When I was a kid, atheists ruled over large swatches of the world and mainstream conventional wisdom expected religion to die out. If Communism (not then acquainted with history's ash-heap) didn't squash faith, then a combination of prosperity and technology would dilute religion into a weak inconsequential tea. Even theologians thought this way: The term "post-religious age" was coined by Dietrich Bonhoeffer. Now, though, the pendulum has swung the other way, and even die-hard non-believers proclaim that "the Golden Age of Secularism has passed." But the death of atheism is being exaggerated now as much as the death of God was 40 years ago, at least according to this study: Using statistical models, it predicts that atheist-majority countries will soon dot the globe, for the first time in history.

That is, of course, just the supposedly ghastly fate that Newt Gingrich recently said might befall the United States: He said his grandchildren could end up living in "a secular atheist country." So it seems the post-religious age has gone from inevitable future to boogeyman in an incoherent stump speech (Gingrich said this awful future secular state might end up dominated by Islamists, which shows you just how seriously he takes this blather).

The countries heading for secularism in this paper's model would make poor Gingrich-fodder: It's hard to picture the Netherlands (already 40 percent irreligious) Australia, the Czech Republic (60 percent God-free) Finland or the Netherlands as cesspools of evil and cruelty. Yet the trends described in the paper also belie the claims of Richard Dawkins and his ilk, that atheists are an oppressed minority all over the world. Today, note Daniel M. Abrams, Haley A. Yaple and Richard J. Wiener, the only religious group that's growing in all 50 American states is "No Affiliation," and census data from 85 regions worldwide, in the countries I've mentioned plus New Zealand, Austria, Canada, Ireland, and Switzerland, show the same trend away from identification with faith.

To explain this, the authors, who are physicists, propose a simple mathematical model, in which society is represented as two groups, religion and non-religion, competing for adherents. Their model fits census data from very different nations, they write, which supports their claim that religious adherence in all places has a single underlying explanation. Which is, they argue, simply self-interest: "The model predicts that for societies in which the perceived utility of not adhering is greater than the utility of adhering, religion will be driven toward extinction."

To get the right number for this "perceived utility"—"a quantity encompassing many factors including the social, economic, political and security benefits derived from membership as well as spiritual or moral consonance with a group," they compared different results of their model with actual data from Finland, Switzerland, Austria and the Netherlands. The model that best fits past data was the one in which faith "will disappear if its perceived utility is less than that of non-affiliation, regardless of how large a fraction initially adheres to a religion." If indeed that's right, then, according to their calculations, 70 percent of the Netherlands population will have no religious affiliation by mid-century.

Plug a different range of numbers into the key variable, though, and the model arrives at a steady state, in which a small social group persists as an island within a much larger group. That, they speculate, was where society spent much of its history, with religious people the vast majority and non-believers a small but constant minority. But modernity changes the perceived utility of religious membership, and that created an abrupt shift from the irreligious-as-stable-minority state to the "religion disappears" state.

Why is all this better than simply projecting current trends forward? Because, they say, they've provided an explanatory mechanism. That lets them be sure that the trend will continue, because it is an instance of a general law, and not a historical accident or coincidence.

The nations that supplied the paper's data are all either European or former European colonies, which means their religious traditions are heavily influence by Christianity, a religion in which conversion counts for a great deal and everyone is reckoned as either a believer or an unbeliever. It's hard to imagine how this model could fit a religion rooted in different principles. Many Jews I know regard themselves as committed to their community but don't believe in God. And for animists, their religion is more of a worldview than a creed they can endorse or abjure. It would be interesting to see how the model fits census data from a non-Europe-derived country.

Still, for those of us who do hope Gingrich's grandchildren live in a secular atheist country, it's an encouraging paper as well as an interesting one. It suggests that even as theists and atheists stage their raging battles over questions that can never be practically answered, a majority in many modern countries will simply drift away. Patience, fellow Godless secularists. Patience!