Stephen, regarding an exchange between David Tyler and myself, you wrote:
SJ> David
> On Thu, 10 Aug 1995 12:27:18 GMT you wrote:
>
> DT> "Second, there seems to be no sharp line between microevolution
> > and macroevolution. Consider the genetic and chromosomal
> > differences between, say, sheep and goats, or cows and camels --
> > which most of us on the reflector would, I believe, classify as
> > microevolution. Even these are beyond the "limits" which we have
> > so far induced by artificial breeding of animals. To call these
> > "microevolution" is already somewhat of an extrapolation. Where
> > then do you draw the line of limits, and how do you justify where
> > you draw that line?"
>
SJ> This is something that I have been thinking about but have been afraid
> to post! :-) It is common in creationist literature to accept micro-
> evolution (eg. Darwin's finches, Peppered Moth, etc), as explicable by
> natural causes, but not macro-evolution. Yet even some micro-evolution
> may not be 100% explicable by natural causes. I accept that Darwin's
> finches and the Peppered Moth are explicable by 100% natural causes,
> but am not so sure about others. Variation within species is empirically
> demonstratably but I am not so sure about the production of *all* new
> species or genera.
Amusingly enough, Stephen, David Tyler did not write that paragraph.
I did! This is an instructive example of how (part of) an argument
crafted to advance one point of view can wind up being interpretted and
quoted to advance a very different one. (I'm sure you've seen it
happen to your own writings. :-)
I think we're in agreement about at least three things here: [1] The
level of genetic/mutational variation which humans have produced through
artificial selection (or witnessed naturally within the space of recorded
human history) is, in general, LESS than the level of variation commonly
accepted (even by Recent Creationists and Progressive Creationists) as
"microevolution." [2] If there really is a smooth progression from
microevolution to macroevolution (e.g. if "proportional" genetic
homologies are shown to extend beyond the family/genus levels to higher
taxa), then it is inconsistent to claim that theoretical extrapolation is
UNjustified beyond some _arbitrarily_ drawn line between "micro" and
"macroevolution." (David Tyler correctly answered this point by saying
that _if_ the genetic data really shows that there are certain Basic
Types, with a "great gulf" between them, then such a cut-off line is
warrantted.) [3] We cannot rule out God's direct intervention in
microevolution or macroevolution.
Where we disagree, obviously, is: Given that biological evolution cannot
demonstrate 100% natural mechanisms, which model should we advocate?
------------------
SJ> As a Progressive Creationist I do not rule out direct divine intervention
> even in some so-called micro-evolution, until it can be demonstrated
> that a 100% natural mechanism exists in each case, that can get over
> the limits to variation that so evidently inhibits selective breeding
> in the real world.
You are correct not to "rule out" God's direct activity; I would not rule
out God's direct activity even if a 100% naturalistic explanation WERE
available.
But while it is one thing to refuse to "rule out" God's direct
intervention -- it is quite another for Christians to ACTIVELY ADVOCATE
(both "internally" within the church and "externally" in public debate)
models which include supernatural activity as a detectable cause! While
it is wise, prudent, and necessary for Christians to actively advocate
"supernatural" models in events such as the history of Israel or certain
kinds of human behavior, can the same be said for OTHER processes which
"cannot demonstrate 100% natural mechanisms," such as asteroid motion,
animal behavior, birth defects, or the origins of the AIDs epidemic?
The question has never been whether or not we should "rule out" God's
supernatural activity in biological history -- Theistic Evolutionists
don't do that! The question is whether or not the model which we actively
advocate, and which guides our research, should include supernatural
activity as a detectable cause. Clearly, the inability to "demonstrate
100% natural mechanisms" does not decide the question.
--------------------------------------------------------------------------------
In theory, there is no difference between | Loren Haarsma
theory and practice, but in practice | lhaarsma@opal.tufts.edu
there is a great deal of difference. |