One of the reasons colours, or better the conceptual organisation of the colour system, could be relevant to the philosophy of logic is that they necessitate some mutilation of truth tables by restricting truth functionality. This paper argues that the so-called ‘Colour Exclusion Problem’, the first great challenge for Wittgenstein’s Tractatus, is a legitimate philosophical motivation for a systematic mutilation of truth tables. It shows how one can express, through these mutilations, some intensional logical relations usually expressed by the Aristotelian (...) Square of Oppositions, as contrariety and subcontrariety. (shrink)