I‘ve run into a paper by Eric Kaufmann, “Shall the Religious Inherit the Earth?: Demography and Politics in the Twenty-First Century,” that gives an interesting twist to the debate about secularization.
Social scientists have been butting heads for quite some time about secularization, counter-trends of religious revival, and so forth. Kaufmann thinks there’s a new element that affects the picture. Many religious movements today emphasize a pro-natalist morality, and outreproduce more secular populations. They are more resistant to secularizing and population-limiting pressures than traditional believers in more premodern societies, since they put more emphasis on choosing a faith-based way of life, rather than just taking faith for granted because that is the social norm. And their growth rates more than offset defections to secular surrounding cultures. So Kaufmann speaks of a “second demographic transition”; he expects secularizing trends will plateau and be reversed even in Europe, over the long term.
The basic point is sound enough. Cultures have to reproduce themselves, and this correlates closely with biological reproduction. Secular moral orientations predictably lead to less than replacement level reproduction. (A damn good thing, if you’re worried about the environment.) So if secularization is to represent a growing trend in the human population as a whole, it must depend on large-scale defections from previously religious populations. But it’s perfectly conceivable that there can arise new, modern variants of religiosity that both biologically and culturally reproduces at a high rate. These variants would then come to represent a dominant form of religiosity at the expense of more traditional or lukewarmly religious populations. Eventually, by sheer force of demography, they can become dominant in the human population at large.
Mind you, since we’re already well over the carrying capacity of the planet, this scenario is unsustainable. So if I wanted to make a really long-term prediction, I’d expect civilization to collapse, which would totally wipe out secularists and leave the field, such as it is, to the most committed kind of supernatural believers.