INTRODUCTION to ICONS of EVOLUTION: Science or Myth? Why much of what we teach about evolution is wrong
by Jonathan Wells
"Science is the search for the truth," wrote chemist Linus Pauling, winner
of two Nobel prizes. Bruce Alberts, current President of the U. S. National
Academy of Sciences, agrees. "Science and lies cannot coexist," said Alberts
in May, 2000, quoting Israeli statesman Shimon Peres. "You don't have
a scientific lie, and you cannot lie scientifically. Science is basically
the search of truth." For most people, the opposite of science is myth.
A myth is a story that may fulfill a subjective need, or reveal something
profound about the human psyche, but as commonly used it is not an account
of objective reality. "Most scientists wince," writes former Science editor
Roger Lewin, "when the word 'myth' is attached to what they see as a pursuit
of the truth."
Of course, science has mythical elements, because all human enterprises
do. But scientists are right to wince when their pronouncements are called
myths, because their goal as scientists is to minimize subjective story-telling
and maximize objective truth. Truth-seeking is not only noble, but also
enormously useful. By providing us with the closest thing we have to a
true understanding of the natural world, science enables us to live safer,
healthier and more productive lives. If science weren't the search for
truth, our bridges wouldn't support the weight we put on them, our lives
wouldn't be as long as they are, and modern technological civilization
wouldn't exist. Story-telling is a valuable enterprise, too. Without stories,
we would have no culture. But we do not call on story-tellers to build
bridges or perform surgery. For such tasks, we prefer people who have
disciplined themselves to understand the realities of steel or flesh.
The Discipline of Science
How do scientists discipline themselves to understand the natural world?
Philosophers of science have answered this question in a variety of ways,
but one thing is clear: Any theory that purports to be scientific must
somehow, at some point, be compared with observations or experiments.
According to a 1998 booklet on science teaching issued by the National
Academy of Sciences, "it is the nature of science to test and retest explanations
against the natural world." Theories that survive repeated testing may
be tentatively regarded as true statements about the world. But if there
is persistent conflict between theory and evidence, the former must yield
to the latter. As seventeenth-century philosopher of science Francis Bacon
put it, we must obey Nature in order to command her. When science fails
to obey nature, bridges collapse and patients die on the operating table.
Testing theories against the evidence never ends.
The National Academy's booklet correctly states that "all scientific knowledge
is, in principle, subject to change as new evidence becomes available."
It doesn't matter how long a theory has been held, or how many scientists
currently believe it. If contradictory evidence turns up, the theory must
be reevaluated or even abandoned. Otherwise it is not science, but myth.
To insure that theories are tested objectively and do not become subjective
myths, the testing must be public rather than private. "This process of
public scrutiny," according to the National Academy's booklet, "is an
essential part of science. It works to eliminate individual bias and subjectivity,
because others must also be able to determine whether a proposed explanation
is consistent with the available evidence." Within the scientific community,
this process is called "peer review." Some scientific claims are so narrowly
technical that they can be properly evaluated only by specialists. In
such cases, the "peers" are a handful of experts. In a surprising number
of instances, however, the average person is probably as competent to
make a judgment as the most highly trained scientist. If a theory of gravity
predicts that heavy objects will fall upwards, it doesn't take an astrophysicist
to see that the theory is wrong. And if a picture of an embryo doesn't
look like the real thing, it doesn't take an embryologist to see that
the picture is false.
So an average person with access to the evidence should be able to understand
and evaluate many scientific claims. The National Academy's booklet acknowledged
this by opening with Thomas Jefferson's call for "the diffusion of knowledge
among the people. No other sure foundation can be devised for the preservation
of freedom and happiness." The booklet continued: "Jefferson saw clearly
what has become increasingly evident since then: the fortunes of a nation
rest on the ability of its citizens to understand and use information
about the world around them." U. S. District Judge James Graham affirmed
this Jeffersonian wisdom in an Ohio newspaper column in May, 2000. Graham
wrote: "Science is not an inscrutable priesthood. Any person of reasonable
intelligence should, with some diligence, be able to understand and critically
evaluate a scientific theory."
Both the National Academy's booklet and Judge Graham's newspaper column
were written in the context of the present controversy over evolution.
But the former was written to defend Darwin's theory, while the latter
was written to defend some of its critics. In other words, defenders as
well as critics of Darwinian evolution are appealing to the intelligence
and wisdom of the American people to resolve the controversy. This book
was written in the conviction that scientific theories in general, and
Darwinian evolution in particular, can be evaluated by any intelligent
person with access to the evidence. But before looking at the evidence
for evolution, we must know what evolution is.
What is Evolution?
