The Edge of Evolution

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The Edge of Evolution

Author	Michael J. Behe
Publisher	Free Press
Publication date	June 5, 2007
Media type	Hardcover/Audiobook (August 1, 2007)
Pages	336
ISBN	ISBN 0-743-29620-6

The Edge of Evolution: The Search for the Limits of Darwinism is a book promoting intelligent design by Discovery Institute fellow Michael Behe, published by the Free Press in 2007. In the book Behe argues 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. Thus, he asserts, known evolutionary mechanisms cannot be responsible for observed diversification from the last universal ancestor and thus only the intervention of a intelligent designer can adequately account for the diversity of life. It is Behe's second book that attempts to promote intelligent design, his first being his 1996 Darwin's Black Box, also published by Free Press.

Intelligent design has been overwhelmingly rejected by the scientific community and has been found by a United States district court to be a modern version of creationism.^[1] While the book has had some positive reviews from creationists and non-biologists,^[2]^[3] reviews by scientists, especially those working in the field of biology, have been highly critical of Behe's methods, information and conclusions in the book.^[4]^[5]^[6]^[7]

1 Contents
2 Reviews
- 2.1 Negative reviews
- 2.2 Positive reviews
3 Responses and scientific criticism
4 See also
5 References
6 External links

[edit] Contents

Behe's primary assertion is that the theory of evolution comprises three ideas that are assumed to depend on each other for coherence (common descent, natural selection, and random mutation) but are in fact distinct. Behe goes on to state his support for common descent and natural selection, but questions the scope and power of random mutation to produce beneficial mutations that lead to novel, useful structures and processes. He terms "Darwinian evolution" the type of evolution relying on all three of these factors, applies the label "Darwinists" to scientists who hold the view that Darwinian evolution is the only existing form of evolution, and who take exception to intelligent design as well as other theistic and non-theistic complexity theories.

Behe's central assertion regarding Darwinian evolution is that it exists, but that it is better at disturbing existing metabolic pathways (referred to as 'molecular machinery') than making new ones, and therefore plays only a limited role in the development and diversification of life on Earth. 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". He contrasts this hemoglobin-destroying, protein pump-compromising "war by attrition" with the "creative process" required to develop complex structures such as the bacterial flagellum as well as stupendously complex systems such as the immune system.

Behe calculates the "edge of evolution" - the point at which Darwinian evolution is no longer an efficacious agent of creative biological change - by taking 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. He concludes 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.

Design that favors the development of intelligent life, argues Behe, is not only demanded by "the most recent findings concerning biological complexity", but also by discoveries in the fields of chemistry (he uses the example of the peculiar, life-supporting structure of water), and of cosmology (referring to the anthropic principle).

Behe argues strongly for common descent of all lifeforms on earth, including conceding that humans and chimpanzees have a common ancestor. He states that there is such overwhelming evidence for common ancestry that it should not only be obvious, but "trivial". Behe claims that the mutations required for speciation is not possible without design, and that this is the "edge of evolution". The argument hinges on the purported low probability of an organism having two or more simultaneous mutations to yield some advantage for the organism.^[8]

Behe acknowledges his support for intelligent design represents a minority view within the scientific community, alluding to his awareness of this fact several times in the book. He implies that for this reason, he avoids detailed discussion about the nature of life's designer, and takes deliberate steps to distinguish himself from theYoung Earth creationism movement.

[edit] Reviews

Behe's methods, information and conclusions have been overwhelmingly rejected by the scientific community,^[1] and reviews by scientists, especially those working in the field of biology, have been highly critical,^[4]^[5]^[6]^[7] though some reviews from creationists and non-biologists have been more positive.^[2]^[3]

[edit] Negative reviews

University of Oxford evolutionary biologist Richard Dawkins reviewed the book, concentrating his criticism on Behe's claim that random mutation, rather than nonrandom natural selection was the driving force behind evolution. He also criticized Behe's claim that no amount of random mutation could bring about the diversity of life in existence today by pointing to several examples of selective breeding. Dawkins also states that Behe had failed to connect with the scientific research on his topic and that Behe's work would not pass the peer-review of a scientific journal and that Behe bypassed the peer-review process by publishing a popular book solely for a public, rather than scientific, audience.^[4]

The Edge of Evolution was reviewed, by prominent biologists, in The New Republic, Science and Nature with similar comments - 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.^[5]^[6]^[7]

