contribution of the dream-work, and a mark of the assistance of dark powers in the depths of the psyche (cf. the devil in Tartini's sonata-dream). The intellectual achievement as such belongs to the same psychic forces as are responsible for all such achievements during the day. We are probably much too inclined to over-estimate the conscious character even of intellectual and artistic production. From the reports of certain writers who have been highly productive, such as Goethe and Helmholtz, we learn, rather, that the most essential and original part of their creations came to them in the form of inspirations, and offered itself to their awareness in an almost completed state. In other cases, where there is a concerted effort of all the psychic forces, there is nothing strange in the fact that conscious activity, too, lends its aid. But it is the much-abused privilege of conscious activity to hide from us all other activities wherever it participates.

It hardly seems worth while to take up the historical significance of dreams as a separate theme. Where, for instance, a leader has been impelled by a dream to engage in a bold undertaking, the success of which has had the effect of changing history, a new problem arises only so long as the dream is regarded as a mysterious power and contrasted with other more familiar psychic forces. The problem disappears as soon as we regard the dream as a form of expression for impulses to which a resistance was attached during the day, whilst at night they were able to draw reinforcement from deep-lying sources of excitation. * But the great respect with which the ancient peoples regarded dreams is based on a just piece of psychological divination. It is a homage paid to the unsubdued and indestructible element in the human soul, to the demonic power which furnishes the dream- wish, and which we have found again in our unconscious.

* Cf. (chapter II.), the dream (Sa-Turos) of Alexander the Great at the siege of Tyre.

It is not without purpose that I use the expression in our unconscious, for what we so call does not coincide with the unconscious of the philosophers, nor with the unconscious of Lipps. As they use the term, it merely means the opposite of the conscious. That there exist not only conscious but also unconscious psychic processes is the opinion at issue, which is so hotly contested and so energetically defended. Lipps enunciates the more comprehensive doctrine that everything psychic exists as unconscious, but that some of it may exist also as conscious. But it is not to prove this doctrine that we have adduced the phenomena of dreams and hysterical symptom-formation; the observation of normal life alone suffices to establish its correctness beyond a doubt. The novel fact that we have learned from the analysis of psycho-pathological formations, and indeed from the first member of the group, from dreams, is that the unconscious- and hence all that is psychic- occurs as a function of two separate systems, and that as such it occurs even in normal psychic life. There are consequently two kinds of unconscious, which have not as yet been distinguished by psychologists. Both are unconscious in the psychological sense; but in our sense the first, which we call Ucs, is likewise incapable of consciousness; whereas the second we call Pcs because its excitations, after the observance of certain rules, are capable of reaching consciousness; perhaps not before they have again undergone censorship, but nevertheless regardless of the Ucs system. The fact that in order to attain consciousness the excitations must pass through an unalterable series, a succession of instances, as is betrayed by the changes produced in them by the censorship, has enabled us to describe them by analogy in spatial terms. We described the relations of the two systems to each other and to consciousness by saying that the system Pcs is like a screen between the system Ucs and consciousness. The system Pcs not only bars access to consciousness, but also controls the access to voluntary motility, and has control of the emission of a mobile cathectic energy, a portion of which is familiar to us as attention. *

* Cf. here my remarks in the Proceedings of the Society for Psychical Research, vol. xxvi, in which the descriptive, dynamic and systematic meanings of the ambiguous word Unconscious are distinguished from one another.

We must also steer clear of the distinction between the super- conscious and the subconscious, which has found such favour in the more recent literature on the psychoneuroses, for just such a distinction seems to emphasize the equivalence of what is psychic and what is conscious.