irreducible complexity

This article covers irreducible complexity as used by those who argue for intelligent design. For information on irreducible complexity as used in Systems Theory, see Irreducible complexity (Emergence).

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Irreducible complexity (IC) is an argument made by intelligent design proponents that certain biological systems are too complex to have evolved from simpler, or "less complete" predecessors, and are at the same time too complex to have arisen naturally through chance mutations. It is one of two main arguments intended to support intelligent design, the other being specified complexity.[1] The consensus of the scientific community is to reject intelligent design as not science,[2][3][4] but creationism.[5][6][7][8]

Biochemistry professor Michael Behe, the originator of the argument of irreducible complexity, defines an irreducibly complex system as one "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".[9] These examples are said to demonstrate that modern biological forms could not have evolved naturally. Behe is on record stating he believes in evolution, but does not think life evolved from next to nothing. The argument is used in a broader context to support the idea that an intelligent designer was involved, at some point, in the creation of life, against the theory of evolution as far as creating all life (Behe admits life has evolved over millions of years, but does not believe life began through random chance) which requires no designer. In a manner of speaking, the IC argument is a definition of the "designer", or at least "what was designed", a definition that has proven elusive in the past. The most common examples used in argument are the complexity of the eye, the blood clotting cascade, or the motor in a cell's flagellum.

The examples offered to support the irreducible complexity argument have generally been found to fail to meet the definition and intermediate precursor states have been identified for several structures purported to exhibit irreducible complexity.<ref name="Kitzmiller_ruling_ID_science" /> For instance, precursors to the flagellum's motor can be found being used as ionic channels within bacteria, known as the Type III Secretory System.[10] This is true for most of the structure of the flagellum in general; of the 42 proteins found in the flagellum, 40 have already been found in use in different biological pathways.[11] Even Behe's toy model used to illustrate the concept, the mouse trap, was countered by critics including biology professor John McDonald, who produced examples of how he considered the mousetrap to be "easy to reduce", eventually to a single part.[12] Critics consider that most, or all, of the examples were based on misunderstandings of the workings of the biological systems in question, and consider the low quality of these examples excellent evidence for the argument from ignorance. Irreducible complexity is generally dismissed by the scientific community;[13] it is often referred to as pseudoscience.[14]

Despite being discredited in the Dover trial where the court found in its ruling 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",[15] irreducible complexity has nevertheless remained a popular argument among advocates of intelligent design and other creationists.


The term "irreducible complexity" was originally defined by Behe as:

A single system which is composed of several interacting parts that contribute to the basic function, and where the removal of any one of the parts causes the system to effectively cease functioning". (Darwin's Black Box p9)

Supporters of intelligent design use this term to refer to biological systems and organs that they believe could not have come about by any series of small changes. They 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.

A second definition given by Behe (his "evolutionary definition") is as follows:

''An irreducibly complex evolutionary pathway is one that contains one or more unselected steps (that is, one or more necessary-but-unselected mutations). The degree of irreducible complexity is the number of unselected steps in the pathway.

Intelligent design advocate William Dembski gives this definition:

''A system performing a given basic function is irreducibly complex if it includes a set of well-matched, mutually interacting, nonarbitrarily individuated parts such that each part in the set is indispensable to maintaining the system's basic, and therefore original, function. The set of these indispensable parts is known as the irreducible core of the system. (No Free Lunch, 285)



The argument from irreducible complexity is a descendant of the teleological argument for God (the argument from design or from complexity). This states that because certain things in nature are very complicated, they must have been designed. William Paley famously argued, in his 1802 watchmaker analogy, that complexity in nature implies a God for the same reason that the existence of a watch implies the existence of a watchmaker. This argument has a long history, and can be traced back at least as far as Cicero's De natura deorum ii.34. [16] [17]

The idea that the interrelationship between parts of living things would have implications for their origins was raised by writers starting with Pierre Gassendi in the mid 17th century (De Generatione Animalium, chapter III); in the early 18th century, Nicolas Malebranche (De la recherche de la verité 6.2.4, 6th edition, 1712) used this idea to argue in favor of preformation (see homunculus), rather than full development (see epigenesis), of the individual embryo; and a similar argument about the origins of the individual was made by other 18th century students of natural history. In a different application, in the early 19th century Georges Cuvier used the concept of "correlation of parts" in establishing the anatomy of animals from fragmentary remains.[18][19]

While he did not originate the term, Charles Darwin identified the argument as a possible way to falsify a prediction of the theory of evolution at the outset. In The Origin of Species, he wrote, "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case."[20] Darwin's theory of evolution challenges the teleological argument by postulating an alternative explanation to that of an intelligent designer—namely, evolution by natural selection. The argument from irreducible complexity attempts to demonstrate that certain biological features cannot be purely the product of Darwinian evolution.

