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- Rafael de Clercq & Leon Horsten (2004). Perceptual Indiscriminability: In Defence of Wright's Proof. Philosophical Quarterly 54 (216):439-444.A series of unnoticeably small changes in an observable property may add up to a noticeable change. Crispin Wright has used this fact to prove that perceptual indiscriminability is a non-transitive relation. Delia Graff has recently argued that there is a 'tension' between Wright's assumptions. But Graff has misunderstood one of these, that 'phenomenal continua' are possible; and the other, that our powers of discrimination are finite, is sound. If the first assumption is properly understood, it is not in tension with but is actually implied by the second, given a plausible physical assumption.
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In the contemporary expanding literature on transmission failure and its connections with issues such as the Closure principle, the nature of perceptual warrant, Moore’s proof of an external world and the effectiveness of Humean scepticism, it has often been assumed that there is just one kind of it: the one made familiar by the writings of Crispin Wright and Martin Davies. Although it might be thought that one kind of failure is more than enough, Davies has recently challenged this view: apparently, there are more ways in heaven and earth that warrant can fail to transmit across valid inference from one (set of) belief(s) to another, than have been dreamt of in philosophy so far. More specifically, Davies thinks that a second kind of transmission failure has to be countenanced. He connects each kind of failure of transmission of warrant with two different kinds of epistemic project, respectively, and with the exploration of whether the current dispute between conservatives such as Wright, and liberals such as Jim Pryor, on the nature of perceptual warrant, would have a bearing on them. I point out why Davies’s second kind of transmission failure is indeed no such thing. I then move on to canvass another kind of transmission failure, different from the one studied by both Wright and Davies, and dependent on an alternative conception of the structure of empirical warrants, which I dub “moderatism”. I then consider how this alternative notion of transmission failure fares with respect to Moore’s proof, its relationship with Wright’s kind of transmission failure and with the Closure principle. In closing, I defend it from criticisms that can be elicited from Pryor’s recent work.
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.
According to Wright, Moore’s contentious “proof of the existence of a material world” in not cogent because no warrant can transmit from its premise to its conclusion. Since Bayesian confirmation theory probably affords the best account of inductive reasoning we have today, if Wright’s analysis of Moore’s “proof” could be translated in Bayesian language, it would probably be preferable to rival analyses that cannot be reformulated in the same way. Okasha has recently proposed a Bayesian model that apparently vindicates Wright’s analysis on the whole. In this paper I first argue that Okasha’s Bayesian vindication is in different respects flawed and thus unacceptable. I then propose a more suitable Bayesian framework, resting on the so-called Lockean Thesis, which does vindicate Wright’s analysis. My investigation sheds new lights on the logical features proper to the warrant that Wright deems not to transmit across entailment, on the constituents of the logical “mechanism” that according to Wright engenders failure of transmission, and on the fine structure of the rational architecture of perceptual warrant outlined by Wright.
Liberals claim that some perceptual experiences give us immediate justification for certain perceptual beliefs. Conservatives claim that the justification that perceptual experiences give us for those perceptual beliefs is mediated by our background beliefs. In his recent paper 'Basic Justification and the Moorean Response to the Skeptic', Nico Silins successfully argues for a non-Moorean version of Liberalism. But Silins's defence of non-Moorean Liberalism leaves us with a puzzle: why is it that a necessary condition for our perceptual experiences to justify us in holding certain perceptual beliefs is that we have some independent justification for disbelieving various sceptical hypotheses? I argue that the best answer to this question involves commitment to Crispin Wright's version of Conservatism. In short, Wright's Conservatism is consistent with Silins's Liberalism, and the latter helps to give us grounds for accepting the former.
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.
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'.
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.
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.
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.
A series of unnoticeably small changes in an observable property may add up to a noticeable change. Crispin Wright has used this fact to prove that perceptual indiscriminability is a non-transitive relation. Delia Graff has recently argued that there is a 'tension' between Wright's assumptions. But Graff has misunderstood one of these, that 'phenomenal continua' are possible; and the other, that our powers of discrimination are finite, is sound. If the first assumption is properly understood, it is not in tension with but is actually implied by the second, given a plausible physical assumption.
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