Mark24<< It is not implicit in the definition of IC, that IC cannot evolve. >>
Warren<< Correct. That's why no ID theorist makes the claim that IC systems can't evolve.>>
Mark24<< Thornhill & Ussery describe four possible pathways for IC evolution & they define it in the same way as Behe. Creationists claim, without evidence, that IC cannot evolve, they're just a little weak on supporting evidence, that's all.>>
Warren<< Thornhill & Ussery describe four possible evolutionary pathways. Two direct pathways and two indirect pathways. Their paper shows that the two direct evolutionary pathways can't produce IC systems. It is these two direct pathways that ID theorists claim can't produce IC systems. They do not assert that evolution of IC systems via indrect means is impossible. The two pathways ruled out by Thornhill & Ussery happen to be the pathways we have the most evidence for. The other two pathways rely on pure chance. Now no ID theorist is going to claim that it's absolutely impossible for an IC system to arise by chance, however, Darwinian theory is supposedly more than merely invoking chance. Dawkins says:
"...To this day, and in quarters where they should know better, Darwinism is widely regarded as a theory of 'chance'. It is grindingly, creakingly, crashingly obvious that, if Darwinism were really a theory of chance, it couldn't work. You don't need to be a mathematician or physicist to calculate that an eye or a haemoglobin molecule would take from here to infinity to self-assemble by sheer higgledy-piggledy luck."
But the two evolutionary pathways that Thornhill & Ussery describe as capable of producing IC systems amount to nothing more than chance, luck, coincidence etc. One of these is co-option. Mike Gene notes :
"Co-option is the most commonly cited circuitous means to generate an IC system. Bur this really isn't Darwinian evolution (i.e. step by step changes captured by selection.) It is essentially a return to raw coincidence to account for apparent design. The brilliance of Darwin was to minimize the role of chance in apparent design. But once we turn to the co-option explanation, we leave this explanatory appeal behind, as chance reasserts itself into a place of prominence.... and just as it was not convincing in pre-Darwinian days, it is not convincing today."
Despite all the expressed incredulity that is so common among Behe's critics, he has indeed contributed to science by forcing scientists like Thornhill & Ussery to classify routes of evolution thus showing that 50% of the possible routes can't generate IC machines. This is progress. Without Behe, for example, many would probably still think that classic evidence of random mutation & natural selection allows us to think the bacterial flagellum evolved by the same mechanism.>>
[This message has been edited by Warren, 07-30-2003]
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