e f o r m e r ' s p r e d i c t i v e p o w e r . ) A n d it is i m p o r t a n t to see that in a s s e s s i n g e x p l a n a t i o n s it is s t r u c t u r a l , r a t h e r t h a n o n t o l o g i c a l , simplicity that m a t t e r s . T h i s is b e c a u s e , in g i v i n g a n e x p l a n a t i o n o f s o m e p h e n o m e n o n , it is a l w a y s f a c t s r a t h e r t h a n o b j e c t s that d o t h e e x p l a i n i n g . T h e m e r e e x i s t e n c e of r o o m s a n d p e o p l e c a n n o t , for e x a m p l e , e x p l a i n m y e x p e r i e n c e of a r o o m full of p e o p l e ; it is t h e fact t h a t t h e r e a r e

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p e o p l e in a r o o m w i t h i n m y line of v i s i o n that e x p l a i n s . S o w h e n w e a r e told that b e t t e r e x p l a n a t i o n s d o n o t m u l t i p l y entities b e y o n d w h a t is n e c e s s a r y ( w h i c h s o u n d s like a direct e x h o r t a tion to o n t o l o g i c a l s i m p l i c i t y ) , this is o n l y b e c a u s e t h e o r i e s that p o s t u l a t e m o r e k i n d s of t h i n g will a l s o , in g e n e r a l , h a v e to p o s t u l a t e m o r e k i n d s of f a c t — b u t n o t a l w a y s , as t h e c o m p a r i s o n of r e a l i s m with t h e d e m o n h y p o t h e s i s m a k e s clear. A n o t h e r p o i n t is that on the p r e s e n t p r o p o s a l t h e d e m o n h y p o t h e s i s b e c o m e s entirely parasitic u p o n r e a l i s m . T h e o n l y w a y actually to w o r k t h e h y p o t h e s i s is to forget a b o u t t h e d e m o n , a n d to get on with the j o b of c o n s t r u c t i n g the b e s t available v e r s i o n of r e a l i s m . T h i s m e a n s that the d e m o n h y p o t h e s i s , b e s i d e s b e i n g m o r e c o m p l e x , also lacks a n o t h e r v i r t u e of a g o o d e x p l a n a t o r y t h e o r y — t h a t of f r u i t f u l n e s s . O n e of t h e m a r k s of a g o o d t h e o r y , it is g e n e r a l l y a g r e e d , is that it s h o u l d b e fruitful, l e a d i n g to n e w p r e d i c t i o n s that c o u l d n o t p r e v i o u s l y h a v e b e e n m a d e , a n d s u g g e s t i n g n e w lines of r e s e a r c h . Yet in this respect t h e d e m o n h y p o t h e s i s is e n t i r e l y inert. It predicts n o t h i n g w h i c h is not also p r e d i c t e d by r e a l i s m , a n d n o t only d o e s it fail to s u g g e s t n e w a v e n u e s of r e s e a r c h , b u t it is i m p o s s i b l e to do. r e s e a r c h e x c e p t by f o r g e t t i n g t h e d e m o n a n d c o n s t r u c t i n g t h e best t h e o r i e s that o n e can w i t h i n t h e orbit of r e a l i s m . It is clear, t h e n , that the h y p o t h e s i s of reliable p e r c e p t i o n p r o v i d e s o v e r w h e l m i n g l y the b e s t available e x p l a n a t i o n o f the c o u r s e of o u r e x p e r i e n c e , a n d of t h e e x i s t e n c e of o u r p e r c e p t u a l b e l i e f s . ( I shall r e t u r n in t h e n e x t c h a p t e r to t h e sceptical s u g g e s t i o n that t h e d e m o n m a y also b e i n t e r f e r i n g w i t h m y p o w e r s of b e s t e x p l a n a t i o n , l e a d i n g m e to r e j e c t a s w o r s e a h y p o t h e s i s that m a y actually b e b e t t e r . ) It is t h e r e f o r e a m a t t e r of s o m e i m p o r t a n c e to d e c i d e w h e t h e r w e can legitimately rely u p o n i n f e r e n c e to t h e b e s t e x p l a n a t i o n in a t t e m p t i n g to c o m b a t s c e p t i c i s m . If w e c a n , t h e n it w o u l d a p p e a r that t h e sceptic c a n i n d e e d b e a n s w e r e d . B u t b e f o r e t u r n i n g to that t a s k , I p r o p o s e to consider one further objection.

M u s t K n o w l e d g e be Foolproof? T h e o b j e c t i o n is as f o l l o w s . E v e n if it is g r a n t e d that w e m a y s o m e h o w k n o w t h a t i n f e r e n c e to t h e b e s t e x p l a n a t i o n is a


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g e n e r a l l y reliable m e t h o d of a c q u i r i n g b e l i e f s , it is certainly n o t a f o o l p r o o f m e t h o d . O n n o a c c o u n t of t h e m a t t e r will a n i n f e r e n c e to t h e b e s t e x p l a n a t i o n of s o m e p h e n o m e n o n p r o v i d e a n y sort of g u a r a n t e e of t h e t r u t h of t h e c o n c l u s i o n . E v e n if it is g e n e r a l l y reliable, it is also u n d e n i a b l y s o m e t i m e s fallible. S o , e v e n g i v e n that t h e h y p o t h e s i s of reliable p e r c e p t i o n p r o v i d e s t h e b e s t e x p l a n a t i o n of the c o u r s e o f o u r e x p e r i e n c e , it r e m a i n s p o s s i b l e that it s h o u l d b e false. I n d e e d , it r e m a i n s p o s s i b l e that t h e d e m o n h y p o t h e s i s , a l t h o u g h w o r s e (in t e r m s of simplicity, f r u i t f u l n e s s , a n d so o n ) , is in fact t h e c o r r e c t o n e . It m a y t h e n b e o b j e c t e d that o u r belief that w e h a v e k n o w l e d g e of t h e p h y s i c a l w o r l d c a n n o t , o n this b a s i s , c o n s t i t u t e k n o w l e d g e . S i n c e it is not c o m p l e t e l y c e r t a i n , w e c a n n o t really k n o w it. T h i s o b j e c t i o n r e p r e s e n t s a p e r e n n i a l t e m p t a t i o n in p h i l o s o p h y — n a m e l y , to insist that y o u c a n n o t really k n o w a n y t h i n g u n l e s s y o u c a n b e c o m p l e t e l y c e r t a i n of it. S o e v e n if w e h a v e r e a s o n for b e l i e v i n g i n f e r e n c e to t h e b e s t e x p l a n a t i o n to b e g e n e r a l l y reliable, a n d r e a s o n for b e l i e v i n g that w e h a v e k n o w l e d g e of the p h y s i c a l w o r l d , w e c a n n o t p r o p e r l y b e said to know t h e s e t h i n g s , s i n c e w e h a v e n o a b s o l u t e g u a r a n t e e of t h e i r t r u t h . O n this a c c o u n t , n o t h i n g c a n p r o p e r l y c o n s t i t u t e k n o w l e d g e , e x c e p t w h e r e it is i n c o n c e i v a b l e that it s h o u l d b e false, g i v e n t h e e v i d e n c e . ( O r p e r h a p s : e x c e p t w h e r e it is i n c o n c e i v able that it s h o u l d turn out to be f a l s e , g i v e n t h e e v i d e n c e — w h i c h is n o t quite t h e s a m e t h i n g . ) 2

It is w o r t h n o t i n g that w e n e v e r in fact i n s i s t u p o n a b s o l u t e c e r t a i n t y in o u r practical lives, n o m a t t e r h o w m u c h m a y b e at s t a k e . F o r e x a m p l e , i m a g i n e y o u r s e l f a s a j u r o r in a m u r d e r c a s e , in a state that r e t a i n s t h e d e a t h p e n a l t y , a n d i m a g i n e that t h e evidence against the defendant is, as w e say, overwhelming. N e v e r t h e l e s s , as a s c r u p u l o u s p e r s o n , y o u ask y o u r s e l f w h e t h e r y o u really k n o w that t h e d e f e n d a n t is guilty. N o w s u p p o s e that o n e of t h e o t h e r j u r o r s h a s p r o p o s e d a n a l t e r n a t i v e h y p o t h e s i s — n a m e l y , t h a t a g r o u p of s u p e r - i n t e l l i g e n t M a r t i a n s m a y h a v e l a n d e d o n E a r t h u n d e t e c t e d , a n d p l a n t e d all t h e e v i d e n c e a g a i n s t t h e d e f e n d a n t f o r p u r p o s e s k n o w n o n l y to t h e m s e l v e s . T h i s h y p o t h e s i s is c e r t a i n l y a p o s s i b l e o n e , in t h e s a m e w a y that t h e h y p o t h e s i s of t h e o m n i p o t e n t d e m o n i s . It t h e r e f o r e s h o w s that y o u r belief t h a t t h e d e f e n d a n t is guilty is n o t a b s o l u t e l y T h i s s o r t o f p o s s i b i l i t y is e x p l o r e d b y L u d w i g W i t t g e n s t e i n i n On (Oxford: Blackwell, 1969). 2

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c e r t a i n . But plainly this a l t e r n a t i v e p r o p o s a l w o u l d n o t e v e n c a u s e y o u to h e s i t a t e in h a n d i n g d o w n a guilty v e r d i c t , d e s p i t e t h e fact that s o m e o n e ' s life h a n g s in t h e b a l a n c e . W h a t e m e r g e s is that it is far from o b v i o u s w h y w e s h o u l d e v e n p o s s e s s t h e c o n c e p t of k n o w l e d g e , if k n o w l e d g e really did require c o m p l e t e c e r t a i n t y . For this is n o t a c o n c e p t that w e h a v e a n y u s e for in o u r practical lives. I s u p p o s e it m i g h t b e replied that s u c h a c o n c e p t w o u l d h a v e a u s e , as a k i n d of ideal, to w h i c h o u r o r d i n a r y s t a n d a r d s of justification m a y a p p r o x i m a t e but n e v e r attain. But in fact I think that the t e n d e n c y that p h i l o s o p h e r s h a v e , to insist that k n o w l e d g e r e q u i r e s c e r t a i n t y , is based on an illusion, p r o d u c e d by a feature of t h e c o n c e p t of k n o w l e g e that it s h a r e s with m a n y of o u r o t h e r c o n c e p t s — n a m e l y , that it is purpose-relative. Let m e e x p l a i n . N o t i c e that t h e s t a n d a r d s that w e ordinarily insist on for a belief to c o u n t as k n o w l e d g e m a y vary a c c o r d i n g to t h e s e r i o u s n e s s with w h i c h w e take t h e situation in w h i c h t h e q u e s t i o n o f k n o w l e d g e a r i s e s . S u p p o s e , for e x a m p l e , that I a s k y o u , as a casual e n q u i r y , w h e t h e r you k n o w that M a r y will b e at t h e P h i l o s o p h y D e p a r t m e n t party. Y o u reply that y o u d o k n o w this, b e c a u s e s h e told you that s h e w o u l d be t h e r e . In t h e c o n t e x t , I think w e s h o u l d ordinarily b e i n c l i n e d to a l l o w that you d o k n o w that M a r y will be at the p a r t y . But n o w i m a g i n e a n exactly similar e x c h a n g e taking place in the c o n t e x t of a m u r d e r trial. 1 a s k y o u w h e t h e r y o u k n o w that M a r y is t h e m u r d e r e r , a n d y o u reply that y o u d o k n o w t h i s , b e c a u s e s h e told y o u s o . E v e n g r a n t i n g y o u r s i n c e r i t y , it is plain that w h a t y o u s a y w o u l d be i n s u f f i c i e n t to c o n v i c t h e r . H e r e , s i n c e a life or a life s e n t e n c e h a n g s in the b a l a n c e , w e w o u l d insist o n g r e a t e r j u s t i f i c a t i o n t h a n this b e f o r e a l l o w i n g that y o u h a v e k n o w l e d g e . T h i s sort of variability is easily e x p l a i n e d if ' k n o w s ' m e a n s 'is a t r u e belief that is reliably e n o u g h g r o u n d e d for t h e p u r p o s e s in h a n d ' . M o r e o v e r , s i n c e t h e c o n t e x t s in w h i c h w e e m p l o y a c o n c e p t of k n o w l e d g e m a y c o n t a i n a variety o f d i f f e r e n t p u r p o s e s a n d i n t e r e s t s of v a r y i n g i m p o r t a n c e , it is e a s y t o s e e that o u r n e e d for s u c h a c o n c e p t is fulfilled b y t h e p o s s e s s i o n of j u s t s u c h a purpose-relative c o n c e p t . 3

It is a r g u a b l e that a g r e a t m a n y of o u r c o n c e p t s a r e p u r p o s e relative in p r e c i s e l y this sort of w a y . C o n s i d e r , for e x a m p l e , t h e F o r a d i s c u s s i o n of t h e r e l a t i o n s h i p b e t w e e n c o n c e p t s a n d h u m a n p u r p o s e s , s e e m y ' C o n c e p t u a l P r a g m a t i s m ' , Synthese, 1 9 8 7 . 3


