650 15 165KB
Pages 11 Page size 595 x 792 pts Year 2007
A Reply to Brian Loar's "Must Beliefs Be Sentences?" Jerry Fodor PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association, Vol. 1982, Volume Two: Symposia and Invited Papers. (1982), pp. 644-653. Stable URL: http://links.jstor.org/sici?sici=0270-8647%281982%291982%3C644%3AARTBL%22%3E2.0.CO%3B2-O PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association is currently published by The University of Chicago Press.
Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/about/terms.html. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/journals/ucpress.html. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission.
JSTOR is an independent not-for-profit organization dedicated to and preserving a digital archive of scholarly journals. For more information regarding JSTOR, please contact [email protected].
http://www.jstor.org Sat May 12 01:03:33 2007
A Reply t o B r i a n L o a r ' s "Must Be1 i e f s Be Sentences?" J e r r y Fodor Massachusetts I n s t i t u t e o f Technology
I n t h e p a r t s o f h i s paper t h a t I ' l l be concerned w i t h here, B r i a n Loar c o n t r a s t s two accounts o f t h e n a t u r e o f b e l i e f s . A c c o r d i n g t o t h e f i r s t , be1 i e f s (and, m u t a t i s mutandi s, 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 ) a r e mental s t a t e s t h a t a r e i n d i v i d u a t e d by r e f e r e n c e t o t h e i r f u n c t i o n a l r o l e (a f u n c t i o n a l r o l e , i n t u r n , i s a p a t t e r n o f causal r e l a t i o n s t h a t a mental s t a t e b e a r s t o a n o r g a n i s m ' s p r o x i m a l i n p u t s and o u t p u t s and t o i t s o t h e r mental s t a t e s ) . A c c o r d i n g t o t h e second account, a b e l i e f i s a r e l a t i o n a l s t a t e o f which t h e r e l a t a a r e , on t h e one hand, t h e organism which e n t e r t a i n s t h e b e l i e f s , and on t h e o t h e r a mental r e p r e s e n t a t i o n . We n e e d n ' t , f o r p r e s e n t purposes, w o r r y much a b o u t what s o r t s o f t h i n g s mental r e p r e s e n t a t i o n s a r e ; f o r o r i e n t a t i o n , t h i n k o f mental p a r t i c u l a r s which serve something l i k e t h e f u n c t i o n t h a t was a s s i g n e d t o " I d e a s " i n c l a s s i c a l e m p i r i c i s t e p i s t e mology. L i k e Ideas, mental r e p r e s e n t a t i o n s a r e supposed t o be possessed s i m u l t a n e o u s l y o f causal and semantic p r o p e r t i e s ; mental r e p r e s e n t a t i o n s a r e t h e r e f o r e s p e c i e s o f symbols. However, mental r e p r e s e n t a t i o n s a r e u n l i k e Ideas i n t h a t t h e y a r e u s u a l l y t a k e n t o be s t r u c t u r e d i n some way analogous t o t h e s t r u c t u r e o f n a t u r a l language sentences. Mental r e p r e s e n t a t i o n s , t h a t i s t o say, a r e supposed t o be species o f d i s c u r s i v e r a t h e r t h a n i c o n i c symbols. I t i s because o f t h i s l a t t e r f e a t u r e o f mental r e p r e s e n t a t i o n t h e o r y t h a t t h e metaphor o f a language o f t h o u g h t seems a p p o s i t e . Loar a p p a r e n t l y t a k e s i t t h a t t h e f u n c t i o n a l r o l e a c c o u n t o f b e l i e f s and t h e mental r e p r e s e n t a t i o n a c c o u n t o f b e l i e f s are, as i t were, f r i e n d l y c o m p e t i t o r s . For though t h e two t h e o r i e s c l e a r l y have a l o t i n common, and though Loar acknowledges t h a t i t c o u l d t u r n o u t t h a t b o t h a r e t r u e , s t i l l he i s i n c l i n e d t o b e l i e v e t h a t t h e arguments f a v o r i n g t h e f u n c t i o r l a l r o l e s t o r y a r e i n b e t t e r shape t h a n t h o s e t h a t f a v o r mental r e p r e s e n t a t i o n s . Indeed, Loar p r e s e n t s a number o f cons i d e r a t i o n s t h a t a r e supposed t o m i l i t a t e f o r t h e f o r m e r as a g a i n s t t h e l a t t e r . By c o n t r a s t , my view (and t h e burden o f my argument i n t h i s commentary) i s t h i s : t h e two accounts are, t o a l l i n t e n t s and
6
PSA 1982, V lume 2, pp. 644-653 1983 by t h e P h i l o s o p h y o f Science A s s o c i a t i o n Copyright
purposes, i n s e p a r a b l e . On t h e one hand, t h e mental r e p r e s e n t a t i o n approach i m p l i c i t l y commits one t o i n d i v i d u a t i n g mental s t a t e s by t h e i r f u n c t i o n a l r o l e s ; and, on t h e o t h e r , i t 1 ' s o n l y by e n d o r s i n g t h e mental r e p r e s e n t a t i o n view t h a t we can make c l e a r how a f u n c t i o n a l r o l e t h e o r y o f p r o p o s i t i o n a l a t t i t u d e s c o u l d be t r u e . Well, t o g e t t o d e t a i l s , L o a r ' s p i c t u r e seems t o be as f o l l o w s : somebody who i s i n t o mental r e p r e s e n t a t i o n s could, a t h i s d i s c r e t i o n , a l s o embrace a f u n c t i o n a l r o l e a c c o u n t o f t h e i v i d u a t i o n o f b e l i e f s . A f t e r a l l , mental r e p r e s e n t a t i o n s a r e supposed t o have causal p r o p e r t i e s , so r e f e r e n c e t o mental r e p r e s e n t a t i o n s m i g h t come i n t o a t h e o r y by way o f answering t h e q u e s t i o n : 'what p r e c i s e l y i s i t t h a t has t h e f u n c t i o n a l r o l e t h a t , a c c o r d i n g t o f u n c t i o n a l r o l e theorists, provides the i n d i v i d u a t i o n condition f o r the b e l i e f t h a t P ? ' Answer: i t i s a c e r t a i n r e l a t i o n a l s t a t e ; v i z . , t h e v e r y r e l a t i o n a l s t a t e whose r e l a t a a r e t h e b e l i e v i n g organism and an approp r i a t e mental s y m b o l ( s eabove). e But, though Loar sees t h a t a a c c e p t t h e view t h a t t h e r e i s mental r e p r e s e n t a t i o n t h e o r i s t some f u n c t i o n a l l y i n d i v i d u a t e d mental s t a t e t h a t a l l and o n l y Pbe1 i e v e r s share (some mental s t a t e w i t h an " i n t e r p e r s o n a l l y a s c r i b a b l e " f u n c t i o n a l r o l e , as L o a r p u t s i t ) , s t i l l he h o l d s t h a t t h i s would be a n excresence on t h e mental r e p r e s e n t a t i o n t h e o r y .
