You: An omniscient human would not be perfect. Such a person would know things better left unknown, like the feelings of others. That would make life almost unbearable.

Aaron: That proves that a perfect person cannot exist, not that God does not exist.

You: My perfect person would have to have the quality of existence to be perfect. If you are willing to admit that the perfect person might not exist, then you must be willing to admit that God might not exist.

Aaron: I will admit to no such thing.

You: Then I suggest you try harder to prove that God exists.