David R. Hilbert

When we open our eyes, the world seems full of colored opaque objects, light sources, and transparent volumes. One historically popular view, _eliminativism_, is that the world is not in this respect as it appears to be: nothing has any color. Color _realism_, the denial of eliminativism, comes in three mutually exclusive varieties, which may be taken to exhaust the space of plausible realist theories. Acccording to _dispositionalism_, colors are _psychological_ dispositions: dispositions to produce certain kinds of visual experiences. According to both _primitivism_ and _physicalism_, colors are not psychological dispositions; they differ in that primitivism says that no reductive analysis of the colors is possible, whereas physicalism says that they are physical properties. This paper is a defense of physicalism about color

What is color? Of course, examples of colorful objects are not hard to come by (Fig. 1 provides numerous examples), so the question itself is slightly puzzling, suggesting that some confusion needs to be cleared up or ignorance enlightened. But how could anyone (who isn’t blind or Fig. 1 Atoms Inside Balloons totally lacking in color vision) possibly be confused about what color is? After all, if we learn anything about the world merely by looking at it, it’s the colors of the things we see. How could we do this if we were confused about or ignorant of the nature of color? We might be confused..

The 18th century philosopher and Anglican bishop, George Berkeley, is chiefly known to posterity for advocating the radical thesis that there is no unthinking stuff in the world. According to Berkeley, bar stools, kegs, mugs and the all paraphernalia of ordinary life (plus everything else) are merely ideas and have no existence outside the mind of those seated on the stools, tapping the kegs, and drinking from the mugs. What is less well-known is that Berkeley devoted much of his energy in later life to promoting the use of a concoction he called tar-water for the treatment of a wide variety of health ailments. Fortunately, Berkeley thought that many of the same virtues were found in some beers. It may seem paradoxical that one and the same man could both claim that beer only exists as an idea in the minds of those consuming it and that it could cure all known afflictions. Berkeley's resolution of this paradox will be explored and it will be seen that it is possible to both appreciate and benefit from beer even if it is only an idea.

Colour has often been supposed to be a subjective property, a property to be analysed orretly in terms of the phenomenological aspects of human expereince. In contrast with subjectivism, an objectivist analysis of color takes color to be a property objects possess in themselves, independently of the character of human perceptual expereince. David Hilbert defends a form of objectivism that identifies color with a physical property of surfaces - their spectral reflectance. This analysis of color is shown to provide a more adequate account of the features of human color vision than its subjectivist rivals. The author's account of colro also recognises that the human perceptual system provides a limited and idiosyncratic picture of the world. These limitations are shown to be consistent with a realist account of colour and to provide the necessary tools for giving an analysis of common sense knowledge of color phenomena.

The Dangerous Book for Boys Abstract: Seventeenth and eighteenth century discussions of the senses are often thought to contain a profound truth: some perceptible properties are secondary qualities, dispositions to produce certain sorts of experiences in perceivers. In particular, colors are secondary qualities: for example, an object is green iff it is disposed to look green to standard perceivers in standard conditions. After rebutting Boghossian and Velleman’s argument that a certain kind of secondary quality theory is viciously circular, we discuss three main lines of argument for the secondary quality theory. The first is inspired by an intuitively compelling picture of perception articulated by Reid; the second is that the secondary quality theory is a conceptual truth; the third line of argument is presented in Johnston’s influential paper ‘How to speak of the colors’. We conclude that all these arguments fail, and that the secondary quality theory is unmotivated. Keywords: color, secondary quality, disposition, vision, perception..

Larry Hardin has been the most steadfast and influential critic of physicalist theories of color over the last 20 years. In their modern form these theories originated with the work of Smart and Armstrong in the 1960s and 1970s1 and Hardin appropriately concentrated on their views in his initial critique of physicalism.2 In his most recent contribution to this project3 he attacks Michael Tye’s recent attempts to defend and extend color physicalism.4 Like Byrne and Hilbert5, Tye identifies color with the reflecting properties of objects (“reflectance physicalism”). Specifically, the determinate and determinable colors are identified with types of reflectances. (Setting some complications aside, the reflectance of an object is the proportion of light that it reflects at each wavelength in the visible spectrum.) These reflectance types are, in the terminology of Hilbert, anthropocentric—in the terminology of Lewis6, they are not very “natural”.

