chords of the soul, and then acts harmoniously in every relation of life. *444* And injustice, which is the insubordination and disobedience of the inferior elements in the soul, is the opposite of justice, and is inharmonious and unnatural, being to the soul what disease is to the body; for in the soul as well as in the body, good or bad actions produce good or bad habits. And virtue is the health and beauty and well-being of the soul, and vice is the disease and weakness and deformity of the soul. *445* Again the old question returns upon us: Is justice or injustice the more profitable? The question has become ridiculous. For injustice, like mortal disease, makes life not worth having. Come up with me to the hill which overhangs the city and look down upon the single form of virtue, and the infinite forms of vice, {lxvii} among which are four special ones, characteristic both of states and of individuals. And the state which corresponds to the single form of virtue is that which we have been describing, wherein reason rules under one of two names--monarchy and aristocracy. Thus there are five forms in all, both of states and of souls.... [Sidenote: _Republic IV._ Introduction.] In attempting to prove that the soul has three separate faculties, Plato takes occasion to discuss what makes difference of faculties. And the criterion which he proposes is difference in the working of the faculties. The same faculty cannot produce contradictory effects. But the path of early reasoners is beset by thorny entanglements, and he will not proceed a step without first clearing the ground. This leads him into a tiresome digression, which is intended to explain the nature of contradiction. First, the contradiction must be at the same time and in the same relation. Secondly, no extraneous word must be introduced into either of the terms in which the contradictory proposition is expressed: for example, thirst is of drink, not of warm drink. He implies, what he does not say, that if, by the advice of reason, or by the impulse of anger, a man is restrained from drinking, this proves that thirst, or desire under which thirst is included, is distinct from anger and reason. But suppose that we allow the term 'thirst' or 'desire' to be modified, and say an 'angry thirst,' or a 'revengeful desire,' then the two spheres of desire and anger overlap and become confused. This case therefore has to be excluded. And still there remains an exception to the rule in the use of the term 'good,' which is always implied in the object of desire. These are the discussions of an age before logic; and any one who is wearied by them should remember that they are necessary to the clearing up of ideas in the first development of the human faculties.