Is modus ponens a fallacy?
Modus ponens is not a logical fallacy; it is a valid form of deductive reasoning. Also known as “affirming the antecedent,” it employs a straightforward logical structure:
- If P, then Q.
- P.
- Therefore, Q.
However, flawed attempts at forming a syllogism often result in formal logical fallacies, such as denying the antecedent, which resembles modus ponens in form but fails to provide logical certainty:
- If P, then Q.
- Not P.
- Therefore, not Q.
Although the two arguments look similar, denying the antecedent is an invalid form of argument.