MikeofNorthumbria said:

"An atheist is certain that no such entity as a "god" exists in our universe."

Not so. An atheist is one who believes that no such entity etc. etc.

There's a subtle but significant difference between belief and certainty. There are many who believe in the existence of God (or a god) but can't prove it. They are still believers. To be an atheist is not to be required to prove a negative; is is enough to believe the negative. Doesn't prove the atheist is right, but simply proves that the atheist IS an atheist.

Dave Oesterreich