>Chris
>I said in my original post on the topic:
>"To determine whether Johnson had any valid point at all
>would require determination of details that he does not seem concerned to
>bother with."
Yes, in a thread you entitled "Johnson Blows It Again," you sandwiched
this point between the claims, " Evolution proceeds much more slowly
in stable environments," and " Evolution is *definitely* not to be regarded
as always proceeding at a constant rate." It took this to mean that
Johnson blew it by ignoring this detail.
>I gave an explanation that would be expected to hold *if* certain conditions
>held. I did not claim that those conditions *did* hold.
It looks to me like you were:
" Since the *main* function of selection is actually the restriction or
*prevention* of evolution, it is not hard to understand that, in a stable,
steady, undersea environment, once organisms got locally optimized for their
niche in the environment, nearly *any* genetic variation would be culled
out."
Remember, that this was all part of a reply to something Johnson
wrote.
>What I was pointing
>out was that the fact of little or no discernible evolution over a period of
>time *by itself* would not refute evolutionary theory. Hence the "Not
>necessarily* with which I began my comments. My explanation assumed
>hypothetically the situation where there is very little environmental change
>*and* organisms are optimized for their current niches. Perhaps Mike missed
>this part of my remarks.
Perhaps I was thrown off balance by the *title* of your thread. It looks
clear to me that you were trying to refute Johnson's claim by noting
that contrary to his claim, "a stable, steady, undersea environment,"
would be "exactly the environments in which we would *not*
expect to see the most evidence for evolution." You didn't
title your thread, 'Johnson could be blowing it,' now did you?
I have no desire to quibble further, so I'll simply leave it to
each reader to decide for themselves.
>If the organisms were significantly *non-*optimized for their environment,
>we would see relocation, extinction, or evolutionary change, even in an
>unchanging environment.
>And, if the environment is *not* stable, then we should expect evolutionary
>change.
>Only in the case where optimization is "complete" (within the reach of small
>genetic changes) *and* the environment puts selective pressure on organisms
>to *stay* as they are, *will* they stay the way they are.
>In fact, if it turned out that the period in question showed no evolutionary
>development *and* it was known that environmental changes were fairly
>continuous, severe, and long-lasting (i.e., lasting long enough to put
>selective "pressure" on organisms that should result in significant change),
>*THEN* we could say that something was wrong with evolutionary theory.
This sounds good, but let's take a closer look.
1. What do you mean by "evolutionary development?"
2. How are we to know if the environmental changes were continuous,
severe, and long-lasting?
3. How do we define 'severe?' How long is "long'lasting?"
4. What distinguishes significant change from non-significant change?
Unless we can nail down these questions, there seems no hope
of detecting if something is wrong with "evolutionary theory."
>Moral of the story?
>1. Evolutionary theory is more complex in the working out of its
>implications than Mike is willing to acknowledge.
What makes you think I am unwilling to acknowledge this?
That's a might strong claim to attribute to me.
>2. Try not to too closely emulate Stephen's tendency to misrepresent your
>opponent's views by ignoring context and qualifiers.
I was certainly not trying to misrepresent you. Maybe you should
be more careful and make sure your thread titles don't misrepresent
the points you are making.
>3. Evolutionary theory is not as "plastic" as Mike would have us believe.
If you are going to preach against being misrepresented, may I point
out that I said nothing about "evolutionary theory?" I was speaking
of the Darwinian interpretation of evolution. Evolution deals with
common descent and darwinism deals with the proposed mechanism.
Your response to Johnson focused on the mechanism. And I think
you've shown just how plastic it can be.
>It is *certainly* vastly less "plastic" in this respect than designer theory,
>which can "explain" not only what *does* or *can* happen under evolutionary
>theory, but what *can't* happen under evolutionary theory, with no
>limitations *whatsoever*! Supporters of designer theory are *hardly* the
>ones to be talking about the "plasticity" of evolutionary theory, a theory
>in which there are no *conceivable* empirical observations that could
>falsify it, because it imposes no restrictions *at all* on what the
>empirical facts must be if it is to be true.
What "designer theory" am I supposed to be a supporter of? Personally,
I think the concept of intelligent design can be used in a way that is
far less plastic than the way darwinian interpretations have been used.
But that's another topic, as even if your claims are true, the inherent
plasticity of darwinism shouldn't be ignored. It's like a politician caught
using illegal campaign donations who responds by accusing the other
party of doing likewise (or even worse!).
Mike
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