There exist two widely used notions concerning the structure of phenomenal color space. The first is the notion of unique/binary hue structure, which maintains that there are four unique hues from which all other hues are composed. The second notion is the similarity structure of hues, which describes the interrelations between the hues and hence does not divide hues into two types as the first notion does. Philosophers have considered the existence of the unique/binary hue structure to be empirically and (...) phenomenally well-grounded, and the structure has been considered to be primary because this can account for the similarity structure. Consequently, the unique/binary hue structure has played a central role in color philosophy. This calls for the assessment of the justification for its existence carried out in this paper. It is concluded that, despite the prevalent view among philosophers, none of their reasons for endorsing the existence of the unique/binary hue structure are justified. Since the notion of the unique/binary hue structure appears intuitively plausible for many, however, a sketch explaining this intuition is outlined at the end. (shrink)

Colour vision plays a foundational explanatory role in the philosophy of colour, and serves as perennial quarry in the wider philosophy of perception. I present two contributions to our understanding of this notion. The first is to develop a constitutive approach to characterizing colour vision. This approach seeks to comprehend the nature of colour vision qua psychological kind, as contrasted with traditional experiential approaches, which prioritize descriptions of our ordinary visual experience of colour. The second contribution is to argue that (...) colour vision does not constitutively involve the ability to see colours, in a natural and categorically committed sense. I argue that two subjects exactly alike in respect of their constitutive colour vision abilities could differ in respect of whether or not they have categorical perception of colour. The argument is supported by thought experiment and dissociations observed in cognitive neuropsychology. The argument also bears connections to recent neo-Whorfian accounts of colour categorization. _1._ Introduction _2._ Colour Vision, Experience, and Natures _3._ The Central Argument _3.1._ Colour constancy and discrimination _3.2._ Dissociating colour vision and categorical perception for colour _4._ Whorf and the View from Cognitive Neuropsychology _5._ Conclusion. (shrink)

In this chapter, I critically examine two of the main approaches to colour categorization in cognitive science: the perceptual salience theory and linguistic relativism. I then turn to reviewing several decades of psychological research on colour categorical perception (CP). A careful assessment of relevant findings suggests that most of the experimental effects that have been understood in terms of CP actually fall on the cognition side of the perception-cognition divide: they are effects of colour language, for example, on memory or (...) decision-making. (shrink)

As demonstrated by several example displays, color illusions challenge color realism, because they involve a one-to-many reflectance-to-color mapping. Solving this problem by differentiating between veridical and illusory colors corresponding to the same reflectance is hampered because of the lack of an appropriate criterion. However, the difference between veridical and illusory color perception can still be maintained.

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.

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. (shrink)

A version of the inverted spectrum thought experiment that disconfirms functionalism for the case of humans’ color experiences has typically been thought to require a certain kind of balancing act. What one needs, it has typically been thought, is a mapping of color experiences onto other color experiences that preserves the similarity and difference relationships among those experiences and the aspects of perceived colors underlying those similarities and differences. However, there are good reasons for being suspicious about whether that is (...) possible when the palette of color experiences is that available to humans with normal vision. The new version of the thought experiment constructed here doesn’t depend on preserving those relationships. I argue that there is a coherent, metaphysically possible scenario in which two human color experiences—any two—can be seen to be functionally equivalent. The upshot is that functionalism fails for all human color experiences. (shrink)

Can we maintain that purple seems composed of red and blue without giving up the impenetrability of the red and blue parts that compose it? Brentano thinks we can. Purple, according to him, is a chessboard of red and blue tiles which, although individually too small to be perceived, are together indistinctly perceived within the purple. After a presentation of Brentano’s solution, we raise two objections to it. First, Brentano’s solution commits him to unperceivable intentional objects (the chessboard’s tiles). Second, (...) his chessboard account fails in the end to explain the phenomenal spatial continuity of compound colours. We then sketch an alternative account, which, while holding fast to the phenomenal compoundedness of the purple and to the impenetrability of component colours, avoids introducing inaccessible intentional objects and compromising on the continuity of the purple. According to our proposal, instead of being indistinctly perceived spatial parts of the purple, red and blue are distinctly perceived non- spatial parts of it. (shrink)

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.

