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?

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.

Do the physical facts of the viewed environment account for the ordinary experiences we have of that environment? According to standard philosophical views, distal facts do account for our experiences, a phenomenon explained by appeal to perceptual constancy, the phenomenal stability of objects and environmental properties notwithstanding physical changes in proximal stimulation. This essay reviews a significant but neglected research tradition in experimental psychology according to which percepts systematically do not correspond to mind-independent distal facts. Instead, stability of percept values (...) comes in degrees, and physical facts about the viewed environment alone do not account for our ordinary experiences of the world. I conclude that more attention to descriptive research in psychophysics is warranted if what is sought is a philosophical theory of the nature of our perceptual relation with the world. (shrink)

I argue that when empty space is seen in mirrors—that is, when perceptual specular experience is veridical—specular empty space is, like pictorial empty space, seen-in. I explain how the phenomenal expansiveness of specular reflections can nonetheless be reconciled with the see-through look of specular space.

I draw on Carl Stumpf’s essay “Psychologie und Erkenntnistheorie”, and his precocious On the Psychological Origin of the Idea of Space, to set out a charge he raises against Kant’s fo...

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)

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.

Students of perception have long puzzled over a range of cases in which perception seems to tell us distinct, and in some sense conflicting, things about the world. In the cases at issue, the perceptual system is capable of responding to a single stimulus — say, as manifested in the ways in which subjects sort that stimulus — in different ways. This paper is about these puzzling cases, and about how they should be characterized and accounted for within a general (...) theory of perception. After rehearsing the sort of case at issue (§1), I’ll examine critically some of the strategies by which philosophers and perceptual psychologists have attempted to account for them (§2). Finally, I’ll present an alternative computational account of the puzzle cases, argue that this view is superior to its competitors, and examine some of its implications (§3). (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.

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)

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.

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.

A coin rotating back in depth in some sense presents a changing, elliptical shape. How are we to understand such (in this case) ‘appearances of ellipticality’? How is the experiential sense of such shifting shape appearances related to the experiential sense of enduring shape definitive of perceived shape constancy? Is the experiential recovery of surface shape based on the prior (perhaps more fundamental) recovery of point or element 3D spatial locations?—or is the perception of shape a largely independent perceptual achievement? (...) Do we gain access to enduring shape properties by first detecting and working from ‘shape appearances’? These are some of the topics taken up in this paper. (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.

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 paper presents analysis of form in different domains. It draws on the commonalities and their potential unified classifications based on how forms subjectively appear in perception—as opposed to their standard specification in Euclidean geometry or other objective quantitative methods. The paper provides an overview aiming to offer elements for thought for researchers in various fields.

Nowadays cognitive science often views sensorial presentations and mental presentations as mutually exclusive, and they are also given separate treatment by neurophysiologists and by cognitive scientists, and some phenomena (like anomalous surfaces or various types of imagery) are reduced to either the former or the latter. Since no adequate methods for its investigation have been developed, the level of perceptual experiences analysed by Gestaltists and magnificently illustrated by Metzger in his Laws of Seeing remains unexplored. Starting from Metzger’s analyses the (...) paper deals with the question of the theoretical value of experimental phenomenology to the theory of knowledge and ontology. (shrink)

Space—an essential dimension of our life—is analyzable from different viewpoints, which often gives rise to contrasting conceptualizations. Perceptual analyses shed light on the intrinsic anisotropy and deformations of perceived space, raising the issue of which geometry may be able to represent perceptual space. Pictorial drawings and painting have been relevant sources of information about the nature of living and perceived space. Although the geometry of perceptual space is still in its infancy, contributions are beginning to appear. This special issue contributes (...) to the development of the geometry of perceptual space. (shrink)

The apparent dichotomy between qualitative versus quantitative dimensions in science intersects with the domain of several disciplines, as well as different research fields within one and the same discipline. The perception of qualitative as “poor quantitative,” however, is methodologically unsustainable, because there are perfectly rigorous ways to conduct qualitative research. A somehow different question is whether a science of qualities per se is possible: that is, whether a science of appearances can be devised, what its observables are, and its methodological (...) implications. The article deals with this last issue, and especially from the point of view of experimental phenomenology. The weakness of the current approach to perception is discussed, and an alternative view that goes beyond veridicalism is presented. The analysis tackles crucial issues such as color and spatial appearances, the qualitative dimension of perceived depth, and the role of visual meaningful gestalten as information tools for the survival of living beings in the environment. If developed, a science of the qualitative dimensions of appearances may contribute to revising the ecological theory of perception by making its natural semantics more explicit. (shrink)

