28 ideas
| 1564 | True and false statements can use exactly the same words [Anon (Diss)] |
| 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] |
| 16657 | Substance, Quantity and Quality are real; other categories depend on those three [Henry of Ghent] |
| 16658 | The only reality in the category of Relation is things from another category [Henry of Ghent] |
| 16645 | Accidents are diminished beings, because they are dispositions of substance (unqualified being) [Henry of Ghent] |
| 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] |
| 22012 | Kant says things-in-themselves cause sensations, but then makes causation transcendental! [Henry of Ghent, by Pinkard] |
| 1561 | Anything can be acceptable in some circumstances and unacceptable in others [Anon (Diss)] |
| 1560 | Lydians prostitute their daughters to raise a dowery, but no Greek would marry such a girl [Anon (Diss)] |
| 1559 | Thracians think tattooing adds to a girl's beauty, but elsewhere it is a punishment [Anon (Diss)] |
| 1567 | How could someone who knows everything fail to act correctly? [Anon (Diss)] |
| 1563 | Every apparent crime can be right in certain circumstances [Anon (Diss), by PG] |
| 1562 | It is right to lie to someone, to get them to take medicine they are reluctant to take [Anon (Diss)] |
| 1566 | The first priority in elections is to vote for people who support democracy [Anon (Diss)] |
| 1565 | We learn language, and we don't know who teaches us it [Anon (Diss)] |