88 ideas
5196 | Philosophy is a department of logic [Ayer] |
15357 | Philosophy is the most general intellectual discipline [Horsten] |
5189 | Philosophers should abandon speculation, as philosophy is wholly critical [Ayer] |
7919 | Humeans rejected the a priori synthetic, and so rejected even Kantian metaphysics [Ayer, by Macdonald,C] |
5195 | Critics say analysis can only show the parts, and not their distinctive configuration [Ayer] |
5179 | Philosophy deals with the questions that scientists do not wish to handle [Ayer] |
15352 | A definition should allow the defined term to be eliminated [Horsten] |
15324 | Semantic theories of truth seek models; axiomatic (syntactic) theories seek logical principles [Horsten] |
15323 | Truth is a property, because the truth predicate has an extension [Horsten] |
15374 | Truth has no 'nature', but we should try to describe its behaviour in inferences [Horsten] |
15348 | Propositions have sentence-like structures, so it matters little which bears the truth [Horsten] |
15333 | Modern correspondence is said to be with the facts, not with true propositions [Horsten] |
15337 | The correspondence 'theory' is too vague - about both 'correspondence' and 'facts' [Horsten] |
15334 | The coherence theory allows multiple coherent wholes, which could contradict one another [Horsten] |
15336 | The pragmatic theory of truth is relative; useful for group A can be useless for group B [Horsten] |
15354 | Tarski's hierarchy lacks uniform truth, and depends on contingent factors [Horsten] |
15340 | Tarski Bi-conditional: if you'll assert φ you'll assert φ-is-true - and also vice versa [Horsten] |
15345 | Semantic theories have a regress problem in describing truth in the languages for the models [Horsten] |
15373 | Axiomatic approaches avoid limiting definitions to avoid the truth predicate, and limited sizes of models [Horsten] |
15346 | Axiomatic approaches to truth avoid the regress problem of semantic theories [Horsten] |
15371 | An axiomatic theory needs to be of maximal strength, while being natural and sound [Horsten] |
15332 | 'Reflexive' truth theories allow iterations (it is T that it is T that p) [Horsten] |
15361 | A good theory of truth must be compositional (as well as deriving biconditionals) [Horsten] |
15350 | The Naďve Theory takes the bi-conditionals as axioms, but it is inconsistent, and allows the Liar [Horsten] |
15351 | Axiomatic theories take truth as primitive, and propose some laws of truth as axioms [Horsten] |
15367 | By adding truth to Peano Arithmetic we increase its power, so truth has mathematical content! [Horsten] |
15330 | Friedman-Sheard theory keeps classical logic and aims for maximum strength [Horsten] |
15331 | Kripke-Feferman has truth gaps, instead of classical logic, and aims for maximum strength [Horsten] |
4749 | We cannot analyse the concept of 'truth', because it is simply a mark that a sentence is asserted [Ayer] |
15325 | Inferential deflationism says truth has no essence because no unrestricted logic governs the concept [Horsten] |
15344 | Deflationism skips definitions and models, and offers just accounts of basic laws of truth [Horsten] |
15356 | Deflationism concerns the nature and role of truth, but not its laws [Horsten] |
15368 | This deflationary account says truth has a role in generality, and in inference [Horsten] |
15358 | Deflationism says truth isn't a topic on its own - it just concerns what is true [Horsten] |
15359 | Deflation: instead of asserting a sentence, we can treat it as an object with the truth-property [Horsten] |
15329 | Nonclassical may accept T/F but deny applicability, or it may deny just T or F as well [Horsten] |
15326 | Doubt is thrown on classical logic by the way it so easily produces the liar paradox [Horsten] |
15341 | Deduction Theorem: ψ only derivable from φ iff φ→ψ are axioms [Horsten] |
15328 | A theory is 'non-conservative' if it facilitates new mathematical proofs [Horsten] |
15349 | It is easier to imagine truth-value gaps (for the Liar, say) than for truth-value gluts (both T and F) [Horsten] |
15366 | Satisfaction is a primitive notion, and very liable to semantical paradoxes [Horsten] |
15353 | The first incompleteness theorem means that consistency does not entail soundness [Horsten] |
15355 | Strengthened Liar: 'this sentence is not true in any context' - in no context can this be evaluated [Horsten] |
15364 | English expressions are denumerably infinite, but reals are nondenumerable, so many are unnameable [Horsten] |
