What is energy? Its transformations are known as sound, light, heat, and so on. But these are only appearances of something else. One never catches an isolated pure energy-in-itself. It is about as detectable as pure matter. There is therefore something behind energy and behind intellect, or shall it be said, behind life and behind thought. Energy cannot be reconciled with an eternal state. But if energy itself springs up as an emanation from the deeper level of mind it may be possible to effect such a reconciliation. Neither intellect nor energy can be the eternal soul but both could be ever-changing emanations of something which might itself be relatively changeless. Light is the highest of the energies; the Sun is the father of all things. Matter is scientifically reducible to light. In the depths of some mystical experiences one may find oneself surrounded by an ocean of light. Light is then the manifestation of this deeper mind but it is still only a manifestation. Consciousness must be interiorized so deeply that even a thought or an idea, a psychic image or a clairvoyant vision must be recognized as something outside the true being, something objective, separate, and away from the true self. Many mystics do not feel such a need, but all philosophic mystics ought to do so if they are to attain a pure spiritual experience in its perfect integrity.
-- Notebooks Category 21: Mentalism > Chapter 5: The Key To the Spiritual World > # 194