Re: Is evolution really the central theory for all of biology?

From: Terry M. Gray <grayt@lamar.colostate.edu>
Date: Mon Sep 19 2005 - 16:55:44 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. 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").
>
> --Cornelius

Cornelius,

It's not special pleading if there are real examples of convergence,
i.e. it's part of what we expect in the complex biological world and
there are ways to distinguish between them. The main way to
distinguish them is whether or not there are other arguments/
evidences for common ancestry. If not, convergence; if so, most
likely, common ancestry. I, for one, wouldn't rule out convergence
among related lineages, but then it becomes very difficult to tell
without nearly complete molecular pedigree data.

TG

________________
Terry M. Gray, Ph.D.
Computer Support Scientist
Chemistry Department
Colorado State University
Fort Collins, CO 80523
(o) 970-491-7003 (f) 970-491-1801
Received on Mon Sep 19 16:57:27 2005

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