A propos du livre de Behe: The Edge of Evolution

[Jean-Francois]

Bonjour, est-ce que quelqu'un aurait un accès au New York Times? Je cherche un article critique de R. Dawkins sur le nouveau livre de M. Behe "The Edge of Evolution". On en trouve quelques passages ici mais j'aimerai le lire entièrement si possible.

A mon avis, les arguments que l'on trouve sur la page de Pharyngula démontent assez bien les affirmations de Julien sur l'impossibilité des mutations "bénéfiques": si elle étaient aussi impossibles que Julien le prétend, la sélection intelligente humaine n'aurait pu façonner autant d'espèces domestiques (de chiens ou autres) par des moyens "naturels".

Le livre de Behe s'est fait pasablement éreinter dans Nature, dans une critique de K.R. Miller (28 (2007): 1055-1056; voir ici (demande sans doute un abonnement)). Miller dénonce aussi les pseudo-calculs qui ne visent, contre toutes observations, qu'à laisser-croire à l'impossibilité de l'évolution. Il prend un exemple de Behe concernant l'acquisition d'une résistance de l'agent causant de la malaria à un antibiotique:
"Behe cites the malaria literature to note that two amino-acid changes in the digestive-vacuole membrane protein PfCRT (at positions 76 and 220) of Plasmodium are required to confer chloroquine resistance. From a report that spontaneous resistance to the drug can be found in roughly 1 parasite in 1020, he asserts that these are the odds of both mutations arising in a single organism, and uses them to make this sweeping assertion:

"On average, for humans to achieve a mutation like this by chance, we would need to wait a hundred million times ten million years. Since that is many times the age of the universe, it's reasonable to conclude the following: No mutation that is of the same complexity as chloroquine resistance in malaria arose by Darwinian evolution in the line leading to humans in the past ten million years."

Behe, incredibly, thinks he has determined the odds of a mutation "of the same complexity" occurring in the human line. He hasn't. What he has actually done is to determine the odds of these two exact mutations occurring simultaneously at precisely the same position in exactly the same gene in a single individual. He then leads his unsuspecting readers to believe that this spurious calculation is a hard and fast statistical barrier to the accumulation of enough variation to drive darwinian evolution."

Et, il démolit joyeusement l'argument... en égratignant la réputation de Behe au passage:
"It would be difficult to imagine a more breathtaking abuse of statistical genetics.

Behe obtains his probabilities by considering each mutation as an independent event, ruling out any role for cumulative selection, and requiring evolution to achieve an exact, predetermined result. Not only are each of these conditions unrealistic, but they do not apply even in the case of his chosen example. First, he overlooks the existence of chloroquine-resistant strains of malaria lacking one of the mutations he claims to be essential (at position 220). This matters, because it shows that there are several mutational routes to effective drug resistance. Second, and more importantly, Behe waves away evidence suggesting that chloroquine resistance may be the result of sequential, not simultaneous, mutations (Science 298, 74–75; 2002), boosted by the so-called ARMD (accelerated resistance to multiple drugs) phenotype, which is itself drug induced.

A mistake of this magnitude anywhere in a book on science is bad enough, but Behe has built his entire thesis on this error. Telling his readers that the production of so much as a single new protein-to-protein binding site is "beyond the edge of evolution", he proclaims darwinian evolution to be a hopeless failure. Apparently he has not followed recent studies exploring the evolution of hormone-receptor complexes by sequential mutations (Science 312, 97–101; 2006), the 'evolvability' of new functions in existing proteins — studies on serum paraxonase (PON1) traced the evolution of several new catalytic functions (Nature Genet. 37, 73–76; 2005) — or the modular evolution of cellular signalling circuitry (Annu. Rev. Biochem. 75, 655–680; 2006). Instead, he tells his readers that there is just one explanation that "encompasses the cellular foundation of life as a whole". That explanation, of course, is intelligent design."

Suit un relevé d'erreurs similaires tirées d'un autre livre de Behe ("Darwin's Balck Box"). Puis:
"No doubt creationists who long for a scientific champion will overlook the parts of this deeply flawed book that might trouble them, including Behe's admission that "common descent is true", and that our species shares a common ancestor with the chimpanzee. Instead, they will cling to Behe's mistaken calculations, and proclaim that the end of evolution is at hand. What this book actually demonstrates, however, is the intellectual desperation of the intelligent-design movement as it struggles to survive in the absence of even a shred of scientific data in its favour."

