41 ideas
22358 | Scientific objectivity lies in inter-subjective testing [Popper] |
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] |
16668 | Modes of things exist in some way, without being full-blown substances [Gassendi] |
16730 | If matter is entirely atoms, anything else we notice in it can only be modes [Gassendi] |
11946 | Propensities are part of a situation, not part of the objects [Popper] |
12177 | Human artefacts may have essences, in their purposes [Popper] |
5451 | Popper felt that ancient essentialism was a bar to progress [Popper, by Mautner] |
18284 | Particulars can be verified or falsified, but general statements can only be falsified (conclusively) [Popper] |
22188 | Give Nobel Prizes for really good refutations? [Gorham on Popper] |
7780 | Falsification is the criterion of demarcation between science and non-science [Popper, by Magee] |
16830 | We don't only reject hypotheses because we have falsified them [Lipton on Popper] |
6794 | If falsification requires logical inconsistency, then probabilistic statements can't be falsified [Bird on Popper] |
6795 | When Popper gets in difficulties, he quietly uses induction to help out [Bird on Popper] |
3856 | Good theories have empirical content, explain a lot, and are not falsified [Popper, by Newton-Smith] |
7779 | There is no such thing as induction [Popper, by Magee] |
3860 | Science cannot be shown to be rational if induction is rejected [Newton-Smith on Popper] |
16619 | We observe qualities, and use 'induction' to refer to the substances lying under them [Gassendi] |
12176 | Science does not aim at ultimate explanations [Popper] |
3400 | Things must have parts to intermingle [Gassendi] |
16593 | Atoms are not points, but hard indivisible things, which no force in nature can divide [Gassendi] |
16729 | How do mere atoms produce qualities like colour, flavour and odour? [Gassendi] |
12175 | Galilean science aimed at true essences, as the ultimate explanations [Popper] |
12179 | Essentialist views of science prevent further questions from being raised [Popper] |