The long-term prospects of the nonreligious

Is it really likely that Christianity will crumble and fall to increasing secularization and the looming tide of atheism?

Let’s do a little “systems thinking” here. Within the global population, we have a number of pools. Let’s consider that we have the “religious” pool – which is everyone who is affiliated with a particular religion – and we have the “nonreligious” pool – which is everyone who says “there’s no God, or we can’t know if God exists at all” (e.g. nonreligious and atheists).

We can immediately see these two pools are mutually exclusive, at least at the functional level. You can’t say “God doesn’t exist” and yet be a Christian, for example. Now, at the “technical” level you could have a person who is becoming nonreligious within a Christian church – but he or she is already “functionally” a nonreligious and sooner or later will likely defect.

So how do these two pools grow? As with any systems based on populations, they grow by birth and conversion. People are born into families that are already within the system (e.g. Christian families, or nonreligious families), or by people who leave one pool for another (they “defect” from the Christian pool and “convert” to the nonreligious pool, for example).

Globally speaking, is that nonreligious families have fewer children on average than Christian families. (The difference is less stark in more developed economies where everyone’s having fewer babies, but it is present nonetheless.) The nonreligious gain members by defection from other religions (secularization in the United States, and Iran, and other places)–but they also lose members through conversion to religions.

Christianity (and other religions) have more children than the nonreligious, so the religious have an advantage there. Although we lose members to defection, we gain from conversion (-12 to +15 million people per year), so we have a net advantage.

The upshot, globally, is that the nonreligious are growing at a rate of 0.33% per year (and atheists at 0.2% per year) while Christians are growing at 1.32% and Muslims at 1.8%.

Now, these are global averages over the past ten years. Smaller situations – for example, America, or Iran – could see different growth rates, particularly over a yearly period. Smaller still, individual denominations could find themselves losing large numbers of people to aging or secularization. These small situations and outliers, however, do not represent the overall regional or global trend. The trend toward nonreligious is not overwhelming the trend toward religion. Our world is growing more religious, not less.