Full Idea
Resemblance Nominalism cannot explain the fact that we know when and in what way new objects resemble old ones, and that we know when and in what ways new objects do not resemble old ones.
Gist of Idea
Resemblance Nominalism cannot explain either new resemblances, or absence of resemblances
Source
Cynthia Macdonald (Varieties of Things [2005], Ch.6)
Book Reference
Macdonald,Cynthia: 'Varieties of Things' [Blackwell 2005], p.230
A Reaction
It is not clear what sort of theory would be needed to 'explain' such a thing. Unless there is an explanation of resemblance waiting in the wings (beyond asserting that resemblance is a universal), then this is not a strong objection.