My religious family and friends cannot comprehend how I can be an atheist. I, on the other hand, cannot understand how they can be theists and believe things that not only aren't supported by evidence, but also are often contrary to evidence--and irrational, and sometimes unjust and inhumane too.
Earlier today, I posted this comment on the Pharyngula thread, "Why are you an atheist?" I thought I'd re-post it here. The full story of my transformation from questioning, doubting Catholic school girl to confirmed atheist is longer and more complex than what I wrote in this comment, but it's an accurate summary of why I do not believe in God.
I am an atheist because I'm a skeptic and rationalist. I am not a skeptic and rationalist because I'm an atheist.
Even as a young girl in Catholic school, I was one of those troublesome kids who would actually think about what I was being taught in religion class, ask questions, then say, "But...but..." Because so much of what I was being taught didn't make logical sense to me. And did the adults have evidence that any of it was true? They never had satisfactory answers to my questions. I began to suspect that the adults were just making stuff up.
My inability to accept what I was being taught wasn't helped by the fact that I was well-read, especially for a child growing up in the circumstances I did. I just couldn't mesh what I knew was reality with what the church was claiming.
And, so many Catholic beliefs and practices assailed my innate sense of fairness, justice, and compassion.
For a long time I tried, really really tried, to believe, but I just couldn't make the leap of faith. That time in my life was very depressing and stressful.
Finally, when I was 18, in a single stunning blast of insight, I realized that religion was just rules and rituals made up by fallible men to try to control what other people did, and that there was no evidence that God, who allegedly beamed these rules down from wherever, even existed. So I simply stopped trying to believe the unbelievable. That was it. I've never looked back or felt more at peace.
After the day I stopped trying to believe, I described myself to people as a non-believer, or simply said I didn't belong to a church. I didn't realize I was an "atheist" until I started reading Pharyngula.