THE SUBCONSCIOUS: Page 30

inevitable phase in the process constituting our mental activity; every mental act begins as an unconscious one, and it may remain so or go on developing into consciousness, according to whether it meets resistance or not." We are all familiar with the overnight solving of a problem unresolved before sleeping. This is consistent with Freud's comments on nocturnal mental activity in his study of dream processes. He tells us that "unsolved problems, harassing cares, and overwhelming impressions continue the activity of our thoughts even during sleep, maintaining psychic processes in the system which we have termed the preconscious. "The thought-impulses continued into sleep may be divided into the following groups: 1. Those which have been left uncompletedbecause our mental powers have failed us, i.e.,unsolved problems. 2. Those which have been suppressed andturned back during the day. 3. Those which have been excited in ourUcs. (unconscious) during the day by the working of the Pcs. (preconscious). 4. Those which have not been completedduring the day owing to some accidental cause. 5. The indifferent impressions of the day,which have therefore been left unsettled." Freud goes on to point out that preconscious activity will not become conscious mental processes during sleep.