Hermann Muller, in the early 20th century, discussed a concept similar to irreducible complexity. However, far from seeing this as a problem for evolution, he described the "interlocking" of biological features as a consequence to be expected of evolution, which would lead to irreversibility of some evolutionary changes.[21]
Being thus finally woven, as it were, into the most intimate fabric of the organism, the once novel character can no longer be withdrawn with impunity, and may have become vitally necessary.[22]

In 1974, Young Earth Creationist Henry M. Morris introduced a similar concept in his book "Scientific Creationism" in which he wrote; "This issue can actually be attacked quantitatively, using simple principles of mathematical probability. The problem is simply whether a complex system, in which many components function unitedly together, and in which each component is uniquely necessary to the efficient functioning of the whole, could ever arise by random processes."[23]

In 1981, Ariel Roth, in defense of the creation science position in the trial McLean v. Arkansas, said of "complex integrated structures" that "This system would not be functional until all the parts were there ... How did these parts survive during evolution ...?"[24]

In 1985 Cairns-Smith wrote of "interlocking", "How can a complex collaboration between components evolve in small steps?" and used the analogy of the scaffolding in building an arch: "Surely there was 'scaffolding'. Before the multitudinous components of present biochemistry could come to lean together they had to lean on something else."[25]

An essay in support of creationism published in 1994 referred to bacterial flagella as showing "multiple, integrated components", where "nothing about them works unless every one of their complexly fashioned and integrated components are in place" and asked the reader to "imagine the effects of natural selection on those organisms that fortuitously evolved the flagella ... without the concommitant [sic] control mechanisms".[26][27]

An early concept of irreducibly complex systems comes from Ludwig von Bertalanffy, a 20th-century Austrian biologist.[28] He believed that complex systems must be examined as complete, irreducible systems in order to fully understand how they work. He extended his work on biological complexity into a general theory of systems in a book titled General Systems Theory. After James Watson and Francis Crick published the structure of DNA in the early 1950s, General Systems Theory lost many of its adherents in the physical and biological sciences.[29] However, Systems theory remained popular in the social sciences long after its demise in the physical and biological sciences.


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Michael Behe's controversial book Darwin's Black Box popularized the concept of irreducible complexity.
Michael Behe developed his ideas on the concept around 1992, in the early days of the 'wedge movement', and first presented his ideas about "irreducible complexity" in June 1993 when the "Johnson-Behe cadre of scholars" met at Pajaro Dunes in California.[30] He set out his ideas in the second edition of Of Pandas and People published in 1993, extensively revising Chapter 6 Biochemical Similarities with new sections on the complex mechanism of blood clotting and on the origin of proteins.[31]

He first used the term "irreducible complexity" in his 1996 book Darwin's Black Box, to refer to certain complex biochemical cellular systems. He posits that evolutionary mechanisms cannot explain the development of such "irreducibly complex" systems. Notably, Behe credits philosopher William Paley for the original concept, not von Bertalanffy, and suggests that his application of the concept to biological systems is entirely original. Intelligent design advocates argue that irreducibly complex systems must have been deliberately engineered by some form of intelligence.

In 2001, Michael Behe wrote: "[T]here is an asymmetry between my current definition of irreducible complexity and the task facing natural selection. I hope to repair this defect in future work." Behe specifically explained that the "current definition puts the focus on removing a part from an already functioning system", but the "difficult task facing Darwinian evolution, however, would not be to remove parts from sophisticated pre-existing systems; it would be to bring together components to make a new system in the first place". In the 2005 Kitzmiller v. Dover Area School District trial, Behe testified under oath that he "did not judge [the asymmetry] serious enough to [have revised the book] yet." [32]

Behe additionally testified that the presence of irreducible complexity in organisms would not rule out the involvement of evolutionary mechanisms in the development of organic life. He further testified that he knew of no earlier "peer reviewed articles in scientific journals discussing the intelligent design of the blood clotting cascade," but that there were "probably a large number of peer reviewed articles in science journals that demonstrate that the blood clotting system is indeed a purposeful arrangement of parts of great complexity and sophistication." [33] (The result of the trial was the ruling that "intelligent design is not science and is essentially religious in nature".)[34]

According to the theory of evolution, genetic variations occur without specific design or intent. The environment "selects" the variants that have the highest fitness, which are then passed on to the next generation of organisms. Change occurs by the gradual operation of natural forces over time, perhaps slowly, perhaps more quickly (see punctuated equilibrium). This process is able to adapt complex structures from simpler beginnings, or convert complex structures from one function to another (see spandrel). Most intelligent design advocates accept that evolution occurs through mutation and natural selection at the "micro level", such as changing the relative frequency of various beak lengths in finches, but assert that it cannot account for irreducible complexity, because none of the parts of an irreducible system would be functional or advantageous until the entire system is in place.

Behe uses the mousetrap as an illustrative example of this concept. A mousetrap consists of several interacting pieces—the base, the catch, the spring, the hammer. Behe contends that all of these must be in place for the mousetrap to work, and that the removal of any one piece destroys the function of the mousetrap. Likewise, biological systems require multiple parts working together in order to function. Intelligent design advocates claim that natural selection could not create from scratch those systems for which science is currently not able to find a viable evolutionary pathway of successive, slight modifications, because the selectable function is only present when all parts are assembled. Behe's original examples of irreducibly complex mechanisms included the bacterial flagellum of E. coli, the blood clotting cascade, cilia, and the adaptive immune system.

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Michael Behe believes that many aspects of life show evidence of design, using the mousetrap in an analogy which others dispute.<ref name="trap" />

Behe argues that organs and biological features which are irreducibly complex cannot be wholly explained by current models of evolution. He argues that:

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.

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 shown by TalkOrigins to be false.[35][36] 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 NAS has rejected Professor Behe’s claim for irreducible complexity..."[37]

Stated examples

Behe and others have suggested a number of biological features that they believe may be irreducibly complex.

