16 ideas
| 14352 | '¬', '&', and 'v' are truth functions: the truth of the compound is fixed by the truth of the components [Jackson] |
| 21354 | It may be that internal relations like proportion exist, because we directly perceive it [MacBride] |
| 21353 | Internal relations are fixed by existences, or characters, or supervenience on characters [MacBride] |
| 21352 | 'Multigrade' relations are those lacking a fixed number of relata [MacBride] |
| 13768 | Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington] |
| 14360 | Possible worlds for subjunctives (and dispositions), and no-truth for indicatives? [Jackson] |
| 13770 | There are many different conditional mental states, and different conditional speech acts [Edgington] |
| 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] |
| 13764 | Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington] |
| 13765 | 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington] |
| 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] |