Modus Tollendo Ponens

Sequent
Modus tollendo ponens is a valid argument in types of logic dealing with disjunctions $\lor$ and negation $\neg$.

This includes propositional logic and predicate logic, and in particular natural deduction.

Variants
The following forms can be used as variants of this theorem:

Variant
Note that the form:

requires Law of Excluded Middle.

Therefore it is not valid in intuitionistic logic.

Also see

 * Definition:Disjunction

The following are related argument forms:
 * Modus Ponendo Ponens
 * Modus Ponendo Tollens
 * Modus Tollendo Tollens