the bourgeoisie was revolutionary, natural sciences (geology and biology), too, were dominated by catastrophic theories, starting from the idea that the development of nature proceeds by sudden and enormous leaps and bounds. When, however, the middle class revolution was accomplished the place of the catastrophic theory was taken up by that of a gradual and inperceptible development, formed by the accumulation of countless and infinitesimal advances and adaptations in the struggle for existence. To the revolutionary middle-class the idea of catastrophies, even in Nature, was very congenial; to the conservative middle-class this idea appeared irrational and unnatural.
I, of course, do not mean to assert that the natural philosophers were each time prompted in choice of their theory by the political and social needs of the bourgeoisie. On the contrary, the upholders of catastrophic theories ware often enough extremely reactionary and least of all in sympathy with any revolutionary ideas. But every one is involuntarily influenced by the mode of thinking of the class in which he lives, and everyone carries a certain amount of it into his scientific views. In the case of Darwin we know for a fact that his scientific hypotheses were strongly influenced by the economic views of Malthus, a decided opponent of the revolution. Nor is it wholly accidental that the theories of evolution came from England (Lyell, Darwin), the country whose history for the last 250 years has only shown revolutionary beginnings which the governing classes always knew how to nip in the bud.
Of course, the dependence of a theory on the opinions prevailing in the class from which it arises, does not in the least prove its correctness or incorrectness. Still, its historical success much depends upon those opinions. If the new theories of development were at once and with enthusiasm accepted by the masses of the people who were absolutely unable to test them, that was due to the fact that they responded to deeply-felt needs of those people. On one hand—and this rendered them valuable in the eyes of the revolutionary section as well—they superseded much more thoroughly than the old catastrophic theories all and every necessity to postulate a supernatural power, which by a series of creative acts pushes the world ever farther and farther. On the other side, and in this they chiefly pleased the middle-class, they declared all revolution, all catastrophic change, as something unnatural, as something opposed to the laws of nature—therefore also irrational. Whoever wishes, now-a-days, to combat, scientifically, the revolution, does it in the name of the scientific theory of evolution, which shows that nature knows no leaps, that all sudden change in the social condition is impossible, that progress can only proceed by way of accumulation of the smallest changes and improvements called in society social reforms. The revolution regarded from this point of view is an unscientific conception at which scientifically-educated men can only shrug their shoulders.
