Michael Behe

In 1996, Behe published his ideas on irreducible complexity in his book Darwin's Black Box. Behe's refusal to identify the nature of any proposed intelligent designer frustrates scientists, who see it as a move to avoid any possibility of testing the positive claims of ID while allowing him and the intelligent design movement to distance themselves from some of the more overtly religiously motivated critics of evolution.[20]

As to the identity of the intelligent designer, Behe responds that if, deep in the woods, one were to come across a group of flowers that clearly spelled out the name "LEHIGH", one would have no doubt that the pattern was the result of intelligent design. Determining who the designer was, however, would not be nearly as easy.

In 1997, Russell Doolittle, on whose work Behe based much of the blood-clotting discussion in Darwin's Black Box, wrote a rebuttal to the statements about irreducible complexity of certain systems. In particular, Doolittle mentioned the issue of the blood clotting in his article, "A Delicate Balance."[21] Later on, in 2003, Doolittle's lab published a paper in the peer-reviewed journal Proceedings of the National Academy of Sciences which demonstrates that the pufferfish lacks at least three out of 26 blood clotting factors, yet still has a workable blood clotting system. According to Doolittle, this defeats a key claim in Behe's book, that blood clotting is irreducibly complex.[22]

In reviewing a book by Robert T. Pennock, Behe took issue with the "intelligent design" group being associated with "creationism," saying readers would typically take that to mean biblical literalism and young Earth creationism (YEC). In 2001 Pennock responded that he had been careful to represent their views correctly, and that while several leaders of the intelligent design movement were young Earth creationists, others including Behe were "old-earthers" and "creationists in the core sense of the term, namely, that they reject the scientific, evolutionary account of the origin of species and want to replace it with a form of special creation."[23]

In 2004, Behe published a paper with David Snoke, in the scientific journal Protein Science that uses a simple mathematical model to simulate the rate of evolution of proteins by point mutation,[24] which he states supports irreducible complexity, based on the calculation of the probability of mutations required for evolution to succeed. However, the paper does not mention intelligent design nor irreducible complexity, which were removed, according to Behe, at the behest of the reviewers. Nevertheless, the Discovery Institute lists it as one of the "Peer-Reviewed & Peer-Edited Scientific Publications Supporting the Theory of Intelligent Design."[25]

Michael Lynch authored a response,[26] to which Behe and Snoke responded.[27] Protein Science discussed the papers in an editorial.[28]

Numerous scientists have debunked the work, pointing out that not only has it been shown that a supposedly irreducibly complex structure can evolve, but that it can do so within a reasonable time even subject to unrealistically harsh restrictions, and noting that Behe and Snoke's paper does not properly include natural selection and genetic redundancy. When the issue raised by Behe and Snoke is tested in the modern framework of evolutionary biology, numerous simple pathways to complexity have been shown. In their response, Behe and Snoke assumed that intermediate mutations are always damaging, where modern science allows for neutral or positive mutations.[29] Some of the critics have also noted that the Discovery Institute continues to claim the paper as 'published evidence for design,' despite its offering no design theory nor attempting to model the design process, and therefore not providing an alternative to random chance.[30]

Many of Behe's statements have been challenged by biologist Kenneth R. Miller in his book, Finding Darwin's God (1999). Behe has subsequently disputed Miller's points in an online essay.[31]

In 2007, Behe's book The Edge of Evolution was published arguing that while evolution can produce changes within species, there is a limit to the ability of evolution to generate diversity, and this limit (the "edge of evolution") is somewhere between species and orders.

In this book Behe's central assertion is that Darwinian evolution actually exists but plays only a limited role in the development and diversification of life on Earth. To this aim, he examines the genetic changes undergone by the malaria plasmodium genome and the human genome in response to each other's biological defenses, and identifies that "the situation resembles trench warfare, not an arms race", by considering the hemoglobin-destroying, protein pump-compromising as a "war by attrition". Starting from this example, he takes into account the number of mutations required to "travel" from one genetic state to another, as well as population size for the organism in question. Then, Behe calculates what he calls the "edge of evolution", i.e., the point at which Darwinian evolution would no longer be an efficacious agent of creative biological change, arguing that purposeful design plays a major role in the development of biological complexity, through the mechanism of producing "non-random mutations", which are then subjected to the sculpting hand of natural selection .[32]

The book was reviewed, by prominent scientists in The New York Times,[33] The New Republic,[34] The Globe and Mail,[35] Science,[36] and Nature[37] who were highly critical of the work noting that Behe appears to accept almost all of evolutionary theory, barring random mutation, which is replaced with guided mutation at the hand of an unnamed designer.[32] The book earned Behe the Pigasus Award for the year 2007.

Behe also promotes intelligent design in his 2019 book, Darwin Devolves[38] whose central premise is that the combination of random mutation and natural selection, apart from being incapable of generating novelty, is mainly a degradative force. Like his previous books, Darwin Devolves received negative reviews from the scientific community, including a scathing review in Science by Nathan H. Lents, Richard Lenski, and S. Joshua Swamidass,[39] a harsh critique by Jerry Coyne in The Washington Post,[40] and a scholarly rebuttal in Evolution from Gregory Lang and Amber Rice, Behe's colleagues at Lehigh University.[41] Lents said of Darwin Devolves and The Edge of Evolution: "his [ ] two books totally missed their marks and were easily dismissed by the scientific community."[42]

Lang and Rice's assessment noted that while Behe rightfully acknowledges that organisms have common ancestry, it is posited that a designer is required for more distant relationships like at the family level, and that the presentation of degradative processes is exaggerated with evidence of beneficial adaptations dodged. The article also criticized the use of false analogies and neglecting evidence of new genetic raw material production for evolution ("Behe is correct that the loss of genetic information is an important mechanism. However, the opposing processes of gene duplication, horizontal gene transfer, and introgression balance out gene loss, providing a source of new genetic material"). They then concluded with examples of adaptation that contradict the book's conclusions and expound on the flaws of Irreducible Complexity, adding that "why evolution by natural selection is difficult for so many to accept is beyond the scope of this review; however, it is not for a lack of evidence."[41]

Behe has written for the Boston Review, The American Spectator, and The New York Times.

