III. The mixture of philosophical concepts with empirical concepts and with rules is a vice common to nearly all treatises of the Philosophy of the practical, beginning with the _Nicomachean Ethic,_ which, although in certain places loftily philosophical, should be placed in greater part rather at the head of the history of the works of the moralists and of writers on the practical, than of Ethic. The author himself recognized this practical character when he wrote, _πάς ὁ περὶ τῶν πρακτῶν λόγος τύπῳ καὶ οὐκ ἀκριβῶς ὀφείλει λέγεσθαι.[4]_ And in this appears the prejudice that practical philosophy should be occupied with the practical: ἐπεὶ οὖν ἡ παροῦσα πραγματεία οὐ θεωρίας ἕνεκά ἐστιν ὥσπερ αἱ ἅλλαι (οὐ γὰρ ἵνα εἰδῶμεν τί εστιν ἡ ἀρετὴ σκεπτόμεθα άλλ' ἵν' ἀγαθοὶ ηινώμεθα, ἐπεὶ ούδὲν ἃν ἧν ὄφελος αὐτῆς), κτλ.[5] Even the greatest thinkers of modern times are not exempt from that characteristic. Emmanuel Kant, while recognizing that the division and treatment of duties do not belong to the Critique of the Sciences (he should therefore have excluded them from philosophy, which is always _criticism),_ finally relegates them to what he calls the "system" (and is in truth the anti-systematic)[6] and writes the _Metaphysic of Customs,_ divided into the doctrines of law and of the virtues. Fichte, in his _System of Ethic,_ makes the applied follow the theoretical part. Hegel gives the doctrine of duties in the third part of his _Philosophy of Law,_ which is entitled Of Ethicity (_Sittlichkeit_.) The Ethic of Herbart is intrinsically descriptive, for the author himself professed to wish simply "to describe the ideal of virtue,"[7] and the five practical ideas that he takes as principles were at bottom nothing but classes of virtue refined into ideas. Treatises of to-day are overflowing with empirical elements, as can be seen from those in English by Ladd and Seth, and by those in German of Paulsen, Wundt, and Cathrein. Sometimes a more concrete historical element is coupled in those treatises with the empirical classification of practical examples and institutions: as, for instance, in Cathrein, a modernized Jesuit, who exposes at length the moral views, not only of civilized people, ancient and modern, but also of the savages of Oceania, of Asia, of Cochin China, of the Hottentots and Boschimans, of the Botocudis, and so on. Questions of casuistry also survive in these treatises, such as whether and on what occasions it is permissible to tell a lie; this question is notably represented in the history of ideas, from the Socrates of the _Memorabilia_ to Kant and Schopenhauer.[8] Kant added questions of casuistry to the various sections of the _Metaphysic of Customs,_ as scholia to the system and examples of the way in which the truth of particular questions should be sought.[9] [Sidenote: _Vain attempts at definitions of empirical concepts._]