Disjunctivism

What are hallucinations? A common view in the philosophical literature is that hallucinations are degenerate kinds of perceptual experience. I argue instead that hallucinations are degenerate kinds of sensory imagination. As well as providing a good account of many actual cases of hallucination, the view that hallucination is a kind of imagination represents a promising account of hallucination from the perspective of a disjunctivist theory of perception like naïve realism. This is because it provides a way of giving a positive (...) characterisation of hallucination—rather than characterising hallucinations in negative, relational, terms as mental events that are subjectively indistinguishable from veridical perceptual experiences. (shrink)

According to disjunctivism the object of perception is a part of the perceptual experience. This however raises the question of what the other constituents of the perceptual experience might be. In this paper I suggest that there may be no answer to this question that does not violate another core claim of disjunctivism, viz. that veridical perceptual experiences are experiences of different kinds than hallucinatory experiences.

In a recent paper, Berger and Nanay consider, and reject, three ways of addressing the phenomenon of unconscious perception within a naïve realist framework. Since these three approaches seem to exhaust the options open to naïve realists, and since there is said to be excellent evidence that perception of the same fundamental kind can occur, both consciously and unconsciously, this is seen to present a problem for the view. We take this opportunity to show that all three approaches considered remain (...) perfectly plausible ways of addressing unconscious perception within a naïve realist framework. So far from undermining the credibility of naïve realism, Berger and Nanay simply draw our attention to an important question to be considered by naïve realists in future work. Namely, which of the approaches considered is most likely to provide an accurate account of unconscious perception in each of its purported incarnations? (shrink)

Illusions are thought to make trouble for the intuition that perceptual experience is "open" to the world. Some have suggested, in response to the this trouble, that illusions differ from veridical experience in the degree to which their character is determined by their engagement with the world. An understanding of the psychology of perception reveals that this is not the case: veridical and falsidical perceptions engage the world in the same way and to the same extent. While some contemporary vision (...) scientists propose to draw the distinction between veridical experience and illusion in terms of the satisfaction or non-satisfaction of “hidden assumptions” deployed in the course of normal perceptual inference, I argue for a different approach. I contend that there are, in a sense, no illusions – illusions are as “open” as veridical experiences. Percepts lack the kinds of intentional content that would be needed for perceptual misrepresntation. My view gives a satisfying solution to a philosophical problem for disjunctivism about the good case/bad case distinction: with respect to illusions, every "bad case" of seeing an X can be equally well construed as a "good case" of seeing some Y (different from X). -/- . (shrink)

Ordinary people tend to be realists regarding perceptual experience, that is, they take perceiving the environment as a direct, unmediated, straightforward access to a mindindependent reality. Not so for (ordinary) philosophers. The empiricist influence on the philosophy of perception, in analytic philosophy at least, made the problem of perception synonymous with the view that realism is untenable. Admitting the problem (and trying to offer a view on it) is tantamount to rejecting ordinary people’s implicit realist assumptions as naive. So what (...) exactly is the problem? We can approach it via one of the central arguments against realism – the argument from hallucination. The argument is intended as a proof that in ordinary, veridical cases of perception, perceivers do not have an unmediated perceptual access to the world. There are many versions of it; I propose the following1: 1. Hallucinations that are subjectively indistinguishable from veridical perceptions are possible. 2. If two subjective states are indistinguishable, then they have a common nature. 3. The contents of hallucinations are mental images, not concrete external objects. 4. Therefore, the contents of veridical perceptions are mental images rather than concrete external objects. The key move is, I believe, from the fact that hallucinations that are subjectively indistinguishable from cases of veridical perception are possible to an alleged common element, factor, or nature, in the form of a mental state, in the two cases – that is, premise 2. Disjunctivism, at its core, can be taken as simply denying this move, and arguing that all that follows from the premise stating the possibility of hallucinations that are subjectively indistinguishable from cases veridical perception is that there is a broader category, that of “experience as of...”, which encompasses both cases.. (shrink)

