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reductio ad absurdum

"Reduction to the absurd;" the process of demonstrating that an idea is probably false by first assuming its truth, and then showing how that truth leads to conclusions which can't possibly be true. In A Mathematician's Apology (1941),1 G. H. Hardy said: "Reductio ad absurdum, which Euclid loved so much, is one of a mathematician's finest weapons. It is a far finer gambit than any chess play: a chess player may offer the sacrifice of a pawn or even a piece, but a mathematician offers the game."


  1. Hardy, G. H. A Mathematician's Apology. London: Cambridge University Press, 1941.

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