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] |
| 15119 | Aristotelian explanation by essence may need to draw on knowledge of other essences [Aristotle, by Koslicki] |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| 23302 | Plants have far less life than animals, but more life than other corporeal entities [Aristotle] |
| 23301 | There is a gradual proceeding from the inanimate to animals, with no clear borderlines [Aristotle] |