39 ideas
7920 | Descriptive metaphysics aims at actual structure, revisionary metaphysics at a better structure [Strawson,P] |
7922 | Descriptive metaphysics concerns unchanging core concepts and categories [Strawson,P] |
7921 | Close examination of actual word usage is the only sure way in philosophy [Strawson,P] |
10476 | The idea that groups of concepts could be 'implicitly defined' was abandoned [Hodges,W] |
10842 | The fact which is stated by a true sentence is not something in the world [Strawson,P] |
10843 | Facts aren't exactly true statements, but they are what those statements say [Strawson,P] |
10844 | The statement that it is raining perfectly fits the fact that it is raining [Strawson,P] |
10841 | The word 'true' always refers to a possible statement [Strawson,P] |
10304 | Very few things in set theory remain valid in intuitionist mathematics [Bernays] |
10282 | Logic is the study of sound argument, or of certain artificial languages (or applying the latter to the former) [Hodges,W] |
10478 | Since first-order languages are complete, |= and |- have the same meaning [Hodges,W] |
10477 | |= in model-theory means 'logical consequence' - it holds in all models [Hodges,W] |
8358 | There are no rules for the exact logic of ordinary language, because that doesn't exist [Strawson,P] |
6413 | 'The present King of France is bald' presupposes existence, rather than stating it [Strawson,P, by Grayling] |
8354 | Russell asks when 'The King of France is wise' would be a true assertion [Strawson,P] |
10283 | A formula needs an 'interpretation' of its constants, and a 'valuation' of its variables [Hodges,W] |
10284 | There are three different standard presentations of semantics [Hodges,W] |
10285 | I |= φ means that the formula φ is true in the interpretation I [Hodges,W] |
10474 | |= should be read as 'is a model for' or 'satisfies' [Hodges,W] |
10473 | Model theory studies formal or natural language-interpretation using set-theory [Hodges,W] |
10475 | A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W] |
10481 | Models in model theory are structures, not sets of descriptions [Hodges,W] |
10288 | Down Löwenheim-Skolem: if a countable language has a consistent theory, that has a countable model [Hodges,W] |
10289 | Up Löwenheim-Skolem: if infinite models, then arbitrarily large models [Hodges,W] |
10287 | If a first-order theory entails a sentence, there is a finite subset of the theory which entails it [Hodges,W] |
10480 | First-order logic can't discriminate between one infinite cardinal and another [Hodges,W] |
10286 | A 'set' is a mathematically well-behaved class [Hodges,W] |
10303 | Restricted Platonism is just an ideal projection of a domain of thought [Bernays] |
10306 | Mathematical abstraction just goes in a different direction from logic [Bernays] |
16980 | We need a logical use of 'object' as predicate-worthy, and an 'ontological' use [Strawson,P] |
16979 | It makes no sense to ask of some individual thing what it is that makes it that individual [Strawson,P] |
9282 | I can only apply consciousness predicates to myself if I can apply them to others [Strawson,P] |
9263 | A person is an entity to which we can ascribe predicates of consciousness and corporeality [Strawson,P] |
8356 | The meaning of an expression or sentence is general directions for its use, to refer or to assert [Strawson,P] |
10430 | Reference is mainly a social phenomenon [Strawson,P, by Sainsbury] |
10448 | If an expression can refer to anything, it may still instrinsically refer, but relative to a context [Bach on Strawson,P] |
8355 | Expressions don't refer; people use expressions to refer [Strawson,P] |
8357 | If an utterance fails to refer then it is a pseudo-use, though a speaker may think they assert something [Strawson,P] |
9281 | The idea of a predicate matches a range of things to which it can be applied [Strawson,P] |