Valid Argument Forms and Formal Fallacies

Vocabulary flashcards covering valid deductive argument forms and formal fallacies in propositional logic.

Hypothetical Syllogism (VALID)

A valid argument form structured as: Premise 1: If P then Q ($p \rightarrow q$); Premise 2: If Q then R ($q \rightarrow r$); Conclusion: If P then R ($p \rightarrow r$).

Constructive Dilemma (VALID)

A valid argument form structured as: Premise 1: If P then Q ($p \rightarrow q$); Premise 2: If R then S ($r \rightarrow s$); Premise 3: Either P or R ($p \lor r$); Conclusion: Either Q or S ($q \lor s$).

Destructive Dilemma (VALID)

A valid argument form structured as: Premise 1: If P then Q ($p \rightarrow q$); Premise 2: If R then S ($r \rightarrow s$); Premise 3: Either not Q or Not S ($\sim q \lor \sim s$); Conclusion: Either not P or not R ($\sim p \lor \sim r$).

Fallacy of Affirming the Consequent (INVALID)

An invalid argument form structured as: Premise 1: If P then Q ($p \rightarrow q$); Premise 2: Q ($q$); Conclusion: P ($p$).

Fallacy of Denying the Antecedent (INVALID)

An invalid argument form structured as: Premise 1: If P then Q ($p \rightarrow q$); Premise 2: Not P ($\sim p$); Conclusion: Not Q ($\sim q$).