“All mysteries which lead theory to mysticism find their rational solution in human practice and in the comprehension of this practice.”

“Once the inner connection is grasped, all theoretical belief in the permanent necessity of existing conditions collapses before their collapse in practice-- Letter to Ludwig Kugelmann (July 11, 1868)”

“Both for the production on a mass scale of this communist consciousness, and for the success of the cause itself, the alteration of men on a mass scale is necessary, an alteration which can only take place in a practical movement, a revolution; this revolution is necessary, therefore, not only because the ruling class cannot be overthrown in any other way, but also because the class overthrowing it can only in a revolution succeed in ridding itself of all the muck of ages and become fitted to found society anew.”

“Language is as old as consciousness, language is practical, real consciousness that exists for other men as well, and only therefore does it also exist for me; language, like consciousness, only arises from the need, the necessity, of intercourse with other men.”

“In its rational form [dialectic] is a scandal and abomination to bourgeoisdom and its doctrinaire professors, because it includes in its comprehension and affirmative recognition of the existing state of things, at the same time also, the recognition of the negation of that state, of its inevitable breaking up; because it regards every historically developed social form as in fluid movement, and therefore takes into account its transient nature not less than its momentary existence because it lets nothing impose upon it, and is in its essence critical and revolutionary.”

“Communism is the riddle of history solved, and it knows itself to be this solution.”

“If money is the bond binding me to human life, binding society to me, connecting me with nature and man, is not money the bond of all bonds? Can it not dissolve and bind all ties? Is it not, therefore, also the universal agent of separation?”