Color vision provides accurate measures of the phase and intensity of daylight, and also a means of discriminating between objects. Neither property implies that objects are colored.

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.

Byrne & Hilbert's thesis, that color be associated with reflectance-type, is questioned on the grounds that it is far from clear that the human visual system is able to determine a surface's reflectance-type with sufficient accuracy. In addition, a (friendly) suggestion is made as to how to amend the definition of reflectance-type in terms of CIE (Commission Internationale de l'Eclairage) coordinates under a canonical illuminant.

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.. (shrink)

Because our only access to color qualities is through their appearance, Byrne & Hilbert's insistence on a strict distinction between apparent colors and real colors leaves them without a principled way of determining when, if ever, we see colors as they really are.

One popular materialist response to the explanatory gap identifies phenomenal concepts with type-demonstrative concepts. This kind of response, however, faces a serious challenge: that our phenomenal concepts seem to provide a richer characterization of their referents than just the demonstrative characterization of 'that quality'. In this paper, I develop a materialist account that beefs up the contents of phenomenal concepts while retaining the idea that these contents contain demonstrative elements. I illustrate this account by focusing on our phenomenal concepts of (...) phenomenal colour. The phenomenal colours stand in a similarity space relative to one another in virtue of being complex qualities—qualities that contain saturation, lightness, and various aspects of hue as component elements. Our phenomenal concepts, in turn, provide a demonstrative characterization of each of these component elements as well as a description of how much of that element is present in a given phenomenal colour. The result is an account where phenomenal concepts contain demonstrative elements and yet provide a significantly richer characterization of the intrinsic nature of their referents than just 'that quality'. (shrink)

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)

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?

The colors we perceive are the outcome of an attempt to meaningfully order the spectral information from the environment. These colors are not the result of a straightforward mapping of a physical property to a sensation, but arise from an interaction between our environment and our visual system. Thus, although one may infer from a surface’ reflectance characteristics that it will be perceived as “colored,” true colors only arise by virtue of the interaction of the reflected light with the eye (...) (and brain) of an observer. (shrink)

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.

Our reply is in three parts. The first part concerns some foundational issues in the debate about color realism. The second part addresses the many objections to the version of physicalism about color ("productance physicalism") defended in the target article. The third part discusses the leading alternative approaches and theories endorsed by the commentators.

: According to a consensus of psycho-physiological and philosophical theories, color sensations (or qualia) are generated in a cerebral "space" fed from photon-photoreceptor interaction (producing "metamers") in the retina of the eye. The resulting "space" has three dimensions: hue (or chroma), saturation (or "purity"), and brightness (lightness, value or intensity) and (in some versions) is further structured by primitive or landmark "colors"—usually four, or six (when white and black are added to red, yellow, green and blue). It has also been (...) proposed that there are eleven semantic universals—labeling the previous six plus the "intermediaries" of orange, pink, brown, purple, and gray. There are many versions of this consensus, but they all aim to provide ontological, epistemological and semantic blueprints for the brute fact of the reality of color ordained by Nature (evolution). In contrast to this consensus, we have argued that "seeing color" is not a matter of light waves impacting on our eyes, producing sensations to be categorized and labeled in the "color space" in the brain. While electrochemical events may unproblematically be regarded as the causal precondition for seeing color, the reception of sensations in "the color space" as semantically labeled natural categories, kinds, or information, is a "just so" story: it is Wittgenstein's beetle in a box. In contrast we consider that the authority of this consensus might better be regarded not as the result of the truth-tracking of nature, but as the sociohistorical outcome of philosophical presuppositions, scientific theories, experimental practices, technological apparatus, and their feed forward into the lifeworld. The question we shall therefore explore is whether, or to what extent, we ourselves are changed, as the conditions of production of color science change. Thus we are doing a kind of anthropology at two levels: of color science itself (and its effect on our own lifeworld), and of those studied by the "anthropology of color". As befits this stance we are agnostic about the theoretical entities of color science (cf. van Fraassen 2001), and within this new context, we propose to cross-cut object-and-subject, organism-and-environment (the bedrock of color science) in socio-historical ways. Our approach is in part inspired by, but not the same as, that of Gibson, in that we wish to pursue the notion of "social affordances" (Burmudez 1995). We suggest that color has become a naturalization through science-based technologies, which, through praxes and materializations, have become the perceptual and cultural entities that structure experience and understanding in the lifeworld. It is this naturalization that we shall refer to and characterize as "the historically inflected exosomatic organ". Consequently we shall explore the historical ontology of "color" without assuming an underlying biological constant (Dupré 2001). In part 1 we show the flimsiness of the evidence for the three dimensions of color, borrowed from physics, and fine-tuned to a "standard observer" (a "spectral creature" with a phenomenal "color space"). In part 2 we address the structuring of hue through the development of color circles and color spaces. This is followed by a review of the evidence for unique hues. Again the evidence is shown to be flimsy. We then show that an isolated domain of color is a particular kind of model, not a "natural given". In part 3, after reviewing what is referred to as "the isomorphy thesis," we discuss the exemplary case study of Berlin and Kay (1969). This illustrates the pull of stadial models presupposed by their evolutionary theory of color language. The Berlin and Kay paradigm proposes that American English color terms are incorrigible and can provide the universal metalanguage. We conclude by presenting an alternative account, namely that we ourselves are changed as the conditions of production of color science change. We argue that it is better to regard "seeing-color" as a historically inflected exosomatic organ that provides social affordances for those trained to grasp them. (shrink)