could
What I t a k e i t t h a t Loar has i n m i n d h e r e i s t h a t even i f t h e mental r e p r e s e n t a t i o n t h e o r i s t has t h e o p t i o n o f i n d i v i d u a t i n g b e l i e f s b y t h e i r f u n c t i o n a l r o l e s , s t i l l he a l s o has a n o t h e r o p t i o n ; v i z . , t h a t o f i n d i v i d u a t i n g b e l i e f s by r e f e r e n c e t o t h e c h a r a c t e r o f t h e m e n t a l symbols t h a t t h e organism i s a l l e g e d l y r e l a t e d t o when i t has t h e b e l i e f s . Suppose ( p e r i m p o s s i b l e ) t h a t we t h i n k i n E n g l i s h , so t h a t b e l i e v i n g t h a t i t ' s o i n g t o r a i n i s bearing a c e r t a i n s p e c i f i e d r e l a t i o n ( c a l l i t R*) t o t h e E n g l i s h sentence " i t ' s g o i n g t o r a i n " . Then we can say what i t i s t o have t h e b e l i e f t h a t i t ' s g o i n g t o r a i n w i t h o u t s p e c i f y i n g t h e f u n c t i o n a l r o l e o f t h a t b e l i e f . I n f a c t , we j u s t d i d : i t ' s t o bear R* t o " i t ' s g o i n g t o r a i n " . So t h a t ' s t h e sense i n which Loar t h i n k s t h a t t h e f u n c t i o n a l r o l e s t o r y i s " s t r o n g e r " t h a n t h e mental r e p r e s e n t a t i o n s t o r y : a c c o r d i n g t o t h e former, b u t n o t t h e l a t t e r , b e l i e f - t h a t - i t ' s - g o i n g - t o - r a i n a s c r i p t i o n s i m p l y t h a t t h e r e i s a n i n t e r p e r s o n a l l y shared f u n c t i o n a l r o l e t h a t a l l and o n l y b e l i e f s - t h a t - i t ' s - g o i n g - t o - r a i n have i n common.
I t h i n k , however, t h a t t h i s way o f v i e w i n g t h e s i t u a t i o n i s m i s leading. For i n order t o divorce the i n d i v i d u a t i o n conditions f o r b e l i e f s f r o m t h e s a t i s f a c t i o n o f some i n t e r p e r s o n a l l y a s c r i b a b l e f u n c t i o n a l r o l e , t h e mental r e p r e s e n t a t i o n t h e o r i s t would need t o have a NONFUNCTIONAL c r i t e r i o n f o r t h e t y p e - t o k e n r e l a t i o n f o r mental r e p r e s e n t a t i o n s . Pnd we have n o t g o t such a c r i t e r i o n and, i n my view, i t i s most u n l i k e l y t h a t we a r e g o i n g t o g e t one. Here i s t h e p o i n t i n a n u t s h e l l . Suppose t h a t tokens o f t h e b e l i e f t h a t i t ' s r a i n i n g a r e t o be i d e n t i f i e d w i t h t o k e n i n g s o f t h e f o r m u l a F w h i l e t o k e n s o f t h e b e l i e f t h a t i t ' s snowing a r e t o be i d e n t i f i e d
w i t h t o k e n i n g s o f t h e f o r m u l a G. Then, presumably, we can d i s t i n g u i s h between t h e b e l i e f s i f we can d i s t i n g u i s h between t h e c o r r e s ponding tokens; i n p r i n c i p l e , t h e t y p e l t o k e n r e l a t i o n f o r mental symbols p r o v i d e s a c r i t e r i o n f o r t h e i n d i v i d u a t i o n o f b e l i e f s i f t h e mental r e p r e s e n t a t i o n a c c o u n t o f b e l i e f s i s t r u e . B u t now, how i s t h e t y p e - t o k e n d i s t i n c t i o n f o r mental symbols t o be drawn? Not, p r e sumably, o r t h o g r a p h i c a l l y o r a c o u s t i c a l l y as i n t h e case o f w r i t t e n / spoken t o k e n i n g s o f E n g l i s h sentences. Even i f we t h i n k i n E n g l i s h , t o k e n t h o u g h t s a r e s u r e l y n o t sequences o f graphemes o r phones. So, t h e n , presumably some o t h e r way. I f you a c c e p t t y p e p h y s i c a l i s m , you may suppose t h a t mental r e p r e s e n t a t i o n s o f t h e same ( a s i t were) l i n g u i s t i c t y p e a r e i p s 0 f a c t o p h y s i c a l events o f t h e same n e u r a l t y p e . But few mental r e p r e s e n t a t i o n t h e o r i s t s a c c e p t t y p e p h y s i c a l i s m ; and, even t h o s e who do presumably d o n ' t want t h e t h e o r y o f b e l i e f t o e n t a i l it. T h i s means, so f a r as I can see, t h a t t h e o n l y o p t i o n i s t o assume t h a t t h e t y p e / t o k e n r e l a t i o n f o r mental r e p r e s e n t a t i o n s i s i t s e l f f u n c t i o n a l l y s p e c i f i e d . What makes something a t o k e n o f t h e mental symbol " i t ' s r a i n i n g " i s t h e causal p r o p e r t i e s o f t h e symbol r a t h e r t h a n i t s shape, charge o r b i o c h e m i c a l p e c u l i a r i t i e s . B u t i f t h a t i s t r u e then, i n p r a c t i c e a t l e a s t , t h e mental r e p r e s e n t a t i o n t h e o r i s t i s c o m n i t t e d t o much t h e same c l a i m s a b o u t i n t e r p e r s o n a l f u n c t i o n a l r o l e s as h i s e r s t w h i l e a n t a g o n i s t . So f a r , mental r e p r e s e n t a t i o n t h e o r i s t s and f u n c t i o n a l r o l e t h e o r i s t s l o o k as i f t h e y s i n k o r swim t o g e t h e r . N e v e r t h e l e s s , I agree w i t h Loar t h a t t h e mental r e p r e s e n t a t i o n s t o r y i s i n some sense t h e more adventurous o