Jean-François

[Abognazar]

Voilà!

I had expected to be as irritated by Michael Behe’s second book as by his first. I had not expected to feel sorry for him. The first — “Darwin’s Black Box” (1996), which purported to make the scientific case for “intelligent design” — was enlivened by a spark of conviction, however misguided. The second is the book of a man who has given up. Trapped along a false path of his own rather unintelligent design, Behe has left himself no escape. Poster boy of creationists everywhere, he has cut himself adrift from the world of real science. And real science, in the shape of his own department of biological sciences at Lehigh University, has publicly disowned him, via a remarkable disclaimer on its Web site: “While we respect Prof. Behe’s right to express his views, they are his alone and are in no way endorsed by the department. It is our collective position that intelligent design has no basis in science, has not been tested experimentally and should not be regarded as scientific.” As the Chicago geneticist Jerry Coyne wrote recently, in a devastating review of Behe’s work in The New Republic, it would be hard to find a precedent.

For a while, Behe built a nice little career on being a maverick. His colleagues might have disowned him, but they didn’t receive flattering invitations to speak all over the country and to write for The New York Times. Behe’s name, and not theirs, crackled triumphantly around the memosphere. But things went wrong, especially at the famous 2005 trial where Judge John E. Jones III immortally summed up as “breathtaking inanity” the effort to introduce intelligent design into the school curriculum in Dover, Pa. After his humiliation in court, Behe — the star witness for the creationist side — might have wished to re-establish his scientific credentials and start over. Unfortunately, he had dug himself in too deep. He had to soldier on. “The Edge of Evolution” is the messy result, and it doesn’t make for attractive reading.

We now hear less about “irreducible complexity,” with good reason. In “Darwin’s Black Box,” Behe simply asserted without justification that particular biological structures (like the bacterial flagellum, the tiny propeller by which bacteria swim) needed all their parts to be in place before they would work, and therefore could not have evolved incrementally. This style of argument remains as unconvincing as when Darwin himself anticipated it. It commits the logical error of arguing by default. Two rival theories, A and B, are set up. Theory A explains loads of facts and is supported by mountains of evidence. Theory B has no supporting evidence, nor is any attempt made to find any. Now a single little fact is discovered, which A allegedly can’t explain. Without even asking whether B can explain it, the default conclusion is fallaciously drawn: B must be correct. Incidentally, further research usually reveals that A can explain the phenomenon after all: thus the biologist Kenneth R. Miller (a believing Christian who testified for the other side in the Dover trial) beautifully showed how the bacterial flagellar motor could evolve via known functional intermediates.

Behe correctly dissects the Darwinian theory into three parts: descent with modification, natural selection and mutation. Descent with modification gives him no problems, nor does natural selection. They are “trivial” and “modest” notions, respectively. Do his creationist fans know that Behe accepts as “trivial” the fact that we are African apes, cousins of monkeys, descended from fish?

The crucial passage in “The Edge of Evolution” is this: “By far the most critical aspect of Darwin’s multifaceted theory is the role of random mutation. Almost all of what is novel and important in Darwinian thought is concentrated in this third concept.”

What a bizarre thing to say! Leave aside the history: unacquainted with genetics, Darwin set no store by randomness. New variants might arise at random, or they might be acquired characteristics induced by food, for all Darwin knew. Far more important for Darwin was the nonrandom process whereby some survived but others perished. Natural selection is arguably the most momentous idea ever to occur to a human mind, because it — alone as far as we know — explains the elegant illusion of design that pervades the living kingdoms and explains, in passing, us. Whatever else it is, natural selection is not a “modest” idea, nor is descent with modification.

But let’s follow Behe down his solitary garden path and see where his overrating of random mutation leads him. He thinks there are not enough mutations to allow the full range of evolution we observe. There is an “edge,” beyond which God must step in to help. Selection of random mutation may explain the malarial parasite’s resistance to chloroquine, but only because such micro-organisms have huge populations and short life cycles. A fortiori, for Behe, evolution of large, complex creatures with smaller populations and longer generations will fail, starved of mutational raw materials.