Blood clotting cascade

Main article: Coagulation

The blood clotting cascade in vertebrates is a complex biological pathway that is given as an example of apparent irreducible complexity.[38]

The irreducible complexity argument assumes that the necessary parts of a system have always been necessary, and therefore could not have been added sequentially. However, in evolution, something which is at first merely advantageous can later become necessary. For example, one of the clotting factors that Behe listed as a part of the clotting cascade was later found to be absent in whales, demonstrating that it is not essential for a clotting system.[39] Many purportedly irreducible structures can be found in other organisms as much simpler systems that utilize fewer parts. These systems, in turn, may have had even simpler precursors that are now extinct. The "improbability argument" also misrepresents natural selection. It is correct to say that a set of simultaneous mutations that form a complex protein structure is so unlikely as to be unfeasible, but that is not what Darwin advocated. His explanation is based on small accumulated changes that take place without a final goal. Each step must be advantageous in its own right, although biologists may not yet understand the reason behind all of them -- for example, jawless fish accomplish blood clotting with just six proteins instead of the full 10.[40].


Main article: Evolution of the eye

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Often used as an example of irreducible complexity.
(a) A pigment spot
(b) A simple pigment cup
(c) The simple optic cup found in abalone
(d) The complex lensed eye of the marine snail and the octopus

The eye is a famous example of a supposedly irreducibly complex structure, due to its many elaborate and interlocking parts, seemingly all dependent upon one another. It is frequently cited by intelligent design and creationism advocates as an example of irreducible complexity. Behe used the "development of the eye problem" as evidence for intelligent design in Darwin's Black Box. Although Behe acknowledged that the evolution of the larger anatomical features of the eye have been well-explained, he claimed that the complexity of the minute biochemical reactions required at a molecular level for light sensitivity still defies explanation. Creationist Jonathan Sarfati has described the eye as evolutionary biologists' "greatest challenge as an example of superb 'irreducible complexity' in God's creation", specifically pointing to the supposed "vast complexity" required for transparency.[41]

In an oft-quoted passage from The Origin of Species, Charles Darwin himself acknowledged the eye's development as a difficulty for his theory, noting that "to suppose that the eye... could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree". However, he went on to note that, if gradual evolution of the eye could be shown to be possible, "the difficulty of believing that a perfect and complex eye could be formed by natural selection, though by our imagination, can hardly be considered real", and proceeded to roughly map a possible course for evolution through examples from gradually more complex eyes of various species.[42]

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The eyes of vertebrates (left) and invertebrates such as the octopus (right) developed independently: vertebrates evolved an inverted retina with a blind spot over their optic disc, whereas octopuses avoided this with a non-inverted retina.

Since Darwin's day, the eye's ancestry has become much better understood. Although learning about the construction of ancient eyes through fossil evidence is problematic due to the soft tissues leaving no imprint or remains, genetic and comparative anatomical evidence has increasingly supported the idea of a common ancestry for all eyes.[43][44][45]

As Behe admits, current evidence does suggest possible evolutionary lineages for the origins of the anatomical features of the eye, for example, that eyes originated as simple patches of photoreceptor cells that could detect the presence or absence of light, but not its direction. By developing a small depression for the photosensitive cells, the organisms obtained a better sense of the light's source, and by continuing to deepen the depression into a pit so that light would strike certain cells depending on its angle, increasingly precise visible information was possible. The aperture of the eye was then shrunk in order to focus the light, turning the eye into a pinhole camera and allowing the organism to dimly make out shapes—the nautilus is a modern example of an animal with such an eye. Finally, the protective layer of transparent cells over the aperture was differentiated into a crude lens, and the interior of the eye was filled with humours to assist in focusing images.[46][47][48] In this way, eyes are recognized by modern biologists as actually a relatively unambiguous and simple structure to evolve, and many of the major developments of the eye's evolution are believed to have taken place over only a few million years, during the Cambrian explosion.[49] However, according to Behe, the complexity of light sensitivity at the molecular level and the minute biochemical reactions required for those first "simple patches of photoreceptor[s]" still defies explanation.


Main article: Evolution of flagella
The flagella of certain bacteria constitute a molecular motor requiring the interaction of about 40 complex protein parts, and the absence of any one of these proteins causes the flagella to fail to function. Behe holds that the flagellum "engine" is irreducibly complex because if we try to reduce its complexity by positing an earlier and simpler stage of its evolutionary development, we get an organism which functions improperly.

Mainstream scientists regard this argument as having been largely disproved in the light of fairly recent research.[50] They point out that the basal body of the flagella has been found to be similar to the Type III secretory system (TTSS), a needle-like structure that pathogenic germs such as Salmonella and Yersinia pestis use to inject toxins into living eucaryote cells. The needle's base has many elements in common with the flagellum, but it is missing most of the proteins that make a flagellum work. Thus, this system seems to negate the claim that taking away any of the flagellum's parts would render it useless. This has caused Kenneth Miller to note that, "The parts of this supposedly irreducibly complex system actually have functions of their own." [51]

Response of the scientific community

Like intelligent design, the concept it seeks to support, irreducible complexity has failed to gain any notable acceptance within the scientific community. One science writer called it a "full-blown intellectual surrender strategy."[52]

Reducibility of "irreducible" systems

Potentially viable evolutionary pathways have been proposed for allegedly irreducibly complex systems such as blood clotting, the immune system[53] and the flagellum,[54][55] which were the three examples Behe used. Even his example of a mousetrap was shown to be reducible by John H. McDonald.<ref name="trap" /> If irreducible complexity is an insurmountable obstacle to evolution, it should not be possible to conceive of such pathways—Behe has remarked that such plausible pathways would defeat his argument.

