You can learn theories, Vedanta, Tantra, Sankhya, all the Shastras, but unless there is a change in the mindset, there is no possibility of understanding what is being said, because the average mind, which is stuck in its own images, and its own system of thought processes is not ready to touch that which is beyond the grasp of even the senses. So the mind has to be opened and de-conditioned and sadhana is the way to do it.