139 ideas
| 22396 | We take courage, temperance, wisdom and justice as moral, but Aristotle takes wisdom as intellectual [Foot] |
| 22496 | Wisdom only implies the knowledge achievable in any normal lifetime [Foot] |
| 22397 | Wisdom is open to all, and not just to the clever or well trained [Foot] |
| 22462 | We should speak the truth, but also preserve and pursue it [Foot] |
| 9738 | Each line of a truth table is a model [Fitting/Mendelsohn] |
| 9727 | Modal logic adds □ (necessarily) and ◊ (possibly) to classical logic [Fitting/Mendelsohn] |
| 9726 | We let 'R' be the accessibility relation: xRy is read 'y is accessible from x' [Fitting/Mendelsohn] |
| 9737 | The symbol ||- is the 'forcing' relation; 'Γ ||- P' means that P is true in world Γ [Fitting/Mendelsohn] |
| 13136 | The prefix σ names a possible world, and σ.n names a world accessible from that one [Fitting/Mendelsohn] |
| 13727 | A 'constant' domain is the same for all worlds; 'varying' domains can be entirely separate [Fitting/Mendelsohn] |
| 9734 | Modern modal logic introduces 'accessibility', saying xRy means 'y is accessible from x' [Fitting/Mendelsohn] |
| 9736 | A 'model' is a frame plus specification of propositions true at worlds, written < G,R,||- > [Fitting/Mendelsohn] |
| 9735 | A 'frame' is a set G of possible worlds, with an accessibility relation R, written < G,R > [Fitting/Mendelsohn] |
| 9741 | Accessibility relations can be 'reflexive' (self-referring), 'transitive' (carries over), or 'symmetric' (mutual) [Fitting/Mendelsohn] |
| 13149 | S5: a) if n ◊X then kX b) if n ¬□X then k ¬X c) if n □X then k X d) if n ¬◊X then k ¬X [Fitting/Mendelsohn] |
| 13141 | Negation: if σ ¬¬X then σ X [Fitting/Mendelsohn] |
| 13138 | Disj: a) if σ ¬(X∨Y) then σ ¬X and σ ¬Y b) if σ X∨Y then σ X or σ Y [Fitting/Mendelsohn] |
| 13142 | Existential: a) if σ ◊X then σ.n X b) if σ ¬□X then σ.n ¬X [n is new] [Fitting/Mendelsohn] |
| 13144 | T reflexive: a) if σ □X then σ X b) if σ ¬◊X then σ ¬X [Fitting/Mendelsohn] |
| 13145 | D serial: a) if σ □X then σ ◊X b) if σ ¬◊X then σ ¬□X [Fitting/Mendelsohn] |
| 13146 | B symmetric: a) if σ.n □X then σ X b) if σ.n ¬◊X then σ ¬X [n occurs] [Fitting/Mendelsohn] |
| 13147 | 4 transitive: a) if σ □X then σ.n □X b) if σ ¬◊X then σ.n ¬◊X [n occurs] [Fitting/Mendelsohn] |
| 13148 | 4r rev-trans: a) if σ.n □X then σ □X b) if σ.n ¬◊X then σ ¬◊X [n occurs] [Fitting/Mendelsohn] |
| 9740 | If a proposition is possibly true in a world, it is true in some world accessible from that world [Fitting/Mendelsohn] |
| 9739 | If a proposition is necessarily true in a world, it is true in all worlds accessible from that world [Fitting/Mendelsohn] |
| 13137 | Conj: a) if σ X∧Y then σ X and σ Y b) if σ ¬(X∧Y) then σ ¬X or σ ¬Y [Fitting/Mendelsohn] |
| 13140 | Bicon: a)if σ(X↔Y) then σ(X→Y) and σ(Y→X) b) [not biconditional, one or other fails] [Fitting/Mendelsohn] |
| 13139 | Implic: a) if σ ¬(X→Y) then σ X and σ ¬Y b) if σ X→Y then σ ¬X or σ Y [Fitting/Mendelsohn] |
| 13143 | Universal: a) if σ ¬◊X then σ.m ¬X b) if σ □X then σ.m X [m exists] [Fitting/Mendelsohn] |
| 9742 | The system K has no accessibility conditions [Fitting/Mendelsohn] |
| 13114 | □P → P is not valid in D (Deontic Logic), since an obligatory action may be not performed [Fitting/Mendelsohn] |
| 9743 | The system D has the 'serial' conditon imposed on its accessibility relation [Fitting/Mendelsohn] |
| 9744 | The system T has the 'reflexive' conditon imposed on its accessibility relation [Fitting/Mendelsohn] |
| 9746 | The system K4 has the 'transitive' condition on its accessibility relation [Fitting/Mendelsohn] |
| 9745 | The system B has the 'reflexive' and 'symmetric' conditions on its accessibility relation [Fitting/Mendelsohn] |
| 9747 | The system S4 has the 'reflexive' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn] |
| 9748 | System S5 has the 'reflexive', 'symmetric' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn] |
| 9404 | Modality affects content, because P→◊P is valid, but ◊P→P isn't [Fitting/Mendelsohn] |
| 13112 | In epistemic logic knowers are logically omniscient, so they know that they know [Fitting/Mendelsohn] |
| 13111 | Read epistemic box as 'a knows/believes P' and diamond as 'for all a knows/believes, P' [Fitting/Mendelsohn] |
| 13113 | F: will sometime, P: was sometime, G: will always, H: was always [Fitting/Mendelsohn] |
| 13728 | The Barcan says nothing comes into existence; the Converse says nothing ceases; the pair imply stability [Fitting/Mendelsohn] |
| 13729 | The Barcan corresponds to anti-monotonicity, and the Converse to monotonicity [Fitting/Mendelsohn] |
| 9725 | 'Predicate abstraction' abstracts predicates from formulae, giving scope for constants and functions [Fitting/Mendelsohn] |
