Abstract

Recent scientific findings have addressed matters of concern to philosophers interested in color perception and the place of color in the physical world. There has been some progress in understanding the neural basis of the unique hues, but it has been slower than one might have hoped. Opponency can indeed break down; the perception of red-green binaries has been confirmed using improved methodology. Variation of color perception among normal observers is manifested in substantial differences in the loci of unique hues as well as in variations in metameric matching. The sources of the former variation are not well understood, but the latter have been shown to depend in part on polymorphisms of visual photopigments that have only been discovered in the last few years. These are genetically sex-linked and raise the possibility of female tetrachromats. Indeed, the existence of at least one female (retinal) tetrachromat has now been confirmed. All of these variations pose the question of which, if any, normal observers perceives colors veridically.