4 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] |
10009 | Substitutional quantification is just a variant of Tarski's account [Wallace, by Baldwin] |
5960 | When the soul is intelligent and harmonious, it is part of god and derives from god [Plutarch] |