Context: Direct realism is a non-reductive, anti-representationalist theory of perception lying at the heart of mainstream analytic philosophy, where it is currently generating a lot of interest. For all that, it is widely held to be both controversial and anti-scientific. On the other hand, the sensorimotor theory of perception initially generated a lot of interest within enactive philosophy of cognitive science, but has arguably not yet delivered on its initial promise. Problem: I aim to show that the sensorimotor theory and (...) direct realism complement each other, and that the result is a philosophically radical, but fully scientifically realised, theory of perception. Method: The article uses philosophical analysis and discussion. It also draws on empirical evidence from the relevant cognitive sciences. Results: Direct realism can be augmented by sensorimotor theory to become a scientifically tractable alternative to the mainstream, representationalist research programme within cognitive science. Implications: The article aims to further clarify the philosophical importance of the sensorimotor approach to perception. It also aims to show that the apparently radical claim that we perceive objects themselves is amenable to normal scientific study. Constructivist content: Objects are analysed as a kind of collaboration between the world and the perceiver. On this account, we can never perceive outside the categories of our own understanding, but we do perceive genuinely outside our own heads. Thus, the approach here is not exactly constructivism, though it shares many goals and results with constructivism. (shrink)

On the face of it, Maurice Merleau-Ponty’s views bear a strong resemblance to contemporary disjunctivist theories of perception, especially John McDowell’s epistemological disjunctivism. Like McDowell , Merleau-Ponty seems to be a direct realist about perception and holds that veridical and illusory perceptions are distinct. This paper furthers this comparison. Furthermore, it is argued that elements of Merleau-Ponty’s thought provide a stronger case for McDowell’s kind of epistemological view than McDowell himself provides. Merleau-Ponty’s early thought can be used to develop a (...) unique version of epistemological disjunctivism that is worth consideration alongside contemporary views on perceptual knowledge. (shrink)

A theory is disjunctive insofar as it distinguishes genuine from non-genuine cases of some phenomenon P on the grounds that no salient feature of cases of one type is common to cases of the other type. Genuine and non-genuine cases of P are, in this sense, fundamentally different. Those who advocate disjunctivist theories have (for the most part) been concerned with perception and perceptual knowledge. This entry outlines two such theories: the disjunctivist theory of experience (cf. Brewer, Hinton, Martin, Snowdon, (...) Travis) and the disjunctivist theory of appearances (McDowell). (shrink)

This paper aims to shed new light on certain philosophical theories of perceptual experience by examining the semantics of perceptual ascriptions such as “Jones sees an apple.” I start with the assumption, recently defended elsewhere, that perceptual ascriptions lend themselves to intensional readings. In the first part of the paper, I defend three theses regarding such readings: I) intensional readings of perceptual ascriptions ascribe phenomenal properties, II) perceptual verbs are not ambiguous between intensional and extensional readings, and III) intensional perceptual (...) ascriptions have a relational form. The second part of the paper describes the implications of I-III for theories of perceptual experience. I argue that I-III support and reconcile the three main views of perceptual experience, relationalism, disjunctivism, and representationalism. However, I-III leave open at least one important point of contention: particularism, the view that we experience external objects. I conclude by exploring the implications of accepting or denying particularism given I-III. (shrink)

The question how to account for illusion has had a prominent role in shaping theories of perception throughout the history of philosophy. Prevailing philosophical wisdom today has it that phenomena of illusion force us to choose between the following two options. First, reject altogether the early modern empiricist idea that the core subjective character of perceptual experience is to be given simply by citing the object presented in that experience. Instead we must characterize perceptual experience entirely in terms of its (...) representational content. Second, retain the early modern idea that the core subjective character of experience is simply constituted by the identity of its direct objects, but admit that these must be mind-dependent entities, distinct from the mind-independent physical objects we all know and love. I argue here that the early modern empiricists had an indispensable insight. The idea that the core subjective character of perceptual experience is to be given simply by citing the object presented in that experience is more fundamental than any appeal to perceptual content, and can account for illusion, and indeed hallucination, without resorting to the problematic postulation of any such mind-dependent objects. (shrink)

I argue that McDowell-style disjunctivism, as the position is often cashed out, goes wrong because it takes the good epistemic standing of veridical perception to be grounded in “manifest” facts which do not necessarily satisfy any epistemic constraints. A better form of disjunctivism explains the difference between good and bad cases in terms of epistemic constraints that the states satisfy. This view allows us to preserve McDowell’s thesis that good cases make facts manifest, as long as manifest facts must satisfy (...) epistemic constraints. (shrink)

