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by Darel Rex Finley
In
"Darwin v. Intelligent Design (Again)," (also here) Allen Orr argues against Michael Behe's thesis of irreducible complexity, as presented in Behe's book Darwin's Black Box.
Much of the article is spent in a condescending criticism of Behe as someone who ought to be some sort of Bible-thumping fundamentalist instead of a credentialed biochemist, but nearly halfway through the article Orr gets to the point that matters:
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Behe's colossal mistake is that . . . he concludes that no Darwinian solution remains. But one does. It is this: An irreducibly complex system can be built gradually by adding parts that, while initially just advantageous, become — because of later changes — essential. The logic is very simple. Some part (A) initially does some job (and not very well, perhaps). Another part (B) later gets added because it helps A. This new part isn't essential, it merely improves things. But later on, A (or something else) may change in such a way that B now becomes indispensable. This process continues as further parts get folded into the system. And at the end of the day, many parts may all be required.
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Having said this, Orr immediately regresses to a late-1800's level of biology:
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The transformation of air bladders into lungs that allowed animals to breathe atmospheric oxygen was initially just advantageous: such beasts could explore open niches — like dry land — that were unavailable to their lung-less peers. But as evolution built on this adaptation (modifying limbs for walking, for instance), we grew thoroughly terrestrial and lungs, consequently, are no longer luxuries — they are essential.
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One of the major points of Behe's book is that we can imagine air bladders evolving into lungs all we want, if we ignore the biochemical machines that make these things possible. Behe spent an entire chapter of Darwin's Black Box pointing out that leading scientific journals and textbooks are virtually devoid of any attempt to apply Orr's "Part A, Part B" scenario to real biochemical systems.
What's worse, Orr's non-biochemical example of bladders-to-lungs is an example of "Part A, Part B" only if one presumes evolution to be true in the first place. Orr is repeating a favorite practice of evolutionists: Citing the claims of the theory as if they were facts that prove the theory true.
"Part A, Part B" is not entirely unreasonable when described in isolation, but in the empirical world it suffers from the same problem as Gould and Eldredge's "punctuated equilibrium": Is it reasonable to apply a speculative scenario so broadly, as an automatic explanation for so many evolutionary counter-examples? Behe made the point on page 40 of Darwin's Black Box:
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Even if a system is irreducibly complex (and thus cannot have been produced directly), however, one can not definitively rule out the possibility of an indirect, circuitous route. As the complexity of an interacting system increases, though, the likelihood of such an indirect route drops precipitously. And as the number of unexplained, irreducibly complex biological systems increases, our confidence that Darwin's criterion of failure has been met skyrockets toward the maximum that science allows.
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The "maximum that science allows" means that Behe is keeping an open mind that detailed "Part A, Part B" explanations of biochemical systems may yet be discovered. But until they are, Orr's answer will be satisfying only to those who harbor an a priori rejection of intelligent design.
Other less-important comments on Orr's article:
 Orr cites the irreducible complexity of computer programs as proof that such systems can arise gradually. He fails to mention that computer programs are created by intelligent designers, not by natural selection acting on random mutation.
Orr cites the similarity of myoglobin to hemoglobin as another example, and accuses Behe of running to "safer turf" and leaving these similarities unanswered. Here, Orr is beginning to miss the point. The question isn't how similar two proteins are, but how either of them could have been constructed by natural selection acting on random mutations. If hemoglobin can be turned into myoglobin by making certain changes, that still leaves the mechanism of change unspecified.
Orr says that since the irreducible complexity of the heart didn't topple Darwinism, why should irreducible complexity at the molecular level do it either? The answer is: Why not? If the heart is really irreducibly complex, then it didn't topple Darwinism because Darwinists simply ignored it. Perhaps they will ignore molecular problems as well.
Orr faults Behe for suggesting "that biochemical examples are best because they're simpler and thus clearer" when biochemistry is actually very complicated. What Behe probably meant was molecular machines do not have black boxes within them to complicate the issue or render the answer mysterious.
Orr points to Behe's mousetrap and says that since we don't need to worry about the molecular composition of the mousetrap, so we don't need to worry about the molecular composition of the heart! This is silly — the heart is made of cells filled with micromachinery which evolutionists need to explain; a mousetrap is not. Behe uses the mousetrap as an analogy to the micromachinery of the cell.
Orr tries to make Behe look self-contradictory by blurring the distinction between common ancestry and macroevolution. But the difference is clear: Common ancestry means that one species changed into another; macroevolution (as Behe uses the term) is the claim that such changes were accomplished by natural selection acting on random mutation, rather than directed change by intelligent intervention.
Orr extensively criticizes Behe's "primal cell" paragraph (pp. 227-228), without acknowledging that Behe was not claiming to believe in a "primal cell" nor encouraging his readers to do so. He was merely using a simple hypothetical to make a point about the age of a design. Behe's point would apply equally well to a more empirically tenable scenario of periodic modification.
Orr repeats the tired claim that questioning evolution is like questioning gravity. There is no basis for this comparison.
Orr concludes:
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So when the Christian Right tries to tell you that evolutionists instinctively circle the wagons whenever anyone dares question the Darwinian status quo, you should ask yourself why Wright and Kimura got through, but Behe not. The answer is, I think, straightforward: Wright and Kimura knew what they were talking about.
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The answer is even more straightforward than that: Wright's and Kimura's works do not challenge the claim that all of life's complexity was designed by natural selection acting on random mutation. Behe's does.
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