(this is not that great a post, but hey: I’ve gotta start this thing somehow)
According to the venerable Wikipedia institution, “Atheism is, in a broad sense, the rejection of belief in the existence of deities. In a narrower sense, atheism is specifically the position that there are no deities.”
For a good chunk of my undergraduate career, I would have identified as an atheist, although I was really more of an agnostic in thought. The way I figured it was that I lived as though God didn’t exist, so “atheist” more properly signified my mode of existence than agnostic (I had, and still have, something of the existentialist in me).
A good part of what caused me to change bases was a tension in my thought: on the one hand, my growing belief that the universe is a rational and completely understandable place as well as my growing belief that it is absolutely insane – or at least that we are insane. The former covers my adoption of classical theism (I was impressed by it even in my more nominalistically inclined days) while the latter my growing Judeo-Christian religiosity. Broadly speaking. Giving a decent explanation for why I ultimately wound up a Catholic would very quickly expand into a sort of autobiography, as I think that a variety of different experiences and influences in my life so far helped to prep me to make that decision.
The paradox needs to be held in tension; any attempts to dissolve one into the other do a disservice to reality and are doomed to crash and burn.