12 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] |
| 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] |
| 18439 | Because things can share attributes, we cannot individuate attributes clearly [Quine] |
| 18442 | You only know an attribute if you know what things have it [Quine] |
| 18441 | No entity without identity (which requires a principle of individuation) [Quine] |
| 18440 | Identity of physical objects is just being coextensive [Quine] |
| 19945 | Jew and Greeks, bond and free, male and female, are all one in Christ [Paul] |