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Putnam's Brain-Teaser

Published online by Cambridge University Press:  01 January 2020

David Davies
David Davies*
Affiliation:
McGill UniversityMontreal, PQCanadaH3A 2T7
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Extract

1. Metaphysical Realists have traditionally relied upon the skeptic to give substance to the idea that truth is, in the words of Hilary Putnam, 'radically non-episternic,’ forever outstripping, in principle at least, the reach of justification. What better model of truth so conceived, after all, than the skeptic's contention that even our firmest convictions might be mistaken in that we might be the victims of demonic deception or the machinations of an evil scientist? But the availability of this favorite model of Realist truth, encapsulated in the claim that we might be ‘brains in a vat,’ has been called into question by Putnam in the opening chapter of Reason, Truth, and History. Putnam contends that, if we grant the Realist notion of truth, as referentially mediated correspondence to THE WORLD, then, given certain plausible constraints on reference, we can know that we are not brains in a vat (or, more accurately, ‘brains in a vat' of a particular kind, as we shall see).

Type
Research Article
Information
Canadian Journal of Philosophy , Volume 25 , Issue 2 , June 1995 , pp. 203 - 227
Copyright
Copyright © The Authors 1995

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References

1 Cambridge: Cambridge University Press 1981. Henceforth RTH.

2 ‘Brains in a Vat,’ Journal of Philosophy 83 (1986) 148-67

3 Even these features have been misconstrued by certain of Putnam's critics. Perhaps the most flagrant example is Harrison, Jonathan ‘Professor Putnam on Brains in Vats,’ Erkenntnis 23 (1985) 55-8CrossRefGoogle Scholar, whose dismissive discussion rests not only upon a violation of the ‘terms of envatment’ (see below) but also upon a construal of the problematic utterance as a third-person claim ('s is a brain in a vat’), rather than a first-person claim.

4 E.g., Goldman, A.H. ‘Fanciful Arguments for Realism,’ Mind 93 (1984) 19–38CrossRefGoogle Scholar and Lewis, D. ‘Putnam's Paradox,’ Australasian Journal of Philosophy 62 (1984) 221-36.CrossRefGoogle Scholar

5 I owe this example to John Collier.

6 Smith, P. ‘Could We Be Brains in a Vat?’ Canadian Journal of Philosophy 14 (1984) 115-23CrossRefGoogle Scholar

7 Languages of Art (Indianapolis: Bobbs-Merrill 1968)

8 For example, McIntyre, J. ‘Putnam's Brains,’ Analysis 44 (1984) 59–61CrossRefGoogle Scholar, identifies and rejects two possible formulations of the argument suggested by certain of Putnam's remarks. Iseminger, G. ‘Putnam's Miraculous Argument,’ Analysis 48 (1988) 190-5CrossRefGoogle Scholar, makes effectively the same points.

9 See also Williams, M. Review of Reason, Truth, and History, Journal of Philosophy 81 (1984) 257-61.Google Scholar

10 In spite of the arguments of McIntyre and Iseminger, one still finds philosophers defending this second version of the BIV argument. See, for example, Dell'Utri, M. ‘Choosing Conceptions of Realism: The Case of the Brains in a Vat,’ Mind 99 (1990) 79–90, at 87.CrossRefGoogle Scholar

11 See ‘The Meaning of “Meaning,“’ reprinted in Mind, Language, and Reality: Philosophical Papers Volume II (Cambridge: Cambridge University Press 1975) 215-71.

12 Brueckner correctly identifies the feature in question — the pragmatically self-refuting nature of the sentence ‘I am a BIV'— but misses its significance in invalidating, for the L-conditionals employed in B1-B7, the general principle for assessing indicative L-conditionals. He also fails to address the sorts of constraints needed to single out the appropriate class of languages in which the sentence ‘I am a BIV’ is pragmatically self-refuting.

13 This is not to say that Putnam does not, in places, represent what he is doing in the ways seized upon by his critics, but it is to suggest that a careful and charitable reading will permit us to distinguish those passages in which Putnam misrepresents his argument from those passages in which he represents it correctly.

14 Putnam avails himself of Dennett's, (‘Beyond Belief,’ in Woodfield, A. ed., Thought and Object [Oxford: Clarendon 1982] 1–96)Google Scholar locution ‘notional world’ in chapter 2 of RTH. Adopting from Husserl the concept of a ‘bracketed’ belief, where bracketing 'subtracts … from the ordinary belief locution … all the entailments that refer to the external world, or to what is external to the thinker's mind,’ he characterizes a thinker's ‘notional world’ as ‘the totality of a thinker's bracketed beliefs.’ He also notes that there is identity, or virtual identity, in notional worlds in both the Earth/Twin Earth and the BIV /non-BIV cases (RTH, 28-9).

