Modus tollens

From Simple English Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Modus tollendo tollens (Latin: the way that denies by denying)[1] is a valid, simple argument form in classical logic. It is referred to as denying the consequent. It is closely related to another valid form of argument, modus ponens or affirming the antecedent. Modus tollens is a very common rule of inference, and takes this form:

If P, then Q.
Not Q.
Therefore, not P.[2]

References[change | change source]

  1. Stone, Jon R. (1996). Latin for the Illiterati: exorcizing the ghosts of a dead language. London, UK: Routledge: 60.
  2. University of North Carolina, Philosophy Department, Logic Glossary.