HKB
to a certain point, proved that species can change and furthermore there was established the possibility of a common ancestry for organisms which partake of the characteristics of different species.
Darwin now examined the question whether there were not in nature causes--which without the conscious intention of the breeder--might in the course of time, by means of heredity, produce changes in the living animal analogous to those produced by scientific breeding. These causes he found in the disproportion between the enormous number of germs made by nature and the small number of beings which actually come to maturity. But as the germ struggles for its own development there is of necessity a consequent struggle for existence, which not only shows itself directly in the wear and tear of the body, but also as a struggle for space and light, as in the case of plants. And it is evident that in this fight those individuals have the best prospect of coming to maturity and reproducing themselves which possess certain qualities, perhaps insignificant, but advantageous in their fight for existence. There is a tendency towards the inheritance of these individual properties, and if they occur in several individuals of the same species towards development in the direction once taken, by virtue of the accumulated heredity, while the individuals which are not possessed of these qualities succumb more easily and little by little disappear in the struggle for existence. Thus a species naturally changes by the survival of the fittest.
Against this theory of Darwin Herr Duehring urges that the origin of the idea of the struggle for existence is, as Darwin himself confessed, based on the views of the political economist and theorist, Malthus, on the population question, and he covers it with all the abuse appropriate to the clerical Malthusian views on keeping down the population. Now it happens that Darwin never said that the cause of the struggle for existence theory was to be sought from Malthus. He only said that his theories respecting the struggle for existence are the theories of Malthus applied to the entire vegetable and animal world. How great a blunder Darwin made when he so naively accepted the teachings of Malthus without examination may be seen from the fact that there is no need to employ the spectacles of Malthus in order to detect the struggle for existence in nature,--the contradiction between the innumerable mass of germs which nature produces in such prodigality and the slight number which can manage to reach maturity, a contradiction which resolves itself into an apparently grim fight for existence. And with regard to the law of wages the Malthusian doctrines are widely advertised and Ricardo based his contentions upon them,--so the struggle for existence in nature may find a standing even without the Malthusian interpretation. Besides the organisms of nature have their law of population, the establishment of which would decide the theories of the development of species. And who gave the decisive impetus in that direction? Nobody but Darwin.