18 ideas
6222 | If a decision is in accord with right reason, everyone can agree with it [Cumberland] |
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] |
17751 | Gödel proved the completeness of first order predicate logic in 1930 [Gödel, by Walicki] |
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] |
6217 | Natural law is supplied to the human mind by reality and human nature [Cumberland] |
6221 | If there are different ultimate goods, there will be conflicting good actions, which is impossible [Cumberland] |
6218 | The happiness of individuals is linked to the happiness of everyone (which is individuals taken together) [Cumberland] |
6220 | The happiness of all contains the happiness of each, and promotes it [Cumberland] |
6216 | Natural law is immutable truth giving moral truths and duties independent of society [Cumberland] |