15 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] |
| 12219 | Whether a modal claim is true depends on how the object is described [Quine, by Fine,K] |
| 9195 | Intuitionists reject excluded middle, not for a third value, but for possibility of proof [Dummett] |
| 10922 | Objects are the values of variables, so a referentially opaque context cannot be quantified into [Quine] |
| 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] |
| 14979 | Being alone doesn't guarantee intrinsic properties; 'being alone' is itself extrinsic [Lewis, by Sider] |
| 15454 | Extrinsic properties come in degrees, with 'brother' less extrinsic than 'sibling' [Lewis] |
| 15455 | Total intrinsic properties give us what a thing is [Lewis] |
| 10923 | Aristotelian essentialism says a thing has some necessary and some non-necessary properties [Quine] |
| 10921 | Necessity can attach to statement-names, to statements, and to open sentences [Quine] |
| 10924 | Necessity is in the way in which we say things, and not things themselves [Quine] |