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t e r m 'flat'. S u p p o s e t h a t y o u a r e a f a r m e r , w h o o w n s a n u m b e r of fields that are at p r e s e n t u n d e r g r a s s . Y o u a r e first a p p r o a c h e d b y s o m e o n e f r o m y o u r local Territorial A r m y , w h o is l o o k i n g for a flat field o n w h i c h to p r a c t i s e m a n o e u v r e s . Y o u point to a p a r t i c u l a r field a n d say ' T h a t o n e is flat'. O n a n o t h e r o c c a s i o n y o u a r e a p p r o a c h e d by y o u r local b o w l s c l u b , w h o a r e l o o k i n g for a flat field o n w h i c h to play w h i l e their b o w l i n g g r e e n is u n d e r r e p a i r . Y o u p o i n t to t h e v e r y s a m e field a n d s a y ' T h a t o n e is n o t flat'. O n b o t h o c c a s i o n s , s u r e l y , y o u m i g h t say s o m e t h i n g t r u e . T h e e x p l a n a t i o n for this is that 'flat' m e a n s 'is flatter t h a n e n o u g h t h i n g s of t h e kind in q u e s t i o n for t h e p u r p o s e s in h a n d ' . W h e r e t h e p u r p o s e s differ, s o d o e s t h e correct a p p l i c a t i o n of t h e c o n c e p t . N o w t h e i m p o r t a n t p o i n t to n o t i c e is t h a t , w h e r e t h e r e a r e no p u r p o s e s in h a n d , t h e s t a n d a r d s for a p p l y i n g s u c h c o n c e p t s a r e apt to b e c o m e u n l i m i t e d l y h i g h . T h i s m a y b e b e c a u s e o n e t h e n naturally s e t s s t a n d a r d s that w o u l d be a p t for a n y conceivable p u r p o s e . For e x a m p l e , s u p p o s e that I a s k , in the c o n t e x t of a theoretical d i s c u s s i o n of s c e p t i c i s m , w h e r e n o p a r t i c u l a r practical p r o j e c t is in h a n d , 'Is this table really flat?' T h e r e w o u l d b e a very n a t u r a l t e n d e n c y to r e p l y in t h e n e g a t i v e . Y o u w o u l d i m m e d i a t e l y t h i n k , for e x a m p l e , that t h e s u r f a c e of t h e table is b o u n d to c o n t a i n slight irregularities, e v e n if t h e y are u n d e t e c t a b l e to s i g h t o r t o u c h . T h u s , w i t h n o particular p u r p o s e in h a n d , y o u a r e i n c l i n e d to insist that n o t h i n g can really b e flat u n l e s s it is absolutely flat. S i m i l a r l y , t h e n , in c o n n e c t i o n w i t h t h e c o n c e p t of k n o w l e d g e . W h e n w e a s k , o u t s i d e t h e c o n t e x t of a n y practical p u r p o s e or p r o j e c t , ' D o w e really k n o w t h a t s u c h - a n d - s u c h ? ' , t h e r e is a very n a t u r a l t e n d e n c y to d e n y it. T h i s e x p l a i n s t h e i m p u l s e to r e j e c t o u r c l a i m to h a v e k n o w l e d g e of t h e p h y s i c a l w o r l d , e v e n g i v e n that t h e h y p o t h e s i s of reliable p e r c e p t i o n p r o v i d e s o v e r w h e l m i n g l y t h e b e s t e x p l a n a t i o n of t h e c o u r s e of o u r e x p e r i e n c e . B u t , for all t h a t , o u r b e l i e f t h a t w e h a v e k n o w l e d g e of p h y s i c a l o b j e c t s m a y b e w e l l e n o u g h j u s t i f i e d to c o u n t a s k n o w l e d g e for a n y p u r p o s e that w e m i g h t actually h a v e . I t h e r e f o r e c o n c l u d e t h a t , if w e c a n s o m e h o w j u s t i f y o u r r e l i a n c e u p o n i n f e r e n c e to t h e b e s t e x p l a n a t i o n , s c e p t i c i s m a b o u t t h e p h y s i c a l w o r l d will h a v e b e e n d e c i s i v e l y r e f u t e d .

12 Knowledge by Best Explanation IN this final c h a p t e r I shall c o n s i d e r w h e t h e r t h e c o n c e s s i o n o f n a t i v i s m w o u l d e n a b l e an e m p i r i c i s t to s o l v e t h e p r o b l e m of i n d u c t i o n , a n d of j u s t i f y i n g n o n - d e d u c t i v e m o d e s of a r g u m e n t generally.

Preliminaries to a P r o b l e m A s I n o t e d in the last c h a p t e r , if o u r p e r c e p t u a l b e l i e f s are in fact b o t h t r u e a n d reliably c a u s e d , t h e n t h e y will c o n s t i t u t e firsto r d e r k n o w l e d g e of t h e w o r l d . I a l s o a r g u e d that t h e s u p p o s i t i o n that t h e y are reliably c a u s e d b y p h y s i c a l o b j e c t s is o v e r w h e l m i n g l y t h e b e s t e x p l a n a t i o n of their e x i s t e n c e . N o w if w e c o u l d s o m e h o w k n o w that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is a g e n e r a l l y reliable p r o c e s s , t h e n w e c o u l d also k n o w that o u r p e r c e p t u a l beliefs a r e largely t r u e . In that c a s e w e s h o u l d h a v e s e c o n d - o r d e r k n o w l e d g e also. W e s h o u l d b e able to k n o w that w e h a v e k n o w l e d g e of t h e p h y s i c a l w o r l d , t h u s a v o i d i n g scepticism. A g o o d deal m o r e is at s t a k e in this c h a p t e r t h a n t h i s , h o w e v e r . F o r i n f e r e n c e to t h e b e s t e x p l a n a t i o n is also i m p l i c a t e d in t h e v a s t s u p e r s t r u c t u r e of belief that w e e r e c t o n t h e b a s i s of o u r p e r c e p t u a l b e l i e f s , i n c l u d i n g m a n y of t h e b e l i e f s of c o m m o n s e n s e , a s w e l l a s t h o s e of s c i e n c e . F o r e x a m p l e , m a n y of m y beliefs a b o u t t h e p a s t p r e s u p p o s e t h e reliability of m e m o r y . I b e l i e v e that m e m o r y is g e n e r a l l y reliable, in t u r n , b e c a u s e t h e h y p o t h e s i s that it is s o p r o v i d e s t h e b e s t e x p l a n a t i o n of t h e w a y in w h i c h m y m e m o r i e s c o h e r e w i t h t h o s e of o t h e r p e o p l e , a n d w i t h o t h e r traces of t h e p a s t , s u c h a s p h o t o g r a p h s a n d w r i t t e n r e c o r d s . I n t h e s a m e w a y , m a n y of m y b e l i e f s a b o u t t h e f u t u r e

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( s u c h as t h a t m y h o u s e will b e w h e r e I e x p e c t it to b e w h e n I r e t u r n h o m e in t h e e v e n i n g ) p r e s u p p o s e that I i n h a b i t a g e n e r a l l y r e g u l a r , s t a b l e w o r l d , in w h i c h m o s t e v e n t s h a p p e n in a c c o r d a n c e w i t h p r e d i c t a b l e p a t t e r n s . I h o l d this belief, in its t u r n , b e c a u s e it p r o v i d e s t h e b e s t available e x p l a n a t i o n of t h e regularities of t h e p a s t . E v e n m y belief that m y c h a i r c o n t i n u e s to exist w h e n I t u r n m y b a c k o n it is j u s t i f i e d , if it is, b e c a u s e it p r o v i d e s t h e b e s t available e x p l a n a t i o n for t h e fact that t h e chair is still t h e r e w h e n I t u r n a r o u n d a g a i n . A n d , of c o u r s e , m y b e l i e f s c o n c e r n i n g t h e theoretical e n t i t i e s of s c i e n c e , s u c h a s e l e c t r o n s , a r e h e l d b e c a u s e the h y p o t h e s i s of their e x i s t e n c e p r o v i d e s t h e b e s t e x p l a n a t i o n of a v a r i e t y of e x p e r i m e n t a l d a t a . All t h i s , t o o , w o u l d b e v i n d i c a t e d , if n o n - d e d u c t i v e m o d e s of a r g u m e n t c o u l d b e j u s t i f i e d . In that c a s e w e s h o u l d n o t o n l y b e a b l e to d e f e a t t h e s c e p t i c a b o u t t h e p h y s i c a l w o r l d . W e s h o u l d also b e in a p o s i t i o n to d e f e a t the k i n d of sceptic w h o , w h i l e a l l o w i n g that w e k n o w of the e x i s t e n c e of the p h y s i c a l w o r l d , a n d o f t h e o b j e c t s w e are c u r r e n t l y p e r c e i v i n g , w o u l d d e n y that w e h a v e a n y k n o w l e d g e of t h e p a s t , t h e f u t u r e , r e g i o n s of s p a c e n o t c u r r e n t l y u n d e r o u r o b s e r v a t i o n , or s u c h t h i n g s a s e l e c t r o n s , w h i c h a r e t o o s m a l l to b e p e r c e i v e d . F o r in all t h e s e c a s e s o u r b e l i e f s rely, in o n e w a y or a n o t h e r , o n i n f e r e n c e to t h e b e s t explanation. I a m g o i n g to s u g g e s t that t h e c o n c e s s i o n of a certain sort of n a t i v i s m m a y e n a b l e t h e e m p i r i c i s t to justify r e a l i s m a b o u t o u r k n o w l e d g e of t h e p h y s i c a l w o r l d . H o w e v e r , o n e o b v i o u s p r o b l e m in a t t e m p t i n g to m a k e u s e of n a t i v i s m in c o m b a t i n g t h e s c e p t i c is that m o s t o f t h e a r g u m e n t s g i v e n in s u p p o r t of n a t i v i s m s e e m to p r e s u p p o s e that t h e r e is a p h y s i c a l w o r l d , a n d that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is a reliable m e t h o d of a c q u i r i n g beliefs a b o u t that w o r l d . In t h e final s e c t i o n of c h a p t e r 7, for e x a m p l e , w e c o n c l u d e d that o u r c o n c e p t of b e s t e x p l a n a tion is v e r y likely i n n a t e , s i n c e it d o e s n o t a p p e a r to b e explicitly t a u g h t , a n d s i n c e it is h a r d t o s e e h o w it c o u l d b e a c q u i r e d f r o m e x p e r i e n c e . In effect, w e a r g u e d t h a t t h e b e s t available e x p l a n a tion of o u r p o s s e s s i o n of t h e c o n c e p t best explanation is that it is i n n a t e . W e t h e n i m m e d i a t e l y f a c e t h e c h a r g e of circularity, if w e try t o m a k e u s e of t h e c o n c l u s i o n o f this a r g u m e n t in t r y i n g to j u s t i f y o u r r e l i a n c e u p o n i n f e r e n c e to t h e b e s t e x p l a n a t i o n . H o w e v e r , I propose to set this problem to o n e side for the

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m o m e n t . I shall f o c u s initially o n t h e q u e s t i o n w h e t h e r t h e i n n a t e n e s s of o u r c o n c e p t of b e s t e x p l a n a t i o n c o u l d in a n y c a s e h e l p w i t h t h e p r o b l e m of j u s t i f i c a t i o n . I shall r e t u r n to t h e c h a r g e of circularity in a later s e c t i o n . M o s t of t h e d i s c u s s i o n s s i n c e H u m e , of a t t e m p t s to justify n o n - d e d u c t i v e p a t t e r n s of r e a s o n i n g , h a v e f o c u s e d u p o n i n d u c t i o n — t h a t is, o n a r g u m e n t s w h o s e p r e m i s s e s t a k e t h e f o r m ' W i t h i n o u r o b s e r v a t i o n all A s h a v e b e e n B s ' a n d w h o s e c o n c l u s i o n s h a v e e i t h e r t h e f o r m ' T h e r e f o r e all A s are B s ' or t h e f o r m ' T h e r e f o r e the n e x t A will b e a B ' . B u t , as w e n o t e d in c h a p t e r 7, i n d u c t i o n itself s h o u l d p r o p e r l y b e u n d e r s t o o d as a n i n s t a n c e of the w i d e r c a t e g o r y of i n f e r e n c e to the b e s t e x p l a n a t i o n . A c c o r d i n g l y , in t h e n e x t s e c t i o n I shall briefly o u t l i n e t h e traditional p r o b l e m of i n d u c t i o n , a n d e x p l a i n t h e m a i n a t t e m p t s t h a t h a v e b e e n m a d e to s o l v e that p r o b l e m . In e a c h c a s e I shall s h o w h o w t h o s e a t t e m p t s h a v e a n a l o g u e s in t h e a t t e m p t to justify i n f e r e n c e to t h e b e s t e x p l a n a t i o n . N o n e of t h e s e a t t e m p t s , a s t h e y s t a n d , will p r o v e s u c c e s s f u l .

T h e Problem of Induction T h e first p o i n t to n o t i c e a b o u t i n d u c t i v e a r g u m e n t s is that t h e y are n o t d e d u c t i v e l y valid. F r o m the fact that all o b s e r v e d A s h a v e , s o far, b e e n B , it certainly d o e s n o t follow that all A s are B s . It is a l w a y s at least c o n c e i v a b l e that t h e v e r y n e x t A w e o b s e r v e , or i n d e e d all the r e m a i n i n g A s , will t u r n out n o t to b e B . N o r d o e s it f o l l o w f r o m o u r o b s e r v a t i o n s that probably all A s a r e B s , e x c e p t in t h o s e rare c a s e s w h e r e t h e set of A s is finite a n d w e h a v e a l r e a d y o b s e r v e d a s u b s t a n t i a l p e r c e n t a g e of t h e m . S o w e c e r t a i n l y c a n n o t validly d e d u c e that all A s are B s (or e v e n that t h e n e x t A will p r o b a b l y b e B) o n t h e b a s i s of o u r p a s t o b s e r v a t i o n s . F o r a valid a r g u m e n t is p r e c i s e l y o n e w h e r e it is i n c o n c e i v a b l e t h a t t h e p r e m i s s e s s h o u l d b e true w h i l e t h e c o n c l u s i o n is false. S u p p o s e w e c o u l d k n o w that n a t u r e is b r o a d l y u n i f o r m — t h a t t h e s a m e g e n e r a l l a w s a n d p r i n c i p l e s will o b t a i n in all r e g i o n s of s p a c e a n d t i m e , a n d t h a t , a s H u m e p u t s it, t h e f u t u r e will broadly resemble the past. T h e n we would k n o w that most r e g u l a r i t i e s i n n a t u r e a r e p r o j e c t a b l e . In w h i c h c a s e t h e i n s e r t i o n


