Last year was the 200th anniversary of the birth of Charles Darwin and the 150th anniversary of the publication of his book, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. The anniversary was marked by conferences the world over. I will not tell you how many I attended; ecologically sensitive readers of The Chronicle might start whining about carbon footprints and that sort of thing. Let me just say that I found myself going no fewer than three times through the Quad City International Airport, in Moline, Ill. Moline!
I mention this as background to the publication of a new book by Jerry A. Fodor, a professor of philosophy at Rutgers University, and Massimo Piattelli-Palmarini, a professor of cognitive science at the University of Arizona. The title of the book, What Darwin Got Wrong (Farrar, Straus and Giroux), tells you their opinion of the old English naturalist and of his theory of evolution through natural selection. If Fodor and Piattelli-Palmarini were an isolated case, one could dismiss their book with a grimace (if you were a biologist), or welcome them with a cheer (if you were a creationist). But in the philosophical community, there is an increasingly vocal cadre of eminent philosophers harboring doubts about Darwin. To understand their critique, we must first put the clock back a year, to the beginning of the celebrations.
The anniversary conferences usually had a smattering of professional Darwin types like me—I am a historian and philosopher of science specializing in evolutionary theory—but the bulk of the presenters and attendees were evolutionary biologists. For two reasons, the atmosphere was universally positive. First, scientists deeply respect Darwin and his achievements. These people are evolutionists—they take the past seriously. Second, there was not a person at these conferences who was not excited about the science today. Evolutionary biology is on a roll, and that was a cause for celebration—and frenetic presentations that jammed in as much new science as possible. Moreover, to a person, the scientists saw that the first point led smoothly into the second. Everyone appreciates the tools of Darwinism, above all the mechanism of natural selection. But great science doesn't stand still. It picks up and carries ideas and findings way beyond the wildest hopes of its founders. Evolutionary biology today is deeply Darwinian, but it has outpaced the Origin in ways that its author could never have imagined. To use a hackneyed phrase, Darwin gave biology a paradigm, and biologists have been expanding it ever since.
Here is some of the work I heard about. This is important for what I have to say in this essay. Peter and Rosemary Grant, emeritus professors of biology at Princeton University, have for many years been tracking and studying the finches of the Galápagos archipelago. The Grants have recently become more interested in speciation, when groups pull apart and set up reproductive barriers. Paleoanthropologists like Dean Falk, my colleague at Florida State University, have been studying the brain of the humanlike little beings recently discovered in the Indonesian archipelago, Homo floresiensis, better known as the hobbit. I also several times heard Donald Johanson, director of the Institute of Human Origins at Arizona State University, who, in 1974, discovered Lucy, a three-million-year-old female hominid skeleton. She walked upright yet had a brain the size of a chimpanzee's. The buzz now is about the reconstructed Ardipithecus ramidus. Older than Lucy by about a million years, she, too, walked upright. She still lived a lot of the time in the trees, hence challenges earlier hypotheses about proto-humans moving out to the plains as the jungles dried up, and then needing to stand upright. Bipedalism came while we were still in the jungle.
Sean Carroll, a biologist at the University of Wisconsin at Madison and a master of evolutionary development ("evo devo"), and his team are turning up fantastic findings about how genes regulate development. The most exciting discovery in recent evolutionary biology is that humans and fruit flies, Drosophila, are remarkably similar at the molecular level, like DNA. Organisms really are built on the Lego principle, with the same building blocks: Go one way and get a human, another way and get a fly. Meanwhile evolutionary psychologists and anthropologists like Marc Hauser, at Harvard University, are studying moral behavior with such precision that they are able to pinpoint the parts of the brain involved in ration-al thinking, emotional reactions, and motivations. And, as always, the context is Darwinian. Why did natural selection push things this way rather than some other way?
