Concept · Foundations
Validity
The property of an argument whose conclusion cannot be false while all its premises are true.
Why it matters
Validity is the central standard of deductive evaluation, and in propositional logic it can be mechanically tested.
Lessons (9)
Building Short Formal ProofsPropositional Logic: Form, Connectives, and Valid InferenceCapstone: Building and Defending a Complete Deductive ArgumentNatural Deduction: Validity and Formal ProofCapstone: Diagnosing Real-World ReasoningFoundations of Logical ReasoningCapstone: Symbolizing, Proving, and Refuting Propositional ArgumentsPropositional Logic: Form, Connectives, and Valid InferenceEvaluating ArgumentsFoundations of Logical ReasoningSymbolizing Propositional ArgumentsNatural Deduction: Validity and Formal ProofThree Modes of ReasoningFoundations of Logical ReasoningTruth Tables, Equivalence, and ValidityPropositional Logic: Form, Connectives, and Valid InferenceValidity vs TruthNatural Deduction: Validity and Formal Proof