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

Religious distress is at the same time the expression of the real distress and also the protest against real distress. Religion is the sigh of the oppressed creature, the heart of a heartless world, just as it is the spirit of the spiritless condition. It is the opium of the people.

Money plays the largest part in determining the course of history.

Force is the midwife of every old society pregnant with a new one.

...the French Revolution gave rise to ideas which led beyond the ideas of the entire old world order. The revolutionary movement which began in 1789... gave rise to the communist idea which Babeuf's friend Buonarroti re-introduced in France after the Revolution of 1830. This idea, consistently developed, is the idea of the new world order.

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.

There are no circumstances imaginable, not even victory, under which the proletariat should give up its possession of arms.