The concept of the unconscious is for me an exclusively psychological concept, and not a philosophical concept of a metaphysical nature. In my view the unconscious is a psychological borderline concept, which covers all psychic contents or processes that are not conscious, i.e., not related to the ego in any perceptible way. My justification for speaking of the existence of unconscious processes at all is derived simply and solely from experience. ~Carl Jung; Definitions; CW 6, par. 837.