This completely materialist conception of history is one of the greatest discoveries of our century, so rich in scientific discoveries. Thanks to it alone sociology has at last, and for ever, escaped from the vicious circle in which it had, until then, turned; thanks to it alone this science now possesses a foundation as solid as natural science. The revolution made by Marx in social science may be compared with that made by Kopernicus in astronomy. In fact, before Kopernicus, it was believed that the earth remained stationary, while the sun turned round it. The Polish genius demonstrated that what occurred was the exact contrary. And so, up to the time of Marx, the point of view taken by social science, was that of "human nature;" and it was from this point of view that men attempted to explain the historical movement of humanity. To this the point of view of the German genius is diametrically opposed. While man, in order to maintain his existence, acts upon nature outside himself, he alters his own nature. The action of man upon the nature outside himself, presupposes certain instruments, certain means of production; according to the character of their means of production men enter into certain relations within the process of production (since this process is a social one), and according to their relations in this social process of production, their habits, their sentiments, their desires, their methods of thought and of action, in a word, their nature, vary. Thus it is not human nature which explains the historical movement; it is the historical movement which fashions diversely human nature.
But if this is so, what is the value of all the more or less laborious, more or less ingenious enquiries into "perfect legislation" and the best of possible social organisations? None; literally none! They can but bear witness to the lack of scientific education in those who pursue them. Their day is gone for ever. With this old point of view of human nature must disappear the Utopias of every shade and colour. The great revolutionary party of our day, the International Social-
