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] |
1556 | By nature people are close to one another, but culture drives them apart [Hippias] |
20698 | Irenaeus says evil is necessary for perfect human development [Irenaeus, by Davies,B] |