Online research in philosophy

A direct realist theory of perceptual justification. I take a ground-up approach, beginning with a theory of subjective rationality understood in terms of first-person rational explicability of the stream of consciousness. I mathematize this picture via a Tractarian spin on a semantical framework developed by Rayo. Perceptual states justify by being 'receptive': rationally inexplicable intentional states encoded in sentences that are analytic. Direct realists working within this framework should say that when one is taken in by hallucination one's overall picture of the world is incoherent; in this sense, a belief based on delusive hallucination can be provided with exculpation but not with justification.

Many philosophers are skeptical about disjunctivism—a theory of perceptual experience which holds roughly that a situation in which I see a banana that is as it appears to me to be (the good case) and one in which I have a hallucination as of a banana (a certain kind of bad case) are mentally completely different. Often this skepticism is rooted in the suspicion that such a view cannot adequately account for the bad case—in particular, (i) that such a view cannot explain why what it’s like to have a hallucination can be exactly like what it’s like to have a veridical experience, (ii) that it cannot explain why the hallucination I have in the bad case is subjectively indistinguishable from the kind of experience I have in the good case, and (iii) that it cannot offer a viable account of the nature of hallucination.

In this paper, I argue that a proper formulation of disjunctivism can avoid these objections. Disjunctivism should be formulated as the weakest claim required to preserve its primary motivation, viz., Naïve Realism—the view that veridical experience fundamentally consists in the subject perceiving entities in her environment. And the weakest claim required to preserve Naïve Realism allows for many sorts of commonalities across the good and hallucinatory cases, commonalities that can be marshaled in responding to the objections. Most importantly, disjunctivism properly formulated is compatible with “positive” accounts of the nature of hallucination (as against M.G.F. Martin’s widely accepted argument to the contrary).

Finding disjunctivist versions of direct realism unexplanatory, Mark Johnston [(2004). Philosophical Studies, 120, 113–183] offers a non-disjunctive version of direct realism in its place and gives a defense of this view from the problem of hallucination. I will attempt to clarify the view that he presents and then argue that, once clarified, it either does not escape the problem of hallucination or does not look much like direct realism.

Of all the problems attending the sense-datum theory, arguably the deepest is that it draws a veil of appearances over the external world. Today, the sense-datum theory is widely regarded as an overreaction to the problem of hallucination. Instead of accounting for hallucination in terms of intentional relations to sense data, it is often thought that we should account for it in terms of intentional relations to properties. In this paper, however, I argue that in the versions that might address the problem of hallucination, this newer account is guilty of a vice similar to sense-datum theory’s: it draws a veil of abtracta over the concrete world.

Disjunctivism about perceptual appearances, as I conceive of it, is a theory which seeks to preserve a naïve realist conception of veridical perception in the light of the challenge from the argument from hallucination. The naïve realist claims that some sensory experiences are relations to mind-independent objects. That is to say, taking experiences to be episodes or events, the naïve realist supposes that some such episodes have as constituents mind-independent objects. In turn, the disjunctivist claims that in a case of veridical perception like this very kind of experience that you now have, the experiential episode you enjoy is of a kind which could not be occurring were you having an hallucination. The common strategy of arguments from hallucination set out to show that certain things are true of hallucinations, and hence must be true of perceptions. For example, it is argued that hallucinations must have non-physical objects of awareness, or that such states are not relations to anything at all, but are at best seeming relations to objects. In insisting that veridical perceptual experience is of a distinct kind from hallucination, the disjunctivist denies that any of these conceptions of hallucination challenges our conception of veridical perceptions as relations to mind-independent objects. More specifically, I assume that the disjunctivist advocates naïve realism because they think that this position best articulates how sensory experience seems to us to be just through reflection. If the disjunctivist is correct in this contention, then anyone who accepts the conclusion of the argument from hallucination must also accept that the nature of sensory experience is other than it seems to us to be. In turn, one may complain that any such error theory is liable to lead to sceptical consequences. A Humean scepticism about the senses launches a challenge about our knowledge of the world through questioning the conception we have of what sense experience is, and how it can provide knowledge of the world..

Early formulations of disjunctivism about perception refused to give any positive account of the nature of hallucination, beyond the uncontroversial fact that they can in some sense seem to the same to the subject as veridical perceptions. Recently, some disjunctivists have attempt to account for hallucination in purely epistemic terms, by developing detailed account of what it is for a hallucinaton to be indiscriminable from a veridical perception. In this paper I argue that the prospects for purely epistemic treatments of hallucinations are dim, and that this undermines the case for disjunctivism.

Michael Martin aims to affirm a certain pattern of first-person thinking by advocating disjunctivism, a theory of perceptual experience which combines naive realism with the epistemic conception of hallucination. In this paper I argue that we can affirm the pattern of thinking in question without the epistemic conception of hallucination. The first part of my paper explains the link that Martin draws between the first-person thinking and the epistemic conception of hallucination. The second part of my paper explains how we can achieve Martin’s ambition without Martin’s theory. One resource that I enlist for this purpose is a naive-realist friendly conception of first-person access to experience. The metaphysical theory that I enlist is a form of naive realism that endorses an intentionalist or representationalist “common-factor” approach to veridical and hallucinatory experience. The third part of my paper briefly develops this theory.

Michael Martin aims to affirm a certain pattern of first-person thinking by advocating disjunctivism, a theory of perceptual experience which combines naive realism with the epistemic conception of hallucination. In this paper I argue that we can affirm the pattern of thinking in question without the epistemic conception of hallucination. The first part of my paper explains the link that Martin draws between the first-person thinking and the epistemic conception of hallucination. The second part of my paper explains how we can achieve Martin’s ambition without Martin’s theory. One resource that I enlist for this purpose is a naive-realist friendly conception of first-person access to experience. The metaphysical theory that I enlist is a form of naive realism that endorses an intentionalist or representationalist “common-factor” approach to veridical and hallucinatory experience. The third part of my paper briefly develops this theory.