It is often claimed, following Joseph Levine, that there is an ‘explanatory gap’ between ordinary physical facts and the way we perceive things, so that it is impossible to explain, among other things, why colours actually look the way they do. C.L. Hardin, by contrast, argues that there are sufficient asymmetries between colours to traverse this gap. This paper argues that the terms we use to characterize colours, such as ‘warm’ and ‘cool’, are not well understood, and that we need to understand the neurological basis for such associations if we are even to understand what is fully meant by saying, for example, that red is a warm colour. This paper also speculates on how Hardin’s strategy can be generalized.