"No criticism can be brought against a branch of technical science from outside; no thought fitted out with the knowledge of a period and setting its course by definite historical aims could have anything to say to the specialist. Such thought and the critical, dialectical element it communicates to the process of cognition, thereby maintaining conscious connection between that process and historical life, do not exist for empiricism; nor do the associated categories, such as the distinction between essence and appearance, identity in change, and rationality of ends, indeed, the concept of man, of personality, even of society and class taken in the sense that presupposes specific viewpoints and directions of interest."

“The quality of the human that precludes identifying the individual with the class is ‘metaphysical’ and has no place in empiricist epistemology. The pigeon hole into which a man is shoved circumscribes his fate.”

“If by enlightenment and intellectual progress we mean the freeing of man from superstitious belief in evil forces, in demons and fairies, in blind fate—in short, emancipation of fear—then denunciation of what is currently called reason is the greatest service reason can render.”

“When even the dictators of today appeal to reason, they mean that they possess the most tanks. They were rational enough to build them; others should be rational enough to yield to them.”

“At present, when the prevailing forms of society have become hindrances to the free expression of human powers, it is precisely the abstract branches of science, mathematics and theoretical physics, which … offer a less distorted form of knowledge than other branches of science which are interwoven with the pattern of daily life, and the practicality of which seemingly testifies to their realistic character.”

“When the great religious and philosophical conceptions were alive, thinking people did not extol humility and brotherly love, justice and humanity because it was realistic to maintain such principles and odd and dangerous to deviate from them, or because these maxims were more in harmony with their supposedly free tastes than others. They held to such ideas because they saw in them elements of truth, because they connected them with the idea of logos, whether in the form of God or of a transcendental mind, or even of nature as an eternal principle.”

“The concept of God was for a long time the place where the idea was kept alive that there are other norms besides those to which nature and society give expression in their operation.”