denying the consequent

Modus tollens (MT), or denying the consequent, is a rule of inference taking the form of “if P, then Q; not Q, therefore not P”.

Modus tollens is closely related to contraposition (). It can be proved by modus ponens.

Formal Notation

We can also write it in the sequent form:

See Also

• denying the antecedent (the logical fallacy of )