f t h e two. I n p r i n c i p l e , we c o u l d i d e n t i f y b e l i e f s w i t h s t a t e s t h a t have c h a r a c t e r i s t i c f u n c t i o n a l r o l e s w i t h o u t g o i n g on t o t r y and say, as mental r e p r e s e n t a t i o n t h e o r i s t s do, what t h e (as i t were) i n t e r n a l c o m p o s i t i o n o f such s t a t e s may be. B u t I t h i n k , f o r two reasons, t h a t t h a t would be a bad i d e a . F i r s t , what i s so good a b o u t n o t b e i n g adventurous? It i s h a r d l y t h a t t h e e x c i t e m e n t o f p h i l o s o p h i c a l s p e c u l a t i o n , however venturesome,is l i k e l y t o s t r a i n even a d e l i c a t e nervous s e n s i b i l i t y ; and t h e r e i s t h e Popperian p o i n t t h a t c o n f i r m i n g a s t r o n g h y p o t h e s i s i s ipso f a c t o more i l l u m i n a t i n g t h a n c o n f i r m i n g a weak one. Second, n o t a s k i n g u e s t i o n i s n o t a way o f answering it, and, sooner o r l a t e r , t h e f u n c t i o n a l r o l e t h e o r i s t i s g o i n g t o have t o say something about have t h e f u n c t i o n a l r o l e s t h a t he t a k e s t o what k i n d o f s t a t e s be a p p r o p r i a t e t o t h e i n d i v i d u a t i o n o f be1 i e f s . I f , i n p a r t i c u l a r , no s t a t e s c o u l d have t h e r i g h t causal p r o p e r t i e s , t h e n t h e f u n c t i o n a l r o l e t h e o r i s t i s i n t h e soup. My p o i n t i s t h a t , as t h i n g s stand, t h e r e l a t i o n s - t o - d i s c u r s i v e - s y m b o l s s t o r y i s t h e o n l y p l a u s i b l e one a b o u t what t h e s t r u c t u r e o f such f u n c t i o n a l s t a t e s c o u l d be.
could
LOar L e t me g i v e j u s t one reason why I t h i n k t h a t t h i s i s so. o f f e r s , as one o f t h e prima f a c i e arguments f o r mental r e p r e s e n t a t i o n s , t h e f o l l o w i n g consideration. " B e l i e f s have common s t r u c t u r e s and s t r u c t u r e d r e l a t i o n s t o each o t h e r , f o r example, t h e r e l a t i o n between t h e b e l i e f t h a t q & p and t h e b e l i e f t h a t p , w h i c h a r e essent i a l t o t h e i r r o l e i n psychological explanation. That s t r u c t u r e i s
l a n g u a g e - l i k e ; hence, t h e argument goes, i f i t i s r e a l i z e d t h e r e i s a language o f t h o u g h t . " ( p . 6 3 5 ) . However, L o a r r e p l i e s , we need n o t i n f e r f r o m t h e e x i s t e n c e o f (as i t were) l o g i c a l f o r m i n b e l i e f s t o t h e e x i s t e n c e o f mental symbols. Rather, what a l l c o n j u n c t i v e b e l i e f s ( f o r example) have i n common m i g h t j u s t be " . . . t h e i r conceptual r e l a t i o n s t o o t h e r a p p r o p r i a t e l y indexed b e l i e f s , and n o t ( n e c e s s a r i l y ) t h e i r f i r s t - o r d e r s t r u c t u r e . " ( p . 636). Now, f o r s t a r t e r s , I do n o t t h i n k t h a t " c o n c e p t u a l " r e l a t i o n s t o o t h e r b e l i e f s can be what Loar a c t u a l l y i n t e n d s . For one t h i n g , t h e n o t i o n o f conceptual r e l a t i o n i s u n r e c o n s t r u c t e d i n h i s t h e o r y so i t i s n o t one t o which Loar i s , s t r i c t l y speaking, e n t i t l e d . And, f o r a n o t h e r t h i n g , I suppose t h e conceptual r e l a t i o n s o f a c o n j u n c t i v e b e l i e f would be i d e n t i c a l t o t h o s e o f any l o g i c a l l y e q u i v a l e n t Ec o n j u n c t i v e b e l i e f ; whereas, presumably, one wants a t h e o r y o f p r o p o s i t i o n a l a t t i t u d e t o d i s t i n g u i s h between, say, t h e b e l i e f t h a t P & Q and t h e b e l i e f t h a t ( ( P & -P) V (P & Q ) ) . What L o a r ' s t h e o r y does have t o o f f e r - and what I presume Loar has i n mind - must be t h a t c o n j u n c t i v e ( e t c . ) b e l i e f s have t h e i r conj u n c t i v e structure i n v i r t u e o f t h e i r causal/functional r e l a t i o n t o o t h e r f u n c t i o n a l l y i n d i v i d u a t e d mental s t a t e s . But that r e p l y , though i t i s one L0ar i s i n a p o s i t i o n t o make, r e a l l y misses t h e p o i n t o f t h e problem. The p o i n t o f t h e problem i s t h i s : complex b e l i e f s a r e complex i n a way t h a t c r i e s o u t f o r some e x p l i c a t i o n o f t h e i r s t r u c t u r e i n terms o f c o n s t i t u e n c y r e l a t i o n s . I t l o o k s , t o p u t i t as c r u d e l y as p o s s i b l e , as though t h e b e l i e f t h a t P & Q ought t o have something P - i s h and something Q - i s h as i t s c o n s t i t u e n t s ; and t h e q u e s t i o n i s what on e a r t h t h e s e P - i s h and Q - i s h t h i n g s m i g h t be:
- n o t t h e p r o p o s i t i o n s P and Q s i n c e , on t h e s o r t o f " n a t u r a l i s t i c " t h e o r y t h a t Loar and I b o t h have i n mind, r e f e r e n c e t o p r o p o s i t i o n s must be e l i m i n a b l e i n t h e l o n g r u n .
