ABSTRACT
The classical version of the well known puzzle of the inverted spectrum stems from the idea that two people could have systematically inverted colour perception with no external behavioural indication of the difference and no internal functional difference either. While the representational theory offers a nice treatment of this issue, difficulties lurk over the horizon. Dretske accepts that two people could have identical discriminatory powers but differ in the qualities of their experience (1995, p. 72). But they would nonetheless have to differ in some objective way. Speaking abstractly, there seem to be only two possible objective differences available within the confines of the bio-functional version of the representational theory. Either the two could differ in the functions of the sensory systems that ground their discriminatory abilities or the two could differ in the implementation of systems with the same sensory functions.
