reductio ad absurdum Definition

reductio ad absurdum
noun

1. A way of proving that a premise is wrong by showing that its logical consequence is absurd.
2. A way of indirectly proving a premise by showing the logical consequence of its contradictory to be absurd.
3. The application of a principle or rule so strictly that it is carried to absurd lengths.

Etymology: 18c: Latin, meaning ‘reduction to the absurd'.