A theory resting upon the view that human beings act consciously and purposefully fulfills this requirement. That human beings act consciously and purposefully cannot be refuted, for anyone who tries to do so does it consciously and purposefully, thus contradicting himself. Murray N. Rothbard wrote, "But while most things have no consciousness and therefore pursue no goals, it is an essential attribute of man's nature that he has consciousness, and therefore that his actions are self-determined by the choices his mind makes."