But in reality this does not help us at all. For now we are definitely brought face to face with the quite unanswerable question, How, from all this homogeneity and unity of the ultimate particles and forces, can we account for the beginnings of the diversity which is so marked a characteristic of this world? Whence came the causes of the syntheses to higher unities, the reasons for the combination into higher resultants of energy? But even apart from that, it is quite obvious that we have not yet reached the ultimate point. For can “attraction,” influence at a distance, _vis a fronte_, be considered as a fact which is in itself clear? Is it not rather the most puzzling fundamental riddle we can be called upon to explain? Assuredly. And therefore the attempt is made to penetrate still deeper to the ultimate point, the last possible reduction to simpler terms, by referring all actual “forces” and reducing all movement, and therewith all “action,” to terms of attraction and repulsion, which are free from anything mysterious, whose mode of working can be unambiguously and plainly set forth in the law of the parallelogram of forces. Law? Set forth? Therefore still only description? Certainly only description, not explanation in the least. Even assuming that it is true, instead of a mere Utopia, that all the secrets and riddles of nature can be traced back to matter moved by attraction and repulsion according to the simplest laws of these, they would still only be summed up into a great general riddle, which is only the more colossal because it is able to embrace all others within itself. For attraction and repulsion, the transference of motion, and the combination of motion according to the law of the parallelogram of forces—all this is merely description of processes whose inner causes we do not understand, which appear simple, and are so, but are nevertheless not self-evident or to be taken as a matter of course; they are not in themselves intelligible, but form an absolute “world-riddle.” From the very root of things there gazes at us the same Sphinx which we had apparently driven from the foreground.