Bilbo Defends' Behe's Irreducible Complexity

[swamidass (S. Joshua Swamidass)]

The two places I quote Behe’s changing definition:

@swamidass

the IC1 definition…

a single system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.

@swamidass

So what is the next definition of IC, which I will call IC2? In 2000 Behe writes a different definition, that he carries forward to this day in the Edge of Evolution .

An irreducibly complex evolutionary pathway is one that contains one or more unselected steps (that is, one or more necessary-but-unselected mutations). The degree of irreducible complexity is the number of unselected steps in the pathway.
http://www.discovery.org/a/442

Now this definition suffers greatly compared to IC1, because it is not longer objective and directly measureable. Instead, we need to understand something of the evolutionary pathway, which is not directly observable.

Still, for the IC2, most knowledgeable scientists agree that IC2 systems exist in nature too. Similar to IC1 systems, we are convinced that evolution can evolve IC2 systems also. Embedded in this definition is an important straw man. He writes “one or more unselected steps.” Here, into the IC2 definition is being smuggled a strict enforcement of “Darwinian” evolution. Now, anyone following biology at a basic level of competence knows that strict-Darwinian evolution was falsified a long time ago, in the 1970s. We now know that a large proportion of changes are near neutral or even slightly deleterious in the short term. So this dominant pathway of change is intrinsically ruled out by Behe’s definition.

Note, that the second definition pops up in 2000. Was there yet another definition here?

@Dan_Eastwood

@Bilbo IIRC, the definition was changed in Behe and Snoke (2004). That might be a good place to start.