Where are we to look for the unique hues? Out in the world? In the eye? In more central processing? 1. There are difficulties looking for the structure of the unique hues in simple combinations of cone-response functions like ( L − M ) and ( S − ( L + M )): such functions may fit pretty well the early physiological processing, but they don’t correspond to the structure of unique hues. It may seem more promising to look to, (...) e.g., Hurvich & Jameson’s ‘chromatic response functions’; but these report on psychophysical behaviour, not on underlying physiology. So ‘opponent processing’ isn’t any particular help on the unique hues—and even physiology in general seems not to have come up with any good correlate or explanation. 2. Wright ( Review of Philosophy and Psychology 2: 1–17, 2011 ) looks in a different place: to (a) magnitude of total visual response that a stimulus light provokes, the maxima and minima of which, he thinks, give us the boundaries of the main hue categories (Wright connects these with Thornton’s ‘prime’ and ‘antiprime’ colours in an illuminant: Journal of the Optical Society of America 61 ( 1971 ): 1155–1163); and (b) the ratio of chromatic to achromatic response, the maxima and minima of which, he suggests, give us the focal points of the unique hues. The suggestions are extremely interesting; but the desired correspondences have some counterexamples; and where they hold, one could wonder how much they depend upon the particular choice of functions to measure (a) and (b); and one could hope for more of an explanatory linkage between the sets of items in question. 3. Could the unique hues come from, so to speak, the external world? White and black can easily be defined as particular kinds of reflectance. What of the standard four unique hues? Variation in kinds of sunlight and skylight coincides well with variation along a line from unique yellow to unique blue (cf. Shepard 1992 , Mollon 2006 ). If we wanted something to calibrate our standards for unique yellow and blue as the lens of the eye changes with age, and despite interpersonal cone differences, this would be a good basis—and there are several ways this can be extended to surface colours. But is there any essential connection between these things: is there any rationale why the light of the sun and the sky should be counted as unique hued ? An answer may be: because in our environment, these illuminants are as close to white (or the natural illuminant colour) as you can get—to see things tinged with sunlight or skylight should be to see them minimally tinged with any alien colour. Whereas other hues in an illuminant would be treated as tinging with a more alien colour the thing seen. (shrink)
To the familiar idea of an undetectable spectrum inversion some have added the idea of inverted earth. This new combination of ideas is even harder to make coherent, particularly as it applies to a supposed inversion of black and white counteracted by an environmental switch of these. Black and white exhibit asymmetries in their connections with illumination, shadow and visibility, which rule out their being reversed. And since the most saturated yellow is light and the most saturated blue dark, yellow (...) and blue could not be reversed unless light and dark could be. The difficulties suggest some more general morals for how to think of the role of 'qualia' in colour perception. (shrink)
Barry Stroud’s book _The Quest for Reality_1 is, I think, the most substantial study of colour realism that has yet been written. It subjects to fundamental criticism a tradition that found its classic expression in Descartes and Locke and which in many ways remains standard today; it argues to be flawed not only the traditional rejection of colours as mere ideas or features of ideas in the mind, but also the view that colours are dispositions or powers in objects to (...) produce ideas in us—which in other quarters sometimes passes as a form of colour realism. Stroud rejects subjectivism, dispositionalism, relativism, and reductionism; but he is deliberately reticent about offering any positive account of what we believe to exist when believe colours to exist (after all, he says, in quiet allusion to Butler, everything is what it is and not another thing). And he is resolute in denying that we can give a philosophical argument to establish such belief as true. Stroud’s general conclusion can be seen as occupying a middle ground between what we might call dogmatic anti-realism and dogmatic realism. He argues (in Ch. 7) that anti-realism (or what Stroud calls the ‘unmasking’ of colours) is a view that cannot be affirmed without a kind of self-refutation—for ‘no one could abandon all beliefs about the colours of things and still _understand_ the colour terms’ (168, my emphasis). On the other hand (in Ch. 9), it remains in some sense a ‘possibility’ (204) that everyday colour beliefs might actually all be false. Stroud’s final judgment is not that we shall or should abandon the ‘Quest for Reality’, though he has expressed many reservations about it.2 The. (shrink)
The categorial concepts of substance (thing) and substance (stuff) are described, and the conceptual relationships between things and their constitutive stuff delineated. The relationship between substance concepts, expressed by other count-nouns, and natural kind concepts is examined. Artefacts and their parts are argued to be substances, whereas parts of organisms are not. The confusions of seventeenth- and eighteenth-century philosophers who invoked the concept of substance are adumbrated.
Byrne & Hilbert (B&H) give some excellent replies to the objections to realism about color. However, the particular form of realism they propose, based on opponent processing, prompts several challenges. Why characterize a color by its tendency to produce an intermediate brain signal, rather than in terms of the final effect – either a perception or a neural substrate for it? At the level of the retina, and even of the cortex, there are processes that partly parallel the structure of (...) color experience; but the correspondence is not exact. Must we assume that there is any place in the brain where an exact structural correspondence is found? At the level of psychophysical functioning, there is indeed opponency; but it is not clear that this gives us the kind of type-reduction that B&H want. (shrink)
O'Regan & Noë make plausible that perception involves mastery of sensory-motor dependencies. Their rejection of qualia, however, is less persuasive; as is their view that we see only what we are attending to. At times they seem to oppose “internal representation” in general; I argue that they should in fact only be rejecting crude conceptions of brain picturing.
In The Secret Connexion1 Galen Strawson argues against the traditional interpretation of Hume, according to which Hume’s theory of meaning leads him to a regularity theory of causation. In actual fact, says Strawson, ‘Hume believes firmly in some sort of natural necessity’ (p. 277). What Hume denied was that we are aware of causal connections outrunning regular succession, and that we have a ‘positively or descriptively contentful conception’ of such powers (p. 283); he did not deny that there are such (...) powers, or that they are what we are talking about when we talk about causation. Strawson has four central lines of argument. His ‘most direct evidence’ (p. 2) against a regularity interpretation consists of (1) passages where Hume refers to hidden powers underlying the regularities of which we are aware. Strawson’s broader motivations for rejecting the traditional interpretation are (2) that the regularity theory is in itself quite absurd, and (3) that it is incompatible with Hume’s ‘non-committal scepticism’. And the method which he uses to defend his interpretation against pressure from the theory of ideas is (4) to develop some comments of Hume’s on ‘relative’ ideas into something like a further theory of content to supplement the theory of ideas. Strawson develops almost the strongest case I can imagine for his claims. I shall try to explain why he leaves me unconvinced. (shrink)
This essay* takes two notions of autonomy and two notions of explanation and argues that colours occur in explanations that fall under all of them. The claim that colours can be used to explain anything at all may seem to some people an outrage. But their pessimism is unjustified and the orthodox dispositional view which may seem to support it, I shall argue, itself has difficulties. In broad terms, Section 2 shows that there exist good straight scientific laws of colour, (...) constituting what one might call a phenomenal science. Section 3 offers a larger view of what we are doing when we attribute colours to things, a view which makes it a case of holistic explanation, similar in many ways to psychological explanation. Section 2 emphasizes the model of scientific explanation, and Section 3 the holistic model found in rational explanation; but it will emerge that colour explanation in different ways fits both models, as it also does the two principal notions of autonomy that the first section identifies. (shrink)