display all the ideas for this combination of texts
4 ideas
8078 | Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin] |
6023 | Every proposition is either true or false [Chrysippus, by Cicero] |
13427 | Either 'a = b' vacuously names the same thing, or absurdly names different things [Ramsey] |
13334 | Contradictions are either purely logical or mathematical, or they involved thought and language [Ramsey] |