| 13730 | The Indiscernibility of Identicals has been a big problem for modal logic [Fitting/Mendelsohn] |
| 13725 | □ must be sensitive as to whether it picks out an object by essential or by contingent properties [Fitting/Mendelsohn] |
| 13731 | Objects retain their possible properties across worlds, so a bundle theory of them seems best [Fitting/Mendelsohn] |
| 13726 | Counterpart relations are neither symmetric nor transitive, so there is no logic of equality for them [Fitting/Mendelsohn] |
| 22449 | When we say 'is red' we don't mean 'seems red to most people' [Foot] |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| 22371 | Determinism threatens free will if actions can be causally traced to external factors [Foot] |
| 23438 | Full rationality must include morality [Foot] |
| 23437 | Practical reason is goodness in choosing actions [Foot] |
| 22480 | Possessing the virtue of justice disposes a person to good practical rationality [Foot] |
| 23694 | All criterions of practical rationality derive from goodness of will [Foot] |
| 22372 | Not all actions need motives, but it is irrational to perform troublesome actions with no motive [Foot] |
| 22393 | I don't understand the idea of a reason for acting, but it is probably the agent's interests or desires [Foot] |
| 23436 | It is an odd Humean view to think a reason to act must always involve caring [Foot] |
| 22481 | There is no restitution after a dilemma, if it only involved the agent, or just needed an explanation [Foot, by PG] |
| 22482 | I can't understand how someone can be necessarily wrong whatever he does [Foot] |
| 22384 | A 'double effect' is a foreseen but not desired side-effect, which may be forgivable [Foot] |
| 22465 | We see a moral distinction between doing and allowing to happen [Foot] |
| 22385 | The doctrine of double effect can excuse an outcome because it wasn't directly intended [Foot] |
| 22386 | Double effect says foreseeing you will kill someone is not the same as intending it [Foot] |
| 22387 | Without double effect, bad men can make us do evil by threatening something worse [Foot] |
| 22388 | Double effect seems to rely on a distinction between what we do and what we allow [Foot] |
| 22466 | We see a moral distinction between our aims and their foreseen consequences [Foot] |
| 22467 | Acts and omissions only matter if they concern doing something versus allowing it [Foot] |
| 4692 | It is not true that killing and allowing to die (or acts and omissions) are morally indistinguishable [Foot] |
| 4694 | Making a runaway tram kill one person instead of five is diverting a fatal sequence, not initiating one [Foot] |
| 22445 | Morality shows murder is wrong, but not what counts as a murder [Foot] |
| 22444 | A moral system must deal with the dangers and benefits of life [Foot] |
| 23683 | Moral norms are objective, connected to facts about human goods [Foot, by Hacker-Wright] |
| 22392 | Morality is inescapable, in descriptive words such as 'dishonest', 'unjust' and 'uncharitable' [Foot] |
| 22451 | All people need affection, cooperation, community and help in trouble [Foot] |
| 22485 | Non-cognitivists give the conditions of use of moral sentences as facts about the speaker [Foot] |
| 22474 | Unlike aesthetic evaluation, moral evaluation needs a concept of responsibility [Foot] |
| 23684 | Morality gives everyone reasons to act, irrespective of their desires [Foot, by Hacker-Wright] |
| 23690 | We all have reason to cultivate the virtues, even when we lack the desire [Foot, by Hacker-Wright] |
| 23685 | Reason is not a motivator of morality [Foot, by Hacker-Wright] |
| 23691 | Rejecting moral rules may be villainous, but it isn't inconsistent [Foot] |
| 23686 | Moral reason is not just neutral, because morality is part of the standard of rationality [Foot, by Hacker-Wright] |
| 23693 | Practical rationality must weigh both what is morally and what is non-morally required [Foot] |
| 23431 | Human defects are just like plant or animal defects [Foot] |
| 23687 | Moral virtues arise from human nature, as part of what makes us good human beings [Foot, by Hacker-Wright] |
| 22477 | Calling a knife or farmer or speech or root good does not involve attitudes or feelings [Foot] |
| 22486 | The mistake is to think good grounds aren't enough for moral judgement, which also needs feelings [Foot] |
| 23432 | Concepts such as function, welfare, flourishing and interests only apply to living things [Foot] |
| 22375 | Moral judgements need more than the relevant facts, if the same facts lead to 'x is good' and 'x is bad' [Foot] |
| 22493 | Sterility is a human defect, but the choice to be childless is not [Foot] |
