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it is shaped, sir, like itself, and it is as broad as it hath breadth; it is just so high as it is, and moves with its own organs; it lives by that which nourisheth it; and the elements once out of it, it transmigrates. (Shakes- peare: Antony and Cleopatra)

Professor P u t n a m has recen t ly a rgued ~ that if there were bra ins in vats , wha t they would be saying when they said that they were bra ins in va t s would be false, and so tha t there were brains in va t s would imply its own falsity, and so be false ( ( p - - ~ - p ) - - > - p ) .

In a r ecen t art icle in E rkenn tn i s 2 I a rgued that , e v e n if wha t a brain in a va t would be saying w h e n (he, she or) it said tha t it was a bra in in a va t were false (which it would not necessar i ly be) this would not show tha t it was bo th t rue and false that it was a bra in in a vat . Th is is because , if the p ropos i t ion tha t a bra in in a va t is asser t ing when it says tha t it is a b ra in in a va t is the p ropos i t ion tha t it is an image bra in in an i m a g e vat , this p ropos i t ion is not the con t r ad ic to ry of the p ro - pos i t ion I a m asser t ing when I say tha t it is a bra in in a vat . T h e r e is t he re fo re not one propos i t ion , asser ted bo th by me and by a brain in a vat , which is such as to be false if it is true.

P u t n a m ' s mis take arises f r o m confus ing a bra in in a va t ' s u t te r ing the s en t ence ' I a m a brain in a va t ' with its asser t ing the posi t ion that it is a bra in in a vat . It would not be asser t ing this propos i t ion , if P u t n a m is r ight in th inking that by ' b ra in ' it m e a n t ' i m a g e bra in ' and by ' va t ' it m e a n t ' i m a g e va t ' .

P ro fessor K r i p k e has ma in ta ined 3 tha t there is a class of con t ingen t p ropos i t ions tha t m a y be k n o w n a priori . For example , the m e t r e rod in Paris m igh t h a v e b e e n shor te r than it is. H e n c e tha t the m e t r e rod in Paris is a m e t r e long is a con t i ngen t propos i t ion . W e know a pr ior i tha t it is a m e t r e long, h o w e v e r , because the word ' m e t r e ' is a n a m e for tha t l eng th which, it so happens , is the length of the m e t r e rod in Paris.

I ag ree with K r i p k e tha t the m e t r e rod in Paris m igh t have been shor te r than it is. If the hand of the c r a f t s m a n who m a d e it had s l ipped, as it m igh t h a v e done , then it p r o b a b l y would have been less than a m e t r e long. I do not ag ree wi th Kr ipke , howeve r , tha t we know a pr ior i tha t it is a m e t r e long.

Erkennmis 27 (1987) 283-290. �9 1987 by D. Reidel Publishing Company

284 J O N A T H A N H A R R I S O N

Since the metre rod in Paris is 39.37 inches, the word 'me t re ' is a name for a length which is 39.37 inches. We cannot know a priori that the metre rod in Paris is 39.37 inches. Hence we cannot know a priori what length, measured in inches, the word 'me t re ' names. What I have just said is true of any other unit of measurement one cares to think of, e.g., ells.

If the metre rod is (as it is) 39.37 inches long, 'me t re ' will be a name for a length which is 39.37 inches. If, as might have been the case, the metre rod was 40 inches long, 'me t re ' would be a name for a length which was 40 inches. In either event, if we were to say that the metre rod in Paris was a metre long, we would have to be saying what was true. But what we would be saying in the two cases would be different. In the first case (because 'me t re ' would refer to a length which was 39.37 inches) we would be saying that the metre was a length which was in fact ( though we would not be saying this) 39.37 inches. In the second case, we would be saying that it was a length which was in fact 40 inches. (There would not be one statement, expressed in the words 'The metre rod in Paris is 39.37 inches long' , but two.