Naturalistic theories of content and whether or not reason-giving explanations of human behavior are causal explanations have been central topics in recent philosophy of mind. Fred Dretske, in his book Explaining Behavior, attempts to construct a naturalistic theory of the contents of beliefs and desires that gives these mental states an important role in the causation of behavior. Even if Dretske is granted that the theory adequately accounts for individual behaviors the theory still faces problems in offering an adequate account of important features of extended sequences of behavior. Some sequences of behavior exhibit coherence in the sense that the elements of the sequence either contribute to the atttainment of a goal state or only make sense on the supposition that the goal state will be attained. Two ways of attaining coherence are distinguished. In chaining behavior coherence is guaranteed by the fit between the internal structure of the organism and the structure of the external environment. In other cases of coherence chaining is not available as an explanation. It is argued that Dretske.

The target article is an attempt to make some progress on the problem of color realism. Are objects colored? And what is the nature of the color properties? We defend the view that physical objects (for instance, tomatoes, radishes, and rubies) are colored, and that colors are physical properties, specifically types of reflectance. This is probably a minority opinion, at least among color scientists. Textbooks frequently claim that physical objects are not colored, and that the colors are "subjective" or "in the mind." The article has two other purposes: first, to introduce an interdisciplinary audience to some distinctively philosophical tools that are useful in tackling the problem of color realism and, second, to clarify the various positions and central arguments in the debate.

Deeply original, inspiring to some, abhorrent to others, George Berkeley’s philosophy of immaterialism is still influential three hundred years after the publication of his most widely read book, _Three Dialogues Between Hylas and Philonous. _Berkeley published the _Dialogues _because of the unenthusiastic reception of his _Principles of Human Knowledge _in 1710._ _He hoped the use of the_ _dialogue format would win a more favorable hearing, but unfortunately for Berkeley, the response was every bit as scathing as the reception of his previous work. In recent decades, Berkeley’s work has been recognized as an excellent introduction to the English philosophy of the eighteenth century, and to philosophy in general. This edition of the dialogues is accessibly organized by David Hilbert and John Perry.

Anomaloscope An instrument used for detecting anomalies of color vision. The test subject adjusts the ratio of two monochromatic lights to form a match with a third monochromatic light. The most common form of this procedure involves a Rayleigh match: a match between a mixture of monochromatic green and red lights, and a monochromatic yellow light. Normal subjects will choose a matching ratio of red to green light that falls within a fairly narrow range of values. Subjects with anomalous color vision will choose a ratio of red to green that falls outside this range, and red-green dichromats will accept any ratio of red to green as forming a match

There are serious reasons for accepting each of these propositions individually but there are apparently insurmountable difficulties with accepting all three of them simultaneously if we assume that color is a single property. 1) and 2) together seem to imply that there is some property which all organisms with color vision can see and 3) seems to imply that there can be no such property. If these implications really are valid then one or more of these propositions will have to be rejected in spite of whatever reasons can be given for their apparent acceptability. Before going on to discuss possible resolutions of this apparent contradiction it is worth pointing out there our three propositions are not all of a kind. Proposition 1) is a metaphysical thesis about the ontological status of color and proposition 3) is an empirical thesis about what properties organisms with color vision are capable of detecting. If you accept 1) then 2) will appear to verge on the trivial, but if 1) is denied then the status of 2) will appear more problematic. In what follows I will have more to say about why we either should or should not accept all three of these propositions.

One of the traditional problems of philosophy is the nature of the connection between perceptual experience and empirical knowledge. That there is an intimate connection between the two is rarely doubted. Three case studies of visual deficits due to brain damage are used to motivate the claim that perceptual experience is neither necessary nor sufficient for perceptual knowledge. Acceptance of this claim leaves a mystery as to the epistemic role, if any, of perceptual experience. It is argued that one function of perceptual experience is to provide information about the sources of beliefs, both as to which perceptual modality and within a given modality. This information is useful in assessing the reliability of perceptual beliefs.

In Colour for Architecture, published in 1976, the editors, Tom Porter and Byron Mikellides, explain that their book was “produced out of an awareness that colour, as a basic and vital force, is lacking from the built environment and that our knowledge of it is isolated and limited.”1 Lack of urban color was then especially salient in Britain—where the book was published—which had just begun to recoil at the Brutalist legacy of angular stained gray concrete strewn across the postwar landscape. Perhaps because the most urgent need was to inject some hue into this architectural dystopia, one of the main innovations illustrated in the book involves nothing more than cans of paint. Dull unfinished concrete façades, the interior of a subway station, a cement works, and so on, are shown enlivened by fields of bright color.

Color-vision defects constitute a spectrum of disorders with varying degrees and types of departure from normal human color vision. One form of color-vision defect is dichromacy; by mixing together only two lights, the dichromat can match any light, unlike normal trichromatic humans, who need to mix three. In a philosophical context, our titular question may be taken in two ways. First, it can be taken at face value as a question about visible properties of external objects, and second, it may be interpreted as the more intangible question of “what it’s like” to be color-blind.