Ethics has exhibited from the beginning a tendency to universalize its conceptions and take the central place in metaphysics. Thus with Plato good conduct was but a special case of goodness, the good being the most general principle of reality.[198:12] In modern times Fichte and his school have founded an ethical metaphysics upon the conception of duty.[198:13] In these cases ethics can be distinguished from metaphysics only by adding to the study of the good or of duty, a study of the special physical, psychological, and social conditions under which goodness and dutifulness may obtain in human life. It is possible to attach the name of ethics, and we have seen the same to be true of logic, either to a realm of ideal truth or to that realm wherein the ideal is realized in humanity. [Sidenote: The Virtues, Customs, and Institutions.] § 85. A systematic study of ethics requires that the _virtues_, or types of moral practice, shall be interpreted in the light of the central conception of good, or of conscience. _Justice_, _temperance_, _wisdom_, and _courage_ were praised by the Greeks. Christianity added _self-sacrifice_, _humility_, _purity_, and _benevolence_. These and other virtues have been defined, justified, and co-ordinated with the aid of a standard of moral value or a canon of duty. There is in modern ethics a pronounced tendency, parallel to those already noted in logic and æsthetics, to study such phenomena belonging to its field as have become historically established. A very considerable investigation of _custom_, _institutions_, and other social forces has led to a contact of ethics with anthropology and sociology scarcely less significant than that with metaphysics. * * * * * [Sidenote: The Problems of Religion. The Special Interests of Faith.] § 86. In that part of his philosophy in which he deals with faith, the great German philosopher Kant mentions God, Freedom, and Immortality as the three pre-eminent religious interests. Religion, as we have seen, sets up a social relationship between man and that massive drift of things which determines his destiny. Of the two terms of this relation, God signifies the latter, while freedom and immortality are prerogatives which religion bestows upon the former. Man, viewed from the stand-point of religion as an object of special interest to the universe, is said to have a soul; and by virtue of this soul he is said to be free and immortal, when thought of as having a life in certain senses independent of its immediate natural environment. The attempt to make this faith theoretically intelligible has led to the philosophical disciplines known as _theology_ and _psychology_.[199:14] [Sidenote: Theology Deals with the Nature and Proof of God.]