Rosmini presents the two elements not well harmonized, as the eudæmonological and the ethical. Rights for him are not mere eudæmonism, but a eudæmonistic fact, produced by moral right and receiving form from it; hence the science of rights "stands between Eudæmonology and Ethic, so that one of its ends extends to the one and the other to the other." It would not be easy to explain and to justify what he calls a mediate science, composed of Eudæmonology and Ethic; and it would be far less easy to explain how this science comes to be "completely distinct" as regards its components. If rights have a moral form, they are moral and not eudæmonological. Owing to this difficulty Rosmini was led to introduce the concept of the licit as criterion of differentiation, defining right as "a personal faculty and power of enjoying, acting and being able to act, a lawful good that must not be impeded by others."[20] Juridically understood this constitutes a tautology, ethically something worse. Other Catholic authors (Taparelli, for example) deplore the separation of _ethos_ from _jus,_ introduced (they say) by Protestant doctrines and the limitation of right to what a man can externally exact from others according to law; "whence it happens that in the enumeration of laws, actions are sometimes posited that are real moral faults in the agent"; maintaining on the contrary the necessity of treating morality and rights together, "for rights are part of morality in the same way that trigonometry and conic sections are a part of geometric theories."[21] [Sidenote: _Stahl, Ahrens, Trendelenburg._]