In visual science, color is usually regarded as a subjective phenomenon. The relationship between the specific color experiences that are evoked by a visual scene and the physical properties of the surfaces viewed in that scene are complex and highly dependent on spatial context. There is no simple correspondence between experienced color and a stable class of physical reflectances.

Those who identify colours with physical properties need to say how the content of colour experiences relate to their favoured identifications. This is because it is not plausible to hold that colour experiences represent things as having the physical properties in question. I sketch how physical realists about colour might tackle this item of unfinished business.

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.

Our understanding of the sense of taste is largely based on research designed and interpreted in terms of the traditional four tastes: sweet, sour, salty, and bitter, and now a few more. This concept of basic tastes has no rational definition to test, and thus it has not been tested. As a demonstration, a preliminary attempt to test one common but arbitrary psychophysical definition of basic tastes is included in this article; that the basic tastes are unique in being able (...) to account for other tastes. This definition was falsified in that other stimuli do about as well as the basic words and stimuli. To the extent that this finding might show analogies with other studies of receptor, neural, and psychophysical phenomena, the validity of the century-long literature of the science of taste based on a few is called into question. The possible origins, meaning, and influence of this concept are discussed. Tests of the model with control studies are suggested in all areas of taste related to basic tastes. As a stronger alternative to the basic tradition, the advantages of the across-fiber pattern model are discussed; it is based on a rational data-based hypothesis, and has survived attempts at falsification. Such has found broad acceptance in many neural systems. (shrink)

I argue that Byrne & Hilbert (B&H) have not answered Hardin's objection to physicalism about color concerning the unitary-binary structure of the colors for two reasons. First, their account of unitary-binary structure seems unsatisfactory. Second, pace B&H, there are no physicalistically acceptable candidates to be the hue-magnitudes. I conclude with a question about the justification of physicalism about color.

It is standard to suppose that, whether or not they are actually instantiated in our environment, colors are properties. Presumably those who are convinced of this thesis are convinced because they think that’s how we see colors--how visual experience represents them. I argue, in contrast, that there are cases of illusory color perception in which it is more plausible to suppose colors are represented as kinds of stuff or substance rather than as properties. I then show how to extend this (...) result to support the conclusion that colors are always represented in vision as kinds of stuff rather than as properties. In a concluding section, I consider further ways to explore and test the “stuff theory” of visual color representation. I also extract a moral from this investigation about our ability to draw accurate conclusions about our conscious visual experience. (shrink)

B&H understate the difficulties facing their version of color realism. We doubt that they can fix reflectance types and magnitudes in a way that does not invoke relations to perceivers. B&HÂ’s account therefore resembles the dispositional or ecological accounts that they dismiss. This is a good thing, for a dispositional account is promising if understood in an ecological framework.