- n o t t h e b e l i e f t h a t P and t h e b e l i e f t h a t Q because t h e analogous s o l u t i o n w i l l n o t work f o r t h e c o n s t i t u e n t s o f t h e b e l i e f t h a t P v Q . T h a t i s , s i n c e you can have t h e b e l i e f t h a t P v Q and n o t have e i t h e r t h e b e l i e f t h a t P o r t h e b e l i e f t h a t Q, i t cannot be t h a t t h e l a t t e r b e l i e f s are c o n s t i t u e n t s o f t h e former.
-
- f o r s i m i l a r reasons, i t seems t h a t you cannot c o n s t r u e t h e cons t i t u e n t s o f a b e l i e f as c o n s t i t u e n t s o f i t s f u n c t i o n a l r o l e . Suppose t h a t t h e r e i s a f u n c t i o n a l r o l e C t h e possession o f which i s what i n d i v i d u a t e s t h e b e l i e f t h a t P v Q. I t cannot be ( o r , a t l e a s t , i t cann o t be i n any way t h a t I can make o u t ) t h a t C has as constituents the functional r o l e s associated (respectively) w i t h the b e l i e f t h a t P and t h e b e l i e f t h a t Q. A f t e r a l l , f u n c t i o n a l r o l e s a r e j u s t causal powers, and i t ' s n o t , t o p u t i t m i l d l y , o b v i o u s t h a t t h e r e need be a n y t h i n g t h a t h a v i n g t h e b e l i e f t h a t P v Q causes one t o t h i n k o r do t h a t i s i d e n t i f i a b l y l i k e what h a v i n g t h e b e l i e f t h a t P o r t h e b e l i e f
t h a t Q causes one t o t h i n k o r do. And, even i f t h e r e i s some such i d e n t i f i a b l e causal r o l e c o n s t i t u e n t i n t h e case o f r e l a t i v e l y s i m p l e d i s j u n c t i v e b e l i e f s , t h i n k o f a l l t h e o t h e r ( a l l t h e i n f i n i t e 1 many c o n s t i t u e n t s . Dies one o t h e r ) b e l i e f s t h a t also have P - i s h an-sh r e a l l y want t o u n d e r t a k e t h e burden o f showing t h a t t h e causal r o l e o f , say, t h e b e l i e f t h a t ( i f P t h e n Q ( t h e n i f P t h e n Q o r R ) ) ) has t h e causal r o l e s of P, Q, and R as i t s c o n s t i t u e n t s ? I, f o r one, would n o t know where t o b e g i n . Whereas, i t i s one o f t h e l o v e l y t h i n g s a b o u t t h e language o f t h o u g h t s t o r y t h a t i t g i v e s you t h e c o n s t i t u e n t r e l a t i o n you want f o r free. S p e c i f i c a l l y , i t i s j u s t a c o n d i t i o n upon t h e c o n s t r u c t i o n o f a t y p e / t o k e n r e l a t i o n f o r mental r e p r e s e n t a t i o n s t h a t t o k e n i n g s o f t h e mental symbol t h a t serves as t h e o b j e c t (as i t were) o f t h e b e l i e f t h a t P v Q s h o u l d ( l i t e r a l l y ) c o n t a i n t o k e n i n g s o f whatever mental symbol serves as t h e o b j e c t o f t h e l i e f t h a t P and o f whatever mental symbol serves as t h e o b j e c t o f t h e b e l i e f t h a t Q. J u s t as t o k e n i n s c r i p t i o n s o f t h e f o r m u l a "P v Q" c o n t a i n as l i t e r a l p a r t s t o k e n i n s c r i p t i o n s o f t h e f o r m u l a "P" and o f t h e f o r m u l a "Q". D i g r e s s i o n : you m i g h t suppose t h a t t h e m e n t a l - r e p r e s e n t a t i o n - a s constituent story actually e n t a i l s the causal-role-as-constituent s t o r y , and t h e r e b y i n h e r i t s t h e disadvantages o f t h e l a t t e r . For, y o u m i g h t argue, i f tokens o f t h e mental f o r m u l a s f o r P and f o r Q a r e a c t u a l l y p a r t s o f t h e mental f o r m u l a f o r P v Q, and i f t h e causal r o l e o f a mental s t a t e i s s e n s i t i v e t o t h e c o n s t i t u e n c y o f t h e f o r m u l a t h a t i s tokened when one i s i n t h a t s t a t e (as, indeed, i t must be i f what one contemplates i s some f o r m o f com u t a t i o n a l psychology) t h e n i s i t not g o i n g t o t u r n o u t t h a t t h e cauv Q has t h e causal r o l e o f Q as a c o n s t i t u e n t r e c i s e l y because t h e mental symbol