6 ideas
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] |
12812 | Things have real essences, but we categorise them according to the ideas we receive [Locke] |
3597 | Foundations need not precede other beliefs [Wittgenstein] |
3596 | Total doubt can't even get started [Wittgenstein, by Williams,M] |
4721 | If you are not certain of any fact, you cannot be certain of the meaning of your words either [Wittgenstein] |