Exciting times, which makes it all the more remarkable to hear voices from within the mainstream of philosophy questioning the veracity of evolutionary theory. I'll mention three. First there is Alvin Plantinga. Although he teaches at the University of Notre Dame, a Roman Catholic institution, Plantinga is North America's most distinguished Protestant philosopher of religion. A deeply sincere Calvinist, he has never hesitated to argue for his faith and has done groundbreaking work on questions of knowledge and belief. Even if you disagree with his conclusions, you can admire his skill and learn from his arguments. Plantinga, however, has long harbored a distrust, even an ardent dislike, of evolutionary theorizing in general and of Darwinian thinking in particular. In an essay published in 1999, he wrote, "Consider the role played by evolutionary theory in our intellectual world. Evolution is a modern idol of the tribe; it is a shibboleth distinguishing the ignorant fundamentalist goats from the informed and scientifically acquiescent sheep. Doubts about it may lose you your job. It is loudly declared to be absolutely certain, as certain as that the earth rotates on its axis and revolves around the sun—when it is no such thing at all."
Plantinga is an open enthusiast of intelligent design, the belief that at some points in life's history an intelligent being intervened to move the process along. I am not quite sure whether this makes him a full-blooded creationist, although he has in the past said he does not think it an impossible position. Some supporters of intelligent design, like Phillip E. Johnson, an emeritus professor of law at the University of California at Berkeley and author of Darwin on Trial (Regnery, 1991), seem to reject all forms of evolution. Others, like Michael J. Behe, a professor of biological sciences at Lehigh University and author of Darwin's Black Box: The Biochemical Challenge to Evolution (Free Press, 1996), seem to accept a lot of common descent and might even be called theistic evolutionists, meaning that they think God guides the course of continuous development. Wherever Plantinga stands on this spectrum, he stands with the intelligent-design theorists in strongly emphasizing what they see as the falsity of Darwinian evolutionary biology.
Why does Plantinga feel this way? In his view, Darwinism implies that there is and can be no direction in life's history. All change is a function of randomly appearing new variations (mutations) that are then sifted by the opportunistic mechanism of natural selection. Although new variations are not uncaused, they do not appear according to need. As Darwin himself argued, to think otherwise is to illicitly bring in a directing God. The late Harvard paleontologist Stephen Jay Gould used to pun that the arrival of the human species was entirely an accident brought on by our lucky stars—a comet that hit the earth 65 million years ago, wiping out the dinosaurs and allowing for the rise of mammals. It is precisely that kind of thinking to which Plantinga is opposed.
Plantinga's reactions to evolutionary biology are disappointing but understandable. Disappointing because, generally speaking, Calvinists are favorable to science: It is all part of God's sovereignty, and it is our task to discover his immutable laws. As the Victorians used to say about sexual intercourse, if God decided that we should reproduce in such a disgusting way, then it is for us to accept this fact and put it in context. The same can be said about Darwinian evolution. Plantinga's views are understandable because philosophy today tends to be very secular, and there is a lot of sympathy for the claims of the so-called New Atheists—Richard Dawkins, Daniel C. Dennett, Sam Harris, Christopher Hitchens—that if you are a Darwinian, then you ought to be at least an agnostic, if not an outright atheist. Philip Kitcher, a professor of philosophy at Columbia University and author of Living With Darwin: Evolution, Design, and the Future of Faith (Oxford University Press, 2007), has spoken of Plantinga's decision to blurb Johnson's book as revealing "a combination of Schwärmerei [excessive sentiment] for creationist doctrine and profound ignorance of relevant bits of biology," which has caused Plantinga to put his brain "in cold storage."
Much more surprising is the position of the New York University philosopher Thomas Nagel, who has established himself right at the top of the field thanks to a long series of dazzling essays on topics as diverse as the thinking apparatus of a bat and the nature of sexual perversion. Although he states firmly that he does not believe in a deity, he has now come out against Darwinism. If Nagel is not a supporter of intelligent design, one wonders why he says what he does. He has endorsed a book by Stephen C. Meyer, Signature in the Cell: DNA and the Evidence for Intelligent Design (HarperOne, 2009), naming it one of the top books of 2009 in the Times Literary Supplement.
