|Abstraction: Subsumption of objects by non-consideration of certain properties. See also equivalence relation, concretion, concreta, indiscernibility.|
|Geach, Peter T.
Books on Amazon
Abstraction / FregeVs: mere abstraction of differences does not create (identical) properties - Geach: E.g. Def "surmen" are identical if their surnames are identical - so that is actually a subset of people, but the same man when abstracted from differences - GeachVs: that would not explain the word "surman" - Solution / Quine: "Tangibility": properties had little sense when you used "red" etc. only as names of properties - GeachVsQuine: then we get all the problems with classes: E.g. "The property, to be a prop that does not apply to itself" - would be parallel to Russell’s antinomy.
Logic Matters Oxford 1972