29 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] |
11211 | If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt] |
7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
11212 | The sense of a connective comes from primitively obvious rules of inference [Rumfitt] |
11210 | Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt] |
12797 | If plural variables have 'some values', then non-count variables have 'some value' [Laycock] |
12794 | Plurals are semantical but not ontological [Laycock] |
7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
17694 | Some non-count nouns can be used for counting, as in 'several wines' or 'fewer cheeses' [Laycock] |
17695 | Some apparent non-count words can take plural forms, such as 'snows' or 'waters' [Laycock] |
12792 | The category of stuff does not suit reference [Laycock] |
12799 | Descriptions of stuff are neither singular aggregates nor plural collections [Laycock] |
12818 | We shouldn't think some water retains its identity when it is mixed with air [Laycock] |
12795 | Parts must be of the same very general type as the wholes [Laycock] |
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] |
17696 | 'Humility is a virtue' has an abstract noun, but 'water is a liquid' has a generic concrete noun [Laycock] |
12791 | It is said that proper reference is our intellectual link with the world [Laycock] |
11214 | We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt] |