Why Darwin Matters

by Michael Shermer

  1. The Miller-Urey Experiment, which demonstrates the chemical origins of the building blocks of life.

  2. Darwin’s Tree of Life, which shows that all living organisms come from a common ancestor.

  3. Homology in Vertebrate Limbs, such as the similar bone structure of the forelimb of humans, bats, and whales, as examples of common ancestry and descent with modification of basic body plans.

  4. Haeckel’s Embryo Drawings, or “ontogeny recapitulates phylogeny,” showing how in their embryological development (ontogeny) organisms go through similar stages in evolutionary (phylogeny) development.

  5. Archaeopteryx, one of the best transitional fossils between dinosaurs and modern birds that demonstrates the evolution of flight.

  6. Peppered Moths, which demonstrate how natural selection works by eliminating solid-colored moths that stand out on mottled tree bark, allowing the camouflaged peppered moths to survive and reproduce.

  7. Darwin’s Finches, which serve as examples of how speciation happens in nature.

  8. Four-Winged Fruit Flies, which demonstrate how a change in a single gene can produce dramatic morphological and physical changes.

  9. Fossil Horses and Directed Evolution, as examples of well-documented evolutionary pathways from simple to complex.

  10. From Ape to Human, demonstrating the “missing links” between apes and humans.

  When these are presented as examples of evolution, Wells argues, “students and the public are being systematically misinformed about the evidence for evolution.” None of them is true, says Wells, and by easily refuting them, Intelligent Design creationists hope to bring down the entire evolutionary edifice.

  First, the old creationists’ saw that mistakes in science are a sign of weakness is a gross misunderstanding of the nature of science, which is constantly building upon both the mistakes and the successes of the past. Science does not just change, it builds cumulatively on the past. Scientists make mistakes aplenty, and in fact this is how science progresses. The self-correcting feature of the scientific method is one of its most powerful assets. Hoaxes like Piltdown Man and honest mistakes like Nebraska Man, Calaveras Man, and Hesperopithecus are in time exposed. In fact, it was not creationists who exposed these errors, it was scientists who did so. Creationists simply read about the scientific exposés of these errors, and then duplicitously advanced them as their own.

  Intelligent Design theorists do the same thing, trolling through scientific journals and books in search of exposures by scientists of errors by other scientists and claiming them as the results of Intelligent Design research. This is what happened in the case of Wells’s “punctured” icons of the peppered moths and Haeckel’s embryo drawings. In the 1950s, the British evolutionary biologist Bernard Kettlewell correlated the evolution of darker forms of certain moths in England with industrial pollution—darker moths were better camouflaged on darker trees—and noted the reverse with the lightening of trees after clean air acts were passed (lighter moths were better camouflaged on lighter trees). But as later scientists noted, peppered moths do not rest on trees; although Kettlewell’s recording of the changing coloration of peppered moths was accurate, his placing of them on trees was staged for photographic purposes and he was later nailed for it by scientists. In the case of Haeckel’s embryological drawings, they were revealed to be fraudulent first in a technical scientific paper in the prestigious journal Nature, and then publicly by Stephen Jay Gould in his popular Natural History column.53

  Next: Make that nine icons of evolution. The first icon Wells lists deals with the chemical origins of life, which is not generally considered a part of evolutionary theory. In any case, the science of life’s origin has come a long way since Miller and Urey’s experiments in the 1950s, so it is doubly disingenuous to focus on these primitive incipient research protocols.

  Further, despite the high improbability of finding fossils, we have now a reasonably rich record of the history of life from the earliest bacteria fossils of 3.8 billion years ago, to the simple single-celled bacteria 3.5 billion years ago, to fossil archaebacteria 2.9 billion years ago, to the first eukaryotic cells about 2.5 billion years ago, to multicellular eukaryotic fossils 1.7 billion years ago, to fossils of higher algae forms 1.2 billion years ago, to the Ediacaran fauna 650 million years ago, all of which led to the so-called Cambrian “explosion” of about 550 to 500 million years ago. In highlighting this “explosion” as lacking any ancestral history (and therefore claiming it as proof that an Intelligent Designer miraculously sparked the creation of life), Intelligent Design advocates conveniently ignore three billion years of evidence of life’s gradual evolution.

  For each of these icons, Intelligent Design theorists also fail to provide an alternative theory to account for the data. For example, homology in vertebrate limbs has a perfectly sound evolutionary explanation: The skeletal structure of humans, bats, and whales is similar because we have similar ancestry—evolution created one basic architectural design from which natural selection shaped the wide variety of types. But even if this is wrong, as Wells says, what is the Intelligent Design explanation for homologies? Why would an Intelligent Designer design a whale’s flipper to have precisely the same set of bones as a human arm and a bat’s wing? And why would the ID make a bat’s wing different from a bird’s wing and an insect’s wing? Evolution’s answer is that a bat is a mammal with a different evolutionary lineage than birds and insects. What answer do Wells and the other Intelligent Design advocates offer?

