I am an atheist because God called me to be a minister and then killed my mother with a car.
Well, sort of. I grew up in an evangelical Christian home with two parents who had been converted to this form of Christianity more or less as adults. They had both been to church as children, I believe, but the serious, born again and baptized commitment came later. I have a theory supported almost exclusively by anecdotal evidence that says adult converts dive into religion with much more ferocity than those who have inherited it as a vestigial appendage that they acknowledge but rarely think about.
We went to church with a regularity that I find hard to believe now. Twice on Sundays, Wednesday nights. Plus my parents were the sorts of pillars of the local church that every small church has. They served on the church board. My dad was the Sunday school superintendent and led the choir. My mom was active in all sorts of children's programs and women's ministries. This meant that in normal weeks we'd be at church at least one more weeknight and probably on Saturdays for some function or another. It was pervasive.
I never really gave much thought to the tenets of Christianity but simply accepted them as obviously true as I'd been taught, despite being extremely curious about other things. It just didn't even dawn on me as something to think about. The ability of religion to bifurcate the mind and place itself in the side that contains the unquestioned assumptions about the world is amazing.
Then in high school, I had two related experiences that started to pull me in opposite intellectual directions, but in the end would conspire to build the exit from faith. First, I began reading philosophy after being introduced to Plato's Republic in high school American Lit.* Reading Plato opened me up to the idea that what we think we know might not be the case after all. The world of appearances--the world we simply assume to be just like it seems--might be very different indeed. This started me thinking about God in more seriousness, which prompted the second experience--I "felt called to the ministry."
Anyone who grew up in an evangelical setting knows what a big deal it is for someone to "feel the call." You become a kind of a local celebrity. But more important for me, it was what I thought the very serious people who think about very serious things do. There was really only one example in the church that I could see who really dove in deeply to the issues I thought were pivotal to understanding God and the universe, and that was our pastor. He had the job where you think about things, so I convinced myself that this was the job God had planned for me. I started reading what theology was available to me--CS Lewis, AW Tozer, this horrible doorstop called God, Man, and Salvation--but also more Plato and other things, particularly Ralph Waldo Emerson. I started to think about how the versions of the relationship between God and the world expressed by Platonism and Emerson's transcendentalism differed from the one presented by my religion, and how I needed to understand other visions of the world to effectively argue for Christianity.
My first year and a half of college (at a Christian college**, of course) I took mostly religion and philosophy courses and decided to major in philosophy, realizing that the questions I had about religion and the universe weren't even the most fundamental problems facing Christianity. I'd need the tools of careful argumentation and reasoning to effectively deal with the big issues, because I'd started to struggle to make sense of the core concepts of Christian theology. What am I supposed to do with the idea of the Trinity? How does the death of Jesus satisfy any concept of justice in the idea of the Atonement? How can God's future knowledge be reconciled with human freedom and moral responsibility? How can we claim God is good when there is so much needless suffering? No satisfying answers were forthcoming in my reading, but I thought I'd figure it out. There wasn't any urgency.
Then four days after Christmas my sophomore year my mother hit a patch of ice on her way to work, slid through a stop sign and was killed in a car accident. What immediately struck me in the aftermath was not the question of why God would allow this to happen--I'd already learned that the problem of evil was a philosophical knot I'd need some time to unravel--but rather the oppressive absence of God. I'd always been told that God would be there as a comfort in terrible times. We may not know why God allowed bad things to happen, but we could be assured he would be a strengthening presence when they did. He'd help us get through them.
Well, he didn't. I prayed and cried and begged and pleaded and got nothing. Obviously I was to blame, though. God was good, so lack of understanding or lack of faith or something I was missing kept me from experiencing that blessed assurance I was supposed to feel carry me through this tragic event. I just had to be missing something. This provided me with the urgency to really understand Christianity. I spent the next few years trying to understand, reading everything I could in search of the key to understanding and faith that would make the absent God present. But the more I studied and thought the less sense it made. All the confusing concepts were all knitted together, so that if you think you've made sense of one part of it, your answer doesn't connect back to another, and it leaves a hole you have to patch elsewhere.
Eventually the string I pulled that unraveled the whole theological sweater for me was the idea of the Atonement. I came to the conclusion that there is simply no way of framing the Atonement so that Jesus dying on a cross is either necessary or sufficient to absolve me of responsibility for immoral actions. And if it's neither necessary nor sufficient, then it has to be arbitrary, which means it doesn't work as an explanation for why Jesus would have to die. After deciding that the death of Jesus couldn't do what it was supposed to do, the rest fell apart rather easily. If there's no Atonement, there's no need to try to figure out how original sin is possible without a real Adam and Eve. If there's no original sin, then there's no need to denigrate human capacities like reason and moral sense, so we don't have to take the moral theory or metaphysics required for theology as revealed to us to give us knowledge in our fallen state. If human reason and morals aren't compromised in this way, then we don't need faith as another way of knowing.
And once you jettison faith as a legitimate way of justifying belief, well, the rest of the ramshackle structure just comes right apart. When you require arguments from known premises or empirical evidence to justify holding beliefs, all of the other propositions of religion are found wanting. The arguments for the existence of God are miserable failures. The evidence for the existence of God is, well, nonexistent.
*Yeah, weird, I know. We read it because our teacher wanted us to think about how fire symbolized knowledge or illumination in Huckleberry Finn. Or something.
**As an aside, the dashing and eloquent Ken Ham spoke at my college my freshman year, and to the institution's credit, a panel discussion was called the next day with members of our faculty to refute Ham's science, theology, and logic.
^I sent this to PZ Myers for his "Why I am an Atheist" series at Pharyngula, but I don't know if he'll post it there, so I'm posting it here.