Circumstantial evidence is how you disprove a negative. Neither judges nor juries are required to abandon their common knowledge as they enter the courtroom. Neither the Agnostic, nor the Atheist, has ever had a prayer answered. Neither has heard the voice of a god. Neither has seen a god, nor any spirit, nor anything remotely resembling one.
Miracles don t happen.
Plain Old Common Sense. That 600 y.o. Religious claims, then, fail every truth test common to a courtroom. If some evidence pointed to a god, and some against, we could reason that the problem is ultimately unsoluable. These are the reasons why I'm an atheist, and not an agnostic.