Let us call a halt to the vexatious and contradictory babble with which Herr Duehring proclaims his wrath against the advance given to science by the theory of Darwin. Neither Darwin nor his followers among the natural scientists have any idea of belittling Lamark's tremendous services, in fact they are the very people who first restored his fame. But we are unable to ignore the fact that in the time of Lamark science was still far from supplied with competent material to enable it to answer the question of the origin of species other than in a prophetic or, as it were anticipatory, manner. In addition to the enormous amount of material in the realm of general, as well as of that of anatomical, botany and zoology, accumulated since that time, two entirely new sciences have since come into existence--the investigation of the development of plant and animal germs (embryology), and the investigation of the organic survivals in the earth's crust which still remain. There is a distinct similarity between the steps in the development of the organic germ to mature organism, and the successive steps by which plants and animals succeed each other in the history of the world. It is just this similarity which has placed the evolution theory on its most secure foundations. The theory of evolution is however still very young and it is beyond question that upon further investigation the rigid Darwinian ideas upon the origin of species will be considerably modified. But what has the realist philosophy of a positive nature to contribute with respect to the evolution of organic life? "The variation of species is an acceptable supposition, but there exists, in addition, the independent order of the products of nature belonging to the same species without any intervention of descent." According to this we are to conclude that products of unlike species, that is species which vary, are descended from one another, but those of similar species not. But even this is not altogether correct, for he ventures to say of the varying species, "The part played by descent is on the contrary a very secondary activity of nature." There is heredity, then, but it is only to be reckoned as a factor of the second class. Let us be glad that heredity of which Herr Duehring has said so much that is evil and mysterious is at least let in by the back door. It is just the same with natural selection, since after all his moral indignation with respect to the struggle for existence by means of which natural selection fulfils itself he suddenly exclaims, "The most important constituent is to be found in the conditions of life and cosmic conditions, while natural selection as set forth by Darwin may be considered as secondary." Natural selection still exists, even if a factor of the second class, like the struggle for existence, and the clerical malthusian surplus-population theory. That is all, for the rest Herr Duehring refers us to Lamark.