40 ideas
| 18951 | For scientific purposes there is a precise concept of 'true-in-L', using set theory [Putnam] |
| 18953 | Modern notation frees us from Aristotle's restriction of only using two class-names in premises [Putnam] |
| 18949 | The universal syllogism is now expressed as the transitivity of subclasses [Putnam] |
| 18952 | '⊃' ('if...then') is used with the definition 'Px ⊃ Qx' is short for '¬(Px & ¬Qx)' [Putnam] |
| 18958 | In type theory, 'x ∈ y' is well defined only if x and y are of the appropriate type [Putnam] |
| 18954 | Before the late 19th century logic was trivialised by not dealing with relations [Putnam] |
| 18956 | Asserting first-order validity implicitly involves second-order reference to classes [Putnam] |
| 18962 | Unfashionably, I think logic has an empirical foundation [Putnam] |
| 18961 | We can identify functions with certain sets - or identify sets with certain functions [Putnam] |
| 18955 | Having a valid form doesn't ensure truth, as it may be meaningless [Putnam] |
| 18959 | Sets larger than the continuum should be studied in an 'if-then' spirit [Putnam] |
| 18933 | Not-Being obviously doesn't exist, and the five modes of Being are all impossible [Gorgias, by Diog. Laertius] |
| 18957 | Nominalism only makes sense if it is materialist [Putnam] |
| 18950 | Physics is full of non-physical entities, such as space-vectors [Putnam] |
| 18960 | Most predictions are uninteresting, and are only sought in order to confirm a theory [Putnam] |
| 5864 | Destroy seriousness with laughter, and laughter with seriousness [Gorgias] |
| 9866 | Gorgias says rhetoric is the best of arts, because it enslaves without using force [Gorgias, by Plato] |
| 23616 | Legal excuses are duress, ignorance, and diminished responsibility [McMahan] |
| 23606 | Liberty Rights are permissions, and Claim Rights are freedom from intervention [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] |
| 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] |
| 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] |