Notwithstanding their attacks on the basic conception of rationalism, on synthetic a priori judgments, that is, material propositions that cannot be contradicted by any experience, the empiricist posits the forms of being as constant.

A revolutionary career does not lead to banquets and honorary titles, interesting research and professorial wages. It leads to misery, disgrace, ingratitude, prison and a voyage into the unknown, illuminated by only an almost superhuman belief.

Reason as an organ for perceiving the true nature of reality and determining the guiding principles of our lives has come to be regarded as obsolete.

The inversion of external compulsion into the compulsion of conscience ... produces the machine-like assiduity and pliable allegiance required by the new rationality.

With the abolition of otium and of the ego no aloof thinking is left. ... Without otium philosophical thought is impossible, cannot be conceived or understood.

The facts which our senses present to us are socially performed in two ways: through the historical character of the object perceived and through the historical character of the perceiving organ. Both are not simply natural; they are shaped by human activity, and yet the individual perceives himself as receptive and passive in the act of perception.

The disparagement of empirical evidence in favor of a metaphysical world of illusion has its origin in the conflicy between the emancipated individual of bourgeois society and his fate within that society.