9 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] |
| 9390 | Logic guides thinking, but it isn't a substitute for it [Rumfitt] |
| 9389 | Vague membership of sets is possible if the set is defined by its concept, not its members [Rumfitt] |
| 21315 | A tree remains the same in the popular sense, but not in the strict philosophical sense [Butler] |
| 21317 | Despite consciousness fluctuating, we are aware that it belongs to one person [Butler] |
| 21313 | If consciousness of events makes our identity, then if we have forgotten them we didn't exist then [Butler] |
| 21314 | Consciousness presupposes personal identity, so it cannot constitute it [Butler] |
| 21318 | If the self changes, we have no responsibilities, and no interest in past or future [Butler] |