74 ideas
354 | Wisdom makes virtue and true goodness possible [Plato] |
21405 | Cicero sees wisdom in terms of knowledge, but earlier Stoics saw it as moral [Cicero, by Long] |
20871 | Unfortunately we choose a way of life before we are old enough to think clearly [Cicero] |
15357 | Philosophy is the most general intellectual discipline [Horsten] |
370 | Philosophy is a purification of the soul ready for the afterlife [Plato] |
350 | In investigation the body leads us astray, but the soul gets a clear view of the facts [Plato] |
24226 | The soul on its own enters a pure, unchanging and eternal realm, and experiences wisdom [Plato] |
362 | The greatest misfortune for a person is to develop a dislike for argument [Plato] |
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] |
15340 | Tarski Bi-conditional: if you'll assert φ you'll assert φ-is-true - and also vice versa [Horsten] |
15354 | Tarski's hierarchy lacks uniform truth, and depends on contingent factors [Horsten] |
15345 | Semantic theories have a regress problem in describing truth in the languages for the models [Horsten] |
15332 | 'Reflexive' truth theories allow iterations (it is T that it is T that p) [Horsten] |
15346 | Axiomatic approaches to truth avoid the regress problem of semantic theories [Horsten] |
15361 | A good theory of truth must be compositional (as well as deriving biconditionals) [Horsten] |
15371 | An axiomatic theory needs to be of maximal strength, while being natural and sound [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] |
15373 | Axiomatic approaches avoid limiting definitions to avoid the truth predicate, and limited sizes of models [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] |
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] |
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] |
15368 | This deflationary account says truth has a role in generality, and in inference [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] |
13155 | If you add one to one, which one becomes two, or do they both become two? [Plato] |
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] |
15370 | Predicativism says mathematical definitions must not include the thing being defined [Horsten] |
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] |
21347 | If Simmias is taller than Socrates, that isn't a feature that is just in Simmias [Plato] |
360 | We must have a prior knowledge of equality, if we see 'equal' things and realise they fall short of it [Plato] |
24230 | The Forms arise whenever we talk of something 'in itself'. [Plato] |
24225 | Things like the Equal and the Beautiful, which are real, must be unchanging [Plato] |
24227 | One and one can only become two by sharing in Twoness [Plato] |
368 | Other things are named after the Forms because they participate in them [Plato] |
1 | There is only one source for all beauty [Plato] |
16516 | The ship which Theseus took to Crete is now sent to Delos crowned with flowers [Plato] |
15372 | Some claim that indicative conditionals are believed by people, even though they are not actually held true [Horsten] |
357 | People are obviously recollecting when they react to a geometrical diagram [Plato] |
359 | If we feel the inadequacy of a resemblance, we must recollect the original [Plato] |
9343 | To achieve pure knowledge, we must get rid of the body and contemplate things with the soul [Plato] |
15859 | To investigate the causes of things, study what is best for them [Plato] |
13154 | Do we think and experience with blood, air or fire, or could it be our brain? [Plato] |
364 | One soul can't be more or less of a soul than another [Plato] |
15347 | A theory of syntax can be based on Peano arithmetic, thanks to the translation by Gödel coding [Horsten] |
361 | It is a mistake to think that the most violent pleasure or pain is therefore the truest reality [Plato] |
351 | War aims at the acquisition of wealth, because we are enslaved to the body [Plato] |
6031 | The essence of propriety is consistency [Cicero] |
13156 | Fancy being unable to distinguish a cause from its necessary background conditions! [Plato] |
369 | If the Earth is spherical and in the centre, it is kept in place by universal symmetry, not by force [Plato] |
363 | Whether the soul pre-exists our body depends on whether it contains the ultimate standard of reality [Plato] |