<<Suppose a primordial structure provided an early selective advantage because
it increased the surface area of the cell and facilitated nutrient uptake?
This primordial structure would not need all of the components of a cilia
which seems to take care of the problem of irreducible complexity of cilia.
The point of this exercise is that the concept of irreducible complexity
has an a priori constraint of functional similarity between
proto-structures and "final" structures that I am not sure is reasonable.
In other words, it seems that by irreducible complexity, Behe
means that complex structures are FUNCTIONALLY irreducible. If we ignore
the functional constraint, is Behe's view of evolution still reasonable?>>
Yes. Behe discusses this point, and on pg. 40 says: "Even if a system is
irreducibly complex (and thus cannot have been produced directly), however,
one cannot definitively rule out the possibility of an indirect, circuitous
route. As the complexity of an interacting system increases, though, the
likeliehood of such an indirect route drops precipitously. And as the number
of unexplained, irreducibly complex biological systems increases, our
confidence that Darwin's criterion of failure has been met skyrockets toward
the maximum that science allows....Such an appeal to brute luck can never be
refuted. Yet it is an empty argument....Luck is metaphysical speculation;
scientific explanations invoke causes."
Sure, one can imagine (and I use that term advisedly) virtually anything. But
at some point it becomes so fabulistic (e.g., Glenn Morton's motorcycle) that
it strains credulity past the breaking point. This is why Phil Johnson dubs
much of evolutionary thinking "just-so stories." As in the Kipling fable of
how the leopard got its spots, one can "imagine" anything for an explanation.
But scientific evidence is another matter.
The imaginary tool I find evolutionists waving like a magic wand is the one
Steve uses above, viz.: "Suppose a primordial structure provided an early
selective advantage..."
One can ALWAYS suppose some "selective advantage" to show that Darwinism
works. And then you can say Darwinism works BECAUSE OF such "selective
advantage." That is tautology raising its ugly head because, when it comes to
the philosophy of evolution, tautology has a selective advantage of its
own--it gets you out of any problem!
Jim