From: rowe@pender.ee.upenn.edu (Mickey Rowe)
Newsgroups: talk.origins
Subject: Re: Topic for Discussion?
Date: 22 Jan 93 22:07:18 GMT
Organization: University of Pennsylvania

In article <1jo29o$srt@agate.berkeley.edu>
    philjohn@garnet.berkeley.edu (Phillip Johnson) writes:

>I am not sure that it is possible to hold a discussion in this
>group, because the majority of participants seem to consider the
>neo-Darwinian theory to be so obviously true that doubt is not
>taken seriously. 

I beg to differ.  I think it often seems that way, but to me that's
only because the "alternatives" that we're offered are so worthless.
I'm quite willing to entertain doubts.  I'm just looking for doubts
with substance.

> On that basis, what is there to discuss?

Obviously what there is to discuss is the evidence which causes you
(or anyone else) to doubt.

...

>I would say that it is reasonable for a well-informed observer to
>conclude that macroevolution (i.e. the creative process that
>produced complex plants and animals in the first place) is not 
>"cumulative microevolution" (i.e. the peppered moth example writ
>large over geological time).  

That's easily bought.

>If so, it is also reasonable to conclude that the mechanism of
>macroevolution is an unsolved mystery.

This does not necessarily follow.  There is a difference between, for
example, peppered moth populations changing color, and hermit crabs
losing their tails that actually necessitates a distinction.  Chris
hints at it himself later on in the post to which you refer:

     Bringing about a change in the gene pool assumes that there is
     genetic variation in the population to begin with, or a way to
     generate it.  Genetic variation is "grist for the evolutionary
     mill".  For example, if there were no dark moths, the population
     could not have evolved from mostly light to mostly dark. In order
     for continuing evolution there must be mechanisms to increase or
     create genetic variation (e.g.  mutation) and mechanisms to
     decrease it(e.g.  natural selection and genetic drift).

In the case of the moths, the population was already polymorphic at
the locus specifying the imago's pigmentation.  I suspect most people
would agree that by the time a population has speciated, the
descendent (or sister) contains new alleles and possibly new loci (I
don't mean to bias this in terms of a progression--of course alleles
and loci are also lost in lineages).  As such, "microevolution" can be
distinct from "macroevolution" without there being any mysteries (i.e.
we know of processes which will introduce both new alleles and new
loci).

Frequently the scenario is turned upside down here (tag John Livesay
:-).  Knowing what we know about different molecular biological
events, how could you *prevent* macro-evolution from occuring as
described (e.g. by Chris)?

>My impression is that many participants in this group think that
>the position stated in the preceding paragraph is unreasonable,
>and even in some sense reprehensible.  Is that correct?  

I'm not sure which "position" you're referring to.  Whether or not
"micro-" and "macro-" evolution are different, whether or not the
mechanisms of "macro-" evolution are mysterious, or whether or not
people should be encouraged to think that it's a mystery (or perhaps
something else).  To me it seems that science is all about
mysteries--some just further away than others from being solved.  My
impression is that people pick on "evolution" as more of a mystery
*not* because it's little understood, but rather because they don't
like what is understood (or at least as often because they don't like
what they *think* others understand).

>Phillip E. Johnson
>  School of Law, University of California, Berkeley CA 94720

Mickey Rowe     (rowe@pender.ee.upenn.edu)
Newsgroups: talk.origins