Full Idea
Using the predicate '...is exactly similar to...' we can sort tropes into equivalence sets, these sets serving as properties and relations. For example, the property of redness is the maximal set of the tropes of redness.
Gist of Idea
The property of redness is the maximal set of the tropes of exactly similar redness
Source
Alex Oliver (The Metaphysics of Properties [1996], §12)
Book Reference
-: 'Mind' [-], p.34
A Reaction
You have somehow to get from scarlet and vermilion, which have exact similarity within their sets, to redness, which doesn't.