Other reviews have criticized Behe for misleading quote mining,^[9] failing to offer a theory of intelligent design despite a ten-year gap since Darwin's Black Box,^[10] a logical contradiction between design and 'unbroken natural law',^[10] an erroneous model^[11] and ignoring publications and information that contradicts his theory.^[11] Singled out for specific criticism included the use of irrelevant calculations as sources, his assertion of the necessity of simultaneous mutations when evidence supports cumulative mutations, and ignoring the scientific literature on protein evolution.^[12] Michael Ruse, professor of philosophy at Florida State University, found the book to contain no developments beyond what was offered in Darwin's Black Box, repeating arguments, ignoring and dismissing opposing arguments without analysis;^[13] comments echoed by others.^[12] A review by Publishers Weekly praises the clarity and passion of Behe's writing, but criticizes him for a simplistic understanding of evolution, including the false assumption that it is a goal-directed process. The review goes on to state that his greatest error is the conclusion, without any evidence, that an intelligent designer as the only alternative to evolution.^[14] The Panda's Thumb has also reviewed the book, criticizing it for faulty math, extending the faulty assumptions made in an earlier paper, making gross generalizations about biology based on a limited number of examples without checking the relevant literature for counter-examples,^[15] PZ Myers reviewed the book at Pharyngula, stating that Behe rests his entire argument for a designer, unnamed yet responsible for the design of fundamental physical constants, the origins of life and all development of life beyond the level of intraspecies variation, on his theorized barriers to variation that could not be overcome without intelligent aid; the basis of this barrier being a single calculation of probability for a double-mutation on the malaria parasite responsible for chloroquine resistance.^[16] Myers also cites Behe's failure to acknowledge incremental changes and improvements in evolutionary developments, and points out that even the fundamental equation on which the book is based is actually flawed.^[17]

David E. Levin of the Department of Biochemistry and Molecular Biology at The Johns Hopkins Bloomberg School of Public Health writes that it is remarkable how much Behe embraces evolution in this book. Levin states that Behe repeats the same mistakes he made in his book Darwin's Black Box and demonstrated during the Kitzmiller v. Dover trial by assuming that mutations must all happen simultaneously and produce an irreducibly complex structure. Levin thinks that Behe continues to make arguments from ignorance, because Behe assumes that since he cannot imagine a use for a simpler structure with fewer components, one cannot exist. Levin states that the probability calculations that Behe relies on are wrong, since biological functions can be created stepwise, one mutation at a time, instead of requiring all mutations to happen simultaneously to confer some advantage on the organism.^[8]

[edit] Positive reviews

Historian of religion^[18] Cameron Wybrow wrote a review of Edge of Evolution published in The Philadelphia Inquirer, stating that the book "provides some hard numbers, coupled with an ingenious argument".^[3] Positive reviews also appeared in a variety of Christian publications, such as a one in the Christian Post by minister Chuck Colson, in which he states:

I suggest you ignore the forces that would stifle all dissent, and take a look at Behe’s book The Edge of Evolution. Even if you do not agree with everything in it, as I do not, you do not need to follow the Darwinist line that everything you disagree with must be squashed.

– Chuck Colson, What Darwinism Can't Do^[19]

Both Colson and Wybrow attacked the negative reviewers, claiming that editors had deliberately picked foes of intelligent design to review the book.

[edit] Responses and scientific criticism

Behe has replied to some of his critics on his blog at Amazon.com.^[20] Behe's critics have suggested that these responses have sidestepped scientific criticisms^[21]^[22] and have on one occasion employed sexist ad hominem attacks.^[22]^[23]^[24]

In response to criticism by Abbie Smith and Ian Musgrave, Behe agreed that his claim that HIV had evolved no new protein binding sites was incorrect and that at least one such binding site had evolved on the Vpu viroporin protein but Behe argued that the mistake did not alter the validity of his argument.^[22]^[25]^[26]

On The Panda's Thumb blog Ian Musgrave has stated that the book's "core concept ... that protein-protein binding sites are extremely unlikely to have developed by natural means" is undermined by a recent Science article^[27] whose authors were "able to produce strong protein-protein binding in many cases with a single mutation." Musgrave concludes:^[28]

Behe greatly overestimates the difficulty of developing a binding site, ignores the fact that the majority of 10,000 binding sites in modern vertebrates are duplicate copies of each other, with there being only a much smaller number of basic binding motifs and ignores the fact that most of these basic binding motifs were developed in rapidly dividing single celled organisms with very large populations.

Far from protein-protein binding pointing to an unknown designer, protein binding sites point directly to descent with modification and the "tinkering" of natural selection.