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M E T H O D O L O G I C A L SOLIPSISM: A REPLY TO M O R R I S
(Received 3 July, 1984) In my article 'Methodological solipsism' (Philosophical Studies 40, 1981, pp. 269-74) I defended the following two claims: first, that one cannot argue for methodological solipsism by arguing that only opaque psychological states need be mentioned in adequate explanations of intentional action, and secondly, that one cannot argue against (every interesting form of) methodological solipsism by arguing that reference to psychological states in the narrow sense is not sufficient for explanation of intentional action. I also argued that reference to psychological states in the non-wide sense was insufficient for action explanation, and hence that what I called 'weak' methodological solipsism was false. In her article 'In defence of methodological solipsism: A reply to Noonan' (Philosophical Studies 45, 1984, pp. 399-411) Katharine Morris makes some criticisms of my arguments and offers what she calls 'extrinsic' methodological solipsism as a version of the doctrine which is immune to my attack. In what follows I argue that Morris's criticisms are off the mark, and that her version of methodological solipsism is not, or at least is not demonstrated by her to be, any less vulnerable to my arguments than the 'intrinsic' version of the doctrine which I attack. I should add, however, that while I would stilt endorse the first two claims I made in my previous article, I would now wish to argue against my earlier self in respect of the third claim. This is not because I now think any version of methodological solipsism true. I do not. But I think that the argument against it which I gave in my earlier article would, if valid, refute a far more plausible thesis which I would now wish to defend. However, these are wider issues than I shall need to discuss in replying to Morris. In my earlier article I took it for granted that 'narrow' psychological states, as Hilary Putnam and his methodological solipsist opponents understood this notion, had to be ones shared by oneself and one's Doppelg~nger on Twin Earth. 1 One of Morris's criticisms of me is that this is a mistake. Philosophical Studies 48 (1985) 285-290. 0031-8116/85.10 9 1985 by D. Reidel Publishing Company
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Now she is of course right in saying that as defined by Putnam narrow psychological states need not be shared by oneself and one's Doppelg/inger, since they are simply defined as those psychological states which do not presuppose the existence of any individual other than their subject, and selfreferential beliefs such as the belief that one has a headache are plausibly narrow psychological states so defined even though not shared by oneself and one's Doppelg~nger (for the argument for this I refer the reader to my earlier article). But what Morris misses is that the notion of a narrow psychological state needed both by Putnam and by the methodological solipsists for their argumentative purposes is one according to which narrow psychological states are necessarily shared by oneself and one's Doppelg/inger. Morris shows that she has some awareness of this in the case of the methodological solipsists. She writes that, because much of the intuitive appeal of methodological solipsism "derives from the fact that it is supposed to be equivalent to the (prima faeie plausible) assumption that (narrow) psychology supervenes on "what is in the head", i.e. that a person's (narrow) psychological states cannot change or cease to exist unless something alters inside his head", then, even though Earth/Twin Earth concordance is not part of the definition of 'narrow', it had better be entailed by that definition unless the methodological solipsists want to deprive themselves of their best claim to plausibility. Consequently she suggests "[i]t will be to the methodological solipsists advantage to discover the source of difficulty in Putnam's definition, and to revise that definition accordingly". What Morris does not see, however, is that it is as much a difficulty for Putnam as for the methodological solipsists that Earth/Twin Earth concordance is not entailed by his definition of a narrow psychological state. The point is nevertheless easy to appreciate. Putnam's main concern in 'The meaning of "meaning"' is to refute the conjunction of two propositions. One, that the meanings of natural kind terms are determined by what is in the heads of their users, i.e. by their narrow psychological states. And two, that the meanings of natural kind terms determine their extensions. Taken together these two propositions entail that the extension of a natural kind term is determined by its users' narrow psychology, and Putnam attacks the conjunction of the two propositions by attacking this consequence of it. Now Putnam's strategy in his argument is to point out that ~ a t e r ' , as used by me here on Earth, denotes H20 molecules while, as used by my Doppelg~inger on Twin Earth, it may denote XYZ molecules. But this only establishes that
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one's narrow psychology (or that of one's community as a whole) does not fix the extensions of one's natural kind terms on the assumption that I and my Doppelg/inger are narrow psychologically identical. If Putnam's argument is not to fail at its first hurdle, then, he needs a notion of narrow psychology which guarantees this and it is therefore surely most charitable not to hold him to the letter of his definition but to interpret his argument in the light of the notion of narrow psychology which makes most sense of it. But this is not to say that all is well with Putnam's argument if narrow psychology is redefined so as to ensure Earth/Twin Earth concordance on narrow psychological states. For Putnam takes his argument that one's narrow psychology does not fix the extensions of one's natural kind terms to establish also that traditional theorists of meaning were mistaken in their theorizing about natural kind terms in leaving out the 'contribution of the external environment'. However, to establish that this was a mistake Putnam needs to establish that only one's 'wide' psychology - in the sense o f 'wide' psychology he originally defined - fixes the extension of the natural kind terms one employs. But, o f course, this is not established by establishing that one's narrow psychology, redefined to include Earth/Twin Earth concordance, does not do the job, for 'wide' as originally defined is not the contradictory of 'narrow' as redefined to include Earth/Twin Earth concordance. There is, then, a gap in Putnam's arguments corresponding precisely to the category of 'intermediate' psychological states I drew attention to in my original article, i.e. those which are not wide in the sense of Putnam's original definition, but not necessarily shared by oneself and one's Doppelg~nger. But Morris would, I believe, reply to all this (though not, of course, on behalf of Putnam, since she herself is a methodological solipsist) that I am nevertheless still in the wrong in discerning a category o f intermediate psychological states which are neither wide nor narrow. For granted that I was not simply mistaken in assuming that Earth and Twin Earth concordance had to be part of Putnam's notion of a narrow psychological state it remains that it is an error to assume that no definition of narrow psychology which entails the narrow psychological identity of oneself and one's Doppelg~nger can fail to exclude self-referential beliefs from the category of narrow psychological state. In fact one can achieve a definition of narrow psychology which ensures Earth/Twin Earth concordance in narrow psychology and allows self-referential beliefs to count as narrow by a very simple change in Putnam's original definition: namely be defining a narrow psychological state