In many cases of variation in color vision, there is no non-arbitrary way of choosing between variants. Byrne and Hilbert insist that there is an unknown standard for choosing, while eliminativists claim that all the variants are erroneous. A better response relativizes colors to perceivers, thereby providing a color realism that avoids the need to choose between variants.

“The problem of color realism” as defined in the first section of the target article, is crucial to the argument laid out by Byrne & Hilbert. They claim that the problem of color realism “does not concern, at least in the first instance, color language or color concepts” (sect. 1.1). I argue that this claim is misconceived and that a different characterisation of the problem, and some of their preliminary assumptions makes their positive proposal less appealing.

Revelation, the thesis that the full intrinsic nature of colors is revealed to us by color experiences, is false in Byrne & Hilbert's (B&H's) view, but in an interesting and nonobvious way. I show what would make Revelation true, given B&H's account of colors, and then show why that situation fails to obtain, and why that is interesting.

Our perceptual systems make information about the world available to our cognitive faculties. We come to think about the colors and shapes of objects because we are built somehow to register the instantiation of these properties around us. Just how we register the presence of properties and come to think about them is one of the central problems with understanding perceptual cognition. Another problem in the philosophy of perception concerns the nature of the properties whose presence we register. Among the (...) perceptible properties are colors and shapes, for example, and there is a long philosophical tradition of drawing and refusing to draw metaphysical distinctions between them. This paper makes a claim about the information-theoretic approach to perceptual cognition in order to argue for a fundamentally epistemological distinction between colors and shapes. What makes shapes and colors seem so different to us is how we carry information about their presence around us. In particular, we can come to know more about the shapes on the basis of perceiving them than we can come to know about the colors. One interesting feature of how this distinction is drawn is that it partially vindicates Locke’s claim that our ideas of primary qualities like shapes resemble them in ways our ideas of colors do not. (shrink)

Contemporary behavioral and brain scientists consider the existence of so-called basic emotions in a similar way to the one described by Erickson for so-called basic tastes. Commenting on this analogy, I argue that similar basic problems are encountered in both perspectives, and I suggest a potential nonbasic solution that is tested in emotion research (i.e., the appraisal model of emotion).

Byrne & Hilbert conceive of color perception as the representation of a physical property “out there.” In our view, their approach does not only have various internal problems, but is also apt to becloud both the intricate and still poorly understood role that “ color ” plays within perceptual architecture, and the complex coupling to the “external world” of the perceptual system as an entirety. We propose an alternative perspective, which avoids B&H's misleading dichotomy between a purely subjective and a (...) realist conception of “ color.”. (shrink)

The logic of the basic taste concept is discussed in relation to the physiology and psychophysics of color vision. An alternative version of the basic taste model, analogous to opponent-process theory is introduced. The logic of quality naming experiments is clarified.

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.

We discuss two modal claims about the phenomenal structure of color experiences: (i) violet experiences are necessarily experiences of a color that is for the subject on that occasion phenomenally composed of red and blue (the modal claim about violet) and (ii) no subject can possibly have an experience of a color that is for it then phenomenally composed of red and green (the modal claim about reddish green). The modal claim about reddish green is undermined by empirical results. We (...) discuss whether these empirical results cast doubt on the other modal claims as well. We argue that this not the case. Our argument is based on the thesis that the best argument for the modal claim about violet is quite different from the best argument for the modal claim about reddish green. To argue for this disanalogy we propose a reconstruction of the best available justification for both claims. (shrink)

