The author relates Freud's theory of the unconscious to that of Descartes and compares both to C. S. Peirce's doctrine of "contrite fallibilism," which held that no knowledge is direct and intuitive—that all knowledge is subject to error. The author believes that anyone confined to insisting on the doctrine of the unconscious is limited in his ability to inquire and thus is impaired in his responsibility for learning and teaching. The consequences for therapy are also pointed out.Abstract Teaser