It is very natural to wonder if other people see colours in the same way as we do (for example, that you see red where I see green, and vice versa), for there is no obvious way of telling one way or the other. The hypothesis of inverted qualia, in particular of inverted colour hues, goes back at least as far as the Cyrenaics, and is still a major topic of philosophical investigation. There are several reasons for this. Sometimes, the hypothesis is used to argue for a general scepticism about other minds. Sometimes, it is used to argue against functionalist analyses of mental concepts. My suggestion is that its most important philosophical purpose concerns explanation: in particular the explanation of why colours actually look the way they do. This is a scientific-cum-philosophical task of considerable importance in its own right, and it does not require us to take sceptical hypotheses unduly seriously, or to provide alternative analyses of mental concepts.