Then John P, what is the source of your rationality? All of science is "I don't know" "But here is the best theory we have so far."

Simple. In either a scientific sense or a non-scientific sense, I've never been given any reason to so much as entertain the possibility that gods exist. There is no real theory that supports the idea, so it's not a question of "the best theory we have so far", but rather, "why would anyone believe such a thing?" It is, of course, impossible to prove a negative, but there should be a least some evidence -- scientific or otherwise -- or logic behind a proposal for it to even be on the table. The possibility of there actually being a god is so remote that I'm comfortable saying there is no realistic chance.

From the standpoint of saying either "this is possible" or "the chances of this are so remote that we may as well say it doesn't exist", there is no difference between an agnostic and a believer.