Hi Cliff,
I wrote:
>I'm still trying to find the evidence that mutations and natural selection
>were indeed the mechanisms behind macroevolution. There seems to be a large
>consensus that this was the case, but where's the evidence? I understand
how
>various metaphysical views can incorporate natural selection and transform
it
>into the driving mechanism, but apart from those metaphysics, where is the
>persuasive appeal of such a belief?
You replied:
>When you eliminate the impossible explanations, what remains, however
>unlikely, is the truth. (I wish I could remember the exact wording of that).
>If you think divine intervention is out, and gradualism is out (as a
>significant creative mechanism), and if you believe in naturalistic
explanation,
>then macroevolution through RM&NS is all that's left.
I understand that RM&NS are invoked as a consequence of excluding
other explanations. In fact, I recently posted a short review of E.G. Leigh's
article from TREE. He explains:
"The primary problem with the synthesis is that its makers
established natural selection as the director of adaptive
evolution by eliminating competing explanations, not
by providing evidence that natural selection among
'random' mutations could, or did, account for observed
adaptation. Mayr remarked, 'As these non-Darwinian
explanations were refuted during the synthesis‰¥Ï.natural
selection automatically became the universal explanation
of evolutionary change (together with chance factors).'"
To his credit, Leigh not only recognizes this is a *problem*,
but also that it is the burden of those who propose RM&NS
as the drivers of evolution to come up with the evidence for
such a belief:
"However, the failure to provide clinching evidence
gives antidarwinians no reason to substitute natural
selection for God in their view of the world. Neither
have antidarwinians any vested interest in a mechanistic
explanation of the origin and evolution of life; if we
want them to accept one, it will have to be convincing."
Unfortunately, while Leigh attempts to find fingerprints
for the crucial role of natural selection, he does so by
simply excluding, a priori, intelligent intervention/selection.
Obviously, if we exclude intelligent intervention for
metaphysical reasons, we are left only with RM&NS.
But some of us remain open to *both* possible explanations
and it thus becomes quite disappointing to realize the
large consensus about RM&NS is not because of the
evidence.
Cliff:
>Macroevolution need not occur in the simple way gradual evolution occurs.
>Parabiosis or Siamese-twinning, genomic integration of symbionts, radical
>loss of parts--all these are perfectly attainable through RM&NS.
I can think of no reason to disagree, but then what is merely "attainable" is
not sufficient. Evolution is a question of history and not philosophy.
If we are trying to erect a philosophical explanation, I can appreciate
the importance of what is possible. But what is merely possible is
quite insufficient when trying to come up with a historical explanation.
>As to direct evidence, one must either wait for a time machine, or wait for
>the unique evolutionary mechanisms of half a billion years ago to start
functioning
>anew.
I am not asking for direct evidence as I do not expect such a thing. Indirect
evidence is just fine. What indirect evidence indicates that a major
evolutionary innovation was indeed the product of RM&NS?
>I don't think those mechanisms are going to work in the present
>well-evolved ecosystem; only in a more benign primitive environment
>could such bizarre experiments gain a foothold.
I understand the philosophy. But where is the evidence behind these
beliefs about history?
Mike
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