Via Tanasije I found Michael Tye’s paper The Puzzle of True Blue where he considers the problem posed by the well known fact that people’s color discriminations vary widely from person to person. So you and I could both be looking at some particular color and I might think that it is true blue, not at all greenish while you might think that it is not true blue (a little bit greeninsh). Tye considers some standard answers to the puzzle before presenting his own. I will skip the standard ones and go straight to Tye’s.

 He suggests that the visual system evolved to respond to the general color categories and that the particular shade of the general color is unimportant and so a sort of ‘”guess” on the part of the visual system. But there is yet another alternative account. It may be the case that you and I have the same first order mental states of the determinate shade and different higher-order representations of that first-order state. The same sort of story could be told…In order to determine which is right we would have to present the colors to the subjects subliminally, record the brain activity, present the colors to the subject superliminally, record the brain activity and note the differences…