A man cannot become a child again, or he becomes childish.

Surplus-value and the rate of surplus-value are... the invisible essence to be investigated, whereas the rate of profit and hence the form of surplus-value as profit are visible surface phenomena

A people without a heritage are easily persuaded.

The fact that labour is external to the worker, i.e., it does not belong to his intrinsic nature; that in his work, therefore he does not affirm himself but denies himself, does not feel content but unhappy, does not develop freely his physical and mental energy but mortifies his body and his mind. The worker therefore only feels himself outside his work, and in his work feels outside himself.

There is only one effective antidote for mental suffering and that is physical pain.

The task is not just to understand the world but to change it.

The entire so-called history of the world is nothing but the creation of man through human labor.