You're confusing agnosticism with atheism. Atheism claims direct knowledge of God, namely that He does not exist. Agnosticism on the other hand is the position

You're confusing agnosticism with atheism. Atheism claims direct knowledge of God, namely that He does not exist. Agnosticism on the other hand is the position that the question cannot be answered. Plato and Aristotle's position was one of agnosticism, not gnostic atheism. By the way I consider the agnostic position to be entirely intellectually honest and defensible. I happen to believe otherwise, but a reasonable person can reach the agnostic position.