  Finally, there is the underlying assumption that the theory of evolution is founded on these ten icons, and thus that debunking them refutes the theory at large. Not so. The theory of evolution is proved through the convergence of evidence from thousands of lines of inquiry from diverse fields of study quite apart from this list. The vast bulk of data supporting evolution dwarfs these ten examples.

  That’s the best science the Intelligent Design movement has to offer—lots of miracles, a handful of equations, and ten straw examples set against thousands of compelling lines of inquiry. But as often as not, science is not under debate; it is under attack. For example, in my debate at the University of California, Irvine, the Young Earth creationist Kent Hovind announced as his opening statement, “I am here to win you over to Christ. And I’m here to win Michael Shermer over to Christ.”

  With that statement, Hovind lost the debate. He was not there to debate evolution versus creation or natural versus supernatural design. He was there to witness for the Lord. Everything he said from there on was irrelevant or wrong: Dogs come only from dogs. Variations do not lead to new species. Design implies a Designer. There is an afterlife. The Bible is literally true in everything it says. Humans used to live nine hundred years. There is no right and wrong without God. Noah’s flood explains geological formations and species distribution. Dinosaurs and humans lived simultaneously, dinosaurs on the Ark were very young and small, and dinosaurs that were large (“behemoth” and “leviathan” in the Bible) drowned in the flood. Radiometric dating is unreliable. Jesus said the universe is young. The theory of evolution is a religion that leads to atheism, abortion, and communism. Evolutionists are liars. Scientists are arrogant (they call themselves “Brights”!). Creationists are not allowed to publish in scientific journals. Creationism is censored from public schools. Microevolution may be true, but macroevolution, organic evolution, stellar evolution, chemical evolution, and cosmic evolution are all lies perpetrated by the lying liars who worship at the faux religion of evolution. And, of course, Jesus died for our sins.

  This is what the evolution-creation debate is really about—religion, not science—and Intelligent Design theorists should be rightly called Intelligent Design creationists to drive the point home. Science is what scientists do, and Intelligent Design Creationists are not doing science. They are doing religion. It is not coincidental that almost all Intelligent Design creationists are Christians. But I will grant them this: Intelligent Design arguments are reas
ons to believe if you already believe. If you are not a True Believer, if you are a skeptic or a Fence Sitter, creationism and Intelligent Design are untenable.

  Can any good come out of such debates? I think so. Outside heretics can stimulate us to refine our arguments and improve our explanatory prose. As Isaac Asimov once observed in confronting what he called exoheresies, or outside challenges to the status quo (in this case the radical ideas of Immanuel Velikovsky):

  An exoheresy may cause scientists to bestir themselves for the purposes of reexamining the bases of their beliefs, even if only to gather firm and logical reasons for the rejection of the exoheresy—and that is good.54

  Yet, there is a final question that would chill Asimov’s blood: Will those who accept evolution let those who do not accept it determine what science is?

  SCIENCE UNDER ATTACK

  How do we look for a new law? First, we guess it. Don’t laugh. That’s really true. Then we compute the consequences of the guess to see what it implies. Then we compare those computation results to nature—or to experiment, or to experience, or to observation—to see if it works. If it disagrees with experiment, it is wrong. In that simple statement is the key to science. It doesn’t make any difference how beautiful your guess is, how smart you are, who made the guess, or what his name is. If it disagrees with experiment, it’s wrong. That’s all there is to it.

  —Richard Feynman, lecture at Cornell University on the nature of science, 1964

  So much comes down to necessity and chance.

  In the 1990s I published a series of articles in respected peer-reviewed journals applying chaos and complexity theory to human history.1 Out of that research I constructed a theoretical model demonstrating the relative roles of necessity and contingency—law and chance—in history, and how the relationship of these two factors helps to explain why sometimes the kingdom is lost for the want of a horseshoe nail while at other times a million horseshoe nails would have made no difference at all. Sometimes “great men” make history; at other times geographical conditions, social circumstances, economic forces, and political machinations swamp any influence that individuals may have. I even published a book with one of the top university presses in which I demonstrated how my theory helps to explain such world-shaping events as the Holocaust.2 I had high hopes that historians would adopt my theory, put it into practice, and perhaps even teach it to their students. They haven’t. Maybe I did not communicate my theory clearly. Possibly historians do not use such theoretical models. Worse, perhaps my theory is wrong or useless. Should I appear before Congress to demand that legislation be passed to give my theory equal time with other theories of history? Should I lobby school board members to force history teachers to teach my theory of history?

