Was Darwin wrong?
In the November 2004 issue of National Geographic, David Quammen answers this question with a resounding "NO. The evidence for evolution is overwhelming."
In Quammen's view, most people who reject Darwin's theory of evolution do so out of ignorance, so he proceeds to lay out some of the evidence for it. But the evidence he lays out is exaggerated, and the problems with it are ignored.
Quammen explains that Darwin's theory has two aspects: the "historical phenomenon" that all species of living things are descended from common ancestors, and "the main mechanism causing that phenomenon," which is natural selection. The evidence presented by Darwin, he continues, "mostly fell within four categories: biogeography, paleontology, embryology, and morphology."
The first category includes evidence from similar species in neighboring habitats, such as finches on the Galapagos Islands; the second includes evidence from the fossil record, such as extinct horse-like animals that preceded modern horses; and the third includes evidence from similarities in early embryos that supposedly point to their common ancestry.
All three categories are rife with problems that Quammen overlooks. For example, the Galapagos finch story is complicated by the fact that many of what were originally thought to be thirteen species are now interbreeding with each other -- even though Darwinian theory regards inability to interbreed as the distinguishing feature of separate species.
The fossil record of horses is also much more complicated than Quammen makes it out to be; actually, it looks like a tangled bush with separate branches rather than a straight line of ancestors and descendants. Even worse, Quammen ignores the Cambrian explosion, in which many of the major groups ("phyla") of animals appeared in a geologically short time with no fossil evidence of common ancestry -- a fact that Darwin himself considered a "serious" problem that "may be truly urged as a valid argument against" his theory.
Finally, embryos fail to show what Darwin thought they showed. According to Quammen, the evidence for evolution includes "revealing stages of development (echoing earlier stages of evolutionary history) that embryos pass through before birth or hatching." Darwin (as quoted by Quammen) thought "the embryo is the animal in its less modified state," a state that "reveals the structure of its progenitor." This idea -- that embryos pass through earlier stages of their evolutionary history and thereby show us their ancestors -- is a restatement of German Darwinist Ernst Haeckel's notorious "ontogeny recapitulates phylogeny," a false doctrine that knowledgeable experts discarded over a century ago.
It is actually Quammen's fourth category, morphology (i.e., anatomical shape), which Darwin himself (as quoted by Quammen) called the 'very soul' of natural history, that provides the basis for the other three. In each category, similarity in morphology ("homology") is interpreted as evidence for evolutionary relatedness. According to Darwin, features in different organisms are homologous because they were inherited from a common ancestor through a process he called "descent with modification."
The biologists who described homology a decade before Darwin, however, attributed it to construction or creation on a common archetype or design. How can one determine whether homology in living things comes from common ancestry or common design? Simply pointing to the similarities themselves won't do, as biologist Tim Berra inadvertently showed when he used different models of Corvette automobiles to illustrate descent with modification in his 1990 book, Evolution and the Myth of Creationism. Although Berra wrote that "descent with modification is overwhelmingly obvious" in Corvettes, we all know that automobile similarities are due to common design rather than common ancestry. Only by demonstrating that a Corvette can morph into another model by natural processes could someone rule out the need for a designer. Similarly, the only scientific way to demonstrate that similarities in living things are due to common ancestry would be to identify the natural mechanism that produced them. According to Darwin's theory, that mechanism is natural selection.
So the four categories of evidence on which Darwin relied to support his theory of the historical phenomenon of evolution rely, in turn, on his theory about the mechanism of evolution. But what is the evidence for Darwin's mechanism?
The principal evidence Quammen cites is antibiotic resistance. "There's no better or more immediate evidence supporting the Darwinian theory," Quammen writes, "than this process of forced transformation among our inimical germs."
Perhaps so; but then Darwin's theory is in serious trouble. Antibiotic resistance involves only minor changes within existing species. In plants and animals, such changes had been known for centuries before Darwin. Nobody doubts that they can occur, or that they can be produced by selection. But Darwin claimed much more, namely, that the process of selection could produce new species -- indeed, all species after the first. That's why Darwin titled his magnum opus The Origin of Species, not How Existing Species Change Over Time.
Yet no one has ever observed the origin of a new species by selection, natural or otherwise. Bacteria should be the easiest organisms in which to observe this, because bacteria can produce thousands of generations in a matter of months, and they can be subjected to powerful mutation-causing agents and intense selection. Nevertheless, in over a century of research no new species of bacteria have emerged. Quammen cites Darwinian biologists who claim to have produced "incipient species," but this merely refers to different strains of the same species that the researchers believe -- on theoretical grounds -- might eventually become new species. When the truth of the theory itself is at stake, such a theoretical extrapolation hardly constitutes "overwhelming evidence" for it.
So the evidence Quammen presents for Darwin's theory falls far short of confirming it. Biogeography, paleontology, embryology and morphology all rely on homologies, and the only way to determine whether homologies are due to common descent rather than common design is to provide a natural mechanism. Yet Darwin's mechanism, natural selection, has never been observed to produce a single new species. Scientific theories (Quammen acknowledges) should not be accepted as a matter of faith, but only on the basis of evidence. And given the evidence, any rational person is justified in doubting the truth of Darwin's theory.
As Quammen points out at the beginning of his article, public opinion polls conducted over the past twenty years have consistently shown that only about 12% of Americans accept Darwin's theory that "humans evolved from other life-forms without any involvement of a god." The reference to "god" is significant, because it shows that science is not the only thing at stake here: Darwinism also makes religious and philosophical claims. Most importantly, Darwinism is committed to naturalism, the philosophy that nature is all that exists and God is imaginary -- or at least unnecessary. It is not surprising, then, that many people reject Darwinism on religious grounds. Nevertheless, Quammen maintains, most Americans are antievolutionists only because of "confusion and ignorance," because "they have never taken a biology course that deals with evolution nor read a book in which the theory was lucidly described."
As someone with a Berkeley Ph.D. in biology, I dispute Quammen's characterization of Darwin's doubters as confused and ignorant. On the contrary, Quammen's article makes it abundantly clear why it is quite reasonable to doubt Darwinism: The evidence for it is "underwhelming," at best.
The No Child Left Behind Act of 2001 requires every state to formulate standards for science education. As a guide to interpreting the law, Congress also passed a Conference Report recognizing "that a quality science education should prepare students to distinguish the data and testable theories of science from religious or philosophical claims that are made in the name of science. Where topics are taught that may generate controversy (such as biological evolution), the curriculum should help students to understand the full range of scientific views that exist, why such topics may generate controversy, and how scientific discoveries can profoundly affect society.''
In other words, students should be encouraged to distinguish the actual evidence for Darwin's theory from the naturalistic philosophy that accompanies it. Furthermore, students should be taught not only the evidence for the theory, but also why much of that evidence is controversial. Congress recommends this; the American people overwhelmingly support it; and good science demands it.
Quammen claims that evolution is "more crucial nowadays to human welfare, to medical science, and to our understanding of the world, than ever before." Yet no country in history has made more contributions to human welfare and medical science than America. Is it just a coincidence that the vast majority of citizens in the most scientifically successful nation on Earth are skeptical of Darwin's theory? I think not. As a scientist myself, it seems to me that a healthy skepticism is essential to good science. This caveat applies to all theories, including Darwin's.
If Quammen's article had accurately presented not only the evidence for Darwin's theory, but also the problems with that evidence, it might have made a valuable contribution to scientific literacy in America. As it stands, however, the article is nothing more than a beautifully illustrated propaganda piece. The readers of National Geographic deserve better.
Jonathan Wells, Ph.D.
Senior Fellow, Center for Science and Culture