| 22492 | Virtues are as necessary to humans as stings are to bees [Foot] |
| 23433 | Humans need courage like a plant needs roots [Foot] |
| 22378 | We can't affirm a duty without saying why it matters if it is not performed [Foot] |
| 22487 | Moral arguments are grounded in human facts [Foot] |
| 22377 | Whether someone is rude is judged by agreed criteria, so the facts dictate the value [Foot] |
| 22376 | Facts and values are connected if we cannot choose what counts as evidence of rightness [Foot] |
| 22491 | Moral evaluations are not separate from facts, but concern particular facts about functioning [Foot] |
| 23434 | There is no fact-value gap in 'owls should see in the dark' [Foot] |
| 22447 | Saying something 'just is' right or wrong creates an illusion of fact and objectivity [Foot] |
| 22452 | Do we have a concept of value, other than wanting something, or making an effort to get it? [Foot] |
| 23439 | Principles are not ultimate, but arise from the necessities of human life [Foot] |
| 23435 | If you demonstrate the reason to act, there is no further question of 'why should I?' [Foot] |
| 22381 | Being a good father seems to depend on intentions, rather than actual abilities [Foot] |
| 22379 | The meaning of 'good' and other evaluations must include the object to which they attach [Foot] |
| 22458 | Consequentialists can hurt the innocent in order to prevent further wickedness [Foot] |
| 22460 | Why might we think that a state of affairs can be morally good or bad? [Foot] |
| 22461 | Good outcomes are not external guides to morality, but a part of virtuous actions [Foot] |
| 22464 | The idea of a good state of affairs has no role in the thought of Aristotle, Rawls or Scanlon [Foot] |
| 22497 | Deep happiness usually comes from the basic things in life [Foot] |
| 22498 | Happiness is enjoying the pursuit and attainment of right ends [Foot] |
| 23695 | Good actions can never be justified by the good they brings to their agent [Foot] |
| 22470 | A good moral system benefits its participants, and so demands reciprocity [Foot] |
| 22499 | We all know that just pretending to be someone's friend is not the good life [Foot] |
| 22402 | Most people think virtues can be displayed in bad actions [Foot] |
| 23145 | Virtues are intended to correct design flaws in human beings [Foot, by Driver] |
| 22401 | Actions can be in accordance with virtue, but without actually being virtuous [Foot] |
| 22398 | Virtues are corrective, to resist temptation or strengthen motivation [Foot] |
| 22478 | The essential thing is the 'needs' of plants and animals, and their operative parts [Foot] |
| 23692 | Good and bad are a matter of actions, not of internal dispositions [Foot] |
| 22468 | Virtues can have aims, but good states of affairs are not among them [Foot] |
| 22495 | Someone is a good person because of their rational will, not their body or memory [Foot] |
| 22373 | People can act out of vanity without being vain, or even vain about this kind of thing [Foot] |
| 22456 | Maybe virtues conflict with each other, if some virtue needs a vice for its achievement [Foot] |
| 22469 | Some virtues imply rules, and others concern attachment [Foot] |
| 22403 | Temperance is not a virtue if it results from timidity or excessive puritanism [Foot] |
| 22472 | The practice of justice may well need a recognition of human equality [Foot] |
| 22479 | Observing justice is necessary to humans, like hunting to wolves or dancing to bees [Foot] |
| 22400 | Courage overcomes the fears which should be overcome, and doesn't overvalue personal safety [Foot] |
| 22391 | Saying we 'ought to be moral' makes no sense, unless it relates to some other system [Foot] |
| 22389 | Morality no more consists of categorical imperatives than etiquette does [Foot] |
| 22395 | Moral judgements are hypothetical, because they depend on interests and desires [Foot] |
| 22448 | We sometimes just use the word 'should' to impose a rule of conduct on someone [Foot] |
| 22463 | Morality is seen as tacit legislation by the community [Foot] |
| 22459 | For consequentialism, it is irrational to follow a rule which in this instance ends badly [Foot] |
| 22502 | Refraining from murder is not made good by authenticity or self-fulfilment [Foot] |
| 4693 | The right of non-interference (with a 'negative duty'), and the right to goods/services ('positive') [Foot] |
| 22383 | Abortion is puzzling because we do and don't want the unborn child to have rights [Foot] |
| 22446 | In the case of something lacking independence, calling it a human being is a matter of choice [Foot] |
| 22380 | Some words, such as 'knife', have a meaning which involves its function [Foot] |