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of this t h e s i s i n t o i n d u c t i v e a r g u m e n t s , as a n extra p r e m i s s , w o u l d t u r n t h e m i n t o d e d u c t i v e l y valid o n e s . T h a t is, f r o m 'AH o b s e r v e d A s h a v e b e e n B s ' , t o g e t h e r w i t h ' M o s t regularities in n a t u r e a r e p r o j e c t a b l e ' , w e c o u l d validly d e d u c e ' P r o b a b l y this regularity is p r o j e c t a b l e , s o p r o b a b l y all A s are B s ' . T h e t r o u b l e , h o w e v e r , c o n c e r n s h o w w e a r e to k n o w that n a t u r e is u n i f o r m . T h e o n l y p l a u s i b l e s o u r c e of o u r k n o w l e d g e of this is itself i n d u c t i v e . T h e o n l y real g r o u n d for c l a i m i n g that n a t u r e is m o s t l y r e g u l a r is that it h a s m o s t l y b e e n s o w i t h i n o u r e x p e r i e n c e in the p a s t . B u t t h e n t h e m o v e f r o m ' N a t u r e h a s m o s t l y b e e n r e g u l a r in t h e p a s t ' to ' N a t u r e is m o s t l y r e g u l a r ' is an i n d u c t i v e o n e , in w h i c h c a s e o u r a r g u m e n t will a p p a r e n t l y h a v e b e e n m o v i n g in circles. I n d u c t i v e a r g u m e n t s a r e n o t d e d u c t i v e l y valid, a n d t h e a t t e m p t to t u r n t h e m i n t o d e d u c t i v e a r g u m e n t s t h r o u g h t h e i n s e r t i o n o f a n extra p r e m i s s a p p e a r s h o p e l e s s . Y e t t h e y d o s e e m to s t a n d in n e e d of j u s t i f i c a t i o n . It certainly is n o t intuitively o b v i o u s that g e n e r a l i z i n g f r o m o b s e r v e d regularities is a reliable w a y of g a i n i n g g e n e r a l k n o w l e d g e of t h e w o r l d . ( A n d e v e n if it were intuitively o b v i o u s , e m p i r i c i s t s w o u l d still d e m a n d a n a t u r a l e x p l a n a t i o n of t h e reliability of s u c h i n t u i t i o n s . ) If o u r task is t o k n o w w h a t w e k n o w , t h e n p l a i n l y w e c a n n o t s i m p l y take the s o u n d n e s s o f i n d u c t i o n for g r a n t e d . O n the c o n t r a r y , if w e are to m a k e u s e of i n d u c t i o n in e p i s t e m o l o g y , w e shall h a v e to give r e a s o n s for t h i n k i n g that i n d u c t i o n is g e n e r a l l y reliable. T h e r e h a v e in fact b e e n o n l y t h r e e m a i n a t t e m p t s to j u s t i f y o u r r e l i a n c e u p o n i n d u c t i o n . T h e s e a r e t h e so-called ' p r a g m a t i c ' , ' a n a l y t i c ' , a n d ' i n d u c t i v e ' p r o p o s a l s r e s p e c t i v e l y . O n l y t h e last t w o of t h e s e n e e d c o n c e r n u s h e r e , for r e a s o n s that I shall n o w briefly e x p l a i n . 1

T h e p r a g m a t i c p r o p o s a l for s o l v i n g t h e p r o b l e m of i n d u c t i o n c o n s i s t s in s o m e v e r s i o n of t h e f o l l o w i n g a r g u m e n t : N a t u r e is e i t h e r r e g u l a r or n o t . If it is r e g u l a r , t h e n i n d u c t i o n will g a i n g e n e r a l k n o w l e d g e for u s b e t t e r t h a n a n y o t h e r m e t h o d . If n a t u r e is n o t r e g u l a r , t h e n no m e t h o d will b e s u c c e s s f u l in a c q u i r i n g g e n e r a l k n o w l e d g e . S o , e i t h e r w a y , F o r e x a m p l e s of e a c h of these, s e e the p a p e r s collected in R. S w i n b u r n e ( e d . ) , The Justification of Induction ( O x f o r d : O x f o r d U n i v e r s i t y P r e s s , 1 9 7 4 ) . 1

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g i v e n t h a t w e w a n t g e n e r a l k n o w l e d g e , it is r a t i o n a l for u s t o employ induction. N o t i c e , h o w e v e r , that s u c h a n a r g u m e n t d o e s n o t p e r m i t u s to c o n c l u d e that i n d u c t i o n is g e n e r a l l y reliable. T h e claim is n o t that i n d u c t i o n is likely to p r o d u c e t r u t h s , b u t m e r e l y that it is m o r e likely to p r o d u c e t r u t h s t h a n a n y a l t e r n a t i v e m e t h o d w e m i g h t follow. T h e p r a g m a t i c p r o p o s a l only e s t a b l i s h e s , at b e s t , that it is r e a s o n a b l e to employ i n d u c t i o n , s i n c e i n d u c t i o n m a y s u c c e e d w h e r e a s n o o t h e r policy will. W h a t w e n e e d , h o w e v e r , is a n a r g u m e n t w h o s e c o n c l u s i o n is that i n d u c t i o n (or r a t h e r t h e w i d e r c a t e g o r y of i n f e r e n c e to t h e b e s t e x p l a n a t i o n ) m a y r e a s o n a b l y b e r e g a r d e d as reliable. For w h a t w e require is k n o w l e d g e of its reliability, if w e a r e to u s e i n f e r e n c e to t h e b e s t e x p l a n a t i o n to g i v e u s k n o w l e d g e of t h e p h y s i c a l w o r l d . C o m p a r e the f o l l o w i n g : 1 flip a c o i n , a s k i n g y o u to call ' H e a d s ' or ' T a i l s ' . I tell y o u that if y o u call ' H e a d s ' a n d g u e s s right I shall give y o u a p r i z e , w h e r e a s if you call ' T a i l s ' a n d g u e s s right y o u will g e t n o t h i n g . Plainly y o u w o u l d h a v e g o o d p r a g m a t i c r e a s o n to call ' H e a d s ' , s i n c e this is t h e o n l y s t r a t e g y that m i g h t gain y o u a r e w a r d . But y o u certainly w o u l d n o t know that the coin will c o m e u p H e a d s , e v e n if it d o e s in fact d o s o . T h i s is exactly a n a l o g o u s to t h e p r o p o s a l that w e a r e j u s t i f i e d , o n p r a g m a t i c g r o u n d s , in e m p l o y i n g i n d u c t i o n . T h e analytic p r o p o s a l to s o l v e t h e p r o b l e m of i n d u c t i o n c l a i m s that in o r d e r to justify i n d u c t i o n w e n e e d l o o k n o f u r t h e r t h a n o u r c o n c e p t of j u s t i f i c a t i o n itself. O n this v i e w , i n d u c t i o n f o r m s p a r t of o u r c o n c e p t i o n of w h a t j u s t i f i c a t i o n is, in s u c h a w a y that ' I n d u c t i o n is j u s t i f i e d ' is a n a n a l y t i c t r u t h . It is t h e r e f o r e a m i s t a k e to try to j u s t i f y i n d u c t i o n in t e r m s of a n y t h i n g e l s e , l e a s t of all in t e r m s of deduction. R a t h e r , i n d u c t i v e a r g u m e n t s f o r m a p r i m i t i v e (that is, basic) part o f o u r p r a c t i c e of j u s t i f y i n g a n d s e e k i n g j u s t i f i c a t i o n for b e l i e f s , fully o n a p a r w i t h d e d u c t i v e a r g u m e n t s . Plainly this p r o p o s a l a d m i t s of e x t e n s i o n to t h e w i d e r c a t e g o r y of i n f e r e n c e to t h e b e s t e x p l a n a t i o n , if a n y t h i n g b e c o m i n g s o m e w h a t m o r e p l a u s i b l e in t h e p r o c e s s . W e n e e d o n l y claim t h a t it is a n a l y t i c — a n e c e s s a r y c o m p o n e n t of o u r c o n c e p t of j u s t i f i c a t i o n — t h a t a n i n f e r e n c e to 2

2

T h i s v i e w is d e f e n d e d b y A r m s t r o n g , What is a Law of Nature?

c h . 4, s e c t . 5 .

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t h e b e s t available e x p l a n a t i o n of s o m e p h e n o m e n o n is a l w a y s justified. T h e m a i n t r o u b l e w i t h this r e s p o n s e to t h e p r o b l e m of i n d u c t i o n , h o w e v e r , is that it is surely p o s s i b l e for u s to q u e s t i o n t h e a p p r o p r i a t e n e s s o f a c c e p t e d s t a n d a r d s of j u s t i f i c a t i o n . W e can a l l o w that i n d u c t i v e practices f o r m part o f o u r c o n c e p t o f j u s t i f i c a t i o n , a n d h e n c e a l l o w that i n d u c t i v e l y g r o u n d e d b e l i e f s are j u s t i f i e d b y a c c e p t e d s t a n d a r d s , a n d y e t ask w h e t h e r t h o s e s t a n d a r d s a r e reliable g u i d e s to t h e t r u t h . T h e d e e p q u e s t i o n is w h e t h e r i n d u c t i v e l y g r o u n d e d b e l i e f s a r e likely to b e true, n o t w h e t h e r w e call s u c h beliefs ' j u s t i f i e d ' . In o r d e r to s e e t h i s , i m a g i n e a c o m m u n i t y that e m p l o y s a c o u n t e r - i n d u c t i o n rule. T h i s e n t i t l e s t h e m to d e r i v e , f r o m a p r e m i s s of t h e form 'AH o b s e r v e d A s h a v e b e e n B s ' , t h e c o n c l u s i o n 'All t h e r e m a i n i n g A s are not B ' . T h e y , t o o , m a y r e s p o n d to t h e d e m a n d that t h e y justify their p r a c t i c e by c l a i m i n g that t h e p r o p o s i t i o n ' C o u n t e r i n d u c t i o n is j u s t i f i e d ' is, for t h e m , a n a l y t i c . T h e y m a y c l a i m , w i t h j u s t a s m u c h w a r r a n t a s o u r s e l v e s , that t h e practice o f c o u n t e r - i n d u c t i o n f o r m s a n e c e s s a r y i n g r e d i e n t in their c o n c e p t of j u s t i f i c a t i o n . Y e t plainly their practice c a n n o t b e justified (in t h e s e n s e of ' t r u t h - c o n d u c i v e ' ) if o u r s is. Exactly similar p o i n t s m a y b e m a d e in c o n n e c t i o n w i t h t h e p r o p o s e d analytic justification of o u r practice of i n f e r r i n g to t h e b e s t e x p l a n a t i o n . T h e i n d u c t i v e p r o p o s a l to s o l v e t h e p r o b l e m o f i n d u c t i o n a r g u e s that, s i n c e i n d u c t i o n h a s b e e n r e m a r k a b l y s u c c e s s f u l in o b t a i n i n g t r u t h s for u s in t h e p a s t , it is, v e r y likely, a g e n e r a l l y reliable m o d e of i n f e r e n c e . T h i s a r g u m e n t is, of c o u r s e , itself i n d u c t i v e , t h u s i m m e d i a t e l y g i v i n g rise to a c h a r g e of circularity. B u t t h e p r o p o n e n t s of this p r o p o s a l m a y reply that t h e reliability o f i n d u c t i o n d o e s n o t actually f i g u r e a s a p r e m i s s of t h e a r g u m e n t . R a t h e r , i n d u c t i o n is h e r e u s e d a s a r u l e , o r p r i n c i p l e of i n f e r e n c e , in t h e c o u r s e o f a r g u i n g f o r t h e reliability of s u c h i n f e r e n c e . M o r e o v e r , w e c a n n o t i n s i s t that all p r i n c i p l e s of i n f e r e n c e s h o u l d b e t r a n s f o r m e d i n t o explicit p r e m i s s e s , o n p a i n of a v i c i o u s r e g r e s s . T h e n , s i n c e t h e o n l y p r e m i s s of t h e a b o v e a r g u m e n t is t h e p a s t s u c c e s s of i n d u c t i o n , t h e r e is n o f o r m a l 3

F o r e x a m p l e , if y o u r e f u s e t o a c c e p t t h e i n f e r e n c e f r o m ' P & Q ' t o ' P ' until y o u a r e g i v e n a s a n e x p l i c i t p r e m i s s 'if P & Q t h e n P ' , t h e n y o u o u g h t e q u a l l y t o r e f u s e t o a c c e p t this i n f e r e n c e u n t i l y o u a r e g i v e n a s a p r e m i s s 'if (if P & Q t h e n P ) and P & Q, then P', a n d so o n . 3

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circularity. In t h e s a m e w a y , w e m a y d e f e n d t h e w i d e r c a t e g o r y of i n f e r e n c e to t h e b e s t e x p l a n a t i o n b y a r g u i n g that t h e b e s t e x p l a n a t i o n of o u r p a s t s u c c e s s in t h e u s e of s u c h i n f e r e n c e is that it is g e n e r a l l y reliable as a m o d e of a r g u m e n t . H e r e , t o o , i n f e r e n c e to t h e b e s t e x p l a n a t i o n is used, r a t h e r t h a n t a k e n as a premiss. T h e situation m a y b e c o m p a r e d w i t h t h e u s e of s o u n d n e s s p r o o f s in d e d u c t i v e logic, w h e r e w e d e m o n s t r a t e ( d e d u c t i v e l y ) that o u r s y s t e m of r u l e s can o n l y g e n e r a t e t r u t h s f r o m t r u t h s . G e n e r a l l y s u c h p r o o f s will e m p l o y t h e v e r y s a m e p r i n c i p l e s of i n f e r e n c e that a r e in q u e s t i o n . For e x a m p l e , c o n s i d e r t h e rule of cfe-elimination, w h i c h a l l o w s u s to d e r i v e ' A ' (or a l t e r n a t i v e l y ' B ' ) from ' A & B ' . A p r o o f of the s o u n d n e s s of this rule m i g h t p r o c e e d as f o l l o w s . 1. 2. 3. 4. 5.

If ' A & 13' is t r u e , t h e n ' A ' is t r u e a n d ' B ' is true ( d e f i n i t i o n ) . S u p p o s e ' A & B ' is t r u e . T h e n ' A ' is t r u e a n d ' B ' is true ( f r o m 1 a n d 2 ) . T h e n ' A ' is t r u e (from 3 ) . S o if ' A & B ' is t r u e , t h e n ' A ' m u s t b e t r u e ( f r o m 2-4).

