58 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] |
| 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] |
| 23101 | Intuitions don't prove things; they just receptivity to interpretations [Kekes] |
| 23086 | Liberals say we are only responsible for fully autonomous actions [Kekes] |
| 23100 | Collective responsibility conflicts with responsibility's requirement of authonomy [Kekes] |
| 23093 | Moral and causal responsibility are not clearly distinct [Kekes] |
| 23096 | Morality should aim to prevent all evil actions, not just autonomous ones [Kekes] |
| 23087 | Much human evil is not autonomous, so moral responsibility need not be autonomous [Kekes] |
| 23098 | Effects show the existence of moral responsibility, and mental states show the degree [Kekes] |
| 23089 | Evil people may not be autonomously aware, if they misjudge the situation [Kekes] |
| 23094 | Ought implies can means moral responsibility needs autonomy [Kekes] |
| 23095 | Why should moral responsibility depend on autonomy, rather than social role or experience? [Kekes] |
| 23090 | Liberals assume people are naturally free, equal, rational, and morally good [Kekes] |
| 6017 | Nomos is king [Pindar] |
| 23117 | Love should be partial, and discriminate in favour of its object [Kekes] |
| 23119 | Sentimental love distorts its object [Kekes] |
| 23088 | Evil is not deviation from the good, any more than good is a deviation from evil [Kekes] |
| 23097 | What matters for morality is the effects of action, not the psychological causes [Kekes] |
| 23099 | It is said that if an agent is not autonomous then their evil actions don't reflect on their character [Kekes] |
| 23118 | Awareness of others' suffering doesn't create an obligation to help [Kekes] |
| 23109 | The veil of ignorance is only needed because people have bad motivations [Kekes] |
| 23114 | The chief function of the state is to arbitrate between contending visions of the good life [Kekes] |
| 23116 | Citizenship is easier than parenthood [Kekes] |
| 23103 | Power is meant to be confined to representatives, and subsequent delegation [Kekes] |
| 23107 | Prosperity is a higher social virtue than justice [Kekes] |
| 23081 | Liberal basics are pluralism, freedom, rights, equality, and distributive justice - for autonomy [Kekes] |
| 23085 | The key liberal values are explained by the one core value, which is autonomy [Kekes] |
| 23092 | Agents have little control over the capacities needed for liberal autonomy [Kekes] |
| 23102 | Liberals are egalitarians, but in varying degrees [Kekes] |
| 23084 | Are egalitarians too coercive, or not egalitarian enough, or lax over morality? [Kekes] |
| 23079 | Liberal justice ignores desert, which is the essence of justice [Kekes] |
| 23091 | Why do liberals not see a much wider range of values as basic? [Kekes] |
| 23112 | Liberals ignore contingency, and think people are good and equal, and institutions cause evil [Kekes] |
| 23082 | Liberal distribution cares more about recipients than donors [Kekes] |
| 23106 | To rectify the undeserved equality, we should give men longer and women shorter lives [Kekes] |
| 23121 | It is just a fact that some people are morally better than others [Kekes] |
| 23105 | It is not deplorable that billionaires have more than millionaires [Kekes] |
| 23120 | The problem is basic insufficiency of resources, not their inequality [Kekes] |
| 23108 | Justice combines consistency and desert; treat likes alike, judging likeness by desert [Kekes] |
| 23083 | Liberal welfare focuses on need rather than desert [Kekes] |
| 23113 | Sexual morality doesn't require monogamy, but it needs a group of sensible regulations [Kekes] |