The scientific insight that our very existence, through evolution, requires a universe of the very size, scale, and age that we see around us implies that the universe, in a certain sense, had us in mind from the very beginning.... If this universe was indeed primed for human life, then it is only fair to say, from a theist's point of view, that each of us is the result of a thought of God, despite the existence of natural processes that gave rise to us.

Miller equates the faith of religious believers with physicists' "faith" in a naturalistic explanation for physical laws:

Believers ... are right to remind skeptics and agnostics that one of their favored explanations for the nature of our existence involves an element of the imagination as wild as any tale in a sacred book: namely, the existence of countless parallel simultaneous universes with which we can never communicate and whose existence we cannot even test. Such belief also requires an extraordinary level of "faith" and the nonreligious would do well to admit as much.

Well, physicists are not ready to admit as much. Contrary to Miller's claim, the existence of multiverses does not require a leap of faith nearly as large as that of imagining a God. And some scientific explanations of the anthropic principle are testable. Indeed, a few predictions of Smolin's theory have already been confirmed, adding to its credibility. It may be wrong, but wait a decade and we will know a lot more about the anthropic principle. In the meantime, it is simply wrong to claim that proposing a provisional and testable scientific hypothesis--not a "belief"--is equivalent to religious faith.

IV.

The most common way to harmonize science and religion is to contend that they are different but complementary ways of understanding the world. That is, there are different "truths" offered by science and by religion that, taken together, answer every question about ourselves and the universe. Giberson explains:

I worry that scientific progress has bewitched us into thinking that there is nothing more to the world than what we can understand.... Science has perhaps gotten as much from the materialistic paradigm as it is going to get. Matter in motion, so elegantly described by Newton and those who followed him, may not be the best way to understand the world.... I think there are ways, though, that we can begin to look at the creation and understand that the scientific view is not all-encompassing. Science provides a partial set of insights that, though powerful, don't answer all the questions.

Usually the questions said to fall outside science include those of meaning, purpose, and morality. In one of his last books, Rocks of Ages: Science and Religion in the Fullness of Life, Stephen Jay Gould called this reconciliation NOMA, for "non-overlapping magisteria": "Science tries to document the factual character of the natural world, and to develop theories that coordinate and explain these facts. Religion, on the other hand, operates in the equally important, but utterly different, realm of human purposes, meanings and values--subjects that the factual domain of science might illuminate, but can never resolve." Gould offered this not as a utopian vision, but as an actual description of why the realms of science and religion do not overlap. As a solution to our perplexity, this is no good. In a spirit of pluralism it ignores the obvious conflicts between them. Gould salvaged his idea by redefining his terms--the old trick, again--writing off creationism as "improper religion" and defining secular sources of ethics, meanings and values as being "fundamentally religious."

The NOMA solution falls apart for other reasons. Despite Gould's claims to the contrary, supernatural phenomena are not completely beyond the realm of science. All scientists can think of certain observations that would convince them of the existence of God or supernatural forces. In a letter to the American biologist Asa Gray, Darwin noted:

Your question what would convince me of Design is a poser. If I saw an angel come down to teach us good, and I was convinced from others seeing him that I was not mad, I should believe in design. If I could be convinced thoroughly that life and mind was in an unknown way a function of other imponderable force, I should be convinced. If man was made of brass or iron and no way connected with any other organism which had ever lived, I should perhaps be convinced. But this is childish writing.

Similarly, if a nine-hundred-foot-tall Jesus appeared to the residents of New York City, as he supposedly did to the evangelist Oral Roberts in Oklahoma, and this apparition were convincingly documented, most scientists would fall on their knees with hosannas.

Scientists do indeed rely on materialistic explanations of nature, but it is important to understand that this is not an a priori philosophical commitment. It is, rather, the best research strategy that has evolved from our long-standing experience with nature. There was a time when God was a part of science. Newton thought that his research on physics helped clarify God's celestial plan. So did Linnaeus, the Swedish botanist who devised our current scheme for organizing species. But over centuries of research we have learned that the idea "God did it" has never advanced our understanding of nature an iota, and that is why we abandoned it. In the early 1800s, the French mathematician Laplace presented Napoleon with a copy of his great five-volume work on the solar system, the Mechanique Celeste. Aware that the books contained no mention of God, Napoleon taunted him, "Monsieur Laplace, they tell me you have written this large book on the system of the universe, and have never even mentioned its Creator." Laplace answered, famously and brusquely: "Je n'avais pas besoin de cette hypothese-la," "I have had no need of that hypothesis." And scientists have not needed it since.

