14 ideas
| 9193 | ZF set theory has variables which range over sets, 'equals' and 'member', and extensionality [Dummett] |
| 9194 | The main alternative to ZF is one which includes looser classes as well as sets [Dummett] |
| 9406 | A class is natural when everybody can spot further members of it [Quinton] |
| 9195 | Intuitionists reject excluded middle, not for a third value, but for possibility of proof [Dummett] |
| 9186 | First-order logic concerns objects; second-order adds properties, kinds, relations and functions [Dummett] |
| 9187 | Logical truths and inference are characterized either syntactically or semantically [Dummett] |
| 9191 | Ordinals seem more basic than cardinals, since we count objects in sequence [Dummett] |
| 9192 | The number 4 has different positions in the naturals and the wholes, with the same structure [Dummett] |
| 15730 | Extreme nominalists say all classification is arbitrary convention [Quinton] |
| 15728 | The naturalness of a class depends as much on the observers as on the objects [Quinton] |
| 9407 | Properties imply natural classes which can be picked out by everybody [Quinton] |
| 15729 | Uninstantiated properties must be defined using the instantiated ones [Quinton] |
| 8520 | An individual is a union of a group of qualities and a position [Quinton, by Campbell,K] |
| 7295 | Maybe induction is only reliable IF reality is stable [Mitchell,A] |