20 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] |
| 12756 | Substance is a force for acting and being acted upon [Leibniz] |
| 18925 | If talking donkeys are possible, something exists which could be a talking donkey [Williamson, by Cameron] |
| 12755 | Final causes can help with explanations in physics [Leibniz] |
| 12760 | Something rather like souls (though not intelligent) could be found everywhere [Leibniz] |
| 12759 | There are atoms of substance, but no atoms of bulk or extension [Leibniz] |
| 12718 | Secondary matter is active and complete; primary matter is passive and incomplete [Leibniz] |
| 11854 | If there is some trace of God in things, that would explain their natural force [Leibniz] |
| 12758 | It is plausible to think substances contain the same immanent force seen in our free will [Leibniz] |
| 19408 | To say that nature or the one universal substance is God is a pernicious doctrine [Leibniz] |