23 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] |
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] |
18383 | Plantinga says there is just this world, with possibilities expressed in propositions [Plantinga, by Armstrong] |
11891 | Possibilities for an individual can only refer to that individual, in some possible world [Plantinga, by Mackie,P] |
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] |
20704 | A possible world contains a being of maximal greatness - which is existence in all worlds [Plantinga, by Davies,B] |