lay bare its essential character, which was still a secret. This was done by the discovery of surplus-value. It was shown that the appropriation of unpaid labor 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 labor-power of his laborer 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.
