Virtually all religions hold some supernatural beliefs specific to that religion. That is, a religion’s adherents firmly hold beliefs that conflict with and cannot be confirmed by our experience of the natural world, and that appear implausible to people other than the adherents of that particular religion. For example, Hindus believe there is a monkey god who travels thousands of kilometers at a single somersault. Catholics believe a woman who had not yet been fertilized by a man became pregnant and gave birth to a baby boy, whose body eventually after his death was carried up to a place called heaven, often represented as being located in the sky. The Jewish faith believes that a supernatural being gave a chunk of desert in the Middle East to the being's favorite people, as their home forever.
No other feature of religion creates a bigger divide between religious believers and modern secular people, to whom it staggers the imagination that anyone could entertain such beliefs. No other feature creates a bigger divide between believers in two different religions, each of whom firmly believes its own beliefs but considers it absurd that the other religion’s believers believe those other beliefs. Why, nevertheless, are supernatural beliefs such universal features of religions?
One suggested answer is that supernatural religious beliefs are just ignorant superstitions similar to supernatural non-religious beliefs, illustrating only that the human brain is capable of deceiving itself into believing anything. We can all think of supernatural non-religious beliefs whose implausibility should be obvious. Many Europeans believe that the sight of a black cat heralds misfortune, but black cats are actually rather common. By repeatedly tallying whether or not a one-hour period following or not following your observation of a black cat in an area with high cat density did or did not bring you some specified level of misfortune, and by applying the statistician’s chi-square test, you can quickly convince yourself that the black-cat hypothesis has a probability of less than 1 out of 1,000 of being true. Some groups of New Guinea lowlanders believe that hearing the beautiful whistled song of the little bird known as the Lowland Mouse-Babbler warns us that someone has recently died, but this bird is among the most common species and most frequent singers in New Guinea lowland forests. If the belief about it were true, the local human population would be dead within a few days, yet my New Guinea friends are as convinced of the babbler’s ill omens as Europeans are afraid of black cats.
A more striking non-religious superstition, because people today still invest money in their mistaken belief, is water-witching, also variously known as dowsing, divining, or rhabdomancy. Already established in Europe over 400 years ago and possibly also reported before the time of Christ, this belief maintains that rotation of a forked twig carried by a practitioner called a dowser, walking over terrain whose owner wants to know where to dig a well, indicates the location and sometimes the depth of an invisible underground water supply. Control tests show that dowsers’ success at locating underground water is no better than random, but many land-owners in areas where geologists also have difficulty at predicting the location of underground water nevertheless pay dowsers for their search, then spend even more money to dig a well unlikely to yield water. The psychology behind such beliefs is that we remember the hits and forget the misses, so that whatever superstitious beliefs we hold become confirmed by even the flimsiest of evidence through the remembered hits. Such anecdotal thinking comes naturally; controlled experiments and scientific methods to distinguish between random and non-random phenomena are counterintuitive and unnatural, and thus not found in traditional societies.
Perhaps, then, religious superstitions are just further evidence of human fallibility, like belief in black cats and other non-religious superstitions. But it’s suspicious that costly commitments to belief in implausible-to-others religious superstitions are such a consistent feature of religions. The investments that many religious adherents make to their beliefs are far more burdensome, time-consuming, and heavy in consequences to them than are the actions of black-cat-phobics in occasionally avoiding black cats. This suggests that religious superstitions aren’t just an accidental by-product of human reasoning powers but possess some deeper meaning. What might that be?
A recent interpretation among some scholars of religion is that belief in religious superstitions serves to display one’s commitment to one’s religion. All long-lasting human groups — Boston Red Sox fans (like me), devoted Catholics, patriotic Japanese, and others — face the same basic problem of identifying who can be trusted to remain as a group member. The more of one’s life is wrapped up with one’s group, the more crucial it is to be able to identify group members correctly and not to be deceived by someone who seeks temporary advantage by claiming to share your ideals but who really doesn’t. If that man carrying a Boston Red Sox banner, whom you had accepted as a fellow Red Sox fan, suddenly cheers when the New York Yankees hit a home run, you’ll find it humiliating but not life-threatening. But if he’s a soldier next to you in the front line and he drops his gun (or turns it on you) when the enemy attacks, your misreading of him may cost you your life.
That’s why religious affiliation involves so many overt displays to demonstrate the sincerity of your commitment: sacrifices of time and resources, enduring of hardships, and other costly displays that I’ll discuss later. One such display might be to espouse some irrational belief that contradicts the evidence of our senses, and that people outside our religion would never believe. If you claim that the founder of your church had been conceived by normal sexual intercourse between his mother and father, anyone else would believe that too, and you’ve done nothing to demonstrate your commitment to your church. But if you insist, despite all evidence to the contrary, that he was born of a virgin birth, and nobody has been able to shake you of that irrational belief after many decades of your life, then your fellow believers will feel much more confident that you’ll persist in your belief and can be trusted not to abandon your group.
Nevertheless, it’s not the case that there are no limits to what can be accepted as a religious supernatural belief. Scott Atran and Pascal Boyer have independently pointed out that actual religious superstitions over the whole world constitute a narrow subset of all the arbitrary random superstitions that one could theoretically invent. To quote Pascal Boyer, there is no religion proclaiming anything like the following tenet: “There is only one God! He is omnipotent. But he exists only on Wednesdays.” Instead, the religious supernatural beings in which we believe are surprisingly similar to humans, animals, or other natural objects, except for having superior powers. They are more far-sighted, longer-lived, and stronger, travel faster, can predict the future, can change shape, can pass through walls, and so on. In other respects, gods and ghosts behave like people. The god of the Old Testament got angry, while Greek gods and goddesses became jealous, ate, drank, and had sex. Their powers surpassing human powers are projections of our own personal power fantasies; they can do what we wish we could do ourselves. I do have fantasies of hurling thunderbolts that destroy evil people, and probably many other people share those fantasies of mine, but I have never fantasized about existing only on Wednesdays. Hence it doesn’t surprise me that gods in many religions are pictured as smiting evil-doers, but that no religion holds out the dream of existing just on Wednesdays. Thus, religious supernatural beliefs are irrational, but emotionally plausible and satisfying. That’s why they’re so believable, despite at the same time being rationally implausible.
Printed by arrangement with Viking Penguin, a member of Penguin Group (USA) Inc. from "The World Until Yesterday: What Can We Learn from Traditional Societies?" by Jared Diamond. Copyright © Jared Diamond, 2012.