Full Idea
Semantics should not employ the relationship of set-membership between objects and extensions, but rather the relation of instantiation between objects and properties.
Clarification
'Instantiation' is there being an actual instance or case of something
Gist of Idea
Semantics should not be based on set-membership, but on instantiation of properties in objects
Source
Colin McGinn (Logical Properties [2000], Ch.3)
Book Reference
McGinn,Colin: 'Logical Properties' [OUP 2003], p.68
A Reaction
At least this means that philosophers won't be required to read fat books on set theory, but they will have to think very carefully about 'instantiation'. A good start is the ideas on 'Partaking' of Platonic Forms in this database (in 'Universals').