13 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] |
| 14296 | Dispositions are physical states of mechanism; when known, these replace the old disposition term [Quine] |
| 14975 | A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell] |
| 13195 | To explain a house we must describe its use, as well as its parts [Leibniz] |
| 13193 | Active force is not just potential for action, since it involves a real effort or striving [Leibniz] |
| 13194 | God's laws would be meaningless without internal powers for following them [Leibniz] |
| 13196 | All qualities of bodies reduce to forces [Leibniz] |
| 13192 | Power is passive force, which is mass, and active force, which is entelechy or form [Leibniz] |