Irreducible complexity

Irreducible complexity (IC) is the argument that certain biological systems with multiple interacting parts would not function if one of the parts were removed, so supposedly could not have evolved by successive small modifications from earlier less complex systems through natural selection, which would need all intermediate precursor systems to have been fully functional.^[1] This negative argument is then complemented by the claim that the only alternative explanation is a "purposeful arrangement of parts" inferring design by an intelligent agent.^[2] Irreducible complexity has become central to the creationist concept of intelligent design (ID), but the concept of irreducible complexity has been rejected by the scientific community,^[3] which regards intelligent design as pseudoscience.^[4] Irreducible complexity and specified complexity, are the two main arguments used by intelligent-design proponents to support their version of the theological argument from design.^[2]^[5]

The central concept, that complex biological systems which require all their parts to function could not evolve by the incremental changes of natural selection so must have been produced by an intelligence, was already featured in creation science.^[6]^[7] The 1989 school textbook Of Pandas and People introduced the alternative terminology of intelligent design, a revised section in the 1993 edition of the textbook argued that a blood-clotting system demonstrated this concept.^[2]^[8]

This section was written by Michael Behe, a professor of biochemistry at Lehigh University. He subsequently introduced the expression irreducible complexity along with a full account of his arguments, in his 1996 book Darwin's Black Box, and said it made evolution through natural selection of random mutations impossible, or extremely improbable.^[2]^[1] This was based on the mistaken assumption that evolution relies on improvement of existing functions, ignoring how complex adaptations originate from changes in function, and disregarding published research.^[2] Evolutionary biologists have published rebuttals showing how systems discussed by Behe can evolve.^[9]^[10]

In the 2005 Kitzmiller v. Dover Area School District trial, Behe gave testimony on the subject of irreducible complexity. The court found that "Professor Behe's claim for irreducible complexity has been refuted in peer-reviewed research papers and has been rejected by the scientific community at large."^[3]

^ ^a ^b Behe, M.J. (2006). Darwin's Black Box: The Biochemical Challenge to Evolution. Touchstone book (2 ed.). Free Press. p. 39. ISBN 978-0-684-82754-4. Retrieved 16 July 2023. By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. 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. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since natural selection can only choose systems that are already working, then if a biological system cannot be produced gradually it would have to arise as an integrated unit, in one fell swoop, for natural selection to have anything to act on. (originally published 1996).
^ ^a ^b ^c ^d ^e Cite error: The named reference bio design classrooms was invoked but never defined (see the help page).
^ ^a ^b "We therefore find that Professor Behe's claim for irreducible complexity has been refuted in peer-reviewed research papers and has been rejected by the scientific community at large." 4:Whether ID Is Science, in E. Application of the Endorsement Test to the ID Policy, Ruling, Judge John E. Jones III, Kitzmiller v. Dover Area School District
^ "True in this latest creationist variant, advocates of so-called intelligent design ... use more slick, pseudoscientific language. They talk about things like "irreducible complexity" Shulman, Seth (2006). Undermining science: suppression and distortion in the Bush Administration. Berkeley: University of California Press. p. 13. ISBN 978-0-520-24702-4. "for most members of the mainstream scientific community, ID is not a scientific theory, but a creationist pseudoscience."
Mu, David (Fall 2005). "Trojan Horse or Legitimate Science: Deconstructing the Debate over Intelligent Design" (PDF). Harvard Science Review. 19 (1). Archived from the original (PDF) on 2007-07-24.
Perakh, M (Summer 2005). "Why Intelligent Design Isn't Intelligent — Review of: Unintelligent Design". Cell Biol. Educ. 4 (2): 121–2. doi:10.1187/cbe.05-02-0071. PMC 1103713.
Mark D. Decker. College of Biological Sciences, General Biology Program, University of Minnesota Frequently Asked Questions About the Texas Science Textbook Adoption Controversy^[usurped] "The Discovery Institute and ID proponents have a number of goals that they hope to achieve using disingenuous and mendacious methods of marketing, publicity, and political persuasion. They do not practice real science because that takes too long, but mainly because this method requires that one have actual evidence and logical reasons for one's conclusions, and the ID proponents just don't have those. If they had such resources, they would use them, and not the disreputable methods they actually use."
See also list of scientific societies explicitly rejecting intelligent design
^ Than, Ker (September 23, 2005). "Why scientists dismiss 'intelligent design' – LiveScience". NBC News. Retrieved 2010-05-17.
^ Scott 2009, pp. 123, 126 "The biochemist Michael Behe contends that intelligence is required to produce irreducibly complex cellular structures (ones that couldn't function if a single part were removed) because such structures could not have been produced by the incremental additions of natural selection (Behe 1996). ... More important than whether irreducibly complex structures actually occur other than by definition, however, is the critical question of whether they can be produced by natural mechanisms. Behe answers no, claiming that natural selection, the main mechanism of evolutionary change, is inadequate to the task. He views natural selection as assembling a complex structure by stringing together components one at a time, with each addition requiring a selective advantage. .... Behe's idea of irreducible complexity was anticipated in creation science; much as in Paley's conception, creation science proponents hold that structures too complex to have occurred 'by chance' require special creation."
^ Cite error: The named reference Slack 2008 p. 173 was invoked but never defined (see the help page).
^ Cite error: The named reference flare-up 2006 was invoked but never defined (see the help page).
^ Cite error: The named reference thornton2006 was invoked but never defined (see the help page).
^ Cite error: The named reference Redundant Complexity was invoked but never defined (see the help page).

