Reflectance realism is an important position in the philosophy of colour. This paper is an examination of David R. Hilbert’s case for there being scientific support for the theory. The specific point in question is whether colour science has shown that reflectance is recovered by the human visual system. Following a discussion of possible counter-evidence in the recent scientific literature, I make the argument that conflicting interpretations of the data on reflectance recovery are informed by different theoretical assumptions about the (...) nature of
colour, and of perception. If this is so, there cannot be neutral empirical
evidence on this point, and this does seem to undermine Hilbert’s claim for
empirical support. In the end, I suggest alternative ways of thinking about the relationship between colour ontology and empirical work on colour. (shrink)

The authors favor a “color realism” theory that considers colors to be physical properties residing in objects that reflect, emit, or transmit light. It is opposed to the theory that colors are sensations or visual experiences. This commentary suggests that both theories are correct, and that context usually indicates which of these dual aspects is being considered.

The reflectance types that Byrne & Hilbert identify with colors count as types only in a way that is more dependent on, and more relative to color perceivers, than their account suggests. Their account of perceptual content may be overly focused on input conditions and distal causes.

While color realism is endorsed, Byrne & Hilbert's (B&H's) case for it stretches the notion of “physical property” beyond acceptable bounds. It is argued that a satisfactory account of color should do much more to respond to antirealist intuitions that flow from the specificity of color experience, and a pointer to an approach that does so is provided.

Byrne & Hilbert are right that it might be an objective fact that a particular tomato is unique red, but wrong that it cannot simultaneously be yellowish-red (not only objectively, but from somebody else's point of view). Sensory categorization varies among organisms, slightly among conspecifics, and sharply across taxa. There is no question of truth or falsity concerning choice of categories, only of utility and disutility. The appropriate framework for color categories is Nominalism and Pluralistic Realism.

Reflectance and spectral power functions are poor predictors of color experiences. Only in completely relativized conditions (single observer, non-metameric set of stimuli, and single set of viewing conditions) is the relationship close. Variation in reflectance of Munsell chips experienced by color-normal observers as having a unique green hue encompasses approximately sixty percent of the complete range of hues falling under the category “green”; and in recent determinations of unique hues, ranges of yellow and green as well as green and blue (...) unique hues overlap. (shrink)

There are 2,000 hair cells in the cochlea, but only three cones in the retina. This disparity can be understood in terms of the differences between the physical characteristics of the auditory signal (discrete excitations and resonances requiring many narrowly tuned receptors) and those of the visual signal (smooth daylight excitations and reflectances requiring only a few broadly tuned receptors). We argue that this match supports the physicalism of color and timbre.

Metamerism is a rather common feature of objects. The authors see it as problematic because they are concerned with a special case: metamerism in standard conditions. Such metamerism does not, however, pose a problem for color realists. There is an apparent problem in cases of metameric light sources, but to see such metamers as problematic is to fail to answer Berkeley's challenge.

Reflectance physicalism only provides a partial picture of the ontology of color. Byrne & Hilbert’ account is unsatisfactory because the replacement of reflectance functions by productance functions is ad hoc, unclear, and only leads to new problems. Furthermore, the effects of color contrast and differences in illumination are not really taken seriously: Too many “real” colors are tacitly dismissed as illusory, and this for arbitrary reasons. We claim that there cannot be an all-embracing ontology for color.

The problem of nonreflectors perceived as colored is the central problem for Byrne & Hilbert's (B&H's) physicalism. Vision scientists and other interested parties need to consider the motivation for their account of “productance physicalism.” Is B&H's theory motivated by scientific concerns or by philosophical interests intended to preserve a physicalist account of color as a posteriori necessary?

We argue that any theory of color physicalism must include consideration of ecological interactions. Ecological and sensorimotor contingencies resulting from relative surface motion and observer motion give rise to measurable effects on the spectrum of light reflecting from surfaces. These contingencies define invariant manifolds in a sensory-spatial space, which is the physical underpinning of all subjective color experiences.

Byrne & Hilbert (B&H) assert that reflectances embody the reality of color, but metamerism smears the authors' “real” color categories into uselessness. B&H ignore this problem, possibly because they implicitly adopt a sort of subjectivism, whereby an object is defined by the percepts (or more generally by the measurements) it engenders. Subjectivism is unwieldy, and hence prone to such troubles.

