Zeal For Truth

The Edge of Evolution, by Michael J. Behe
The Free Press, 2007
336 pages
Amazon.com link

More than a decade ago, in 1996, Michael Behe published Darwin’s Black Box. In it, Behe argued that Darwinian evolution is impossible: random mutation and natural selection cannot account for the intricate, irreducibly complex systems that make life possible. These systems–such as the way blood clots in mammals–are essential to life, and are made up of dozens–even hundreds–of parts. If even one part is missing, the system is useless and the creature dies. Behe argued that it is impossible for random mutations to build these irreducibly complex systems up piece by piece, step by step.

In 1996, Behe could offer no actual evidence for the impossibility of Darwinian evolution. All he offered was the idea of irreducible complexity. In the decade since Darwin’s Black Box, studies of mutation rates have furnished Behe with real-world data to support his earlier conclusions. In a new book published earlier this year, The Edge of Evolution, Behe uses scientific data to reveal what Darwinism can and cannot accomplish.

Definition of terms
Behe begins The Edge of Evolution by defining some terms. The word Darwinism encompasses three distinct ideas:

• common descent
• natural selection
• random mutation

Common descent is the idea that all living creatures have similar features that were inherited from a common ancestor. For example, dolphins and whales are descended from a common ancestor, as are dogs and cats, and even elephants and mice. “Common descent is what most people think of when they hear the word ‘evolution,’” says Behe. But common descent is not the full story.

Common descent tries to account only for the similarities between creatures. It merely says that certain shared features [e.g., complex cells with nuclei] were there from the beginning–the ancestor had them. But all by itself, it doesn’t try to explain how either the features or the ancestor got there in the first place, or why the descendants differ.

This brings us to Darwin. Darwin’s theory is that small random mutations, coupled with the mechanism of natural selection, can account for all the forms of life on earth. Natural selection means simply survival of the fittest: the creatures that have some natural advantage will produce more offspring, and thus pass on their natural advantages. Random mutations introduce small changes; natural selection weeds out the useless and harmful mutations; the beneficial mutations survive. Eventually, a lot of small changes add up to big changes–and thus life evolves into different forms and species.

So Darwinism means common descent by means of random mutation and natural selection. If Darwinism is true, all three ideas must be true, and they must be sufficient to account for all the different forms of life on Earth. Behe considers the DNA evidence in support of common descent to be overwhelming, and he does not dispute its truth. Random mutation and natural selection have been studied, and they “can modify life in important ways.” But not in ways sufficient to account for the origin of species, Behe concludes. For proof, he turns to some real-world studies of mutation rates in the malaria parasite.
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