[Behe_1996_p._39-1] Behe, M.J. (2006). Darwin's Black Box: The Biochemical Challenge to Evolution. Touchstone book (2 ed.). Free Press. p. 39. ISBN 978-0-684-82754-4. Retrieved 16 July 2023. By irreducibly complex I mean a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning. 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. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since natural selection can only choose systems that are already working, then if a biological system cannot be produced gradually it would have to arise as an integrated unit, in one fell swoop, for natural selection to have anything to act on. (originally published 1996).

[bio_design_classrooms-2] Cite error: The named reference bio design classrooms was invoked but never defined (see the help page).

[dover_behe_ruling-3] "We therefore find that Professor Behe's claim for irreducible complexity has been refuted in peer-reviewed research papers and has been rejected by the scientific community at large." 4:Whether ID Is Science, in E. Application of the Endorsement Test to the ID Policy, Ruling, Judge John E. Jones III, Kitzmiller v. Dover Area School District

[4] "True in this latest creationist variant, advocates of so-called intelligent design ... use more slick, pseudoscientific language. They talk about things like "irreducible complexity" Shulman, Seth (2006). Undermining science: suppression and distortion in the Bush Administration. Berkeley: University of California Press. p. 13. ISBN 978-0-520-24702-4. "for most members of the mainstream scientific community, ID is not a scientific theory, but a creationist pseudoscience."
Mu, David (Fall 2005). "Trojan Horse or Legitimate Science: Deconstructing the Debate over Intelligent Design" (PDF). Harvard Science Review. 19 (1). Archived from the original (PDF) on 2007-07-24.
Perakh, M (Summer 2005). "Why Intelligent Design Isn't Intelligent — Review of: Unintelligent Design". Cell Biol. Educ. 4 (2): 121–2. doi:10.1187/cbe.05-02-0071. PMC 1103713.
Mark D. Decker. College of Biological Sciences, General Biology Program, University of Minnesota Frequently Asked Questions About the Texas Science Textbook Adoption Controversy^[usurped] "The Discovery Institute and ID proponents have a number of goals that they hope to achieve using disingenuous and mendacious methods of marketing, publicity, and political persuasion. They do not practice real science because that takes too long, but mainly because this method requires that one have actual evidence and logical reasons for one's conclusions, and the ID proponents just don't have those. If they had such resources, they would use them, and not the disreputable methods they actually use."
See also list of scientific societies explicitly rejecting intelligent design

[LiveScience-_msnbc.com-5] Than, Ker (September 23, 2005). "Why scientists dismiss 'intelligent design' – LiveScience". NBC News. Retrieved 2010-05-17.

[Scott_2009_p._126-6] Scott 2009, pp. 123, 126 "The biochemist Michael Behe contends that intelligence is required to produce irreducibly complex cellular structures (ones that couldn't function if a single part were removed) because such structures could not have been produced by the incremental additions of natural selection (Behe 1996). ... More important than whether irreducibly complex structures actually occur other than by definition, however, is the critical question of whether they can be produced by natural mechanisms. Behe answers no, claiming that natural selection, the main mechanism of evolutionary change, is inadequate to the task. He views natural selection as assembling a complex structure by stringing together components one at a time, with each addition requiring a selective advantage. .... Behe's idea of irreducible complexity was anticipated in creation science; much as in Paley's conception, creation science proponents hold that structures too complex to have occurred 'by chance' require special creation."

[Slack_2008_p._173-7] Cite error: The named reference Slack 2008 p. 173 was invoked but never defined (see the help page).

[flare-up_2006-8] Cite error: The named reference flare-up 2006 was invoked but never defined (see the help page).

[thornton2006-9] Cite error: The named reference thornton2006 was invoked but never defined (see the help page).

[Redundant_Complexity-10] Cite error: The named reference Redundant Complexity was invoked but never defined (see the help page).

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