Two scientists can hardly be named who have, in the second half of the 19th century, dominated the human mind to a greater degree than Darwin and Marx. Their teachings revolutionized the conception that the great masses had about the world. For decades their names have been on the tongues of everybody, and their teachings have become the central point of the mental struggles which accompany the social struggles of today. The cause of this lies primarily in the highly scientific contents of their teachings. The scientific importance of Marxism as well as of Darwinism consists in their following out the theory of evolution, the one upon the domain of the organic world, of things animate; the other, upon the domain of society. This theory of evolution, however, was in no way new, it had its advocates before Darwin and Marx; the philosopher, Hegel, made it even as the central point of his philosophy. It is, therefore, necessary to observe closely what were the achievements of Darwin and Marx in this domain. The theory that plants and animals have developed one from another is met with first in the nineteenth century. Formerly the question, “Whence come all these thousands and hundreds of thousands of different kinds of plants and animals that we know?” was answered. “At the time of creation God created them all, each after its kind.” This primitive theory was in conformity with the experiences had and with the oldest information that could be got. According to the information, all known plants and animals have always been the same. Scientifically, this experience was thus expressed, “All kinds are invariable because the parents transmit their characteristics to their children.”