Niall Shanks and Karl H. Joplin, both of East Tennessee State University, have shown that systems satisfying Behe's characterization of irreducible biochemical complexity can arise naturally and spontaneously as the result of self-organizing chemical processes.[56][57] They also assert that what evolved biochemical and molecular systems actually exhibit is "redundant complexity"—a kind of complexity that is the product of an evolved biochemical process. They claim that Behe overestimated the significance of irreducible complexity because of his simple, linear view of biochemical reactions, resulting in his taking snapshots of selective features of biological systems, structures and processes, while ignoring the redundant complexity of the context in which those features are naturally embedded. They also criticized his over-reliance of overly simplistic metaphors, such as his mousetrap. In addition, research published in the peer-reviewed journal Nature has shown that computer simulations of evolution demonstrate that it is possible for irreducible complexity to evolve naturally.[58]

It is illustrative to compare a mousetrap with a cat, in this context. Both normally function so as to control the mouse population. The cat has many parts that can be removed leaving it still functional; for example, its tail can be bobbed or it can be spayed. Comparing the cat and the mousetrap, then, one sees that the mousetrap (which is not alive) offers better evidence, in terms of irreducible complexity, for intelligent design than the cat. Even looking at the mousetrap analogy, several critics have described ways in which the parts of the mousetrap could have independent uses or could develop in stages, demonstrating that it is not irreducibly complex.[12]

Moreover, even cases where removing a certain component in an organic system will cause the system to fail do not demonstrate that the system couldn't have been formed in a step-by-step, evolutionary process. By analogy, stone arches are irreducibly complex—if you remove any stone the arch will collapse—yet we build them easily enough, one stone at a time, by building over scaffolding that is removed afterward. Similarly, naturally occurring arches of stone are formed by weathering away bits of stone from a large concretion that has formed previously.

Evolution can act to simplify as well as to complicate. This raises the possibility that seemingly irreducibly complex biological features may have been achieved with a period of increasing complexity, followed by a period of simplification.

In April 2006 a team led by Joe Thornton, assistant professor of biology at the University of Oregon's Center for Ecology and Evolutionary Biology, using techniques for resurrecting ancient genes, scientists for the first time reconstructed the evolution of an apparently irreducibly complex molecular system. The research was published in the April 7 issue of Science.[59]

It may be that irreducible complexity does not actually exist in nature, that the examples given by Behe and others are not in fact irreducibly complex, but can be explained in terms of simpler precursors. There has also been a theory that challenges irreducible complexity called facilitated variation. The theory has been presented in 2005 by Marc W. Kirschner, a professor and chair of Department of Systems Biology at Harvard Medical School, and John C. Gerhart, a professor in Molecular and Cell Biology, University of California, Berkeley. In their theory, they describe how certain mutation and changes can cause apparent irreducible complexity. Thus, seemingly irreducibly complex structures are merely "very complex", or they are simply misunderstood or misrepresented.

Gradual adaptation to new functions

The precursors of complex systems, when they are not useful in themselves, may be useful to perform other, unrelated functions. Evolutionary biologists argue that evolution often works in this kind of blind, haphazard manner in which the function of an early form is not necessarily the same as the function of the later form. The mammalian ear (derived from a jawbone) and the panda's thumb (derived from a wrist bone spur) are considered classic examples. A 2006 article in Nature[60] demonstrates intermediate states leading toward the development of the ear in a Devonian fish (about 360 million years ago). Furthermore, recent research shows that viruses play a heretofore unexpectedly great role in evolution by mixing and matching genes from various hosts.

Arguments for irreducibility often assume that things started out the same way they ended up—as we see them now. However, that may not necessarily be the case.

Regarding Behe's antibody example, we have the "marker" substance and the "killer" substance, that together hunt and kill marked invaders. Behe claims that by themselves, the marker and the killer are useless, and thus must have been made at the same time. The killer cannot kill what it cannot find and the marker has no ability to kill even if it can find a target.

However, under gradual replacement, a different marker may have started out as an independent hunter and killer. After a while, a helper killer joined this army because it had some nice specialties. However, this second killer still depended on the first one to find the target. Thus the first killer served as both a marker and a killer, and the second killer is just a killer, relying on the first to hunt.

Perhaps over time it is more efficient to have the second killer specialize in killing and the first specialize in marking, and so the first killer is replaced by a similar substance that is merely a marker (perhaps a better marker than the first dual-purpose one).

Thus, each step is an advantage, yet the final result is a dependent pair that does not resemble the proto-killer. This example can be laid out as:
A = original killer and marker
K = second killer
M = replacement marker
# A
# AK
# MK

All we see today is "MK". Opponents of irreducible complexity state that Behe erroneously assumes that if the structure ended up MK, then it must have started out as M or K by themselves.

Falsifiability and experimental evidence

Some critics, such as Jerry Coyne (professor of evolutionary biology at the University of Chicago) and Eugenie Scott (a physical anthropologist and executive director of the National Center for Science Education) have argued that the concept of irreducible complexity, and more generally, the theory of intelligent design is not falsifiable, and therefore, not scientific.

Behe argues that the theory that irreducibly complex systems could not have been evolved can be falsified by an experiment where such systems are evolved. For example, he posits taking bacteria with no flagella and imposing a selective pressure for mobility. If, after a few thousand generations, the bacteria evolved the bacterial flagellum, then Behe believes that this would refute his theory.

Other critics take a different approach, pointing to experimental evidence that they believe falsifies the argument for Intelligent Design from irreducible complexity. For example, Kenneth Miller cites the lab work of Barry G. Hall on E. coli, which he asserts is evidence that "Behe is wrong."[61]

Argument from ignorance

Intelligent design proponents attribute to an intelligent designer those biological structures they believe are irreducibly complex and where a natural explanation is absent or insufficient to account for them.[62] However, critics view irreducible complexity as a special case of the "complexity indicates design" claim, and thus see it as an argument from ignorance and God of the gaps argument.[63]

Eugenie Scott, along with Glenn Branch and other critics, has argued that many points raised by intelligent design proponents are arguments from ignorance.[64] Behe has been accused of using an "argument by lack of imagination", and Behe himself acknowledges that simply because scientists cannot currently see how an "irreducibly complex" organism could evolve, it does not prove that there is no possible way for it to have occurred.

