10 ideas
17750 | The first clear proof of the consistency of the first order predicate logic was in 1928 [Hilbert/Ackermann, by Walicki] |
18755 | Validity is explained as truth in all models, because that relies on the logical terms [McGee] |
18751 | Natural language includes connectives like 'because' which are not truth-functional [McGee] |
18761 | Second-order variables need to range over more than collections of first-order objects [McGee] |
18753 | An ontologically secure semantics for predicate calculus relies on sets [McGee] |
18754 | Logically valid sentences are analytic truths which are just true because of their logical words [McGee] |
18757 | Soundness theorems are uninformative, because they rely on soundness in their proofs [McGee] |
18760 | The culmination of Euclidean geometry was axioms that made all models isomorphic [McGee] |
5997 | Dicaearchus said soul does not exist, but is just a configuration of the body [Dicaearchus, by Fortenbaugh] |
18762 | A maxim claims that if we are allowed to assert a sentence, that means it must be true [McGee] |