Religion has been waning in influence for several centuries, especially in Europe and North America. There have been a few brief and local revivals, but in recent years the pace of decline has accelerated.  Today one of the largest categories of religious affiliation in the world—with more than a billion people—is no religion at all, the “Nones.” One out of six Americans is already a None; by 2050, the figure will be one out of four, according to a new Pew Research Center study. Churches are being closed by the hundreds, deconsecrated and rehabilitated as housing, offices, restaurants and the like, or just abandoned.  If this trend continues, religion largely will evaporate, at least in the West. Pockets of intense religious activity may continue, made up of people who will be more sharply differentiated from most of society in attitudes and customs, a likely source of growing tension and conflict.  Could anything turn this decline around? Yes, unfortunately. A global plague, a world war fought over water or oil, the collapse of the Internet (and thereby almost all electronic communication) or some as-yet unimagined catastrophe could throw the remaining population into misery and fear, the soil in which religion flourishes best.  With hardly any significant exceptions, religion recedes whenever human security and well-being rises, a fact that has recently been shown in numerous studies, but was suspected by John Calvin in the 16th century. He noted that the more prosperous and comfortable his Genevans became, the less dependent they were on church. Presumably, those who deplore the decline of religion in the world today would not welcome the sort of devastation and despair that could give religion its second wind.  There is no other plausible scenario that could halt the slide, for a fairly obvious reason: the recent rapid growth of mutual knowledge, thanks to the global spread of electronic and digital communication.  Any institution—just like a person or an organism—depends on a modicum of privacy in which to conduct its business and control its activities without too much interference and too many prying eyes. Religious institutions, since their founding millennia ago, have managed to keep secrets and to control what their flocks knew about the world, about other religions and about the inner workings of their own religion with relative ease. Today it is next to impossible.  What is particularly corrosive to religion isn’t just the newly available information that can be unearthed by the curious, but the ambient knowledge that is shared by the general populace.  Laughter is particularly subversive. A Mormon watching the episode of “South Park” that lampoons the Church of Jesus Christ of Latter-day Saints doesn’t just see some outsiders poking fun at her religion. She learns that vast numbers of people find her religion comical, preposterous, ludicrous, as confirmed by the writers’ decision to belittle it and the networks’ decision to broadcast it. This may heighten her loyalty, but it also may shake her confidence, and as soon as she even entertains the hypothesis that belief in God might be a life-enhancing illusion, not a rock-solid truth, she is on the slippery slope.  The late computer scientist John McCarthy, a founder of artificial intelligence, once said, “When I see a slippery slope, my instinct is to build a terrace.” That’s what theologians have been doing for hundreds of years, shoring up whatever they think they can salvage from the rain of information eroding their ancient peaks of doctrine. In some denominations the clergy are obliged to swear to uphold the “inerrant truth” of every sentence in the Bible, but this is becoming more of an embarrassment than a shield against doubt.  Hardly anybody today believes in—or would want to believe in—the wrathful, Old Testament Jehovah, for instance. A God who commands our love is a nasty piece of work by today’s perspectives, and has been replaced, over the centuries, by ever-less-anthropomorphic (but more “loving,” more “forgiving”) addressees of our prayers. (Isn’t it curious how the obsolete term “God-fearing” is still used in some quarters as a commendation?) God has no ears, but may “listen” to our prayers, and “works in mysterious ways,” which is a face-saving way of acknowledging that He doesn’t answer them at all.  Do you remember the impressive and rigorous Benson Study? It was conducted by a Harvard Medical School team that labored for years. It was finally published in 2006, and it concluded that intercessionary prayer for the recovery of heart-surgery patients not only didn’t work; in some conditions it showed a small but measurable increase in post-surgical complications.  This was dutifully reported by the media, and promptly forgotten by most. But if the study had found any positive result, you can be sure it would have been on the cover of all the newsmagazines and featured in television specials. This pro-religion bias in the media is crumbling, however, and once it dissolves, the exposure of all the antique falsehoods of religious doctrine will oblige the theologians to build yet another terrace, lower down the slope. They are running out of rocks.  Religious leaders of all faiths are struggling to find ways of keeping their institutions going, and one of the themes emerging from the surveys they conduct is that creed should be de-emphasized and loyalty and community should be fostered.  If we are lucky—if human health and security continue to rise and spread around the globe—churches might evolve into humanist communities and social clubs, dedicated to good works, with distinctive ceremonies and disappearing doctrine, except for a scattering of reclusive sects marked by something like institutional paranoia.  If we are unlucky and calamity strikes, our anxiety and misery will provide plenty of fuel for revivals and inventions of religions we have happily learned to live without.  Prof. Dennett is co-director of the Center for Cognitive Studies at Tufts University and co-author, with Linda LaScola, of “Caught in the Pulpit: Leaving Belief Behind.” He can be reached at reports@wsj.com.  The name of the Church of Jesus Christ of Latter-day Saints was incorrectly given as the Church of Latter-day Saints in an earlier version of this article. (April 29, 2015)
Religious institutions have survived by controlling what their adherents know, argues Tufts Prof. Daniel Dennett, but today that is next to impossible.