I have often made the argument that religiosity, a personal belief in god, spirits, the supernatural, etc., would emerge in human societies on its own if it wasn’t there already.

Imagine taking an entire generation of people in a geographically isolated region, and wiping out their memory of religion, and also, removing all references to religion that they might ever encounter. They would be religion free for a while, maybe even for a number of generations, but eventually, they would reinvent it.

Everybody has a theory of why religion exists, what purposes it serves, etc. etc. Until proven otherwise, I will assume that these “functions” are all post hoc. Religion may serve one or another role in a given society or culture, but I’m going to assume that religion was incorporated for this purpose after the fact, not developed, evolved, or inserted for this purpose. I may be wrong, but until I see compelling evidence to the contrary, I think it is the safest assumption.

Why would religion (using that term very loosely) emerge in a non-religious human society? Because of lawnmowers and dogs, or dreams or delusion, mainly.

One day I was driving down the street and I witnessed a dog transform into a law mower. How could that happen if there was no spirit like force beyond some kind of veil that usually clouds our perceptions, hiding from us things that defy physics most, but not all, of the time? The only way to explain this is to invoke some sort of religious thinking, right?

Here’s what happened. It was a bright sunny fall day. Warm. It was a densely populated residential neighborhood. Families were out, parents raking leaves and the kids jumping in them, dogs running around, children playing ball. I was unsure of where I was or where I was going (I was not familiar with the neighborhood), scanning back and forth for street signs and house numbers. The sun was low enough to be causing a lot of glare. So, I was paying a lot of attention to my peripheral vision (looking for a kid running into the street, or a dog not seeing me coming). Off to my left, I saw a large dog sitting on a lawn. I glanced to the right, then back to the left, and now saw that the dog was a lawn mower with someone’s coat draped over the handle. Miraculous transformation of a spirt being!

Or, a simple mistake.

And that, of course, is how I would actually explain what I say … a trick of the lousy light in a confused tapestry of activity that I was not initially paying much attention to.

We experience things in real life that can’t be true, now and then. We usually but not always explain them, but sometimes we explain them with “I don’t know what that was, but it is not important… just a trick of the light.” But say I was a young and impressionable youth searching for meaning in life, and I had just seen a talk given by a spiritualist who claimed that spirit dogs occasionally appeared out of nowhere, transforming from inanimate objects into a large dog, then back again. Well, if that has been the case that day, perhaps I would have started worshiping spirt dogs, and I would never look at a lawn mower quite the same way again. If the spirit dog belief was a growing belief in my subculture, a belief held by community leaders, respected individuals, potential mates, and family members, I might be even more likely to break that way. And so on. You get the point.

The current National Geographic Roundtable asks the question, “Is belief in God innate in our brains, as if it were installed by some divine programmer? Or is spirituality a more complex evolving adaptation that has both helped and harmed us as a species?”

Neither, as stated. It is not innate in our species, as people usually understand the term — coded for by genes, the inevitable outcome of typical development. But I said it would always emerge in human societies, right? Yes, but not because it is innate (built in) but because the process of human behavior in the context of our physical world and culture would prod and poke and hint and push until it started to emerge here and there, and eventually, it would become part of the larger system of behavior. And no, of course, a tendency to eventually develop religion in a society was not put there by a divine programmer, any more than a paisley tea pot was set into orbit around the Planet Jupiter by a mischievous flying unicorn.

Yes, religion, spirituality, and all that, is a complex changing thing that may have helped and may have harmed. But is it an adaptation? No. It is a side effect.

That’s my story and I’m sticking to it. But to get a different set of perspectives, check out The God Brain, which premiers Feb 21st at 9PM Eastern on National Geographic.

Host Jason Silva travels to Jerusalem, Israel, to explore, “The God Brain.” Fascinating new research has uncovered the possibility that believing in God may be hardwired in our brains. Is this because a divine power greater than us installed this software? Or is it possible that the believing part of the brain has evolved over thousands of years as an evolutionary adaptation that helps us succeed as a species. Physician and neuroscientist Andrew Newberg of Jefferson University Hospital has spent decades exploring the neurophysiology of religious and spiritual practice. Dr. Trevor Cox from the University of Salford, an expert on sound perception, explains how you respond to different musical keys and music played in churches. Dr. Jennifer Whitson of UCLA focuses on the psychological experience of control and sheds light on how to make sense of the environment and inexplicable events. Dr. Bruce Hood, an experimental psychologist at the University of Bristol, will demonstrate that even the most nonbelieving brain can have unconscious biases, which are fundamental characteristics for supernatural thinking.