A very distinctive rôle belongs to the coincidence of conscious attention with unconscious. An explanation of this process will help us, perhaps, to explain many incomprehensible and improbable things. “Even the unconscious psychic activities,--going up and down, smoking, playing with the hands, etc., conversation,--compete with the conscious or with other unconscious activities for psychic energy. Hence, a suddenly-appearing important idea may lead us to stop walking, to remain without a rule of action, may make the smoker drop his smoking, etc.” The explanation is as follows: I possess, let us say, 100 units of psychic energy which I might use in attention. Now we find it difficult to attend for twenty seconds to one point, and more so to direct our thought-energy to one thing. Hence I apply only, let us say, 90 units to the object in question, and apply 10 units to the unconscious play of ideas, etc. Now, if the first object suddenly demands even more attention, it draws off the other ten units, and I must stop playing, for absolutely without attention, even unconscious attention, nothing can be done. This very frequent and well-known phenomenon, shows us, first of all, the unconscious activities in their agreement with the conscious, inasmuch as we behave in the same way when both are interrupted by the demand of another thing on our attention. If a row suddenly breaks out before my window I will interrupt an unconscious drumming with the fingers as well as a conscious reading, so that it would be impossible to draw any conclusion concerning the nature of these activities from the mere interruption or the manner of that interruption. This similarity is an additional ground for the fact that what is done unconsciously may be very complex. No absolute boundary may be drawn, and hence we can derive no proof of the incorrectness of an assertion from the performance itself, i.e., from _what_ has been done unconsciously. Only human nature, its habits, idiosyncrasies, and its contemporary environment can give us any norm. Section 49. (d) Subjective Conditions.