28 ideas
| 12036 | Xenophanes began the concern with knowledge [Annas] |
| 12046 | Plato was the first philosopher who was concerned to systematize his ideas [Annas] |
| 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] |
| 12887 | A whole must have one characteristic, an internal relation, and a structure [Rescher/Oppenheim] |
| 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] |
| 3546 | 'Phronesis' should translate as 'practical intelligence', not as prudence [Annas] |
| 12037 | Euripides's Medea is a key case of reason versus the passions [Annas] |
| 3547 | Epicureans achieve pleasure through character development [Annas] |
| 3543 | Cyrenaics pursue pleasure, but don't equate it with happiness [Annas] |
| 12040 | Virtue is a kind of understanding of moral value [Annas] |
| 3541 | Ancient ethics uses attractive notions, not imperatives [Annas] |
| 3550 | Principles cover life as a whole, where rules just cover actions [Annas] |
| 3551 | Virtue theory tries to explain our duties in terms of our character [Annas] |
| 3552 | If excessively good actions are admirable but not required, then duty isn't basic [Annas] |
| 3542 | We should do good when necessary, not maximise it [Annas] |