This article intends to evaluate the philosophical importance of Freudian categories, such as negation and the hypotheses about the unconscious elaborated in 1946, tracing Freud’s argumentative horizon back to Kant’s considerations on the degree of perception of reality. A philosophical assessment is also suggested for the theories of I. Matte Blanco. Introducing himself as pupil and follower of Freud, he interprets the unconscious using symbolic logic and developments on mathematical set theories, resulting in the elaboration of the fundamental conceptual pair symmetric/asymmetric. Matte Blanco’s mathematical interpretations of the dynamics of the unconscious merge into a mystic background which only Freudian experimentalism can contain.
Keywords: Asymmetry, Mystic, Negation, Perceived Reality, Symmetry, Unconscious