f o r P v Q has t h e mental symbol $ o r Q as a c o n s t i t u e n t ? Answer: o f course n o t . The e f f e c t s o f a mental t o k e n i n g o f P v Q need no more c o n t a i n t h e e f f e c t s o f a mental t o k e n i n g o f P t h a n t h e e f f e c t s o f r e a d i n g t h a t , say, i f i t snows i n August t h e n t h e r e w i l l b e a h e a t wave i n December need i n c l u d e t h e e f f e c t s o f r e a d i n g t h a t i t w i l l snow i n August. I n f a c t , j u s t as i t i s p r e e m i n e n t l y a v i r t u e o f mental r e p r e s e n t a t i o n psychology t h a t i t p e r m i t s us t o c o - o p t t h e l i n g u i s t i c n o t i o n o f cons t i t u e n c y f o r o u r account o f t h e s t r u c t u r e o f mental s t a t e s , so i t i s p r e e m i n e n t l y a v i r t u e o f mental r e p r e s e n t a t i o n t h e o r y t h a t i t a l l o w s us t o c o - o p t l o g i c and computer t h e o r y f o r o u r account o f t h e n a t u r e o f mental rocesses. A f t e r a l l , l o g i c shows us e x a c t l y how t o use t h e syntacDic c o n s t i t u e n c y o f t h e f o r m u l a "P v Q" t o determine t h e e n t a i l m e n t s o f t h e p r o p o s i t i o n t h a t t h a t f o r m u l a expresses. And comp u t e r t h e o r y shows us how t o b u i l d symbol h a n d l i n g mechanisms whose causal processes r e s p e c t , i n a p p r o p r i a t e ways, t h e i n f e r e n t i a l r e l a t i o n s i m p l i c i t i n t h e s y n t a c t i c c o n s t i t u e n c y o f l i n g u i s t i c formulas. Once a g a i n : psychology g e t s a l l t h i s t h e o r y f o r f r e e i f i t once buys t h e mental r e p r e s e n t a t i o n s t o r y .
So what I c l a i m i s t h i s : we need a t h e o r y o f mental s t a t e s ( l i k e be1 i e f s ) and o f mental processes (1 i k e drawing i n f e r e n c e s ) . I t l o o k s as though n o t i o n s o f s t r u c t u r e , and s p e c i f i c a l l y o f c o n s t i t u e n c y , must
be a t t h e h e a r t o f b o t h t h e o r i e s s i n c e , t o p u t i t r o u g h l y , i t i s i n v i r t u e o f t h e i r c o n s t i t u e n c y t h a t (complex) mental s t a t e s have t h e i r semantic p r o p e r t i e s and t h e i r causal r o l e s . The l i n g u i s t i c n o t i o n o f c o n s t i t u e n c y , imp1 i c i t i n t h e p o s t u l a t i o n o f mental symbols, appears t o g i v e us j u s t what we need; i t a l l o w s us t o ground o u r a c c o u n t o f t h e semantics o f mental r e p r e s e n t a t i o n s i n l o g i c and t o ground o u r a c c o u n t o f t h e causal p r o p e r t i e s o f mental r e p r e s e n t a t i o n s i n computer t h e o r y . Moreover, t h e r e a r e l i t e r a l l y no competing accounts. Take away t h e l i n g u i s t i c n o t i o n o f c o n s t i t u e n c y , and we have no i d e a a t a l l o f how b e l i e f s c o u l d have t h e i r i n f e r e n t i a l l i a s o n s o r t h e i r causal roles. Loar m i g h t w i s h t o r e p l y t h a t o n l y t h e u n e l a b o r a t e d causal r o l e s t o r y c o u n t s as " e x p l i c a t i o n " o f b e l i e f , b u t I am n o t s u r e what t h i s amounts t o o r why one s h o u l d c a r e . S u r e l y n e i t h e r t h e o r y p r o v i d e s a n " a n a l y s i s " (as one used t o s a y ) o f t h e " o r d i n a r y n o t i o n " (as one a l s o used t o say) o f b e l i e f . Nor do I r e a l l y t h i n k t h a t h u n t i n g f o r analyses ( i n t h a t , o r maybe any o t h e r , sense) i s a r e a s o n a b l e o c c u p a t i o n f o r grown-ups. What we do want, o r so i t seems t o me, i s My p o i n t has been t h a t j u s t a w o r k a b l e t h e o r y a b o u t what b e l i e f s i f t h e mental r e p r e s e n t a t i o n s t o r y does n o t p r o v i d e t h e t h e o r y , i t i s u n l i k e l y t h a t any o t h e r k i n d o f f u n c t i o n a l i s m w i l l do so e i t h e r .
are.
