That sound you hear ...

... is the scraping of goalposts being moved:

While you’re at PubMed, try searching for “bacterial flagella secretion.” One of the resulting papers, by SI Aizawa (2001), reports that some nasty bacteria possess a molecular pump, called a type III secretion system, or TTSS, that injects toxins across cell membranes.

Much to Dr. Behe’s distress, the TTSS is a subset of the bacterial flagellum. That’s right, a part of the supposedly irreducible bacterial “outboard motor” has a biological function!

When I asked Dr. Behe about this at lunch he got a bit testy, but acknowledged that the claim is correct (I have witnesses). He added that the bacterial flagellum is still irreducibly complex in the sense that the subset does not function as a flagellum.

His response might seem like a minor concession, but is very significant. The old meaning of irreducible complexity was, “It doesn’t have any function when a part is removed.” Evidently, the new meaning of irreducible complexity is “It doesn’t have the same function when a part is removed.”

And so it goes. (Not surprisingly, via Pharyngula.)