Online research in philosophy

It is argued that color constancy is only one of the benefits of color vision and probably not the most important one. Attention to a different benefit, chromatic contrast, suggests that the features of the environment that played a role in the evolution of color vision are properties of particular ecological niches rather than properties of naturally-occurring illumination. [Shepard].

This book is a major contribution to the interdisciplinary project of investigating the true nature of color vision. In recent times, research into color vision has been one of the main success stories of cognitive science. Each discipline in the field--neuroscience, psychology, linguistics, computer science and philosophy--has contributed significantly to our understanding of color. Evan Thompson provides an accessible review of current scientific and philosophical discussions of color vision. He steers a course between the subjective and objective positions on color, arguing for a relational account. Thompson develops a novel "ecological" approach to color vision in cognitive science and the philosophy of perception. The book is vital reading for all cognitive scientists and philosophers whose interests touch upon this central area.

It seems intuitively obvious that metameric matching of color samples entails a loss of information, for spectrophotometrically diverse materials appear the same. This intuition implicitly relies on a conception of the function of color vision and on a related conception of how color samples should be individuated. It assumes that the function of color vision is to distinguish among spectral energy distributions, and that color samples should be individuated by their physical properties. I challenge these assumptions by articulating a different conception of the function of color vision, according to which color vision serves to partition object surfaces into discrimination classes.

Our question is: how do things look to the color-blind? But what does that mean? Who are the “color-blind”? Approximately 7% of males and fewer than 1% of females (of European descent1) have some form of inherited defect of color vision, and as a result are unable to discriminate some colored stimuli that most of us can tell apart. (‘Color defective’ is an alternative term that is often used; we will continue to speak with the vulgar.) 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. The most common form of dichromacy (afflicting about 2% of males) is red-green color blindness, or red-green dichromacy, which itself comes in two varieties. A red-green dichromat will not be able to distinguish some pairs of stimuli that respectively appear red and green to those with normal color vision. For simplicity we will concentrate almost exclusively on red-green color blindness.2 In a philosophical context our question is liable to be taken two ways. First, it can be straightforwardly taken as a question about visible properties of external objects like..

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.

1. Introduction Our question is: how do things look to the color-blind? But what does that mean? Who are the “color-blind”? Approximately 7% of males and fewer than 1% of females (of European descent1) have some form of inherited defect of color vision, and as a result are unable to discriminate some colored stimuli that most of us can tell apart. (‘Color defective’ is an alternative term that is often used; we will continue to speak with the vulgar.) 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. The most common form of dichromacy (afflicting about 2% of males) is red-green color blindness, or red-green dichromacy, which itself comes in two varieties. A red-green dichromat will not be able to distinguish some pairs of stimuli that respectively appear red and green to those with..

This book is a major contribution to the interdisciplinary project of investigating the true nature of color vision.

What is color? What is color vision? Most philosophers answer by reference to humans: to human color qualia, or to the environmental properties or "quality spaces" perceived by humans. It is argued, with reference to empirical findings concerning comparative color vision and the evolution of color vision, that all such attempts are mistaken. An adequate definition of color vision must eschew reference to its outputs in the human cognition and refer only to inputs: color vision consists in the use of wavelength discrimination in the construction of visual representations. A color quality is one that is generated from such processing.

Al-Kindi was influenced by two Greek traditions in his attempts to explain vision, light and color. Most obviously, his works on optics are indebted to Euclid and, perhaps indirectly, to Ptolemy. But he also knew some works from the Aristotelian tradition that touch on the nature of color and vision. Al-Kindi explicitly rejects the Aristotelian account of vision in his De Aspectibus, and adopts a theory according to which we see by means of a visual ray emitted from the eye. But in the same work, al-Kindi draws on Philoponus.