Analysis of Behe's Testimony, Part 1: Purpose and Function

I'm going to make a series of posts breaking down the testimony of Michael Behe in the Dover trial. The transcript for the direct examination and the first part of the cross examination are available now. Behe is really the only science witness the defense has in this case, with Dembski having been withdrawn earlier, and he is crucial to the defense's argument that ID is a genuine scientific theory. Unfortunately for them, Behe crashed and burned badly under cross examination. One inconsistency after another was picked up on and magnified, and you can see in the transcript how questions were used to set up the closing argument later. The first part of Behe's testimony I want to focus on is his argument for why ID is a positive theory, not merely a negative argument.

Before examining this argument, however, I want to point out something very important about Behe's position that must be kept in mind when examining these arguments. Behe does not reject evolution. He accepts common descent and he admits that there are complex biochemical systems the development of which are well understood by scientists and well explained as being the result of mutation and selection. He further admits that there is no need in those cases to infer or invoke an intelligent designer needing to intervene. During the cross examination, he admits that natural selection can account for many things at the biochemical level, including the hemoglobin chain and the antifreeze protein system in cold water fish. Both of those biochemical systems required multiple mutations and the coordination of different parts (different proteins) and genes in order to function effectively, and Behe accepts that mutation and selection can account for the development of those two systems, and many others, without the need for the intervention of an intelligent designer (though he appears to think that the explanation for hemoglobin isn't as detailed as for antifreeze proteins, he still accepts that it can be satisfactorily explained by mutation and selection). Indeed, I'm sure there is a whole range of biochemical systems that he would admit can be explained as a result of the well-understood and often documented process of gene duplication and recruitment of the resulting protein for a new function. This is very important, so keep it in mind as we examine his testimony.

In his testimony, and throughout his previous writings, Behe continually argues that there is a positive case for design: whenever you see a "purposeful arrangement of parts", that is evidence for intelligent design. This phrase popped up again and again in his testimony in various ways, but the bottom line for Behe is "that is exactly the basis for how we detect design, when we perceive the purposeful arrangement of parts." But here's the problem with this: what does "purposeful" mean in this context? How does one discern purpose? In this context, it can really only mean "functional" - a collection of parts that act together to perform a function. Indeed, Behe admits this in his testimony (p. 44 of cross):

I said that intelligent design is perceived as the purposeful arrangement of parts, yes. So when we not only see different parts, but we also see that they are ordered to perform some function, yes, that is how we perceived design.

So according to Behe, we know that a system was designed if it has a "purposeful arrangement of parts", and we know that an arrangement is "purposeful" if the parts are "ordered to perform some function." But wait a minute...when it comes to the antifreeze protein, a system that is obviously ordered (the development of the system involves a gene for a related protein, trypsinogen, being expanded, then duplicated, to produce a sequence of 41 tandem repeat segments) to perform some function (keeping the fish's blood from freezing at low temperatures), Behe does not infer design. In fact, we have multiple examples of antifreeze proteins in different species of fish, all derived independently of one another through different pathways, controlled by different genes and resulting in different sets of proteins, all of which Behe apparently accepts as being well explained by evolution without the need for the intervention of a designer. Yet these systems show the same trait - multiple parts order to perform a function - that he claims is a positive test for design.

So what does this inconsistency show? It confirms, once and for all, that ID is at base a "god of the gaps" explanation. He isn't really inferring design from the positive trait of having multiple parts ordered to perform a function, he only infers design when there is not yet a well understood and well documented evolutionary explanation for how a specific system with that trait developed through an evolutionary process. It is only in those instances where we don't yet have a thorough understanding of the pathway of development where Behe says, "A ha, God must have intervened to make it that way."

But as Michael Ruse likes to say, this type of argument is a science stopper. We can make that same inference or argument in science at all points leading up to having a problem solved or a phenomenon explained. At any point prior to that we could say, "Science cannot explain this, so God must have done it." Indeed, we did so for thousands of years by explaining thunderstorms, earthquakes and disease as evidence of the wrath of God and good crops as evidence of his pleasure with us. We now know better, and we know better because we didn't stop before we found a compelling theory to explain those things as being the result of natural processes.

Behe needs to be asked this question: If you now accept that the various antifreeze protein systems evolved without the intervention of a designer because we have well documented and reasoned explanations for how they developed, couldn't you have made the very same argument you make about the flagellum or blood clotting before we had those well documented explanations that you accept? And if that's the case, as it clearly is, and the inference to a designer from a lack of evolutionary explanation turned out to be false in that case, why should we think it's real in this case?