The path of mysticism extraordinary yogic experiences visions of God requires sadhana. Advaita Vedanta says not even that you just need to pay attention to the experience you are already having. The whole discussion was how can we make these spiritual experiences acceptable to modern science, neuroscience, cognitive science and all? It's like a person who Upanishad says this the person who passes over buried treasure so there is gold or jewelry buried underground and you pass over it again and again in search of that treasure but you never find it.