Biological evolution is the theory that all living things are modified
descendants of a common ancestor that lived in the distant past. It claims
that you and I are descendants of ape-like ancestors, and that they in
turn came from still more primitive animals. This is the primary meaning
of "evolution" among biologists. "Biological evolution," according to
the National Academy' booklet, "explains that living things share common
ancestors. Over time, evolutionary change gives rise to new species. Darwin
called this process 'descent with modification,' and it remains a good
definition of biological evolution today." For Charles Darwin, descent
with modification was the origin of all living things after the first
organisms. He wrote in The Origin of Species: "I view all beings
not as special creations, but as the lineal descendants of some few beings"
that lived in the distant past. The reason living things are now so different
from each other, Darwin believed, is that they have been modified by natural
selection, or survival of the fittest: "I am convinced that Natural Selection
has been the most important, but not the exclusive, means of modification."
When proponents of Darwin's theory are responding to critics, they sometimes
claim that "evolution" means simply change over time. But this is clearly
an evasion. No rational person denies the reality of change, and we did
not need Charles Darwin to convince us of it. If "evolution" meant only
this, it would be utterly uncontroversial. Nobody believes that biological
evolution is simply change over time. Only slightly less evasive is the
statement that descent with modification occurs. Of course it does, because
all organisms within a single species are related through descent with
modification. We see this in our own families, and plant and animal breeders
see it in their work. But this still misses the point. No one doubts that
descent with modification occurs in the course of ordinary biological
reproduction. The question is whether descent with modification accounts
for the origin of new species--in fact, of every species. Like change
over time, descent with modification within a species is utterly uncontroversial.
But Darwinian evolution claims much more. In particular, it claims that
descent with modification explains the origin and diversification of all
living things. The only way anyone can determine whether this claim is
true is by comparing it with observations or experiments. Like all other
scientific theories, Darwinian evolution must be continually compared
with the evidence. If it does not fit the evidence, it must be reevaluated
or abandoned--otherwise it is not science, but myth.
Evidence for Evolution
When asked to list the evidence for Darwinian evolution, most people--including
most biologists--give the same set of examples, because all of them learned
biology from the same few textbooks. The most common examples are:
are so frequently used as evidence for Darwin's theory that most of them
have been called "icons" of evolution. Yet all of them, in one way or another,
misrepresent the truth.
- a laboratory
flask containing a simulation of the earth's primitive atmosphere, in
which electric sparks produce the chemical building-blocks of living
- the evolutionary
tree of life, reconstructed from a large and growing body of fossil
and molecular evidence;
bone structures in a bat's wing, a porpoise's flipper, a horse's leg,
and a human hand that indicate their evolutionary origin in a common
of similarities in early embryos showing that amphibians, reptiles,
birds and human beings are all descended from a fish-like animal;
a fossil bird with teeth in its jaws and claws on its wings, the missing
link between ancient reptiles and modern birds;
moths on tree trunks, showing how camouflage and predatory birds produced
the most famous example of evolution by natural selection;
finches on the Galapagos Islands, thirteen separate species that diverged
from one when natural selection produced differences in their beaks,
and that inspired Darwin to formulate his theory of evolution;
flies with an extra pair of wings, showing that genetic mutations can
provide the raw materials for evolution;
- a branching-tree
pattern of horse fossils that refutes the old-fashioned idea that evolution
was directed; and
of ape-like creatures evolving into humans, showing that we are just
animals and that our existence is merely a by-product of purposeless
Science or Myth?
Some of these icons of evolution present assumptions or hypotheses as though
they were observed facts; in Stephen Jay Gould's words, they are "incarnations
of concepts masquerading as neutral descriptions of nature." Others conceal
raging controversies among biologists that have far-reaching implications
for evolutionary theory. Worst of all, some are directly contrary to well-established
scientific evidence. Most biologists are unaware of these problems. Indeed,
most biologists work in fields far removed from evolutionary biology. Most
of what they know about evolution, they learned from biology textbooks and
the same magazine articles and television documentaries that are seen by
the general public. But the textbooks and popular presentations rely primarily
on the icons of evolution, so as far as many biologists are concerned the
icons are the evidence for evolution.
Some biologists are aware of difficulties with a particular icon because
it distorts the evidence in their own field. When they read the scientific
literature in their specialty, they can see that the icon is misleading
or downright false. But they may feel that this is just an isolated problem,
especially when they are assured that Darwin's theory is supported by overwhelming
evidence from other fields. If they believe in the fundamental correctness
of Darwinian evolution, they may set aside their misgivings about the particular
icon they know something about. On the other hand, if they voice their misgivings
they may find it difficult to gain a hearing among their colleagues, because
(as we shall see) criticizing Darwinian evolution is extremely unpopular
among English-speaking biologists. This may be why the problems with the
icons of evolution are not more widely known. And this is why many biologists
will be just as surprised as the general public to learn how serious and
widespread those problems are.
The following chapters compare the icons of evolution with published scientific
evidence, and reveal that much of what we teach about evolution is wrong.
This fact raises troubling questions about the status of Darwinian evolution.
If the icons of evolution are supposed to be our best evidence for Darwin's
theory, and all of them are false or misleading, what does that tell us
about the theory? Is it science, or myth?