Irreducible complexity is at its core an argument against evolution. If truly irreducible systems were found, the implication is that intelligent design is the correct explanation for their existence. However, this conclusion is based on the assumption that current evolutionary theory and intelligent design are the only two valid models to explain life, a false dilemma.[65]

Irreducible complexity in the Dover trial

While testifying at the Kitzmiller v. Dover Area School District trial Behe conceded that there are no peer-reviewed papers supporting his claims that complex molecular systems, like the bacterial flagellum, the blood-clotting cascade, and the immune system, were intelligently designed nor are there any peer-reviewed articles supporting his argument that certain complex molecular structures are "irreducibly complex." <ref name="Kitzmiller_ruling_ID_science" />

In the final ruling of Kitzmiller v. Dover Area School District, Judge Jones specifically singled out Behe and irreducible complexity[13]:
  • "Professor Behe admitted in "Reply to My Critics" that there was a defect in his view of irreducible complexity because, while it purports to be a challenge to natural selection, it does not actually address "the task facing natural selection." and that "Professor Behe wrote that he hoped to "repair this defect in future work..." (Page 73)
  • "As expert testimony revealed, the qualification on what is meant by "irreducible complexity" renders it meaningless as a criticism of evolution. (3:40 (Miller)). In fact, the theory of evolution proffers exaptation as a well-recognized, well-documented explanation for how systems with multiple parts could have evolved through natural means." (Page 74)
  • "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 NAS has rejected Professor Behe’s claim for irreducible complexity..." (Page 75)
  • "As irreducible complexity is only a negative argument against evolution, it is refutable and accordingly testable, unlike ID [Intelligent Design], by showing that there are intermediate structures with selectable functions that could have evolved into the allegedly irreducibly complex systems. (2:15-16 (Miller)). Importantly, however, the fact that the negative argument of irreducible complexity is testable does not make testable the argument for ID. (2:15 (Miller); 5:39 (Pennock)). Professor Behe has applied the concept of irreducible complexity to only a few select systems: (1) the bacterial flagellum; (2) the blood-clotting cascade; and (3) the immune system. Contrary to Professor Behe’s assertions with respect to these few biochemical systems among the myriad existing in nature, however, Dr. Miller presented evidence, based upon peer-reviewed studies, that they are not in fact irreducibly complex." (Page 76)
  • "...on cross-examination, Professor Behe was questioned concerning his 1996 claim that science would never find an evolutionary explanation for the immune system. He was presented with fifty-eight peer-reviewed publications, nine books, and several immunology textbook chapters about the evolution of the immune system; however, he simply insisted that this was still not sufficient evidence of evolution, and that it was not "good enough." (23:19 (Behe))." (Page 78)
  • "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. (17:45-46 (Padian); 3:99 (Miller)). Additionally, even if irreducible complexity had not been rejected, it still does not support ID as it is merely a test for evolution, not design. (2:15, 2:35-40 (Miller); 28:63-66 (Fuller)). We will now consider the purportedly “positive argument” for design encompassed in the phrase used numerous times by Professors Behe and Minnich throughout their expert testimony, which is the “purposeful arrangement of parts.” Professor Behe summarized the argument as follows: We infer design when we see parts that appear to be arranged for a purpose. The strength of the inference is quantitative; the more parts that are arranged, the more intricately they interact, the stronger is our confidence in design. The appearance of design in aspects of biology is overwhelming. Since nothing other than an intelligent cause has been demonstrated to be able to yield such a strong appearance of design, Darwinian claims notwithstanding, the conclusion that the design seen in life is real design is rationally justified. (18:90-91, 18:109-10 (Behe); 37:50 (Minnich)). As previously indicated, this argument is merely a restatement of the Reverend William Paley’s argument applied at the cell level. Minnich, Behe, and Paley reach the same conclusion, that complex organisms must have been designed using the same reasoning, except that Professors Behe and Minnich refuse to identify the designer, whereas Paley inferred from the presence of design that it was God. (1:6- 7 (Miller); 38:44, 57 (Minnich)). Expert testimony revealed that this inductive argument is not scientific and as admitted by Professor Behe, can never be ruled out. (2:40 (Miller); 22:101 (Behe); 3:99 (Miller))." (Pages 79-80)

