9.01.2002

I have been wandering through a number of works by cognitive psychologists on perception and color perception. Their vocabulary is derived uniformly from what we can call the neurophysiology of binocular vision. What is remarkable is how far our understanding of perception has moved from the idea that the visual cortex serves as a passive receiver of information and toward a more dynamic conception to the effect that we create what we see according to neurologically wired rules. Let me cite Donald Hoffman on this point and then move on to an anti-philosophical conclusion. "When you construct color," writes Hoffman, "you do not construct just color. Instead you construct several visual properties at once, and try to make them all mutually consistent: you organize your visual world into objects, you endow those objects with three-dimensional shapes, place light sources that illuminate those objects, and assign color to both the light sources and the objects. As always, images are infinitely ambiguous. There are countless ways that you could interpret an image in terms of objects, their shapes, their colors, and their illuminants. You could trade off surface color for illuminant color, or surface shape for surface color. The possibilities are endless. But, again, you have rules, quite sophisticated rules that researchers are just beginning to uncover, by which you select one interpretation from the countless possibilities." [Donald Hoffman, Visual Intelligence: How We Create What We See N.Y.: Norton, 1998, pp. 113-14]

As I read Hoffman, I had an odd feeling that I had seen another, remarkably similar, description of seeing color. Maurice Merleau-Ponty wrote an essay on Cezanne's technique that focuses on how the artist achieved the effect of illumination from within the still life on canvas. "The use of warm colors and black shows that Cezanne wants to represent the object, to find it again behind the atmosphere. Likewise he does not break up the tone; rather, he replaces this technique with graduated colors, a progression of chromatic nuances across the object, a modulation of colors which stays close to the object's form and to the light it receives...The object is no longer covered by reflections and lost in its relationships to the atmosphere and other objects; it seems subtly illuminated from within, light emanates from it, and the result is an impression of solidity and material substance." (Merleau-Ponty, "Cezanne's Doubt," in Sense and Non-Sense Northwestern U. Press, 1964, p. 12)

What Hoffman argues is that we are all Cezanne's. Ordinary seeing is actually an act of artistic creation. The idea of seeing as representational simply goes out the window. And, yet, philosophers remain enamored with the idea of truth as the accurate representation of reality. They remain so despite devastating critiques from fellow philosophers. If anything, although Hoffman is not nearly the writer Wittgenstein was, his argument is more persuasive because it is backed by evidence advanced in the vocabulary of science. In the boundary dispute between philosophy and neuroscience, the latter eliminates the former. Or it forces an opening of philosophy to what is going on outside its disciplinary boundaries. We can make the opposite point as well -- that scientists would do well to keep up with what philosophers are saying about our relation to reality -- but it is philosophy that is facing the fate of phrenology.

On your point regarding non-human species, we can extend Hoffman to say that because there are neurological similarities in the visual cortexes of humans and dogs, both engage in creative perception. We can make the same case for extending rules against torture of humans to non-human species. Indeed, we could go so far as to extend rights to any species with a central nervous system. Pace Thomas Nagel, we can indeed know something about what it is like to be a bat.

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