H e r e the & - e l i m i n a t i o n rule h a s itself b e e n used, in t h e s t e p f r o m line 3 to line 4 . S u c h p r o o f s a r e g e n e r a l l y said to b e explicative r a t h e r t h a n persuasive, in that t h e y c a n n o t c o n v i n c e s o m e o n e of t h e s o u n d n e s s o f & - e l i m i n a t i o n w h o r e f u s e s to e m p l o y it at all. R a t h e r , t h e y a m o u n t to a u s e of o u r p r i n c i p l e s of r e a s o n i n g to e x p l a i n to o u r s e l v e s h o w it is that s u c h p r i n c i p l e s c a n g u a r a n t e e truth f r o m truth. In t h e s a m e w a y , it m a y b e s a i d , w e c a n e x p l i c a t e t h e reliability of i n d u c t i o n , or o f i n f e r e n c e to t h e b e s t e x p l a n a t i o n , b y m e a n s of a n a r g u m e n t that e m p l o y s t h a t v e r y principle. T h e m a i n p r o b l e m for this p r o p o s a l a r i s e s o u t of o u r i m a g i n e d c o u n t e r - i n d u c t i v e c o m m u n i t y , m e n t i o n e d in c o n n e c t i o n w i t h t h e analytic p r o p o s a l a b o v e . F o r n o t i c e that w e c a n n o t h o p e to c o n v i n c e t h e m e m b e r s of this c o m m u n i t y of t h e e r r o r of their w a y s , b y p o i n t i n g to their e x t e n s i v e failures in t h e u s e of c o u n t e r - i n d u c t i o n in t h e p a s t . F o r t h e y will r e a s o n c o u n t e r inductively, from the premiss that counter-induction has mostly failed in t h e p a s t , t o t h e c o n c l u s i o n that m o s t f u t u r e c a s e s of c o u n t e r - i n d u c t i o n will s u c c e e d . S i m i l a r l y , if w e i m a g i n e a c o m m u n i t y of p e o p l e w h o h a v e t h e p r a c t i c e of r e a s o n i n g to t h e worst e x p l a n a t i o n of a g i v e n p h e n o m e n o n ( e i t h e r explicitly, o r

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by i n v e r t i n g all o u r c a n o n s o f b e s t e x p l a n a t i o n — f o r e x a m p l e , p r e f e r r i n g t h e m o r e c o m p l e x of t w o e x p l a n a t i o n s , o t h e r t h i n g s b e i n g e q u a l ) , t h e n t h e y will r e s p o n d to p a s t failures b y c o n c l u d i n g t h a t c o u n t e r - e x p l a n a t i o n is v e r y p r o b a b l y reliable. F o r t h e h y p o t h e s i s of g e n e r a l reliability p r o v i d e s t h e w o r s t available e x p l a n a t i o n o f their lack o f s u c c e s s in t h e p a s t . T h e p o i n t is that w e d o s e e m to n e e d more t h a n a m e r e l y e x p l i c a t i v e a r g u m e n t in s u p p o r t of i n d u c t i o n or i n f e r e n c e to t h e b e s t explanation. For otherwise what reason do I have, b e y o n d mere l a z i n e s s , for n o t s w i t c h i n g o v e r to t h e c o u n t e r - i n d u c t i v e or counter-explanatory practice? W h a t e m e r g e s is that a t t e m p t s to justify e i t h e r i n d u c t i o n or i n f e r e n c e to t h e b e s t e x p l a n a t i o n h a v e n o t m e t with a n y g r e a t d e g r e e of s u c c e s s . I shall n o w c o n s i d e r w h e t h e r w e m i g h t fare a n y b e t t e r if w e w e r e g i v e n , a s a p r e m i s s , t h e i n n a t e n e s s of o u r c o n c e p t o f b e s t e x p l a n a t i o n . I shall h e n c e f o r w a r d a d d r e s s m y s e l f to this w i d e r c a t e g o r y of n o n - d e d u c t i v e a r g u m e n t , l e a v i n g i n d u c t i o n to b e t a k e n c a r e of implicitly a s a result.

The A r g u m e n t s R e v a m p e d O n e distinctive f e a t u r e of t h e n a t i v i s m d e f e n d e d in c h a p t e r 7 is that it p l a c e s o u r u s e of i n f e r e n c e to t h e b e s t e x p l a n a t i o n firmly w i t h i n t h e faculty o f r e a s o n . F o r w e d o s e e m to p o s s e s s a c o n s c i o u s c o n c e p t of b e s t e x p l a n a t i o n , w h i c h s e r v e s to g u i d e o u r e v a l u a t i o n s of c o m p e t i n g e x p l a n a t i o n s in particular c a s e s . (This c o n t r a s t s w i t h t h e v i e w of H u m e , w h o t h o u g h t that i n d u c t i o n r e s u l t e d f r o m i n n a t e l y g i v e n a s p e c t s of o u r faculty of i m a g i n a t i o n . ) W h a t this t h e n m e a n s is that i n f e r e n c e to t h e b e s t e x p l a n a t i o n d o e s n o t m e r e l y h a p p e n to b e l o n g w i t h i n o u r c o n c e p t i o n of j u s t i f i c a t i o n , as t h e a n a l y t i c p r o p o s a l m a i n t a i n s . R a t h e r , it is a n i n n a t e l y d e t e r m i n e d c o n s t i t u t i v e p a r t of t h e h u m a n r e a s o n i n g faculty itself. It t h e r e f o r e f o l l o w s that o u r i m a g i n e d c o u n t e r - e x p l a n a t o r y c o m m u n i t y is i m p o s s i b l e f o r u s . For while innateness does not immediately imply inevitability— for e x a m p l e , s e x u a l d e s i r e is i n n a t e , b u t s o m e m a y s u c c e s s f u l l y train t h e m s e l v e s n o t to feel i t — i n f e r r i n g to t h e b e s t e x p l a n a t i o n is s u r e l y too b a s i c a p r i n c i p l e of o u r c o g n i t i o n t o b e a l t e r a b l e b y conscious choice or training. I n d e e d , m a n y of H u m e ' s reasons

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for t h e p s y c h o l o g i c a l inevitability of i n d u c t i v e r e a s o n i n g carry o v e r to t h e c a s e of i n f e r e n c e to t h e b e s t e x p l a n a t i o n , n o w c o n s t r u e d as p a r t of o u r faculty of r e a s o n . W e still face t h e m a i n o b j e c t i o n raised a g a i n s t t h e a n a l y t i c p r o p o s a l , h o w e v e r , n a m e l y that it c a n n o t settle t h e q u e s t i o n of the c o n n e c t i o n b e t w e e n a c c e p t e d s t a n d a r d s of justification a n d truth. For t h i s , w e n e e d to c o n s i d e r t h e w i d e r a n a l o g u e of t h e i n d u c t i v e p r o p o s a l ( c o n c e r n i n g t h e justification of i n f e r e n c e to t h e b e s t e x p l a n a t i o n ) . H e r e , t o o , t h e c l a i m e d i n n a t e n e s s of o u r c o n c e p t of b e s t e x p l a n a t i o n m a y b e of real h e l p . F o r if t h e p r i n c i p l e of i n f e r r i n g to the b e s t e x p l a n a t i o n f o r m s a c o n s t i t u t i v e p a r t of o u r c o g n i t i v e a p p a r a t u s , t h e n of c o u r s e w e c a n n o t b u t rely u p o n it in f o r m i n g o u r b e l i e f s , w h e t h e r at t h e first-order l e v e l , or w h e n w e c o m e to d o e p i s t e m o l o g y . If i n f e r r i n g to t h e b e s t e x p l a n a t i o n is p a r t of w h a t r e a s o n i n g ;'s, for u s , t h e n the fact that it c a n o n l y b e s u p p o r t e d by itself n e e d give n o particular c a u s e for c o n c e r n , o r for s c e p t i c i s m . J u s t a s o u r b e s t u s e of d e d u c t i v e r e a s o n s u p p o r t s its o w n s o u n d n e s s , s o too o u r b e s t u s e o f n o n - d e d u c t i v e r e a s o n s u p p o r t s its o w n g e n e r a l reliability. F o r t h e b e s t e x p l a n a t i o n of o u r s u c c e s s in r e a s o n i n g to t h e b e s t e x p l a n a t i o n in the p a s t is that s u c h i n f e r e n c e is g e n e r a l l y r e l i a b l e . ( T o s e e t h e e x t e n t of o u r p a s t s u c c e s s , reflect again on t h e w a y in w h i c h i n f e r e n c e to t h e b e s t e x p l a n a t i o n is i m p l i c a t e d in a l m o s t e v e r y a s p e c t of o u r practical lives, a s well as on its u s e in s c i e n c e . ) M o r e o v e r , w e c a n n o t n o w o b j e c t that c o u n t e r e x p l a n a t o r y c o m m u n i t i e s c o u l d e q u a l l y well u s e i n f e r e n c e to t h e w o r s t e x p l a n a t i o n t o s u p p o r t t h e g e n e r a l reliability of their practice. For since such communities are not genuinely possible for u s , t h e m e r e fact that t h e y a r e i m a g i n a b l e n e e d n o t u n d e r m i n e t h e j u s t i f i c a t i o n of o u r o w n p r o c e d u r e . A t t h e very least, all s e n s e o f a r b i t r a r i n e s s in t h e t h o u g h t that I h a v e n o t s w i t c h e d o v e r to a c o u n t e r - e x p l a n a t o r y p r a c t i c e is r e m o v e d . 4

It a p p e a r s that a n e m p i r i c i s t w h o c a n b e b r o u g h t to e n d o r s e a n a p p r o p r i a t e f o r m of n a t i v i s m , c o n c e r n i n g o u r c o n c e p t of b e s t explanation, may m a k e considerable headway with the problem of j u s t i f y i n g n o n - d e d u c t i v e m o d e s of i n f e r e n c e . In p a r t i c u l a r , s u c h a n e m p i r i c i s t m a y a d v a n c e v e r s i o n s of t h e a n a l y t i c a n d i n d u c t i v e p r o p o s a l s t h a t are m u c h s t r o n g e r t h a n t h e i r o r d i n a r y — n o n - n a t i v i s t i c — c o u n t e r p a r t s . I n f e r e n c e to t h e b e s t e x p l a n a 4

T h e d e m o n s t r a t i o n t h a t this is s o I shall l e a v e a s a n e x e r c i s e f o r t h e r e a d e r .


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tion c a n in c o n s e q u e n c e b e s e e n to f o r m a c o n s t i t u t i v e part of h u m a n r e a s o n , a n d t h e n t h e b e s t u s e of that r e a s o n l e a d s to t h e c o n c l u s i o n that it is itself g e n e r a l l y reliable. H o w e v e r , t h e i n n a t e n e s s h y p o t h e s i s also g i v e s rise to a n a r g u m e n t for t h e reliability of i n f e r e n c e to t h e b e s t e x p l a n a t i o n that is largely i n d e p e n d e n t of t h e s e , a s I shall n o w e x p l a i n . 5

A N e w A r g u m e n t from Nativism M y claim is that t h e o n l y plausible e v o l u t i o n a r y e x p l a n a t i o n , o f w h y i n f e r e n c e to the b e s t e x p l a n a t i o n s h o u l d b e an i n n a t e l y d e t e r m i n e d a s p e c t of h u m a n r e a s o n , is that it is g e n e r a l l y reliable. T o this it m i g h t possibly b e o b j e c t e d that a n i n n a t e c o n c e p t of b e s t e x p l a n a t i o n , w h i l e h a v i n g no survival value in itself, c o u l d b e a b y - p r o d u c t of s o m e t h i n g that d o e s h a v e v a l u e for s u r v i v a l . But this s u g g e s t i o n is too n e b u l o u s to take s e r i o u s l y . Until s o m e specific proposal is put f o r w a r d , c o n c e r n i n g w h a t this o t h e r i n n a t e p r o p e r t y m i g h t b e , it will b e m o r e r e a s o n a b l e to b e l i e v e that o u r c o n c e p t of b e s t e x p l a n a t i o n h a s survival v a l u e in its o w n right. A real attack c a n b e m o u n t e d , h o w e v e r , on the s u p p o s e d reliability of at least o n e of t h e s t r a n d s in o u r c o n c e p t of b e s t e x p l a n a t i o n , n a m e l y that of s i m p l i c i t y . For it a p p e a r s e a s y to e x p l a i n h o w a faculty of r e a s o n that c h o o s e s b e t w e e n t h e o r i e s o n g r o u n d s of simplicity ( o t h e r t h i n g s b e i n g e q u a l ) c o u l d h a v e a v a l u e in survival that is u n r e l a t e d to truth. For t h e o r i e s that a r e s i m p l e r will b e e a s i e r to o p e r a t e w i t h a n d think in t e r m s of, h e n c e m a k i n g c o g n i t i v e p r o c e s s i n g m o r e efficient. I h a v e a n u m b e r of p o i n t s to m a k e in r e s p o n s e to this s u g g e s t i o n . T h e first is that, e v e n if o n e s t r a n d in t h e c o n c e p t o f b e s t e x p l a n a t i o n b e a r s n o relation to t r u t h , this d o e s n o t b e g i n to u n d e r m i n e t h e reliability of i n f e r e n c e to t h e b e s t e x p l a n a t i o n as a w h o l e . I n d e e d ( a n d t h i s b r i n g s m e to m y s e c o n d p o i n t ) , it is h a r d to s e e w h a t t h e v a l u e o f efficient c o g n i t i v e p r o c e s s i n g c o u l d b e , u n l e s s it is that w e are m o r e likely to b e s u c c e s s f u l in d e r i v i n g truths f r o m s i m p l e t h e o r i e s t h a n f r o m c o m p l e x o n e s . B u t t h e n this v a l u e will A p r e c u r s o r o f this a r g u m e n t m a y b e f o u n d in K o n r a d L o r e n z , Behind the Mirror ( L o n d o n : M e t h u e n , 1 9 7 7 ) . S e e a l s o t h e p a p e r s c o l l e c t e d in G. R a d n i t z k y a n d W . B a r t l e y ( e d s . ) , Evolutionary Epistemology ( L a S a l l e , 111.: O p e n C o u r t , 1 9 8 7 ) . 5

