According to David Armstrong (1997, 67–8) “The kinds mark true joints in nature. But it is not clear that we require an independent and irreducible category of universal to accommodate the kinds”. Armstrong’s view is naturalistic, since there are genuine natural divisions; but he is also resistant to realism. If there were natural kinds they would be universals. But the properties shared by all and only the members of a kind will typically be very complex. For example, he considers whether there