HKB
which deals with the development of the elementary organism from germ to maturity; geology, which investigates the gradual formation of the earth's crust, are all the products of our century.
But, first of all, there are three great discoveries which have caused our knowledge of the interdependence of the processes of nature to progress by leaps and bounds. In the first place, the discovery of the cell, as the unit, from the multiplication and differentiation of which, the whole of plant and animal substance develop so that not only the growth and development of all higher classes of all higher organisms is recognized as following a universal law, but the very path is shown in the capacity for differentiation in the cell, by which organisms are enabled to change their forms and make thereby a more individual development. Secondly, the metamorphosis of energy which has shown us that all the so-called real forces in inorganic nature, the mechanical forces and their complements, the so-called potential energies, heat, radiation (light, radiating heat), electricity, magnetism, chemical energy, are different forms of universal motion, which pass, under certain conditions, the one into the other, so that in place of those of the one which disappear, a certain number of the other appear, so that the whole movement of nature is reduced to this perpetual process of transformation from one into the other. Finally, the proof first developed logically by Darwin, that the organic products of nature about us, including man, are the result of a long process of evolution, from a few original single cells, and these again, by virtue of chemical processes, have proceeded from protoplasm or white of egg.
Thanks to these three great discoveries and the resultant powerful advance of science, we have now arrived at a point where we can show the connection between changes in nature, not only in specific cases, but also in the relation of the specific cases to the whole and so give a bird's eye view of the interrelation of nature in an approximately scientific form by means of the facts shown by empirical science itself. To furnish this complete picture was formerly the task of the so-called philosophy of nature. It could then only do this by substituting ideal and imaginary hypotheses for the unknown real interconnection, by filling out the missing facts with mind-pictures and by bridging the chasms by empty imaginings. It had many happy thoughts in these transports (of imagination), it anticipated many later discoveries, but it also caused the survival of considerable nonsense up to the present time which could not otherwise have been possible. At present, when the results of the investigation of nature need only be conceived of dialectically, that is in the sense of their mutual interconnection, to arrive at a system of nature sufficient for our time, when the dialectical character of this interconnection forces itself into the metaphysically trained minds of experimental scientists, against their will, today a philosophy of nature is finally disposed of, every attempt at its resurrection would not only be superfluous, it would even be a step backwards.
But what is true of nature, which is hereby recognized as an historical process, is true also of the history of society in all its branches, and of the totality of all sciences which occupy themselves with things human and divine. Here also the philosophy of jurisprudence, of history, of religion, etc., consisted in this, that in place of the true interconnection of events, one originating in the mind of the philosopher was substituted; that history, in its totality as in its parts, was comprehended as the gradual realization of ideas, but, of course, always of the pet idea of the philosopher himself.