99 ideas
7914 | To try to be wise all on one's own is folly [Rochefoucauld] |
15357 | Philosophy is the most general intellectual discipline [Horsten] |
15352 | A definition should allow the defined term to be eliminated [Horsten] |
10882 | Predicative definitions only refer to entities outside the defined collection [Horsten] |
15323 | Truth is a property, because the truth predicate has an extension [Horsten] |
15324 | Semantic theories of truth seek models; axiomatic (syntactic) theories seek logical principles [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] |
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] |
15356 | Deflationism concerns the nature and role of truth, but not its laws [Horsten] |
15344 | Deflationism skips definitions and models, and offers just accounts of basic laws of truth [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] |
10884 | A theory is 'categorical' if it has just one model up to isomorphism [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] |
10885 | Computer proofs don't provide explanations [Horsten] |
10881 | The concept of 'ordinal number' is set-theoretic, not arithmetical [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] |
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] |
15372 | Some claim that indicative conditionals are believed by people, even though they are not actually held true [Horsten] |
7118 | La Rochefoucauld's idea of disguised self-love implies an unconscious mind [Rochefoucauld, by Sartre] |
4669 | Persons are conscious, they relate, they think, they feel, and they are self-aware [Glover] |
15347 | A theory of syntax can be based on Peano arithmetic, thanks to the translation by Gödel coding [Horsten] |
4656 | A problem arises in any moral system that allows more than one absolute right [Glover] |
4657 | Double Effect: no bad acts with good consequences, but possibly good acts despite bad consequences [Glover] |
4658 | Acts and Omissions: bad consequences are morally better if they result from an omission rather than an act [Glover] |
4659 | It doesn't seem worse to switch off a life-support machine than to forget to switch it on [Glover] |
4660 | Harmful omissions are unavoidable, while most harmful acts can be avoided [Glover] |
4661 | What matters is not intrinsic value of life or rights, but worthwhile and desired life, and avoidance of pain [Glover] |
4648 | 'Death' is best seen as irreversible loss of consciousness, since this is why we care about brain function [Glover] |
7912 | Judging by effects, love looks more like hatred than friendship [Rochefoucauld] |
7915 | Supreme cleverness is knowledge of the real value of things [Rochefoucauld] |
3785 | You can't separate acts from the people performing them [Glover] |
3786 | Aggression in defence may be beneficial but morally corrupting [Glover] |
7917 | Realising our future misery is a kind of happiness [Rochefoucauld] |
4650 | The quality of a life is not altogether independent of its length [Glover] |
7913 | Virtue doesn't go far without the support of vanity [Rochefoucauld] |
7916 | True friendship is even rarer than true love [Rochefoucauld] |
3784 | Duty prohibits some acts, whatever their consequences [Glover] |
3782 | Satisfaction of desires is not at all the same as achieving happiness [Glover, by PG] |
3787 | Rule-utilitarianism is either act-utilitarianism, or not really utilitarian [Glover] |
9299 | We are bored by people to whom we ourselves are boring [Rochefoucauld] |
3783 | How can utilitarianism decide the ideal population size? [Glover] |
4675 | The sanctity of life doctrine implies a serious increase of abnormality among the population [Glover] |
4654 | Autonomy favours present opinions over future ones, and says nothing about the interests of potential people [Glover] |
4655 | If a whole community did not mind death, respect for autonomy suggests that you could kill them all [Glover] |
4680 | Autonomy seems to acquire greater weight when the decision is more important to a person [Glover] |
4670 | Being alive is not intrinsically good, and there is no 'right to life' [Glover] |
4668 | You can't have a right to something you can't desire, so a foetus has no 'right' to life [Glover] |
4649 | If someone's life is 'worth living', that gives one direct reason not to kill him [Glover] |
4651 | Utilitarians object to killing directly (pain, and lost happiness), and to side-effects (loss to others, and precedents) [Glover] |
4671 | What is wrong with killing someone, if another equally worthwhile life is substituted? [Glover] |
4676 | The 'no trade-off' position: killing is only justified if it prevents other deaths [Glover] |
4685 | Societies spend a lot to save known persons, but very little to reduce fatal accidents [Glover] |
4681 | The Nazi mass murders seem to have originated in their euthanasia programme [Glover] |
4682 | Euthanasia is voluntary (patient's wish), or involuntary (ignore wish), or non-voluntary (no wish possible) [Glover] |
4683 | Involuntary euthanasia is wrong because it violates autonomy, and it has appalling side-effects [Glover] |
4684 | Maybe extreme treatment is not saving life, but prolonging the act of dying [Glover] |
4673 | Abortion differs morally from deliberate non-conception only in its side-effects [Glover] |
4652 | If killing is wrong because it destroys future happiness, not conceiving a happy child is also wrong [Glover] |
4665 | Conception isn't the fixed boundary for a person's beginning, because twins are possible within two weeks [Glover] |
4662 | Defenders of abortion focus on early pregnancy, while opponents focus on later stages [Glover] |
4663 | If abortion is wrong, it is because a foetus is a human being or a person (or potentially so) [Glover] |
4664 | If abortion is wrong because of the 'potential' person, that makes contraception wrong too [Glover] |
4666 | If viability is a test or boundary at the beginning of life, it should also be so for frail old people [Glover] |
4672 | Apart from side effects, it seems best to replace an inadequate foetus with one which has a better chance [Glover] |
4674 | It is always right for a qualified person to perform an abortion when requested by the mother [Glover] |
4667 | How would we judge abortion if mothers had transparent wombs? [Glover] |
4679 | One test for a worthwhile life is to assess the amount of life for which you would rather be unconscious [Glover] |