The psychical is concerned with imaginations, visions, voices, thoughts, and feelings which originate beneath the surface of the ego's mind, whereas the spiritual is concerned with the higher self. The two are not the same but utterly different in quality and character. Aspirants often confuse them although the first is still within the realm of personal things whereas the second is within the impersonal. A still greater confusion concerns the mediumistic. This is the same as the psychical but influenced or possessed by what purports to be someone else's ego, often someone unknown and usually unseen, or even by what purports to be from the realm of the spiritual itself.
-- Notebooks Category 16: The Sensitives > Chapter 3: Philosophy, Mysticism, and The Occult > # 75