Do you mean 'The fact that we don't know whether or not there is a god, proves that there must be'?
I'm pretty sure he does not mean that, but he may feel free to correct me. I got the impression that he meant, "If there were a God, we wouldn't be able to prove it anyway."
I think it was the whole
precludes conclusive knowledge
thing is what clued me in.
-Erasmus
You hit the nail on the head.
I look at it this way:
Let's say someone (let's call him Pat) told an atheist (let's call him Jean-Paul) that God had revealed Himself to Pat. Now, something that would convince Pat and Jean-Paul of the existence of God would have to be pretty extraordinary, right?
Right.
And the thing is, something that to Pat indicates the existence of God could very easily indicate to Jean-Paul that Pat is having terrible hallucinations. In short, how do you prove that God revealing himself isn't something else?
Of course, it works the other way, too. Let's say that Jean-Paul tells Pat that he has conclusive evidence that God doesn't exist. Because God is, theoretically, an all-powerful being, Pat can easily say that God simply planted that evidence for Jean-Paul to find as part of His infinitely complex plan.
So this is why I'm an agnostic. I vote that I don't believe in God not because I feel that it's impossible for God to exist. Rather, it's because there isn't any particular reason to believe in God that doesn't also apply to, say, unicorns.