Abstract: Conceptualists have it that the representational content of perceptual experience is determined by the concepts a subject applies in having such an experience. Conceptualists like Bill Brewer [1999] and John McDowell [1994] have laid particular emphasis on demonstrative concepts in trying to account for the fact that subjects can perceive and discriminate very many specific shades of colour in experience. Against this, it has been objected that such demonstrative concepts have incoherent conditions of extension and/or of individuation, due to the fact that chromatic indiscriminability is non-transitive. In this paper, I consider three different versions of this objection and show why each fails

Abstract: Suppose you are presented with three red objects. You are then asked to take a careful look at each possible pair of objects, and to decide whether or not their members look chromatically the same. You carry out the instructions thoroughly, and the following propositions sum up the results of your empirical investigation:

i. red object #1 looks the same in colour as red object #2.

ii. red object #2 looks the same in colour as red object #3

Abstract: Fallibilists about looks deny that the relation of looking the same as is non-transitive. Regarding familiar examples of coloured patches suggesting that such a relation is non-transitive, they argue that, in fact, indiscriminable adjacent patches may well look different, despite their perceptual indiscriminability: it’s just that we cannot notice the relevant differences in the chromatic appearances of such patches. In this paper, I present an argument that fallibilism about looks requires commitment to an empirically false consequence. To succeed in deflecting putative cases of non-transitivity, fallibilists would have to claim that there can’t be any perceptual limitations of any kind on human chromatic discrimination. But there are good reasons to think such limitations exist

Abstract: Drawing on work in psychophysics, psychometrics, and sensory neurophysiology, Clark analyzes the character and defends the integrity of psychophysical explanations of qualitative facts, arguing that the structure of such explanations is sound and potentially successful

Abstract: Most solutions to the sorites reject its major premise, i.e. the quantified conditional . This rejection appears to imply a discrimination between two elements that are supposed to be indiscriminable. Thus, the puzzle of the sorites involves in a fundamental way the notion of indiscriminability. This paper analyzes this relation and formalizes it, in a way that makes the rejection of the major premise more palatable. The intuitive idea is that we consider two elements indiscriminable by default, i.e. unless we know some information that discriminates between them. Specifically, following Rough Set Theory, two elements are defined to be indiscernible if they agree on the vague property in question. Then, a is defined to be indiscriminable from b if a is indiscernible by default from b . That is to say, a is indiscriminable from b if it is consistent to assume that a and b agree on the relevant vague property

Abstract: I argue in this paper that the existence of sorites series of color patches – series of color patches arranged so that the patches on each end look different in color though no two adjacent patches do – shows that the relation of same phenomenal charac­ter as is not a transitive relation. I then argue that the intransitivity of same phenomenal character as conflicts with certain versions of intentionalism, the view that an experiences phenomenal character is exhausted, or fully determined by its intentional content. Lastly, I consider various objections to the arguments and reply to them

Abstract: Since Nelson Goodman 1951, the assumption that phenomenal indiscriminability is non-transitive is taken generally for granted. Moreover, this assumption was used (by Goodman 1951, Travis 1985, Dummett 1975 and others) to argue against the existence or coherence of subjective and/or observational properties. Recently, however, the assumption has been questioned [Fara 2001] and I agree with Fara that the assumption is much more problematic than was thought, partly because it is not clear what is meant by the relation of phenomenal indiscriminability, and partly because it is not clear how to interpret ideas such as continuous change, and the limitations of our power of perceptual discrimination. In this paper I will bypass the question of the transitivity of phenomenal indiscriminability. I will use only the assumption about the existence (or even the possibility of existence) of a phenomenal sorites. This assumption is less controversial, and accepted (at least the version I will use) by opponents and defenders of transitivity alike. I will argue that the incoherence of 'red' (as response-dependent or purely observational) can be derived without committing ourselves to a view on the question of transitivity, and I will use this incoherence, to argue against the account of 'red' as a response-dependent concept

Abstract: 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.