In a recent article, Nagel argues that it is proper to teach intelligent design in the classroom. Doubting the Darwinian claim that the sources of variation are undirected, Nagel quotes Behe as an authority. "Are the sources of genetic variation uniformly random or not? That is the central issue, and the point of entry for defenders of ID," Nagel writes. He goes on to tell us that Behe's recent book, The Edge of Evolution, examines the "currently available evidence about the normal frequency and biochemical character of random mutations in the genetic material of several organisms."
Nagel leaves the reader with the impression that Behe's concerns are well taken. Behe, according to Nagel, argues that "widely cited examples of evolutionary adaptation, including the development of immunity to antibiotics, when properly understood, cannot be extrapolated to explain the formation of complex new biological systems. These, he claims, would require mutations of a completely different order, mutations whose random probability, either as simultaneous multiple mutations or as sequences of separately adaptive individual mutations, is vanishingly small."
Like Plantinga, Nagel is skeptical about the whole evolutionary enterprise. Suppose someone says that doubting evolutionary theory is equivalent to thinking the earth is flat. Nagel writes: "This seems to me, as an outsider, a vast underestimation of how much we do not know, and how much about the evolutionary process remains speculative and sketchy." He goes on to tell us that those who think we are now well on the track to understanding the mechanisms of evolution are wrong: "Nothing close to this has been done." And in a comment to which I shall refer below, he writes: "A great deal depends on the likelihood that the complex chemical systems we observe arose through a sufficiently long sequence of random mutations in DNA, each of which enhanced fitness. It is difficult to find in the accessible literature the grounds for evolutionary biologists' confidence about this."
Naturally the origin-of-life issue is raised—and found wanting ("a complete scientific mystery at this point"). It is hardly surprising, therefore, that Nagel thinks that evolutionary biology is more happily accepted by nonbelievers than by theists: "This is just common sense."
Jerry Fodor, no less distinguished than Nagel and Plantinga, is well known for his claim that the mind is composed of separately functioning modules. And he, too, has taken to criticizing Darwinian theory, first in an article in the London Review of Books and now in What Darwin Got Wrong. Fodor finds something deeply flawed in contemporary evolutionary thinking: "An appreciable number of perfectly reasonable biologists are coming to think that the theory of natural selection can no longer be taken for granted. This is, so far, mostly straws in the wind; but it's not out of the question that a scientific revolution—no less than a major revision of evolutionary theory—is in the offing."
To Fodor the notion of natural selection is flawed. He has long been on record arguing that metaphors in science are misleading, and that they must be eliminated as science matures. In the case of Darwinism, we have an analogy or metaphor at work, between the artificial selection that breeders use when they improve livestock—shaggier sheep, beefier cows—and the process of differential reproduction that Darwinians think leads to evolutionary change (in the direction of adaptive advantage). Fodor believes that differential reproduction illicitly brings mind into the natural process:
The present worry is that the explication of natural selection by appeal to selective breeding is seriously misleading, and that it thoroughly misled Darwin. Because breeders have minds, there's a fact of the matter about what traits they breed for; if you want to know, just ask them. Natural selection, by contrast, is mindless; it acts without malice aforethought. That strains the analogy between natural selection and breeding, perhaps to the breaking point. What, then, is the intended interpretation when one speaks of natural selection? The question is wide open as of this writing.
Fodor argues that this problem is insoluble. Fortunately we need not worry much, because in going with selection, evolutionists have been grasping the wrong end of the stick. In his view, today's proper-thinking evolutionary biologists are finding that it is all in the variations anyway. All evolutionary change comes about through the genes and their development. Even if natural selection were at work, Fodor argues, the most it could do is clean up afterward.
What does one say about these critics? One could certainly pick apart individual things, for instance Fodor's claims about selective breeding versus natural selection. The very last thing that Darwin and his followers are trying to do is put mind into nature. In both artifice and nature, some organisms are going to reproduce and others are not, and the reasons for that are (on average) going to be connected to the different features of the winners and losers. To say that a speckled moth is less likely to be eaten by a robin than a dark moth, because the robin can less easily see the speckled moth against the lichen-covered tree, is to say nothing about God or any other conscious being.