We would not know either of these s tatements a priori, for it is just an empirical fact that the metre rod in Paris is a length which is 39.37 inches, and it would be just an empirical fact that it was 40 inches, if it were 40 inehes. Hence what we are saying, when we say that the metre rod is a metre long in the event of the metre being 39.37 inches long, is an empirical discovery, and what we would be saying, if we said that the metre rod was a metre long in the event of the metre ' s being 40 inches long, would also be an empirical discovery.

A similar example is this. A tribe might introduce the numeral ' umpteen ' into their language as a name for that number which is the number of grains of rice in their medicine man ' s bowl. If there were 1003 grains of rice in the bowl, ' umpteen ' would be a word for the number 1003, and what they say when they say that there are umpteen grains of rice in the bowl will be true. If there are 1083 grains of rice in the bowl, ' umpteen ' will be a word for 1083, but it will still be true to say that there are umpteen grains of rice in the bowl. But the propositions they were using the sentence 'There are umpteen grains of rice in the medicine man ' s bowl' to assert will be different. If there are 1003 grains of rice in the bowl, anyone uttering the sentence 'There are umpteen grains of rice in the bowl' will be asserting that there are 1003 grains of rice in the bowl. If there are 1083 grains of

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rice in the bowl, anyone uttering the sentence 'There are umpteen grains of rice in the bowl' will be asserting the proposit ion that there are 1083 grains of rice in the bowl. Neither of these will be a priori propositions.

Because of the way the word ' umpteen ' is introduced into their language, their sentence 'There are umpteen grains of rice in the bowl' can be known a priori to express a true proposition. But it does not follow from this that they can know a priori that the proposit ion it does express is true.

If we turn from a priority to necessity, we must distinguish between saying that a sentence expresses a necessary truth (( 's ' expresses p ) . Lp), and saying that it necessarily expresses a truth (L(( ' s ' expresses p)~--~p)). The proposit ion that the sentence "There are umpteen grains of rice in the bowl' necessarily expresses a truth, will be true. The truth this sentence does express, however, will not be necessarily true.

Similarly, let us suppose that, having four children, I decide to call my fifth child 'T racey ' , and, when it arrives, do so. 4 It does not follow that I know a priori the truth of the proposit ion that I now express when I say 'T racey is my fifth child'. For, if Tracey, who is in fact a boy, were a girl, the word 'T racey ' would have named a different child from the child this word does name. Then, though what I would be saying (the proposit ion I would be asserting) would still be true, it would not be the same proposit ion that I am asserting, given that Tracey is a girl.

A parallel case may help still more to make this clear. If I say 'I am here ' , I am bound to be expressing a truth. But it is just a contingent fact, known empirically, that I am here in my depar tment and not somewhere else (e.g., at home). If I were at home, however , the sentence ' l am here ' would still express a truth, but a different truth (the truth that I am here at home). It is an interesting fact about the sentence 'I am here ' that wherever I am, it must express a truth. It does not follow from this, however, that it ever expresses a necessary truth, for none of the truths it does express, e.g., that I am here in my depar tment , that I am here at home, and so on, are necessary truths. It is important to distinguish the s ta tement that a sentence must express a truth f rom the s ta tement that a sentence expresses a necessary truth. It is confusing that in the English language either s ta tement can be put in exactly the same words.

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Putnam, when he claims 5 that it is a logical truth that 'cows ' is the word for cows, is also confusing a sentence that expresses a necessary truth with a sentence that necessarily expresses a truth. Since cows did not have to be called 'cows' , but might have been called ' sheep ' , it is not a logical truth that this is what cows are called. But if ' cows ' did mean sheep, the sentence ' " C o w s " is a word for cows' would still express a truth, but a truth about sheep, and not the truth about cows that it now expresses.

Again, it is not a logical truth that Henry is called 'Henry ' . If he had been a girl, he might have been called 'Henr ie t ta ' , and not 'Henry ' . If he had been called 'Henr ie t ta ' , then we could not use the sentence 'Henry is not called " H e n r y " , but " H e n r i e t t a " ' to express this fact. If Henry had been called 'Henr ie t ta ' , we could not use the word 'Henry" to refer to him: but we need to be able to do this in order to use this sentence to say that his name is not 'Henry ' . Hence anyone using the sentence 'Henry is not called " H e n r y " ' is at tempting to do something which it would be impossible to do if what he said were true. What he asserted would not be contradictory, but there is a pragmat ic in- consistency inw)lved in his uttering it, because he would not be able to succeed in what he is a t tempting to do if the proposit ion that he were at tempting to assert were true.

