Can science, religion coexist in peace?

Almost 14 billion years after the big bang, and 3.5 billion years since the first bacteria appeared on Earth, humans occupy just one branch of the tree of life.

We share an evolutionary limb with other eukaryotes, creatures whose membrane-bound cells carry genetic material. Our biological neighbors developed over time just as we did, by the evolutionary forces of mutation and natural selection. They include plants, fungi, and slime molds.

Despite that humble company, said Martin A. Nowak, Harvard professor of mathematics and biology, humans have a profound “claim to fame” — language. He called the acquisition of complex expression “the only truly interesting thing to happen in the last 600 million years,” and the most important of all evolutionary events.

Language is as little as 100,000 years old, said Nowak in a March 8 lecture at Harvard Divinity School. But it is the evolutionary gift that accelerated cultural development, allowing us to become “hopeful, generous, and forgiving,” he said. “We are as different from animals as any theologian wants [us] to be.”

“Evolution and Christianity” was the ninth in a series of lectures sponsored by the Evolution and Theology of Cooperation Project at Harvard University. The three-year project, supported by the John Templeton Foundation, is directed by Nowak and Sarah Coakley, Edward Mallinckrodt Jr. Professor of Divinity.

In most of the 4 billion years of life on Earth, gene sequences were the only way information was encoded for evolutionary purposes, said Nowak, who is the director of Harvard’s Program for Evolutionary Dynamics. Then along came human language, an ever-growing repertoire of signals that evolved from adapting ancient regions of the primate brain once only used to decipher sounds and control facial muscles.

Language propelled evolution out of a purely genetic realm, where it still operates, into the realm of culture, Nowak said. “There’s a structural evolution of the brain going on, in a very, very fast timescale.”

Language accelerates cooperation, an evolutionary feature that — starting with the first multicellular creatures — is present in robust organisms. “You move to higher levels in evolution whenever you manage to get cooperation,” Nowak said.

Cooperation made even social organisms more robust, said Nowak, and allowed humans to rapidly evolve into “the world champions of cooperation.”

In cultural terms, cooperation evolved first as kin selection, by which close relations have the highest social importance. Nowak quoted the late British evolutionary biologist J.B.S. Haldane: “I will jump into the river to save two brothers — or eight cousins.”

Cooperation spread out to include groups, clusters of groups, and finally to humanity at large. “Indirect reciprocity,” for instance, is the closest that evolutionary cooperation comes to what might be called altruism. It means helping others simply because you’ve observed others being helped. “That’s really what people are always about,” said Nowak.

In mathematical terms, he said, kinship selection and other mechanisms of the evolution of cooperation show a favorable cost-benefit analysis. In social terms, “the winning strategies have nice attributes,” said Nowak. That’s where being “hopeful, generous, and forgiving” comes in, he said, along with the evolution of religious feeling.

The evolution of cooperation lays out common ground for the scientist and the theologian.

“Religion, like language, is a human universal,” said Nowak, and should not threaten scientists. In turn, he said, evolution should be “as little problem for religion as [the concept of] gravity.”

But in the public arena, evolution is still an issue that keeps scientists and theologians apart, and creates undeniable tensions.

Religious opposition has coalesced into three camps. Creationists hold that the Book of Genesis is a scientific account of historical events on an Earth just 6,000 years old, and therefore evolution is impossible. That’s “bad science,” said Nowak. And perhaps bad theology, too, since it runs counter to the idea, adapted by Thomas Aquinas and other theologians, that God is best explained in terms of analogy.

Proponents of “intelligent design” hold that evolution is largely correct, but that some living structures are so complex they require the hand of God to create. “Weak science,” said Nowak — and weak theology, since it posits a God “who is sometimes here and sometimes away.”

Scientific atheism holds that science provides everything needed to understand the world. It’s the strongest challenge to religion, said Nowak. “But to say science disproves God,” he said, “goes beyond what science really says.”

Science and religion provide analogous functions, said Nowak. They allay human suffering by offering guidance through a mysterious world, while simply occupying “different ecological niches in the brain,” he said. “Science and religion are two essential components in the search for truth. Denying either is a barren approach.”

By itself, intellectual (scientific) life is “inherently unstable,” and is unable to answer the kind of questions religion can — like the meaning of life, said Nowak. “There are no equivalent questions in science.”

To illustrate the instability of relying on science alone, he used the analogy of Mr. Spock on “Star Trek.” He was “only a scientist — hyperrational,” said Nowak. “And that’s always funny.”

Science and religion fulfill separate roles, like two languages always searching for the right word. “Even as a scientist, I am free to assume the best possible world,” said Nowak, who is content with the parallel lexicons of the two realms. “That makes perfect sense.”