Honestly, there is a rhetorical genius to Behe’s argument, and I think he deserves an immense amount of credit for this.
Rhetorically, his approach shifts the burden of proof to the evolutionary scientist.
He expresses incredulity at the idea that “darwinism” could produce a complex structure, and asks for an account.
He is upfront about not considering how design works, which is actually reasonable if we are talking about divine design.
Whatever is offered, he asks for more detail and more evidence, and usually objects to anything but positive selection as an explanation, thereby constraining the explanations to a strict darwinistic account.
Rhetorically, this is brilliant for several reasons. First, his request for an account is usually met because it seems reasonable and evolutionary science often does give a partial account. Evolutionary science usually offers accounts that are:
- Plausible, given a sophisticated understanding of how biology works.
- Partial, not seeking to be total or sufficient.
- Complex, appealing to several mechanisms, not just positive selection.
Behe means something different when he asks for an account. He wants an account that is,
- Demonstrated, often by ruling out other alternate pathways at every step.
- Complete, in that we can drill down to arbitrary detail with out losing certainty.
- Simple, relying only or primarily on positive selection and easy for a crowd of non-specialists to understand.
Behe now has a great rejoinder every time something plausible rather than demonstrated, partial rather than complete, or complex either than simple is used in the account provided by his interlocure.
The thing is, evolutionary science (really any science) does not produce “demonstrated+complete+simple” explanations of anything. The rhetorical genius, however, is that most people think that science does produce explanations like this, so Behe’s rejoinders seem imminently reasonable. Of course, if he is asked to give a detailed account, he does not, but he returns to his chorus “purposeful arrangement of parts.” When pressed further, as he did in Texas, he rightly notes (indirectly) that God’s design is inscrutable.
I understand (and agree with) the scientific critique of this approach to reasoning, but do not miss the point. Behe’s pattern here is pure rhetorical genius, and it is not surprising that it convinced masses. With Darwin Devolves, there is a similar rhetorical genius, but it works in a different way.
Any how, that is why I focused on common ground, and did not give a step-by-step account of flagellum in public (but I did privately to Tour regarding his question). He agrees that neutral theory provides strong evidence for common descent (contra @BenKissling) and never explains it. I explained it, and he agreed with my explanation, but somehow felt compelled to dispute it? Any how, that approach granted legitimacy to a valid scientific argument with which he agrees but rarely explains.