23 ideas
8092 | Logic was merely a branch of rhetoric until the scientific 17th century [Devlin] |
8081 | 'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin] |
8085 | Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin] |
8086 | Predicate logic retains the axioms of propositional logic [Devlin] |
8091 | Situation theory is logic that takes account of context [Devlin] |
8089 | Montague's intensional logic incorporated the notion of meaning [Devlin] |
8087 | Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin] |
8082 | Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin] |
8072 | Sentences of apparent identical form can have different contextual meanings [Devlin] |
14352 | '¬', '&', and 'v' are truth functions: the truth of the compound is fixed by the truth of the components [Jackson] |
8075 | Space and time are atomic in the arrow, and divisible in the tortoise [Devlin] |
14360 | Possible worlds for subjunctives (and dispositions), and no-truth for indicatives? [Jackson] |
14353 | Modus ponens requires that A→B is F when A is T and B is F [Jackson] |
14354 | When A and B have the same truth value, A→B is true, because A→A is a logical truth [Jackson] |
14355 | (A&B)→A is a logical truth, even if antecedent false and consequent true, so it is T if A is F and B is T [Jackson] |
14358 | In the possible worlds account of conditionals, modus ponens and modus tollens are validated [Jackson] |
14359 | Only assertions have truth-values, and conditionals are not proper assertions [Jackson] |
14357 | Possible worlds account, unlike A⊃B, says nothing about when A is false [Jackson] |
14356 | We can't insist that A is relevant to B, as conditionals can express lack of relevance [Jackson] |
8088 | People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin] |
8073 | How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin] |
8076 | The distinction between sentences and abstract propositions is crucial in logic [Devlin] |
20239 | Unlike us, the early Greeks thought envy was a good thing, and hope a bad thing [Hesiod, by Nietzsche] |