15 See, Kripke, S. Naming and Necessity 2nd ed. (Oxford: Basil Blackwell 1980)Google Scholar for an account of a period contingent truth, and Putnam's ‘The Meaning of “Meaning” for a discussion of the indexical component in reference.

16 See, for example, Tichy, P. ‘Putnam on Brains in a Vat,’ Philosophia 16 (1986) 137-46CrossRefGoogle Scholar, for a painstaking demonstration that Putnam fails to show that the BIV hypothesis is metaphysically impossible. Tichy eventually acknowledges that this might not be what Putnam has in mind, and then claims that, if so, then ‘Putnam's use of the term “possible” is very unorthodox indeed. According to an almost universal consensus, to say that something is possible is to make an existential claim about possible worlds, not a claim about a particular world’ (142). This applies to metaphysical possibility, but not to epistemic possibility. See also Malachowski, A. ‘Metaphysical Realist Semantics: Some Moral Desiderata,’ Philosophia 16 (1986) 167-74CrossRefGoogle Scholar: ‘The metaphysical realist will naturally balk at the following kind of claim: “The existence of a ‘physically possible world’ in which we are brains in a vat (and always were and always will be) does not mean that we might really actually, possibly be brains in a vat. What rules out this possibility is not physics but philosophy” (Reason, Truth, and History, p. 15). If “The existence of a ‘physically possible world’ in which we are brains in a vat” does not mean that we might actually be brains in a vat, what does it mean?’ (174); and Kinghan, M. ‘The External World Sceptic Escapes Again,’ Philosophia 16 (1986) 161-6CrossRefGoogle Scholar, who states that ‘Putnam undertakes to show that there is no logically possible world in which we are all brains in a vat’ (161).

17 It might also be thought that the inference in 3d is open to the same objections that I brought against Brueckner's formulation. For 3d relies upon an implicit premiss —an instantiation of the generalization implicit in the conclusion of 3c—that takes the form of an L-conditional: specifically, ‘If I am speaking a language L, then my utterance of the sentence ‘I am a BIV’ is pragmatically self-refuting.’ But this L-conditional is true when assessed against the general principle for indicative L-conditionals —there is, here, no departure from this principle, and therefore no need to account for such a departure.

18 See Kaplan, D. ‘Demonstratives, Draft #2’ (unpublished ms, 1977).Google Scholar

19 Searle, J. ‘Minds, Brains, and Programs,’ The Behavioral and Brain Sciences 3 (1980) 417-24CrossRefGoogle Scholar

20 Davidson, reaches a similar conclusion in his paper ‘What Is Present To The Mind?’ in Brandl, J. and Gombecz, W. eds., The Mind of Donald Davidson (Amsterdam: Rodopi 1989),Google Scholar maintaining that ‘it does not make sense to suppose that I am generally mistaken about what my words mean; the presumption that I am not generally mistaken about what I mean is essential to my having a language— to my being interpretable at all.’ If we bear in mind that, for Davidson, intentional ascriptions make sense only in the context of interpretation, which, in turn, is governed by the requirement that we make sense of the agent's verbal and non-verbal behavior in a shared environment, then the Davidsonian point bears comparison with the claim, in the text, that intentional ascriptions are closely tied to the manifest linguistic abilities of agents.

21 As a further ‘intuition pump’ on these matters, consider how we treat more conventional cases of ‘pragmatically self-refuting’ sentences —for example, ‘I am not here now,’ uttered under standard conditions. A speaker can surely know that, in uttering this sentence, she expresses a falsehood, and can know what falsehood she expresses, without having to know the specific reference of the indexicals on the occasion of utterance. A speaker who is, for some reason, unsure as to her precise spatio-temporal location, is not thereby deprived of an understanding of what she is asserting when she utters the sentence ‘I am here now.’

22 See, for example, Feldman, S. ‘Refutation of Dogmatism: Putnam's Brains in Vats,’ Southern Journal of Philosophy 22 (1984) 323-9CrossRefGoogle Scholar; Stephens, J. and Russow, L. ‘Brains in Vats and the Intemalist Perspective,’ Australasian Journal of Philosophy 63 (1985) 205-12CrossRefGoogle Scholar; and Kinghan.

23 See RTH 6, where Putnam explicitly distances his discussion of the BIV hypothesis from issues of skepticism.

24 See Goodman, N. Ways of Worldmaking (Indianapolis: Hackett 1978).Google Scholar

25 I should like to thank all who have contributed to the writing of this paper through discussion and comments on earlier drafts. In particular, I should like to thank Philip Catton and William Harper for assistance in the initial stages of my research, John Collier, Michael Hallett, and a referee for Canadian Journal of Philosophy. Some of the work on this paper was supported by a Research Fellowship from the Social Sciences and Humanities Research Council of Canada, whose assistance I gratefully acknowledge.