Somehow or other, democratic stirrings happened in the protoplasm, and the struggle for existence of the rain-worms is a useful lesson for the bipeds who have scraped through. With all this, the historians have failed to learn the lesson that our ripest and strictest science, Physics, would have taught them, the lesson of prudence. Even if we concede them their causal method, the superficiality with which they apply it is an outrage. There is neither the intellectual discipline nor the keen sight, let alone the scepticism that is inherent in our handling of physical hypotheses.[175] For the attitude of the physicist to his atoms, electrons, currents, and fields of force, to æther and mass, is very far removed from the naïve faith of the layman and the Monist in these things. They are _images_ which he subjects to the abstract relationships of his differential equations, in which he clothes trans-phenomenal numbers, and if he allows himself a certain freedom to choose amongst several theories, it is because he does not try to find in them any actuality but that of the “conventional sign.”[176] He knows, too, that over and above an experimental acquaintance with the technical structure of the world-around, all that it is possible to achieve by this process (which is the only one open to natural science) is a symbolic interpretation of it, no more—certainly not “Knowledge” in the sanguine popular sense. For, the image of Nature being a creation and copy of the Intellect, its “alter ego” in the domain of the extended, to _know_ Nature means to know oneself. If Physics is the maturest of our sciences, Biology, whose business is to explore the picture of organic life, is in point both of content and of methods the weakest. What historical investigation _really_ is, namely pure Physiognomic, cannot be better illustrated than by the course of Goethe’s nature-studies. He works upon mineralogy, and at once his views fit themselves together into a conspectus of an earth-history in which his beloved granite signifies nearly the same as that which I call the proto-human signifies in man’s history. He investigates well- known plants, and the prime phenomenon of metamorphosis, the original form of the history of all plant existence, reveals itself; proceeding further, he reaches those extraordinarily deep ideas of vertical and spiral tendencies in vegetation which have not been fully grasped even yet. His studies of ossature, based entirely on the contemplation of life, lead him to the discovery of the “os intermaxillare” in man and to the view that the skull-structure of the vertebrates developed out of six vertebræ. Never is there a word of causality. He feels the necessity of Destiny just as he himself expressed it in his _Orphische Urworte_: