The concentration camp at Auschwitz kept stunningly and chillingly meticulous records on its inmates. One particularly striking aspect of this was the wide range of badges which had to be worn to indicate one’s categorization: Jew, gypsy, homosexual, political offender and so on, and all the cross-categorizations they gave rise to. This paper is about badges of identity and the conditions which give rise to them. No one can say in advance what features of your identity will assume greatest salience in particular historical circumstances. For millions of people it has been their race or their nationality, with tragic results. For some individuals, in some situations, it has been something as contingent and fortuitous as the football scarf they happened to be wearing, with similarly tragic results for them. In this discussion I try to make sense of the interplay between contingent and necessary features of human beings in the formation of social identity. Any such discussion is bound to be coloured by recent debates between liberals and communitarians, but my paper is not strictly about that debate. Rather, it attempts to dig down to deeper presuppositions about what human beings are like and to subject them to greater scrutiny than they are able to receive within the terms of that debate.