'Is there such a thing as a moral truth taught by nature itself and independent of ecclesiastical, political, and every other kind of social authority? Is there a moral law that is natural in the sense of being universally and incontestably valid—valid for men at all places and all times, indeed valid for any being that thinks and feels—and are we capable of knowing that there is such a law? ... My own answer is emphatically affirmative.' —Franz Brentano, The Origin of Our Knowledge of Right and Wrong Franz Brentano is one of the founding figures of twentieth century philosophy, celebrated for introducing the concept of intentionality as well as making significant contributions to ethics, philosophy of psychology and logic. He counted Sigmund Freud, Rudolf Steiner and Edmund Husserl amongst his students, and Freud wrote to his teacher to express his great admiration for him. The Origin of Our Knowledge of Right and Wrong is Brentano's most important book on ethics and moral