5 ideas
7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
9879 | NF has no models, but just blocks the comprehension axiom, to avoid contradictions [Quine, by Dummett] |
579 | Cratylus said you couldn't even step into the same river once [Cratylus, by Aristotle] |
11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
578 | Cratylus decided speech was hopeless, and his only expression was the movement of a finger [Cratylus, by Aristotle] |