I w i l l s t o p p r e t t y soon, I promise. B u t f i r s t , l e t me say j u s t a l i t t l e a b o u t some o f t h e p o i n t s LOar makes towards t h e end o f h i s paper a b o u t how t o r u n a t h e o r y o f t h e t r u t h c o n d i t i o n s o f b e l i e f s . As we have seen, t h e n a t u r a l move f o r a r e p r e s e n t a t i o n a l i s t i s t o assume t h a t mental symbols have a l a n g u a g e - l i k e c o n s t i t u e n t s t r u c t u r e and t h e n t o use more o r l e s s f a m i l i a r l o g i c a l d e v i c e s t o e x p l a i n how t h e semantic p r o p e r t i e s o f complex mental symbols a r e i n h e r i t e d f r o m t h e semantic p r o p e r t i e s o f t h e i r a t o m i c c o n s t i t u e n t s . But, n o t o r i o u s l y , that s o r t o f t h e o r y says n o t h i n g a b o u t how mental r e p r e s e n t a t i o n s g e t a t t a c h e d t o t h e w o r l d (how, f o r example, t h e y have ' e x t e r n a l ' t r u t h c o n d i t i o n s as w e l l as ' i n t e r n a l ' causal r o l e s ) and somet h i n g does v e r y much need t o be s a i d a b o u t t h a t q u e s t i o n . There i s a r e c e n t , p r o f o u n d l y unpublished, paper o f mine which s e t s o u t what Loar c a l l s an " i d e a l i n d i c a t i o n t h e o r y " . T h i s i s a l o n g , complicated business, b u t the basic idea i s t h a t t h e t r u t h c o n d i t i o n o f a mental r e p r e s e n t a t i o n i s t h a t s t a t e o f a f f a i r s which would cause a t o k e n i n g o f t h e mental r e p r e s e n t a t i o n under i d e a l c o n d i t i o n s o f t r a n s p a r e n c y o f evidence.
I t h i n k I l i k e t h i s i d e a l a r g e l y because i t seems so v e r y implausi b l e . For example, as Loar p o i n t s o u t , and as I emphasize i n my paper, i t e n t a i l s t h a t any organism t h a t has b e l i e f s a t a l l i s omnis c i e n t under a p p r o p r i a t e i d e a l i z a t i o n . I n f a c t , t o p u t t h e p o i n t more s t r o n g l y , t h e whole i d e a i s b u i l t on t h e i n s i g h t t h a t omniscience i s , as you m i g h t say, t h e t h e o r e t i c a l l y p e r s p i c u o u s c o n d i t i o n f o r a n a c c o u n t o f t h e semantics o f m e n t a l r e p r e s e n t a t i o n s . Consider God. There i s no problem a b o u t what makes a c e r t a i n s t a t e o f a f f a i r s t h e t r u t h c o n d i t i o n o f one o f H i s m e n t a l r e p r e s e n t a t i o n s . Since God b e l i e v e s a l l and o n l y t h e t r u t h s , H i s mental r e p r e s e n t a t i o n s g e t
tokened when, and o n l y when, t h e i r t r u t h c o n d i t i o n s a r e s a t i s f i e d . The t r u t h c o n d i t i o n s o f H i s mental r e p r e s e n t a t i o n s can t h u s be i d e n t i f i e d w i t h whatever s t a t e s o f a f f a i r s a r e c a u s a l l y necessary and s u f f i c i e n t f o r t h e i r tokenings. T h i s may sound p r e t t y s i l l y i n i t s s h o r t v e r s i o n ( a c t u a l l y , i t sounds p r e t t y s i l l y i n i t s l o n g v e r s i o n , t o o ) . But I f i n d i t s o r t o f grows on you a f t e r a w h i l e ; a t a minimum I t h i n k I can show t h a t y o u have t o accept i t i f you a r e g o i n g t o a p p l y t o t h e case o f mental r e p r e s e n t a t i o n t h e s o r t o f " i n f o r m a t i o n a l " semantics t h a t p h i l o s o p h e r s l i k e Stampe and D r e t s k e have r e c e n t l y been f r u i t f u l l y e x p l o r i n g . I w o n ' t , however, t r y t o c o n v i n c e you o f t h i s here. S u f f i c e i t t o say t h a t I do n o t t h i n k t h a t t h e s o r t s o f o b j e c t i o n s Loar r a i s e s f o r t h e program a r e anywhere near d e c i s i v e . F i r s t , Loar says, "The i d e a l i n d i c a t i o n t h e o r y r e q u i r e s t h a t e v e r y i n n e r sentence ... i s i n d i v i d u a l l y s e n s i t i v e t o i t s t r u t h c o n d i t i o n ... But t h i s a p p a r e n t l y c o n f l i c t s w i t h a r a t h e r b a s i c i d e a about t r u t h c o n d i t i o n s , namely, t h a t t h e t r u t h - c o n d i t i o n o f a new sentence i s der i v a t i v e from t h e i n d e e n d e n t l y c o n s t i t u t e d semantic p r o p e r t i e s o f i t s c o n s t i t u e n t s . " ( p . 638P. B u t t h i s i s j u s t wrong i f i t i s supposed t o suggest t h a t t h e f a c t t h a t , f o r example, t h e mental symbol "P 81 Q" has t h e t r u t h c o n d i t i o n s t h a t i t does i s somehow independent o f t h e f a c t t h a t t h e mental symbol "P" has t h e t r u t h c o n d i t i o n t h a t does. On t h e c o n t r a r y , as we have j u s t seen, mental r e p r e s e n t a t i o n t h e o r y appeals t o i n t e r f o r m u l a i c r e l a t i o n s among mental r e p r e s e n t a t i o n s p r e c i s e l y as t h e v e h i c l e f o r p r o j e c t i n g t h e semantics o f i n d e f i n i t e l y many complex b e l i e f s f r o m t h e semantics o f a presumably f i n i t e p r i m i t i v e b a s i s . The b e s t way t o l o o k a t t h i s i s t o t h i n k o f t h e c o g n i t i v e ( i .e., b e l i e f - f i x i n g ) mechanisms o f an organism as a p h y s i c a l r e a l i z a t i o n o f a f u n c t i o n f r o m s t a t e s o f a f f a i r s o n t o mental r e p r e s e n t a t i o n s . Under