Tuesday, 13 February 2007

The Wright Objection

Following J. M. Hinton [1973], Paul Snowdon [1990] has argued that indistinguishable veridical and hallucinatory perceptual experiences belong to fundamentally different genera. Thus, veridical perceptual experiences (henceforth e1) are of one sort while hallucinatory perceptual experiences (henceforth e2) are of another fundamentally different sort, the only thing common to both being that they are introspectively indistinguishable from each other. The difference between e1 and e2 is, for Snowdon, is rooted in the fact that perceptual experiences are essentially relational.

John McDowell takes up Snowdon’s disjunctive conception and applies its insights to epistemological questions relating to our perceptual beliefs.1 According to McDowell, the epistemological upshot of the disjunction between e1 and e2 is that e1 places us in a better epistemic position than e2 does. On its own, this claim hardly seems controversial. For example, a reliabilist would agree that e1 places us in a better epistemic position than e2 since veridical perceptual experiences are a reliable source of true beliefs while hallucinations are not. However, what is most striking about McDowell’s claim that e1 puts us in a better epistemic position to e2 is that he rejects (extreme) forms of epistemic externalism:
[O]ne’s epistemic standing on some question cannot intelligibly be constituted, even in part, by matters blankly external to how it is with one subjectively. For how could such matters be other than beyond one’s ken? And how could matters beyond one’s ken make any difference to one’s epistemic standing? [McDowell 1998, p. 390]
I interpret ‘how it is with one subjectively’ to mean from the subject’s point of view. However, many critics have insisted that if e1 and e2 are subjectively indistinguishable, then from the subject’s point of view e1 could not possibly put one in a better epistemic position than e2. In this post I will sketch the version of this criticism put forward by Crispin Wright [2002].

Wright presents the following challenge to McDowell’s disjunctive analysis. Suppose S came to hold the demonstrative belief that that is an F. Does S’s justification for believing that that is an F transmit to the claim that S is not merely having a hallucination of an F? According to Wright, there is a ‘strong intuition’ that it does not since we have done nothing to rule out the unpropitious possibility [2002, p. 342]. Moreover, since ex hypothesi the hallucination in question is subjectively indistinguishable from a veridical perceptual experience, there is no way for the subject, based on that experience, to know that she is not suffering from a hallucination rather than having a veridical perceptual experience.

Wright applies the above argument to disjunctivism by appealing to the following four presuppositions, which he describes as the disjunctive template [Ibid, p. 343]:
(i) that A entails B;

(ii) that my justification2 for A consists in my being in a state which is subjectively indistinguishable from a state in which the relevant C would be true;

(iii) that C depicts a situation of a general kind incompatible with the reliable operation of the cognitive capacities involved in generating the putative warrant for A; and

(iv) that C would be true if B were false.
We may fill in the details of the disjunctive template thus: Let A be the proposition that that is an F. Let B be the entailed proposition that that is not a hallucination of an F; and let C take the form of a generalisation of the negation of B: It is not the case that I am having a perfect hallucination of an F. Given the above disjunctive template the question, according to Wright, is
What…can justify me in taking it that I have a warrant for A? Why not just reserve judgement and stay with the more tentative disjunction, Either (I have a warrant for) A, or C? [Ibid].
Wright maintains that to get beyond the disjunction [A V C], we must somehow discount C. That is, we can only maintain that ‘that is an F’ if we can discount the possibility that ‘that is not an F but merely an indistinguishable hallucination of an F’. However, to be entitled to discount C I must also be entitled to discount ~B since, ex hypothesi, C is merely the generalisation of B’s negation. However, to discount ~B I must have some prior entitlement to B independent of its entailment by A. Consequently, on pain of circularity, my justification for A fails to transmit to B.

The upshot of the above analysis is that, given the possibility of there being hallucinations that are subjectively indistinguishable from veridical perceptual experiences, we cannot take ourselves to be justified (as far as our perceptual beliefs are concerned) in believing anything beyond the disjunction [A V C].

We may further unpack the Wright objection as follows: Let us presuppose an internalist conception of epistemic justification such that for S to be justified in believing that P means that S has subjective access to that which constitutes her justification for believing that P. Let [E1 … En] stand for the maximal set of subjective properties of some experience e1. If there is some experience, e2, which is subjectively indistinguishable from e1, then e2 must also possess [E1 … En], or at least so the thought goes. (I am here assuming that the circle encompassing what is introspectively accessible is coextensive with the maximal set of subjective properties of a given experience.) Given the internalist requirement that S’s justification for believing that P must be introspectively accessible, S’s justification for believing that P must be derived from [E1 … En] or some subset thereof. Since e1 and e2 share [E1 … En] in common, and given the internalist requirement that S’s justification for believing that P be derived from [E1 … En], any evidence derived from e1 in support of S’s believing that P can also be derived from e2 in support of S’s believing that P. Thus, insofar as e1 and e2 are subjectively indistinguishable, there can be no difference between what being in e1 makes S justified in believing and what being in e2 makes S justified in believing. Ergo, e1 does not put S in a better epistemic position, from an internalist perspective, than e2.


1 It should be borne in mind that there are a number of significant differences between Snowdon’s and McDowell’s formulation of disjunctivism. For example, Snowdon focuses on locutions of object-perception, ‘S sees o’, while McDowell is interested in locutions of fact-perception, ‘S sees that p.’ Following McDowell, I will be using a version of fact-perception statements, ‘S sees that that is an F’.

2 Wright uses the word ‘warrant’.

Hinton, J.M. [1973]. Experiences. Clarendon Press: Oxford.

McDowell, J. [1998], ‘Criteria, Defeasibility, and Knowledge’, Meaning, Knowledge, and Reality, 369-94, London: Harvard University Press.

Snowdon, P. F. [1990], “The Objects of Perceptual Experience” Proceedings of the Aristotelian Society Supplementary Volume 64: 121–150.

Wright, C. [2002].‘(Anti-)Sceptics Simple and Subtle: G.E. Moore and John McDowell’, Philosophy and Phenomenological Research 65: 330 – 48.

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