Monday, June 11, 2007

Yet One More Post on Brownback and Evloution

I know, I am beating a dead horse with yet another post on Sam Brownback's op-ed on evolution, but Jerry Coyne, a professor in the department of ecology and evolution at the University of Chicago, has written a wonderful response to that op-ed that is well worth a read. Here are highlights, but do read it all:

Senator Brownback showed this poisonous mixture of scientific ignorance and religious dogmatism in a May 31 op-ed piece in The New York Times ("What I Think About Evolution"), written to clarify why he raised his hand to dissent from Darwinism. The first thing that's clear is that Brownback displays a fundamental misunderstanding of evolutionary biology. He claims that there is "no one single theory of evolution," citing punctuated equilibrium as an alternative to Darwinism. (He's apparently implying that there might be something dubious about evolution because there's a multiplicity of theories).

Well, he is wrong here for two reasons. First, the hypothesis of punctuated equilibrium is no longer widely accepted, and second (as its proponent Stephen Jay Gould repeatedly averred), it was conceived as an expansion of Darwinism, not an alternative to it. There is only one going theory of evolution, and it is this: organisms evolved gradually over time and split into different species, and the main engine of evolutionary change was natural selection. Sure, some details of these processes are unsettled, but there is no argument among biologists about the main claims.

Brownback also presents the familiar creationist misrepresentation of evolution as a chance process, claiming that "man . . . is merely the chance product of random mutations." He doesn't seem to know that while mutations occur by chance, natural selection, which builds complex bodies by saving the most adaptive mutations, emphatically does not. Like all species, man is a product of both chance and lawfulness.

Lifting another claim from the creationist handbook, Brownback limits the ability of evolution to making only "the small changes that take place within a species." That's just false. Yes, evolution makes small changes, but over time they add up to big ones. As the old proverb goes, take care of the pennies and the pounds will take care of themselves. The evolution of amphibians from fish, reptiles from amphibians, birds from reptiles, and humans from apelike ancestors—all of these are amply documented in the fossil record. For decades, creationists have lovingly perpetuated this myth, that evolution can make small changes but not big ones, oblivious to the mounting evidence, not just from the fossil record, but from genetics, biogeography, embryology, and geology.

. . .

Brownback's misunderstanding of science is more dangerous than his ignorance of evolution, and should be disconcerting to educators and parents hoping to see their children educated properly. He rejects evolution if "it means assenting to an exclusively materialistic, deterministic vision of the world that holds no place for a guiding intelligence." Using that criterion he'd have to reject all of science, including physics and chemistry!

Science simply doesn't deal with hypotheses about a guiding intelligence, or supernatural phenomena like miracles, because science is the search for rational explanations of natural phenomena. We don't reject the supernatural merely because we have an overweening philosophical commitment to materialism; we reject it because entertaining the supernatural has never helped us understand the natural world. Alchemy, faith healing, astrology, creationism—none of these perspectives has advanced our understanding of nature by one iota. So Brownback's proposal to bring faith to the table of science is misguided: "As science continues to explore the details of man's origin, faith can do its part as well." What part? Where are faith's testable predictions or falsifiable hypotheses about human origins?

Brownback's ill-conceived accommodationism between science and faith extends to the notion of truth itself. He accepts the common view that "science seeks to discover the truths about the nature of the created order and how it operates, whereas faith deals with spiritual truths." Nearly all scientists would object to the word "created" in this sentence, but in any case it's doubtful whether any "truth" (in the sense of something that conforms to fact) can be gained through spirituality alone.

Scientific truths are facts agreed on by all observers using scientific methods. The formula for water is H2O, the Earth is 4.6 billion years old, and the speed of light is 186,000 miles per second. These are matters that can be verified empirically by any scientist, be she Muslim, Catholic, or Hindu.

But what is "spiritual truth"? It is simply what someone believes to be true, without any need for evidence. One man's spiritual truth is another man's spiritual lie. Jesus may be the son of God to Christians, but not to Muslims. The Inuit creation story begins with a pair of giants who chopped off their daughter's fingers, which became seals, whales, walrus, and salmon. There have been thousands of religions, and thousands of religious "spiritual truths," but many of them conflict with each other, and some of them conflict with science.

Many Americans, for example, have been taught by their religion to believe that the world is less than 10,000 years old. The Inuits are wrong too: whales didn't come from detached digits but from land mammals. And those "spiritual truths" that aren't palpably false are systematically immune to challenge or rational investigation. There is simply no way to find out of them is really "true", just as we can't know which religion, if any, is "true". Is there any need, then, to speak of spiritual truths? Shouldn't we just call them "beliefs based on faith alone?" When "faith does its part," then, what does it contribute to our understanding of the way things are?

Whether he knows it or not, Brownback's forthright declarations, denying any possibility that empirical matters of fact might differ from those assumed by his creed, amount to nothing less than a rejection of the whole institution of science. Who is "we", and where did "our" conviction and certainty come from? Would Brownback believe these "spiritual truths" if he hadn't been taught them as a child, or brought up in the United States instead of China?

According to Brownback, we should reject scientific findings if they conflict with our faith, but accept them if they're compatible. But the scientific evidence says that humans are big-brained, highly conscious apes that began evolving on the African savannah four million years ago. Are we supposed to reject this as "atheistic theology" (an oxymoron if there ever was one)? The religious conviction that "man" is unique in ways that really matter is compelling in many ways—surely our language, art, music, and science itself are unique products of life on this planet—but holding our uniqueness to be a dogma immune to scientific analysis is an arrogant, and ultimately foolhardy, declaration of authority.

This attitude has enormous political—and educational—implications. What happens if scientific truth conflicts with a politician's "spiritual truth"? This is not a theoretical problem, but a real one, as we see in debates about stem-cell research, abortion, genetic engineering, and global warming. Ignorance about evolution may be widespread, but it's not nearly as dangerous as dogmatic certainty about the real world based on faith alone.

Read it all.

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