David R. Hilbert

Philosophers have devoted a great deal of discussion to the question of whether an inverted spectrum thought experiment refutes functionalism. (For a review of the inverted spectrum and its many philosophical applications, see Byrne, 2004.) If Ho?man is correct the matter can be swiftly and conclusively settled, without appeal to any empirical data about color vision (or anything else). Assuming only that color experiences and functional relations can be mathematically represented, a simple mathematical result.

A sensible quality is a perceptible property, a property that physical objects (or events) perceptually appear to have. Thus smells, tastes, colors and shapes are sensible qualities. An egg, for example, may smell rotten, taste sour, and look cream and round.1,2 The sensible qualities are not a miscellanous jumble—they form complex structures. Crimson, magenta, and chartreuse are not merely three different shades of color: the first two are more similar than either is to the third. Familiar color spaces or color solids capture, to a greater or lesser extent, these relations between the colors. The same goes for sensible qualities perceived in other modalities: middle C, high C, and D are not merely three different notes, and the taste of lemons, oranges, and sugar cubes are not merely three different tastes. How can this structure of appearance be explained? One idea is that sensible qualities are of two sorts: basic and derived. The basic sensible qualities are the building blocks from which the derived sensible qualities can be..

Perception and thought are often, although not exclusively, concerned with information about the world. In the case of perceiving though, unlike thinking, it is widely believed that there is an additional element involved, a subjective feeling or, as it is often put, something that it is like to be perceiving. Qualia are these characteristic feelings that accompany perceiving. One motivation for the idea that we experience qualia is that there is a clear difference between seeing a red tomato and thinking that a tomato is red and that the difference has to do with some extra element present in the case of seeing that is absent in the case of thinking. Philosophical attempts to understand qualia and their place in the world have played a central role in recent debates about the nature of mind and its place in the world. Before getting to those debates, we will take a more detailed look at the distinction between the content of perceptual experiences,what they tell us about the world, and their qualitative or phenomenal character, what it is like to experience them.

The typical kind of color realism is reductive: the color properties are identified with properties specified in other terms (as ways of altering light, for instance). If no reductive analysis is available — if the colors are primitive sui generis properties — this is often taken to be a convincing argument for eliminativism. That is, realist primitivism is usually thought to be untenable. The realist preference for reductive theories of color over the last few decades is particularly striking in light of the generally anti-reductionist mood of recent philosophy of mind. The parallels between the mind—body problem and the case of color are substantial enough that the difference in trajectory is surprising. While dualism and non-reductive physicalism are staples, realist primitivism is by and large a recent addition to the color literature. And it remains a minority position, although one that is perhaps gaining support. In this paper, we investigate whether it should be accepted, and conclude it should not be

The world as perceived by human beings is full of colour. The world as described by physical scientists is composed of colourless particles and fields. Philosophical theories of colour since the scientific revolution have been primarily driven by a desire to harmonize these two apparently conflicting pictures of the world. Any adequate theory of colour has to be consistent with the characteristics of colour as perceived without contradicting the deliverances of the physical sciences. Given this conception of the aim of a theory of colour, there are three possibilities for resolving the apparent conflict between the scientific and perceptual facts. The first possibility is to deny that physical objects have colours. Theories of this kind admit that objects appear coloured but maintain that these appearances are misleading. The conflict is resolved by removing colour from the external world. Second, it might be that colour is a relational property. For an object to possess a particular colour it must be related in the right way to a perceiver. One common version of this view analyzes colour as a disposition to cause particular kinds of perceptual experiences in a human being. Since the physical sciences deal only with the intrinsic properties of physical objects and their relations to other physical objects and not their relations to perceiving subjects, the possibility of conflict is removed. A third possible response to the conflict is to maintain that colour really is a property of external objects and that the conflict is merely apparent. Some theories of this form maintain that colour is identical to a physical property of objects. Others maintain that colour is a property that physical objects possess over and above all their physical <blockquote> 1 </blockquote> properties. Philosophical discussions of colour typically take the form of either elaborating on one of these three possibilities or attempting to show more generally that one of these three types of responses is to be preferred to the others..

Although it has been something of a fetish for philosophers to distinguish between hallucination and illusion, the enduring problems for philosophy of perception that both phenomena present are not essentially different. Hallucination, in its pure philosophical form, is just another example of the philosopher’s penchant for considering extreme and extremely idealized cases in order to understand the ordinary. The problem that has driven much philosophical thinking about perception is the problem of how to reconcile our evident direct perceptual contact with objects and properties with the equally evident fact that there is no phenomenological signal separating error and truth. “The obscure object of hallucination” offers a subtle and plausible solution to this problem and one that solves the problem generally, not just in the special case of hallucination. Johnston’s objective is to offer a theory of perception that meets two constraints: (1) that it provide an explanation of the possibility of delusive and veridical sensings that are indistinguishable from the first-person perspective and (2) that it count as form of direct realism where this is taken to involve acquaintance with the objects of perception. Johnston uses the first constraint to rule out disjunctivism. The second constraint is used to rule out conjunctivism, which as Johnston uses the term, includes most of the widely adopted philosophical theories of perception. Johnston also develops his own sophisticated and interesting theory of perception. In what follows, I will discuss the relation of Johnston’s theory to conjunctivism, examine one of his anti-conjunctivist arguments and finally compare Johnston’s theory with some other versions of direct realism. These topics constitute a very incomplete selection of the important issues discussed in this rich and interesting paper. I will also not disagree, in any fundamental way, with any of the central theses of Johnston’s discussion..

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”.