23 ideas
15842 | An ad hominem refutation is reasonable, if it uses the opponent's assumptions [Harte,V] |
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] |
15841 | Mereology began as a nominalist revolt against the commitments of set theory [Harte,V] |
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] |
15858 | Traditionally, the four elements are just what persists through change [Harte,V] |
15848 | Mereology treats constitution as a criterion of identity, as shown in the axiom of extensionality [Harte,V] |
15837 | What exactly is a 'sum', and what exactly is 'composition'? [Harte,V] |
15839 | If something is 'more than' the sum of its parts, is the extra thing another part, or not? [Harte,V] |
15838 | The problem with the term 'sum' is that it is singular [Harte,V] |
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] |
1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |