11 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] |
| 22593 | Our sensation of light may not be the same as what produces the sensation [Descartes] |
| 16569 | The Hot, Cold, Wet and Dry of the philosophers need themselves to be explained [Descartes] |
| 20964 | Descartes said there was conservation of 'quantity of motion' [Descartes, by Papineau] |
| 6011 | There is a remote first god (the Good), and a second god who organises the material world [Numenius, by O'Meara] |