In a common error, Giberson confuses the strategic materialism of science with an absolute commitment to a philosophy of materialism. He claims that "if the face of Jesus appeared on Mount Rushmore with God's name signed underneath, geologists would still have to explain this curious phenomenon as an improbable byproduct of erosion and tectonics." Nonsense. There are so many phenomena that would raise the specter of God or other supernatural forces: faith healers could restore lost vision, the cancers of only good people could go into remission, the dead could return to life, we could find meaningful DNA sequences that could have been placed in our genome only by an intelligent agent, angels could appear in the sky. The fact that no such things have ever been scientifically documented gives us added confidence that we are right to stick with natural explanations for nature. And it explains why so many scientists, who have learned to disregard God as an explanation, have also discarded him as a possibility.

This brings us to the second reason why Gould's explanation does not cohere. It is all well and good to say, as he did, that religion makes no claims about nature, but in practice it is not true. Out of the thousands of religious sects on this planet, only a handful do not have adherents or dogmas that make empirical claims about the world. Here are some. Jesus was born of a virgin and, after crucifixion, came back to life. After Mary's death, her physical body was transported to heaven. The Prophet Mohammed ascended to heaven on the back of a white horse. After death, every being is reincarnated in some other form. The god Brahma emerged from a lotus flower that grew from the navel of Vishnu, and, on Vishnu's command, created the universe. God listens and responds to prayer. Sea mammals come from the chopped-off fingers of the Inuit god Sedna. You will gain wealth and happiness if you send money to the ministry of Creflo Dollar.

Those are the dogmas. To see what the faithful actually believe, consider that more than 60 percent of Americans believe in miracles, the virgin birth of Jesus, his divinity and resurrection (Giberson and Miller are among them), the survival of the soul after death, and the existence of Hell and Satan. Regardless of what liberal theologians claim, most of us are not deists or Unitarians. And if you think that Americans see the Bible as mere metaphorical poetry, I invite you to visit a gospel church in Wasilla, Alaska, or on the South Side of Chicago.

Many religious beliefs can be scientifically tested, at least in principle. Faith-based healing is particularly suited to these tests. Yet time after time it has failed them. After seeing the objects cast off by visitors to Lourdes, Anatole France is said to have remarked, "All those canes, braces and crutches, and not a single glass eye, wooden leg, or toupee!" If God can cure cancer, why is He impotent before missing eyes and limbs? Recent scientific studies of intercessory prayer--when the sick do not know whether they are being prayed for--have not shown the slightest evidence that it works. Nor do we have scientifically rigorous demonstrations of miracles, despite the Vatican's requirement that two miracles be proven for canonizing every saint. Holy relics, such as the Shroud of Turin, have turned out to be clever fakes. There is no corroborated evidence that anyone has spoken from beyond the grave. And what about the ancient "foundational" miracles, such as those supposedly performed by Christ, Buddha, and Mohammed? We were not there when they happened, so we cannot test them. But at least we can apply the same standards to these as we do to other Biblical or Koranic claims.

Like Giberson, Miller rejects a literal interpretation of the Bible. After discussing the fossil record, he contends that "a literal reading of the Genesis story is simply not scientifically valid," concluding that "theology does not and cannot pretend to be scientific, but it can require of itself that it be consistent with science and conversant with it." But this leads to a conundrum. Why reject the story of creation and Noah's Ark because we know that animals evolved, but nevertheless accept the reality of the virgin birth and resurrection of Christ, which are equally at odds with science? After all, biological research suggests the impossibility of human females reproducing asexually, or of anyone reawakening three days after death. Clearly Miller and Giberson, along with many Americans, have some theological views that are not "consistent with science."

What, then, is the nature of "religious truth" that supposedly complements "scientific truth"? The first thing we should ask is whether, and in what sense, religious assertions are "truths." Truth implies the possibility of falsity, so we should have a way of knowing whether religious truths are wrong. But unlike scientific truths, religious ones differ from person to person and sect to sect. And we all know of clear contradictions between the "truths" of different faiths. Christianity unambiguously claims the divinity of Jesus, and many assert that the road to salvation absolutely depends on accepting this claim, whereas the Koran states flatly that anyone accepting the divinity of Jesus will spend eternity in hell. These claims cannot both be "true," at least in a way that does not require intellectual contortions.

