Icons of Evolution: Why Much of What We Teach About Evolution
Jonathan Wells, Regnery, Washington (DC), 2000
By Massimo Pigliucci
Department of Ecology and Evolution,
SUNY @ Stony Brook
Originally appeared in
Vol. 51, No. 5, pp. 411–414
Because there are omissions,
simplifications, and inaccuracies in some general biology textbooks, obviously
the modern theory of evolution must be wrong. This is the astounding line
of reasoning that provides that backbone of Jonathan Wells' Icons of Evolution.
It is the latest book in a series of neo-creationist
productions, (this one dressed
with the slightly more respectable label of "intelligent design theory"
[Pigliucci 2000a]), to drive a wedge into the perceived perniciousness of
modern science, and of biology in particular. This is another astonishing
example of the fact that evolution-deniers seem to consider attacks on
science popularizing as genuine intellectual feats, as if they had found
huge wholes in the primary literature that truly constitutes the core of
any respectable science.
Wells is a fellow of the
Center for the Renewal of Science and Culture, which has been at the forefront
of the neo-creationist assault on science over the last few years. Predictably,
his book is endorsed by other fellows of the same institution
and luminaries of the evolution-deniers movement such as Michael Behe (author
of Darwin's Black Box), Phillip Johnson (Darwin on Trial and The Wedge
of Truth, among others) and Dean Kenyon (Biochemical Predestination and
Of Pandas and People). Wells himself seems particularly well positioned
to engage in this never-ending debate given his double PhD in theology
and molecular biology. Alas, Icons falls far short of a critique of evolutionary
theory, or indeed of any significant contribution to the "evolution wars."
Wells' idea is simple: In
the ten chapters that make up most of the book, he tackles an equal number
of what he calls "icons," -that is, myths- of evolutionary biology, attempting
to show that biology textbooks don't tell the whole story, are out of date,
or oversimplify what is known. From there he concludes that because these
icons are the best "proofs" of evolution, biologists don't have a
leg to stand on and they should once and for all abandon their ideological
positions and open their minds to a truer and better science, which of
course must include the possibility of intelligent supernatural design
There are several flaws with
this line of reasoning, which I will examine in turn. First, textbook examples
are no "proof" of anything. Second, Wells's critique of the ten icons is
much less devastating than he seems to think. And third, science simply
doesn't work the way Wells apparently conceives it.
The fact that science (not
only biology) textbooks contain plenty of oversimplifications and inaccuracies,
and occasionally even major conceptual errors, is not news to anybody and
has always been decried by professional scientists and educators. There
are sadly understandable reasons for this state of affairs. For one thing,
general science textbooks are written by people who are either not practicing
scientists or are directly competent in a fraction of the topics
covered. Even when several authors collaborate, the situation does not improve
significantly. Second, textbooks (unlike technical research books) are
written largely to make money, both for publishers and for authors, and
academic rigor sometimes gets sacrificed to accommodate more pressing matters,
such as publishing deadlines. Third, pedagogical efficacy is often considered -rightly
or not- more important than scientific rigor; after all, the audience is
made of young students with little background in the discipline to be studied,
not of professionals who understand the subtleties of the subject matter.
Regrettable as these facts may be, to conclude from them that evolutionary
biology is a big lie constructed on thin evidence is analogous to the preposterous
suggestion of abandoning, say, quantum mechanics because many physics textbooks
do not portray it accurately or may even make egregious conceptual mistakes
in explaining it. It just doesn't follow, and it is pure wishful thinking
on Wells's part to pretend otherwise.
As for the icons themselves,
I will have to limit myself to a brief discussion of a couple of them. Let me therefore consider the first and last -and perhaps the most
important- of the "icons": the Miller-Urey experiments on the origin of
life, and the current status of the research on the origin of humans.
As is well known, in 1953
Stanley Miller-at the time a student of Urey-published a historical paper
in which he demonstrated the possibility of the inorganic synthesis of
some of the fundamental building blocks of life, given conditions that
were thought to resemble those of the ancient earth. This experiment is
still presented in many textbooks as the scientific answer to the question
of the origin of life. And Wells is right in maintaining that it shouldn't
be. For one thing, even if we do accept Miller's results at face value,
they are far from constituting an answer to the origin of life question.
At most they provide an interesting beginning. More importantly, the recent
consensus among geochemists is that the ancient earth atmosphere was essentially
chemically neutral, not reducing like the one Miller simulated.
However, textbooks should
still devote space to Miller's experiment for its historical (and pedagogical)
value: not only it was the first modern piece of empirical research on
the origin of life, thereby taking the whole field away from metaphysical
speculation, but it is also a great example of how science progresses by
questioning its own assumptions and results.
As for this being an icon
of evolution in Wells' sense, there are two problems with his position.
First, Wells gives his readers the completely misleading impression that
the field of research on the origin of life is still at the level of Miller's
1953 experiment, and that given the questionable validity of the latter,
the whole enterprise is in disarray. Au contraire, this is an area of extremely
fecund theoretical and empirical activity, with new hypotheses, findings
and experiments being published at a very rapid pace (Lahav 1999; Fry 2000).
More to the point of the creation-evolution debate, the Miller experiments
and the whole question of the origin of life have nothing to do with the
truth or lack thereof of evolutionary theory. By definition, evolution
is something that happens after life originates on a planet, and cannot
be invoked to answer the question of how this happened. By the same token,
evolutionary theory cannot be blamed for not being able to solve the problem
of the origin of life even if the latter might remain a mystery forever.
