17 ideas
15970 | People generalise because it is easier to understand, and that is mistaken for deep philosophy [Feynman] |
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] |
12739 | If we are dreaming, it is sufficient that the events are coherent, and obey laws [Leibniz] |
12738 | Successful prediction shows proficiency in nature [Leibniz] |
9410 | Physical Laws are rhythms and patterns in nature, revealed by analysis [Feynman] |
18530 | Nobody understands quantum mechanics [Feynman] |
17707 | We should regard space as made up of many tiny pieces [Feynman, by Mares] |