Color seems so obscure right now. We see it all of the time, yet there is so much processing that goes on nearly instantaneously. It is surprising that most people have the same ideas of colors in their brain. There is so much talk about how people are different and how raising a child in a particular way can affect how that child behaves later in life. Knowing that color is (or may be) phony, i question how it is relatively constant. Like every other output we have studied, our interpretation of color is a pattern of activity across neurons in the brain. The input we are working with here is also a pattern like with output.

Behavior is too complex. We pick at little parts and see how much goes into just a little bit of output. I like learning about color vision and I understand how it works. I do not quite see your justification for why it is phony though. Depending on whether photons hit rods or cones determines color or not. What is wrong with that? It just means that we need a more intense light to be able to see color. And there also seems to be little problem with the idea that three separate wavelengths can produce the same color in the brain as one monochromatic light. We know that from playing with art when we were younger - how colors could mix and create other colors. Although light follows slightly different rules, it does not surprise me of the results or lead me to think that color is not for real. Am I questioning?

Yep. Are skeptical. Which is fine. Hope, by the end of the course (maybe that's too soon? we can keep working on it after), the deeper issues making you skeptical will become clear. Regardless, I agree that what we know raises interesting questions about how come different brains exhibit such agreement (presumably because, despite their differences there are also substantial similarities, AND because, despite the inability to KNOW there is a real world out there, our collective experiences strongly suggest there is something stable influencing all our experiences). All of which bears on the "phoniness of color". No, there is nothing particularly surprising in the observations which lead to that conclusion: things don't looked colored unless they are bright enough, and colors when mixed together give other colors. What is surprising to many people, and is I think important in any case, is that "color", as we use the term in everyday discussion, is a concept and category created by the brain, one which makes sense only in those terms, rather than an attribute of the (hypothetical) external reality in which we live. What is "real" (as far as we know) in the external reality is wavelength. Photons have wavelengths; what they don't have is "color". Three lines of evidence. First, the same photons produce "color" is absorbed by cones, do not produce "color" if absorbed by rods. Second, a particular color is perceived if particular photons are absorbed by cones, but can equally well be perceived in the absence of any of those photons when appropriate mixes of other photons are absorbed by cones. Third, a particular photon, or mix of photons arising from a given point source, will give rise to different colors, depending on the photons being absorbed from other point sources in the visual scene. In short, color corresponds to a particular pattern of activity in the brain, which bears no one to one relationship to the wavelength of the photons being absorbed. Color is very "real", to US. It just doesn't happen to be, as we usually think, an attribute of external reality. That help? PG