indirect proof

American  

noun

1. an argument for a proposition that shows its negation to be incompatible with a previously accepted or established premise.

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indirect proof British  

noun

1. logic maths proof of a conclusion by showing its negation to be self-contradictory; reductio ad absurdum Compare direct

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Example Sentences

See Examples For:

indirect proof

They have never been seen directly, though an indirect proof of their existence, based on studying a pair of collapsed stars, was rewarded with the 1993 Nobel prize in physics.

From Economist ● Mar. 20, 2014

I was about to begin going over the steps of indirect proof when I heard Danny say, “You’re always sleeping! What a sleepyhead you are!” and I opened my eyes.

From "The Chosen" by Chaim Potok

Such a proof is also called an indirect proof, but this term is not altogether satisfactory.

From The Teaching of Geometry by Smith, David Eugene

The considerations just adduced imply the immortality of the soul, to which they lend indirect proof.

From A History of Mediaeval Jewish Philosophy by Husik, Isaac

An indirect proof of this is given by the fact, that legal practice was labouring to discover means of protection for possession based on temporary agreement.

From Villainage in England Essays in English Mediaeval History by Vinogradoff, Paul