4 ideas
7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
18948 | There is an object for every set of properties (some of which exist, and others don't) [Parsons,T, by Sawyer] |
11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
4316 | Either all action is rational, or reason dominates, or reason is only concerned with means [Cottingham] |