Psychoanalysis is defined as a method and as an ontology of mental life. Its controversies are discussed both in terms of those within the discipline and in terms of the attacks on its scientificity by the proponents of “normal science” (analytico—referential or logical—empiricist). It is argued that the discoveries achieved by the free-associative method call into question the metaphysical assumptions on which all “normal science” is constructed. By showing that human consciousness is composed contradictorily of two dimensionalities of meaningfulness (semiosis and desire), psychoanalytic method challenges the axioms of a centered or unified rational subject that can aspire to formulate univocal “truths” about the self and its world. Our discipline thereby insists on a new notion of truth and of the knowing subject's relation to its own being. It is suggested that psychoanalysis is thus a “revolutionary science,” in ways that have yet to be fully comprehended, and its method implies a critique of the underlying precepts of all mainstream psychology.