Reductio ad absurdum

Reductio ad absurdum (Latin for "reduction to the absurd"), also known as an apagogical argument, reductio ad impossibile, or proof by contradiction, is a type of logical argument where one assumes a claim for the sake of argument and derives an absurd or ridiculous outcome, and then concludes that the original claim must have been wrong as it led to an absurd result.

It makes use of the law of non-contradiction — a statement cannot be both true and false. In some cases it may also make use of the law of excluded middle — a statement must be either true or false. The phrase is traceable back to the Greek Template:Polytonic (hē eis átopon apagōgḗ), meaning "reduction to the absurd", often used by Aristotle.

In mathematics and formal logic, this refers specifically to an argument where a contradiction is derived from some assumption (thus showing that the assumption must be false). However, Reductio ad absurdum is also often used to describe any argument where a conclusion is derived in the belief that everyone (or at least those being argued against) will accept that it is false or absurd. This is a comparatively weak form of reductio, as the decision to reject the premise requires that the conclusion is accepted as being absurd. Although a formal contradiction is by definition absurd (unacceptable), a weak reductio ad absurdum argument can be rejected simply by accepting the purportedly absurd conclusion. Such arguments also risk degenerating into strawman arguments, an informal fallacy caused when an argument or theory is twisted by the opposing side to appear ridiculous.

Last updated by Nelson Mar 5, 2009.

Forum

A relapse.....

Started by Belle Rose in Small Talk. Last reply by Unseen 37 minutes ago. 7 Replies

How do you cure Insanity???

Started by Belle Rose in Advice. Last reply by Belle Rose 1 hour ago. 61 Replies

The Elephant in the Room...

Started by Belle Rose in Small Talk. Last reply by Belle Rose 2 hours ago. 25 Replies

An awakening.....radical acceptance.....

Started by Belle Rose in Crime and Punishment. Last reply by Pope Beanie 4 hours ago. 2 Replies

Services we love!

We are in love with our Amazon

Book Store!

Gadget Nerd? Check out Giz Gad!

Advertise with ThinkAtheist.com

In need a of a professional web site? Check out the good folks at Clear Space Media

© 2014   Created by umar.

Badges  |  Report an Issue  |  Terms of Service