a p p r o p r i a t e i d e a l i z a t i o n , t h e range and domain o f t h i s f u n c t i o n a r e b o t h i n f i n i t e . I n e f f e c t , t h e system has an i n f i n i t y o f d i s p o s i t i o n a l p r o p e r t i e s o f t h e form: t o k e n t h e mental r e p r e s e n t a t i o n The c o m p u t a t i o n a l s t r u c t u r e of r iff the state o f a f f a i r s ?obtains. t h i s system i s o f p r e c i s e l y t h e s o r t f a m i l i a r f r o m t r u t h d e f i n i t i o n s f o r f o r m a l languages. So t h a t , f o r example, t h e f a c t t h a t t h e d e v i c e tokens "P & Q" i f f i t i s t h e case t h a t P and t h e case t h a t Q i s connected, i n a s t r a i g h t f o r w a r d way, w i t h t h e f a c t t h a t t h e d e v i c e tokens "P" i f f i t i s t h e case t h a t P and tokens "Q" i f f i t i s t h e case t h a t Q. Under t h e o p e r a t i v e i d e a l i z a t i o n , and g i v e n t h e r u l e s f o r "&", t h e causal c o n d i t i o n s f o r t o k e n i n g "P & Q" a r e s a t i s f i e d by, and o n l y by, t h e s a t i s f a c t i o n o f t h e causal c o n d i t i o n s f o r t o k e n i n g "P" and t h e s a t i s f a c t i o n o f t h e causal c o n d i t i o n s f o r t o k e n i n g " Q " . Nothing could be f u r t h e r f r o m t h e i d e a t h a t "every i n n e r sentence i s i n d i v i d u a l l y s e n s i t i v e " t o i t s t r u t h c o n d i t i o n ; and, i n f a c t , I do n o t see how t o make sense o f t h a t i d e a f o r any c o g n i t i v e system o f which t h e r e p r e s e n t a t i o n a l c a p a c i t i e s a r e i n f i n i t e ( a s t h e y s u r e l y a r e f o r us and, I suppose, f o r any d e v i c e w i t h a r e m o t e l y i n t e r e s t i n g mental l i f e ) . L o a r ' s second o b j e c t i o n i s t h a t "some t h e o r i e s t h a t we a c c e p t emerged as hypotheses f r o m t h e i d i o s y n c r a t i c a b i l it i e s . . . o f c r e a t i v e
i n d i v i d u a l s . T h a t t h e r e i s a method t h a t i s t h e n a t u r a l endowment o f each o f us, and t h a t c o u l d have generated t h o s e hypotheses, i s a n i n t e r e s t i n g b u t f a r from obvious t h e s i s . " (p.638). But t h i s o b j e c t i o n i s misled; the ideal i n d i c a t i o n theory i s , i n a c e r t a i n attenuated - o r anyhow i t need n o t be sense, v e r i f i c a t i o n i s t ; b u t i t i s o p e r a t i o n i s t . I t has t o assume, t h a t i s t o say, t h a t e v e r y c o g n i z i n g organism ends toward omniscience i n t h e l i m i t ; t h a t t h e p r o b a b i l i t y t h a t one b e l i e v e s t h a t P becomes a r b i t r a r i l y c l o s e t o u n i t y as t h e evidence t h a t P becomes a r b i t r a r i l y t r a n s p a r e n t . B u t t h i s does n o t e n t a i l t h a t t h e r e must be a n y t h i n g l i k e a method o r procedure f o r d e t e r m i n i n g whether i t i s t h e case t h a t P s i n c e t h e r e i s , i n g e n e r a l , no method o r procedure f o r b r i n g i n g i t about t h a t evidence becomes a r b i t r a r i l y transparent. F i n a l l y , i t seems t o me f a l s e t h a t t h e i d e a l i n d i c a t o r t h e o r y i s incompatible w i t h realism; o r a t least, i f i t i s , the brain-in-a-vat c o n s i d e r a t i o n s do n o t seem t o me t o show t h a t i t i s . What t h e t h e o r y r e q u i r e s , once again, i s omniscience i n t h e e v i d e n t i a l l i m i t ; i n e f f e c t , t h a t i f we a r e b r a i n s i n a v a t , t h e n t h e p r o b a b i l i t y t h a t we w i l l come t o b e l i e v e t h a t we a r e w i l l i n c r e a s e a r b i t r a r i l y as t h e evidence t h a t we a r e b r a i n s i n a v a t g e t s a r b i t r a r i l y b e t t e r . But, o f course, i f t h e b r a i n i n a v a t s t o r y i s a c t u a l l y t r u e o f us now, t h e n t h e e v i d e n t i a l c o n d i t i o n i s e g r e g i o u s l y not s a t i s f i e d . Things l o o k t o us v e r y much as though we a r e n o t b r a i n s i n a v a t b u t r a t h e r c r e a t u r e s i n a w o r l d . I t a k e i t t h a t nobody d e n i e s t h a t t h a t i s t h e s t a t e o f t h e evidence we have, even i f one a c c e p t s t h e l o g i c a l p o s s i b i l i t y t h a t t h e e v i d e n c e we have i s s y s t e m a t i c a l l y m i s l e a d i n g . So now l e t us l o o k a t L o a r ' s argument. Supposing t h a t I am a b r a i n i n a v a t , t h e r e i s , Loar says, "no doubt ...a p o s s i b l e t r u t h t h e o r e t i c i n t e r p r e t a t i o n o f my b e l i e f s which makes them about my sense-data and r e n d e r s them l a r g e l y t r u e on t h a t i n t e r p r e t a t i o n . " (p. 6 4 0 ) . L e t us c a l l t h a t i n t e r p r e t a t i o n Then B r i a n ' s p o i n t i s t h a t s i n c e t h e i d e a l i n d i c a t o r t h e o r y r e q u i r e s us t o a c c e p t t h e i n t e r p r e t a t i o n o f o u r mental s t a t e s t h a t maximizes t h e i r t r u t h o v e r - a l l , t h e n I must be t h e r i g h t i n t e r p r e t a t i o n o f my c u r r e n t b e l i e f s . B u t t h i s i s supposed t o show t h a t t h e i d e a l i n d i c a t o r t h e o r y must be wrong s i n c e , s u r e l y , i f I am a b r a i n i n a v a t , t h e n almost e v e r y t h i n g I now b e l i e v e is
I.
false.
