Full Idea
The grue problem illustrates the enormous importance that the concept of a natural-kind plays in real science.
Gist of Idea
The grue problem shows that natural kinds are central to science
Source
Rom Harré (Laws of Nature [1993], 5)
Book Reference
Harré,Rom: 'Laws of Nature' [Duckworth 1993], p.105
A Reaction
The point is that we took emeralds to be a natural kind, but 'grue' proposes that they aren't, since stability is the hallmark of a natural kind.
Related Idea
Idea 8153 By knowing one piece of clay or gold, you know all of clay or gold [Anon (Upan)]