(2 of 9)
Even among people who regard spiritual life as wishful hocus-pocus, there is a growing sense that humans may not be able to survive without it. It's hard enough getting by in a fang-and-claw world in which killing, thieving and cheating pay such rich dividends. It's harder still when there's no moral cop walking the beat to blow the whistle when things get out of control. Best to have a deity on hand to rein in our worst impulses, bring out our best and, not incidentally, give us a sense that there's someone awake in the cosmic house when the lights go out at night and we find ourselves wondering just why we're here in the first place. If a God or even several gods can do all that, fine. And if we sometimes misuse the idea of our gods--and millenniums of holy wars prove that we do--the benefits of being a spiritual species will surely outweigh the bloodshed.
Far from being an evolutionary luxury then, the need for God may be a crucial trait stamped deeper and deeper into our genome with every passing generation. Humans who developed a spiritual sense thrived and bequeathed that trait to their offspring. Those who didn't risked dying out in chaos and killing. The evolutionary equation is a simple but powerful one.
Nowhere has that idea received a more intriguing going-over than in the recently published book The God Gene: How Faith Is Hardwired into Our Genes (Doubleday; 256 pages), by molecular biologist Dean Hamer. Chief of gene structure at the National Cancer Institute, Hamer not only claims that human spirituality is an adaptive trait, but he also says he has located one of the genes responsible, a gene that just happens to also code for production of the neurotransmitters that regulate our moods. Our most profound feelings of spirituality, according to a literal reading of Hamer's work, may be due to little more than an occasional shot of intoxicating brain chemicals governed by our DNA. "I'm a believer that every thought we think and every feeling we feel is the result of activity in the brain," Hamer says. "I think we follow the basic law of nature, which is that we're a bunch of chemical reactions running around in a bag."
Even for the casually religious, such seeming reductionism can rankle. The very meaning of faith, after all, is to hold fast to something without all the tidy cause and effect that science finds so necessary. Try parsing things the way geneticists do, and you risk parsing them into dust. "God is not something that can be demonstrated logically or rigorously," says Neil Gillman, a professor of Jewish philosophy at the Jewish Theological Seminary in New York City. "[The idea of a God gene] goes against all my personal theological convictions." John Polkinghorne, a physicist who is also Canon Theologian at England's Liverpool Cathedral, agrees: "You can't cut [faith] down to the lowest common denominator of genetic survival. It shows the poverty of reductionist thinking."