Plato, Republic

[609a] as for example for the eyes ophthalmia, for the entire body disease, for grain mildew, rotting for wood, rust for bronze and iron, and, as I say, for practically everything its congenital evil and disease¹?” “I do,” he said. “Then when one of these evils comes to anything does it not make the thing to which it attaches itself bad, and finally disintegrate and destroy it?” “Of course.” “Then the congenital evil of each thing and its own vice destroys it, or if that is not going to destroy it, nothing else [609b] remains that could; for obviously² the good will never destroy anything, nor yet again will that which is neutral and neither good nor evil³.” “How could it?” he said. “If, then, we discover⁴ anything that has an evil which vitiates it, yet is not able to dissolve and destroy it, shall we not thereupon know that of a thing so constituted there can be no destruction?” “That seems likely,” he said. “Well, then,” said I, “has not the soul something that makes it evil?” “Indeed it has,” he said, “all the things that we were just now enumerating, [609c] injustice and licentiousness and cowardice and ignorance.” “Does any one of these things dissolve and destroy it? And reflect, lest we be misled by supposing that when an unjust and foolish man is taken in his injustice he is then destroyed by the injustice, which is the vice of soul. But conceive it thus: Just as the vice of body which is disease wastes and destroys it so that it no longer is a body at all,⁵ in like manner in all the examples of which we spoke it is the specific evil which, [609d] by attaching itself to the thing and dwelling in it with power to corrupt, reduces it to nonentity. Is not that so?” “Yes.” “Come, then, and consider the soul in the same way.⁶ Do injustice and other wickedness dwelling in it, by their indwelling and attachment to it, corrupt and wither it till they bring it to death and separate it from the body?” “They certainly do not do that,” he said. “But surely,” said I, “it is unreasonable to suppose that the vice of something else destroys a thing while its own does not.” “Yes, unreasonable.” “For observe, Glaucon,” [609e] said I, “that we do not think it proper to say of the body either that it is destroyed by the badness of foods themselves, whether it be staleness or rottenness or whatever it is;⁷ but when the badness of the foods themselves engenders in the body the defect of body, then we shall say that it is destroyed owing to these foods, but by⁸ its own vice, which is disease.