> >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."
Chris
This looks straightforward enough to me.
> Remember, that this was all part of a reply to something Johnson
> wrote.
Chris
In which he lied and claimed that, in effect, the undersea environment *was*
stable (the only *possible* condition under which no evolution would occur)?
> >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?
Chris
See above. He *STILL* blew it, no matter which way we take his remarks. If
it is *true* that there was no evolution, then it *requires* that the
environment be stable and that the organisms be locally optimized (if
evolution is impossible, then significantly unsteady environments will
simply kill many of them off). But, if it's true that significant evolution
*did* occur during the times in question, why is Johnson telling us that it
*didn't*? Either way, Johnson blew it.
I don't happen to have much knowledge of the period in question, so I, being
an utter fool, took the demagogue at his word. If you want to bitch at
someone for having a "plastic" theory, go talk to Johnson, whose theory is
so plastic that reality and logic simply make no difference to him.
>
> 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?
One way we can tell is by geological examination of sediments, etc. These
will give evidence of local conditions over time. If exactly the same
minerals and other indicators are settling out at the same rate (and in the
same ratios) for a long period of time, it's a good indicator that the
environment was not changing much. Another indicator is the fossils
themselves, which will at least indicate whether the organisms in the area
were optimized for their environments or not (if they are evolving fairly
continuously and rapidly, they are *not* optimum because they are still
responding to selective pressures).
>
> 3. How do we define 'severe?' How long is "long'lasting?"
Chris
Severe: Strong enough to differentially select variants that would
previously have been culled out.
Long lasting: Long enough for evolution to take place (a single disturbance
lasting but a few hours and then never recurring for millions of years
obviously does not qualify). For some bacteria, "long lasting" might only be
a few years. But, since, I assume, we are talking about organisms that leave
larger fossils, such periods would, I'd guess, have to be at least hundreds
of years.
>
> 4. What distinguishes significant change from non-significant change?
Chris
Whether it imposes selective pressure or not. A change of water temperature
of 1 thousandth of a degree (on average) for a period of years would not
normally be significant (though, theoretically, I suppose some organism
could be right on the verge of blooming or dying out, and even such a small
change could be significant if it's biochemistry just *happened* to be tuned
to such precision that such a change triggered biological processes that
would not otherwise occur).
> Unless we can nail down these questions, there seems no hope
> of detecting if something is wrong with "evolutionary theory."
Yes and no. Obviously, more precision is better. But, the fact that we can
infer that *no* evolution over a long period of time implies that the
environment is much more steady than would be implied by *lots* of evolution
over the same period (given the same initial conditions) is valuable in
itself. At least we can claim that there *is* a relationship of this type
between organisms and their environments. Designer theory offers nothing
even *remotely* comparable.
>
> >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.
Chris
What made me think that was that you tried to turn my use of evolutionary
theory for "predictive" purposes into a *failure* of the theory, into a
symptom of "plasticity," etc., without realizing that such conditions would
be implied by evolutionary theory if Johnson's claim had been true, thus
showing not the *failure* of the theory but it's cognitive power to work
backwards from the occurrence or non-occurrence of evolution to conclusions
about the environment. Obviously, if it were as plastic as you suggest, this
would not be meaningfully possible.
>
> >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.
Chris
You may have shown how plastic the terminology may be, but that's all. I
don't like to use the term "Darwinism" much at all, precisely because it has
so many meanings, ranging from Darwin's original views to what seem to me to
be views essentially *compatible* with Darwin's actual views, but going
rather far beyond them. Johnson, in fact, seems to *deliberately* play on
this ambiguity (in "Darwin on Trial") sometimes pretending only to refute
*Darwin's* views, and sometimes implying that he has refuted purely
naturalistic evolutionary theory *in general*.
I took you to mean what I have taken to calling NET or Naturalistic
Evolutionary Theory: The view that evolution occurs by *some* purely
naturalistic mechanism(s) of variation combined with natural selection or
cumulative culling by virtue of organisms' relationships with their
environments.
Mike
> >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!).
Chris
See my remarks above. You are confusing strict inference from theory and
Johnson's alleged fact with plasticity.
But, also, since scientific theories are never proved by the kind of
deductivity that characterizes conclusions in mathematics or much of
philosophy, we frequently have to choose theories to go with based on such
issues as "plasticity," the richness and solidity of empirical implications
that can be used for testing, compatibility and complementarity with
knowledge in other sciences, etc. Evolutionary theory is more "plastic"
than, say, Newtonian physics, but it is vastly less "plastic" than
alternative theories that are known and have not already been empirically
refuted. An example is *any* version of designer theory that *is* truly
designer theory (of course, "designer" theory can be made to have the same
degree of strictness that NET has by sneaking NET into it to provide the
sole mechanism by means of which a Deistic type of designer could "design"
life, but this simply makes the designer himself essentially irrelevant to
the theory).
If you think designer theory can be made so good, why haven't we seen *any*
examples of *any* of the types of inference I made with respect to Johnson's
alleged fact? If *no* discernible change over a geologic period of time
occurs, despite a good fossil record, can we *use* designer theory to
determine anything about the environment and the relationship of the
organisms to that environment?
No?
Why not?
Simple: *Regardless* of what happens, the designer did it. Any further
explanation is either reading the mind of the designer or is not designer
theory. Since we don't have an empirical theory of the designer's mind and
plans for the future (or the past), there are *no* predictive implications
to be drawn from the positing of a designer.
And yet, such implications are absolutely *necessary* to avoiding
"plasticity." So, if you think you can make it even *slightly* less plastic
than NET, as you seem to think it can, why have *NONE* of all the dedicated
ID theory people come up with even the *beginnings* of such a theory.
Remember, designer theory has been around for nearly two hundred years, at
least (since Paley's famous watch argument). Further, it has had far more
believers and supporters than has evolutionary theory. Why then, has there
been *no* progress toward the development of a viable *non-*plastic ID
theory? Why is it that we can derive no more empirically testable
implications from designer theory now than we could in 1802?
Can we *use* designer theory in *any* scientifically meaningful way, despite
the fact that it's far older than Darwin's theory or any NET derived from
it?
No?
Why not?
This archive was generated by hypermail 2b29 : Mon Jan 24 2000 - 23:18:35 EST