Online research in philosophy

From now on I will assume that it is possible in principle for there to be cases of spectrum inversion in which the invertees are equally good perceivers of the colors. What I want to show next is that while allowing this possibility is incompatible with standard representationalism, it requires acceptance of a different version of representationalism. Consider the standard way of describing a case of spectrum inversion. Returning to Jack and Jill, we say that red things look to Jack the way green things look to Jill, blue things look to Jack the way yellow things look to Jill, and so on. Of course, we might also express this by saying that the phenomenal character of Jack’s experience of red things is like the phenomenal character of Jill’s experience of green things, and so on. Or by saying that “what it is like” for Jack to see red things is “what it is like” for Jill to see green things, and so on. But “phenomenal character” is philosophical jargon, and “what it is like” is on its way to being that. We need to be able cash these locutions in terms that we are sure we understand. And I think that the best way of doing that is in terms of how things look. Now the sense in which red things look different to Jack and Jill cannot be that they look to have different colors in the epistemic sense. We can suppose that both perceive red things as being red, and therefore that to both red things look red in the epistemic sense. Nor can it be the comparative sense – to each, we can suppose, red things look like standard red things under standard conditions. The remaining sense of “looks” is supposed to be the phenomenal sense. Now those who employ this notion typically speak of things as looking red, blue, yellow, etc., in the phenomenal sense. But if Jack and Jill are both accurate perceivers of the colors of things, it can’t be that the difference in how things look to them is a difference in what colors things look to them, even if “looks” is used in the phenomenal sense..

PURPLE (RED-and-BLUE) is the most frequently occurring derived (binary) basic color term (BCT), but there is never a named composite BCT meaning RED-or-BLUE. GREEN-or-BLUE is the most frequently named composite color category, but there is never a BCT for the corresponding derived (binary) category CYAN (BLUE-and-GREEN). Why?

Ewald Hering's color-opponent-theory is still considered one of the foundations of the visual sciences. Prior to Hering, Hermann v. Helmholtz introduced a theory of color appearance, which was based primarily on the physical aspects of the stimulus. In contrast to Helmholtz, Hering's theory strongly emphasized the subject's perception of color. As a consequence, Hering considered Helmholtz' theory inadequate. Contrary to some historical accounts, he did not object to Helmholtz's three-receptor explanation for color-mixture. Instead of Helmholtz' fundamental colors red, green, and blue, Hering suggested that the colors possess opponent character: blue-yellow; red-green; and, black-white. Helmholtz, on the other hand, refused to accept Hering's theory. Finally, a student with Helmholtz, Johannes v. Kries, developed the so-called zone-theory , which combines both, Young-Helmholtz's and Hering's theory at different stages of the visual information processing system.

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.

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.

Traditional theories locate color in primary qualities of objects, in dispositional properties of objects, in visual fields, or nowhere. In contrast, we argue that color is located in properties of light. More specifically, light is red iff there is a property P of the light that typically interacts with normal human perceivers to give the sensation of red. This is an error theory, because objects and visual fields that appear red are not really red, since they lack the properties that make light red. We show how this light theory solves or avoids problems that afflict its competitors.

Most men and nearly all women have non-defective colour vision, as measured by standard colour tests such as those of Ishihara and Farns- worth. But people vary, according to gender, race and age in their per- formance in matching experiments. For example, when subjects are shown a screen, one half of which is lit by a mixture of red and green lights and the other by yellow or orange light, and they are asked to ad- just the mixture of lights so as to make the two halves of the screen match in colour, they disagree about the location of the match. Where one male subject sees the two sides of the screen as being the same in colour, an- other female subject may see one side as a little redder or greener. And there are corresponding differences with age and race.

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..

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..