Online research in philosophy

1. The main tenet of the epistemic conception of hallucinations is that we can positively characterise their common makeup - if they share any at all - only in epistemic, but not in metaphysical terms.1 Hallucinations differ from perceptions in that they do not put us into contact with the world in such a way as to enable us to refer to mind-independent objects and acquire knowledge about them. And certain hallucinations are special in so far as they are, in a significant sense, subjectively indiscriminable from perceptions. According to the epistemic conception, these two claims - one being negative and metaphysical, the other positive and epistemic - capture all that can, and need to, be said about what these subjectively perception-like hallucinations have in common.2 The epistemic conception of hallucinations may be partly motivated by drawing attention to the observation that, while there is only one way in which perception can go right, there are many ways in which it can go wrong. Perception goes right just in case it relates us to the external world in the way just mentioned. In all other cases, it goes wrong; and it may fail to establish the required relation on different occasions for very different reasons.

One central fact about hallucinations is that they may be subjectively indistinguishable from perceptions. Indeed, it has been argued by M. G. F. Martin and others that the hallucinatory experiences concerned cannot — and need not — be characterised in any more positive general terms. This epistemic conception of hallucinations has been advocated as the best choice for proponents of experiential (or ‘na¨ıve realist’) disjunctivism — the view that perceptions and hallucinations differ essentially in their introspectible subjective characters. In this chapater, I aim to formulate and defend an intentional alternative to experiential disjunctivism called experiential intentionalism. This view does not only enjoy some advantages over its rival, but also can hold on to the epistemic conception of perception-like hallucinations. First of all, I try to spell out in a bit more detail in which sense hallucinations may be subjectively indistinguishable from perceptions, and why this leads us to erroneously judge them to be perceptions (cf. sections I–III and VIII). Then, I raise three challenges each for experiential disjunctivism and its orthodox intentionalist counterparts (cf. sections IV and V), notably in respect of the need to explicate why a perception-like hallucination still makes the same judgements reasonable from the subject’s perspective as the corresponding perceptions. And, finally, I propose my alternative both to experiential disjunctivism and to orthodox intentionalism. Experiential intentionalism takes perceptions and perception-like hallucinations to share a common character partly to be spelled out in intentional — and, hence, normative — terms (cf. sections VI and VII). The central thought is that the hallucinations concerned are intentionally — and erroneously — presented to us as perceptual relations to the world. I aim to show that the resulting view can meet all six challenges (cf. sections VI–VIII). I end..

Direct realists think that we can't get a clear view the nature of /hallucinating a white picket fence/: is it /representing a white picket fence/? is it /sensing white-picket-fencily/? is it /being acquainted with a white' picketed' sense-datum/? These are all epistemic possibilities for a single experience; hence they are all metaphysical possibilities for various experiences. Hallucination itself is a disjunctive or "multidisjunctive" category. I rebut MGF Martin's argument from statistical explanation for his "epistemic" conception of hallucination, but his view embeds in my view as a "reference-fixer".

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).

Abstract: How exactly should the relation between a veridical perception and a corresponding hallucination be understood? I argue that the epistemic notion of ‘indiscriminability’, understood as lacking evidence for the distinctness of things, is not suitable for defining this relation. Instead, we should say that a hallucination and a veridical perception involve the same phenomenal properties. This has further consequences for attempts to give necessary and sufficient conditions for the identity of phenomenal properties in terms of indiscriminability, and for considerations about the phenomenal sorites.

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.

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..

In the eyes of some of its critics, disjunctivism fails to support adequately the key claim that a particular hallucination might be indistinguishable from a certain kind of veridical perception despite the two states having nothing other than this in common. Scott Sturgeon, for example, has complained that disjunctivism ‘‘offers no positive story about hallucination at all’’ (2000: 11) and therefore ‘‘simply takes [indistinguishability] for granted’’ (2000: 12). So according to Sturgeon, what the disjunctivist needs to provide is a plausible explanation of just how two mental states which have no common component might be indistinguishable for their subject and this in turn will require the telling of a positive story about hallucination. This is the goal of the present essay.

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.

Disjunctivism, as a theory of visual experience, claims that the mental states involved in a “good case” experience of veridical perception and a “bad case” experience of hallucination differ, even in those cases in which the two experiences are indistinguishable for their subject. Consider the veridical perception of a bar stool and an indistinguishable hallucination; both of these experiences might be classed together as experiences (as) of a bar stool or experiences of seeming to see a bar stool. This might lead us to think that the experiences we undergo in the two cases must be of the same kind, the difference being that the former, but not the latter, is connected to the world in the right kind of way. Such a conjecture has been called a “highest common factor” or “common kind” assumption. At heart, disjunctivism consists in the rejection of this assumption. According the disjunctivist, veridical experiences and hallucinations do not share a common component. There are a host of interesting questions surrounding disjunctivism including: What is involved in the claims that good case and bad case experiences differ? Why might one might want to be a disjunctivist? What kinds of claims can the disjunctivist make about hallucination and illusion? These questions, and problems for the thesis, will be discussed as we proceed.