Full Idea
The applicability of 'grue' to each of a pair of particulars does not guarantee the similarity of those particulars.
Gist of Idea
Two applications of 'grue' do not guarantee a similarity between two things
Source
Theodore Sider (Writing the Book of the World [2011], 06.2)
Book Reference
Sider,Theodore: 'Writing the Book of the World' [OUP 2011], p.89
A Reaction
Grue is not a colour but a behaviour. If two things are 'mercurial' or 'erratic', will that ensure a similarity at any given moment?