more from this thinker | more from this text
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
Source
David Lewis (Parts of Classes [1991], 2.1)
Book Ref
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.
| 15510 | Classes are a host of ethereal, platonic, pseudo entities [Goodman] |
| 7785 | The use of plurals doesn't commit us to sets; there do not exist individuals and collections [Boolos] |
| 15508 | If singletons are where their members are, then so are all sets [Lewis] |
| 15514 | A huge part of Reality is only accepted as existing if you have accepted set theory [Lewis] |
| 15523 | Set theory isn't innocent; it generates infinities from a single thing; but mathematics needs it [Lewis] |
| 13631 | Are sets part of logic, or part of mathematics? [Shapiro] |
| 9549 | The set theorist cannot tell us what 'membership' is [Chihara] |
| 10109 | ZFC can prove that there is no set corresponding to the concept 'set' [George/Velleman] |