Does it makes sense to pray if God's existence hasn't been rationally proven independently of faith? Does the meaning of the practice of praying depend on philosophical proofs of God's existence?
I agree with Professor Leaman. I might only add that today most theists do not traffic in "proofs" for God's existence. There are very few, if any, universally acknowledged proofs in philosophy. These days, we more often simply refer to good or bad arguments. It also might be added that hope is often identified as a virtue in some religious traditions, and hope may well serve as a sufficient ground for prayer, even when actual belief is not in play.