# Relationship between reductio ad absurdum and modus tollens

### Math Forum Discussions

There is some instability in the terminology here. Many authors use Reductio Ad Absurdum (RAA) as meaning the same as proof by contradiction and indirect. lus, only one of them, modus ponens, is clearly indemonstrable. Never- theless, I try to show . Where '→' stands for conditional relationship. In my view, it is not only linked in logic to Reductio ad Absurdum, but also to the Ex. Contradictione. general form of argument known as reductio ad absurdum. is the same as modus tollens, and the only difference between those three is.

### Modus tollens - Wikipedia

Сердечный приступ. Беккер безучастно кивнул: - Так мне сказали. Лейтенант вздохнул и сочувственно помотал головой.