5 ideas
18487 | We want to know what makes sentences true, rather than defining 'true' [McFetridge] |
9565 | Zermelo made 'set' and 'member' undefined axioms [Zermelo, by Chihara] |
3339 | For Zermelo's set theory the empty set is zero and the successor of each number is its unit set [Zermelo, by Blackburn] |
18488 | We normally explain natural events by citing further facts [McFetridge] |
6019 | If someone squashed a horse to make a dog, something new would now exist [Mnesarchus] |