It is certainly true, as creationists are fond of saying, that evolution
requires life to have originated, but the two are entirely distinct scientific
questions, addressed by different fields of research. For that matter,
evolution also requires a universe to exist beforehand, but nobody would
say that if we don't understand the origin of the universe this is a fatal
blow to Darwinism (well, actually, naive young-earth creationists such
as Duane Gish do, but that is another story: Pigliucci 2000b, chapter 11).
The "ultimate" icon in Wells'
book concerns the story of human descent. This is perhaps one of the most
peculiar chapters in the entire book, because even Wells is forced to concede
ample ground to the evolutionists! He begins the chapter with the usual
complaint about the naive scientists that were fooled by the "Piltdown
man" hoax in 1912. I know of several scientists who feel the sting of shame,
that Wells wants them never to forget, because of science having been duped
by a fraudulent finding. But Piltdown was neither the first nor the last
practical joke scientists will ever face. Furthermore, it is yet another
beautiful example-which textbooks should promote-of how science really
works. It is true that this alleged intermediate between humans and chimps
was more or less accepted (not without challenge) for several decades.
However, it is also true that the human fossil record at the time was so
scant that it was very difficult to raise substantive objections to the
Piltdown findings. More importantly, scientists-not creationists-uncovered
the hoax, a development prompted by the very fact that more and more discoveries
of genuine human and proto-human fossils made it quite clear that Piltdown
didn't fit anywhere in the emerging picture. Since science works by a consilience
of evidence (Wilson 1998), it was the progress of science in virtue of
its self-correcting mechanisms that prompted evolutionists to reject Piltdown
and eventually uncover the fraud. I have yet to find a similar example
of acknowledgement of error in the evolution-denying literature, despite
the fact that such errors have been ubiquitous in that literature.
Wells, as much as he desperately
tries to debunk what to him is the most crucial component of evolutionary
theory, the history of human descent, is backed against the wall by his
own knowledge of biology. Unlike more naive creationists, he has to grudgingly
admit that "Many human-like fossils have been found since 1912, and unlike
Piltdown they appear to be genuine. Some have distinctively ape-like features,
while others are more human-like" (p. 218) and "Obviously, the human species
has a history" (p. 223). So much for destroying the ultimate icon.
But perhaps the most damning
point about Wells' book is the general conception of science that it emerges
from it. Given his scientific training, he should have known better. It
is clear that either the education system at Berkeley has failed in his
case, or that Wells does indeed have an ideological agenda (which he was
forced to admit in a public debate with me at the University of Tennessee.
See http://burns.tns.utk.edu/research/cb/evdebate.htm). Wells' whole argument
hinges on the idea of the crucial proof of a scientific theory. If that
pillar fails, the whole enterprise is useless. Now, Wells is far from showing
that any of the icons are in fact fundamentally flawed or represent an
insurmountable obstacle for evolutionists. But even if he succeeded, Wells'
conception of science is so simplistic as being labeled by philosophers
of science as "naive falsificationism."
Falsificationism, it may
be recalled, is the idea proposed by philosopher Karl Popper (1968) that
any amount of positive evidence is not enough to sustain a theory unless
such theory also makes predictions that could-in principle-being demonstrated
to be wrong, i.e., the theory is potentially falsifiable. Popper, however,
did not advocate discarding a scientific theory at the first sign of trouble.
Indeed, Thomas Kuhn clearly showed that real science is a lot more messy
and that before switching paradigms the amount of trouble has to be substantial,
or one risks living in a perennial state of flux in which no progress is
actually possible (Kuhn 1970). The real "evidence" for evolution is not
to be found in individual experiments, and it is certainly not to be expected
in textbooks for beginning students. Rather, it is found in the enormous
amount of facts about the biotic world that accumulate every year in the
primary literature and that make no sense outside of the evolutionary paradigm.
Components of this paradigm are constantly being tested in countless laboratories
around the world, and-for the most part-the theory has withstood the test
of time. More importantly, this is the way science really works, regardless
of Wells' naive and ideologically motivated views that it should be otherwise
(he admits in an online article, available at http://www.tparents.org/library/unification/talks/wells/DARWIN.htm,
that he enrolled in his second PhD-in molecular biology-for the express
purpose of "destroying Darwinism").
What have we to learn from
this latest attempt at debunking evolution? Two things. First, that it
is indeed a good idea to pay more attention to how our textbooks are written.
This is not just so that individuals like Wells will not be able to use
their cheap ammunition in a public debate, but more importantly because
the "icons" can actually be properly used to show students that science
is an engaging and ever changing enterprise, not a monolithic block of
static knowledge. Second, we should finally get the message that evolution
deniers are always at work, and that they are making inroads with both
the public and politicians. How long until we get out of the ivory tower
and start defending reason and science, as well as doing a better job at
Acknowledgments. I wish to
thank the following people for a critical reading of this manuscript and
for providing me with valuable insights and suggestions: Wesley Elsberry,
Jim Foley, Carl Johnson, Niall Shanks, Frank Steiger, and Dave Ussery.
Dembski, W. A. 1998. Reinstating
design within science. Rhetoric & Public Affairs 1:503-518.
Fry, I. 2000. The Emergence
of Life on Earth: a Historical and Scientific Overview, New Brunswick (NJ): Rutgers
Kuhn, T. 1970.
of Scientific Revolutions, Chicago: University of Chicago Press.
N. 1999. Biogenesis. Oxford (UK): Oxford University Press.
Pigliucci, M. 2000a. Review of
The Design Inference, by William Dembski. BioScience 50: 79-81.
Pigliucci, M. 2000b. Tales
of the Rational: Skeptical Essays About Nature and Science. Atlanta:
Popper, K. R. 1968. Conjectures
and refutations; the growth of scientific knowledge. New York: Harper & Row
Wilson, E. O. 1998. Consilience: the unity of knowledge.
New York: Knopf.