=Plato’s Theory of Ethics.= Plato’s Theory of Ideas is, after all, fundamentally only an outspoken ethical metaphysics, and his Ethics is his most fruitful accomplishment. Plato’s ethical teaching is therefore involved in all that we have said about him up to this point. An understanding of his ethics includes an understanding of the formation and growth of his dialectic, an insight into his physical theory, knowledge of the two tendencies which run through his teaching, and especially an understanding of his doctrine of Love. If some of the previous exposition is repeated, it will be only to bring out more fully his ethical teaching as a special science. We shall speak of three topics under this general subject of his ethics: (1) his development of his theory of the Good; (2) the four cardinal virtues; (3) his theory of political society. =1. Development of Plato’s Theory of the Good.= Plato betrays his ascetic tendency in his first drafting of the Ideas and, as we have said, the double-world theory is the cause of this. Only one of the two worlds is real and will appeal to the Wise Man. The soul belongs to the supersensible world, and the knowledge, of which virtue consists, takes man away from the sensible world. Since earthly life is full of evil, the soul should die to it and turn away as soon as possible to the divine presence. This ascetic aspect of morality is set forth in the _Phædo_ and the _Theætetus_. In the general development of his metaphysics in the second drafting of his Ideas, Plato’s ethical theory developed also. He not only went beyond the abstract statement of Socrates, but beyond his own original asceticism. When he brought his two worlds into teleological relationship, he was logically compelled to abandon his conception of ascetic morals. The physical world has now a relative reality, and by the same sign sense-life has a relative moral value. It was Plato’s firm conviction that moral conduct makes man truly blessed, in this and another world. He still held, too, that this blessedness, this complete perfection of the soul, this sharing in the divine world of the Ideas, is the Highest Good. Yet he now came to recognize other kinds of happiness as steps toward the ideal Good. There are varieties of Goods, as appeared in his doctrine of Love. Besides the intuition of knowledge and its pleasures, there are physical Goods and their pleasures. Intellectual pleasure may be unmixed with pain, but there are also sensuous pleasures unmixed with pain. Here is indeed Plato, the Greek, speaking; Plato, the Greek artist, impelled by the charm of the Greek world around him. Strongly as he combated the Cyrenaic hedonism, and closely as he was allied to Socrates, his Greek nature gave way before the manifestations of the Idea of the Good in the physical world. The pleasure in nature objects, in educational development, in the practical and plastic arts, in mathematical sciences, and in the