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.
Karl MarxThe 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.
Karl MarxIt has drowned the most heavenly ecstasies of religious fervour, of chivalrous enthusiasm, of Philistine sentimentalism, in the icy water of egotistical calculation. It has resolved personal worth into exchange value, and in place of numberless indefeasible chartered freedoms, it has set up that single, unconscionable freedom -- free trade. In one word, for exploitation, veiled by religious and political illusions, it has substituted naked, shameless, direct, brutal exploitation.
Karl Marx