30 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] |
| 3523 | Shadows are supervenient on their objects, but not reducible [Maslin] |
| 3517 | 'Ontology' means 'study of things which exist' [Maslin] |
| 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] |
| 3538 | Analogy to other minds is uncheckable, over-confident and chauvinistic [Maslin] |
| 3540 | If we are brains then we never meet each other [Maslin] |
| 3518 | I'm not the final authority on my understanding of maths [Maslin] |
| 3530 | Denial of purely mental causation will lead to epiphenomenalism [Maslin] |
| 3520 | Token-identity removes the explanatory role of the physical [Maslin] |
| 9261 | The 'Ethics' is disappointing, because it fails to try to justify our duties [Prichard] |
| 9262 | The mistake is to think we can prove what can only be seen directly in moral thinking [Prichard] |
| 9260 | Virtues won't generate an obligation, so it isn't a basis for morality [Prichard] |
| 9259 | We feel obligations to overcome our own failings, and these are not relations to other people [Prichard] |
| 9258 | If pain were instrinsically wrong, it would be immoral to inflict it on ourselves [Prichard] |
| 3528 | Causality may require that a law is being followed [Maslin] |
| 3525 | Strict laws make causation logically necessary [Maslin] |
| 3527 | Strict laws allow no exceptions and are part of a closed system [Maslin] |