The free development of each is the condition for the free development of all.

Just as Darwin discovered the law of evolution in organic nature, so Marx discovered the law of evolution in human history; he discovered the simple fact, hitherto concealed by an overgrowth of idealogy [sic], that mankind must first of all eat and drink, have shelter and clothing, before it can pursue politics, science, religion, art etc.

The proletarians, driven to despair, will seize the torch which Stephens has preached to them; the vengeance of the people will come down with a wrath of which the rage of 1795 gives no true idea. The war of the poor against the rich will be the bloodiest ever waged.

Labour is the source of all wealth, the political economists assert. And it really is the source -- next to nature, which supplies it with the material that it converts into wealth. But it is even infinitely more than this. It is the prime basic condition for all human existence, and this to such an extent that, in a sense, we have to say that labour created man himself.

Just as Marx used to say about the French Marxists of the late 'seventies: All I know is that I am not a Marxist.

It is no longer a question anywhere of inventing interconnections from out of our brains, but of discovering them in the facts.

Freedom is the recognition of necessity.