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as one which does not presuppose the existence o f anything at all - not even that of its subject ('In defense o f methodological solipsism', p. 405). I am afraid, however, that I do not understand this suggestion. It seems straightforward to draw a distinction between those states such that, if an individual is in one of them then some other individual must exist, and those states of which this is not true. But all psychological states are such that if an individual is in such a state then he exists. If I am jealous of John then both I and John must exist, but perhaps I could be in pain even if nothing else existed apart from myself (and maybe my body). However, I could not be in pain unless I existed. I take it that it was a consciousness of these truisms which made Putnam define narrow psychology in the way to which Morris objects. In defence of her revision of Putnam's definition Morris draws attention to Gareth Evans' suggestion in The Varieties o f Reference (Oxford, 1982) that (purported) 'F-thoughts can fail to refer in much the same way as other demonstrative or indexical thoughts can fail to refer. In fact Evans' suggestion is highly contentious and however one takes it it seems to involve grave difficulties. But a discussion of these would be beside the point, for it is fairly obvious, I think, that even if Evans' suggestion is correct it is incapable of providing any support for Morris's position. For Evans' suggestion is merely that a thinking subject is not guaranteed to secure h i m s e l f a reference just by thinking 'I'. But what Morris requires to be true is some such proposition as that a thinking subject is not guaranteed to exist just by thinking 'I', which is another matter altogether. So much then for Morris's first criticism. Her second is that I have ignored a version of methodological solipsism which is far more plausible than any I consider, which she calls 'extrinsic ~methodological solipsism. Morris explains her distinction between 'intrinsic' and 'extrinsic' methodological solipsism as follows. Intrinsic methodological solipsism says that there are two distinct classes of mental states, viz. narrow ones and wide ones and that the latter are redundant in the explanation o f intentional action. By contrast the extrinsic methodological solipsist says that there are merely two manners o f attributing mental states, viz. narrowly and widely. On this interpretation, there is no class of mental states which is beyond the reach of the methodological solipsist; there is simply a way of attributing which he, qua methodological solipsist, is not entitled to use. If I understand this what it amounts to is the claim that there are no wide
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psychological states, i.e. no psychological states which are essentially 'relational' or 'world involving' (see 'In defense of methodological solipsism', p. 400), for a state could hardly be attributed narrowly if it was essentially 'world involving'. According to extrinsic methodological solipsism then even the beliefs we express with demonstratives and indexicals, e.g. the belief that 'that flower vase is pink', do not require for their existence the existence of the objects they are in fact about. It is the denial of this that Morris refers to as 'the intuition about content'. And rightly, I think, she believes that the failure o f many people even to consider extrinsic methodological solipsism is to be explained by their adherence to it. However, that is not the case with me. In fact I reject the intuition about content and would agree that extrinsic methodological solipsism is a more plausible position than intrinsic methodological solipsism; for unlike the latter it does not entail the existence of a category of psychological states which are redundant in the explanation o f action (in fact, I believe, the distinction between intrinsic and extrinsic methodological solipsism corresponds to the distinction I drew in my article between weak and moderate solipsism). But extrinsic methodological solipsism is committed just as much as intrinsic methodological solipsism to the view that only narrow psychological states need be referred to in action explanation - since it entails that there are only narrow psychological states - and for this reason it is quite mistaken to think that it could be more easily defended against my arguments than the latter. Morris's defence of extrinsic methodological solipsism in the end rests on the claim that 'explanations of actions in terms o f wide mental states cut actions and mental states so finely that the notion o f "explanation" hardly seems in order'. If I and m y Doppelg~/nger each perform an action whose intentional description we would each give as 'trying to kick that cat', and each of us would give as his reason a statement of the form 'I tried to kick that cat because I believed it was the one that bit me last week', then, Morris suggests, in the only sense relevant to psychological explanation, we have done the same thing. If so, o f course, then reference to any wide psychological states we may have is bound to be redundant in the explanation o f our action, since we must differ in our wide psychological states. But I do not see why this reply to my argument should be less cogent in the mouth of the intrinsic methodological solipsist than in that of the extrinsic methodological solipsist. Indeed, I do not see why, if cogent at all, it should not be equally cogent as a defence of strong methodological solipsism as I originally defined
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it. However, in fact it is not cogent, for the fact is that we do allow that actions are psychologically explicable under descriptions containing singular terms denoting objects in their agent's environment, and so described my actions are distinct from my Doppelg~nger's. The point is actually a familiar one, made both by Gareth Evans in The Roots of Reference, p. 203 and by Christopher Peacocke in 'Demostrative thought and psychological explanation' (Synthese 49, 1981). Nevertheless it suffices to expose the inadequacy in Morris's defence of extrinsic methodological solipsism.
NOTE 1 The notion of a narrow psychological state is introduced by Putnam in 'The meaning of '~meaning" in his Philosophical Papers, Vol. 2 (Cambridge University Press, 1975). It is employed by J . A . Fodor in his 'Methodological solipsism considered as a research strategy in cognitive psychology' (Behavioural and Brain Sciences 3, 1980, pp. 63-72).
Department of Philosophy, The University of Birmingham, P.O. Box 363, Birmingham, B15 2TT, U.K.