It looks as if it follows from this that there is a class of possibilities which could not be truly asserted to be realised if they were realised. (All that may in fact follow, however, is that they could not be asserted to be realised in the words in which the fact that they were possibilities was originally expressed.) For example, though it is pos- sible that I might not have been here, if I had not been here, I could not have asserted the realisation of this possibility in the words ' I am not here' .

It would also follow that there is ~ class of unfulfilled conditional propositions, for example, the proposition that if Henry was not called 'Henry ' , Henry would have been called 'Henr ie t ta ' , whose antecedents could not be truly asserted if they were fulfilled. And though it may be true that, if I were not here, I would be happier than I am, it is not possible for me truly to say 'I am not here, and I am happier than I am' . The possibility of 'cows ' not meaning cows belongs to this class. Though cows might perfectly well not have been called 'cows' , anyone saying 'Cows are not called " c o w s " ' cannot be saying what is true.

Another sentence of the type we are considering is ' "Bru tus killed

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Caesar" means that Brutus killed Caesar ' . 'Brutus killed Caesar ' does not have to mean that Brutus killed Caesar , and would have meant something else if 'killed' had meant begat. But, if 'killed' had meant begat, anyone saying ' "B ru t u s killed Caesa r" does not mean that Brutus killed Caesar ' would have been asserting the proposit ion (which would then be false) that 'Brutus killed Caesar ' did not mean that Brutus begat Caesar. The sentence ' "Bru tus killed Ceasar" means that Brutus killed Caesar ' is just another sentence that neces- sarily expresses a truth (as opposed to expressing a necessary truth).

Probably the most important possibility of this kind is the possibility that the sentence 'Snow is white' should be false, while snow remained white. ~ It is a mistake to think that it is impossible for 'Snow is white ' to be false (or, as I would prefer to say, express a falsehood) in English while snow was white. It is, indeed, rather obvious that this is possible, f o r changing the meaning of the word 'white ' could hardly affect the whiteness of snow. So the sentence 'Snow is white' would be (or express what is) false, though snow was white, if 'white ' meant black. But, though it is perfectly possible for 'Snow is white' to be false (or to express what is false) while snow remained white, if this possibility were realised, it could not be said to be realised in the words in which the original possibility was expressed. For, if ~white" were to mean black anyone saying ' " S n o w is white" is (or expresses what is) false, al though snow is white ' , would not be expressing this possibility. For, if 'white ' did mean black, anyone uttering the sentence 'Snow is white ' , would be using this sentence not to say that snow was white, but to s~y that snow was black.

The sentence ' " S n o w is white" is true if and only if snow is white ' , therefore, though it is customary to say that it is a trivial truth, is not a sentence that expresses a necessary truth at all. If "white" meant black, the sentence ' " S n o w is white" if and only if snow is white' would still express a truth, but the truth that would be expressed, if "Snow is white' were to be the way of asserting that snow is black, would be a different truth from that which is now expressed in those words.

It follows that, though it is possible to say such things as 'Once upon a t ime "cows" did not mean cows', and 'There will be a time in the future when "cows" no longer means cows' and 'There is a language other than English in which 'cows" does not mean cows', and ' I t is possible for "cows" not to mean cows', and 'If "cows" did not mean cows, the English would probably have had another word for them' , it

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is not possible to say, in English, such things as ' " C o w s " does not mean cows'. This, again, is because if 'cows ' did not mean cows, it would be impossible to use the word 'cows ' to refer to cows, in order to say that they were not called 'cows' .

