The second special limitation of this materialism lies in its incapacity to represent the universe as a process, as one form of matter assumed in the course of evolutionary development. This limitation corresponded with the natural science of the time and the metaphysic coincident therewith, that is the anti-dialectic methods of the philosophers. Nature, as was known, was in constant motion, but this motion, according to the universally accepted ideas, turned eternally in a circle, and therefore never moved from the spot, and produced the same results over and over again. This idea was at that time inevitable. The Kantian theory of the origin of the solar system was at first exhibited and considered as a mere curiosity. The history of the development of the earth-geology was still unknown, and the idea that the living natural objects of to-day are the result of a long process of development from the simple to the complex could not be scientifically established at that time. This anti-historical comprehension of nature was, therefore, inevitable. We cannot reproach the philosophers of the eighteenth century with this, as the same thing is also found in Hegel. According to him, nature is the mere outward form of the Idea, capable of no progress as regards time, but merely of an extension of its manifoldness in space, so that it displays all the stages of development comprised in it at one and the same time together, and is condemned to a repetition of the same processes. And this absurdity of a progress in space but outside of time--the fundamental condition of all progress--Hegel loads upon nature, just at the very time when geology, embryology, the physiology of plants and animals, and inorganic chemistry, were being built up, and when above all genial prophecies of the later evolution theory appeared at the very threshold of these new sciences (e. g., Goethe and Lamark), but the system so required it, and the method, for love of the system, had to prove untrue to itself. This unhistoric conception had its effects also in the domain of history. Here the fight against the remnants of the Middle Ages kept the outlook limited. The Middle Ages were reckoned as a mere interruption of history by a thousand years of barbarism. The great advances of the Middle Ages--the broadening of European learning, the bringing into existence of great nations, which arose, one after the other, and finally the enormous technical advances of the fourteenth and fifteenth centuries--all this no one saw. Consequently a rational view of the great historic development was rendered impossible, and history served principally as a collection of examples and illustrations for the use of philosophers.