41 ideas
21463 | Hamann, Herder and Jacobi were key opponents of the Enlightenment [Gardner] |
21459 | Kant halted rationalism, and forced empiricists to worry about foundations [Gardner] |
21460 | Only Kant and Hegel have united nature, morals, politics, aesthetics and religion [Gardner] |
21443 | Transcendental proofs derive necessities from possibilities (e.g. possibility of experiencing objects) [Gardner] |
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] |
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] |
21444 | Modern geoemtry is either 'pure' (and formal), or 'applied' (and a posteriori) [Gardner] |
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] |
21453 | Leibnizian monads qualify as Kantian noumena [Gardner] |
7337 | In Mosaic legal theory, crimes are sins and sins are crimes [Johnson,P] |
7339 | Because human life is what is sacred, Mosaic law has no death penalty for property violations [Johnson,P] |
7353 | The Pharisees undermined slavery, by giving slaves responsibility and status in law courts [Johnson,P] |
7340 | Mosaic law was the first to embody the rule of law, and equality before the law [Johnson,P] |
7338 | Man's life is sacred, because it is made in God's image [Johnson,P] |
7348 | The Jews sharply distinguish human and divine, but the Greeks pull them closer together [Johnson,P] |
7336 | A key moment is the idea of a single moral God, who imposes his morality on humanity [Johnson,P] |
7341 | Sampson illustrates the idea that religious heroes often begin as outlaws and semi-criminals [Johnson,P] |
7342 | Isaiah moved Israelite religion away from the local, onto a more universal plane [Johnson,P] |
7355 | The Torah pre-existed creation, and was its blueprint [Johnson,P] |
7344 | Judaism involves circumcision, Sabbath, Passover, Pentecost, Tabernacles, New Year, and Atonement [Johnson,P] |
7345 | In exile the Jews became a nomocracy [Johnson,P] |
7347 | Zoroastrians believed in one eternal beneficent being, Creator through the holy spirit [Johnson,P] |
7349 | Immortality based on judgement of merit was developed by the Egyptians (not the Jews) [Johnson,P] |
7354 | The main doctrine of the Pharisees was belief in resurrection and the afterlife [Johnson,P] |
7356 | Pious Jews saw heaven as a vast library [Johnson,P] |