Notes and references

1. ^ Forrest, Barbara (May,2007), Understanding the Intelligent Design Creationist Movement: Its True Nature and Goals. A Position Paper from the Center for Inquiry, Office of Public Policy, Washington, D.C.: Center for Inquiry, Inc., <[1] (retrieved on 2007-08-22).
2. ^
3. ^ See: 1) List of scientific societies rejecting intelligent design 2) . 3) The Discovery Institute's A Scientific Dissent From Darwinism petition begun in 2001 has been signed by "over 700 scientists" as of August 20, 2006. A four day A Scientific Support for Darwinism petition gained 7733 signatories from scientists opposing ID. The AAAS, the largest association of scientists in the U.S., has 120,000 members, and firmly rejects ID. More than 70,000 Australian scientists and educators condemn teaching of intelligent design in school science classes. List of statements from scientific professional organizations on the status intelligent design and other forms of creationism. According to the New York Times "There is no credible scientific challenge to the theory of evolution as an explanation for the complexity and diversity of life on earth." Dean, Cordelia. "Scientists Feel Miscast in Film on Life’s Origin", The New York Times, September 27, 2007. Retrieved on 2007-09-28. 
4. ^ Teachernet, Document bank. Creationism teaching guidance. UK Department for Children, Schools and Families (September 18, 2007). Retrieved on 2007-10-01. “The intelligent design movement claims there are aspects of the natural world that are so intricate and fit for purpose that they cannot have evolved but must have been created by an 'intelligent designer'. Furthermore they assert that this claim is scientifically testable and should therefore be taught in science lessons. Intelligent design lies wholly outside of science. Sometimes examples are quoted that are said to require an 'intelligent designer'. However, many of these have subsequently been shown to have a scientific explanation, for example, the immune system and blood clotting mechanisms.
Attempts to establish an idea of the 'specified complexity' needed for intelligent design are surrounded by complex mathematics. Despite this, the idea seems to be essentially a modern version of the old idea of the "God-of-the-gaps". Lack of a satisfactory scientific explanation of some phenomena (a 'gap' in scientific knowledge) is claimed to be evidence of an intelligent designer.
5. ^ "for most members of the mainstream scientific community, ID is not a scientific theory, but a creationist pseudoscience." Trojan Horse or Legitimate Science: Deconstructing the Debate over Intelligent Design, David Mu, Harvard Science Review, Volume 19, Issue 1, Fall 2005.
• "Creationists are repackaging their message as the pseudoscience of intelligent design theory." Professional Ethics Report, American Association for the Advancement of Science, 2001.