To identify the set of reflectances that constitute redness, the authors must first determine which surfaces are red. They do this by relying on widespread agreement among us. However, arguments based on the possible ways in which humans would perceive colors show that mere widespread agreement among us is not a satisfactory way to determine which surfaces are red.

The primary issues concern whether objects have colours, and what sorts of properties the colours are. Some philosophers hold that nothing is coloured, others that colour are powers to affect perceivers, and others that colours are physical properties.

Supervaluationism, traditionally conceived, is the conjunction of three theses: Vagueness in a language gives rise to there being a multitude of acceptable assignments of semantic values to some expressions of the language, These assignments correspond to possible completions of the meanings of vague expressions, Truth is truth under all acceptable assignments, and falsity is falsity under all acceptable assignments. Supervaluationism has three chief virtues. It preserves classical logic. It provides an account of what vagueness is . And it extends nicely (...) to the vagueness of singular terms. I argue, however, that the existence of vagueifiers ‐ expressions like‘roughly’– pose problems for thesis of Supervaluationism, and that the supervaluationist can get around these problems only at a serious cost. Toward the end of the paper, I present an alternative analysis of vagueness, which preserves the main virtues of Supervaluationism, but which identifies vagueness as semantic Overdetermination, rather than as semantic underdetermination. (shrink)

When objects are illuminated, the light they reflect does not simply bounce off their surface. Rather, that light is entirely reabsorbed and then reemitted, as the result of a complex microphysical event near the surface of the object. If we are to be physicalists regarding color, then we should analyze colors in terms of that event, just as we analyze heat in terms of molecular motion, and sound in terms of vibrations. On this account, colors are not standing properties of (...) objects, but events, or (more cautiously) properties associated with events. Accordingly, objects in the dark are no more colored than a turned-off stove is hot. Such an account requires rejecting some of what folk ordinarily say about color, but this is the most coherent version of color physicalism. (shrink)

Russell and others have argued that the real nature of colour is transparentto us in colour vision. It's nature is fully revealed to us and no further knowledgeis theoretically possible. This is the doctrine of revelation. Two-dimensionalFourier analyses of coloured checkerboards have shown that apparently simple,monadic, colours can be based on quite different physical mechanisms. Experimentswith the McCollough effect on different types of checkerboards have shown thatidentical colours can have energy at the quite different orientations of Fourierharmonic components but no (...) energy at the edges of the checkerboards, thusrefuting revelation. It is concluded that this effect is not explained by a superveniencedispositional account of colour as proposed by McGinn . It was argued that theMcCollough effect in checkerboards was an example of a local mind/body reduction, by which the different characteristics of identical colours falsifies revelation. This reduction being based on both physical and neurological mechanisms led to a clear explanation of the perceive phenomenal effects and thus laid a small bridge over the explanatory gap. (shrink)

The nature of color is an open philosophical and scientific question. In this work I develop a physicalist relationist theory of color. So far, attempts to identify color as a physical property of objects have not been convincing because no physical property used by scientists seems to be well correlated with color sensations. I define a new physical property which I call transformance and show that transformance is 100% correlated with color sensations. Intuitively, transformance is a very general abstract physical (...) property that describes how a system transforms or modifies light or information that characterizes light. It turns out that transformance is a relational property of objects like velocity and weight. Transformance is related to surface reflectance as weight is related to mass. Transformance is a much better candidate to be color than surface reflectance because it is 100% correlated with color sensations, precisely models surround effects and fully explains all issues that relate to perceptual variation or the lack thereof. Several concrete examples are provided that show how the transformance of different systems should be modeled. After defining transformance, I defend the theory that color is transformance against possible objections while contrasting my theory with the theory that color is surface reflectance. I then discuss the relations between color and color sensation and the more general objections to any physicalist theory of color. The final part of the thesis deals with epistemological issues related to my theory of color including two apparent paradoxes that I believe every theory of color must answer: 1) How is it that human beings get along so well with an erroneous theory of color? 2) How can science, which is based on the common sense theory of color, conclude that the common sense theory is wrong? I show that my theory provides answers to these questions. (shrink)

Byrne & Hilbert defend color realism, which assumes that: (a) colors are properties of objects; (b) these objects are physical; hence, (c) colors are physical properties. I accept (a), agree that in a certain sense (b) can be defended, but reject (c). Colors are properties of perceptual objects – which also have underlying physical properties – but they are not physical properties.