  The God of the Government

  Since Intelligent Design theory has failed to win the debate on scientific merit, or to convince scientists to accept its ideas as providing some useful insight into evolution and the structure of life, many of its proponents are taking their case to the government. If they cannot get the scientists to believe in their ideas, they will legislate their ideas into the classroom. The reasoning is rather straightforward:

  1. Scientists do not accept Intelligent Design as science.

  2. Therefore Intelligent Design is not taught in public school science classes.

  3. I think Intelligent Design is science.

  4. Therefore I will lobby the government to force teachers to teach Intelligent Design as science.

  This is what I call the God of the Government argument (pace the God of the Gaps argument discussed in the last chapter): If you can’t persuade teachers to teach your idea based on its own merits, see if you can get the government to force teachers to teach it. If I were trying to force my theory of history into public school history classes, my actions would be considered ludicrous. It is just as absurd when Intelligent Design theorists push their way into science lesson plans. In the free marketplace of ideas, turning to the government to force your theory on others—particularly children—goes against every principle of liberty upon which modern Western democracies are founded. It seems, however, that science might not fall under such moral principles of liberty—unless we fight for it.

  If I were a religious believer, I would be embarrassed by the latest round of attempts to legislate these beliefs into the public schools. If creationists want their doctrines taught in public school science classes, they need first to develop a science, and then to convince scientists that their scientific ideas merit inclusion based on the quality of the arguments and evidence.

  How Science Makes It into

  Science Textbooks and Classrooms

  Since we live in a free society, parents are free to choose whatever schools they want their children to attend, or even to homeschool their children if they are dissatisfied with the choice of public and private schools in their area. If all schools were private, and if the education of children were strictly a function of the free market, there would be no high-profile court cases and school board battles over evolution and creationism; there would be no debate over evolution and Intelligent Design. Creationist parents would be free to send their kids to private schools where creationism is taught. Indeed, some creationist parents do this now (or they opt for homeschooling programs that include a creationist unit in the biology curriculum).

  Conflict arises out of the fact that public schools are funded by the government, and since we are the government, taxpayers feel that they should have some say in what is taught in public schools. This sounds like a reasonable argument, until we carry it to its logical conclusion—all parents would be justified in demanding equal time for their particular religious, political, or social beliefs. Christians would want a Christian slant in the curriculum, Muslims would want a Muslim slant, Native Americans a Native American slant, and so forth. Education would dissolve into an endless parade of beliefs given equal time, with no core curriculum on which to focus students’ attention. (To get just a flavor of exactly what that “so forth” would entail, visit the appendix.)

  So how does a new scientific discovery or theory make it into the science curriculum? It usually takes a long time, because science is a fairly conservative institution with high and exacting standards of evidence. It is typically years before experimental results trickle down from scientific conferences and journals into textbooks and lecture notes; and it is often decades before a new theory displaces an existing and commonly taught theory. Scientists face these hurdles all the time. The case of the microbiologist Lynn Margulis is instructive.

  Lynn Margulis is best known for her theory of symbiogenesis, which challenges the tenet that inherited variation comes primarily from random mutations. Rather, Margulis argues, new species, at least microbial species, evolve through the exchange of genomes, where the fusion of genomes in symbioses leads to the variation on which natural selection acts, which then leads to increasing complexity in the species. She first published her theory in 1970. For more than three decades she has been lecturing on it at scientific conferences, writing about it in hundreds of articles in peer-reviewed scientific journals, expanding upon it in technical books published by peer-reviewed university presses, and elaborating on it in popular books published by trade presses. After all this effort and evidence, the theory of symbiogenesis is finally wending its way into the generally accepted body of evolutionary knowledge taught to students, even though it remains controversial in some scientific circles.3 If Intelligent Design creationists want to know how to get their theory taught in public schools, they should take a lesson from Lynn Margulis: Roll up your sleeves and get to work—lab and field work, not legislative lobby work.

  This vetting process by the community of scientists in a field is how new discoveries and theories gain acceptance or experience rejection. Adjudication is determined by a vote of sorts—the scientists in a field vote with their feet, either by running back to their labs to test the new discovery or theory, or by dis
carding it altogether. If it is useful, it stands a good chance of finding its way into general textbooks, which are often written by members of that scientific community. This system sounds insular, but it is remarkably egalitarian and democratic because anyone can join in the process, as long as they abide by the rules of the game of science. The Intelligent Design theorists, rather than respect these rules, instead revert to the question, What is science?

  Science Defined in Its Defense

  Creationists sometimes claim that the theory of evolution is a doctrine in a religion they call Secular Humanism, and thus if creationism is not taught in public schools, then neither should evolution be. The vast majority of believers and theists around the world fully accept the theory of evolution, so clearly they are not mutually exclusive. But is the theory of evolution a religious belief? No, it is not.

  If a branch of science like evolutionary theory is a tenet of religion, then the definition of religion is so sweeping that virtually everything is a religion, rendering the word meaningless. Science is not a religion. Science is a very specific branch of human knowledge with a set of methods quite distinct from other branches of knowledge. I have, in earlier chapters, pragmatically defined it this way: Science is a testable body of knowledge open to rejection or confirmation. More formally, I have defined it as follows: