In his review of Darwin’s Black Box for Nature, Jerry Coyne, professor of evolutionary biology at the University of Chicago, explains why he also thinks intelligent design is unfalsifiable.
If one accepts Behe’s idea that both evolution and creation can operate together, and that the Designer’s goals are unfathomable, then one confronts an airtight theory that can’t be proved wrong. I can imagine evidence that would falsify evolution (a hominid fossil in the Precambrian would do nicely), but none that could falsify Behe’s composite theory. Even if, after immense effort, we are able to understand the evolution of a complex biochemical pathway, Behe could simply claim that evidence for design resides in the other unexplained pathways. Because we will never explain everything, there will always be evidence for design. This regressive ad hoc creationism may seem clever, but it is certainly not science. (Coyne 1996)Coyne’s conclusion that design is unfalsifiable, however, seems to be at odds with the arguments of other reviewers of my book. Clearly, Russell Doolittle (Doolittle 1997), Kenneth Miller (Miller 1999), and others have advanced scientific arguments aimed at falsifying ID. (See my articles on blood clotting and the “acid test” on this web site.) If the results with knock-out mice (Bugge et al. 1996) had been as Doolittle first thought, or if Barry Hall’s work (Hall 1999) had indeed shown what Miller implied, then they correctly believed my claims about irreducible complexity would have suffered quite a blow. And since my claim for intelligent design requires that no unintelligent process be sufficient to produce such irreducibly complex systems, then the plausibility of ID would suffer enormously. Other scientists, including those on the National Academy of Science’s Steering Committee on Science and Creationism, in commenting on my book have also pointed to physical evidence (such as the similar structures of hemoglobin and myoglobin) which they think shows that irreducibly complex biochemical systems can be produced by natural selection: “However, structures and processes that are claimed to be ‘irreducibly’ complex typically are not on closer inspection.” (National Academy of Sciences 1999, p. 22)
Now, one can’t have it both ways. One can’t say both that ID is unfalsifiable (or untestable) and that there is evidence against it. Either it is unfalsifiable and floats serenely beyond experimental reproach, or it can be criticized on the basis of our observations and is therefore testable. The fact that critical reviewers advance scientific arguments against ID (whether successfully or not) shows that intelligent design is indeed falsifiable.
In fact, my argument for intelligent design is open to direct experimental rebuttal. Here is a thought experiment that makes the point clear. In Darwin’s Black Box (Behe 1996) I claimed that the bacterial flagellum was irreducibly complex and so required deliberate intelligent design. The flip side of this claim is that the flagellum can’t be produced by natural selection acting on random mutation, or any other unintelligent process. To falsify such a claim, a scientist could go into the laboratory, place a bacterial species lacking a flagellum under some selective pressure (for mobility, say), grow it for ten thousand generations, and see if a flagellum—or any equally complex system—was produced. If that happened, my claims would be neatly disproven.
Michael Behe[1]Cordially,