Abstract

This article explores what Diderot's treatment of Molyneux's question can teach us about qualia. Is there within perception an irreducible dimension of sensory donation that grants us access to specific knowledge, which cannot be obtained otherwise? In section 1, I place the story of the child who would never have seen red in the Essay Concerning Human Understanding in relation to Jackson's example of Mary the physicist who knows the whole theory of optics without ever having seen a colour. In section 2, I reinterpret Diderot's response, which offers an alternative approach to Molyneux's question and consequently to the problem of qualia. Indeed, Diderot considered the idea that a blind mathematician, upon gaining sight, could distinguish and demonstrate the respective properties of the circle and the square.