3 ideas
14235 | Saying 'they can become a set' is a tautology, because reference to 'they' implies a collection [Cargile] |
14248 | We could accept the integers as primitive, then use sets to construct the rest [Cohen] |
20653 | Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson] |