P1: Atheists claim that they have no belief in God.

P2: In order to have no belief in God, a belief in God could not be known to exist.

P3: Since a belief in God is known to exist, then the Atheistic position is a Theistic position that is against a belief in God or not a position at all to assess.

C: If its a Theism that is Against Theism, then its self defeating and false. If its not a position in regards to religion, we need not be concerned about it since it does not exist.