Single Idea 17675

[catalogued under 14. Science / C. Induction / 5. Paradoxes of Induction / a. Grue problem]

Full Idea

The predicate 'grue' involves essential reference to a particular time, which 'green' does not. Also on the 'grue' hypothesis a change occurs in emeralds in a way that change does not occur on the 'green' hypothesis.

Gist of Idea

Unlike 'green', the 'grue' predicate involves a time and a change


David M. Armstrong (What is a Law of Nature? [1983], 04.5)

Book Reference

Armstrong,D.M.: 'What is a Law of Nature?' [CUP 1985], p.58

A Reaction

I'm inclined to think that comparing 'grue' with 'green' is a category mistake. 'Grue' is a behaviour. Armstrong says this is no objection, because Goodman's argument is purely formal.