39 ideas
| 7786 | Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle] |
| 7798 | There are three axiom schemas for propositional logic [Girle] |
| 7799 | Proposition logic has definitions for its three operators: or, and, and identical [Girle] |
| 7797 | Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle] |
| 7794 | There are seven modalities in S4, each with its negation [Girle] |
| 7793 | ◊p → □◊p is the hallmark of S5 [Girle] |
| 7795 | S5 has just six modalities, and all strings can be reduced to those [Girle] |
| 7787 | Possible worlds logics use true-in-a-world rather than true [Girle] |
| 7788 | Modal logic has four basic modal negation equivalences [Girle] |
| 7796 | Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle] |
| 7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
| 7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
| 7800 | Analytic truths are divided into logically and conceptually necessary [Girle] |
| 7801 | Possibilities can be logical, theoretical, physical, economic or human [Girle] |
| 7792 | A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle] |
| 23616 | Legal excuses are duress, ignorance, and diminished responsibility [McMahan] |
| 23606 | Liberty Rights are permissions, and Claim Rights are freedom from intervention [McMahan] |
| 23595 | The worst unjustified wars have no aim at all [McMahan] |
| 23619 | A defensive war is unjust, if it is responding to a just war [McMahan] |
| 23620 | A person or state may be attacked if they are responsible for an unjustified threat [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] |
| 23597 | Just war theory says all and only persons posing a threat are liable to attack [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] |
| 23599 | You don't become a legitimate target, just because you violently resist an unjust attack [McMahan] |
| 23596 | If all combatants are seen as morally equal, that facilitates starting unjust wars [McMahan] |
| 23604 | Volunteer soldiers accept the risk of attack, but they don't agree to it, or to their deaths [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] |
| 23605 | Soldiers cannot know enough facts to evaluate the justice of their war [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] |
| 19399 | Prime matter is nothing when it is at rest [Leibniz] |