+1
The atheist assumes nothing. The theist says "we believe in God" and tries to explain. The atheist isn't convinced.
The atheist does not say with 100% certainty there is no "God" - the atheist simply says "show me."
The theist says with 100% certainty that there IS a "God" - then says "prove to me that I'm wrong"
The atheist says, it's not for me to prove anything, I didn't say there was a "God" in the first place.
OK. In my question to get my mind wrapped around the terminology, let me offer an example: I have a colleague who has a doctorate in philosophy and teaches doctoral courses in the philosophy of science. He knows his stuff. Philosophically, he assumes materialism (i.e., not dualism). IOW, he believes matter is all there is, hence, in his mind a spirit (a necessary component of many faith traditions) cannot exist. He's an atheist, but he makes assumptions that define a playing field.
I'm not saying you do that, or are trying to do that; but, I wanted to keep in play that at least some atheists (in my experience) to make assumptions that define the field on which they play. Or would you say he's not actually an atheist, because he does make a philosophical asumption about the world?
I've got to run...car needs an oil change. I've very much enjoyed following this discussion and look forward to returning to it later! <insert hat tip to all>