More Articles on Evolution
More Crank Science
Jerry A. Coyne
Just as evolutionary biologists were getting used to the attacks of Biblical
creationists, we are now being goaded by a new species of gadfly: the academic
anti-evolutionist. Unlike our old foes, these critics, personified by David
Berlinski, Phillip Johnson, and Michael Behe, possess respectable academic
credentials, and, if their views are rooted in religion, keep it to themselves.
They do, however, share several features with religious creationists. Both
groups lack formal training in evolutionary biology, do not publish their
views in the professional scientific literature, and see evolutionists as
a beleaguered lot, zealously guarding a shopworn Darwinism that we secretly
distrust. Moreover, like Behe's "argument from complexity," many of the anti-evolutionists'
arguments are identical to those of Biblical creationists, merely gussied
up a bit for academic consumption. (It is instructive, for instance, to compare
Phillip Johnson's treatment of the fossil record in Darwin on Trial
with that of Duane Gish in Evolution: The Fossils Say No!.)1
Behe has been particularly influential because he is a genuine biochemist.
Allen Orr's estimable critique of Darwin's Black Box shows, however,
that Behe's central argument about "irreducible complexity" is deeply flawed.
Although Orr uses scientific ammunition to demolish this argument, one should
not assume that Darwin's Black Box is itself a serious work of science.
The book bears many traces of "crank science," that fringe genre that includes
the study of homeopathy, polywater, and cold fusion:
1. Behe has deliberately avoided presenting his views directly to the scientific
community. He has not published or (as far as I know) attempted to publish
his criticisms of Darwinism in the professional literature, nor sought input
from reputable evolutionists (none are acknowledged in his book). Darwin's
Black Box bypasses scientists to reach a public likely to be impressed
by Behe's credentials as a biologist, aided by a publisher who seems to care
more for profit than for accuracy (let us remember that the Free Press, a
division of Simon & Schuster, also published The Bell Curve). As Orr
makes clear, Behe's knowledge of evolutionary biology is superficial, deriving
not from the technical literature but from more popular works by Gould, Dawkins,
and others.
2. As I have noted in my own review of Darwin's Black Box,2 Behe's theory of biochemical complexity is not scientific because
it is untestable: there is no observation or experiment that could conceivably
refute it. His theory is a hybrid, maintaining that some biochemical pathways
evolved while others were assembled by an unidentified Great Designer. What
cannot be explained by Darwinism must therefore fall to intelligent design.
Such an idea cannot be falsified because each time a biochemical pathway receives
an evolutionary explanation, Behe can simply narrow the Designer's domain
to include the pathways not yet explained.
3. Despite the lack of scientific feedback on his views, Behe makes exaggerated
claims for their importance. He likens himself to Newton, Einstein, and Pasteur,
but claims that a defensive band of evolutionists blocks his ascendancy to
the pantheon. Such declarations of unrecognized genius are a diagnostic feature
of crank science.
4. Finally, Behe's arguments, like those of Biblical creationists, are heavily
larded with quotations from evolutionists, many taken out of context to make
it seem that our field is riven with self-doubt. More than anything else,
it is this use of selective quotation that shows Behe's close kinship to his
religious predecessors.
I am painfully and personally acquainted with Behe's penchant for fiddling
with quotations. On page 29 of Darwin's Black Box he writes:
Jerry Coyne, of the Department of Ecology and Evolution at the University
of Chicago, arrives at an unanticipated verdict: "We conclude--unexpectedly--that
there is little evidence for the neo-Darwinian view: its theoretical foundations
and the experimental evidence supporting it are weak."
Apparently I am one of those faint-hearted biologists who see the errors
of Darwinism but cannot admit it. This was news to me. I am surely numbered
among the more orthodox evolutionists, and hardly see our field as fatally
flawed. The paper in question (actually by Allen Orr and myself)3
addresses a technical debate among evolutionists: are adaptations based on
a lot of small genetic mutations (the traditional neo-Darwinian view), a few
big mutations, or some mixture of the two? We concluded that although there
was not much evidence one way or the other, there were indications that mutations
of large effect might occasionally be important. Our paper cast no doubt whatever
on the existence of evolution or the ability of natural selection to explain
adaptations.
I went back to see exactly what Orr and I had written. It turns out that,
in the middle of our sentence, Behe found a period that wasn't there. Here's
the full citation, placed in its context:
Although a few biologists have suggested an evolutionary role for
mutations or large effect (Gould 1980; Maynard Smith 1983: Gottlieb, 1984;
Turner, 1985), the neo-Darwinian view has largely triumphed, and the genetic
basis of adaptation now receives little attention. Indeed, the question is
considered so dead that few may know the evidence responsible for its demise.
Here we review this evidence. We conclude--unexpectedly--that there is little
evidence for the neo-Darwinian view: its theoretical foundations and the experimental
evidence supporting it are weak, and there is no doubt that mutations of large
effect are sometimes important in adaptation.
We hasten to add, however, that we are not "macromutationists" who believe
that adaptations are nearly always based on major genes. The neo-Darwinian
view could well be correct. It is almost certainly true, however, that some
adaptations involve many genes of small effect and others involve major genes.
The question we address is, How often does adaptation involve a major gene?
We hope to encourage evolutionists to reexamine this neglected question and
to provide the evidence to settle it.
By inserting the period (and removing the sentence from its neighbors), Behe
has twisted our meaning. Our discussion of one aspect of Darwinism--the relative
size of adaptive mutations--has suddenly become a critique of the entire Darwinian
enterprise. This is not sloppy scholarship, but deliberate distortion.
Perhaps I unduly belabor this point, but we know what they say about God
and the details. Can anyone who alters quotations be trusted to give an unbiased
view of the scientific data?
One of the blurbs on the cover of Darwin's Black Box was contributed
by Peter Van Inwagen, a professor of philosophy at Notre Dame (Behe apparently
had trouble finding biologists to endorse his book): "If Darwinians respond
to this important book by ignoring it, misrepresenting it, or ridiculing it,
that will be evidence in favor of the widespread suspicion that Darwinism
functions more as an ideology than as a scientific theory. If they can successfully
answer Behe's arguments, that will be important evidence in favor of Darwinism."
Behe has been answered. Can we now expect him to retract his views? I'm not
holding my breath.
1 Phillip Johnson, Darwin on Trial (Washington,
DC: Regnery Gateway, 1991); Duane T. Gish, Evolution: The Fossils Say No!
(San Diego: Creation-Life Publishers, 3rd ed., 1979).
2 J. A. Coyne, "God in the Details," Nature 383
(1996): 227-28.
3 H. Allen Orr and Jerry A. Coyne, "The Genetics of Adaptation:
A Reassessment," The American Naturalist 140 (1992): 725-42.
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