15360 | ZFC showed that the concept of set is mathematical, not logical, because of its existence claims [Horsten] |
15369 | Set theory is substantial over first-order arithmetic, because it enables new proofs [Horsten] |
5202 | Maths and logic are true universally because they are analytic or tautological [Ayer] |
15370 | Predicativism says mathematical definitions must not include the thing being defined [Horsten] |
6523 | Positivists regard ontology as either meaningless or stipulated [Ayer, by Robinson,H] |
15338 | We may believe in atomic facts, but surely not complex disjunctive ones? [Horsten] |
15363 | In the supervaluationist account, disjunctions are not determined by their disjuncts [Horsten] |
15362 | If 'Italy is large' lacks truth, so must 'Italy is not large'; but classical logic says it's large or it isn't [Horsten] |
15372 | Some claim that indicative conditionals are believed by people, even though they are not actually held true [Horsten] |
5183 | Only tautologies can be certain; other propositions can only be probable [Ayer] |
6525 | Logical positivists could never give the sense-data equivalent of 'there is a table next door' [Robinson,H on Ayer] |
5170 | Material things are constructions from actual and possible occurrences of sense-contents [Ayer] |
5198 | We could verify 'a thing can't be in two places at once' by destroying one of the things [Ierubino on Ayer] |
2619 | Whether geometry can be applied to reality is an empirical question outside of geometry [Ayer] |
5197 | By changing definitions we could make 'a thing can't be in two places at once' a contradiction [Ayer] |
5204 | To say that a proposition is true a priori is to say that it is a tautology [Ayer] |
6524 | Positivists prefer sense-data to objects, because the vocabulary covers both illusions and perceptions [Ayer, by Robinson,H] |
5193 | Causal and representative theories of perception are wrong as they refer to unobservables [Ayer] |
5200 | The main claim of rationalism is that thought is an independent source of knowledge [Ayer] |
4729 | Empiricism lacked a decent account of the a priori, until Ayer said it was entirely analytic [O'Grady on Ayer] |
5180 | All propositions (especially 'metaphysics') must begin with the senses [Ayer] |
5169 | My empiricism logically distinguishes analytic and synthetic propositions, and metaphysical verbiage [Ayer] |
5185 | It is further sense-experience which informs us of the mistakes that arise out of sense-experience [Ayer] |
5199 | Empiricism, it is said, cannot account for our knowledge of necessary truths [Ayer] |
5190 | The induction problem is to prove generalisations about the future based on the past [Ayer] |
5191 | We can't use the uniformity of nature to prove induction, as that would be circular [Ayer] |
5177 | Other minds are 'metaphysical' objects, because I can never observe their experiences [Ayer] |
5178 | A conscious object is by definition one that behaves in a certain way, so behaviour proves consciousness [Ayer] |
5172 | If the self is meaningful, it must be constructed from sense-experiences [Ayer] |
5173 | Two experiences belong to one self if their contents belong with one body [Ayer] |
5176 | Empiricists can define personal identity as bodily identity, which consists of sense-contents [Ayer] |
5171 | The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances' [Ayer] |
5181 | A sentence is factually significant to someone if they know how to verify its proposition [Ayer] |
5184 | Factual propositions imply (in conjunction with a few other premises) possible experiences [Ayer] |
5186 | Tautologies and empirical hypotheses form the entire class of significant propositions [Ayer] |
15347 | A theory of syntax can be based on Peano arithmetic, thanks to the translation by Gödel coding [Horsten] |
468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
5205 | Moral intuition is worthless if there is no criterion to decide between intuitions [Ayer] |
23725 | Ayer defends the emotivist version of expressivism [Ayer, by Smith,M] |
5206 | To say an act is wrong makes no further statement about it, but merely expresses disapproval [Ayer] |
5208 | A person with non-empirical attributes is unintelligible. [Ayer] |
5187 | When we ascribe an attribute to a thing, we covertly assert that it exists [Ayer] |
5207 | If theism is non-sensical, then so is atheism. [Ayer] |
5209 | The 'truths' expressed by theists are not literally significant [Ayer] |