fundamental form, memory, synthesis; and synthesis presupposes individuality. The material world shows us no real individualities; these are first known from the psychological standpoint, from which inner centers of memory, action, and endurance are discovered. If now we conceive of the individual mental elements (sensations, thoughts, feelings, etc.) as capable of being transposed to other combinations, like chemical atoms, it would follow that they might have an existence apart from a definite individual consciousness—a supposition which our account of consciousness shows to be absurd. Sensations, thoughts, and feelings are mental activities which can not persist when the definite individual connection in which they occur has come to an end. . . . The theory to which we are here led is not a complete solution of the problem between mind and body. It is only an empirical formula, an indication of the manner in which the relation presents itself provisionally, when, following the hint of experience, we take heed of the close connection between the mental and the material, and the impossibility of a reduction of the one to the other, together with the difficulties attending the notion of a transition from the one to the other. Concerning the inner relation between mind and matter, we teach nothing; we suppose only that one being works in both. But what kind of being is this? Why has it a double form of manifestation; why does not one form suffice? These are questions that lie beyond the realm of our knowledge. Mind and matter appear to us as an irreducible quality, just as subject and object. We therefore postpone the consideration of the question, since it is evident that it lies in reality far deeper than has been usually supposed. But the empirical formula with which we conclude does not exclude a more comprehensive metaphysical hypothesis.