11 ideas
14970 | Normal system K has five axioms and rules [Cresswell] |
14971 | D is valid on every serial frame, but not where there are dead ends [Cresswell] |
14972 | S4 has 14 modalities, and always reduces to a maximum of three modal operators [Cresswell] |
14973 | In S5 all the long complex modalities reduce to just three, and their negations [Cresswell] |
14976 | Reject the Barcan if quantifiers are confined to worlds, and different things exist in other worlds [Cresswell] |
21548 | The null class is the class with all the non-existents as its members [MacColl, by Lackey] |
14974 | A relation is 'Euclidean' if aRb and aRc imply bRc [Cresswell] |
14975 | A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell] |
21796 | Man is God if he raises himself, by denying his nature and finitude [Hegel] |
21783 | State slavery is a phase of education, moving towards a full culture [Hegel] |
21784 | Slavery is unjust, because humanity is essentially free [Hegel] |