I confine myself to the most promising instance, that of the amœba multiplying themselves by fission. This fact, interpreted according to science, would mean that here energy divides itself, exists alongside itself, since Weismann says that at the moment of partition neither of the two cells, if “endowed with self-consciousness,” could say which was mother and which daughter. “I have no doubt that each half would look upon the other as the daughter, and itself as the original individual,” he says in his _Dauer des Lebens_. Were there any real necessity to compel such an interpretation, then the single determination of energies would be riddled through and through. But there is no compelling necessity, nay, nor even possibility, of interpreting what happens after such a fashion. One is equally entitled to say that in the sundered sections a new energy lays hold. That this daughter-section continues its movements without a break is no proof of the orthodox conception of what takes place. The human sperm-cell, after its expulsion from the old organism, also for a longer time retains its own particular movements. It works itself towards the ovum against the vibratory movements of the epithelium; thus, so to speak, against the stream. Incidentally it may be remarked that this fact alone, interpreted according to physiology, would give rise to a difficulty that must render insoluble the entire problem of fecundation. For this movement of the sperm-cell renders necessary the question, “When precisely does the actual moment of fecundation occur? Is it at the first signs of conception? or at the moment when the sperm-cell penetrates the sheath of the ovum? or at the moment of their first mutual contact? or has not fecundation already virtually set in with this endeavour of the sperm-cell to get to the ovum-cell?” One might then inquire, after the fashion of jurists: “At what moment precisely is the deed born? Is it when I carry it out? or when I get ready to carry it out? or when I form the resolve to carry it out?” Such are the difficulties that arise when one seizes the problem of procreation in a purely materialistic way. And one is bound to seize it in a purely materialistic way if one would seize it scientifically. A single fact which contradicts the unique determination of a living being is not to be found, and never can be found. For this, it would be necessary that energy itself should be accessible, seizable by sense; and that is a contradiction in itself. One energy only is accessible--my consciousness. And this is _the_ uniquely determined.