If mutation, rather than selection, really limited evolutionary change, this should be true for artificial no less than natural selection. Domestic breeding relies upon exactly the same pool of mutational variation as natural selection. Now, if you sought an experimental test of Behe’s theory, what would you do? You’d take a wild species, say a wolf that hunts caribou by long pursuit, and apply selection experimentally to see if you could breed, say, a dogged little wolf that chivies rabbits underground: let’s call it a Jack Russell terrier. Or how about an adorable, fluffy pet wolf called, for the sake of argument, a Pekingese? Or a heavyset, thick-coated wolf, strong enough to carry a cask of brandy, that thrives in Alpine passes and might be named after one of them, the St. Bernard? Behe has to predict that you’d wait till hell freezes over, but the necessary mutations would not be forthcoming. Your wolves would stubbornly remain unchanged. Dogs are a mathematical impossibility.

Don’t evade the point by protesting that dog breeding is a form of intelligent design. It is (kind of), but Behe, having lost the argument over irreducible complexity, is now in his desperation making a completely different claim: that mutations are too rare to permit significant evolutionary change anyway. From Newfies to Yorkies, from Weimaraners to water spaniels, from Dalmatians to dachshunds, as I incredulously close this book I seem to hear mocking barks and deep, baying howls of derision from 500 breeds of dogs — every one descended from a timber wolf within a time frame so short as to seem, by geological standards, instantaneous.

If correct, Behe’s calculations would at a stroke confound generations of mathematical geneticists, who have repeatedly shown that evolutionary rates are not limited by mutation. Single-handedly, Behe is taking on Ronald Fisher, Sewall Wright, J. B. S. Haldane, Theodosius Dobzhansky, Richard Lewontin, John Maynard Smith and hundreds of their talented co-workers and intellectual descendants. Notwithstanding the inconvenient existence of dogs, cabbages and pouter pigeons, the entire corpus of mathematical genetics, from 1930 to today, is flat wrong. Michael Behe, the disowned biochemist of Lehigh University, is the only one who has done his sums right. You think?

The best way to find out is for Behe to submit a mathematical paper to The Journal of Theoretical Biology, say, or The American Naturalist, whose editors would send it to qualified referees. They might liken Behe’s error to the belief that you can’t win a game of cards unless you have a perfect hand. But, not to second-guess the referees, my point is that Behe, as is normal at the grotesquely ill-named Discovery Institute (a tax-free charity, would you believe?), where he is a senior fellow, has bypassed the peer-review procedure altogether, gone over the heads of the scientists he once aspired to number among his peers, and appealed directly to a public that — as he and his publisher know — is not qualified to rumble him.

[Jean-Francois]

Merci Abognazar.

De nombreux partisans de "théories" para-scientifiques (ou anti-scientifiques, comme les créationnistes) gagneraient à comprendre ce passage:

This style of argument remains as unconvincing as when Darwin himself anticipated it. It commits the logical error of arguing by default. Two rival theories, A and B, are set up. Theory A explains loads of facts and is supported by mountains of evidence. Theory B has no supporting evidence, nor is any attempt made to find any. Now a single little fact is discovered, which A allegedly can’t explain. Without even asking whether B can explain it, the default conclusion is fallaciously drawn: B must be correct

Surtout à cause de la suite:

Incidentally, further research usually reveals that A can explain the phenomenon after all

Jean-François

[curieux]

C'est normal qu'ils ne comprennent pas la difference entre théorie et hypothèse, il faut avoir vécu l'interieur d'un mouvement sectaire pour s'en convaincre.
Les créationnistes sont des extrémistes religieux qui partent du principe que les évolutionnistes s'accrochent à cette théorie parce que ça les arrange de ne pas croire en Dieu, sous-entendu que ça les arrange de ne pas avoir à se plier aux exigences requises par la spiritualité qui va avec. En clair ils se prennent pour l'élite, ce sont des élus de Dieu autoproclamés et donc, toute théorie qui va à l'encontre de leur foi est considérée comme une attaque frontale menée contre Dieu.
Au simple mot "évolution", ils se ferment comme des huitres comme d'autres se mettent à hurler à la vue d'une araignée ou d'une souris. Ils ont été ou se sont programmés eux-mêmes dans ce but, les seuls qui peuvent en sortir le feront à l'occasion d'un déclic quelconque qui amorcera le déroulement de l'écheveau de leurs idées fixes et qui aménera ce fait dans le champ de leur conscience.
Ce que certains en feront est une autre paire de manches.

[PKJ]

On peut aussi lire la réponse (hystérique, complètement à côté et ad hominem) de nos amis des Creation Ministries International:

http://www.creationontheweb.com/content/view/5213