Along with hallucinations and illusions, afterimages have shaped the philosophical debate about the nature of perception. Often referred to as optical or visual illusions, experiences of afterimages have been abundantly exploited by philosophers to argue against naïve realism. This paper offers an alternative account to this traditional view by providing a tentative account of the colors of the afterimages from an objectivist perspective. Contrary to the widespread approach to afterimages, this paper explores the possibility that the colors of afterimages are (...) not ontologically different from “ordinary” colors and that experiences of afterimages fail to provide a motivation for rejecting naïve realism. (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.

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.

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.

Tertiary qualities have been studied primarily by Gestalt psychologists. My aim in this article is to revisit the theoretical assumptions regarding tertiary qualities. I start from the Galilean distinction of the qualities of experience, the Lockean subdivision of qualities, the subjectivist definition in aesthetics and the theoretical contribution of Gestalt theory, to show the theoretical value of ‘tertiary qualities’ in the current context of experimental psychological research. I conclude that tertiary qualities are a crucial keyword for an experimental psychology based (...) on the primacy of perception. Such a perspective is in favour of a neo-Gestalt Experimental Phenomenology. (shrink)

Summary The present paper introduces the theoretical conceptualization of perceptual communication through expressive qualities. Initially, the difference with respect to the modality of perceptual communication mediated by signs is analyzed. Conversely, the theory of expressive qualities reflects the psychological conception of direct perception: any assumption of a cognitive stage of representation is excluded. Perceptual communication immediately expresses the specific character of the structural essence of the object. The structural essence is well studied by the perceptual paradigms of Experimental Phenomenology. Plurivocity, (...) the case in which the same objects can share many expressive characters, is also considered. (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.

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.

The empirical study of visual space has centered on determining its geometry, whether it is a perspective projection, flat or curved, Euclidean or non-Euclidean, whereas the topology of space consists of those properties that remain invariant under stretching but not tearing. For that reason distance is a property not preserved in topological space whereas the property of spatial order is preserved. Specifically the topological properties of dimensionality, orientability, continuity, and connectivity define “real” space as studied by physics and are the (...) spatial properties that characterize the physical universe as being an integral whole. By contrast the geometrical analysis of VS has taken little cognizance of its topology. Instead such properties have been presupposed a priori rather than being established a posteriori by empirical means, perhaps because these properties are self-evident. Applying the method of coordinative definition expounded by Hans Reichenbach for determining geometrical and topological properties of physical space, it can be shown that VS fulfills the topological criteria of being a “real” space sui generis. Though theorized to be produced by the brain, the topology of VS is not topologically equivalent with the structure and activity of the brain because, as will be shown, the topology of VS cannot be formed from the topology of the brain without tearing and/or cutting and pasting. (shrink)

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.

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.

Perceptual constancy, often defined as the perception of stable features under changing conditions, goes hand in hand with variation in how things look. A white wall in the orange afternoon sun still looks white, though its whiteness looks different compared with the same wall in the noon sun. Historically, this variation has often been explained in terms of our experience of “merely sensory” or subjective properties – an approach at odds with the fact that the variation does track objective features (...) of the perceptual situation, such as illumination. One approach, becoming more common, is to account for the variation in terms of further “dimensions” to perceptual experience. Especially in colour perception, this is a natural thought to have but the idea is often left vague. In this paper I argue that the “dimensional” strategy has problems of its own, but is useful in drawing out some interesting complications in the way perceptual experience is structured. Specifically, the structure of “constancy spaces” brings out the different ways in which there is stability and instability in the experience of constancy, without the need for novel or merely subjective features. Instability arises in a contingent structural feature of perceptual experience. (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.

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.

