ABSTRACT: We agree that the educational literature needs reform, but we
must be careful just what KIND of "reform" we call for. (We also seem to
agree that some data supports limits to variation, but that
macroevolution's extrapolations have some justification as well.)
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Regarding "limits on variation" and macroevolution:
>LH>"Macroevolution does not require "no limits" on variability....
DT> There is something useful to discuss here: as limits of some
> form ARE recognised within macroevolutionary theory. So, for
> example, it would appear that [almost] no new phyla have appeared since
> the Cambrian explosion, so something is acting to block change
> here. Evolutionary radiations seem to apply at the species and
> genus level. Transitions at higher taxonomic levels are the ones
> which are crucial to answering the question as to whether there
> are block-type limits to variation. It is true that empirical data
> are over short timescales - but this means we either have to be
> clever in designing experimental work, or that we must accept that
> our theoretical ideas cannot progress beyond hypothesis.
True.
> LH> " ... we need to extrapolate. As we all know, extrapolation is
> > one of science's greatest dangers. ... When we do it, we need to
> > justify it."
> > "First, there is the genetic data ..."
DT> My own view is that homologies are consistent with both
> common ancestry theories and explanations involving creative
> design. "Normal science", in a Kuhnian sense, can take place
> using such data within both paradigms.
> LH> "Second, there seems to be no sharp line between microevolution
> > and macroevolution...."
DT> This brings us back to Basic Types - where observational
> evidence for very close developmental pathways exist. It can be
> hypothesised that all the organisms within a Basic Type are
> related by common ancestry - despite the variations which, as you
> say, go well beyond those accomplished by artificial breeding.
> A great gulf separates one Basic Type from any other - and this
> is where I would call a halt to extrapolation.
Fair enough.
DT> Reference has been made on this Reflector to the writings
> of Professor Brian Goodwin: he is one of the few biologists to
> spell out the implications of recognising Basic Types in the
> living world - and to suggest that much neoDarwinian literature
> is failing to address the real issues in biology. I applaud him
> for making an effort to redefine these issues and to translate
> them into research programmes. However, he is very much a lone
> voice here in the UK.
I eagerly anticipate the world's "genetic database" growing. It will
do much to answer whether there are great gulfs separating Basic Types,
which would support limits on variation -- or whether there are no great
gulfs but rather smooth transitions to higher taxa, which would support
macroevolution's extrapolation. (Although I fear the answer will be quite
muddy for quite some time. :-)
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I agree that there is data to support the hypothesis that mutational
variation could be limited to the family/genus/species level, and that
this hypothesis could be used to guide investigations. I think we also
agree that there is some evidence to support the extrapolation from
microevolution to macroevolution, but that the popular and educational
literature often glosses over an honest evaluation of this evidence in
favor of grandiose claims. Which leads us too....
> LH> " ... we need to extrapolate. As we all know, extrapolation is
> > one of science's greatest dangers. ... When we do it, we need to
> > justify it."
> >
DT> Agreed. I hope, then, that you will concur with the views
> expressed by Phillip Johnson that much of the literature
> advocating neoDarwinism is defective - making grandiose
> extrapolations from the data we have without the crucial
> justification for those extrapolations. When there is agreement
> that there is an urgent need to reform educational literature,
> we will have made some progress.
While I substantially concur, the brush stroke used is a little too broad
for my taste.
First, we should distinguish between (at least) three types of literature:
--Professional literature (journals and graduate textbooks)
--Educational literature (middle/high school and early college textbooks)
--Popular literature (books, articles, public debates)
Second, we must remember that scientists are an excitable lot. When we
catch glimpse of an hypothesis which just might tie together a number of
disparate and puzzling data, we're worse than first-time grandparents with
pictures -- we show it off and brag about it to anyone who will listen,
long before the claims we make are empirically warrentted. Although this
sort of thing should be carefully editted out of educational literature
(without diminishing the "joy of discovery"), and while it is usually
spotted for what it is in the professional literature, some allowances
need to be made for it in the popular literature.
So just what are the defects and "unjustified grandiose extrapolations"
found in neo-Darwinian literature? Here are three that I have
encountered:
1) The claim that the data, and macroevolutionary theory in general,
supports the "no-Creator" hypothesis.
2) The glossing over of macroevolution's "weak areas" (such as the origin
of life, origins of higher taxa, and origins of novel biological
structures, complexity, and genetic information), offering mere
"hand-waving solutions" without serious justification, and not giving fair
treatment to the serious objections which have been raised.
3) The dismissal of the possibility that a Creator could have guided
evolution and, perhaps, performed supernatural miracles at strategic
points in biological history (e.g. to overcome the "weak areas").
In my mind, the first defect is the worst, and the one we should address
most forcefully. It has no place in the educational or professional
literature (nearly EVERY scientist would agree with this), and it should
be exposed in the popular literature, whenever possible, for the
philosophical blunder and religious bias that it is.
The second defect should be addressed if for no other reason than that it
is harmful to scientific progress. The scientific community as a whole
needs to know where its theories are _weakest_ so that those areas can be
the focus of research, rather than ignored. Scientific literacy in the
general public is advanced when it knows just _what_ scientists have
figured out, and what they are still working on. At all levels of
literature, the more honest the evaluation of the data, the better.
The third defect is the trickiest one to address in the educational
literature, especially given the public school climate here in the U.S.
Given the large number of people, including scientists, who support this
possibility, I do think an "acceptable" way can, and should, be found to
offer this hypothesis as one way of dealing with the "weak areas" of
evolutionary theory.
So if I am asked to support educational literature reform which [1]
opposes all "no-Creator" bias, [2] makes a fair and honest assessment of
the areas where the data is weak or contradictory to macroevolution's
claims, and [3] at some point, carefully offers the hypothesis of an
Intelligent Designer (and Assembler) as one possible "solution;" then you
will have my support.
If on the other hand I am asked to support educational literature reform
which proposes that [1] the "weak areas" of macroevolution are _evidence_
for supernatural activity in biological history and [2] are _evidence_
that people only believe in macroevolution because of a philosophical bias
towards (or a theology tainted by) Naturalism; then I must decline.
I hope I'm not starting a new argument. :-) I just think it is important
that we understand more precisely what _kind_ of reform we ask for.
Thanks again for your excellent posts.
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"... Another victim of applied metaphysics." | Loren Haarsma
--Hobbes (_Calvin_and_Hobbes_) | lhaarsma@opal.tufts.edu