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o n l y m a n i f e s t itself, in g e n e r a l , w h e n t h e t h e o r y in q u e s t i o n is itself t r u e , or at least close to t h e t r u t h . W h i l e it c a n i n d e e d h a p p e n that t r u e c o n c l u s i o n s a r e d e r i v e d f r o m w h o l l y false p r e m i s s e s , this will o n l y o c c u r by a c c i d e n t . But the p o i n t I m o s t w a n t to insist on is t h i s . W h i l e it is i n d e e d t h e c a s e that o n e s t r a n d in o u r n o t i o n of simplicity is a m a t t e r of n o t a t i o n a l e l e g a n c e , or e c o n o m y of e x p r e s s i o n , t h e r e is a n o t h e r s t r a n d in t h e n o t i o n that is a r g u a b l y m o r e i m p o r t a n t , a n d that is b e s t s u b s u m e d w i t h i n t h e n o t i o n of e x p l a n a t o r y p o w e r . T h i s is the sort of structural simplicity that is at i s s u e w h e n w e are told n o t to p o s t u l a t e entities b e y o n d w h a t is n e c e s s a r y , a n d to p r e f e r e x p l a n a t i o n s that e m p l o y t h e f e w e s t n u m b e r of e x p l a n a t o r y factors. For e x a m p l e , if my h o u s e h a s b e e n b u r g l e d t h e n 1 s h o u l d c o n c l u d e , o t h e r t h i n g s b e i n g equal (that is, in t h e a b s e n c e of t w o or m o r e sets of f o o t p r i n t s or f i n g e r p r i n t s , or of e v i d e n c e that b u r g l a r s m o s t often w o r k in pairs), that t h e c r i m e w a s the w o r k of a s i n g l e i n d i v i d u a l . F o r the h y p o t h e s i s of a s i n g l e b u r g l a r is s i m p l e r than the h y p o t h e s i s of t w o , or t h r e e , or f o u r . But the virtue of this sort of simplicity is n o t a m a t t e r of e a s e of e x p r e s s i o n . It is, r a t h e r , that the s i m p l e r t h e o r y at t h e s a m e t i m e e x p l a i n s t h e absence of a n y e v i d e n c e of m o r e than o n e b u r g l a r , t h u s h a v i n g g r e a t e r e x p l a n a t o r y p o w e r t h a n its rivals. A n d it is hard to s e e h o w the survival value of e x p l a n a t o r y p o w e r can similarly b e e x p l a i n e d a w a y in t e r m s u n r e l a t e d to truth. It c a n f u r t h e r b e o b j e c t e d that w h i l e e v o l u t i o n m i g h t h a v e b e e n reliable in s e l e c t i n g a c o n c e p t of b e s t e x p l a n a t i o n that w o u l d g e n e r a t e t r u t h s c o n c e r n i n g m a t t e r s of i m m e d i a t e sign i f i c a n c e for t h e survival of p r i m i t i v e p e o p l e , this g i v e s u s n o r e a s o n to t h i n k that it will b e generally reliable, particularly w i t h r e g a r d to t h e o r e t i c a l s c i e n c e . O n e r e s p o n s e is to d e n y that t h e r e is a n y p r i n c i p l e d d i s t i n c t i o n b e t w e e n c o m m o n - s e n s e a n d scie n c e . S u p p o s e , for e x a m p l e , that it is said to b e distinctive of scientific t h e o r i e s that t h e y deal w i t h u n o b s e r v a b l e e n t i t i e s , s u c h as e l e c t r o n s . It m a y t h e n b e p r o p o s e d that e v o l u t i o n g i v e s u s n o r e a s o n to trust i n f e r e n c e to t h e b e s t e x p l a n a t i o n in c o n n e c t i o n w i t h u n o b s e r v a b l e s . B u t w e o n l y h a v e to reflect to s e e that this will n o t d o . F o r t h e p a s t is j u s t a s u n o b s e r v a b l e as a n e l e c t r o n . Y e t b e i n g able to r e a s o n t h a t t h e b e s t e x p l a n a t i o n of f r e s h p a w - m a r k s in t h e m u d is that a tiger h a s b e e n h e r e v e r y r e c e n t l y m a y b e crucial in e n s u r i n g o u r survival.

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A n o t h e r p o i n t is that o u r c o n c e p t of b e s t e x p l a n a t i o n h a d t o b e fit to s e r v e u s in a l m o s t a n y e n v i r o n m e n t , f r o m t h e e q u a t o r to the p o l e s . F o r of c o u r s e t h e distinctive fact a b o u t h u m a n b e i n g s a s a s p e c i e s , a s w e n o t e d in d i s c u s s i n g t h e i n n a t e n e s s of folkp s y c h o l o g y in c h a p t e r 8, is that w e a r e u n i q u e l y a d a p t a b l e , h a v i n g a d i s t r i b u t i o n o v e r t h e g l o b e that n o o t h e r s p e c i e s h a s . It is h a r d to s e e h o w a n y c o n c e p t c o u l d s u b s e r v e this p u r p o s e e x c e p t o n e that w o u l d b e g e n e r a l l y reliable. F o r c o n c e p t s that a r e reliable o n l y in c o n n e c t i o n with p h e n o m e n a on F a r t h , for e x a m p l e , can be ruled out on the g r o u n d s that they m i g h t lead o n e to predict that t h e s u n will not return next d a y , a n d h e n c e to fail to m a k e crucial p r o v i s i o n for the m o r r o w . O f c o u r s e it m u s t b e p o s s i b l e , in principle, to c o b b l e t o g e t h e r s o m e sort of artificial c o n c e p t that w o u l d e m b r a c e o n l y t h o s e a s p e c t s of n a t u r e with s i g n i f i c a n c e for p r o - t e c h n o l o g i c a l survival. A n d it m i g h t t h e n b e s u g g e s t e d that e v o l u t i o n could h a v e s e l e c t e d a c o n c e p t of best e x p l a n a t i o n that w o u l d bo reliable in t h o s e c i r c u m s t a n c e s o n l y . But to this w e can m a k e t w o s e p a r a t e r e p l i e s . T h e first a p p e a l s to y e t a n o t h e r form of i n n a t e n e s s , n a m e l y o u r i n n a t e ability to d e t e c t g e n u i n e r e s e m b l a n c e s b e t w e e n t h i n g s . It is plain that w e d o h a v e s u c h an ability, a n d that it h a s survival v a l u e in its o w n r i g h t . In w h i c h c a s e it is u n l i k e l y that p r e - t e c h n o l o g i c a l a n d scientific p h e n o m e n a s h o u l d strike u s as s o similar (in all t h o s e r e s p e c t s that m a t t e r for e x p l a n a t i o n a n d p r e d i c t i o n ) , w h e n really they are n o t . The s e c o n d reply is that w e h a v e e v e r y r e a s o n to think that e v o l u t i o n h a s d e l i v e r e d u s a c o n c e p t o f b e s t e x p l a n a t i o n w h o s e reliability is not limited in t h e m a n n e r s u g g e s t e d . F o r the b e s t e x p l a n a t i o n , b o t h of o u r s u c c e s s in m a k i n g s e n s e of t h e w o r l d in t h e p a s t , a n d of o u r c o n t i n u i n g scientific s u c c e s s , is that o u r e x t e n d e d u s e of i n f e r e n c e to t h e b e s t e x p l a n a t i o n c o n t i n u e s to be reliable. ( H e r e t h e a r g u m e n t m e r g e s with t h e a n a l o g u e of t h e i n d u c t i v e proposal, outlined above.) h

W e c a n reply in t h e s a m e sort of w a y t o a r a t h e r d i f f e r e n t o b j e c t i o n . T h i s w o u l d b e that t h e survival v a l u e , a n d h e n c e reliability, of o u r c o n c e p t of b e s t e x p l a n a t i o n in t h e p a s t p r o v i d e s n o g u a r a n t e e o f c o n t i n u e d survival v a l u e , o r reliability, in t h e f u t u r e . F o r in fact t h e b e s t e x p l a n a t i o n for t h e o b s e r v e d regularity of n a t u r e in t h e p a s t is that n a t u r e is g o v e r n e d b y l a w s t h a t o p e r a t e i n d e p e n d e n t l y of t i m e a n d p l a c e . M o r e o v e r , t h e 6

O n this s e e Q u i n e ' N a t u r a l K i n d s ' , in Ontological

Relativity.

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b e s t e x p l a n a t i o n of o u r s u c c e s s in m a k i n g s e n s e of t h e w o r l d in t h e p a s t is t h a t w e h a v e an i n n a t e ability to d e t e c t t h o s e p r o p e r t i e s that figure in p r o j e c t a b l e l a w s . S o w e h a v e r e a s o n to t h i n k that t h o s e p r o p e r t i e s of t h e w o r l d that c o n f e r r e d survival v a l u e on o u r u s e of i n f e r e n c e to the b e s t e x p l a n a t i o n in t h e p a s t will c o n t i n u e to d o s o . ( W h i l e t h e r e is an o b v i o u s circularity in this r e p l y , it is in fact not v i c i o u s , b u t a v i r t u o u s c o h e r e n c e , for r e a s o n s that will e m e r g e in the n e x t s e c t i o n . ) A final o b j e c t i o n to the a r g u m e n t from t h e i n n a t e n e s s of o u r c o n c e p t of b e s t e x p l a n a t i o n to the c o n c l u s i o n of reliability is that s u c h a c o n c e p t only e n a b l e s us to m a k e a c h o i c e from a m o n g s t t h e v a r i o u s t h e o r i e s that h a v e actually b e e n p r o p o s e d . S o to s a y that it is reliable is just to say t h a t , of the t h e o r i e s s u g g e s t e d , it t e n d s to select t h e o n e that is m o s t likely to b e t r u e . But t h e n t h e u s e of s u c h a c o n c e p t will o n l y g e n e r a l l y lead to the truth if t h e correct t h e o r y is a m o n g s t t h o s e a n t e c e d e n t l y g i v e n . S o e v e n if t h e concept of b e s t e x p l a n a t i o n is g e n e r a l l y reliable, this g i v e s u s n o r e a s o n to t h i n k that inference to the b e s t e x p l a n a t i o n is g e n e r a l l y reliable. But the reply to this is e a s y . It is that w e surely h a v e to s u p p o s e that o u r faculty for g e n e r a t i n g h y p o t h e s e s w o u l d e v o l v e a l o n g s i d e o u r c o n c e p t of b e s t e x p l a n a t i o n . F o r w h a t w o u l d b e the survival v a l u e of h a v i n g a c o n c e p t of b e s t e x p l a n a t i o n that is reliable in the a b o v e s e n s e , if w e did n o t a l s o t e n d to g e n e r a t e r a n g e s of h y p o t h e s e s that i n c l u d e t h e correct one? I c o n c l u d e that it is v e r y h a r d i n d e e d to s e e w h a t p o s s i b l e a d v a n t a g e p o s s e s s i o n of a c o n c e p t of b e s t e x p l a n a t i o n c o u l d c o n f e r in s u r v i v a l , u n l e s s s u c h a c o n c e p t w e r e g e n e r a l l y reliable in o b t a i n i n g for u s t r u t h s , a r o u n d w h i c h w e c o u l d t h e n c o n s t r u c t o u r p l a n s a n d p r o j e c t s . In w h i c h c a s e , n o t o n l y d o e s t h e i n n a t e n e s s of i n f e r e n c e to t h e b e s t e x p l a n a t i o n m e a n that s u c h i n f e r e n c e f o r m s a c o n s t i t u t i v e part of a n y p o s s i b l e h u m a n c o n c e p t of j u s t i f i c a t i o n , b u t it also g i v e s u s t w o r e a s o n s for t h i n k i n g that t h e r e is a c o n n e c t i o n b e t w e e n o u r s t a n d a r d s of j u s t i f i c a t i o n a n d t r u t h . ( T h e s e r e a s o n s a r e , n a m e l y , that t h e b e s t e x p l a n a t i o n of o u r p a s t s u c c e s s in t h e u s e of b e s t e x p l a n a t i o n is g e n e r a l reliability, a n d that g e n e r a l reliability p r o v i d e s t h e b e s t e x p l a n a t i o n of t h e i n n a t e n e s s of o u r c o n c e p t of b e s t e x p l a n a t i o n . ) T h e r e r e m a i n s , h o w e v e r , t h e c h a r g e of circularity o u t l i n e d at t h e o u t s e t of o u r d i s c u s s i o n . F o r t h e a r g u m e n t for n a t i v i s m is

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itself a n i n f e r e n c e to t h e b e s t e x p l a n a t i o n . I n d e e d , it is o n e that p r e s u p p o s e s that w e h a v e k n o w l e d g e of a w o r l d o f p h y s i c a l o b j e c t s , s i n c e w e c o u l d o t h e r w i s e h a r d l y b e e n t i t l e d to a p p e a l to e v o l u t i o n a r y t h e o r y . I shall n o w t u r n to t h e task of r e b u t t i n g — o r at least d e f u s i n g — t h i s c h a r g e .

A Modest Coherentism U n d o u b t e d l y t h e m o s t i m p o r t a n t role for t h e c l a i m e d i n n a t e n e s s o f o u r c o n c e p t of b e s t e x p l a n a t i o n is that it f o r c e s o n u s at least a m o d e s t f o r m of c o h e r e n t i s m . For recall from c h a p t e r 7 that w h a t m a y m a k e o n e e x p l a n a t i o n b e t t e r t h a n a n o t h e r is, in part, its g r e a t e r internal c o n s i s t e n c y a n d its h i g h e r d e g r e e of c o h e r e n c e with o t h e r r e c e i v e d beliefs a n d t h e o r i e s . In a c c e p t i n g that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is a n i n n a t e l y d e t e r m i n e d c o n s t i t u t i v e a s p e c t of h u m a n r e a s o n , w e a r e t h e r e f o r e a c c e p t i n g that the justification for o u r beliefs m u s t c o n s i s t partly in their overall c o h e r e n c e . T h i s m a y t h e n e n a b l e u s g e n u i n e l y to ' b o o t s t r a p ' o u r w a y , n o t o n l y to a justified belief in t h e reliability of i n f e r e n c e to t h e b e s t e x p l a n a t i o n , b u t also to a justified belief in t h e physical w o r l d a s the b e s t a v a i l a b l e e x p l a n a t i o n of o u r experience. It is true that t h e r e is a kind of circle i n v o l v e d in u s i n g i n f e r e n c e to t h e b e s t e x p l a n a t i o n to a r g u e for t h e i n n a t e n e s s of o u r c o n c e p t of b e s t e x p l a n a t i o n , w h i c h is t h e n u s e d in turn in a r g u i n g that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is g e n e r a l l y reliable. B u t this circularity is n o t a v i c i o u s o n e . R a t h e r , it is j u s t w h a t o n e w o u l d e x p e c t , g i v e n that the relation o f justification c o n s i s t s , in p a r t , in c o h e r e n c e w i t h i n a n d b e t w e e n n e i g h b o u r i n g t h e o r i e s . T h e b e s t u s e of o u r r e a s o n l e a d s u s to b e l i e v e that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is a c o n s t i t u t i v e p a r t of o u r r e a s o n , a n d h e n c e that a n a s p e c t o f w h a t a j u s t i f i c a t i o n f o r a b e l i e f m u s t c o n s i s t in, for u s , is a m a t t e r of c o h e r e n c e . T h e b e s t u s e of o u r r e a s o n t h e n l e a d s u s to b e l i e v e that o u r r e a s o n itself is g e n e r a l l y reliable, a n d that t h e b e s t e x p l a n a t i o n o f o u r p e r c e p t u a l b e l i e f s is t h a t p e r c e p t i o n is a g e n e r a l l y reliable g u i d e to t h e s t a t e s of t h e p h y s i c a l w o r l d . T h e s e b e l i e f s a n d e x p l a n a t i o n s i n t e r l o c k in a h i g h l y s a t i s f a c t o r y w a y , e n a b l i n g u s t o s a y