Abstract: In her recent book Anti-Individualism and Knowledge, Jessica Brown has presented a novel answer to the self-knowledge achievement problem facing the proponent of anti-individualism. She argues that her answer is to be preferred to the traditional answer (based on Burge, 1988a). Here I present three objections to the claim that her proposed answer is to be preferred. The significance of these objections lies in what they tell us about the nature of the sort of knowledge that is in dispute. Perhaps the most important lesson I draw from this discussion is that, given the nature of knowledge of one's own thoughts, discriminability (from relevant alternatives) is not a condition on knowledge as such

Abstract: I argue that, contrary to widespread philosophical opinion, phenomenal indiscriminability is transitive. For if it were not transitive, we would be precluded from accepting the truisms that if two things look the same then the way they look is the same and that if two things look the same then if one looks red, so does the other. Nevertheless, it has seemed obvious to many philosophers (e.g. Goodman, Armstrong and Dummett) that phenomenal indiscriminability is not transitive; and, moreover, that this non-transitivity is straightforwardly revealed to us in experience. I show this thought to be wrong. All inferences from the character of our experience to the non-transitivity of indiscriminability involve either a misunderstanding of continuity, a mistaken interpretation of the idea that we have limited powers of discrimination, or tendentious claims about what our experience is really like; or such inferences are based on inadequately supported premisses, which though individually plausible are jointly implausible

Abstract: Let's be externalists about perceptual consciousness and think the form of veridical perceptual consciousness includes /seeing this or that mind-independent particular and its colors/. Let's also take internalism seriously, granting that spectral inversion and hallucination can be "phenomenally" the same as normal seeing. Then perceptual consciousness and phenomenality are different, and so we need to say how they are related. It's complicated!

Phenomenal sameness is (against all odds) /reflective indiscriminability/. I build a "displaced perception" account of reflection on which indiscriminability stems from shared "qualia". Qualia are compatible with direct realism: while they generate an explanatory gap (and colors do not), so does /seeing/; qualia are excluded from perceptual consciousness by its "transparency"; instead, qualia are aspects of thought about the perceived environment.

The asymmetry between my treatments of color and seeing is grounded in the asymmetry between ignorance and error: while inversion shows that normal subjects are ignorant of the natures of the colors, hallucination shows not that perceivers are ignorant of the nature of seeing but that hallucinators are prone to error about their condition. Past literature has treated inversion and hallucination as on a par: externalists see error in both cases, while internalists see mutual ignorance. My account is so complicated because plausible results require mixing it up.

Abstract: Perception represents colors inexactly. This inexactness results from phenomenally manifest noise, and results in apparent violations of the transitivity of perceptual indiscriminability. Whether these violations are genuine depends on what is meant by 'transitivity of perceptual indiscriminability'.

Abstract: Inspired by the writings of J. M. Hinton (1967a, 1967b, 1973), but ushered into the mainstream by Paul Snowdon (1980–1, 1990–1), John McDowell (1982, 1986), and M. G. F. Martin (2002, 2004, 2006), disjunctivism is currently discussed, advocated, and opposed in the philosophy of perception, the theory of knowledge, the theory of practical reason, and the philosophy of action. But what is disjunctivism?

Abstract: In this paper, I argue that those who accept the conceptualist view in the philosophy of perception should reject the traditional view that colour indiscriminability is non-transitive. I start by outlining the general strategy that conceptualists have adopted in response to the familiar ‘fineness of grain’ objection, and I show why a commitment to what I call the indiscriminability claim seems to form a natural part of this strategy. I then show how together, the indiscriminability claim and the non-transitivity claim –the claim that colour indiscriminability is non-transitive –entail a further, suspicious-looking claim that I call the problematic claim. My argument then splits into two parts. In the first part, I show why the conceptualist does indeed need to reject the problematic claim. Given that this claim is jointly entailed by the indiscriminability claim and the non-transitivity claim, the conceptualist is then left with a straight choice: reject the indiscriminability claim, or reject the non-transitivity claim. In the second part, I then explain why the conceptualist should choose the latter option

