Saturday, March 13, 2010

What Darwin's Doubters Get Wrong

Michael Ruse remarks on a new book, What Darwin Got Wrong by Jerry A. Fodor. His piece, in the Chronical of Higher Education, is titled: What Darwin's Doubters Get Wrong.

...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...

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.

... 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....

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. ... 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.
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New York University philosopher Thomas Nagel ... 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.

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."...
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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.
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.
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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 Gal├ípagos 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?
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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.

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