33 ideas
7990 | Serene wisdom is freedom from ties, and indifference to fortune [Anon (Bhag)] |
7989 | Seek salvation in the wisdom of reason [Anon (Bhag)] |
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] |
7996 | I am all the beauty and goodness of things, says Krishna [Anon (Bhag)] |
14082 | No sortal could ever exactly pin down which set of particles count as this 'cup' [Schaffer,J] |
14081 | Identities can be true despite indeterminate reference, if true under all interpretations [Schaffer,J] |
7995 | In all living beings I am the light of consciousness, says Krishna [Anon (Bhag)] |
7999 | All actions come from: body, lower self, perception, means of action, or Fate [Anon (Bhag)] |
7991 | Hate and lust have their roots in man's lower nature [Anon (Bhag)] |
7988 | There is no greater good for a warrior than to fight in a just war [Anon (Bhag)] |
7992 | The visible forms of nature are earth, water, fire, air, ether; mind, reason, and the sense of 'I' [Anon (Bhag)] |
7994 | Everything, including the gods, comes from me, says Krishna [Anon (Bhag)] |
7993 | Brahman is supreme, Atman his spirit in man, and Karma is the force of creation [Anon (Bhag)] |
7997 | Only by love can men see me, know me, and come to me, says Krishna [Anon (Bhag)] |
7998 | The three gates of hell are lust, anger and greed [Anon (Bhag)] |