30 ideas
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] |
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] |
6871 | We can't only believe things if we are currently conscious of their justification - there are too many [Goldman] |
6872 | Internalism must cover Forgotten Evidence, which is no longer retrievable from memory [Goldman] |
6874 | Internal justification needs both mental stability and time to compute coherence [Goldman] |
8845 | An experience's having propositional content doesn't make it a belief [Pryor] |
8842 | The best argument for immediate justification is not the Regress Argument, but considering examples [Pryor] |
8843 | Impure coherentists accept that perceptions can justify, unlike pure coherentists [Pryor] |
8844 | Coherentism rests on the claim that justifications must be beliefs, with propositional content [Pryor] |
8846 | Reasons for beliefs can be cited to others, unlike a raw headache experience [Pryor] |
6873 | Coherent justification seems to require retrieving all our beliefs simultaneously [Goldman] |
6875 | Reliability involves truth, and truth is external [Goldman] |
8847 | Beliefs are not chosen, but you can seek ways to influence your belief [Pryor] |