Dr. Carl Jung

By consciousness I understand the relation of psychic contents to the ego, in so far as this relation is perceived as such by the ego. Relations to the go that are not perceived as such are unconscious. Consciousness is the function or activity which maintains the relation of psychic contents to the ego. Consciousness is not identical with the psyche because the psyche represents the totality of all psychic contents, and these are not necessarily all directly connected with the ego, i.e., related to it in such a way that they take on the quality of consciousness.”

– C.G. Jung, Psychological Types, CW 6, par. 700