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that t h e y a r e a m p l y j u s t i f i e d — i n d e e d , t h a t t h e y c o n s t i t u t e genuine knowledge. W h i l e w e h a v e a c c e p t e d a c o h e r e n t i s t c o n c e p t i o n of justification, this is still a relatively w e a k f o r m of c o h e r e n t i s m . ( A l t e r n a t i v e l y , it m a y b e c o n s i d e r e d a w e a k e n e d f o r m of f o u n d a t i o n a l i s m . ) For w e d o n o t h a v e to a l l o w that all c o h e r e n t n e t w o r k s of true belief c o n s t i t u t e k n o w l e d g e , e v e n p r o v i d e d that t h e r e exists n o o t h e r equally c o h e r e n t n e t w o r k c o n c e r n i n g t h e s a m e s u b j e c t - m a t t e r . R a t h e r , w e c a n insist that e x p l a n a t o r y t h e o r i e s n e e d to b e tied d o w n in p e r c e p t i o n in o r d e r to c o u n t as j u s t i f i e d . S o t h e e x a m p l e g i v e n in c h a p t e r 5 , o f a c o h e r e n t n e t w o r k of beliefs a b o u t a c h a r a c t e r w h o is in fact fictional, will n o t c o u n t a s j u s t i f i e d on this v i e w . W h a t is g i v e n to u s — w h a t m u s t f o r m , a s it w e r e , t h e f o u n d a t i o n of o u r c o h e r e n t s y s t e m of belief, if it is to b e j u s t i f i e d — i s that t h e r e seems to u s to b e a w o r l d of p h y s i c a l o b j e c t s in t h r e e - d i m e n s i o n a l s p a c e . T h e s e s e e m i n g s o f t h e w o r l d c o n s t i t u t e t h e data for w h i c h o u r e x p l a n a t o r y t h e o r i e s a r e c o n s t r a i n e d to a c c o u n t . It is n o t j u s t in a c c e p t i n g a c o h e r e n t i s t c o n c e p t i o n of justification that e m p i r i c i s t s s h o u l d n o w m o v e a w a y f r o m classic f o u n d a t i o n a l i s m . T h e y s h o u l d also allow a n e l e m e n t of c o h e r e n c e to infect t h o s e v e r y s e e m i n g s of p h y s i c a l reality t h a t c o n s t i t u t e t h e f o u n d a t i o n for t h e e p i s t e m o l o g i c a l e n t e r p r i s e (that is, to k n o w w h a t w e k n o w ) . F o r w h e n it is p o i n t e d out that e v e n s u c h s e e m i n g s p r e s u p p o s e a g r a s p of their c o n s t i t u t i v e c o n c e p t s (that it s e e m s to y o u that y o u a r e sitting o n a c h a i r p r e s u p p o s e s that y o u h a v e a g r a s p of t h e c o n c e p t chair), a n e m p i r i c i s t n e e d n o l o n g e r reply (as I did in t h e last c h a p t e r ) that g r a s p of t h e c o n s t i t u t i v e c o n c e p t s m u s t b e p r e s u p p o s e d in a n y e n q u i r y . R a t h e r , w e c a n a l l o w that sceptical d o u b t s a b o u t o u r o w n c o n c e p t u a l abilities a r e p o s s i b l e , b u t r e p l y t h a t t h e b e s t available e x p l a n a t i o n for t h e fact that I s e e m able to m a k e r e g u l a r j u d g e m e n t s a n d classifications c o n c e r n i n g w h a t s e e m s to m e to b e a largely r e g u l a r w o r l d is that I d o i n d e e d p o s s e s s the ability to classify t h i n g s in a r e g u l a r m a n n e r . S o a l t h o u g h m y s e e m i n g s of p h y s i c a l reality c o n s t i t u t e a f o u n d a t i o n in t h e t h e o r y o f k n o w l e d g e , in s o far as t h e y a r e t h e b a s i c d a t a that n e e d to b e e x p l a i n e d , w e d o n o t h a v e to claim t h a t t h e y a r e 7

S e e m y Introducing detail. 7

Persons,

c h . 6 , w h e r e this s o r t o f i d e a is d e v e l o p e d in m o r e

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a b s o l u t e l y c e r t a i n , or t h a t t h e y a r e w h o l l y i n d e p e n d e n t of a n y other beliefs. W e c a n r e p l y in a similar m a n n e r to t h e sceptical s u g g e s t i o n that t h e d e m o n m a y b e m a k i n g m e g o w r o n g in m y u s e o f i n f e r e n c e to t h e b e s t e x p l a n a t i o n , l e a d i n g m e m i s t a k e n l y to p r e f e r t h e realist h y p o t h e s i s o v e r t h e h y p o t h e s i s of t h e d e m o n . F o r in fact t h e b e s t e x p l a n a t i o n of t h e intelligibility a n d c o h e r e n c e of m y c u r r e n t a p p r a i s a l s of i n f e r e n c e s to t h e b e s t e x p l a n a t i o n is that s u c h a p p r a i s a l s a r e g e n e r a l l y c o r r e c t . A n d a g a i n t h e a p p a r e n t circularity h e r e is n o t v i c i o u s , b u t is r a t h e r o n e of v i r t u o u s c o h e r e n c e . I n d e e d , it m a y b e w o r t h n o t i n g that t h e p r e s e n t line of d e f e n c e of r e a l i s m a b o u t k n o w l e d g e m a y also e x t e n d to r e a l i s m a b o u t truth, w h i c h w e d i s c u s s e d briefly in c h a p t e r 1, a n d h a v e s i n c e b e e n t a k i n g for g r a n t e d . F o r t h e b e s t t h e o r y of m y abilities to i d e n t i f y a n d classify t h i n g s (that i s , of t h e abilities t h a t u n d e r p i n t h e r e p r e s e n t a t i v e p o w e r s of m y t h o u g h t ) is that t h e y are r e a l i z e d in categorical b a s e s in t h e b r a i n , w h i c h o p e r a t e in a c c o r d a n c e w i t h l a w s of n a t u r e that a r e i n d e p e n d e n t of s p a c e and time. S o there are determinate truths about h o w those c a p a c i t i e s w o u l d r e s p o n d in r e m o t e r e g i o n s of s p a c e a n d t i m e that are in fact i n a c c e s s i b l e to m e , w h i c h s e e m s t o b e e n o u g h f o r m y p r e s e n t t h o u g h t s a b o u t t h o s e p l a c e s a n d t i m e s to b e d e t e r m i n a t e l y true or false. O r s o , at a n y r a t e , I b e l i e v e . 8

I c o n c l u d e t h a t w e are s u f f i c i e n t l y j u s t i f i e d in b e l i e v i n g i n f e r e n c e to t h e b e s t e x p l a n a t i o n to b e a g e n e r a l l y reliable m e t h o d of f o r m i n g b e l i e f s . T h i s is s o b e c a u s e t h e b e s t e x p l a n a tion of o u r p o s s e s s i o n of a c o n c e p t of b e s t e x p l a n a t i o n is t h a t t h e c o n c e p t is i n n a t e , a n d b e c a u s e t h e b e s t e x p l a n a t i o n of its i n n a t e n e s s is that it is generally reliable. It is also b e c a u s e the b e s t e x p l a n a t i o n of o u r p a s t s u c c e s s in t h e u s e of i n f e r e n c e to t h e b e s t explanation is that it is generally reliable, a n d b e c a u s e the b e s t e x p l a n a t i o n of p a s t regularities in n a t u r e is that n a t u r e is l a w - g o v e r n e d in s u c h a w a y t h a t p a s t regularities will c o n t i n u e . A n d it is b e c a u s e t h e i n n a t e n e s s of i n f e r e n c e to t h e b e s t e x p l a n a t i o n f o r c e s u s to s e e t h a t a j u s t i f i c a t i o n for a b e l i e f m a y c o n s i s t in t h e fact t h a t it h a n g s t o g e t h e r w i t h o t h e r b e l i e f s in j u s t this sort of i n t e r l o c k i n g w a y . W e m a y t h e r e f o r e c o n c l u d e t h a t 8

F o r f u r t h e r d e v e l o p m e n t o f t h i s i d e a , s e e m y Metaphysics

ch. 15.

of the

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190

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w e d o i n d e e d k n o w that w e h a v e k n o w l e d g e of t h e p h y s i c a l w o r l d , s i n c e t h e h y p o t h e s i s of reliable p e r c e p t i o n p r o v i d e s easily t h e b e s t a v a i l a b l e e x p l a n a t i o n of o u r p e r c e p t u a l b e l i e f s .

A n A r g u m e n t for O p e n M i n d s It is i m p o r t a n t to b e clear a b o u t j u s t w h a t t h e a r g u m e n t a b o v e h a s s h o w n — i n particular, that it p r o v i d e s u s w i t h n o b a s i s for c l a i m i n g to h a v e d e f e a t e d s o m e o n e w h o is a l r e a d y a c o n v i n c e d s c e p t i c . For e v e n if i n f e r e n c e to t h e b e s t e x p l a n a t i o n is u n a v o i d a b l e by v i r t u e of its i n n a t e n e s s , this d o e s n o t m e a n that w e n e c e s s a r i l y h a v e to b e l i e v e that t h e c o n c l u s i o n s of s u c h i n f e r e n c e s a r e likely to b e t r u e . F o r e x a m p l e , t h e a n a l o g u e of H u m e ' s position on induction remains possible. S o m e o n e may c o n c e d e that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is u n a v o i d a b l e for practical p u r p o s e s , w h i l e d e n y i n g that s u c h i n f e r e n c e c a n b e j u s t i f i e d . A n d w h i l e t h e y m a y b e p r e p a r e d to act as if t h e c o n c l u s i o n s of s u c h a r g u m e n t s w e r e t r u e — a g a i n for practical p u r p o s e s — t h e y m a y r e f u s e to a l l o w that t h e y are likely to be t r u e . S u c h a p e r s o n will h a p p i l y follow t h e w h o l e a r g u m e n t of this a n d t h e p r e c e d i n g c h a p t e r , a c c e p t i n g t h e c o n c l u s i o n s for practical p u r p o s e s o n l y . S o their s c e p t i c a l p o s i t i o n is j u s t a s intact at t h e e n d as it w a s at the b e g i n n i n g . y

W h i l e m y a r g u m e n t c a n n o t rationally c o n v i n c e t h e c o n v i n c e d s c e p t i c , w h a t I d o claim is that it s h o u l d c o n v i n c e all w h o a p p r o a c h the i s s u e w i t h an o p e n m i n d . All that is r e q u i r e d is that m y r e a d e r s h o u l d b e p r e p a r e d to u s e a n i n f e r e n c e to t h e b e s t e x p l a n a t i o n a n d b e l i e v e , at l e a s t t e n t a t i v e l y , that t h e c o n c l u s i o n is t r u e . T h i s n e e d n o t b e g a n y q u e s t i o n s in f a v o u r of t h e reliability of i n f e r e n c e to t h e b e s t e x p l a n a t i o n , s i n c e at this s t a g e it c a n b e left a s a n o p e n q u e s t i o n w h e t h e r or n o t i n f e r e n c e to t h e b e s t e x p l a n a t i o n is really reliable. T h e r e a d e r , like m y s e l f , m a y a p p r o a c h t h e m a t t e r p e r f e c t l y p r e p a r e d to b e c o n v i n c e d that i n f e r e n c e to t h e b e s t e x p l a n a t i o n is not r e l i a b l e , or to c o n c l u d e t h a t n o v e r d i c t c a n b e d e l i v e r e d e i t h e r w a y . B u t in fact, a s it t u r n s o u t , t h e b e s t u s e of o u r faculty of i n f e r e n c e to t h e b e s t 9

F o r a c o n t e m p o r a r y writer w h o a d o p t s just s u c h a position, see Bas v a n

F r a a s s e n , The Scientific

Image ( O x f o r d : O x f o r d U n i v e r s i t y P r e s s , 1 9 8 0 ) .

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Explanation

191

e x p l a n a t i o n l e a d s u s to t h e c o n c l u s i o n that s u c h i n f e r e n c e is g e n e r a l l y reliable. T h a t t h e sceptic c a n n o t b e d e f e a t e d d o e s n o t m e a n that t h e s c e p t i c w i n s . It s h o u l d c o m e a s n o s u r p r i s e that t h e r e a r e e p i s t e m o l o g i c a l s t a n d p o i n t s that are i m m u n e to rational p e r s u a s i o n . C o n s i d e r , for e x a m p l e , s o m e o n e w h o is a c o n v i n c e d p a r a n o i a c . O f c o u r s e n o t h i n g that w e say or d o can rationally r e q u i r e t h e m to give u p their b e l i e f t h a t all are c o n s p i r i n g a g a i n s t t h e m . F o r a n y t h i n g that w e say c a n i m m e d i a t e l y b e i n c o r p o r a t e d i n t o t h e p a r a n o i d h y p o t h e s i s , as b e i n g just o n e m o r e twist in t h e plot. Y e t this n e e d n o t m e a n — p l a i n l y — t h a t zve are n o t justified in b e l i e v i n g that t h e r e is n o plot. W h a t w e h a v e to r e c o g n i z e is that t h e task of e p i s t e m o l o g y is m o r e m o d e s t t h a n w e m i g h t initially h a v e t h o u g h t . T h e task c a n n o t be to p r o d u c e r e a s o n s for belief that will b e a c c e p t a b l e to a n y o n e , n o m a t t e r w h a t their starting p o i n t . It c a n o n l y b e to p r o d u c e r e a s o n s a c c e p t a b l e to t h o s e w h o h a v e n o t yet m a d e u p their m i n d s . S o w h i l e I c a n n o t claim to h a v e d e f e a t e d t h e s c e p t i c , I c a n claim t o h a v e sufficiently j u s t i f i e d a n o p p o s i n g r e a l i s m a b o u t o u r knowledge of the physical world.

