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

From: Cornelius Hunter <ghunter2099@sbcglobal.net>
Date: Mon Sep 19 2005 - 20:48:37 EDT

Terry, Douglas and David:

Terry and Douglas :

Evolution can explain:

1. Dramatic differences in otherwise highly similar species.
2. Dramatic similarities in otherwise distant species.

In this "homology vs analogy" space, it is not clear what real limits there
are to evolutionary prediction. In any case, the limits certainly cannot be
drawn very tightly. This means that evolution can explain a wide range of
outcomes. This means that any one particular outcome does not confer much
increased confidence in the validity of the hypothesis. Terry, you write:

"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."

Real examples of convergence are precisely why evidential claims, such as
the vitamin C pseudogene, constitute special pleading. The only examples of
"real" convergence we know are these mutational hotspots where identical
mutations are observed to occur independently. Hence claiming that the
vitamin C pseudogene mutations are evidence for common descent *is* special
pleading.

The massive and detailed convergence in biology was a surprise for, not a
prediction of, evolution. Nor do there exist unambiguous ways to distinguish
homologies from analogies. Ultimately it is both subjective and circular.
Subjective because the evolutionist must draw from a variety of criteria to
decide how make his judgement. Circular because he must assume evolution
occurred. Without first assuming evolution, then the evolutionist would have
to reckon with all the negative evidence which is being ignored.

David:

>>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.

Kuhn described those working within a scientific paradigm as doing "normal"
science. In normal science, the paradigm is assumed to be true, for purposes
of convenience, progress, and so forth. Normal science is not concerned with
proving the paradigm to be true, accumulating evidence and presenting it to
outsiders, etc. They've assumed it to be true and are working away.

In fact, it is tricky for normal science activities to cast their findings
as evidence because they have presupposed the paradigm to be true. The
evolution paradigm is so thoroughly baked in that it is difficult for
evolutionists to step outside the paradigm and make the case to an outsider.
It is difficult for them to seriously engage in the hypothesis: "could
evolution be false, and how do I counter this idea to someone who is not
committed to the paradigm?"

Instead of seriously engaging, what evolutionsts often respond with
speculative explanations, such as, "these designs are similar because they
arose from a common ancestor". Yes, we all know this is the explanation --
evolution can explain such similarities. And when they appear in distant
species we are told this is due to convergence. And when dramatic
differences are found in otherwise similar species, we're told of some freak
contingent explanation. But why is any of this *evidence* as opposed to mere
hand-waving explanation which amounts to little more than a tautology.

To make the case for evolution we need two things. First, we need good
strong evidences and arguments that do not fall apart under inspection. And
second, we need good defenses against the problems that exist. Right now we
have neither one of these.

--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

> Yes, evolution has it both ways because the pattern of data (to borrow a
> phrase from ID) has specified complexity that exactly corresponds to
> understood evolutionary mechanisms (i.e., that mutation is probablistic in
> being able to produce point mutations AND the environment exerts the same
> general physical "challenges" to form and function).
>
> This variety of possibilities is exactly what evolution would predict, but
> it such a mixture of true homologies and convergences is unlike any
> "intelligent design" that our human minds would likely envision.
>
> Douglas

====================

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
Received on Mon Sep 19 20:53:38 2005

This archive was generated by hypermail 2.1.8 : Mon Sep 19 2005 - 20:53:38 EDT