We are all born atheist. Once I hit my teenage years I became as devout of a Christian as I could possibly be. I went to church, prayed, and all the usual stuff. When I was in 10th grade I met a guy that had no qualms saying things like, “If there’s a Hell — and I highly doubt it — I’m going there.” I remember saying it once, laughing, and then realizing how liberating it was. I realized that all that religion was just me attempting to find myself as a young boy.

After that point I considered myself agnostic, and I remained this way for several years. Though deep down I didn’t believe in the existence of gods, I had this unshakable feeling that something was there, watching my every move and listening to my every thought. No matter what evidence I heard/saw/read, I didn’t see proof of God’s existence. But I also didn’t see proof of God’s non-existence, so it was easy to claim agnosticism. Though I was essentially atheist, my inability to shake that feeling left me referring to myself using an inadequate term.

And then I discovered Carl Sagan.

A friend gave me a copy of Cosmos and I consumed the whole thing in just a few days. Before I’d even finished the first chapter, my whole life had begun to change. It pried my third eye wide open and allowed me to begin my intellectual awakening. Before the year was over, I’d read over 30 books about science, biology, evolution, skepticism, physics, and astronomy, including almost every book written by Sagan. The whole process of rediscovering the beauty of nature and the purity of science didn’t just change my beliefs, it reshaped the way my mind worked. I can honestly say it made me into a smarter, more critical, more humble, and more compassionate person.

Right in the middle of all this, I read Sagan’s Pulitzer Prize-winning book The Dragons of Eden about the evolution of the human brain. Sagan never once told people they should be atheists. What he did was reveal the world to you in a way that made you realize where the whole deity thing comes from. We have always been a part of hierarchies, and we have always had alpha males. I don’t remember the exact line but I do remember the point he made: being part of a hierarchy and submitting to alpha males is an integral part of our biological heritage. It explained why people all over the world and in every culture believed in higher powers, why we elect supreme leaders (almost always male) even in nations that call themselves democracies, and why we literally worship sports like football and soccer.

When I realized that the feeling for God and other higher powers is a naturally occurring aspect of our biology, my whole world changed. I suddenly found that proof that agnostics were always claiming didn’t exist. I suddenly felt that assurance that I’d never felt when calling myself atheist. And, most importantly, I no longer resented religious people for believing in higher powers. Though I don’t wear my atheism on my sleeve (because of the stigma attached to it), I finally have complete confidence in my beliefs. No uncertainties, no doubts, and (most importantly) a sensible explanation for the existence of all spirituality.

I’m not an atheist because I have yet to see evidence that God exists; I’m an atheist because I understand the biological explanation for it.