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How are the logical connectives not, and, or, and if-then used in formal logic?
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Logic
German philosopher of mathematics, logic, and language Gottlob Frege.
In formal logic, specifically within the propositional calculus, logical connectives are operators used to form new propositions from existing ones. These are known as truth-functional operators because the truth value of the resulting proposition is determined solely by the truth values of its arguments.1
The four primary connectives function as follows:
- Negation ("not," symbol ): A monadic operator that takes one argument. The proposition is true if is false, and false if is true.1
- Conjunction ("and," symbol ): A dyadic operator. The conjunction is true only when both and are true; otherwise, it is false.1
- Disjunction ("or," symbol ): A dyadic operator. The disjunction is false only when both and are false; it is true if at least one of the arguments is true.1
- Conditional ("if-then," symbol ): A dyadic operator representing material implication. The statement is false only when the antecedent () is true and the consequent () is false; in all other cases, it is true.1