The Interpretation of Dreams by Sigmund Freud Chapter 9 Page 11

is contrasted with other more familiar psychic forces; the problem, however, disappears when we regard the dream as a form of expression for feelings which are burdened with resistance during the day and which can receive reinforcements at night from deep emotional sources. But the great respect shown by the ancients for the dream is based on a correct psychological surmise. It is a homage paid to the unsubdued and indestructible in the human mind, and to the demoniacal which furnishes the dream-wish and which we find again in our unconscious.

Not inadvisedly do I use the expression “in our unconscious,” for what we so designate does not coincide with the unconscious of the philosophers, nor with the unconscious of Lipps. In the latter uses it is intended to designate only the opposite of conscious.