Assertions about God's nature also differ among faiths. Giberson explains, for example, that "centuries of Christian reflection on the nature of God have highlighted various characteristics of God: justice, love, goodness, holiness, grace, sovereignty, and so forth." But to those of other faiths, God can be vengeful, as Yahweh was in the Old Testament. Jews cannot imagine an incarnated God, the Word made flesh. Hindus, like ancient Greeks, accept multiple gods with different personalities. To deists, god is apathetic, while many theologians in all the monotheistic faiths claim that we cannot know anything about God's attributes. So which of these many characterizations is "true"? Anything touted as a "truth" must come with a method for being disproved--a method that does not depend on personal revelation. After all, thousands of people have had delusional revelations of "truth" with horrifying consequences.

Perhaps what we mean by "religious truths" are "moral truths," such as "Thou shalt not commit adultery." These rules are not subject to empirical testing, but they do comport with our reasoned sense of right and wrong. But for almost every "truth" such as this there is another one believed with equal sincerity, such as "Those who commit adultery should be stoned to death." This dictum appears not only in Islamic religious law, but in the Old Testament as well. (It seems wrong, by the way, to call these truths religious. Beginning with Plato, philosophers have argued convincingly that our ethics come not from religion, but from a secular morality that develops in intelligent, socially interacting creatures, and is simply inserted into religion for convenient citation.)

In the end, then, there is a fundamental distinction between scientific truths and religious truths, however you construe them. The difference rests on how you answer one question: how would I know if I were wrong? Darwin's colleague Thomas Huxley remarked that "science is organized common sense where many a beautiful theory was killed by an ugly fact." As with any scientific theory, there are potentially many ugly facts that could kill Darwinism. Two of these would be the presence of human fossils and dinosaur fossils side by side, and the existence of adaptations in one species that benefit only a different species. Since no such facts have ever appeared, we continue to accept evolution as true. Religious beliefs, on the other hand, are immune to ugly facts. Indeed, they are maintained in the face of ugly facts, such as the impotence of prayer. There is no way to adjudicate between conflicting religious truths as we can between competing scientific explanations. Most scientists can tell you what observations would convince them of God's existence, but I have never met a religious person who could tell me what would disprove it. And what could possibly convince people to abandon their belief that the deity is, as Giberson asserts, good, loving, and just? If the Holocaust cannot do it, then nothing will.

V.

Giberson and Miller are thoughtful men of good will. Reading them, you get a sense of conviction and sincerity absent from the writings of many creationists, who blatantly deny the most obvious facts about nature in the cause of their faith. Both of their books are worth reading: Giberson for the history of the creation/ evolution debate, and Miller for his lucid arguments against intelligent design. Yet in the end they fail to achieve their longed-for union between faith and evolution. And they fail for the same reason that people always fail: a true harmony between science and religion requires either doing away with most people's religion and replacing it with a watered-down deism, or polluting science with unnecessary, untestable, and unreasonable spiritual claims.

Although Giberson and Miller see themselves as opponents of creationism, in devising a compatibility between science and religion they finally converge with their opponents. In fact, they exhibit at least three of the four distinguishing traits of creationists: belief in God, the intervention of God in nature, and a special role for God in the evolution of humans. They may even show the fourth trait, a belief in irreducible complexity, by proposing that a soul could not have evolved, but was inserted by God.

Giberson, while abjuring a hands-on God, nevertheless sees deliberate design in our Earth.

Why is [bird] song so pleasant to hear? Why, for example, does almost every scene of undeveloped nature seem so beautiful, from mountain lakes to rolling prairies? If the evolution of our species was driven entirely by survival considerations, then where did we get our rich sense of natural aesthetics?... There is an artistic character to nature that has always struck me as redundant from a purely scientific point of view.... I am attracted to the idea that God's signature is not on the engineering marvels of the natural world, but rather on its marvelous creativity and aesthetic depth. Scientists are not supposed to talk about God this way, for it raises questions that can't be answered.

This is aesthetic design rather than intelligent design, but it is still design. And it ignores scientific explanations, such as E.O. Wilson's "biophilia" theory, which suggests that we evolved to find places like lakes and prairies attractive simply because they provided our ancestors with food and safety.

And neither Miller nor Giberson tell us what circumstances would make them abandon their belief in a personal God. Giberson, in fact, asserts that he cannot be wrong:

As a believer in God, I am convinced in advance that the world is not an accident and that, in some mysterious way, our existence is an "expected" result. No data would dispel it. Thus, I do not look at natural history as a source of data to determine whether or not the world has purpose. Rather, my approach is to anticipate that the facts of natural history will be compatible with the purpose and meaning I have encountered elsewhere. And my understanding of science does nothing to dissuade me from this conviction.