6. ^ Wise, D.U., 2001, Creationism's Propaganda Assault on Deep Time and Evolution, Journal of Geoscience Education, v. 49, n. 1, p. 30-35.
7. ^ Who Believes What? Clearing up Confusion over Intelligent Design and Young-Earth Creationism, Marcus R. Ross, Journal of Geoscience Education, v. 53, n. 3, May, 2005, p. 319-323
8. ^ The Creationists: From Scientific Creationism to Intelligent Design, Expanded Edition, Ronald L. Numbers, Harvard University Press, Cambridge, Massachusetts, November 30, 2006, ISBN 0674023390.
9. ^ Darwin's Black Box: The Biochemical Challenge to Evolution, Michael Behe, 1996, quoted in Irreducible Complexity and Michael Behe (retrieved 8 January 2006)
10. ^ The Flagellum Unspun
11. ^ Ode to the Flagellum, The Panda's Thumb, ScienceBlogs December 22, 2006.
12. ^ A reducibly complex mousetrap (graphics-intensive, requires JavaScript)
13. ^
14. ^ "for most members of the mainstream scientific community, ID is not a scientific theory, but a creationist pseudoscience." Trojan Horse or Legitimate Science: Deconstructing the Debate over Intelligent Design David Mu. Harvard Science Review, Volume 19, Issue 1, Fall 2005. Why Intelligent Design Isn't Intelligent Review of: Unintelligent Design, by Mark Perakh Mark D. Decker. College of Biological Sciences, General Biology Program, University of Minnesota Frequently Asked Questions About the Texas Science Textbook Adoption Controversy "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."
15. ^
16. ^ On the Nature of the Gods, translated by Francis Brooks, London: Methuen, 1896.
17. ^ See Henry Hallam's Introduction to the Literature of Europe part iii chapter iii paragraph 26 footnote u
18. ^ Andrew Pyle, Malebranche on Animal Generation: Preexistence and the Microscope, in Justin E.H. Smith, ed. (2006) The Problem of Animal Generation in Early Modern Philosophy ISBN 0-521-84077-5, pg 202-203
19. ^ The Chicken or the Egg
20. ^ Darwin, Charles (1859). On the Origin of Species. London: John Murray. page 189, Chapter VI
21. ^ Hermann J. Muller: Genetic variability, twin hybrids and constant hybrids, in a case of balanced lethal factors, Genetics 1918 3: 422-499, especially pages 463-464.
22. ^ Hermann J. Muller: Reversibility in evolution considered from the standpoint of genetics, Biological Reviews of the Cambridge Philosophical Society, 4(3) 1939, 261-280, quotation from page 272.
23. ^ Scientific Creationism, edited by Henry M. Morris, Master Books; General ed., 2nd ed edition (October 1974), ISBN-10: 0890510032 , page 59.
24. ^ Normal L. Geisler, A. F. Brooke II, Mark J. Keough, The Creator in the Courtroom: "Scopes II", Milford, MI: Mott Media, 1982. ISBN 978-0-88062-020-8, p. 146 [2]
25. ^ Pages 39, 58-64, A. G. Cairns-Smith, Seven Clues to the Origin of Life: A Scientific Detective Story, Cambridge: Cambridge University Press, 1985. ISBN 0-521-27522-9
26. ^ Richard D. Lumsden,Not So Blind A Watchmaker, Creation Research Society Quarterly, vol. 31 no. 1 (June, 1994), pages 13-22. Quotations from pages 13 and 20.
27. ^ Eugenie C. Scott and Nicholas J. Matzke, Biological design in science classrooms, Proceedings of the National Academy of Sciences, vol. 104 suppl. 1 (May 15, 2007), pp. 8669-8676. See page 8672.
28. ^ Ludwig von Bertalanffy (1952). Problems of Life: An Evaluation of Modern Biological and Scientific Thought, pg 148 ISBN 1-131-79242-4
29. ^ Chance and Necessity: An Essay on the Natural Philosophy of Modern Biology, Jacques Monod, 1971
30. ^ Barbara Forrest, The Wedge at Work. Talk Reason, Chapter 1 of the book "Intelligent Design Creationism and Its Critics" (MIT Press, 2001), Retrieved 2007-05-28.
31. ^ The New Pandas: Has Creationist Scholarship Improved? Comments on 1993 Revisions by Frank J. Sonleitner (1994)
Introduction: Of Pandas and People, the foundational work of the 'Intelligent Design' movement by Nick Matzke 2004,
Design on Trial in Dover, Pennsylvania by Nicholas J Matzke, NCSE Public Information Project Specialist
32. ^ Behe, Michael (2001). Reply to My Critics. See also Behe's testimonial in Kitzmiller v. Dover
33. ^ Behe, Michael 2005
34. ^
35. ^ Claim CA350: Professional literature is silent on the subject of the evolution of biochemical systems TalkOrigins Archive.
36. ^ Behe, Michael J. [1996]. Darwin's black box : the biochemical challenge to evolution, 72. ISBN 0684827549. “"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" 
37. ^ Kitzmiller v. Dover Area School District, December 2005. Page 74.
38. ^ Action, George "Behe and the Blood Clotting Cascade"
39. ^ Semba U, Shibuya Y, Okabe H, Yamamoto T (1998). "Whale Hageman factor (factor XII): prevented production due to pseudogene conversion". Thromb Res 90 (1): 31-7. PMID 9678675. 
40. ^ Creationism special: A sceptic's guide to intelligent design, New Scientist, 09 July 2005
41. ^ Sarfati, Jonathan (2000). Argument: 'Irreducible complexity', from Refuting Evolution (Answers in Genesis).
42. ^ Darwin, Charles (1859). On the Origin of Species. London: John Murray. pages 186ff, Chapter VI
43. ^ Halder, G., Callaerts, P. and Gehring, W.J. (1995). "New perspectives on eye evolution." Curr. Opin. Genet. Dev. 5 (pp. 602 –609).
44. ^ Halder, G., Callaerts, P. and Gehring, W.J. (1995). "Induction of ectopic eyes by targeted expression of the eyeless gene in Drosophila". Science 267 (pp. 1788–1792).
45. ^ Tomarev, S.I., Callaerts, P., Kos, L., Zinovieva, R., Halder, G., Gehring, W., and Piatigorsky, J. (1997). "Squid Pax-6 and eye development." Proc. Natl. Acad. Sci. USA, 94 (pp. 2421–2426).
46. ^ Fernald, Russell D. (2001). The Evolution of Eyes: Why Do We See What We See? Karger Gazette 64: "The Eye in Focus".
47. ^ Fernald, Russell D. (1998). Aquatic Adaptations in Fish Eyes. New York, Springer.
48. ^ Fernald, Russell D. (1997). The evolution of eyes." Brain Behav Evol. 50 (pp. 253–259).
49. ^ Conway-Morris, S. (1998). The Crucible of Creation. Oxford: Oxford University Press.
50. ^ Miller, Kenneth R. The Flagellum Unspun: The Collapse of "Irreducible Complexity" with reply here
51. ^ Manier, Jeremy Unlocking cell secrets bolsters evolutionists (Chicago Tribune, 2006 Feb 13)
52. ^ Mirsky, Steve Sticker Shock: In the beginning was the cautionary advisory Scientific American, Feb 2005
53. ^ Matt Inlay, 2002. "Evolving Immunity." In
54. ^ Nicholas J. Matzke, 2003. "Evolution in (Brownian) space: a model for the origin of the bacterial flagellum."
55. ^ Mark Pallen and Nicholas J. Matzke, 2006, "From The Origin of Species to the origin of bacterial flagella." Nature Reviews Microbiology, 4(10), 784-790.
56. ^ Shanks, Niall Redundant Complexity:A Critical Analysis of Intelligent Design in Biochemistry
57. ^ Niall Shanks and Karl H. Joplin. Redundant Complexity:A Critical Analysis of Intelligent Design in Biochemistry. East Tennessee State University.
58. ^ Lenski RE, Ofria C, Pennock RT, Adami C (2003). "The evolutionary origin of complex features". Nature 423 (6936): 139-44. PMID 12736677. 
59. ^ Press release University of Oregon, April 4, 2006.
60. ^ M. Brazeau and P. Ahlberg (Jan 19, 2006). "Tetrapod-like middle ear architecture in a Devonian fish". Nature 439 (7074): 318-321. doi:10.1038/nature04196. 
61. ^ Finding Darwin's God Kenneth Miller. Harper Collins, 1999
62. ^ Michael Behe. Evidence for Intelligent Design from Biochemistry. 1996.[3]
63. ^ Index to Creationist Claims. Mark Isaak. The Talk.Origins Archive. "Irreducible complexity and complex specified information are special cases of the "complexity indicates design" claim; they are also arguments from incredulity." [4] "The argument from incredulity creates a god of the gaps." [5]
64. ^ Eugenie C. Scott and Glenn Branch, "Intelligent Design" Not Accepted by Most Scientists, National Center for Science Education website, September 10, 2002.
65. ^ IC and Evolution makes the point that: if "irreducible complexity" is tautologically redefined to allow a valid argument that intelligent design is the correct explanation for life then there is no such thing as "irreducible complexity" in the mechanisms of life; while, if we use the unmodified original definition then "irreducible complexity" has nothing whatever to do with evolution.
66. ^