It also follows that, though I have not always been here, and a time will come when I am not here, and though it is perfectly possible for me not to be here, and it is possible to assert unfulfilled conditional propositions whose antecedents are expressed in the words ' If I were not here ' , if 1 say ' I am not here' , I must be using this sentence to express a proposit ion that is false.

Again, 'Snow is white ' has not been (or expressed what is) true nearly as long as snow has been white, and snow will be white for much longer than the sentence 'Snow is white' will be true, and it is perfectly possible for the sentence 'Snow is white ' to be false, without snow's ceasing to be white. It is possible for remarks such as ' I f "Snow is white" were false, while snow remained white, this must be either because "Snow" does not mean snow or "whi te" does not mean white ' , to be (or express what is) true. It is not possible, however , for the remark, made in the present tense, ' " S n o w is white" is true, but snow is not white ' to be (or express) what is true.

An interesting example of the same kind of impossiblity 7 is that 'plus ' should not mean plus, but quus. Though 'plus ' might have meant quus, if it had meant quus anyone saying ' " P l u s " means quus' would have been saying what is false (at any rate, if you assume that if 'plus ' had meant quus, then 'quus ' would not also have meant quus). If you have to use the word 'quus ' to refer to what 'plus ' means, it follows that 'plus ' cannot mean it. One is again trying to do something that would not be possible if what one were trying to assert were true. The sentence ' " p l u s " means plus' is as much a sentence that necessarily expresses a truth as the sentence ' " C o w s " means cows'. ( ' "P lus" means quus' is as much a sentence that necessarily expresses a falsehood as is the sentence ' " C o w s " means sheep').

It follows f rom this that, though one might consider the possibility of 'plus ' not meaning plus, and think that once upon a t ime 'plus ' did not mean plus, and that in the future 'plus ' might not mean plus, and that 'plus ' might nol~ mean plus to other people, and consider the truth of hypothetical proposit ions about what might be the case if 'plus ' did mean plus, one cannot consider the possibility that 'plus ' does not mean plus, to me, now.

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T o do this would be like cons ider ing that pe rhaps ' cows ' does not m e a n cows, or that pe rhaps I am not here. Since the sen tence ' I am here ' necessar i ly expresses a con t ingen t t ruth, it is qui te inappropr i a t e to say that pe rhaps I am not here. (Saying ' Pe rhaps I am not he re ' is not at all to say that I migh t not have been here , which is a sensible thing to say. For it is app rop r i a t e to say ' P e r h a p s p ' of a necessary t ruth (e.g., ' P e r h a p s there is some even n u m b e r which is not the sum of two pr imes ' ) , and inappropr i a t e to say it of a con t ingen t t ruth which there is no real reason to doubt . A n d there can be no real reason to doub t that I am here, for we use the sen tence ' l am here ' so that it c anno t be that it expresses anyth ing that is false.)

W h e n I say ' T h e me t r e rod in Paris is a me t re long ' , I am also using a s en t ence that necessar i ly expresses a t ruth, not a sen tence that expresses a necessary truth. If ' m e t r e ' is in t roduced into the l anguage as a name for that length which, it so happens , the me t r e rod in Paris has, then, w h a t e v e r length that is, that length is the length that I am saying it is, just as, if ' h e r e ' is a n a m e for the p lace I am, w h a t e v e r the p lace I am when I say ' I am here ' , that is the p lace at which I am saying that I am. 1 am not, howeve r , saying the same thing (asser t ing the same proposi t ion) , when I use the sen tence "The me t re rod is a me t r e long ' h o w e v e r long the me t r e rod is. For, if the rod is one length, I am refer r ing to that length and saying the rod is that length, and, if it is ano the r length, I am refer r ing that that o the r length, and saying tha t it is that o the r length.

