Combining Texts

All the ideas for '', 'Substitutional Classes and Relations' and 'Modal Logics and Philosophy'

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23 ideas

2. Reason / D. Definition / 7. Contextual Definition
21560 Any linguistic expression may lack meaning when taken out of context [Russell]
2. Reason / F. Fallacies / 8. Category Mistake / a. Category mistakes
21561 'The number one is bald' or 'the number one is fond of cream cheese' are meaningless [Russell]
4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic
7786 Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle]
7798 There are three axiom schemas for propositional logic [Girle]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / a. Symbols of PL
7799 Proposition logic has definitions for its three operators: or, and, and identical [Girle]
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
7797 Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4
7794 There are seven modalities in S4, each with its negation [Girle]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
7793 ◊p → □◊p is the hallmark of S5 [Girle]
7795 S5 has just six modalities, and all strings can be reduced to those [Girle]
4. Formal Logic / D. Modal Logic ML / 4. Alethic Modal Logic
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]
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
18130 Axiom of Reducibility: there is always a function of the lowest possible order in a given level [Russell, by Bostock]
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
11211 If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt]
5. Theory of Logic / B. Logical Consequence / 7. Strict Implication
7789 Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle]
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
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]
5. Theory of Logic / H. Proof Systems / 5. Tableau Proof
7790 If an argument is invalid, a truth tree will indicate a counter-example [Girle]
8. Modes of Existence / A. Relations / 1. Nature of Relations
21562 There is no complexity without relations, so no propositions, and no truth [Russell]
10. Modality / A. Necessity / 3. Types of Necessity
7800 Analytic truths are divided into logically and conceptually necessary [Girle]
10. Modality / B. Possibility / 1. Possibility
7801 Possibilities can be logical, theoretical, physical, economic or human [Girle]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
7792 A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle]
19. Language / F. Communication / 3. Denial
11214 We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt]