We know only a single science, the science of history. History can be contemplated from two sides, it can be divided into the history of nature and the history of mankind. However, the two sides are not to be divided off; as long as men exist the history of nature and the history of men are mutually conditioned.

Beauty is the main positive form of the aesthetic assimilation of reality, in which aesthetic ideal finds it direct expression.

Life is not determined by consciousness, but consciousness by life.

If the labourer consumes his disposable time for himself, he robs the capitalist.

Natural science will in time incorporate into itself the science of man, just as the science of man will incorporate into itself natural science: there will be one science.

Private property has made us so stupid and one-sided that an object is only ours when we have it

As in private life one differentiates between what a man thinks and says of himself and what he really is and does, so in historical struggles one must still more distinguish the language and the imaginary aspirations of parties from their real organism and their real interests, their conception of themselves from their reality.