More than eight in ten people worldwide have some sort of religious belief, according to a Pew Research Center study. Approximately one third of those people are Christian.
Even though the percentage of people who identify as atheist is on the rise, the world is an overwhelmingly devout place.
And while science versus religion has been debated since classical antiquity, we're still a long ways off from definitively knowing how and why the human species came to attribute its existence—and the creation of everything in the universe—to spiritual entities we cannot see, and cannot prove to be real.
One theory, as illustrated in this short video from New Scientist's Explanimator series, presents the possibility that religion emerged a long time ago as an evolutionary adaptation. According to this argument, early forms of organized religion were necessary for the building of clans that helped to ensure the long-term survival of large groups of people. Religion encouraged clans to unite around a shared belief or ritual, and allowed for the cultivation of community practices like foraging for food, hunting, and sharing childcare duties. These things would have given religious groups a key advantage over their competitors.
So as these clans continued to thrive and survive, their genes were passed on, and religion was selected for by evolution, according to the video. Clans, over time, grew into large communities that supposedly benefited from the stability that a shared faith provided, until religion eventually appeared in some form throughout every human society.
No matter how we ended up like this, our brains do seem biologically wired for religion, the video adds. "Many think our brains evolved to assume that things that happen in the world have a purpose, and if that purpose is mysterious, perhaps an unseen supernatural agent is at work."
The argument here is that humans are "strongly attracted to explanations of events in terms of agent action—particularly events that are not readily explained in terms of ordinary causation." Existential threats scare us, and we desire tools that help us reason with them.
Religion is therefore much like language. Humans aren't born with an innate knowledge of French, English, Chinese, or whatever. But we are born with the ability to learn those languages based on the societies into which we are born or raised, the video adds. They help us to make sense of the world around us. Likewise, none of us are born believers, but we can pick up our faiths depending on whether or not we're raised to believe.
It's pointed out that religion came to be so diverse because of the different needs of different types of societies. Agrarian tribes, for example, believed in gods that represented the things they found important such as crops, water, or fire. While larger, sedentary civilizations often worshiped entities responsible for protecting elements like human affairs.
But the larger these communities grew, the less they relied on the benefits that religion once provided, says the video's narrator. Currently, the biggest and most stable societies have the lowest rates of religious belief, according to New Scientist. Safety, they theorize, puts gods out of a job.
Of course, there's also the opposing theory that God does, indeed, exist. But as Carl Sagan once said, "extraordinary claims require extraordinary evidence."