Demography has very probably been a factor in religious history all along. The Concise Etymological Dictionary of the English Language (a favorite book of mine) tells us that our word “proletarian” derives from the Latin proles, ”offspring”: A proletarius was “a citizen of the lowest class, useful only by producing children.” One may modify this rather unsentimental description by saying that children were just about the only cherished possession of people in this class. Insofar as many intense religious movements, at least initially, appealed to poor people, this naturally gave a demographic benefit to religion. The historian Philip Jenkins has been influential in his description of the massive demographic shift of contemporary Christianity from Europe and North America to the developing societies. Todd Johnson and his associates have labored for years to produce the Atlas of Global Christianity (2009), with a wealth of demographic data. A useful summary of the demography/religion connection is provided by a book just published, Shall the Religious Inherit the Earth? by Eric Kaufmann (who teaches politics at Birkbeck College, University of London). Despite the jaunty title of his book, Kaufmann is a careful scholar, not given to wild speculation. But he answers the question in the title with a cautious yes.

Social scientists frequently make predictions. Most of these turn out to be wrong. When demographers make predictions, they have one advantage: barring some catastrophic intervening events, such as epidemics, natural disasters, genocide, the demographic future is already present. To see this future, one just has to visit maternity wards and primary schools. Kaufmann makes ample use of this advantage.

The overall picture is quite clear: the more intensely religious have more children. It helps if such intensely religious groups are physically concentrated and thus protected from outside influences. Thus, while the United States is a strongly religious society, there are also strong pluralistic forces that tend to moderate religious intensity. Therefore, high fertility is not enough for fundamentalists to proliferate; they must also have a high retention rate. Some succeed in this very well. Old Order Amish still tend to congregate in rigorously segregated communities. They numbered about 5,000 in 1900; they number close to 250,000 today. Conversions to this religion are very rare. The retention rate is very high. (One can see why. If you have spent your childhood riding around in horse-drawn buggies, wearing 18^th-century clothes and speaking Pennsylvania Dutch, apostasy would be a difficult option.) Mormons, of course, are much less concentrated physically. But they do have a homeland, where they are more intensely present than anywhere else. In 1920 Mormons were 60% of the population of Utah; today they are over 75% —this despite large migration of non-Mormons into the state. Unlike the Amish, Mormons successfully convert, especially outside the United States (of the estimated 12 million Mormons in the world, 6 million are in other countries). But Mormons also exhibit the two demographic positives of high fertility and high retention.

Ron Inglehart and Pippa Norris, who have done many cross-national surveys of changing values, claim that religion declines with rising affluence. In that case, there would be a race between religion and high fertility on one hand, and socio-economic development on the other hand. I have some doubts about this. As the Mormon example indicates, intense religion and high fertility seem capable of surviving a good deal of affluence. Be this as it may, there is little doubt about a global correlation between intense religion and high fertility. American Evangelicals are proud of having “a full quiver” of children as compared with their non-Evangelical neighbors, and there is even a Quiverfull movement advocating this procreative enthusiasm on Biblical grounds. The Catholic church in the United States would be in much worse demographic shape, were it not for the healthy influx of pious Latino Catholics (despite the inroads of Protestantism in that population). The Muslim world is an outstanding case of high fertility, which seems to survive in America—Muslims are projected to overtake Jews in 2020. In Muslim-majority countries radical Islamists, compared with their more  moderate coreligionists, have a Quiverfull profile of their own.

The most dramatic case in Kaufmann’s book is Judaism—in Israel, in the United States, and probably in Europe. The title of one of his chapters is “The Haredisation of the Jewish World”. Haredim (from the Hebrew haredi/”one who trembles”—presumably from awe) have phenomenally high fertility and retention. The demographic future of Israel will be shaped by low fertility among secular Jews, declining fertility among Israeli Arabs, and exuberant fertility among Haredim. The latter are now projected to be a majority of Israeli Jews as of 2050. This future is already clearly visible in primary schools today. Even more surprisingly, Haredim are estimated to be a majority of American Jews, also by 2050.

Why do Godders (aka intensely religious people) have so many children?

One has to be careful before one attempts any explanation that would apply throughout the world. Most pregnancies anywhere are unplanned, the unintended consequences of sexual activity. This, of course, is especially the case where contraceptive resources are unavailable. And in places where there is high infant mortality, it is only rational to have many children in the hope that some will survive. What, I think, needs special explanation is intended parenting among people who have ready access to contraception (and, if that fails, abortion), and who may have every expectation that their children will grow up into adulthood. This is a stipulation that pertains to most people above the underclass in developed societies. As I write the next paragraph, I am thinking of reasonably affluent, college-educated, American Evangelicals I know.

I will venture a hypothesis. Religion has always given its adherents a sense of living in a meaningful universe. This protects individuals from what sociologists call anomie—a condition of disorder and meaninglessness. Religion, by the same token, gives a strong sense of identity and confidence in the future. More than anything else that human beings may do, the willingness of becoming a parent requires a good measure of confidence in the future. Mind you, this is not an argument for the truth of religion. Illusions may also bestow meaning and confidence. But my hypothesis offers an explanation for the ubiquity and persistence of religion.

I am not sure whether this function of religion works in the same way in the Abrahamic traditions (Judaism, Christianity and Islam) as in the religions to the east of the Muslim world, notably Hinduism and Buddhism. It probably does. For a believing Jew, Christian or Muslim, the future of the world, his own future, and that of his children lies in the hands of a compassionate God. Every mother, of any faith or of no faith at all, will get up in the night to comfort a crying child. She may not speak. Her presence and her holding the child may be enough comfort. If she does speak, it is likely to be some variation of saying “everything is all right” or “everything will be all right”. This may well be true at the moment. In a purely secular perspective, these formulas are finally not true. The mother, the child, and everyone and everything they care about are fated to perish. Religious faith gives a cosmic validation to the mother’s comforting words. It is no accident that the most famous lines of Julian of Norwich, that elusive medieval mystic, are reminiscent of a lullaby: “And all will be well. And all will be well. And every manner of thing will be well”.