It will also follow that the s t a t e m e n t that the me t r e rod in Paris is a me t r e long will r e semble the s t a t emen t s that H e n r y is cal led ' H e n r y ' , that ' cows ' m e a n s cows, that 'p lus ' m e a n s plus, that 'Snow is whi te ' m e a n s that snow is white, and that ' " S n o w is wh i t e " is t rue if and only if snow is whi te ' in that (1) it c anno t be sensible to say such a thing as ' Pe rhaps the me t r e rod in Paris is not a me t r e long ' ; in that (2) there would be a p r a g m a t i c con t rad ic t ion in asser t ing that the me t re rod in Paris was not a m e t e r long and in that (3) t hough we can en ter ta in the possibil i ty (which is a genu ine one) of the me t r e rod in Paris ' s not be ing a m e t r e long, we could not say that this possibil i ty was real ised, if it were real ised, or not, at any rate , in the words ' T h e m e t r e rod in Paris is not a me t r e long ' . Th is is due to the fact that (4) the sen tence ' T h e m e t r e rod in Paris is a me t r e long ' is a s en t ence that necessar i ly expresses some con t ingen t truth.

1 suspec t that the reason why Kr ipke thinks that he has p r o d u c e d

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an e x a m p l e of a c o n t i n g e n t p r o p o s i t i o n tha t is k n o w n a p r io r i is

tha t , by i g n o r i n g the last of t h e s e f o u r d i s t i n c t i o n s he has c o n f l a t e d two

p r o p o s i t i o n s . (i) T h e r e is t h e c a t e g o r i c a l p r o p o s i t i o n e x p r e s s e d by the

s e n t e n c e ' T h e m e t r e r o d in Par is is a m e t r e l o n g ' . T h i s p r o p o s i t i o n is

c o n t i n g e n t , b u t is k n o w n to be t r u e a p o s t e r i o r i . (ii) T h e r e is the

h y p o t h e t i c a l p r o p o s i t i o n tha t if any p r o p o s i t i o n is tha t w h i c h is

e x p r e s s e d by the s e n t e n c e ' T h e m e t r e r o d in Par is is a m e t r e l o n g ' it

m u s t ( a s s u m i n g , of c o u r s e , t h a t the E n g l i s h l a n g u a g e is b e i n g u s e d

c o r r e c t l y ) be a t rue p r o p o s i t i o n . T h i s p r o p o s i t i o n is k n o w n a p r io r i , bu t

it is a n e c e s s a r i l y t rue p r o p o s i t i o n , no t a c o n t i n g e n t o n e .

N O T E S

J In Reason, Truth and History, Cambridge University Press, 1981, especially p. 14f. In 'Professor Putnam on Brains in Vats', Erkenntnis (1985) pp. 55-57.

�9 In Naming and Necessity, Basil Blackwell, Oxford, 1980, especially p. 54 f. 4 See 'Dthat', by David Kaplan, in Contemporary Perspectives in the Philosophy of Language, edited by Peter A. French, Theodore E. Uehling, Jr., Howard K. Wettstein, University of Minnesota Press, Minneapolis, 1979. -~ In 'Meaning and the Moral Sciences', Routledge and Kegan Paul, 1978, page 136).

See 'The Concept of Truth in Formalised Languages', in Logic, Semantics and Metamathematics, Oxford University Press, 1956. 7 Discussed by Kripke in Wittgenstein on Rules and Private Language, Blackwell, 1982. x It has been drawn to my attention that a similar criticism of Kripke's argument has been made by Professor Keith Donellan in his article ('The Contingent A Priori and Rigid Designator's, also in Contemporary Perspectives in the Philosophy of Language). There he expresses the view that sentences like 'The metre rod in Paris" are stipulatively defined as being true, from which he thinks it follows that what they assert must be true. I have difficulty in seeing how you can stipulate that a sentence shall express a truth. My own view is that it is because of the way in which some words (such as 'this' or 'means') are used that some sentences containing that word come necessarily to express a truth, and that it as a result of such a definition of 'metre' that the sentence 'The metrc rod in Paris is a metre long' must necessarily express a truth.

It has also been drawn to my attention that a not dissimilar argument against Frege has been put forward by Professor Michael Dummett in Frege: Philosophy of Language, Duckworth, second edition 198 l, especially p. 120f.

Manuscript received 9 April 1986

Dept of Philosophy The University of Notthingham GB-Nottingham NG7 2RD England