In order to arouse sympathy, the aristocracy was obliged to lose sight, apparently, of its own interests, and to formulate its indictment against the bourgeoisie in the interest of the exploited working class alone. Thus, the aristocracy took their revenge by singing lampoons on their new masters and whispering in his ears sinister prophesies of coming catastrophe.

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 method of production of the material things of life generally determines the social, political and spiritual currents of life.

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

Religion is the impotence of the human mind to deal with occurrences it cannot understand.

The product of mental labor - science - always stands far below its value, because the labor-time necessary to reproduce it has no relation at all to the labor-time required for its original production.

Philosophy stands in the same relation to the study of the actual world as masturbation to sexual love.