In Kitzmiller v. Dover Area School District, the first direct challenge brought in United States federal courts to an attempt to mandate the teaching of intelligent design on First Amendment grounds, Behe was called as a primary witness for the defense and asked to support the idea that intelligent design was legitimate science. Some of the most crucial exchanges in the trial occurred during Behe's cross-examination, where his testimony would prove devastating to the defense. Behe was forced to concede that "there are no peer reviewed articles by anyone advocating for intelligent design supported by pertinent experiments or calculations which provide detailed rigorous accounts of how intelligent design of any biological system occurred"[43] and that his definition of 'theory' as applied to intelligent design was so loose that astrology would also qualify.[44] Earlier during his direct testimony, Behe had argued that a computer simulation of evolution he performed with Snoke shows that evolution is not likely to produce certain complex biochemical systems. Under cross examination however, Behe was forced to agree that "the number of prokaryotes in 1 ton of soil are 7 orders of magnitude higher than the population [it would take] to produce the disulfide bond" and that "it's entirely possible that something that couldn't be produced in the lab in two years... could be produced over three and half billion years."[43][45][46]

Many of Behe's critics have pointed to these exchanges as examples they believe further undermine Behe's statements about irreducible complexity and intelligent design. John E. Jones III, the judge in the case, would ultimately rule that intelligent design is not scientific in his 139-page decision, citing Behe's testimony extensively as the basis for his findings:

• "Consider, to illustrate, that Professor Behe remarkably and unmistakably claims that the plausibility of the argument for ID depends upon the extent to which one believes in the existence of God."[47]
• "As no evidence in the record indicates that any other scientific proposition's validity rests on belief in God, nor is the Court aware of any such scientific propositions, Professor Behe's assertion constitutes substantial evidence that in his view, as is commensurate with other prominent ID leaders, ID is a religious and not a scientific proposition."[47]
• "First, defense expert Professor Fuller agreed that ID aspires to 'change the ground rules' of science and lead defense expert Professor Behe admitted that his broadened definition of science, which encompasses ID, would also embrace astrology. Moreover, defense expert Professor Minnich acknowledged that for ID to be considered science, the ground rules of science have to be broadened to allow consideration of supernatural forces."[48]
• "What is more, defense experts concede that ID is not a theory as that term is defined by the NAS and admit that ID is at best 'fringe science' which has achieved no acceptance in the scientific community."[49]
• "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."[50]
• "ID proponents primarily argue for design through negative arguments against evolution, as illustrated by Professor Behe's argument that 'irreducibly complex' systems cannot be produced through Darwinian, or any natural, mechanisms. However, … arguments against evolution are not arguments for design. Expert testimony revealed that just because scientists cannot explain today how biological systems evolved does not mean that they cannot, and will not, be able to explain them tomorrow. As Dr. Padian aptly noted, 'absence of evidence is not evidence of absence.'… Irreducible complexity is a negative argument against evolution, not proof of design, a point conceded by defense expert Professor Minnich."[51]
• "Professor Behe's concept of irreducible complexity depends on ignoring ways in which evolution is known to occur. Although Professor Behe is adamant in his definition of irreducible complexity when he says a precursor 'missing a part is by definition nonfunctional,' what he obviously means is that it will not function in the same way the system functions when all the parts are present. For example in the case of the bacterial flagellum, removal of a part may prevent it from acting as a rotary motor. However, Professor Behe excludes, by definition, the possibility that a precursor to the bacterial flagellum functioned not as a rotary motor, but in some other way, for example as a secretory system."[52]
• "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."[53]
• "In fact, 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."[54]
• "With ID, proponents assert that they refuse to propose hypotheses on the designer's identity, do not propose a mechanism, and the designer, he/she/it/they, has never been seen. ... In addition, Professor Behe agreed that for the design of human artifacts, we know the designer and its attributes and we have a baseline for human design that does not exist for design of biological systems. Professor Behe's only response to these seemingly insurmountable points of disanalogy was that the inference still works in science fiction movies."[55]

Jones would later say that Eric Rothschild's cross examination of Behe was "as good a cross-examination of an expert witness as I have ever seen. It was textbook."[56][57]

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Association of Christian Schools International v. Roman Sterns

Behe received $20,000 for testifying as an expert witness on behalf of the plaintiffs in Association of Christian Schools International v. Roman Stearns.[58] The case was filed by Association of Christian Schools International, which argued that the University of California was being discriminatory by not recognizing science classes that use creationist books.[58] The 2005 filing claimed that University of California's rejection of several of their courses was illegal "viewpoint discrimination and content regulation prohibited by the Free Speech Clause."[59] In 2007, Behe's expert witness report claimed that the Christian textbooks, including William S. Pinkston, Jr.'s Biology for Christian Schools (1980; 2nd ed. 1994), are excellent works for high school students. He defended that view in a deposition.[60][61]

In August 2008, Judge S. James Otero rejected Behe's claims, saying that Behe "submitted a declaration concluding that the BJU [Bob Jones University Press] text mentions standard scientific content. ... However, Professor Behe 'did not consider how much detail or depth' the texts gave to this standard content."[59] Otero ruled in favor of the University of California's decision to reject courses using these books.[59][62]