Naive realism is one of the oldest theories of perception. To a first approximation, naive realism is the view that perception is a direct relation between a subject and an object. Many historical philosophers (from Locke to Russell) argued that naive realism must be rejected on the grounds that hallucinations are perceptual experiences without an object. Contemporary philosophers have resurrected the theory by insisting that genuine cases of perception have a different structure or a different metaphysical status than non-genuine ones. (...) This version of naive realism has come to be known as ‘disjunctivism’. Epistemological disjunctivism and disjunctivism about phenomenal belief, or what I shall call ‘Epistemological disjunctivism’, have also gained popularity in recent years. More recently disjunctivist accounts of bodily movements, abilities and reasons for action have entered the philosophical scene. This entry focuses on the contemporary debate about disjunctivism: its characterization, its motivation and its potential shortcomings. (shrink)

This essay is a long one. It is not meant to be read in a single sitting. Its structure is as follows. In section I, I explicate perceptual anti-individualism. Section II centers on the two aspects of the representational content of perceptual states. Sections III and IV concern the nature of the empirical psychology of vision, and its bearing on the individuation of perceptual states. Section V shows how what is known from empirical psychology undermines disjunctivism and hence certain further (...) views that entail it, including naive realism. In Section VI, I raise a further point against disjunctivism. Section VII indicates how general reflection on perceptual perspective and epistemic ability supports the constraints from empirical psychology. It also explains how reflection on veridicality conditions, psychological explanation, and cognitive ability conspire to force recognition of the two kinds of representation mentioned in the preceding paragraph. In the Appendix, I criticize attempts to support disjunctivism. (shrink)

Classic texts that define the disjunctivist theory of perception.

This essay surveys the varieties of disjunctivism about perceptual experience. Disjunctivism comes in two main flavours, metaphysical and epistemological.

The argument from illusion/hallucination have been proposed many times as supporting the strong conclusion that we are always perceiving directly sense-data. In Sense & Sensibilia, Austin argues that this argument is based on a “mass of seductive (mainly verbal) fallacies”. In this paper, I argue that Austin's argumentative moves to deconstruct the argument from illusion is better understood if they are seen as due to his implicit commitment to some disjunctivist conception of perception. His considerations should be taken as a (...) depth discussion about how to conceive perception. If we conceive the perceptual capacity disjunctively, even the weaker conclusion that we sometimes perceive sense-data does not hold. In response to Austin, Ayer claimed that the strong conclusion of the argument from illusion could be sustained by the method of the possibility of error. I argue that this method alone does not sustain that conclusion and the controversy turns back to the conflict between different conceptions of perception. The argument from illusion is philosophically interesting by putting in evidence the problem of how the perceptual capacity should be articulated and conceived. Although matters of fact are relevant to this question, they alone do not decide it. (shrink)

In his book, "Perception as a Capacity for Knowledge" (2011), John McDowell advocates that the warranty provided by perception is infallible. For such, it is necessary understanding the role reason plays for the constitution of genuine perceptual states. Through reason, we situate these states on the logical space of reasoning. So, we not only make of the perceptual state into an episode of knowledge, but we also acquire knowledge of how we arrived to that knowledge. McDowell argues that this condition (...) for knowledge - the possession of the capacity to situate a perceptual state in the logical space of reasoning - does not compromise him with intellectualism. In this paper, I defend that McDowell's internalism is not entirely exempt from intellectualism, and that internalism is more reasonable not only without intellectualism, but also without reflexivity. (shrink)

Is ruling out the possibility that one is dreaming a requirement for a knowledge claim? In “Philosophical Scepticism and Everyday Life” (1984), Barry Stroud defends that it is. In “Others Minds” (1970), John Austin says it is not. In his defense, Stroud appeals to a conception of objectivity deeply rooted in us and with which our concept of knowledge is intertwined. Austin appeals to a detailed account of our scientific and everyday practices of knowledge attribution. Stroud responds that what Austin (...) says about those practices is correct in relation to the appropriateness of making knowledge claims, but that the skeptic is interested in the truth of those claims. In this paper, we argue that Stroud’s defense of the alleged requirement smuggles in a commitment to a kind of internalism, which asserts that the perceptual justification available to us can be characterized independently of the circumstances in which we find ourselves. In our reading of Austin, especially of Sense & Sensibilia, he rejects that kind of internalism by an implicit commitment to what is called today a “disjunctive” view of perception. Austin says that objectivity is an aspect of knowledge, and his disjunctivism is part of an explanation of why the alleged requirement is not necessary for a knowledge claim. Since both Stroud and Austin are committed to the objectivity of knowledge, Stroud may ask which view of perceptual knowledge is correct, whether the internalist or the disjunctive. We argue that by paying closer attention to what Austin says about our practices of knowledge attribution, one can see more clearly that it is grounded not only on a conception of objectivity, but also on a conception of ourselves as information agents, a conception that is as deeply rooted as that of the objectivity of knowledge. This gives us moral and practical reasons to favor the disjunctive view of perception. (shrink)