This is creationist-speak, pure and simple. No real scientist would say that his theories are immune to disproof. And so Giberson's personal reconciliation, however edifying it is to him spiritually, must be intellectually unconvincing to the rest of us.

Besides his "aesthetic design" argument, Giberson offers another reason for his faith--we might call it the argument from convenience.

As a purely practical matter, I have compelling reasons to believe in God. My parents are deeply committed Christians and would be devastated, were I to reject my faith. My wife and children believe in God, and we attend church together regularly. Most of my friends are believers. I have a job I love at a Christian college that would be forced to dismiss me if I were to reject the faith that underpins the mission of the college. Abandoning belief in God would be disruptive, sending my life completely off the rails.

This touching confession reveals the sad irrationality of the whole enterprise--the demoralizing conflict between a personal need to believe and a desperation to show that this primal need is perfectly compatible with science.

It would appear, then, that one cannot be coherently religious and scientific at the same time. That alleged synthesis requires that with one part of your brain you accept only those things that are tested and supported by agreed-upon evidence, logic, and reason, while with the other part of your brain you accept things that are unsupportable or even falsified. In other words, the price of philosophical harmony is cognitive dissonance. Accepting both science and conventional faith leaves you with a double standard: rational on the origin of blood clotting, irrational on the Resurrection; rational on dinosaurs, irrational on virgin births. Without good cause, Giberson and Miller pick and choose what they believe. At least the young-earth creationists are consistent, for they embrace supernatural causation across the board. With his usual flair, the physicist Richard Feynman characterized this difference: "Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool." With religion, there is just no way to know if you are fooling yourself.

So the most important conflict--the one ignored by Giberson and Miller--is not between religion and science. It is between religion and secular reason. Secular reason includes science, but also embraces moral and political philosophy, mathematics, logic, history, journalism, and social science--every area that requires us to have good reasons for what we believe. Now I am not claiming that all faith is incompatible with science and secular reason--only those faiths whose claims about the nature of the universe flatly contradict scientific observations. Pantheism and some forms of Buddhism seem to pass the test. But the vast majority of the faithful--those 90 percent of Americans who believe in a personal God, most Muslims, Jews, and Hindus, and adherents to hundreds of other faiths--fall into the "incompatible" category.

Unfortunately, some theologians with a deistic bent seem to think that they speak for all the faithful. These were the critics who denounced Dawkins and his colleagues for not grappling with every subtle theological argument for the existence of God, for not steeping themselves in the complex history of theology. Dawkins in particular was attacked for writing The God Delusion as a "middlebrow" book. But that misses the point. He did indeed produce a middlebrow book, but precisely because he was discussing religion as it is lived and practiced by real people. The reason that many liberal theologians see religion and evolution as harmonious is that they espouse a theology not only alien but unrecognizable as religion to most Americans.

Statistics support this incompatibility. For example, among those thirty-four countries surveyed, we see a statistically strong negative relationship between the degree of faith and the acceptance of evolution. Countries such as Denmark, France, Japan and the United Kingdom have a high acceptance of Darwinism and low belief in God, while the situation is reversed in countries like Bulgaria, Latvia, Turkey, and the United States. And within America, scientists as a group are considerably less religious than non-scientists. This is not say that such statistics can determine the outcome of a philosophical debate. Nor does it matter whether these statistics mean that accepting science erodes religious faith, or that having faith erodes acceptance of science. (Both processes must surely occur.) What they do show, though, is that people have trouble accepting both at the same time. And given the substance of these respective worldviews, this is no surprise.

This disharmony is a dirty little secret in scientific circles. It is in our personal and professional interest to proclaim that science and religion are perfectly harmonious. After all, we want our grants funded by the government, and our schoolchildren exposed to real science instead of creationism. Liberal religious people have been important allies in our struggle against creationism, and it is not pleasant to alienate them by declaring how we feel. This is why, as a tactical matter, groups such as the National Academy of Sciences claim that religion and science do not conflict. But their main evidence--the existence of religious scientists--is wearing thin as scientists grow ever more vociferous about their lack of faith. Now Darwin Year is upon us, and we can expect more books like those by Kenneth Miller and Karl Giberson. Attempts to reconcile God and evolution keep rolling off the intellectual assembly line. It never stops, because the reconciliation never works.

Jerry A. Coyne is a professor in the Department of Ecology and Evolution at the University of Chicago. His new book, Why Evolution Is True, has just been published by Viking.