18 ideas
13838 | A decent modern definition should always imply a semantics [Hacking] |
13833 | 'Thinning' ('dilution') is the key difference between deduction (which allows it) and induction [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] |
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] |
6402 | In 1927, Russell analysed force and matter in terms of events [Russell, by Grayling] |
14732 | A perceived physical object is events grouped around a centre [Russell] |
14733 | An object produces the same percepts with or without a substance, so that is irrelevant to science [Russell] |
19696 | There are reasons 'for which' a belief is held, reasons 'why' it is believed, and reasons 'to' believe it [Neta] |
19697 | The basing relation of a reason to a belief should both support and explain the belief [Neta] |
6418 | Russell rejected phenomenalism because it couldn't account for causal relations [Russell, by Grayling] |
21706 | At first matter is basic and known by sense-data; later Russell says matter is constructed [Russell, by Linsky,B] |