Is atheism a belief?

[bennyboy]

Atheism is not a belief, positive or negative. Just like someone who knows that the earth is round does not merely believe that the earth is round.

That may be true, but we don't normally declare ourselves 2+2ists or round-earthists. Whatever else you say, an -ism isn't normally taken as a description of state; it normally refers to adherence to some system of thought, principle or organization. I understand that in the States, saying you lack a religion is probably worth saying, so what I call soft atheism means something. But it's certainly not unreasonable when religious people encounter you that they will think that your "-ism" means that you subscribe to a belief system of some kind.