The paper presents color as a case study for the analysis of phenomena that pertain to several levels of reality and are typically framed by different sciences and disciplines. Color, in fact, is studied by physics, biology, phenomenology, and esthetics, among others. Our thesis is that color is a different entity for each level of reality, and that for this reason color generates different observables in the epistemologies of the different sciences. By analyzing color as a paradigmatic case of an (...) entity naturally spreading over different levels of reality, the paper raises the question as to whether making explicit the usually implicit ontological assumptions embedded within the different observables exploited by the different sciences may eventually clarify some of the difficulties of developing a comprehensive theory of color. (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 study examines the cross‐cultural generality of Hering's (1878/1964) color‐opponent theory of color appearance. English‐speaking and Somali‐speaking observers performed variants of two paradigms classically used to study color‐opponency. First, both groups identified similar red, green, blue, and yellow unique hues. Second, 25 English‐speaking and 34 Somali‐speaking observers decomposed the colors present in 135 Munsell color samples into their component Hering elemental sensations—red,green,blue, yellow, white, and black—or else responded “no term.” Both groups responded no term for many samples, notably purples. Somali (...) terms for yellow were often used to name colors all around the color circle, including colors that are bluish according to Hering's theory. Four Somali Grue speakers named both green and blue elicitation samples by their term for green. However, that term did not name the union of all samples called blue or green by English speakers. A similar pattern was found among three Somali Achromatic speakers, who called the blue elicitation sample black or white. Thus, color decomposition by these Somali‐speaking observers suggests a lexically influenced re‐dimensionalization of color appearance space, rather than a simple reduction of the one proposed by Hering. Even some Somali Green‐Blue speakers, whose data were otherwise similar to English, showed similar trends in yellow and blue usage. World Color Survey data mirror these results. These within‐ and cross‐cultural violations of Hering's theory do not challenge the long‐standing view that universal sensory processes mediate color appearance. However, they do demonstrate an important contribution of language in the human understanding of color. (shrink)

In this paper I offer an explanation of the ineffability (linguistic inexpressibility) of sensory experiences. My explanation is put in terms of computational functionalism and standard externalist theories of representational content. As I will argue, many or most sensory experiences are representational states without constituent structure. This property determines both the representational function these states can serve and the information that can be extracted from them when they are processed. Sensory experiences can indicate the presence of certain external states of (...) affairs but they cannot convey any more information about them than that. So, format- or code-conversion mechanisms that link different systems of representation (linguistic and perceptual) to each other will fail to extract any relevant information from sensory experiences that could be coded in language. They only way to establish specific roles for sensory experiences in communication and the organization of behavior is to attach to them, by associative links, words, or other behavioral responses. If a sensory experience has no linguistic label associated to it in a particular subject, then no linguistic description can token, or activate, that state in the subject. In other words, no linguistic description can cause a subject to undergo an unlabeled perceptual state. On the contrary, complex, or syntactically structured perceptual states can be built up, on the basis of descriptions, by mechanisms of constructive imagination (conceived here as one sort of format conversion). It is this difference between complex and unstructured representational states that gives us an understanding of the phenomenon we call the ineffability of qualia. (shrink)

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.

We make three points. First, the concept of productance value that the authors propose in their defense of color physicalism fails to do the work for which it is intended. Second, the authors fail to offer an adequate physicalist account of what they call the hue-magnitudes. Third, their answer to the problem of individual differences faces serious difficulties.

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.

Vision scientists are interested in three diverse entities: physical stimuli, neural states, and consciously perceived colors, and in the mapping rules among the three. In this worldview, the three kinds of entities have coequal status, and views that attribute color exclusively to one or another of them, such as color realism, have no appeal.

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.

The paper examines the notion, widespread in the contemporary color science, that there are certain hues, specifically focal red, yellow, green and blue, that are unique or privileged in human prelinguistic color perception, all other chromatic hues being perceptually composed of these. I successively consider and reject all motivations that have been provided for this opinion; namely the linguistic, “phenomenological”, and some minor or historical motivations. I conclude that, contrary to the standard opinion, there is no solid reason to claim (...) that the RYGB hues are unique among colors in a sense that would allow for direct neurophysiological explanation. The notion also has no relevance for the construction of perceptual color spaces and is not defensible as an explanatory principle with respect to the existing crosslinguistic patterns of color categorization. (shrink)

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.