12 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] |
| 14974 | A relation is 'Euclidean' if aRb and aRc imply bRc [Cresswell] |
| 10414 | Abstract objects are constituted by encoded collections of properties [Zalta, by Swoyer] |
| 10558 | Abstract objects are actually constituted by the properties by which we conceive them [Zalta] |
| 10415 | Properties make round squares and round triangles distinct, unlike exemplification [Zalta, by Swoyer] |
| 14975 | A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell] |
| 10557 | Abstract objects are captured by second-order modal logic, plus 'encoding' formulas [Zalta] |
| 1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |