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

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

This was the first intimation the clerks had that he had left, and seems an indirect proof that no one in the office could have had anything to do with the tragedy.

From The Master Detective Being Some Further Investigations of Christopher Quarles by Brebner, Percy James

The indirect proof is drawn from the centripetal force in general, and the tendency that all bodies have in particular towards a centre of gravity.

From Astronomical Myths Based on Flammarions's History of the Heavens by Blake, John F.

But the indirect proof thus afforded that the actual Lectionary System must needs date from a period long anterior to our oldest Codexes is a far more important as well as a more interesting inference.

From The Causes of the Corruption of the Traditional Text of the Holy Gospels Being the Sequel to The Traditional Text of the Holy Gospels by Miller, Edward