Single Idea 9389

[catalogued under 9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects]

Full Idea

Vagueness in respect of membership is consistency with determinacy of the set's identity, so long as a set's identity is taken to consist, not in its having such-and-such members, but in its being the extension of a concept.

Gist of Idea

Vague membership of sets is possible if the set is defined by its concept, not its members

Source

Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.5)


A Reaction

I find this view of sets much more appealing than the one that identifies a set with its members. The empty set is less of a problem, as well as non-existents. Logicians prefer the extensional view because it is tidy.