19 ideas
8378 | Philosophers usually learn science from each other, not from science [Russell] |
12204 | The logic of metaphysical necessity is S5 [Rumfitt] |
12195 | Soundness in argument varies with context, and may be achieved very informally indeed [Rumfitt] |
12199 | There is a modal element in consequence, in assessing reasoning from suppositions [Rumfitt] |
12201 | We reject deductions by bad consequence, so logical consequence can't be deduction [Rumfitt] |
12194 | Contradictions include 'This is red and not coloured', as well as the formal 'B and not-B' [Rumfitt] |
12198 | Geometrical axioms in logic are nowadays replaced by inference rules (which imply the logical truths) [Rumfitt] |
8375 | 'Necessary' is a predicate of a propositional function, saying it is true for all values of its argument [Russell] |
14532 | A distinctive type of necessity is found in logical consequence [Rumfitt, by Hale/Hoffmann,A] |
12193 | Logical necessity is when 'necessarily A' implies 'not-A is contradictory' [Rumfitt] |
12200 | A logically necessary statement need not be a priori, as it could be unknowable [Rumfitt] |
12202 | Narrow non-modal logical necessity may be metaphysical, but real logical necessity is not [Rumfitt] |
12191 | Counterfactuals are true if logical or natural laws imply the consequence [Goodman, by McFetridge] |
12203 | If a world is a fully determinate way things could have been, can anyone consider such a thing? [Rumfitt] |
4396 | The law of causality is a source of confusion, and should be dropped from philosophy [Russell] |
8376 | If causes are contiguous with events, only the last bit is relevant, or the event's timing is baffling [Russell] |
8380 | Striking a match causes its igniting, even if it sometimes doesn't work [Russell] |
8379 | In causal laws, 'events' must recur, so they have to be universals, not particulars [Russell] |
8381 | The constancy of scientific laws rests on differential equations, not on cause and effect [Russell] |