37 ideas
| 13966 | Analytic philosophy loved the necessary a priori analytic, linguistic modality, and rigour [Soames] |
| 13974 | If philosophy is analysis of meaning, available to all competent speakers, what's left for philosophers? [Soames] |
| 13520 | A 'tautology' must include connectives [Wolf,RS] |
| 13524 | Deduction Theorem: T∪{P}|-Q, then T|-(P→Q), which justifies Conditional Proof [Wolf,RS] |
| 13522 | Universal Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [Wolf,RS] |
| 13521 | Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS] |
| 13523 | Existential Generalization (or 'proof by example'): if we can say P(t), then we can say something is P [Wolf,RS] |
| 15163 | The interest of quantified modal logic is its metaphysical necessity and essentialism [Soames] |
| 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] |
| 15158 | Indefinite descriptions are quantificational in subject position, but not in predicate position [Soames] |
| 15157 | Recognising the definite description 'the man' as a quantifier phrase, not a singular term, is a real insight [Soames] |
| 15156 | The universal and existential quantifiers were chosen to suit mathematics [Soames] |
| 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] |
| 13519 | Model theory uses sets to show that mathematical deduction fits mathematical truth [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] |
| 13969 | Kripkean essential properties and relations are necessary, in all genuinely possible worlds [Soames] |
| 15162 | We understand metaphysical necessity intuitively, from ordinary life [Soames] |
| 15161 | There are more metaphysically than logically necessary truths [Soames] |
| 13973 | A key achievement of Kripke is showing that important modalities are not linguistic in source [Soames] |
| 13968 | Kripkean possible worlds are abstract maximal states in which the real world could have been [Soames] |
| 15152 | To study meaning, study truth conditions, on the basis of syntax, and representation by the parts [Soames] |
| 15153 | Tarski's account of truth-conditions is too weak to determine meanings [Soames] |
| 13965 | Semantics as theory of meaning and semantics as truth-based logical consequence are very different [Soames] |
| 13964 | Semantic content is a proposition made of sentence constituents (not some set of circumstances) [Soames] |
| 13972 | Two-dimensionalism reinstates descriptivism, and reconnects necessity and apriority to analyticity [Soames] |
| 15154 | We should use cognitive states to explain representational propositions, not vice versa [Soames] |
| 3029 | Stilpo said if Athena is a daughter of Zeus, then a statue is only the child of a sculptor, and so is not a god [Stilpo, by Diog. Laertius] |