The perception of the fundamental contradiction in German idealism led necessarily back to materialism, but, nota bene , not to the simply metaphysical, exclusively mechanical materialism of the eighteenth century. In contrast to the *****ly revolutionary, ****** rejection of all previous history, modern materialism sees in the latter the process of evolution of humanity, it being its task to discover the laws of motion thereof. With the French of the eighteenth century, and with Hegel, the conception obtained of nature as a whole, moving in narrow circles, and forever immutable, with its eternal celestial bodies, as Newton, and unalterable organic species, as Linnaeus, taught. Modern materialism embraces the more recent discoveries of natural science, according to which nature also has its history in time, the celestial bodies, like the organic species that, under favourable conditions, people them, being born and perishing. And even if nature, as a whole, must still be said to move in recurrent cycles, these cycles assume infinitely larger dimensions. In both cases modern materialism is essentially dialectic, and no longer needs any philosophy standing above the other sciences. As soon as each special science is bound to make clear its position in the great totality of things and of our knowledge of things, a special science dealing with this totality is superfluous.
That which still survives, independently, of all earlier philosophy is the science of thought and its laws -- formal logic and dialectics. Everything else is subsumed in the positive science of nature and history.
Whilst, however, the revolution in the conception of nature could only be made in proportion to the corresponding positive materials furnished by research, already much earlier certain historical facts had occurred which led to a decisive change in the conception of history. In 1831, the first working-class rising took place in Lyons; between 1838 and 1842, the first national working-class movement, that of the English Chartists, reached its height. The class struggle between proletariat and bourgeoisie came to the front in the history of the most advanced countries in Europe, in proportion to the development, upon the one hand, of modern industry [ grosse Industrie ], upon the other, of the newly-acquired political supremacy of the bourgeoisie. Facts more and more strenuously gave the lie to the teachings of bourgeois economy as to the identity of the interests of capital and labour, as to the universal harmony and universal prosperity that would be the consequence of unbridled competition. All these things could no longer be ignored, any more than the French and English socialism, which was their theoretical, though very imperfect, expression. But the old idealist conception of history, which was not yet dislodged knew nothing of class struggles based upon economic interests, knew nothing of economic interests; production and all economic relations appeared in it only as incidental, subordinate elements in the "history of civilisation".
The new facts made imperative a new examination of all past history.
Then it was seen that all past history was the history of class struggles [27] ; that these warring classes of society are always the products of the modes of production and of exchange -- in a word, of the economic conditions of their time; that the economic structure of society always furnishes the real basis, starting from which we can alone work out the ultimate explanation of the whole superstructure of juridical and political institutions as well as of the religious, philosophical, and other ideas of a given historical period.
But now idealism was driven from its last refuge, the philosophy of history;now a materialistic treatment of history was propounded, and a method found of explaining man's "knowing" by his "being", instead of, as heretofore, his "being" by his "knowing".
But the socialism of earlier days was as incompatible with this materialistic conception as the conception of nature of the French materialists was with dialectics and modern natural science. The socialism of earlier days certainly criticised the existing capitalistic mode of production and its consequences. But it could not explain them, and, therefore, could not get the mastery of them. It could only simply reject them as bad. But for this it was necessary (1) to present the capitalistic method of production in its historical connection and its inevitableness during a particular historical period, and therefore, also, to present its inevitable downfall;and (2) to lay bare its essential character, which was still a secret, as its critics had hitherto attacked its evil consequences rather than the process of the thing itself. This was done by the discovery of surplus-value. It was shown that the appropriation of unpaid labour is the basis of the capitalist mode of production and of the exploitation of the worker that occurs under it, that even if the capitalist buys the labour-power of his labourer at its full value as a commodity on the market, he yet extracts more value from it than he paid for; and that in the ultimate analysis this surplus-value forms those sums of value from which are heaped up the constantly increasing masses of capital in the hands of the possessing classes. The genesis of capitalist production and the production of capital were both explained.
These two great discoveries, the materialistic conception of history and the revelation of the secret of capitalistic production through surplus-value, we owe to Marx. With these discoveries socialism became a science.
The next thing was to work out all its details and relations.