I might mean that religion is not an artifact, not a product of human intellectual activity. Sneezing and belching are natural, reciting sonnets is not; going naked—au naturel—is natural; wearing clothes is not. But it is obviously false that religion is natural in this sense. Religions are transmitted culturally, through language and symbolism, not through the genes. You may get your father’s nose and your mother’s musical ability through your genes, but if you get your religion from your parents, you get it the way you get your language, through upbringing. So of course that is not what I mean by natural.
With a slightly different emphasis, I might mean that religion is doing what comes naturally, not an acquired taste, or an artificially groomed or educated taste. In this sense, speaking is natural but writing is not; drinking milk is natural but drinking a dry martini is not; listening to tonal music is natural but listening to atonal music is not; gazing at sunsets is natural but gazing at late Picasso paintings is not. There is some truth to this: religion is not an unnatural act, and this will be a topic explored in this book. But it is not what I mean.
I might mean that religion is natural as opposed to supernatural, that it is a human phenomenon composed of events, organisms, objects, structures, patterns, and the like that all obey the laws of physics or biology, and hence do not involve miracles. And that is what I mean. Notice that it could be true that God exists, that God is indeed the intelligent, conscious, loving creator of us all, and yet still religion itself, as a complex set of phenomena, is a perfectly natural phenomenon. Nobody would think it was presupposing atheism to write a book subtitled Sports as a Natural Phenomenon or Cancer as a Natural Phenomenon. Both sports and cancer are widely recognized as natural phenomena, not supernatural, in spite of the well-known exaggerations of various promoters. (I’m thinking, for instance, of two famous touchdown passes known respectively as the Hail Mary and the Immaculate Reception, to say nothing of the weekly trumpetings by researchers and clinics around the world of one “miraculous†cancer cure or another.)
Sports and cancer are the subject of intense scientific scrutiny by researchers working in many disciplines and holding many different religious views. They all assume, tentatively and for the sake of science, that the phenomena they are studying are natural phenomena. This doesn’t prejudge the verdict that they are. Perhaps there are sports miracles that actually defy the laws of nature; perhaps some cancer cures are miracles. If so, the only hope of ever demonstrating this to a doubting world would be by adopting the scientific method, with its assumption of no miracles, and showing that science was utterly unable to account for the phenomena. Miracle-hunters must be scrupulous scientists or else they are wasting their time—a point long recognized by the Roman Catholic Church, which at least goes through the motions of subjecting the claims of miracles made on behalf of candidates for sainthood to objective scientific investigation. So no deeply religious person should object to the scientific study of religion with the presumption that it is an entirely natural phenomenon. If it isn’t entirely natural, if there really are miracles involved, the best way—indeed, the only way—to show that to doubters would be to demonstrate it scientifically. Refusing to play by these rules only creates the suspicion that one doesn’t really believe that religion is supernatural after all.
In assuming that religion is a natural phenomenon, I am not prejudging its value to human life, one way or the other. Religion, like love and music, is natural. But so are smoking, war, and death. In this sense of natural, everything artificial is natural! The Aswan Dam is no less natural than a beaver’s dam, and the beauty of a skyscraper is no less natural than the beauty of a sunset. The natural sciences take everything in Nature as their topic, and that includes both jungles and cities, both birds and airplanes, the good, the bad, the ugly, the insignificant, and the all-important as well.