19 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] |
17505 | Using proper names properly doesn't involve necessary and sufficient conditions [Putnam] |
13843 | If it is a logic, the Löwenheim-Skolem theorem holds for it [Hacking] |
11908 | Putnam bases essences on 'same kind', but same kinds may not share properties [Mackie,P on Putnam] |
17508 | Science aims at truth, not at 'simplicity' [Putnam] |
17506 | I now think reference by the tests of experts is a special case of being causally connected [Putnam] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
11904 | Express natural kinds as a posteriori predicate connections, not as singular terms [Putnam, by Mackie,P] |
17507 | Natural kind stereotypes are 'strong' (obvious, like tiger) or 'weak' (obscure, like molybdenum) [Putnam] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |