No, atheism does not flat-out reject the idea. Atheism is the disbelief in the existence of a deity, but it does not indicate one feels certain of its nonexistence. The vast majority of atheists, myself included, are agnostic atheists. I find the idea of a deity absurd, but to claim I have absolute knowledge on the matter is even more absurd. Agnostic is incorrectly applied to this poll, as it is not a belief system unto itself. You are either an agnostic antheist or an agnostic theist. Most self-defined agnostics that do not refer to themselves as either atheists or theists are in fact agnostic atheists, as they do not believe in a deity.