Philosophers of mind have long been interested in the relation between two ideas: that causality plays an essential role in our understanding of the mental; and that we can gain an understanding of belief and desire by considering the ascription of attitudes to people on the basis of what they say and do. Many have thought that those ideas are incompatible. William Child argues that there is in fact no tension between them, and that we should accept both. He shows (...) how we can have a causal understanding of the mental without having to see attitudes and experiences as internal, causally interacting entities and he defends this view against influential objections. The book offers detailed discussions of many of Donald Davidson's contributions to the philosophy of mind, and also considers the work of Dennett, Anscombe, McDowell, and Rorty, among others. Issues discussed include: the nature of intentional phenomena; causal explanation; the character of visual experience; psychological explanation; and the causal relevance of mental properties. (shrink)

In this paper I argue that McDowell’s brand of disjunctivism about perceptual knowledge is ill-motivated. First, I present a reconstruction of one main motivation for disjunctivism, in the form of an argument that theories that posit a “highest common factor” between veridical and non-veridical experiences must be wrong. Then I show that the argument owes its plausibility to a failure to distinguish between justification and warrant (where “warrant” is understood as whatever has to be added to true belief to yield (...) knowledge). (shrink)

Disjunctivism about sensory experience is frequently put forward in defence of a particular conception of perception and perceptual experience known as naïve realism. In this paper I present an argument against naïve realism that proceeds through a rejection of disjunctivism. If the naïve realist must also be a disjunctivist about the phenomenal nature of experience, then naïve realism should be abandoned.

Disjunctivists hold that perceiving external objects is fundamentally different from any experiential state that is not a perception. In fact, roughly speaking, disjunctivists say that they have nothing in common. Suppose that it appears to someone as though she perceives something. Disjunctivists say that there are two disparate sorts of facts that could make this true. Either she is genuinely perceiving something, or she is in an experiential state of merely apparent perception. An apparent perception is fundamentally unlike a perception. (...) Disjunctivists differ in what they say the fundamental difference is. We’ll get to some of that shortly. First I’ll say where I’m headed here. (shrink)

It is now common to distinguish Metaphysical from Epistemological Disjunctivism. It is equally common to suggest that it is at least not obvious that the latter requires a commitment to the former: at the very least, a suitable bridge principle will need to be identified which takes one from the latter to the former. This paper identifies a plausible-looking bridge principle that takes one from the version of Epistemological Disjunctivism defended by John McDowell and Duncan Pritchard, which I label Reflective (...) Epistemological Disjunctivism, or (RED), to Metaphysical Disjunctivism. Moreover, it identifies a modification the proponent of (RED) could, and should, make to the Internalist component of their theory, and argues that the commitment to Metaphysical Disjunctivism remains, even if such a modification is made. The upshot is that the commitment to Metaphysical Disjunctivism on the part of (RED) is shown to be particularly robust. (shrink)

From the early modern period, Western epistemologists have often been concerned with a rigorous notion of epistemic justification, epitomized in the work of Descartes: properly held beliefs require insulation from extreme skepticism. To the degree that veridical cognitive states may be indistinguishable from non-veridical states, apparently veridical states cannot enjoy high-grade positive epistemic status. Therefore, a good believer begins from what are taken to be neutral, subjective experiences and reasons outward—hopefully identifying the kinds of appearances that properly link up to (...) the world and those that do not. Good beliefs, beliefs that are justified (warranted, etc.), are those that a believer has .. (shrink)

de Brasi, Leandro_Epistemological Disjunctivism, by Duncan Pritchard.

