I think that using comparative methods is one of the best ways to
uncover the possible steps that lead to the formation of biological
systems. In fact, comparative biochemistry is probably essential to
this work since there are no practical ways to model the evolution of
biochemical systems in the manner Behe describes. So, how can
comparative biochemistry be ignored in such a discussion when it is
absolutely essential?
I'm not just talking about similarities between say, serine proteases,
but between complex functional groups comprising things such as the immune
system. Do sharks have T-cells? Do reptiles have the same blood clotting
cascade as humans? Where and how are they different? I think that if one
analyzes such homogous systems in a diverse range of organisms then one
may find that some components were not always absolutely necessary and
thus might have evolved. It may even suggest part of the route taken.
The counter could be that each of these systems, though highly similar,
represent individual EA events (pace Howard Van Till), in each organism,
but that's pretty weak, IMO.
>[...]
>
>TI>The track record is not promising. Not too long ago Mike and Phil J.
>>wondered where the fossil intermediate forms for the whales were
>>to be found. As it turned out, they had been buried but now some
>>have been unearthed. Haven't heard much about this from either of
>>them since then
>
>Johnson's argument is not that the whale did came from a land mammal but
>that Darwinian `blind watchmaker' natural processes are inadequate to do
>it.
That's only half of the question posed.
Johnson actually has no statement to make about the origin of a whale
from a land mammal except to say the two can't be related by common
descent with gradual modification. The question about the fossils had
to do with whether intermediate forms could be found and whether there
were any gaps that could be filled in with fossils. This is the other
half of the question he posed. The answer seems to be yes. We may not
yet know the exact group to which the tree is rooted but some of the
intermediate positions seem to have been determined.
>Mike Behe (who accepts common ancestry) doubted that the Mesonychid
>was the ancestor of the whale. He was right! I posted recently an article
>from SCIENCE (Dennis Normile, "New Views of the Origins of
>Mammals," Science, August 7, 1998, p775).which reported that
>Thewissen, the discoverer of "the fossil intermediate forms for the whales"
>you refer to, has now ruled out Mesonychids as whale ancestors
That's been up for grabs at least since the molecular data was compared.
So Behe would now accept the possibility that they came from ungulates as
some fossil data and the molecular biological data would suggest? Come on,
if Behe (or you) thinks common descent happens then surely there must be
some intermediate ancestors between a land mammal and a whale and it should
be possible to identify the originating group. Unless of course, we're
talking about huge EA steps.
>TI>Well, Michael at least seems to have finally
>>accepted the more rational position of common descent.
>
>Behe has AFAIK *always* accepted common descent. He says so in
>Darwin's Black Box:
Oh, he does now. But if one once asked about the existence of potential
intermediates then I'd suggest that one wasn't entirely convinced about
common descent at the time.
>"For the record, I have no reason to doubt that the universe is the billions
>of years old that physicists say it is. Further, I find the idea of common
>descent (that all organisms share a common ancestor) fairly convincing,
>and have no particular reason to doubt it." (Behe M.J., "Darwin's Black
>Box," 1996, pp5-6)
This brings up another question of mine.
What exactly does "common descent" mean in the context of having whole
chunks of complex biochemical systems being suddenly hot-swapped into new
organisms? Clearly many components of organisms can't have gotten there
by common descent is that's the case.
>TI>It's still progressive creationism but at least that's a step in the
right
>>direction for establishing any sort of reasonable dialog on the subject.
>
>Not really. Darwinists rule out "progressive creationism" (and even theistic
>evolution for that matter). Julian Huxley, a co-founder of Neo-Darwinism,
>said that any "idea of God as the creator of organisms" was not even in
>"the sphere of rational discussion":
[...]
Why are you talking about atheistic Darwinists here? Many people in this
group have long attempted to help you understand that evolution need not
be exclusively viewed from the standpoint of philosophical naturalism.
For essentially all the times I've posted here, I've presented the
subject from the standpoint of methodological naturalism which certainly
can serve as a bridge between theists, agnostics and atheists in discussion
of natural phenomena and mechanisms. Here, at least, a progressive
creationist can piss and moan about whether natural mechanisms are
sufficient for the development of various organisms. Likewise,
theistic evolutionists or someone like Dawkins can bitch that current EA
hypotheses explain practically nothing about the patterns exhibited by
life. But at least they tend to agree about the same basic patterns they've
_observed_ in life. However, if a person can't accommodate common descent
and an ancient universe, then they're not even on the boat for these sorts
of discussions, IMO.
Regards,
Tim Ikeda
tikeda@sprintmail.hormel.com (despam address before use)