<human>:  Why does Bush think that the existence of God is a delusion?
<bot>: Bush argues that there is no evidence for the existence of God. He says that the existence of God is not necessary for explaining anything in the universe, and that the concept of God is just a metaphor for a more general concept of a creator. He says that if we assume the existence of God, then we must explain why there is no evidence for God. He says that the existence of God is not necessary to explain the universe, and that the existence of God is a delusion.