14 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] |
| 11993 | Jones may cease to exist without some simple property, but that doesn't make it essential [Kung] |
| 11997 | A property may belong essentially to one thing and contingently to another [Kung] |
| 11992 | Aristotelian essences underlie a thing's existence, explain it, and must belong to it [Kung] |
| 7458 | The reliability of witnesses depends on whether they benefit from their observations [Laplace, by Hacking] |
| 11995 | Some peripheral properties are explained by essential ones, but don't themselves explain properties [Kung] |
| 11996 | Some non-essential properties may explain more than essential-but-peripheral ones do [Kung] |
| 3441 | If a supreme intellect knew all atoms and movements, it could know all of the past and the future [Laplace] |