Cohen begins by defining ‘Color Physicalism’ so that the position is incompatible with Color Relationalism (unlike Byrne and Hilbert 2003, 7, and note 18). Physicalism, in any event, is something of a distraction, since Cohen’s argument from perceptual variation is directed against any view on which minor color misperception is common (Byrne and Hilbert 2004). A typical color primitivist, for example, is equally vulnerable to the argument. Suppose that normal human observers S1 and S2 are viewing a chip C, as (...) in Cohen’s example. C looks unique green to S1, and bluish green to S2. The problem, as Cohen has it, is to explain “what could (metaphysically) make it the case” that S1, say, and not S2, is perceiving C correctly. He purports to find the explanation “extremely hard to imagine”, and so concludes that both S1 and S2 are perceiving C correctly. (That is not the only option, of course: Hardin concludes that neither is perceiving the chip correctly.). (shrink)