Full Idea
Nominalists have the major task of explaining how predicates work. They usually construct it as a relation between individuals, or deny the referential function of predicates.
Gist of Idea
Nominalists say predication is relations between individuals, or deny that it refers
Source
Ruth Barcan Marcus (Nominalism and Substitutional Quantifiers [1978], p.163)
Book Reference
'Philosophy of Logic: an anthology', ed/tr. Jacquette,Dale [Blackwell 2002], p.163