Abstract: According to the epistemic theory of hallucination, the fundamental psychological nature of a hallucinatory experience is constituted by its being ‘introspectively indiscriminable’, in some sense, from a veridical experience of a corresponding type. How is the notion of introspective indiscriminability to which the epistemic theory appeals best construed? Following M. G. F. Martin, the standard assumption is that the notion should be construed in terms of negative epistemics: in particular, it is assumed that the notion should be explained in terms of the impossibility that a hallucinator might possess a certain type of knowledge on a certain basis. I argue that the standard assumption is mistaken. I argue that the relevant notion of introspective indiscriminability is better construed in terms of positive epistemics: in particular, I argue that the notion is better explained by reference to the fact that it would be rational for a hallucinator positively to make a certain type of judgement, were that judgement made on a certain basis

Abstract:  I defend, to a certain extent, the traditional view that perceptual indiscriminability is non-transitive. The argument proceeds by considering important recent work by Benj Hellie: Hellie argues that colour perception represents ‘inexactly’, and that this results in violations of the transitivity of colour indiscriminability. I show that Hellie’s argument remains inconclusive, since he does not demonstrate conclusively that colour perception really does represent inexactly. My own argument for the non-transitivity of perceptual indiscriminability uses inexactness instead as one horn of a dilemma: the key idea is that there is a class of perceptual experiences which might plausibly be supposed either to represent inexactly or to represent exactly—but which demonstrate the non-transitivity of perceptual indiscriminability either way

Abstract: The Academics offered an argument from twins or perceptually indiscernible objects and an argument from dreams or madness in support of the indiscernibility thesis: that every true perceptual impression is such that some false impression just like it is possible. I claim that these arguments, unlike modern sceptical arguments, are supposed to establish mere counterfactual rather than epistemic possibilities. They purport to show that for any true perceptual impression j, there are a number of alternative causal histories j might have had which would not have resulted in any change in the way in which j represents its object

Abstract: It is widely supposed that one family of sorites paradoxes, perhaps the most perplexing versions of the puzzle, owe at least in part to the nontransitivity of perceptual indiscriminability. To a first approximation, perceptual indiscriminability is the relationship obtaining among objects (stimuli) that appear identical in some perceptual respect—for example hue, or pitch, or texture. Indiscriminable objects look the same, or sound the same, or feel the same. Received wisdom has it that there are or could be series of objects _o__1…_o__n in which _o_₁ and _o_₂ are indiscriminable, _o_₂ and _o_3 are indiscriminable, etc., and _o_n-1 and_ o_n are indiscriminable, but _o_1 and _o_n are discriminably different. For example, there could be a series of colored patches so ordered that each patch looks the same in hue as its immediate neighbors but the whole progresses from a clear case of red to a clear case of orange. On the assumption that an observational word like ‘red’ applies to both if to either of a pair of perceptually indiscriminable items, the absurd conclusion of the sorites comes into view. Crispin Wright explains

Abstract: Of the many families of words that are thought to be vague, so-called observational predicates may be both the most fascinating and the most confounding. Roughly, observational predicates are terms that apply to objects on the basis of how those objects appear to us perceptually speaking. ‘Red’, ‘loud’, ‘sweet’, ‘acrid’, and ‘smooth’ are good examples. Delia Graff explains that a “predicate is observational just in case its applicability to an object (given a fixed context of evaluation) depends only on the way that object appears” (2001, 3). By the same token observational predicates are, as Crispin Wright observes, terms “whose senses are taught entirely by ostension” (1976). Like other vague predicates, observational words appear to generate sorites paradoxes. Consider for example a series of 20 colored patches progressing from a clearly red one to a clearly orange one, so ordered that each patch is just noticeably different in hue from the one before. The following argument then seems forced upon us: (1) Patch #1 is red. (2) Any patch that differs only slightly in hue from a red patch is itself red. (3) Therefore patch #20 is red. Premise (2) expresses what Wright has called the tolerance of ‘red’: the application of the predicate tolerates small changes in a decisive parameter (here, hue). Of course, most vague predicates, hence most versions of the sorites, are not observational. For instance, given a series of..

Abstract: 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