Re: [asa] historical versus experimental sciences

From: Tim <>
Date: Thu Aug 20 2009 - 21:48:42 EDT

Cameron Wybrow wrote:
> Note also Hebert's own rather pathetic explanation to try to get out
> of the
> consequences of his research: he postulates an evolutionary cleansing
> mechanism for which he has *absolutely no empirical evidence*, merely
> because without such a mechanism he does not see how he can fight off
> "creationist" conclusions. Sadly, that's the neo-Darwinian way of doing
> science. When the facts are against you, postulate undocumented
> mechanisms,
> forces, factors, etc. Do *anything* but admit that the evidence may
> be more
> in favour of intelligent design than of accidental mutations and
> fortuitous
> selections. In neo-Darwinism, empiricism goes out the window in
> favour of
> maintaining *a priori* commitments to chance and necessity. This is why
> neo-Darwinism is an embarrassment to science. It does not meet the
> minimum
> requirements of intellectual honesty, which dictate that when opponents
> score a point, it should be granted to them.

Actually, there are many *known* mechanisms behind the accumulation of
genetic changes and these often happen together. The question is which
mechanisms have the strongest influence. This matters because different
mechanisms produce different phenomena and this potentially allows one
to distinguish between mechanisms. From those models, one can go back
and examine whether those influences are consistent in similar
situations. One can also work deeper, even to the core biochemistry, to
see what makes mitochondria exceptional in this regard. What Herbert
found was that neutral drift was likely not a dominant mechanism in
reducing within-species diversity for the gene encoding cyt-c oxidase.
*That* observation didn't fit with empirical results. Other researchers
have confirmed this and presented evidence supporting models with more
frequent sweeps. In contrast, neutral theory is more in accord when they
examine nuclear genes. This points to several possible mechanisms
operating with the mitochondrion, a few of which might be amenable to

Interestingly, the results do confirm a strong temporal correlation with
between-species diversity and the proposed time since the populations
split. That's certainly an unexpected result for those proposing a
separate creation model for species.

Cameron, I personally don't consider meteorology an embarrassment to
science because meteorologists don't discard "*a priori* commitments to
chance and necessity" when they can't predict the weather several weeks
in advance. There are any number of phenomena found in all branches of
the physical sciences for which we don't have refined explanations --
Some hints in many cases, but still with details undetermined. Does it
raise your ire when scientists persist in investigating mechanisms of
"chance and necessity" in other fields? At least in my work, I always
work to exhaust natural mechanisms first. Further, if one finds that
evolutionary mechanisms are too flexible, how does adding "intelligent
design" to the explanatory mix help? And why is the history of life
afflicted with such metaphysical uneasiness and not, say, embryological
development, cancer or oil viscosity breakdown in engines?

T. Ikeda

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Received on Thu Aug 20 21:49:51 2009

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