7 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] |
| 8526 | We might treat both tropes and substances as fundamental, so we can't presume it is just tropes [Daly] |
| 8527 | More than one trope (even identical ones!) can occupy the same location [Daly] |
| 8528 | If tropes are linked by the existence of concurrence, a special relation is needed to link them all [Daly] |
| 14790 | 'Abduction' is beginning a hypothesis, particularly if it includes preference of one explanation over others [Peirce] |
| 14791 | Abduction involves original suggestions, and not just the testing involved in induction [Peirce] |