To discover the various use of things is the work of history. - Karl Marx

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.

Art is always and everywhere the secret confession, and at the same time the immortal movement of its time.

Feuerbach is the only one who has a serious, critical attitude to the Hegelian dialectic and who has made genuine discoveries in this field. He is in fact the true conqueror of the old philosophy. The extent of his achievement, and the unpretentious simplicity with which he, Feuerbach, gives it to the world, stand in striking contrast to the opposite attitude (of the others). Feuerbach's great achievement is: (1) The proof that philosophy is nothing else but religion rendered into thought and expounded by thought, i.e., another form and manner of existence of the estrangement of the essence of man; hence equally to be condemned;(2) The establishment of true materialism and of real science, by making the social relationship of "man to man" the basic principle of the theory; (3) His opposing of the negation of the negation, which claims to be the absolute positive, the self-supporting positive, positively based on itself.