Single Idea 15508

[catalogued under 4. Formal Logic / F. Set Theory ST / 5. Conceptions of Set / a. Sets as existing]

Full Idea

If every singleton was where its member was, then, in general, classes would be where there members were.

Gist of Idea

If singletons are where their members are, then so are all sets


David Lewis (Parts of Classes [1991], 2.1)

Book Reference

Lewis,David: 'Parts of Classes' [Blackwell 1991], p.32

A Reaction

There seems to be a big dislocation of understanding of the nature of sets, between 'pure' set theory, and set theory with ur-elements. I take the pure to be just an 'abstraction' from the more located one. The empty set has a puzzling location.