5 ideas
| 11074 | 'It is true that this follows' means simply: this follows [Wittgenstein] |
| 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] |
| 11073 | Two and one making three has the necessity of logical inference [Wittgenstein] |
| 6019 | If someone squashed a horse to make a dog, something new would now exist [Mnesarchus] |