The title of Sartre's Critique de la raison dialectique evokes, quite intentionally, memories of Kant's critiques of reason. Let us compare the two undertakings. Kant circumscribed the knowledge claimed by the natural sciences of his time. He pointed out that science never grasps more than the appearance of things as conditioned by our cognitive processes; it cannot know the thing-in-itself. Sartre, for his part, circumscribes the knowledge claimed by orthodox Marxism. He agrees that Marxist economic theory understands the general course of contemporary historical developments, but not the dynamics of those developments. Both authors concede no more than a limited validity in deterministic ontology, in the one case to the exact sciences, in the other to Marxism. Nevertheless, both recognize fully the content of the knowledge they are criticizing, but explain it at the result or product respectively of deeper causes. A transcendental investigation is supposed to bring these causes to light. Kant's critique of scientific reason was directed at the interplay between the presumed thing in itself and the viewing, thinking self—the interplay that yeilds objectively-cognizable Nature. Sartre's critique of dialectical reason tries to show that the interaction between individual human activity and an always scarce supply of material things is the source of all social and cultural forms and events. In both works, then, the human subject is a determining factor in what appears to be objectively factual.