"My immediate consciousness, my absolute perception, cannot go beyond myself, — I have immediate knowledge only of myself, whatever I know further I know only by reasoning, in the same manner in which I have come to those conclusions concerning the original powers of Nature, which certainly do not lie within the circle of my perceptions. I, however, — that which I call myself, — am not the man-forming power of Nature, but only one of its manifestations ; and only of this manifestation am I conscious, not of that power, whose existence I have only discovered from the necessity of explaining my own."