=Conservation considered as an undifferentiated psychical something or “psyche.”=—It is difficult to state this hypothesis clearly and precisely for it is necessarily vague, transcending as it does human experience. It is conceived, as I understand the matter, or at least the hypothesis connotes, that ideas of the moment, after ceasing to be a part of awareness, subside and become merged in some form or other in a larger mind or consciousness of which they were momentary concrete manifestations or phases. This consciousness is conceived as a sort of unity. Ideas out of awareness still persist as consciousness in some form though not necessarily as specific ideas. According to this hypothesis, it is evident that when the ideas of the moment’s awareness subside and become merged into the larger consciousness either one of two things must happen; they must either be conserved as specific ideas, or lose their individuality as states of consciousness, and become fused in this larger consciousness as an undifferentiated psychical something. Some like to call it a “psyche,” apparently finding that by using a Greek term, or a more abstract expression, they avoid the difficulties of clear thinking. The first alternative is equivalent to the hypothesis of conservation in the form of coconscious specific ideas which we have just discussed. The second alternative still leaves unexplained the mechanism by which differentiation again takes place in this psychical unity, how a conscious unity becomes differentiated again into and makes up the various phases (ideas) of consciousness at each moment; that is, the mechanism of memory. But, aside from this difficulty, the hypothesis is opposed by evidence which we have already found for the persistence of ideas (after cessation as states of consciousness) in some concrete form capable of very specific activity and of producing very specific effects. We have seen that such ideas may under certain conditions continue to manifest the same specific functionating activity as if continuing their existence in concrete form (e. g., so-called subconscious solution of problems, physiological disturbances, etc.). This phenomenon is scarcely reconcilable with the hypothesis that ideas after passing out of awareness lose their concrete specificity and become merged into an undifferentiated psychical something.[55] Furthermore, for a concept transcending experience to be acceptable it must be shown that it adequately explains all the known facts, is incompatible with none, and that the facts are not intelligible on any other known principle. These conditions seem to me far from having been fulfilled. Before accepting such a concept it is desirable to see if conservation cannot be brought under some principle within the domain of experience.