55 ideas
| 7791 | The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle] |
| 9358 | There are several logics, none of which will ever derive falsehoods from truth [Lewis,CI] |
| 9357 | Excluded middle is just our preference for a simplified dichotomy in experience [Lewis,CI] |
| 9364 | Names represent a uniformity in experience, or they name nothing [Lewis,CI] |
| 1553 | No perceptible object is truly straight or curved [Protagoras] |
| 11002 | Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read] |
| 9362 | Necessary truths are those we will maintain no matter what [Lewis,CI] |
| 7803 | Modal logic began with translation difficulties for 'If...then' [Lewis,CI, by Girle] |
| 1549 | Everything that exists consists in being perceived [Protagoras] |
| 9365 | We can maintain a priori principles come what may, but we can also change them [Lewis,CI] |
| 21500 | We rely on memory for empirical beliefs because they mutually support one another [Lewis,CI] |
| 21501 | If we doubt memories we cannot assess our doubt, or what is being doubted [Lewis,CI] |
| 6556 | If anything is to be probable, then something must be certain [Lewis,CI] |
| 21498 | Congruents assertions increase the probability of each individual assertion in the set [Lewis,CI] |
| 1545 | Protagoras was the first to claim that there are two contradictory arguments about everything [Protagoras, by Diog. Laertius] |
| 1547 | Man is the measure of all things - of things that are, and of things that are not [Protagoras] |
| 3305 | There is no more purely metaphysical doctrine than Protagorean relativism [Benardete,JA on Protagoras] |
| 3313 | If my hot wind is your cold wind, then wind is neither hot nor cold, and so not as cold as itself [Benardete,JA on Protagoras] |
| 3317 | You can only state the problem of the relative warmth of an object by agreeing on the underlying object [Benardete,JA on Protagoras] |
| 247 | God is "the measure of all things", more than any man [Plato on Protagoras] |
| 606 | Protagoras absurdly thought that the knowing or perceiving man is 'the measure of all things' [Aristotle on Protagoras] |
| 612 | Relativists think if you poke your eye and see double, there must be two things [Aristotle on Protagoras] |
| 5828 | Extension is the class of things, intension is the correct definition of the thing, and intension determines extension [Lewis,CI] |
| 9361 | We have to separate the mathematical from physical phenomena by abstraction [Lewis,CI] |
| 23616 | Legal excuses are duress, ignorance, and diminished responsibility [McMahan] |
| 6016 | Early sophists thought convention improved nature; later they said nature was diminished by it [Protagoras, by Miller,FD] |
| 1580 | For Protagoras the only bad behaviour is that which interferes with social harmony [Protagoras, by Roochnik] |
| 205 | Protagoras contradicts himself by saying virtue is teachable, but then that it is not knowledge [Plato on Protagoras] |
| 23606 | Liberty Rights are permissions, and Claim Rights are freedom from intervention [McMahan] |
| 1659 | Protagoras seems to have made the huge move of separating punishment from revenge [Protagoras, by Vlastos] |
| 23595 | The worst unjustified wars have no aim at all [McMahan] |
| 23597 | Just war theory says all and only persons posing a threat are liable to attack [McMahan] |
| 23598 | You (e.g. a police officer) are not liable to attack just because you pose a threat [McMahan] |
| 23594 | Wars can be unjust, despite a just cause, if they are unnecessary or excessive or of mixed cause [McMahan] |
| 23620 | A person or state may be attacked if they are responsible for an unjustified threat [McMahan] |
| 23619 | A defensive war is unjust, if it is responding to a just war [McMahan] |
| 23600 | Proportionality in fighting can't be judged independently of the justice of each side [McMahan] |
| 23603 | Can an army start an unjust war, and then fight justly to defend their own civilians? [McMahan] |
| 23611 | Soldiers cannot freely fight in unjust wars, just because they behave well when fighting [McMahan] |
| 23612 | The law of war differs from criminal law; attacking just combatants is immoral, but legal [McMahan] |
| 23617 | If the unjust combatants are morally excused they are innocent, so how can they be killed? [McMahan] |
| 23596 | If all combatants are seen as morally equal, that facilitates starting unjust wars [McMahan] |
| 23599 | You don't become a legitimate target, just because you violently resist an unjust attack [McMahan] |
| 23604 | Volunteer soldiers accept the risk of attack, but they don't agree to it, or to their deaths [McMahan] |
| 23605 | Soldiers cannot know enough facts to evaluate the justice of their war [McMahan] |
| 23608 | If being part of a big collective relieves soldiers of moral responsibility, why not the leaders too? [McMahan] |
| 23610 | If soldiers can't refuse to fight in unjust wars, can they choose to fight in just wars? [McMahan] |
| 23613 | Equality is both sides have permission, or both sides are justified, or one justified the other permitted [McMahan] |
| 23615 | Fighting unjustly under duress does not justify it, or permit it, but it may excuse it [McMahan] |
| 23602 | Innocence implies not being morally responsible, rather than merely being guiltless [McMahan] |
| 23618 | Unconditional surrender can't be demanded, since evil losers still have legitimate conditions [McMahan] |
| 532 | Successful education must go deep into the soul [Protagoras] |
| 1552 | He spent public money on education, as it benefits the individual and the state [Protagoras, by Diodorus of Sicily] |
| 9363 | Science seeks classification which will discover laws, essences, and predictions [Lewis,CI] |
| 1551 | He said he didn't know whether there are gods - but this is the same as atheism [Diogenes of Oen. on Protagoras] |