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4. Formal Logic / B. Propositional Logic PL / 1. Propositional Logic

[overview of the logical relationships between propositions]

12 ideas
Stoic propositional logic is like chemistry - how atoms make molecules, not the innards of atoms [Devlin on Chrysippus]
Boole applied normal algebra to logic, aiming at an algebra of thought [Devlin on Boole]
Boole's notation can represent syllogisms and propositional arguments, but not both at once [Weiner on Boole]
'Contradictory' propositions always differ in truth-value [Lemmon]
Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin]
Aristotelian logic dealt with inferences about concepts, and there were also proposition inferences [Weiner]
Sentential logic is consistent (no contradictions) and complete (entirely provable) [Orenstein]
Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle]
There are three axiom schemas for propositional logic [Girle]
Post proved the consistency of propositional logic in 1921 [Walicki]
Propositional language can only relate statements as the same or as different [Walicki]
Semantics for propositions: 1) validity preserves truth 2) non-contradition 3) bivalence 4) truth tables [Rumfitt]