The Psychology of Dreams-by Carl Gustav Jung

A dream is a psychic structure which at first sight appears to be in striking contrast with conscious thought, because judging by its form and substance, it apparently does not lie within the continuity of development of the conscious contents, it is not integral to it, but is a mere external and apparently accidental occurrence. Its mode of genesis is in itself sufficient to isolate a dream from the other contents of the conscious, for it is a survival of a peculiar psychic activity which takes place during sleep, and does not originate in the manifest and clearly logical and emotional continuity of the event experienced.