Recently, daughter.2 asked me why I was an atheist rather than an agnostic.
Good question. Very good question. An agnostic is someone who doesn't know whether a god exists. An atheist is someone who either lacks belief in any god, or believes that there are no gods (the two positions are subtly different). Both positions are, of course, anathema.
For a long time, I didn't really think carefully about this issue. I knew that religion was a waste of time, but since I have no way of proving the absence of god, I called myself an agnostic. But now I think differently.
Here's the argument. What is your position with regard to the Tooth Fairy? Would you all yourself agnostic or atheist? Strictly speaking, I don't see how you can prove that the Tooth Fairy doesn't exist. So, strictly speaking, you should be agnostic. But I think that most adults would come down with a firm belief in the non-existence of the Tooth Fairy, they are Tooth-Fairy-atheists. This is because the whole thing is really absurd. Or maybe you have your own reasons for being Tooth-Fairy-atheist.
Now a slightly more difficult question - what is your position with regard to Jove? Odin? Zeus? Jehovah? Yahweh? Again, strictly speaking, you cannot prove the non-existence of any of them. And yet, your personal estimate of the probability of most, or all of them existing is sufficiently close to zero as to be infinitesimal.
An infinitesimal isn't quite zero, but if you name any quantity, an infinitesimal is smaller than that. I well remember many mathematical proofs that start with "Given epsilon greater than zero, no matter how small, there exists delta such that delta is smaller than epsilon ...". And that leads, inevitably, to calculus which I regard as the most beautiful area of maths.
So, given the possibility of a Tooth Fairy, no matter how small, there exists the possibility of a god that is even smaller.
And hens, as Socrates used to say when addressing his chickens, I'm an atheist.