How are we to account for the epistemic contribution of our perceptual experiences to the reasonableness of our perceptual beliefs? It is well known that a conception heavily influenced by Cartesian thinking has it that experiences do not enable the experiencing subject to have direct epistemic contact with the external world; rather, they are regarded as openness to a kind of private inner realm that is interposed between the subject and the world. It turns out that if one wants to (...) insist that perceptual experiences provide epistemic reasons for perceptual beliefs about the external world as we pre-reflectively take it to be, then one should find a way of avoiding Cartesianism. Here are the two main aims of this paper: firstly, identify the premise that is doing the heavy-lifting work in the Cartesian thinking; and, secondly, formulate an adequate way of denying that premise. The adequacy I claim for my formulation of a way of denying the premise will roughly amount to this: the way I offer is not as susceptible to Cartesian traps as other apparently available ways of denying the premise are. (shrink)

Duncan Pritchard has recently defended a view he calls ‘epistemological disjunctivism’, largely inspired by John McDowell. I argue that Pritchard is right to associate the view with McDowell, and that McDowell’s ‘inference-blocking’ argument against the sceptic succeeds only if epistemological disjunctivism is accepted. However, Pritchard also recognises that epistemological disjunctivism appears to conflict with our belief that genuine and illusory experiences are indistinguishable (the ‘distinguishability problem’). Since the indistinguishability of experiences is the antecedent in the inference McDowell intends to block, (...) I suggest that his argument rests on an inconsistent set of premises. In support of this, I show that Pritchard’s response to the distinguishability problem is incompatible with the conclusion of the ‘inference-blocking’ argument, and that the response available in McDowell’s work relies on a mistaken conception of fallibility. Either McDowell must deny the sceptic’s premise that perceptual experiences are indistinguishable, or he must give up his conclusion that perceptual warrant can be indefeasible. (shrink)

Perceptual experiences have been construed either as representational mental states—Representationalism—or as direct mental relations to the external world—Disjunctivism. Both conceptions are critical reactions to the so-called ‘Argument from Hallucination’, according to which perceptions cannot be about the external world, since they are subjectively indiscriminable from other, hallucinatory experiences, which are about sense-data ormind-dependent entities. Representationalism agrees that perceptions and hallucinations share their most specific mental kind, but accounts for hallucinations as misrepresentations of the external world. According to Disjunctivism, the phenomenal (...) character of perceptions is exhausted by worldly objects and features, and thus must be different from the phenomenal character of hallucinations. Disjunctivism claims that subjective indiscriminability is not the result of a common experiential ground, but is because of our inability to discriminate, from the inside, hallucinations from perceptions. At first sight, Representationalism is more congenial to the way cognitive science deals with perception. However, empirically oriented revisions of Disjunctivism could be developed and tested by giving a metacognitive account of hallucinations. Two versions of this account can be formulated, depending on whether metacognition is understood as explicit metarepresentation or as implicit monitoring of first-order informational states. The first version faces serious objections, but the second is more promising, as it embodies a more realistic view of perceptual phenomenology as having both sensory and affective aspects. Affectbased phenomenology is constituted by various metacognitive feelings, such as the feeling of being perceptually confronted with the world itself, rather than with pictures or mere representations. (shrink)

In recent years, it has become popular again to endorse relationalism about perception.1 According to this view, perceptions are essentially relational experiences and thus di er in nature from non-relational hallucinations. In this article, I assume that relationalism is true. The issue that I am generally interested in is rather which version of relationalism we should endorse, given that perceptions are relational. The standard answer to this question is Acquaintance Relationalism, the view that perceptions are relational in so far as (...) they acquaint us with objects in our environment. But my contention is that this view cannot account for two important aspects of perfect hallucinations, namely their property of being introspectively indistinguishable from perceptions and their property of having the same motivational force as veridical perceptions. Which alternative form of relationism should be endorsed instead (if any) is then an issue to be discussed at another occasion. (shrink)

In his paper, The Transparency of Experience, M.G.F. Martin has put forward a well- known – though not always equally well understood – argument for the disjunctivist, and against the intentional, approach to perceptual experiences. In this article, I intend to do four things: (i) to present the details of Martin’s complex argument; (ii) to defend its soundness against orthodox intentionalism; (iii) to show how Martin’s argument speaks as much in favour of experiential intentionalism as it speaks in favour of (...) disjunctivism; and (iv) to argue that there is a related reason to prefer experiential intentionalism over Martin’s version of disjunctivism. (shrink)

