8 ideas
7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
21566 | 'Propositional functions' are ambiguous until the variable is given a value [Russell] |
21567 | 'All judgements made by Epimenedes are true' needs the judgements to be of the same type [Russell] |
23457 | Type theory cannot identify features across levels (because such predicates break the rules) [Morris,M on Russell] |
21556 | Classes are defined by propositional functions, and functions are typed, with an axiom of reducibility [Russell, by Lackey] |
21568 | A one-variable function is only 'predicative' if it is one order above its arguments [Russell] |
11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
12709 | Motion is not absolute, but consists in relation [Leibniz] |