32 ideas
| 13838 | A decent modern definition should always imply a semantics [Hacking] |
| 13834 | Gentzen's Cut Rule (or transitivity of deduction) is 'If A |- B and B |- C, then A |- C' [Hacking] |
| 13835 | Only Cut reduces complexity, so logic is constructive without it, and it can be dispensed with [Hacking] |
| 13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [Hacking] |
| 13845 | The various logics are abstractions made from terms like 'if...then' in English [Hacking] |
| 13840 | First-order logic is the strongest complete compact theory with Löwenheim-Skolem [Hacking] |
| 13844 | A limitation of first-order logic is that it cannot handle branching quantifiers [Hacking] |
| 13842 | Second-order completeness seems to need intensional entities and possible worlds [Hacking] |
| 13837 | With a pure notion of truth and consequence, the meanings of connectives are fixed syntactically [Hacking] |
| 13839 | Perhaps variables could be dispensed with, by arrows joining places in the scope of quantifiers [Hacking] |
| 13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
| 20660 | At one level maths and nature are very similar, suggesting some deeper origin [Wolfram] |
| 23125 | Most good social changes are incremental, rather than revolutionary [Gopnik] |
| 23126 | Conservatives often want peace, prosperity and tolerance, but not social fairness [Gopnik] |
| 23132 | Conservatives believe obedience and rank are essential to social order [Gopnik] |
| 23128 | The opposite of liberalism is dogmatism [Gopnik] |
| 23142 | People are fallible, so liberalism tries to distribute power [Gopnik] |
| 23143 | Liberals have tried very hard to build a conscience into their institutions [Gopnik] |
| 23141 | Left-wingers are inconsistent in their essentialist descriptions of social groups [Gopnik] |
| 23124 | Liberal community is not blood ties or tradition, but shared choices, and sympathy for the losers [Gopnik] |
| 23127 | Liberal community includes flight from the family, into energetic reforming groups [Gopnik] |
| 23138 | Modern left-wingers criticise liberalism's control of culture [Gopnik] |
| 23129 | Right-wingers attack liberal faith in reason, left-wingers attack its faith in reform [Gopnik] |
| 23133 | Cosmopolitan liberals lack national loyalty, and welcome excessive immigration [Gopnik] |
| 23139 | Liberalism's attempt to be neutral and colour-blind erases cultural identities [Gopnik] |
| 23135 | Classic Marxists see liberalism as the ideology of the bourgeoisie [Gopnik] |
| 23140 | Environmental disasters result not from capitalism, but from a general drive for growth [Gopnik] |
| 23130 | Popular imperialism gives the poor the belief that their acts have world historical meaning [Gopnik] |
| 23131 | Patriots love their place, but nationalists have a paranoid ethnic hostility [Gopnik] |
| 23136 | Liberal free speech is actually paid speech [Gopnik] |
| 23134 | A 'free' society implies a free market, which always produces predatory capitalism and inequalities [Gopnik] |
| 20659 | Space and its contents seem to be one stuff - so space is the only existing thing [Wolfram] |