12 ideas
| 17750 | The first clear proof of the consistency of the first order predicate logic was in 1928 [Hilbert/Ackermann, by Walicki] |
| 9456 | Modal logic is multiple systems, shown in the variety of accessibility relations between worlds [Jacquette] |
| 9457 | The two main views in philosophy of logic are extensionalism and intensionalism [Jacquette] |
| 9458 | Extensionalists say that quantifiers presuppose the existence of their objects [Jacquette] |
| 9461 | Intensionalists say meaning is determined by the possession of properties [Jacquette] |
| 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] |
| 9460 | Extensionalist semantics forbids reference to nonexistent objects [Jacquette] |
| 9459 | Extensionalist semantics is circular, as we must know the extension before assessing 'Fa' [Jacquette] |
| 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] |