This paper develops and defends the view that substantively normative uses of words like “good”, “right” and “ought” are irresolvably indeterminate: any single case of application is like a borderline case for a vague or indeterminate term, in that the meaning-fixing facts, together with the non-linguistic facts, fail to determine a truth-value for the target sentence in context. Normative claims, like vague or indeterminate borderline claims, are not meaningless, though. By making them, the speaker communicates information about the precisifications that (...) s/he accepts. The analogy with vague/indeterminate language, I argue, lays out a new and interesting foundation for a subjectivist approach to normativity. (shrink)

Byrne & Hilbert defend color realism, which assumes that: (a) colors are properties of objects; (b) these objects are physical; hence, (c) colors are physical properties. I accept (a), agree that in a certain sense (b) can be defended, but reject (c). Colors are properties of perceptual objects – which also have underlying physical properties – but they are not physical properties.

How could perceptual experiences reveal matters of essentiality? Answering this question is crucial for vindicating a thesis about the epistemic import of experience, commonly known as Revelation. The thesis comes in a weak and a strong version. Only on the strong one could it make up an authoritative piece of common sense. But this version also seems to demand too much of our experiences, namely that they can reveal essentiality. However, the impression that our experiences are not suited for this (...) turns out to be due to a non-mandatory assumption about how the revelation of essentiality would work. (shrink)

This entry outlines physicalism about color, and objections to the effect that it cannot meet various desiderata on a metaphysics of color.

The question of the constituting nature of colour is largely open. The old dispute between colour objectivism and colour subjectivism is still relevant. The former has defended itself against accusations of not being able to explain colour structures, while the latter view has received criticism for not being able to provide a plausible theory of the location of colours. By weakening the notion of physical categories, making some of them perceiver-depended, colour objectivists have managed to overcome at least some of (...) the previous accusations. However, the arguments based on Crane’s and Piantanida’s findings of the existence of binary colours like greenish-red and yellowish-blue, indicate the inadequacy of colour objectivism. Consequently, we have colours but our theories of them are false. (shrink)

1 Introduzione Quando i filosofi fanno affermazioni del tipo “gli A sono finzioni”, il più delle volte ciò che dicono è ambiguo in un modo cruciale. Secondo una certa lettura, ciò che viene detto ha chiare implicazioni ontologiche: non ci sono, in realtà, cose come gli F. Ma c’è anche un modo diverso, non ontologico, di leggere tali affermazioni: come se dicessero semplicemente che le A-asserzioni sono avanzate, di norma, in uno spirito finzionale. Chiaramente, si può sostenere che normalment...

I1. Anil Gupta distinguishes between thin and thick experiences. There are thick experiences like, say, the American Experience of a European traveller. And thin experiences like looking at a yello...

Our reading is a passage from John Locke, An Essay Concerning Human Understanding , Book III, Chapter II, § 2. When a man speaks to another, it is that he may be understood; and the end of speech is that those sounds, as marks, may make known his ideas to the hearer. … Words being voluntary signs, they cannot be voluntary signs imposed by him on things he knows not. That would be to make them signs of nothing, sounds without (...) signification. (shrink)

In this commentary I argue that Byrne & Hilbert commit a number of philosophical solecisms: They beg the question of “realism,” they take the phenomenon and the theoretical model to be the same thing, and they surreptitiously substitute data sets for the life-world.

Visual percepts are called veridical when a “real” object can be identified as their cause, and illusions otherwise. The perceived position and color of a flashed object may be called veridical or illusory depending on which viewpoint one adopts. Since “reality” is assumed to be fixed (independent of viewpoint) in the definition of veridicality (or illusion), this suggests that “perceived” position and color are not properties of “real” objects.

Byrne & Hilbert propose that color can be identified with explicit properties of physical surfaces. I argue that this claim must be qualified to take into account constraints needed to make recovery of surface color information possible. When these constraints are satisfied, then a biological visual system can establish a correspondence between perceived surface color and specific surface properties.

For all animals, color is an indicator of the substance and state of objects, for which purpose reflectance is just one among many relevant optical properties. This broader meaning of color is confirmed by linguistic evidence. Rather than reducing color to a simple physical property, it is more realistic to embrace its full phenomenology.