12 ideas
8207 | The quest for simplicity drove scientists to posit new entities, such as molecules in gases [Quine] |
8208 | In arithmetic, ratios, negatives, irrationals and imaginaries were created in order to generalise [Quine] |
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] |
8205 | Explaining events just by bodies can't explain two events identical in space-time [Quine] |
490 | Everything happens by reason and necessity [Leucippus] |
8206 | Necessity could be just generalisation over classes, or (maybe) quantifying over possibilia [Quine] |