In the two possible world-forms then—History and Nature, the physiognomy of all becoming and the system of all things become—destiny _or_ causality prevails. Between them there is all the difference between a feeling of life and a method of knowledge. Each of them is the starting- point of a complete and self-contained, but not _of a unique_ world. Yet, after all, just as the become is founded upon a becoming, so the _knowledge_ of cause and effect is founded upon the sure _feeling_ of a destiny. Causality is—so to say—destiny become, destiny made inorganic and modelled in reason-forms. Destiny itself (passed over in silence by Kant and every other builder of rational world-systems because with their armoury of _abstractions_ they could not touch _life_) stands beyond and outside all comprehended Nature. Nevertheless, being itself the original, it alone gives the stiff dead principle of cause-and- effect the opportunity to figure in the later scenes of a culture-drama, alive and historical, as the incarnation of a tyrannical thinking. The existence of the Classical soul is the _condition_ for the appearance of Democritus’s method, the existence of the Faustian soul for that of Newton’s. We may well imagine that either of these Cultures might have failed to produce a natural science of its own, but we cannot imagine the systems without their cultural foundations. Here again we see how becoming and the become, direction and extension, include one another and are subordinated each to the other, according as we are in the historical or in the “natural” focus. If history is that kind of world-order in which all the become is fitted to the becoming, then the products of scientific work must _inter alia_ be so handled; and, in fact, for the historical eye there is only a _history_ of physics. It was Destiny that the discoveries of oxygen, Neptune, gravitation and spectrum analysis happened as and when they did. It was Destiny that the phlogiston theory, the undulatory theory of light, the kinetic theory of gases could arise at all, seeing that they were elucidations of results and, as such, highly personal to their respective authors, and that other theories (“correct” or “erroneous”) might equally well have been developed instead. And it is again Destiny and the result of strong personality when one theory vanishes and another becomes the lodestar of the physicist’s world. Even the born physicist speaks of the “fate” of a problem or the “history” of a discovery.