As a biological anthropologist, I suggest that our religious impulses evolved from a fundamental, evolutionarily old need for belongingness— for mattering to and connecting with others in a deeply emotional way. We humans have evolved to crave belongingness, and we seek it with other people, and with God, gods, and spirits.

Our ancestors first became tool-makers, and later, clever hunters. When textbook images and museum dioramas focus only on spear-wielding and fire-making, though, they miss the most fascinating aspects of our past. Judging from what we know of other primates, our ancestors felt deep affection for family and friends, and mourned their deaths. Empathy and compassion, just as much as aggression and violence, made up the prehistoric behavioral repertoire.

No scientist can fail to grasp the importance of genetics in evolutionary processes. But theories that posit religion as a byproduct of ancient brains tell us little about meaning-making in our flesh-and-blood human ancestors, and theories of God genes tell us even less. What’s key to explore are the ways people related with each other as they began to confront life’s (and death’s) timeless mysteries.

If we look at the archeology of the Neanderthals, those enigmatic close cousins of ours, we see tantalizing hints of emerging spirituality in communal burial rituals. After about 70,000 years ago, our own species (Homo Sapiens) began to create more elaborate symbol-laced ceremonies and to paint on cave walls and ceilings in ways that cry out for spiritual interpretations.

Alternative hypotheses for apparent spiritual practices must always be pursued in order for good science to take place, and there’s no need to think that every burial or ritual would have had spiritual overtones. Yet looking at the evidence from our past, it seems indisputable that we evolved as spiritual beings. This perspective frees us to bring together science and religion in a way that honors both.

I don’t tell the Evolving God story to imply that somehow it is more progressive--or more moral or more right—to be religious today. A truly evolved perspective leads us to respect as equals all those who practice love and compassionate action in the world, whether that action is faith-based or rooted in agnosis or atheism.

Walk into a bookstore these days, and it’s hard to miss evidence of a relentless wave of books by scientists who write about religion. Some are divisive and shrill, others embracing and enlightening. Most, right now, are deeply personal. It’s a hot trend for scientists to proclaim either a deep faith in God or a hostile rejection of God. I’m here to affirm that there’s a role too for the scientist who says nothing personal about God.

Barbara J. King is Class of 2007 Professor of Anthropology at the College of William and Mary. Her new book is Evolving God: A Provocative View of the Origins of Religion (Doubleday, 2007).