Additional references

  • Behe, Michael (1996). Darwin's Black Box. New York: The Free Press. ISBN 0-684-83493-6
  • Denton, Michael (1986). . Adler & Adler.
  • Macnab RM (2004). "Type III flagellar protein export and flagellar assembly". Biochim Biophys Acta 1694 (1-3): 207-17. PMID 15546667. 
  • Ruben, J.A.; Jones, T.D.; Geist, N.R.; & Hillenius, W.J. (November 14, 1997). "Lung Structure and Ventilation in Theropod Dinosaurs and Early Birds". Science 278 (5341): 1267–1270. doi:10.1126/science.278.5341.1267.1997&rft.volume=278&rft.issue=5341&,%20J.A.%3B%20Jones,%20T.D.%3B%20Geist,%20N.R.%3B%20%26%20Hillenius,%20W.J.&rft.pages=1267%26ndash%3B1270"> 
  • Sunderland, Luther D. (March 1976). Miraculous Design in Woodpeckers. Creation Research Society Quarterly.
  • Testing Darwin Discover Magazine Vol. 26 No. 02 | February 2005

External links

In support
In opposition
Intelligent design is the assertion that "certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection.
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Systems theory is an interdisciplinary field of science. It studies the nature of complex systems in nature, society, and science. More specificially, it is a framework by which one can analyze and/or describe any group of objects that work in concert to produce some result.
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For a gentler introduction, see P = NP problem.

NP-hard (nondeterministic polynomial-time hard), in computational complexity theory, is a class of problems informally "at least as hard as the hardest problems in NP.
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Intelligent design is the assertion that "certain features of the universe and of living things are best explained by an intelligent cause, not an undirected process such as natural selection.
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Specified complexity is an argument proposed by William Dembski and used by him in his works promoting intelligent design. According to Dembski, the concept is intended to formalize a property that singles out patterns that are both specified and complex.
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fine-tuned Universe is the idea that conditions that allow life in the Universe can only occur with the tightly restricted values of the universal physical constants, and that small changes in these constants would correspond to a very different universe, not likely
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An intelligent designer, also referred to as an intelligent agent, is the willed and self-conscious entity that the intelligent design movement argues had some role in the origin and/or development of life and who supposedly has left scientific evidence of this
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Intelligent design

Irreducible complexity
Specified complexity
Fine-tuned universe
Intelligent designer
Theistic realism
Intelligent design

Discovery Institute
Center for Science and Culture
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intelligent design movement is a neo-creationist religious campaign that calls for broad social, academic and political changes derived from the concept of "intelligent design.
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This timeline of intelligent design outlines the major events in the development of intelligent design as presented and promoted by the intelligent design movement.

Creationism and Creation science

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The Discovery Institute is a think tank based in Seattle, Washington, best known for its advocacy of intelligent design and its Teach the Controversy campaign to teach creationist beliefs in United States public high school
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The Center for Science and Culture (CSC), formerly known as the Center for Renewal of Science and Culture (CRSC), is part of the Discovery Institute, a conservative Christian think tank[1] in the United States.
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The wedge strategy is a political and social action plan authored by the Discovery Institute, the hub of the intelligent design movement. The strategy was put forth in a Discovery Institute manifesto known as the Wedge Document,[1]
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Critical Analysis of Evolution is the name of a proposed high school science lesson plan designed and put forth by the Discovery Institute, originators of the intelligent design movement, as part of their campaign promoting
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Teach the Controversy is the name of a Discovery Institute intelligent design campaign to promote intelligent design, a variant of traditional creationism, while discrediting evolution in United States public high school
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History of creationism

Types of creationism
Day-age creationism
Gap creationism
Old Earth creationism
Progressive creationism
Theistic evolution
Young Earth creationism

Other religious views
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The Santorum Amendment was an amendment to the 2001 education funding bill which became known as the No Child Left Behind Act, proposed by former Republican United States Senator Rick Santorum from Pennsylvania, which promotes
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The reaction of Jewish leaders and organizations to intelligent design has been primarily concerned with responding to proposals to include intelligent design in the public school curriculum as a rival scientific hypothesis to
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The position of the Catholic Church on the theory of evolution has changed over the last two centuries from a large period of no official mention, to a statement of neutrality in the 1950s, to a more explicit acceptance in recent years.
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American Association for the Advancement of Science, the world's largest general scientific society, the AAAS serves some 262 affiliated societies and academies of science, serving 10 million individuals "[T]he lack of scientific warrant for so-called 'intelligent design theory'
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Creationism is a religious belief that humanity, life, the Earth, and the universe were created in their original form by a deity or deities (often the Abrahamic God of Judaism, Christianity and Islam), whose existence is presupposed.
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The history of creationism is tied to the history of religions. The term creationism in its broad sense covers a wide range of beliefs and interpretations, and was not in common use before the late 19th century.
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Neo-creationism is a movement whose goal is to restate creationism in terms more likely to be well received by the public, policy makers, educators, and the scientific community.
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Day-Age Creationism, a type of Old Earth creationism, is an effort to reconcile the literal Genesis account of Creation with modern scientific theories on the age of the Universe, the Earth, life, and humans.
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Gap creationism, also called Restitution creationism or Ruin-Reconstruction, are terms used to describe a particular set of Christian beliefs about the creation of the Universe and the origin of man.
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Old Earth creationism is a variant of the creationist view of the origin of the universe and life on Earth. As a theory of origins it is typically more compatible with mainstream scientific thought on the issues of geology, cosmology
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Progressive creationism is a form of Old Earth creationism that accepts mainstream geological and cosmological estimates for the age of the Earth, but posits that the new "kinds" of plants and animals that have appeared successively
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Theistic evolution, less commonly known as evolutionary creationism, is the general opinion that some or all classical religious teachings about God and creation are compatible with some or all of the modern scientific
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Young Earth creationism is a form of creationism that teaches that the Earth and life on Earth were created by a direct act of God dating between 6,000 and 10,000 years ago.
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