One could also pick up on the fact that neither Plantinga nor Nagel seems to have the slightest awareness of the scientific criticisms that have been launched against intelligent design. Every example that supporters of intelligent design produce to suggest that natural causes are not adequate—the bacterial flagellum, the blood-clotting cascade—has been shown to be the exquisite end result of evolution. And one could certainly groan at the tired suggestion that Darwinians are unaware of or threatened by developments in evolutionary development. No evolutionary biologist, least of all Sean Carroll, suggests that one day the eye just appeared. However the new sources of variation play out, selection is going to be there right along with them.
But rather than work over the details, I want to draw attention to the way this crop of critics ignores evolutionary biology—aside from the kind of cherry-picking in which Fodor engages. Nagel may sneer about the failure to find "accessible literature" that answers his worries. In what part of the library was he doing his literature search? Where, for example, is any discussion of the Grants' work on the Galápagos finches? What about a detailed look at the new scholarship that is challenging earlier thinking about the evolution of bipedalism? What about the discoveries of molecular biology and of the similarities (homologies) between humans and fruit flies? And why no mention of Marc Hauser and his work uncovering the secrets of moral thinking? There is a deafening silence on those and other issues. Fodor, Nagel, and Plantinga don't need to turn themselves into biochemists, but some awareness of the issues and advances would not be entirely misplaced.
This total lack of interest in the science is surely suggestive. The critics are being driven by other, for them deeper, concerns. And as an evolutionist, I turn to the past for clues. What fueled the initial opposition to Darwin was a concern with our species, with Homo sapiens. For 150 years, since the Origin, critics have feared that we humans might become part of the evolutionary picture—not just our bodies, but our minds, our very souls. What makes us distinctively and uniquely human? This worry is still alive and well in today's philosophical community. Plantinga is open in his fear that Darwinism makes impossible the guaranteed existence of our species. More, for years he has argued that Darwinism is bound up with the metaphysical belief that everything is natural (as opposed to supernatural), and that this leads to a collapse of rational belief and knowledge. The chance elements in Darwinism are simply not compatible with Plantinga's Christian faith.
As nonbelievers, Nagel and Fodor are a bit different, but not that different. For years Nagel has argued against a reductive view of the human mind, believing it to be more than just molecules in motion—the obvious end result of Darwinism. At some level, Nagel believes, the mind is above the material. It is perhaps a stretch, but probably not too much of a stretch, to say that the kind of sympathetic attitude that Nagel takes toward intelligent design points not so much to a concealed theism (akin to Plantinga's open theism) as to a kind of vitalism, in which there are nonnatural, nonphysical forces that direct things in the material world.
And then there is Fodor. The final section of his new book is very revealing. As a dreadful warning to those who do not accept his main conclusions, Fodor prints passage after passage of claims by Darwinians that one can understand human nature and thinking as the product of natural selection: This is where we will all end up if we don't stop the rot right now. My suspicion is that Fodor doesn't really give a damn about fruit flies or finches or anything else out there. But when it comes to Homo sapiens, he wants no part of a naturalistic explanation that reduces design to the workings of blind law. There may not be a God, but we sure are made in his image.
I often joke, as one who spends a lot of time fighting creationists, that when one of them says something silly, that means more work for me: bread on the table. When one of them says something really silly, there is strawberry jam, too. In 2005, after a trial in Dover, Pa., a federal judge ruled that intelligent design should not be taught in schools. Pat Robertson's response—"God is tolerant and loving, but we can't keep sticking our finger in his eye forever. If they have future problems in Dover, I recommend they call on Charles Darwin. Maybe he can help them"—kept me and my family well fed for weeks.
Now those of us who love Darwin and his theory have got the philosophers to deal with, too. I see steak in my future. But in truth, I am not really happy. I might even turn vegetarian if I could persuade my fellow philosophers to start taking science seriously. Could they possibly entertain the idea that being at one with the living world does not make us any less worthy as human beings? After the Origin was published, the wife of the Bishop of Worcester supposedly reacted: "Descended from monkeys? Let us hope that it is not true. But if it is true, let us hope that it not become widely known."
A century and a half later, the time has come to shout the truth from the rooftops.