One central fact about hallucinations is that they may be subjectively indistinguishable from perceptions. Indeed, it has been argued that the hallucinatory experiences concerned cannot— and need not—be characterized in any more positive general terms. This epistemic conception of hallucinations has been advocated as the best choice for proponents of experiential (or “naive realist”) disjunctivism—the view that perceptions and hallucinations differ essentially in their introspectible subjective characters. In this chapter, I aim to formulate and defend an intentional alternative to experiential (...) disjunctivism called experiential intentionalism. This view not only enjoys some advantages over its rival but is also compatible with the epistemic conception of hallucinations, as well as with the disjunctivist view that perceptions and hallucinations differ essentially in their third-personal structures (e.g., their causal, informational, or reason-providing links to reality). It also maintains that there are actually two aspects to the subjective indistinguishability of mental episodes: (i) we cannot distinguish their first-personal characters in introspective awareness; and (ii) we cannot distinguish their third-personal structures in experiential awareness—that is, in how they are given to consciousness. While experiential disjunctivism makes the mistake of ignoring (ii) and reducing subjective indiscriminability to (i), experiential intentionalism correctly identifies (ii) as the primary source of the subjective indistinguishability of perception-like hallucinations. Accordingly, the intentional error involved in such hallucinations is due to the fact that we consciously experience them as possessing a relational structure. (shrink)

In this review article, I introduce a classification of metaphysical and epistemological forms of disjunctivism and critically discuss the essays on disjunctivism in the philosophy of perception, the philosophy of action and epistemology that are published in Fiona Macpherson and Adrian Haddock’s collection 'Disjunctivism: Perception, Action, Knowledge' (Oxford University Press, 2008).

In this paper, I would like to put forward the claim that, at least in some central cases, visualising consists literally in imagining seeing. The first section of my paper is concerned with a defence of the specific argument for this claim that M. G. F. Martin presents in his paper 'The Transparency of Experience' (Martin 2002). This argument has been often misunderstood (or ignored), and it is worthwhile to discuss it in detail and to illus­trate what its precise nature (...) is and why I take it to be sound. In the second section, I present a second and independent argument for the claim that visualising is imagining seeing, which is not to be found in Martin's writings, despite some crucial similarities with his own argument ‒ notably in the focus on the subjective aspects of visual experience. The last section deals with a particular objection to the idea that imagining takes perception as its direct object and says a bit more about how best to understand this claim. (shrink)

In his paper, The Transparency of Experience, M.G.F. Martin has put forward a well- known – though not always equally well understood – argument for the disjunctivist, and against the intentional, approach to perceptual experiences. In this article, I intend to do four things: (i) to present the details of Martin’s complex argument; (ii) to defend its soundness against orthodox intentionalism; (iii) to show how Martin’s argument speaks as much in favour of experiential intentionalism as it speaks in favour of (...) disjunctivism; and (iv) to argue that there is a related reason to prefer experiential intentionalism over Martin’s version of disjunctivism. (shrink)

This thesis offers a reassessment of the philosophical problem of scepticism about knowledge of the external world. It distinguishes between different forms of this sceptical problem and considers two kinds of response: a strategy developed by Tim Williamson, and a disjunctivist approach. Chapters one and two offer an introduction to the problem of scepticism: the sceptical arguments of Descartes and Hume are compared, and Williamson’s approach to scepticism is introduced. Chapter three considers three different ways of responding to Humean scepticism. (...) This chapter offers an interpretation of Stroud’s objection to externalism and considers whether disjunctivist accounts are vulnerable to a similar objection. Chapter four compares Williamson’s approach with one form of disjunctivist account. Central to this discussion is a distinction between responses to scepticism which question whether there is guaranteed epistemic access to one’s own mental states, and a disjunctivist account which proposes that the subject’s perspective on their conscious states is not grounded on a mode of knowing something independent of it. Chapter five considers a further debate about disjunctivism and scepticism. Wright’s objections to disjunctivist accounts are considered, and McDowell’s version of disjunctivism is compared with a Moorean response to scepticism. (shrink)

This book provides the first full-length treatment of disjunctivism about visual experiences in the service of defending a naive realist theory of veridical visual perception. It includes detailed theories of hallucination and illusion that show how such states can be indistinguishable from veridical experiences without sharing any common character.

In the first monograph in this exciting area since then, William Fish develops a comprehensive disjunctive theory, incorporating detailed accounts of the three ...

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. (shrink)

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. (shrink)