Thursday, July 10, 2014

Colors and Looks (1)
In 1976, when I delivered the John Locke Lectures at Oxford, I often spent time with Peter Strawson, and one day at lunch he made a remark I have never been able to forget. He said, "Surely half the pleasure of life is sardonic comment on the passing show".  This blog is devoted to comments, not all of them sardonic, on the passing philosophical show.
Hilary Putnam

In a previous post (“Escher Colors”, 6/11/14), I pointed out that that colors do not look the same to all normal people, on any reasonable construal of ‘normal’.  (See also Ned Block’s “Wittgenstein and Qualia”, in Maria Baghramian (ed.), Reading Putnam.)  As I pointed out in that post, colors do not look quite the same when viewed with one eye closed and when viewed with both eyes open, or when viewed with the other eye closed, even when the illumination and the distance and the angle of vision, etc., are held constant. There is a temptation to think that the questions, “Does my right eye see such the color of such and such as it really is?” and “Does my left eye see such the color of such and such as it really is?” make sense, but on reflection one realizes that they don’t. “The color I see”, as Russell would have put it in The Problems of Philosophy, isn’t a color anything could “really be”, for if it were then “The color I see when my left eye is shut” could be the real color of the object, and “The color I see when my right eye is shut” could equally be the real color of the object, but those “colors” are not the same, and the object could not be both colors at once.  Subjective colors are what I called “Escher colors”; phenomenologically it seems as if they are “diaphanous”, as if each eye in turn is seeing the object “as it really is”, but it is impossible for any object then to be both of those ways, and, given that neither way of looking is the way the object looks to all normal people in those circumstances, neither is there any sense in saying one way of looking is “veridical” and the other “non-veridical”. So I argued in that post.
But why not conclude, a friend asks, that colors aren’t real?  The “person on the street” project colors onto the surfaces of objects,  but they aren’t really there. This was, indeed, Russell’s view, and, before him, the view of Hume as well (except that Hume thought that objects aren’t really “out there” either, but that is another story). 
This story about how the person on the street mistakes what is in her own mind for properties of “external things” has not gone unchallenged. In the 18th century, Thomas Reid, Hume’s great contemporary and rival, argued that the person on the street knows perfectly well the difference between a color and a sensation, and he was absolutely right. We do not think that objects change their color between 10AM and 7PM, although the look of any given colored object changes. We don’t think an object changes color when a cloud passes over the sun, although we are all aware that its look changes. Most people are not aware of the variability of subjective looks, for example, that objects that look bluish green to one person might look pure green to another, and the phenomenon of fine shades of difference in the apparent saturation of colors owing to differences in the pigmentation in (“normal”) macular areas that I mentioned in Escher Colors was unknown to even the optical technician I mentioned in that post, but that a color has a number of different looks depending on the conditions is not news. Reid was right, that the empiricist story makes the person on the street too na├»ve.
An old story, which is not as uncharitable to the person on the street as the claim that she projects what are really subjective looks onto the surfaces of objects goes like this:  colors are dispositions to produce certain sense data (under appropriate conditions). This story still assumes the person on the street is confused: she thinks that her sense data are looks of objects in an objective sense, the sort of looks that can be recorded with a camera. According to this story, she does not realize that what she calls “looks” are themselves sense data. But she does know that the dispositions to have those looks is a property of the objects, and she does not agree with Russell’s view that the objects themselves are never experienced, but at best “inferred”.
But this story too has problems (which I will talk about in the next post).
My interest in all this is not merely historical. The relations and distinctions between objective and subjective looks, objective colors, sense data (or to use the currently fashionable term, qualia), perception, experience, and apperception, are all topics Hilla Jacobson and I have been discussing for seven years, as we work on a planned book on apperception and consciousness,  and we have eached published things that touch on these topic  (and also have forthcoming unpublished papers on them).  In posts subsequent to this one, I plan to continue my answer to my friend’s question, why I persist in the view that colors are real. But I can  give a preliminary answer: it is nowadays a respectable (and I believe correct) view that many (though not all sorts of) dispositional properties of objects are explanatory and ontologically robust. Properties that enter into explaining the survival value of various phenotypes (and hence of the corresponding genotypes in certain environments) are explanatory and robust in this way. And colors are such properties, as evidenced by the fact that convergent evolution has led very different species (e.g., humans and at least one species of octopus) to develop eyes able to differentially respond to colors. [See Gunzo Kawamura, Kazuo Nobutoki, Kazuhiko Anraku, Yoshito Tanaka, and Masaru Okamoto, "Color Discrimination Conditioning in Two Octopus Octopus aegina and O. vulgaris", Nippon Suisan Gaikashi, vo. 67 (2001), pp. 35-39,]
I don’t believe colors are dispositions to produce particular sense data, as will be explained in subsequent posts. But it is plausible that they are dispositions to affect light reflected from the objects that have those disposition in certain ways, ways that in turn affect our eyes (and those of Octopus aegina), and thereby enable us (and O. aegina) to identify and re-identify those objects more easily.
Of course, if you think that things as intuitively different and colors and dispositions (of the kind just mentioned) just cannot be contingently identical—if you don’t think that science can and does discover non-analytic identities between properties—then you will reject this account of colors as physical dispositions out of hand. But then, I have long argued, you are making a serious mistake. [See my (1970) “On Properties”, collected in Mathematics, Matter, and Method, vol. 1 of my Philosophical Papers (1975).]