Conclusion W H A T h a s e m e r g e d o v e r t h e last t w o c h a p t e r s is that it w a s a historical a c c i d e n t that m a n y of t h e classical e m p i r i c i s t s s h o u l d h a v e b e c o m e a t t a c h e d e i t h e r to s c e p t i c i s m or to p h e n o m e n a l i s m . It w a s their a n t i - n a t i v i s m a b o u t c o n c e p t s a n d a b o u t the c o n t e n t s of e x p e r i e n c e that led t h e m to p h e n o m e n a l i s m . A n d it w a s , u l t i m a t e l y , their a n t i - n a t i v i s m a b o u t c o n c e p t s (particularly the c o n c e p t of b e s t e x p l a n a t i o n ) that led t h e m to s c e p t i c i s m a b o u t the physical w o r l d . Y e t , a s I a r g u e d in c h a p t e r 9 , o p p o s i t i o n to n a t i v i s m w a s n e v e r really an e s s e n t i a l part of the e m p i r i c i s t e n t e r p r i s e . W h a t w a s crucial w a s r a t h e r o p p o s i t i o n to belief-acquisition p r o c e s s e s w h o s e reliability c a n n o t begin to be a c c o u n t e d for in natural t e r m s . N a t i v i s m w a s o n l y r e j e c t e d b e c a u s e a t h e o r y o f natural selection had n o t b e g u n to b e t h o u g h t of, a n d b e c a u s e the only available a c c o u n t of h o w i n f o r m a t i o n or c o n c e p t s m i g h t c o m e to be i n n a t e i n v o l v e d i n t e r v e n t i o n by G o d . It is, t h e n , a c o n s e q u e n c e of m y position that t h o s e later e m p i r i c i s t s , s u c h as Russell a n d A y e r , w h o c o n t i n u e d to o p p o s e n a t i v i s m a n d to b e attracted t o w a r d s s c e p t i c i s m or p h e n o m e n a l i s m , o n l y did s o b e c a u s e t h e y h a d lost t o u c h w i t h their e m p i r i c i s t r o o t s . T h e y s o m e h o w b e c a m e e n t a n g l e d in t h e sceptical or p h e n o m e n a l i s t p r o j e c t s of classical e m p i r i c i s m for their o w n s a k e s , n o t n o t i c i n g that t h o s e p r o j e c t s h a d o n l y a r i s e n w i t h i n e m p i r i c i s m a s part of a d e e p e r c o n c e r n — t h e c o n c e r n , n a m e l y , that c l a i m s to k n o w l e d g e s h o u l d b e c o n s t r a i n e d b y o u r b e s t naturalistic t h e o r i e s of t h e p o w e r s of t h e h u m a n m i n d , a n d of the m i n d ' s m o d e s of a c c e s s to reality. ( Q u i n e , o n t h e o t h e r h a n d , m a y b e s e e n to h a v e lost t o u c h w i t h t h e p r o j e c t of classical e m p i r i c i s m in a d i f f e r e n t w a y . I n s t e a d of r e q u i r i n g m e r e l y that epistemology should be consistent with science, he altogether d e n i e s t h e d i s t i n c t i o n b e t w e e n t h e m . In Q u i n e ' s v e r s i o n of n a t u r a l i s m , all t h e r e is to e p i s t e m o l o g y is s c i e n c e . B u t t h i s ,

Conclusion

193

i m p l a u s i b l y , j u s t r u l e s o u t of o r d e r a n y a t t e m p t to q u e s t i o n w h e t h e r s c i e n c e c a n really p r o v i d e u s w i t h k n o w l e d g e . ) W i t h t h e a d v e n t of a n a t u r a l t h e o r y of e v o l u t i o n , t h e r e w a s n o l o n g e r a n y n e e d for o p p o s i t i o n to n a t i v i s m . A n d o n c e certain k i n d s o f n a t i v i s m a r e a d m i t t e d as p l a u s i b l e , s o l u t i o n s to m a n y f o r m s of s c e p t i c i s m m a y d r o p out quite easily. It is also a g e n e r a l m o r a l of t h e s e last t w o c h a p t e r s that m u c h c o n t e m p o r a r y t h e o r y of k n o w l e d g e h a s e r r e d , particularly by failing to p a y d u e a t t e n t i o n to the traditional q u e s t i o n of t h e p o s s i b l e s o u r c e s of h u m a n k n o w l e d g e . M a n y h a v e b e c o m e ensnared into ever m o r e technical disputes concerning the c o n c e p t of k n o w l e d g e , w h i c h a r e largely irrelevant to the e p i s t e m o l o g i c a l t a s k — t o k n o w w h a t w e k n o w . T h e y h a v e also tried to s o l v e the p r o b l e m of s c e p t i c i s m directly, s e t t i n g a s i d e t h e i s s u e of the p o w e r s a n d faculties of t h e h u m a n m i n d ( i n c l u d i n g t h e q u e s t i o n of i n n a t e n e s s ) as of m i n o r s i g n i f i c a n c e . If the strategy of a r g u m e n t 1 h a v e p u r s u e d in t h e final t w o c h a p t e r s h a s b e e n c o r r e c t , h o w e v e r , t h e n this c o n c e n t r a t i o n of effort h a s b e e n a m i s t a k e . W i t h o u t c o n s i d e r i n g t h e g e n e r a l p o w e r s of the h u m a n m i n d w e c a n n o t h o p e to settle t h e q u e s t i o n of w h a t w e m a y k n o w o u r s e l v e s to k n o w . A n d o n l y if certain f o r m s of n a t i v i s m a r e a c c e p t e d , can w e justify r e a l i s m a b o u t o u r k n o w l e d g e o f the p h y s i c a l w o r l d . If there is o n e f u r t h e r m o r a l to b e d r a w n f r o m t h e s e c h a p t e r s — a s i n d e e d from this b o o k as a w h o l e — i t is this. O n l y by r e t u r n i n g to the historical r o o t s of o u r c o n t e m p o r a r y d e b a t e s , a n d by r e c o n s i d e r i n g t h e m o t i v e s that led p h i l o s o p h e r s to line u p o n e w a y or t h e o t h e r , h a v e w e f o u n d o u r w a y to w h a t , in m y v i e w , a r e p e r m a n e n t s o l u t i o n s to t h e p r o b l e m s of s c e p t i c i s m . T h o s e w h o d o n o t s t u d y t h e h i s t o r y of p h i l o s o p h y m a y easily c o m e to m i s l o c a t e their p r e s e n t p o s i t i o n o n the l a n d s c a p e , a n d t h u s b e m i s t a k e n a b o u t t h e p r o p e r a v e n u e s of e s c a p e . T h e overall c o n c l u s i o n of this b o o k is a s I i n d i c a t e d at t h e o u t s e t that it w o u l d b e — t h a t e m p i r i c i s m is a s v i b r a n t a n d d e f e n s i b l e t o d a y as it e v e r w a s . M y c o n t e m p o r a r y e m p i r i c i s m h a s b e e n s h o r n of t h e traditional o p p o s i t i o n to n a t i v i s m , y e t w i t h o u t l o s i n g t o u c h w i t h its e s s e n t i a l l y e m p i r i c i s t c o n c e r n s . I n d e e d , t h e r e is a s t r o n g c a s e for s a y i n g t h a t a n e m p i r i c i s t s h o u l d n o w a c c e p t t h e e x i s t e n c e of i n n a t e i n f o r m a t i o n - b e a r i n g m e n t a l s t r u c t u r e s (particularly r e l a t i n g to l a n g u a g e a n d v i s i o n ) ,

194

Conclusion

as w e l l a s t h e i n n a t e n e s s of at least s o m e c o n c e p t s a n d s o m e k n o w l e d g e . Y e t e m p i r i c i s m m a y still r e t a i n its traditional o p p o s i t i o n to p l a t o n i s m , a n d m o r e g e n e r a l l y to t h e i d e a that w e c a n o b t a i n s u b s t a n t i v e k n o w l e d g e b y r e a s o n a l o n e . In s u c h c a s e s t h e e m p i r i c i s t d e m a n d for a n a t u r a l e x p l a n a t i o n , of h o w o u r intellects c a n h a v e a c q u i r e d t h e p o w e r to o b t a i n for u s reliable i n f o r m a t i o n a b o u t s u b s t a n t i v e facts i n d e p e n d e n t of o u r t h o u g h t s , r e m a i n s in full force. N o r d o e s a n a p p e a l to n a t u r a l s e l e c t i o n p r o v i d e a rationalist w i t h a n y a d e q u a t e r e s p o n s e . T h e result of t h e s e c h a n g e s is that e m p i r i c i s m m a y n o w d r o p all its historical c o n n e c t i o n s w i t h s c e p t i c i s m or p h e n o m e n a l i s m , e m b r a c i n g instead a f o r m of r o b u s t r e a l i s m . M y c o n t e m p o r a r y e m p i r i c i s t m a y claim (partly via their a c c e p t a n c e o f n a t i v i s m ) that w e c a n k n o w o u r s e l v e s to k n o w that t h e r e is a p h y s i c a l w o r l d , a n d that w e c a n k n o w that w e h a v e k n o w l e d g e of m a n y facts a b o u t that w o r l d , b o t h particular a n d g e n e r a l . In t h e e n d , an e m p i r i c i s t is w h a t e v e r y o n e s h o u l d b e .

Further Reading Classics (available in m a n y e d i t i o n s a n d t r a n s l a t i o n s ) Plato, Republic (c.380 I K ) , e s p . b k s . 6 a n d 7; Meiw ( c . 3 8 0 HC); Phaedo

(c.380

BC).

D e s c a r t e s , R . , Discourse on the Method ( 1 6 3 7 ) ; Meditations on First Philosophy; ( 1 6 4 1 ) . L o c k e , J . , An Essay Concerning Human Understanding ( 1 6 9 0 ) . Leibniz, G . , New Essays Concerning Human Understanding ( 1 7 0 4 ) . Berkeley, G . , Principles of Human Knowledge ( 1 7 1 0 ) ; Three Dialogues between Hylas and Philonous ( 1 7 1 3 ) . H u m e , D . , A Treatise of Human Nature ( 1 7 3 9 ) , bk.i; Enquiry Concerning the Human Understanding ( 1 7 4 8 ) . K a n t , I., Critique of Pure Reason ( 1 7 8 1 ) ; Prolegomena to any Future Metaphysics

Platonism:

(1783).

For and Against

B e n a c e r r a f , P . , ' W h a t N u m b e r s C o u l d N o t B e ' , Philosophical 1965; ' M a t h e m a t i c a l T r u t h ' , Journal reprinted

of Philosophy,

in P. B e n a c e r r a f a n d H . P u t n a m

Mathematics,

(eds.),

2nd edn., Cambridge: Cambridge

Review,

1 9 7 3 . (Both a r e Philosophy

University

of

Press,

1983.)

Field, H . , Science without Numbers

( O x f o r d : Blackwell, 1 9 8 0 ) ;

Realism,

Mathematics and Modality ( O x f o r d : Blackwell, 1 9 8 9 ) . Frege,

G . , The Foundations

of Arithmetic,

trans. J. Austin

(Oxford:

Blackwell, 1 9 5 0 ) . H a l e , R . , Abstract Objects ( O x f o r d : Blackwell, 1 9 8 7 ) . Irvine, A . , ( e d . ) , Physicalism in Mathematics

(Dordrecht: Kluwer, 1990).

K a t z , ] . , Language and Other Abstract Objects ( O x f o r d : Blackwell, 1 9 8 1 ) . W r i g h t , C , Frege's Conception of Numbers as Objects ( A b e r d e e n : A b e r d e e n U n i v e r s i t y P r e s s , 1 9 8 3 ) . ( 2 n d E d n . , O x f o r d : Blackwell, 1 9 9 1 . )

Nativism:

For and Against

Block, N . ( e d . ) , Essays in Philosophy of Psychology,

n (London: Methuen,

1981), pt. 4.

C h o m s k y , N . , Language and Problems of Knowledge M I T P r e s s , 1 9 8 8 ) , c h s . 1, 2 a n d 5 .

(Cambridge, Mass.:

Further

196 F o d o r , J . , Representations

Reading

(Brighton: Harvester, 1981), c h . 1 0 ;

Psychose-

mantics ( C a m b r i d g e , M a s s . : M I T P r e s s , 1 9 8 7 ) , c h . l a n d e p i l o g u e . Searle, ] . , ( e d . ) ,

Philosophy

of Language

(Oxford: Oxford

University

(Berkeley,

Calif.: California

University

P r e s s , 1 9 7 1 ) , p t . vu. Stich,

S., ( e d . ) , Innate

Ideas

Press, 1975).

The Nature

of

Knozoledge

B o n j o u r , L . , The Structure

of Empirical

Knowledge

(Cambridge,

Mass.:

Harvard University Press, 1985). C r a i g , E . , Knowledge

and the Slate of Nature ( O x f o r d : O x f o r d University

Press, 1990). D a n c y , J . , Introduction

to Contemporary

Epistemology

( O x f o r d : Blackwell,

1985), c h s . 2 - 4 , 8, a n d 9. G o l d m a n , A . , Epistemology

ami Cognition

(Cambridge, Mass.: Harvard

University P r e s s , 1986), pt. 1. I . i ' h r e r , K., Theory of Knowledge ( L o n d o n : R o u t l e d g e , 1990). No/.ick, T . , Philosophical

Explanations

( O x f o r d : O x f o r d University P r e s s ,

1981), c h . 3 .

Scepticism:

For and

Against

B o n j o u r , L . , The Structure

of Empirical

Knowledge

(Cambridge,

Mass.:

H a r v a r d University P r e s s , 1 9 8 5 ) , c h . 8 . D a n c y , ] . , Introduction

to Contemporary

Epistemology

( O x f o r d : Blackwell,

1985), c h s . l , 5, 9, 1 0 - 1 3 . I l o o k w a y , C , Scepticism ( L o n d o n : R o u t l e d g e , 1 9 9 0 ) . L y c a n , W . , judgement

and justification

(Cambridge: Cambridge Univer-

sity P r e s s , 1 9 8 8 ) , p t . 2. S t r o u d , B . , The Significance

of Philosophical

Scepticism

(Oxford: Oxford

University Press, 1984). Swinburne,

R., (ed.),

The justification

of Induction

(Oxford:

Oxford

University Press, 1974). U n g e r , P . , Ignorance: Press, 1975).

A Case for Scepticism

(Oxford: Oxford University

Index a priori k n o w l e d g e 4 , 9 - 1 3 , 1 8 , 2 0 , 7 8 , 132, 1 4 3 - 6 , 1 5 5 - 7 abstraction 5 4 - 6 , 59, 100 a n a l y t i c 10, 1 2 , 3 4 , 3 6 , 6 6 - 7 , 1 7 8 - 9 Aristotle 1 7 , 2 8 A r m s t r o n g , D . 2 8 , 5 8 , 1 7 8 n. a s t r o l o g y 1 3 8 , 141 A y e r , A . 8 n . , 12, 1 5 9 , 1 9 2 B a c o n , F.