Loneliness is more complex and multi-faceted than it may appear at first glance. Most of the characterizations that we have of loneliness in the extant literature tend to focus on the absence of other people and on the social, mental, and physical distress that can be caused by this type of absence. Although the experience of absence may be a fundamental and encompassing aspect of loneliness, loneliness may also reflect a deeper, more complex experience. This paper integrates data from a (...) qualitative study on the phenomenology of loneliness with philosophical theories on the self. It argues that there is a connection between the experience of absence and the impossibility to appear in the world and that this may consequentially lead to the disruption of self-experience. (shrink)

Along with hallucinations and illusions, afterimages have shaped the philosophical debate about the nature of perception. Often referred to as optical or visual illusions, experiences of afterimages have been abundantly exploited by philosophers to argue against naïve realism. This paper offers an alternative account to this traditional view by providing a tentative account of the colors of the afterimages from an objectivist perspective. Contrary to the widespread approach to afterimages, this paper explores the possibility that the colors of afterimages are (...) not ontologically different from “ordinary” colors and that experiences of afterimages fail to provide a motivation for rejecting naïve realism. (shrink)

Most objectivist and dispositionalist theories of color have tried to resolve the challenge raised by color variations by drawing a distinction between real and apparent colors. This paper considers such a strategy to be fundamentally erroneous. The high degree of variability of colors constitutes a crucial feature of colors and color perception; it cannot be avoided without leaving aside the real nature of color. The objectivist theory of color defended in this paper holds that objects have locally many different objective (...) colors. Most color variations are then real and result from the extreme richness of color properties. (shrink)

“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.

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)

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.

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.

I ask whether figure-ground structure can be realized in touch, and, if so, how. Drawing on the taxonomy of touch sketched in Katz's 1925 The World of Touch, I argue that the form of touch that is relevant to such consideration is a species of immersed touch. I consider whether we can feel the space we are immersed in and, more specifically, the empty space against which the surfaces of objects, as I shall urge, “stand out.” Harnessing M. G. F. (...) Martin's account of bodily awareness and touch, I defend a positive thesis, pace Graham Nerlich on whose The Shape of Space I otherwise rely, both to defend the supposition that empty space can in principle be felt and to argue that touching empty space is not a mere species of absence perception. Along the way, I defuse a causal worry that might be thought to arise in the case of touching empty space. (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.

Rationalizing the perceptual effects of spectral stimuli has been a major challenge in vision science for at least the last 200 years. Here we review evidence that this otherwise puzzling body of phenomenology is generated by an empirical strategy of perception in which the color an observer sees is entirely determined by the probability distribution of the possible sources of the stimulus. The rationale for this strategy in color vision, as in other visual perceptual domains, is the inherent ambiguity of (...) the real-world origins of any spectral stimulus. (shrink)

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.

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)

This paper explores the confrontation of physical and contextual factors involved in the emergence of the subject of color measurement, which stabilized in essentially its present form during the interwar period. The contentions surrounding the specialty had both a national and a disciplinary dimension. German dominance was curtailed by American and British contributions after World War I. Particularly in America, communities of physicists and psychologists had different commitments to divergent views of nature and human perception. They therefore had to negotiate (...) a compromise between their desire for a quantitative system of description and the perceived complexity and human-centeredness of color judgement. These debates were played out not in the laboratory but rather in institutionalized encounters on standards committees. Groups such as this constitute a relatively unexplored historiographic and social site of investigation. The heterogeneity of such committees, and their products, highlight the problems of identifying and following such ephemeral historical 'actors'. (shrink)

The ArgumentThis paper explores the confrontation of physical and contextual factors involved in the emergence of the subject of color measurement, which stabilized in essentially its present form during the interwar period. The contentions surrounding the specialty had both a national and a disciplinary dimension. German dominance was curtailed by American and British contributions after World War I. Particularly in America, communities of physicists and psychologists had different commitments to divergent views of nature and human perception. They therefore had to (...) negotiate a compromise between their desire for a quantitative system of description and the perceived complexity and human-centeredness of color judgment. These debates were played out not in the laboratory but rather in institutionalized encounters on standards committees. Such groups constitute a relatively unexplored historiographic and social site of investigation. The heterogeneity of such committees, and their products, highlight the problems of identifying and following such ephemeral historical “actors”. (shrink)

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.