I t s h o u l d now be e v i d e n t w h a t ' s wrong w i t h t h i s ; s i m p l y t h a t t h e i d e a l i n d i c a t i o n t h e o r y does n o t r e q u i r e t h a t t h e r i q h t i n t e r p r e t a t i o n f o r my b e l i e f s i s t h e o n e X i i c f i a x i m i z e s t r u t h h e r e and now. What i t r e q u i r e i s t h a t y o u maximize t r u t h i n t h e e v i d e n t i a l l i m i t . And t h e s a t i s f a c t i o n o f t h i s l a t t e r requirement i s e n t i r e l y compatible w i t h as t h e i n t e r p r e t a t i o n scheme f o r my b e l i e f s even though rejecting i s t h e i n t e r p r e t a t i o n scheme which would maximize t r u t h i f my e v i d e n t i a l s i t u a t i o n were as b e n i g h t e d as t h a t o f a b r a i n i n a v a t . To r e p e a t : t h e i d e a l i n d i c a t o r t h e o r y does n o t say ' p i c k t h e i n t e r p r e t a t i o n scheme t h a t maximizes t r u t h come what may'; what i t says i s o n l y ' p i c k t h e i n t e r p r e t a t i o n scheme which maximizes t r u t h i n c i r c u m stances where t h e t r u t h i s what t h e organism has e v e r y r e a s o n t o
does
I
b e l i e v e ' . I n my view, t h e i r f a i l u r e t o observe t h i s d i s t i n c t i o n has been a s e r i o u s d e f e c t i n p r e v i o u s f o r m u l a t i o n s o f " p r i n c i p l e s o f charity". As f o r t h e more g e n e r a l i s s u e s about t h e r e l a t i o n s between r e a l i s m and t h e i d e a l i n d i c a t o r t h e o r y , t h e y r e q u i r e a l o t more s o r t i n g o u t t h a n I have room f o r here. But r o u g h l y , i f what r e a l i s m r e q u i r e s i s t h a t we understand t r u t h n o n e p i s t e m i c a l l y , as correspondence w i t h states o f a f f a i r s , then t h e i d e a l i n d i c a t o r theory i s thoroughly r e a l i s t i c . The e p i s t e m i c c o n s i d e r a t i o n s come i n , n o t i n s a y i n g what t r u t h i s , b u t o n l y i n d e c i d i n g which s t a t e o f a f f a i r s a mental symbol c o r r e i t i s t r u e ; v i z . , t h a t s t a t e o f a f f a i r s which would sponds t o cause t h e t o k e n i n g o f t h e symbol under c o n d i t i o n s o f i d e a l e v i d e n t i a l transparency .
if
There i s , f o r a l l t h a t , p l e n t y t o w o r r y about w i t h i d e a l i n d i c a t o r t h e o r i e s . For one t h i n g , t h e y a r e a species o f v e r i f i c a t i o n i s m . As such t h e y i m p l y , as B r i a n c o r r e c t l y n o t e s , t h a t t h e r e a r e e p i s t e m i c n o t f a i l t o b e l i e v e t h e t r u e . And circumstances i n which we though t h i s c l a i m i s a t t e n u a t e d i n p r o p o r t i o n as t h e circumstances a r e i d e a l i z e d , I w i l l n o t blame you i f even a t t e n u a t e d v e r i f i c a t i o n i s m i s more t h a n you a r e prepared t o swallow. So perhaps I had b e t t e r c l o s e by emphasizing t h a t t h e need f o r an account o f how mental s t a t e s g e t a t t a c h e d t o t h e i r t r u t h c o n d i t i o n s i s n o t p r o p r i e t a r y t o mental r e p r e s e n t a t i o n c o n s t r u a l s o f p r o p o s i t i o n a l a t t i t u d e s . L e t b e l i e f s and d e s i r e s be c o n s t r u e d as f u n c t i o n a l s t a t e s . SO l o n g as 'causal r o l e s ' a r e r e l a t i o n s t o p r o x i m a l e v e n t s l i k e sensory i n p u t s and motor o u t p u t s , t h e q u e s t i o n must be f a c e d as t o what r e l a t e s p r o p o s i t i o n a l a t t i t u d e s t o d i s t a l events including, notably, t h e s a t i s f a c t i o n o f t h e i r t r u t h c o n d i t i o n s . F u n c t i o n a l i s m does n o t , I r e p e a t , g e t you o u t o f t h i s . The problem i s i m p l i c i t i n any due r e c o g n i t i o n t h a t p r o p o s i t i o n a l a t t i tudes have semantic p r o p e r t i e s l i k e t r u t h and f a l s i t y . So, t o p u t i t b r i e f l y , I would 1 i k e t h e i d e a l i n d i c a t o r s t o r y t o pan o u t i f o n l y because i t i s so whacky. But, i f i t does n o t , a l l o f us m e n t a l i s t s w i l l have t o go h u n t i n g f o r an a l t e r n a t i v e s t o r y ; and we w i l l a l l have t o go h u n t i n g f o r i t t o g e t h e r .
could
Loar, Brian. (1983). "Must B e l i e f s Be S e n t e n c e s ? " I n pSA 1 9 8 7 Volume 2. Edited by P e t e r D. A s q u i t h and Thomas N i c k l e s . East Lansing, Michigan: P h i l o s o p h y o f S c i e n c e A s s o c i a t i o n . Pages 627-643.