Full Idea
A problem for resemblance nominalism is that in saying that two particulars 'resemble' one another, it is necessary to specify in what respect they do so (e.g. colour, shape, size), and this threatens to reintroduce what appears to be talk of universals.
Gist of Idea
Two things can only resemble one another in some respect, and that may reintroduce a universal
Source
E.J. Lowe (Locke on Human Understanding [1995], Ch.7)
Book Reference
Lowe,E.J.: 'Locke on Human Understanding' [Routledge 2004], p.163
A Reaction
We see resemblance between faces instantly, long before we can specify the 'respects' of the resemblance. This supports the Humean hard-wired view of resemblance, rather than some appeal to Platonic universals.