modus tollens

 
Pronunciation: /ˌməʊdəs ˈtɒlɛnz/

noun

  • the rule of logic which states that if a conditional statement (‘if p then q’) is accepted, and the consequent does not hold (not-q) then the negation of the antecedent (not-p) can be inferred.
  • an argument using the rule of modus tollens.

Origin:

Latin, literally 'mood that denies'