So what are we talking about when we talk about God? The geneticist Francis S. Collins bravely sets out to answer this question in light of his scientific knowledge and his Christian faith. Having found for himself "a richly satisfying harmony between the scientific and spiritual worldviews," he seeks to persuade others that "belief in God can be an entirely rational choice, and that the principles of faith are, in fact, complementary with the principles of science."

As a researcher who helped discover the genetic basis for cystic fibrosis and other diseases and as the director of the Human Genome Project, Collins brings strong credentials to the scientific side of his argument. For the spiritual side, he draws on Christian authorities such as Augustine of Hippo, Thomas Aquinas and C.S. Lewis. His aim is to address "extremists on both sides of the science/faith divide." On one extreme are those scientists who insist that the universe is purely and exclusively matter, and on the other are literal interpreters of the Book of Genesis who reject the last two centuries of scientific discovery. Although Collins's purpose is grand, his manner is modest and his prose clear, as befits a man more concerned with sharing his views on the nature of things than with displaying his ego.

Collins writes just enough about his youth for us to learn that he was brought up in a household indifferent to religion; he became an agnostic in college and an atheist in graduate school, where he studied chemistry. Only in medical school did he reverse that trajectory, gradually accepting the existence of God and embracing evangelical Christianity -- led to belief, like St. Augustine, less by longing than by reason.

Reason persuaded him that the universe could not have created itself; that humans possess an intuitive sense of right and wrong, which he calls, following Immanuel Kant, "the Moral Law"; and that humans likewise feel a "longing for the sacred." The source of this longing, the Moral Law and the universe, he came to believe, was the God described in the Bible, a transcendent Creator, Companion, Judge and Redeemer. He found additional evidence of a Creator in the eerie ability of mathematics to map the universe and in the numerous material properties -- from the slight imbalance between matter and anti-matter in the Big Bang to the binding energy within the atomic nucleus -- that seem to have been exquisitely tuned to fashion a world that would give rise to complex forms of life.

The God in whom Collins believes is no aloof Prime Mover who set the show in motion and withdrew to watch. He's a deity who intervenes (albeit rarely) in the course of things. Why God permits the suffering of innocents is a puzzle Collins does not pretend to solve, although he speculates, following C.S. Lewis, that we may need to suffer in order to learn. The resurrection of Jesus is, for Collins, the key intervention by a God "who takes personal interest in human beings." Late in the book, after a lucid account of genetic research and a spirited defense of evolutionary theory against proponents of creationism and "intelligent design," he reveals that on his path toward faith, Jesus was a crucial "bridge between our sinful selves and a holy God."

One can respect his belief in the divinity of Jesus without agreeing that such a belief logically follows from his argument for the existence of God. Likewise, Collins goes beyond the evidence when he speculates that "God's intention in creating the universe" may have been "to lead to creatures with whom He might have fellowship, namely human beings." Many readers will doubt that all 10 or 15 billion years of cosmic history merely prepared the way for us, a pack of inquisitive primates pondering the starry expanses from our speck of planetary dust. Still, it's bracing to be reminded, in our disenchanted day, that an eminent scientist can read the genetic code as sacred speech.

Reviewed by Scott Russell Sanders
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