THE OBJECTIFICATION OF THE WILL. 183
causes and effects may be the manifestation of the most different kinds of forces, whose successive visible appearances are conducted through it, as I have illustrated above by the example of a metal machine. But the difference of these original forces, which cannot be referred to each other, by no means breaks the unity of that chain of causes, and the connection between all its links. The etiology and the philosophy of nature never do violence to each other, but go hand in hand, regarding the same object from different points of view. Etiology gives an account of the causes which necessarily produce the particular phenomenon to be explained. It exhibits, as the foundation of all its explanations, the universal forces which are active in all these causes and effects. It accurately defines, enumerates, and distinguishes these forces, and then indicates all the different effects in which each force appears, regulated by the difference of the circumstances, always in accordance with its own peculiar character, which it discloses in obedience to an invariable rule, called a law of nature. When all this has been thoroughly accomplished by physics in every particular, it will be complete, and its work will be done. There will then remain no unknown force in unorganised nature, nor any effect, which has not been proved to be the manifestation of one of these forces under definite circumstances, in accordance with a law of nature. Yet a law of nature remains merely the observed rule according to which nature invariably proceeds whenever certain definite circumstances occur. Therefore a law of nature may be defined as a fact expressed generally — un fait généralisé — and thus a complete enumeration of all the laws of nature would only be a complete register of facts. The consideration of nature as a whole is thus completed in morphology, which enumerates, compares, and arranges all the enduring forms of organised nature. Of the causes of the appearance of the individual creature it has little to say, for in all cases this is procreation (the theory of
