The existence of the state is inseparable from the existence of slavery.

The education of all children, from the moment that they can get along without a mother's care, shall be in state institutions.

Experience praises the most happy the one who made the most people happy.

There is no royal road to science, and only those who do not dread the fatiguing climb of its steep paths have a chance of gaining its luminous summits. (Preface to the French edition).

The bourgeoisie cannot exist without constantly revolutionizing the instruments of production, and thereby the relations of production, and with them the whole relations of society.

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

...it happens that society is saved as often as the circle of its ruling class is narrowed, as often as a more exclusive interest asserts itself over the general. Every demand for the most simple bourgeois financial reform, for the most ordinary liberalism, for the most commonplace republicanism, for the flattest democracy is forthwith punished as an assault upon society and is branded as Socialism.