2. VIRTUE.—In his theory of virtue, Plato is wholly Socratic. He holds fast to the opinion that it is science (_Protagoras_), and therefore, teachable (_Meno_), and as to its unity, it follows from the dialectical principle that the one can be manifold, or the manifold one, that, therefore, virtue must both be regarded as one, and also in a different respect, as many. Plato thus brings out prominently the union and connection of all virtues, and is fond of painting, especially in the introductory dialogues, some single virtue as comprising in itself the sum of all the rest. Plato follows for the most part the fourfold division of virtues, as popularly made; and first, in the Republic (IV. 441), he attempts a scientific derivation of them, by referring to each of the three parts of the soul its appropriate virtue. The virtue of the reason he calls prudence or wisdom, the directing or measuring virtue, without whose activity valor would sink to brute impulse, and calm endurance to stupid indifference; the virtue of spirit is valor, the help-meet of reason, or spirit (θυμὸς) penetrated by science, which in the struggle against pleasure and pain, desire and fear, preserves the rational intelligence against the alarms with which sensuous desires, would seek to sway the soul; the virtue of the sensuous desires, and which has to reduce these within true and proper grounds, is temperance, and that virtue in fine to which belong the due regulation and mutual adjustment of the several powers of the soul, and which, therefore, constitutes the bond and the unity of the three other virtues, is justice. In this last conception, that of justice, all the elements of moral culture meet together and centre, exhibiting the moral life of the individual as a perfect whole, and then, by requiring an application of the same principle to communities, the moral consideration is advanced beyond the narrow circle of individual life. Thus is established the whole of the moral world—Justice “in great letters,” the moral life in its complete totality, is the state. In this is first actualized the demand for the complete harmony of the human life. In and through the state comes the complete formation of matter for the reason.