27 ideas
21544 | It seems that when a proposition is false, something must fail to subsist [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] |
21539 | Excluded middle can be stated psychologically, as denial of p implies assertion of not-p [Russell] |
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] |
21538 | If two people perceive the same object, the object of perception can't be in the mind [Russell] |
21534 | The only thing we can say about relations is that they relate [Russell] |
21540 | Relational propositions seem to be 'about' their terms, rather than about the relation [Russell] |
21536 | When I perceive a melody, I do not perceive the notes as existing [Russell] |
21535 | Objects only exist if they 'occupy' space and time [Russell] |
14532 | A distinctive type of necessity is found in logical consequence [Rumfitt, by Hale/Hoffmann,A] |
12200 | A logically necessary statement need not be a priori, as it could be unknowable [Rumfitt] |
12193 | Logical necessity is when 'necessarily A' implies 'not-A is contradictory' [Rumfitt] |
12202 | Narrow non-modal logical necessity may be metaphysical, but real logical necessity is not [Rumfitt] |
21533 | Contingency arises from tensed verbs changing the propositions to which they refer [Russell] |
12203 | If a world is a fully determinate way things could have been, can anyone consider such a thing? [Rumfitt] |
21537 | I assume we perceive the actual objects, and not their 'presentations' [Russell] |
21532 | Full empiricism is not tenable, but empirical investigation is always essential [Russell] |
21542 | Do incorrect judgements have non-existent, or mental, or external objects? [Russell] |
21541 | The complexity of the content correlates with the complexity of the object [Russell] |
7752 | Only the utterer's primary intention is relevant to the meaning [Grice] |
7751 | Meaning needs an intention to induce a belief, and a recognition that this is the speaker's intention [Grice] |
7753 | We judge linguistic intentions rather as we judge non-linguistic intentions, so they are alike [Grice] |
21543 | If p is false, then believing not-p is knowing a truth, so negative propositions must exist [Russell] |