<logic, philosophy of science> circular reasoning. The "informal fallacy" of (explicitly or implicitly) assuming the truth of the conclusion of an argument as one of the premises employed in an effort to demonstrate its truth. Example: "Since firefighters must be strong men willing to face danger every day, it follows that no woman can be a firefighter." Although arguments of this sort are formally valid because it is impossible for their conclusions to be false if their premises are true, they fail to provide logical support for their conclusions, which have already been accepted without proof at the outset. Known also as petitio principii. Recommended Reading: Douglas N. Walton, Begging the Question (Greenwood, 1991).
[A Dictionary of Philosophical Terms and Names]
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