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Sean Carroll Fails to Scale The Edge of Evolution (Part III): Is Carroll Scared of Approaching the Edge of Evolution?

Casey Luskin

[Editor’s Note: This is Part 3 of a 4-part response. The full response can be read here.]

edgeofev.jpgIn Part I of this series, I discussed how Sean Carroll’s review of Michael Behe’s new book, The Edge of Evolution: The Search for the Limits of Darwinism, misrepresents and oversimplifies Behe’s arguments. In Part II, I discussed the fact that one of Carroll’s citations actually confirms Behe’s argument that there is an edge to evolution, and that evolution tends to not proceed forward when additional mutations decrease functionality. In this installment, I will discuss how many of Carroll’s cited papers report types of evolution that Behe readily concedes can occur, and are unimpressive examples within the “edge” of evolution.

It’s Easier to Tear Down Walls than to Build Them
To demonstrate the power of evolution, Carroll cites the evolution of toxins. But Behe provides a ready discussion regarding the evolvability of destructive proteins because they entail merely evolving the ability to break things in the cell–a relatively simple task:

Foreign proteins injected into a cell by an invading virus or bacterium make up a different category. The foreign proteins of pathogens almost always are intended to cripple a cell in any way possible. Since there are so many ways to break a machine than to improve it, this is the kind of task at which Darwinism excels. Like throwing a wad of chewing gum into a finely tuned machine, it’s relatively easy to clog a system–much easier than making the system in the first place. Destructive protein binding is much easier to achieve by chance.

(Michael J. Behe, The Edge of Evolution: The Search for the Limits of Darwinism, pg. 149 (Free Press, 2007).)

It seems like Behe has a ready rejoinder to Carroll’s mention of the evolution of toxins.

Carroll’s Sickening Citations
In another incredibly misplaced example, Carroll cites the evolution of malarial resistance to drugs as a rebuttal to Behe. Yet Behe spends multiple chapters discussing the evolution of resistance to malaria and how it generally entails unimpressive genetic changes that, in actually, demonstrate that there is a limit to evolutionary change

Finally, as I discussed in part II, Carroll also cites antibiotic resistance by referencing a paper that agrees with Behe’s finding that there is an edge to the creative power of Darwinian evolution. In fact, Behe finds that bacterial mechanisms of antibiotic resistance present a challenge to natural selection that pales in comparison to the challenge posed by true complexity of the cell:

Where is it reasonable to draw the edge of evolution? … One the one side … several mutations can sequentially add to each other to improve an organism’s chance of survival. An example is the breaking of the regulatory controls of fetal hemoglobin to help alleviate sickle cell disease. … On the other side are the examples of what random mutation and natural selection clearly cannot do. … The structural elegance of systems such as the cilium, the functional sophistication of the pathways that construct them, and then the total lack of serious Darwinian explanations all point insistently to the same conclusion: They are far past the edge of evolution. Such coherent, complex, cellular systems did not arise by random mutation and natural selection, any more than the Hoover Dam was built by the random accumulation of twigs, leaves, and mud.

(Michael Behe, The Edge of Evolution: The Search for the Limits of Darwinism, pg. 111-112, (Free Press, 2007).)

Carroll simply isn’t engaging Behe’s arguments. He cites papers that discuss the evolution of biological functions that Behe already acknowledges are within the “edge” of what Darwinian evolution can produce. As discussed in the next post, Carroll’s only attempts to approach Behe’s edge of evolution fall far short.