Full Idea
It may be that F applies truly to a because F is a determinable predicate satisfied by a's possession of a property answering to a determinate of that determinable predicate.
Gist of Idea
In Fa, F may not be a property of a, but a determinable, satisfied by some determinate
Source
John Heil (The Universe as We Find It [2012], 08.01)
Book Reference
Heil,John: 'The Universe as We Find It' [OUP 2012], p.152
A Reaction
Heil aims to break the commitment of predicates to the existence of properties. The point is that there is no property 'coloured' to correspond to 'a is coloured'. Red might be the determinate that does the job. Nice.