The holiday buying season may seem like the triumph of mindless materialism over all other values. But it is framed by two highly significant religious festivals, one ancient and one modern.
Christmas is the result of Roman emperors’ search for a creed that would unite the many different cultures under their sway. By the third century A.D., it was evident that the staid gods of the Roman pantheon could not compete with compelling new cults of Dionysus, Attis, or Cybele. The emperor Aurelian decided to revamp the pantheon by making Sol, the sun God, its principal divinity, and by declaring the winter solstice a national holiday for Sol’s birthday. But Constantine, who came to power some 30 years later, favored Christianity as the imperial creed, a choice that his eventual successor Theodosius made official in 380 A.D. The birthday celebrated on Dec. 25 became that of Jesus, not Sol.
Thanksgiving is the chief annual festival of a religion that few have heard of but every American belongs to. It’s known to sociologists as American Civil Religion. Its chief officer is the president, whose sacerdotal art consists of sticking to generic invocations of the deity. Its sacred texts include President Kennedy’s inaugural address and Martin Luther King’s “I have a dream” speech. Americans are so devoted to its credo that we carry many copies in our purse or pocket—the motto “In God we trust” that is stamped on every coin.
Despite the vast differences in time and space, Christmas in the Roman Empire and Thanksgiving in the United States were intended to play the same role—that of uniting people of many creeds and sects in a common faith. Indeed, this is the function of religion in every society: to get everyone emotionally committed to a common goal and ready to put their community’s interest ahead of their selfish interests, even up to the sacrifice of their life.
Many people think of religion in personal terms, of the solace or insight or exaltation it can provide. Religion is indeed personally satisfying and can elicit some of the deepest emotions of which the mind is capable. But it’s through its social effects that religion has played such a crucial role in history. It’s the Krazy Glue of human sociality, capable of establishing cohesion within human groups of any size, from a hunter-gatherer band of 50 people, to an empire of millions, to civilizations that include many different countries, such as that of Western Christianity or Islam.
Given that religious behavior is found in every society in the world, it’s reasonable to consider it from an evolutionary perspective and ask whether it arose in early human groups because it was favored by natural selection. This, I believe, is a fruitful line of inquiry and one that explains many otherwise puzzling features of religion, in particular why the basic form of religion is so similar from one society to another, even though its cultural form varies widely.
One common feature of religions is that of supernatural agents. The gods live in a supernatural world and yet they are not unreachable. Their behavior can be manipulated through prayer and sacrifice. The gods, for their part, issue laws that people obey for fear of divine punishment. Some may seem arbitrary (wear a yarmulke, eat fish on Fridays, don’t eat pork) but in practice serve the useful role of distinguishing adherents from nonbelievers. More important, the laws contain rules that deeply affect the social fabric. Many urge restraint toward other members of the community (“Do as you would be done by”) and others regulate reproductive behavior, usually in the direction of increasing fertility.
So think back to the early days of modern human existence before we dispersed from our homeland in northeast Africa some 50,000 years ago. We lived in small, mobile groups as hunters and gatherers. To judge by living hunter-gatherer peoples, these groups would have been fiercely egalitarian, with no head men or chiefs. How does one make 100 selfish individuals subordinate their own interest to that of the community? How does one enforce compliance when one does not possess law books, police force, courts, or prison?
Religion was the deft solution to this pressing social dilemma. Through all-night dance sessions, using rhythmic movement in unison to foster emotional bonds of community, primitive peoples generated the group cohesion necessary for their survival. People obeyed community laws for fear of divine punishment. Since the overseer was in people’s heads, no police force was necessary. The community implicitly negotiated with the gods the rules that seemed likely to ensure the group’s survival. Rules about the distribution of women—marriage rites—ensured social peace. Rules to enhance the moral fabric raised the quality of life and made the community worth defending. Rules to enhance fertility enlarged the population and gave strength in numbers. The prospect of divine favor made warriors willing to lay down their lives for their community, a remarkable overruling of the individual will to survive.
It’s easy to envisage that societies that practiced religion would in time have prevailed over those that were less cohesive. The tendency to learn and emotionally commit oneself to the religion of one’s community, I argue in The Faith Instinct, became engraved by natural selection on our neural circuits. Because this behavior had become universal before the dispersal of the modern human population from Africa, all known societies practice religion in one form or another.
When the first settled societies appeared, starting some 15,000 years ago, social hierarchies replaced the egalitarianism of hunter gatherer communities. Priests interposed themselves between the community and its gods. Leaders invoked the authority of religion, often appointing themselves chief priest. Religion helped make people apply themselves to the unaccustomed hard labor of working the fields in the first societies to practice agriculture; hence the ancient association of religion with agricultural festivals of the spring and autumn. Passover grew from a Canaanite festival marking the barley harvest, before being reassigned in Judaism to the deliverance of the Israelites from Egypt.
In primitive societies, religion governed almost every aspect of daily life. In many modern states, religion has been pushed into the background as state institutions take over many of its ancient roles. But it still shapes the nature and fabric of human societies. Even those who say they pay no attention to religion move to the social rhythms set by Thanksgiving and Christmas.
Nicholas Wade has worked for The New York Times as an editorial writer, editor and science reporter. Before writing for the Times, he worked at two leading scientific journals, as deputy editor of Nature magazine in London, and on the news staff of Science magazine in Washington. He is the author of six previous books.