 ##  [Principle of Indirect Proof](/principle-indirect-proof) 

  ##  [Principle of Indirect Proof](https://mathlogic.quantumdictionary.io/principle-indirect-proof-0) 

  
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- Natural &amp; Formal Sciences -

**Mathematics &amp; Logic Dictionary**

 
Definition

A proof method that establishes the truth of a proposition P by assuming its negation ¬P and deriving a contradiction; from the contradiction one concludes that P must hold (commonly called reductio ad absurdum or proof by contradiction in classical logic).