Brains, Persons, and Society *** ABSTRACTS    Cervelli, Persone e Società ***ABSTRACTS

Annalisa Coliva
Facoltà di Lettere e Filosofia, Università di Modena

 What’s wrong with Moore’s Proof?

 In the last few years there has been a resurgence of interest in Moore’s “Proof of the existence of an external world”, which is now usually rendered thus:

(I) Here is a hand
(II) If there is a hand here, there is an external world
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(III) There is an external world

In the first part of the paper I consider the contemporary debate, triggered by Crispin Wright and further fostered by Jim Pryor. I conclude that Pryor hasn’t given us any reasons to believe, against Wright, that Moore’s Proof is epistemologically sound – that it does not presuppose a warrant for its own conclusion, in order for premise (I) to be warranted in the first place – and that, instead, it is merely dialectically ineffective – that is, such that it can’t convince someone, like a skeptic, who already doubts that there is an external world. Still, in my view, this doesn’t entail that Wright’s claim that there must be an independent warrant for (III) in order for (I) to be warranted in the first place is right either. For a third view is possible: that the mere assumption or taking it for granted that there is an external world, without any warrant to do so, is indeed necessary – contrary to what Pryor maintains – to take one’s sense experience as a warrant for (I).

In the second part of the paper I develop the details of this third view. Firstly, I distinguish it from externalist proposals that would claim that the truth of (III) allows us to take our sense experience as a warrant for (I) and maintain that no such externalist construal would do as a response to the skeptic’s second-order challenge of claiming a warrant for our ordinary empirical propositions such as (I).

Secondly, I distinguish the third view from so-called “naturalist” proposals in epistemology, such as Strawson’s reading of Wittgenstein’s remarks in On certainty. I argue that it would be no response to a skeptic, but, in effect, an endorsement of his view, to say that it is part of our “nature” or “form of life” to take certain things for granted, such as the existence of an external world, although we have no rational ground to do so.

Finally, I distinguish it from Wright’s more recent proposals regarding what he calls “entitlement” – that is, the idea that although we may have no evidential ground in favor of (III), we would still have a non-evidential one, suitably redeemed by means of philosophical arguments. In particular, I stress the fact that, contrary to Wright’s proposal, the third view does not require any kind of warrant, evidential or otherwise, for taking (III) for granted.

I then take up the issue of how such a third view can indeed confront the skeptical challenge. I argue that the skeptic’s challenge is indeed a second-order one. That is, a challenge to claim that taking (III) for granted, although itself done without any kind of warrant, is rational nonetheless. Then I maintain that a suggestive direction – no doubt needing further development – in order to show how one can claim the rationality of such an acceptance, despite its being groundless, is to exploit the following analogy: just as it is perfectly rational to accept the rules of a game one wants, or needs to play, despite the fact that one has no warrant for them – for regarding them as somehow correct –, so it can be equally rational to accept the presuppositions of our most basic empirical practices if we are to engage in them. In particular, it can be rational to accept the presupposition of our language game of asking, giving and assessing reasons for and against ordinary empirical beliefs, if we are to engage in it. According to the third view (III) is such a presupposition for, unless it is accepted, no empirical warrant for or against
any empirical proposition could ever be acquired. So, trusting it is, for those who want or need to participate in the basic “game” of confirming or disconfirming empirical information, rational after all, although unsupported by warrant, evidential or otherwise.

I conclude by arguing that according to the third view, Moore’s Proof appears unsatisfactory because any genuine proof entails open-mindedness with respect
to its conclusion, for which the proof itself should provide a warrant. Moore’s Proof would thus entail open-mindedness with regard to a presupposition – (III) – of the very epistemic practice which, by the lights of the Proof itself, should produce a justification for (III). Such open-mindedness, however, can’t be attained if one is going to engage in that very epistemic practice. Hence, on the third view, Moore’s Proof fails because its preparatory conditions, by its own lights, can’t be attained. In this sense, Moore’s Proof is self-defeating.