Re: [BULK] - Re: Is evolution really the central theory for all of biology?

From: David C Campbell <amblema@bama.ua.edu>
Date: Mon Sep 19 2005 - 19:53:26 EDT

>David:
>Again, we're talking about evidence, not explanation. I did not present
convergence as a challenge to evolutionary explanations. I presented it
as a challenge to evolutionary evidence. Here is the general form of
the evolutionary claim:<
>1. Evolution claims similar designs as evidence for evolution.
>2. Similar designs that cannot be ascribed to common descent are
chalked up as examples of convergence.
>So evolution is having it both ways.

Convergence is expected under an evolutionary model and thus does not
pose a challenge to evolutionary evidence in the sense that it is
evidence for evolution-different organisms all evolving in the same
direction. (It can also be evidence for various other models besides
evolutionary models.) Convergence does pose a challenge to
interpretation of particular pieces of evidence-is it convergent or
homologous? However, as my previous post discussed, there are ways to
try to distinguish between convergence and similarities that are due to
common descent. One way I did not mention is in the many cases where
we have good evolutionary series in the fossil record and can see where
things come from.

>This is special pleading when the similar designs are claimed as
evidence for evolution (as in #1), but not when similar designs are
used as mere explanations (eg, "ah, these designs are similar because
they arose from a common ancestor").<

Not real sure what you mean.

----------------------------------------
Dr. David Campbell
425 Scientific Collections
University of Alabama, Box 870345
Tuscaloosa AL 35487
"James gave the huffle of a snail in
danger But no one heard him at all" A.
A. Milne
Received on Mon Sep 19 19:56:54 2005

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