That religious experiences exist no longer needs proof.
But it will always remain doubtful whether what metaphysics and theology call God and the gods is the real ground of these experiences.
The question is idle, actually, and answers itself by reason of the subjectively overwhelming numinosity of the experience.
Anyone who has had it is seized by it and therefore not in a position to indulge in fruitless metaphysical or epistemological speculations.
Absolute certainty brings its own evidence and has no need of anthropomorphic proofs. ~Carl Jung, The Undiscovered Self.