William Dembski and the Negative Rhetoric of Intelligent Design Theory

Bill Dembski is one of the leading proponents of "intelligent design theory" as an alternative to Darwinian science. At his weblog, he has recently posted a Foreword to a forthcoming book. He boldly declares: "Evolutionary theory, in its grand macroevolutionary Darwinian form, flies in the face of the scientific method and should not be taught except as a discredited speculative hypothesis that properly belongs to nature religions and mystery cults and not to science."

To support this conclusion, he employs the same rhetorical strategy of negative argumentation that runs through all of the intelligent design reasoning. He concedes that there is plenty of evidence for "small-scale microevolution" and "a gradual progression of living forms." But he denies that the Darwinians have shown the "macroevolution" of novel species from ancestral species through chance mutations and natural selection. In one of his comments, he speaks of "the utter absence of a detailed account of how the Darwinian mechanism can build biological complexity."

Try this exercise. Go through this statement and replace "Darwinism" and "evolutionary theory" with "intelligent design theory." You will see that Dembski's negative argumentation depends on demanding a level of proof and evidence that has never been met by "intelligent design theory." We could easily speak of "the utter absence of a detailed account of how the intelligent-design mechanism can build biological complexity."

For example, one of the favorite examples of biological complexity for the IDers is the bacterial flagellum. They rightly point out that Darwinists have not yet offered a step-by-step account of the evolutionary pathway by which bacterial flagella have arisen by random mutation and natural selection. But the Darwinians could respond by pointing out that the IDers have not yet offered a step-by-step account of the precise pathway by which the Intelligent Designer did this. Exactly when, where, and how did the Intelligent Designer create flagella and attach them to bacteria? The IDers have no answer to that question. But their rhetorical strategy depends on negative argumentation in which they criticize the Darwinians for failing to provide exact step-by-step explanations for the emergence of biological complexity, while refusing to provide their own explanations.

As long as they put the Darwinians on the defensive, they win the debate. But if Darwinians were to employ the same rhetorical strategy, they could declare: "Intelligent design theory, in its grand Creationist form, flies in the face of the scientific method and should not be taught except as a discredited speculative hypothesis that properly belongs to nature religions and mystery cults and not to science."

But what would be accomplished by such sophistical invective? Wouldn't it be more sensible and intellectually productive for both sides in this debate to challenge one another to come up with the best positive explanations for biological complexity? If the IDers have a precise, testable explanation of exactly when, where, and how the Intelligent Designer created the bacterial flagellum, let them offer it, so that scientists can go into their laboratories to test it. If the Darwinians have a better explanation, let them offer it for testing.