Editing Irreducible complexity (section)

=== Consequences ===

Supporters of intelligent design argue that anything less than the complete form of such a system or organ would not work at all, or would in fact be a ''detriment'' to the organism, and would therefore never survive the process of natural selection. Although they accept that some complex systems and organs ''can'' be explained by evolution, they claim that organs and biological features which are ''irreducibly complex'' cannot be explained by current models, and that an intelligent designer must have created life or guided its evolution. Accordingly, the debate on irreducible complexity concerns two questions: whether irreducible complexity can be found in nature, and what significance it would have if it did exist in nature.<ref>{{Cite web|last=Than|first=Ker|title=Why scientists dismiss 'intelligent design'|url=https://www.nbcnews.com/id/wbna9452500|access-date=2021-10-14|website=NBC News|language=en}}</ref>

Behe's original examples of irreducibly complex mechanisms included the bacterial [[flagellum]] of ''[[Escherichia coli|E. coli]]'', [[coagulation|the blood clotting cascade]], [[cilia]], and the [[adaptive immune system]].

Behe argues that organs and biological features which are irreducibly complex cannot be wholly explained by current models of [[evolution]]. In explicating his definition of "irreducible complexity" he notes that:
<blockquote>An irreducibly complex system cannot be produced directly (that is, by continuously improving the initial function, which continues to work by the same mechanism) by slight, successive modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional.</blockquote>

Irreducible complexity is not an argument that evolution does not occur, but rather an argument that it is "incomplete". In the last chapter of ''[[Darwin's Black Box]]'', Behe goes on to explain his view that irreducible complexity is evidence for [[intelligent design]]. Mainstream critics, however, argue that irreducible complexity, as defined by Behe, can be generated by known evolutionary mechanisms. Behe's claim that no scientific literature adequately modeled the origins of biochemical systems through evolutionary mechanisms has been challenged by [[TalkOrigins Archive|TalkOrigins]].<ref>[http://www.talkorigins.org/indexcc/CA/CA350.html Claim CA350: Professional literature is silent on the subject of the evolution of biochemical systems] {{webarchive|url=https://web.archive.org/web/20070304172657/http://www.talkorigins.org/indexcc/CA/CA350.html |date=2007-03-04 }} TalkOrigins Archive.</ref><ref>{{cite book |last= Behe |first= Michael J. |author-link= Michael Behe |title= Darwin's black box: the biochemical challenge to evolution |isbn= 978-0-684-82754-4 |page= 72 |quote= Yet here again the evolutionary literature is totally missing. No scientist has ever published a model to account for the gradual evolution of this extraordinary molecular machine. |year= 1996 |publisher= Free Press |location= New York, NY |orig-year= 1996}}</ref> The judge in the ''Dover'' trial wrote "By defining irreducible complexity in the way that he has, Professor Behe attempts to exclude the phenomenon of [[exaptation]] by definitional fiat, ignoring as he does so abundant evidence which refutes his argument. Notably, the [[United States National Academy of Sciences|NAS]] has rejected Professor Behe's claim for irreducible complexity..."<ref name=kitz74>[[s:Kitzmiller v. Dover Area School District/4:Whether ID Is Science#Page 74 of 139|Ruling]], [[Kitzmiller v. Dover Area School District]], December 2005. Page 74.</ref>