14

belief n a t u r e of 4 9 , 9 0 , 9 6 non-conscious 89-90, 97 B e n a c e r r a f , P. 3 8 B e r k e l e y , G . 5, 1 4 , 5 8 , 5 9 , 9 2 n . , 1 3 3 , 159 best explanation c o n c e p t of 1 0 7 - 8 , 181, 186 of experience 1 6 6 - 7 0 inference to 68, 1 6 5 - 6 , 186, 190 innate c o n c e p t of 1 0 7 - 1 0 , 1 7 5 , 1 8 1 of i n n a t e n e s s 1 8 3 - 6 reliability o f 1 7 4 , 1 8 1 - 7 , 1 9 0 - 1 Buckle, S 1 3 4 n . c a p a c i t y , p r a c t i c a l 8 8 - 9 , 101 Cartesian 120, 1 2 4 - 5 see also D e s c a r t e s , R. c a u s a l t h e o r y of k n o w l e d g e 7 2 - 3 cause, c o n c e p t of 4 3 , 5 7 - 8 C h o m s k y , N. 9, 15, 8 1 - 9 1 , 92 n., 99, 101, 1 0 3 - 4 , 107, 113, 125, 148 Christian(ity) 62, 68 see also C h u r c h Church 61, 130 c o h e r e n c e c o n c e p t i o n of t r u t h 6 - 7 c o h e r e n t i s m 4, 6 7 - 9 , 1 8 7 - 9 concepts and abstraction 5 4 - 6 6 acquisition of 5 - 6 , 5 4 - 6 1 , 1 0 5 - 6 , 162 complex 5 6 - 8 a s c o m p o n e n t s o f belief 9 6 - 7 , 9 8 , 105-6

conscious 55-6, 9 7 - 8 as discriminatory capacities 9 5 - 6 , 9 7 - 8 , 102 k n o w l e d g e of our o w n 1 6 4 , 1 8 8 a n d linguistic training 6 0 - 1 , 106 n a t u r e of 5, 3 3 - 4 , 4 1 , 1 0 0 - 1 , 1 0 4 - 7 , 108 psychological 107, 1 2 4 - 6 simple 5 9 - 6 0 see also b e s t e x p l a n a t i o n ; i n n a t e concept; prototype conceptual pragmatism 7 0 - 1 , 172 conscious thought 97 C o o k , V. 8 1 n . c o r r e s p o n d e n c e theory of truth C r a i g , E . 71 n.

6-8

D a n c y , J. 6 n . Davies, M. 91 n. D e n n e t t , D . 1 4 0 n. D e s c a r t e s , R. 2, 4 , 9 , 5 6 , 5 9 , 7 7 , 1 6 2 see also C a r t e s i a n D u m m e t t , M. 8 n. empiricism and anti-nativism 6 1 - 3 , 1 2 7 - 8 , 130, 142, 193 c h a r a c t e r i s t i c t h e s e s o f 4 - 6 , 8 - 9 , 13 classical 2, 1 3 , 1 4 - 1 5 , 1 6 , 5 8 , 6 9 , 9 4 , 192-3 core of 1 3 - 1 6 , 1 2 7 - 3 5 , 1 4 1 - 2 , 1 9 2 - 4 see also a p r i o r i k n o w l e d g e ; i n n a t e ; phenomenalism; scepticism evolution 7 7 - 8 , 9 3 , 110, 113, 1 2 1 - 2 , 123, 142, 144, 147, 149, 151, 152, 156 see also n a t u r a l s e l e c t i o n Field, H. 1 3 , 2 4 - 7 F o d o r , J. 9 , 1 5 , 8 0 n . , 1 0 0 - 5 , 1 1 6 n . , 118 folk-psychology 115-18 concepts 124-6 correctness of 1 2 1 , 1 2 2 ^ 1

198

Index

folk-psychology (coif.) i n n a t e n e s s of 1 1 9 - 2 2 universality of 1 1 8 - 1 9 foundationalism 4, 67, 1 6 2 - 4 , 188 F r e g e , C . 2 0 , 3 6 , 3 8 n. F r e u d , S. 4 9 functionalism 125

justificationalism 6 4 - 7 , 6 9 - 7 2 , 7 4 - 7 , 131 n . , 1 6 3 K a n t , I. 1 3 5 n . , 1 5 5 - 7 Katz,). 30n., 145-6 KK thesis 7 4 - 5 , 144 knowledge analysis of 2 - 3 , 49, 53, 64, 72, 7 3 ,

G e t t i e r , E. 71 n. God

1 6 , 17, 1 8 , 2 6 , 5 6 , 6 8 , 7 7 , 7 8 , 1 1 1 , 130, 131, 132, 133, 134, 1 5 3 - 5 , 192 G o l d m a n , A. 7 3 n . , 7 4 n . , 7 6 n . , 1 3 2 n .

H a l e , K. 2 6 n. H e l l m a n , G. 3 8 H o b b e s , T . 14 H u m e , D. 2, 5 , 9, 14, 5 7 - 8 , 6 1 , 1 0 3 , 1 0 8 - 9 , 1 3 0 n . , 1 3 3 , 1 3 4 - 5 , 159, 176, 1 8 1 , 190

imagism 5 - 6 , 34 induction 109, 176

171,193 e x t e n t of 1 - 2 , 1 3 3 , 1 7 4 - 5 , 1 9 4 o r d e r s of 7 4 - 7 , 1 6 0 , 1 6 3 - 4 , 1 6 6 as p u r p o s e relative 6 5 , 1 7 2 - 3 s o u r c e s of 2 - 3 , 1 9 3 see also a priori k n o w l e d g e : c a u s a l t h e o r y of k n o w l e d g e : c o h e r e n t ism; foundationalism; innate k n o w l e d g e ; justificationalism; reliabilism; scepticism; s u b s t a n tive k n o w l e d g e Lnkoff, G. 1 0 5 n. l a n g u a g e of t h o u g h t 1 0 1 - 2 learning 52, 7 9 - 8 1 , 82, 85, 100, 103

H u m e on 1 0 8 - 9 justification of 1 7 6 - 8 1 i n f e r e n c e to b e s t e x p l a n a t i o n , see b e s t

L e i b n i z , G. 2 , 9 L e o n , M . 2 0 n. linguistic universals 8 3 - 4 L o c k e , J . 2, 4 , 5 , 1 4 , 1 5 , 17, 4 8 - 5 6 , 6 1 ,

explanation i n n a t e beliefs 6 5 s u r v i v a l v a l u e of 1 1 1 - 1 3 , 1 2 3 - 4 i n n a t e c o n c e p t s 8, 5 3 - 6 1 , 9 9 - 1 1 0 , 124-5

64, 69, 77, 7 8 , 1 0 0 , 1 0 3 , 1 2 8 , 1 3 3 4 , 1 3 5 n., 140, 159 logical n o t i o n s , i n n a t e n e s s of 1 0 5 logicism 36, 147 L o r e n z , K. 1 8 3 n.

sec also c o n c e p t s i n n a t e f a c u l t i e s of m i n d 9 , 7 9 - 8 1 , 161 innate information bearing mental s t r u c t u r e s 8, 8 1 - 6 , 9 1 - 4 , 1 6 1 - 2 versus knowledge 87-91 innate knowledge 8 , 4 8 , 1 1 3 - 1 4 a n d a priori 7 8 , 1 4 3 and concepts 53^1 as developmentally determined 50-2 of f o l k - p s y c h o l o g y 5 2 , 1 1 9 - 2 1 , 1 2 4 , 144 as generally triggered 5 1 , 54 of g r a m m a r 5 2 , 8 7 - 9 1 as latent 4 9 a s locally t r i g g e r e d 5 2 , 5 4 , 8 2 , 1 2 1 of m a t h e m a t i c s 4 6 - 7 , 1 4 5 - 5 3 possibility of 6 4 - 7 , 69, 7 7 - 8 , 164 as stored propositions 50, 54 introspection 120-1, 124-5 intuition, intellectual 1 9 - 2 0 , 4 3 ^ , 127 128, 132, 1 4 5 - 6

M a d d y , P. 2 4 n. M a r r , D . 9 2 n. mathematics as analytic 10 as empirical 1 1 - 1 2 falsity of 1 3 , 2 4 - 7 k n o w l e d g e of 1 9 , 2 5 , 1 4 5 - 5 3 as mind-dependent 39^42 r e d u c t i o n to logic 3 6 - 9 usefulness of 10, 2 4 - 5 , 47, 1 4 9 - 5 2 see also i n t u i t i o n , i n t e l l e c t u a l ; numbers; platonism Mill, J. 11 n a t i v i s m , see i n n a t e natural kind term 1 2 5 - 6 natural law doctrine 134 n a t u r a l s e l e c t i o n , reliability of 7 8 , 1 1 1 - 1 3 , 1 2 4 , 1 4 9 , 1 5 1 - 2 , 1 5 3 - 4 , '. 160, 1 8 3 - 6 see also e v o l u t i o n

199

Index n a t u r a l i s m 9, 16, 4 5 , 108, 1 1 1 , 130, 1 3 1 - 2 , 134, 141, 146, 159, 192 N e e d h a m , R. 1 1 9 Nelkin, N. 2 0 n . N o z i c k , R. 7 2 n. numbers as abstract individuals 2 0 - 4 as m i n d - d e p e n d e n t 3 6 , 3 9 - 4 2 a s m i n d - i n d e p e n d e n t 31 as necessarily existing 1 8 - 1 9 , 3 2 see also m a t h e m a t i c s ; p l a t o n i s m o b j e c t i v i t y 7 - 8 , 12, 3 0 - 2 , 3 4 - 5 paradigm, perceptual 106 parameter, grammatical 83, 85, 114 P e a c o c k e , C . 91 n. p h e n o m e n a l i s m 1 - 2 , 4 - 5 , 39, 129, 157, 1 5 9 - 6 2 , 1 9 2 , 1 9 4 P l a t o 2, 9 , 2 0 , 5 6 , 8 4 , 1 2 5 p l a t o n i s m 10, 17, 1 8 - 1 9 a n d causal role 4 3 - 5 , 150 and knowledge 1 9 - 2 0 , 2 4 - 6 , 4 3 ^ , 145-53 and rationalism 1 7 - 1 8 and scepticism 4 5 - 7 , 152 see also m a t h e m a t i c s ; n u m b e r s Plato's Problem 8 4 - 5 , 9 9 - 1 0 0 , 104, 107, 1 1 9 - 2 1 P o p p e r , K. 3 9 n. practical-reasoning-model 89-90, 96, 102, 118, 123 p r e s c i e n c e 1 3 7 - 4 0 , 141 prototype 104-7 p s y c h o l o g y (scientific) 8 0 , 1 2 6 , 1 3 0 , 1 3 2 - 3 , 134 Quine, W.

11, 1 7 n . , 1 3 0 n . , 161 n.,

185 n., 192 r a t i o n a l i s m , c l a s s i c a l 2, 1 7 - 1 8 , 6 9 , 153-5 realism about folk-psychology

117

about knowledge 91

1,8,167-70,187-

about truth 7-8, 156, 189 reliabilism 7 1 , 7 3 - 4 , 7 6 - 7 , 1 3 1 , 1 3 6 , 163-4 R u s s e l l , B. 3 8 n . , 1 5 9 , 1 9 2 s c e p t i c i s m 1 - 3 , 16, 4 5 - 7 , 7 0 , 1 5 9 - 6 0 , 1 6 2 - 3 , 170, 1 7 4 - 5 , 1 8 8 - 9 , 1 9 0 - 1 , 1 9 2 - 3 , 194 science 25, 45, 108, 1 2 5 - 6 , 130, 1 3 6 - 7 , 1 7 4 - 5 , 184, 1 9 2 - 3 a d e q u a c y of 1 3 1 , 1 3 9 - 4 2 e a r l y c o n c e p t i o n of 8 0 self-evidence

66-7

s e n t e n c e s , existence of 2 9 - 3 0 simplicity 1 6 9 - 7 0 , 1 8 3 - 4 S m i t h , A . 8 0 n. S t i c h , S. 1 1 8 , 1 2 2 n . S t r a w s o n , P . 9 n. s u b s t a n t i v e k n o w l e d g e 10, 1 3 , 1 7 - 1 8 , 29, 31, 33, 67, 114, 124, 143, 145, 146, 157 transcendental argument 155-6 idealism 1 5 6 - 7 universals 2 abstract 2 8 - 9 existence of 2 7 - 9 i m m a n e n t 28, 36 m i n d - i n d e p e n d e n c e of 30 necessary existence of 32 reduction of 3 3 - 5 Urquhart, A. 25 n. van Fraassen vision

1 9 0 n.

91-4

W a l k e r , S. 9 5 n . W e l l m a n , H . 1 2 0 n. W i t t g e n s t e i n , L. 1 2 , 1 1 9 , 1 7 1 n. Woodfield, A . 106 n. Wright, C. 8 n . , 1 2 n . , 3 8

C o n t e m p o r a r y debates in epistemology devote much attention to the nature o f knowledge, but neglect the question o f its sources. The distinctive focus o f Human Knowledge and Human Nature is on the latter, especially on the question o f innateness. Peter Carruthers's aim is to transform and reinvigorate contemporary empiricism, while also providing an introduction to a range o f issues in the theory o f knowledge. He gives a lively presentation and assessment o f the claims o f classical empiricism, particularly its denial o f substantive a priori knowledge and also o f innate knowledge. He argues that we would be right to reject the substantive a priori but not innateness, and then presents a novel account o f the main motivation behind empiricism, which leaves contemporary empiricists free to accept innate knowledge and concepts. H e closes with a discussion o f scepticism, arguing that acceptance o f innate concepts may lead to a decisive resolution o f the problem in favour o f realism. T h e book will be o f equal interest to students o f the history o f modern philosophy and the theory o f knowledge, and their teachers. It provides a new way o f looking at classical empiricism, and should lead to a renewal o f interest in the innateness issue in epistemology. P e t e r C a r r u t h e r s is Senior Lecturer in Philosophy at the University o f Sheffield. He is the author of The Metaphysics of the 'Tractatus' (1990), Tractarian Semantics: Finding Sense in Wittgenstein's 'Tractatus' (1989), and Introducing Persons: Theories and Arguments in the Philosophy of Mind (1986). O X F O R D U N I V E R S I T Y PRESS

19-875102-8

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