One of the great confusions of modern life is caused by the presentation of prediction as established fact. I quote from the beginning of the Pew Research Center’s The Future of World Religions: “The religious profile of the world israpidly changing…” (emphasis added). We are then told that by 2050 that Muslims will equal Christians, even while atheists, agnostics, and the unaffiliated will decline, Buddhism will remain about the same, India will have the world’s largest Muslim population, Christians in America will decline and Islam will surpass Judaism in the percentage of US population, and finally, almost half of the world’s Christians will live in sub-Saharan Africa.

The overall implication, boiled down, is this: in 35 years Muslims will equal Christians; in 36 years Christians will be in the world minority; and in, say, 100 years, Muslims will be an overwhelming majority. That will make it a very different world. Very different.

Is this all a fait accompli, a glimpse of the inevitable future? Is this what will happen, or what could happen given Pew’s reading of current trends?

If it is the first—and that’s how most people understand such pronouncements, as if they were divinations about the future—then what will be, will be, and there’s nothing anyone can do about it. If it is the second, then it is not a prediction but must be taken as a warning—especially to Christians—and there’s something that can be done about it.

On this difference, the actual future hinges.

That, I suggest, is why the Old Testament so roundly condemns all sorts of divination (Dt 18:9-14). The severe condemnation was put in place to protect the freedom of the will from the poison of fatalism. There is all the difference in the world between a warning (If you continue to drink, then your wife will leave you), and an inalterable fact-to-be (In three days, it will be the autumnal equinox). Short of the universe imploding, the second will happen. But the first can be avoided if the husband chooses to do what will keep his wife from leaving: giving up the bottle.

In the modern world, we’ve come to believe that human events are exactly like celestial events: there is an equally exact science of prediction for both. This confusion is the result of accepting the notion that everything is made of matter—human beings and planets alike—so that we can equally well predict the actions of both.

Hence the rise of the social sciences that try to imitate physics and chemistry in presenting numerical data that (allegedly) predicts the actions of human beings in the future from the actions of human beings in the present. With the floor-to-ceiling determinism of materialism, there is no room for “if,” no room for a warning, because what is going to happen is going to happen.

All of this is to help us understand what the Pew “data” is actually telling us—and here, I speak as a Christian to Christians.

Imagine a Pew The Future of World Religions being published in, say, 50 AD, or 100, 200, or 300 AD? In the first, Christianity wouldn’t even register. In the second, it might be a tiny blip (about 10,000 total Christians. By 200 AD, it would appear to have grown significantly (perhaps 200,000 adherents), but in relationship to other world religions it would be inconsequential. And moreover, since it was subject to persecutions, it would best be predicted as shrinking, especially since it was an enemy of the world’s most powerful empire. In 300 AD, Christians were 10% of the population of the Empire—still not very formidable percentage-wise—but they were about to undergo some of their most severe persecution at the hands of the state. Thus, the future did not look very promising.

But then the unpredictable happened. With the conversion of the Roman Emperor Constantine in 312 AD, persecution ended, and Christianity came to be protected. Christianity was on its way to becoming the world’s largest religion—something that could not have been predicted from any of the hypothetical studies at 50, 100, 200, or 300 AD. Or for that matter, at 400, 500, 600, 700…

Christianity grew for two main reasons. First of all, Christians understood that they were commanded by Christ Himself to evangelize the world: “Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you” (Mt 28:19). Second, Christians were passionately devoted to the family, taking with the greatest seriousness that the union of male and female was made by God to be permanent and to be blessed by having children. Unlike the Roman pagans, Christianity rejected contraception, abortion, infanticide, and divorce.

In short, Christians grew by making converts and (pro) creating more Christians.

That brings us back to the Pew study. According to Pew, the projected changes in the number of adherents to Christianity and Islam are caused primarily by “differences in fertility rates and the size of youth populations.” Muslims have more children. More children raise the size of the youth populations. Conversions bring in even more youth, who are offered a compelling religious vision.

That brings us back to the two primary reasons why Christianity grew unpredictably large in the Roman Empire: differences in fertility rates and the size of youth population. Again, the first Christians had large families, just as large as Muslims have today. Their children filled the churches, and, along with new converts and their families, brought the churches to overflowing. The Good News was declared as the Best Possible News, and not just old news. There was no “greying” of the early church, as there is of the church today.

So, what the Pew study gives us is not a prediction—unless of course, Christians are content to be content.