Full Idea
All real forms of Nominalism should hold that the only objects relevant to the explanation of generality are concrete particulars, words (i.e. word-tokens, not word-types), and perhaps sets.
Gist of Idea
Real Nominalism is only committed to concrete particulars, word-tokens, and (possibly) sets
Source
Cynthia Macdonald (Varieties of Things [2005], Ch.6 n16)
Book Reference
Macdonald,Cynthia: 'Varieties of Things' [Blackwell 2005], p.255
A Reaction
The addition of sets seems controversial (see Idea 7970). The context is her rejection of the use of tropes in nominalist theories. I would doubt whether a theory still counted as nominalist if it admitted sets (e.g. Quine).
Related Idea
Idea 7670 Kant is the father of the notion of exploitation as an evil [Kant, by Berlin]