11 ideas
7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
11211 | If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt] |
12219 | Whether a modal claim is true depends on how the object is described [Quine, by Fine,K] |
11212 | The sense of a connective comes from primitively obvious rules of inference [Rumfitt] |
11210 | Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt] |
10922 | Objects are the values of variables, so a referentially opaque context cannot be quantified into [Quine] |
10923 | Aristotelian essentialism says a thing has some necessary and some non-necessary properties [Quine] |
11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
10921 | Necessity can attach to statement-names, to statements, and to open sentences [Quine] |
10924 | Necessity is in the way in which we say things, and not things themselves [Quine] |
11214 | We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt] |