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At a very early stage of the campaign for the 2008 presidential election, a television event was staged at which a domineering host insisted that the Republican candidates answer “yes” or “no” to his question, “Do you believe in evolution?” It was a trick question designed to embarrass, because evolution is not a single, precisely defined concept, but a set of related concepts, some of which are much better supported than others. The candidates should have demanded a precise definition before they would answer, but the format did not permit that option.
If the question had referred only to the evolutionary process by which disease-causing viruses become resistant to antiviral drugs, then all of the candidates, and all of the voters, would have answered “yes.” If the question had been whether all living organisms share a common ancestor, then the responses might have been fairly evenly divided. If the question had been, “Do you agree that the development of life from the first living cell up to and including humans was governed by Darwin’s mechanism of random mutation with natural selection, so that there was no need or room for a creator at any point?”, there might have been more answering “no” than “yes.”
By demanding a yes or no answer to his oversimplified question, “Do you believe in evolution?”, the host was refusing to allow the candidates to make sense of his question before answering it. That kind of oversimplification belongs to the realm of partisan politics or comedy, not science.
But sadly, some widely used biology textbooks also mislead rather than enlighten, when they explain “evolution.” A common story from the Darwinist literature illustrates why it is so important to distinguish between the things the Darwinian mechanism can do and the things it can’t do. A mutation that first occurred in humans thousands of years ago creates a “sickle cell” gene, which causes a deformation in a person’s blood cells. When a person inherits the mutant gene from both parents, he develops a terrible sickle-cell disease that causes disability and early death.
Biologists wondered why the mutant gene persisted in the species for so long, instead of being eliminated by natural selection. The modern form of Darwin’s theory provides a good answer: Often a person inherits the mutation from only one parent, and in this case he does not get the full disease. In fact, the mutation confers some protection from the ravages of malaria, which kills enormous numbers of people, especially in early childhood, in some areas of the world, including Africa.
Because malaria is so deadly, persons with the sickle-cell mutation have an enhanced likelihood of surviving to adulthood in malaria-prone areas, and this nicely accounts for the persistence of what is otherwise a highly disadvantageous mutation. For the descendants of Africans in America, however, the anti-malarial protection is unimportant, and the mutation is only a terrible killer with no benefit. In time, natural selection will eliminate it.
The Truth About Mutations
That is the sickle-cell story, a Darwinian favorite.
The story illustrates a general truth about mutations, which tends to discredit the Darwinian assumption that mutations, with natural selection, can be used to build new complex organisms, like people, from much simpler ancestors. Actually, mutations do not build adaptive complexity, but degrade it.
When some deadly condition like a parasite or poison is pervasive in an environment, a mutation may occasionally tweak an organism’s biochemistry in such a way that it confers a benefit in that specific environment. Even in such cases, though, the mutation is not providing some new organ, and a negative effect on fitness will appear if the environment changes to remove the harmful influence. The mutation is not preparing the organism to become something different, and better.
My colleague Michael Behe’s new book, The Edge of Evolution, uses the long history of the war between humans and the malarial parasite to show what the Darwinian mechanism can and cannot do. To offer a taste of what he writes, here he uses an architectural metaphor:
The major architectural features of life—molecular machinery, cells, genetic circuitry, and probably more—are purposely designed. But the architectural constraints leave spandrels that can be filled with Darwinian adaptations.
Behe’s treatment of the subject is especially valuable, because he focuses attention upon the subject of mutations, both the most important element in the neo-Darwinian theory, and the most dubious.
Of course, Richard Dawkins attacked the book and its author when he reviewed it in the New York Times. The review was a literary drive-by shooting. After contemptuous remarks of a personal nature, Dawkins ignored all Behe’s data about what mutations have actually been shown to do, merely commenting that favorable mutations must be sufficiently plentiful to allow us to obtain a great variety of dog breeds. Dog breeders are not dependent upon mutations, however, which would damage their animals. Breeders bring out the variety that was latent in the genome from which they started.
The truth about mutations is sufficiently well known now to scientists around the world, that the day will eventually come when it can no longer be excluded from mainstream scientific discourse. It is often said that science is a self-correcting enterprise. I have faith that this claim is true—in the very long run.