42 ideas
| 6267 | A culture needs to admit that knowledge is more extensive than just 'science' [Putnam] |
| 6272 | 'True' and 'refers' cannot be made scientically precise, but are fundamental to science [Putnam] |
| 6276 | 'The rug is green' might be warrantedly assertible even though the rug is not green [Putnam] |
| 6266 | We need the correspondence theory of truth to understand language and science [Putnam] |
| 6277 | Correspondence between concepts and unconceptualised reality is impossible [Putnam] |
| 6264 | In Tarski's definition, you understand 'true' if you accept the notions of the object language [Putnam] |
| 6265 | Tarski has given a correct account of the formal logic of 'true', but there is more to the concept [Putnam] |
| 6269 | Only Tarski has found a way to define 'true' [Putnam] |
| 13520 | A 'tautology' must include connectives [Wolf,RS] |
| 13524 | Deduction Theorem: T∪{P}|-Q, then T|-(P→Q), which justifies Conditional Proof [Wolf,RS] |
| 13521 | Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS] |
| 13522 | Universal Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [Wolf,RS] |
| 13523 | Existential Generalization (or 'proof by example'): if we can say P(t), then we can say something is P [Wolf,RS] |
| 13529 | Empty Set: ∃x∀y ¬(y∈x). The unique empty set exists [Wolf,RS] |
| 13526 | Comprehension Axiom: if a collection is clearly specified, it is a set [Wolf,RS] |
| 13534 | In first-order logic syntactic and semantic consequence (|- and |=) nicely coincide [Wolf,RS] |
| 13535 | First-order logic is weakly complete (valid sentences are provable); we can't prove every sentence or its negation [Wolf,RS] |
| 13519 | Model theory uses sets to show that mathematical deduction fits mathematical truth [Wolf,RS] |
| 13531 | Model theory reveals the structures of mathematics [Wolf,RS] |
| 13532 | Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS] |
| 13533 | First-order model theory rests on completeness, compactness, and the Löwenheim-Skolem-Tarski theorem [Wolf,RS] |
| 13537 | An 'isomorphism' is a bijection that preserves all structural components [Wolf,RS] |
| 13539 | The LST Theorem is a serious limitation of first-order logic [Wolf,RS] |
| 13538 | If a theory is complete, only a more powerful language can strengthen it [Wolf,RS] |
| 13525 | Most deductive logic (unlike ordinary reasoning) is 'monotonic' - we don't retract after new givens [Wolf,RS] |
| 13530 | An ordinal is an equivalence class of well-orderings, or a transitive set whose members are transitive [Wolf,RS] |
| 13518 | Modern mathematics has unified all of its objects within set theory [Wolf,RS] |
| 6280 | Realism is a theory, which explains the convergence of science and the success of language [Putnam] |
| 6284 | If a tautology is immune from revision, why would that make it true? [Putnam] |
| 6273 | Knowledge depends on believing others, which must be innate, as inferences are not strong enough [Putnam] |
| 6274 | Empathy may not give knowledge, but it can give plausibility or right opinion [Putnam] |
| 17084 | You can't decide which explanations are good if you don't attend to the interest-relative aspects [Putnam] |
| 6282 | Theory of meaning presupposes theory of understanding and reference [Putnam] |
| 6281 | Truth conditions can't explain understanding a sentence, because that in turn needs explanation [Putnam] |
| 6278 | We should reject the view that truth is prior to meaning [Putnam] |
| 6271 | How reference is specified is not what reference is [Putnam] |
| 6268 | The claim that scientific terms are incommensurable can be blocked if scientific terms are not descriptions [Putnam] |
| 6279 | A private language could work with reference and beliefs, and wouldn't need meaning [Putnam] |
| 6270 | The correct translation is the one that explains the speaker's behaviour [Putnam] |
| 6283 | Language maps the world in many ways (because it maps onto other languages in many ways) [Putnam] |
| 6275 | You can't say 'most speaker's beliefs are true'; in some areas this is not so, and you can't count beliefs [Putnam] |
| 16689 | The schools said spirits lack extension, and wonder how many could dance on a needle's point [More,H] |