16 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] |
15566 | Events are classes, and so there is a mereology of their parts [Lewis] |
15567 | Some events involve no change; they must, because causal histories involve unchanges [Lewis] |
15561 | The events that suit semantics may not be the events that suit causation [Lewis] |
15565 | Events have inbuilt essences, as necessary conditions for their occurrence [Lewis] |
15564 | An event is a property of a unique space-time region [Lewis] |
15563 | Properties are very abundant (unlike universals), and are used for semantics and higher-order variables [Lewis] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
15562 | Causation is a general relation derived from instances of causal dependence [Lewis] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |