What Is Color and How Did We Come to Experience It?
The short answer to the first part of the chapter title question is: we do not know. Many readers may be surprised to learn that as yet there is no detailed scientific explanation of the color vision process or the vision process in general. Light passing through the lenses of our eyes is absorbed by the two-dimensional, curved layer of four kinds of light-sensitive cells of the retina, where its absorption produces electrochemical signals (see Chapter 3). They pass through various stages into the brain, somehow creating the visual world in front of us that normally sighted people experience. There are various ideas of how this might work, but none that is all encompassing and generally found to be valid. A considerable amount has been learned in the last several decades about neurophysiological processes involved in color vision. But there continues to be a black box in our brain into which biologically produced signals disappear and out of which general vision and color experiences appear.
Like all other senses and functions of the body, the visual sense has many aspects. There is the comparatively well-known anatomical aspect: the eye with its parts and the strands of nerve fibers from the eyes to the different regions of the brain. There is the physical/optical aspect: the description of light, its interaction with objects, ...