"No reasonable dialog between theists and atheists is possible until the myth of positive atheism [which "positively affirms the nonexistence of God"] is put to rest once and for all. When the theist portrays atheism as necessarily irrational because no one can prove the nonexistence of God, he is attacking a position that has rarely been affirmed by real atheists."Honestly, I wonder how Smith went about collecting his sample of "real atheists," because there are plenty of atheists that actually affirm the nonexistence of God. I would like to go on record as one of them.
The reason is very simple. The usual definition of God is an omnipotent, omniscient, omnibenevolent being. This, as I have explained, predicts a perfect world. This prediction overwhelmingly fails, making the God of high theology one of the most overwhelmingly disconfirmed hypotheses in the history of hypotheses.
I should qualify, though, that I do not claim to be able to offer evidence against any sort of God that you could think of. For example, it is utterly impossible to offer evidence against the idea of an omnipotent being with totally mysterious motives. No matter what happens in the world, this being might have done it (since he can do anything), and he might have wanted to do it, since his motives are mysterious. It cannot be disproven, because it does not tell us anything about the world of our experience, but I think that very fact is reason not to take the idea seriously. Such a God would be, at best, metaphysical fluff. Whether we should actually deny the claim is a trickier problem. The idea is a very similar idea to a number of patently absurd ideas, such as the idea that there is an invisible, incorporeal dragon that spits heatless fire in the room I'm renting for the summer. I have trouble entertaining an idea, but I am not sure it would be right to deny it. However, I might ask Carl Sagan's question: what's the difference between such a dragon and no dragon at all? Similarly, there is arguably no difference between an utterly mysterious God and no God at all.