Full Idea
It is plausible to say, on the basis of total science, that 'grue' is a predicate to which no genuine, that is, unitary, universal corresponds.
Gist of Idea
Science suggests that the predicate 'grue' is not a genuine single universal
Source
David M. Armstrong (What is a Law of Nature? [1983], 06.7)
Book Reference
Armstrong,D.M.: 'What is a Law of Nature?' [CUP 1985], p.99