But a second and more alarming wave threatens us: Community of wives and children. "You must prove both the possibility and desirability of that." Men and women must be trained together and live together, but not in licentiousness. They must be mated with the utmost care for procreation, the best being paired at due seasons, nominally by lot, and for the occasion. The offspring of the selected will have a common nursery; the mothers will not know which were their own children. Parentage will be permissible only between twenty-five and fifty-five, and between twenty and forty. The children begotten in the same batch of espousals will be brothers and sisters. The absence of "mine" and "thine" will ensure unity, because it abolishes the primary cause of discord; common maintenance by the state removes all temptation either to meanness or cringing. Our guardians will be uncommonly happy. As to practicability: communism is suitable for war. The youngsters will be taken to watch any fighting; cowards will be degraded; valour will be honoured, and death on the field, with other supreme services to the state, will rank the hero among demigods. Against Greeks war must be conducted as against our own kith and kin. But as to the possibility of all this--this third threatening wave is the most terrific of all. _IV.--Of Philosophy in Rulers_ It will be possible then, and only then, when kings are philosophers or philosophers kings. "You will be mobbed and pelted for such a proposition." Still, it is the fact. The philosopher desires all knowledge. You know that justice, beauty, good, and so on, are single, though their presentation is multiplex and variable. Curiosity about the multiplex particulars is not desire of knowledge, which is of the one constant idea--of that which is, as ignorance is of that which is not. What neither is nor is not, that which fluctuates and changes, is the subject matter of opinion, a state between knowledge and ignorance. Beauty is beauty always and everywhere; the things that look beautiful may be ugly from another point of view. Experience of beautiful things, curiosity about them, must be distinguished from knowledge of beauty; the philosopher is not to be confounded with the connoisseur, not knowledge with opinion. The philosopher is he who has in his mind the perfect pattern of justice, beauty, truth; his is the knowledge of the eternal; he contemplates all time and all existence; no praises are too high for his character. "No doubt; still, if that is so, why do professed philosophers always show themselves either fools or knaves in ordinary affairs?" A ship's crew which does not understand that the art of navigation demands a knowledge of the stars, will stigmatise a properly qualified pilot as a star-gazing idiot, and will prevent him from navigating. The world assumes that the philosopher's abstractions are folly, and rejects his guidance. The philosopher is the best kind of