“So must thou be. Thou canst not Self escape. So erst the Sibyls, so the Prophets told. Nor Time nor any Power can mar the shape Impressed, that living must itself unfold.” The mere chemistry of the stars, the mathematical side of physical observations, and physiology proper interested him, the great historian of Nature very little, because they belonged to Systematic and were concerned with experiential learning of the become, the dead, and the rigid. This is what underlies his anti-Newton polemic—a case in which, it must be added, both sides were in the right, for the one had “knowledge” of the regulated nature-process in the dead colour[177] while the experiencing of the other, the artist, was intuitive-sensuous “feeling.” Here we have the two worlds in plain opposition; and now therefore the essentials of their opposition must be stated with all strictness. History carries the mark of the _singular-factual_, Nature that of the _continuously possible_. So long as I scrutinize the image of the world- around in order to see by what laws it _must_ actualize itself, irrespective of whether it does happen or merely might happen— irrespective, that is, of time—then I am working in a genuine science. For the necessity of a nature-law (and there are no other laws) it is utterly immaterial whether it becomes phenomenal infinitely often or never. _That is, it is independent of Destiny._ There are thousands of chemical combinations that never are and never will be produced, but they are demonstrably possible and therefore they _exist_—for the fixed System of Nature though not for the Physiognomy of the whirling universe. A system consists of truths, a history rests on facts. Facts follow one another, truths follow _from_ one another, and this is the difference between “when” and “how.” That there has been a flash of lightning is a fact and can be indicated, without a word, by the pointing of a finger. “When there is lightning there is thunder,” on the contrary, is something that must be communicated by a proposition or sentence. Experience-lived may be quite wordless, while systematic knowing can only be through words. “Only that which has no history is capable of being defined,” says Nietzsche somewhere. But History is present becoming that tends into the future and looks back on the past. Nature stands beyond all time, its mark is extension, and it is without directional quality. Hence, for the one, the necessity of the mathematical, and for the other the necessity of the tragic.