5 ideas
7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
10269 | Mathematics eliminates possibility, as being simultaneous actuality in sets [Putnam] |
541 | Virtue comes more from habit than character [Critias] |
542 | Fear of the gods was invented to discourage secret sin [Critias] |