Salt water when it turns into vapour becomes sweet, and the vapour does not form salt water when it condenses again. This I know by experiment. The same thing is true in every case of the kind: wine and all fluids that evaporate and condense back into a liquid state become water. They all are water modified by a certain admixture, the nature of which determines their flavour.
We have no evidence as yet about mind or the power to think; it seems to be a widely different kind of soul, differing as what is eternal from what is perishable; it alone is capable of existence in isolation from all other psychic powers.
Thus it is thought that justice is equality; and so it is, but not for all persons, only for those that are equal. Inequality also is thought to be just; and so it is, but not for all, only for the unequal. We make bad mistakes if we neglect this for whom when we are deciding what is just. The reason is that we are making judgements about ourselves, and people are generally bad judges where their own interests are involved.
Therefore the good man ought to be a lover of self, since he will then both benefit himself by acting nobly and aid his fellows; but the bad man ought not to be a lover of self, since he will follow his base passions, and so injure both himself and his neighbors. With the bad man therefore, what he does is not in accord with what he ought to do, but the good man does what he ought, since intelligence always chooses for itself that which is best, and the good man obeys his intelligence.
Every man should be responsible to others, nor should any one be allowed to do just as he pleases; for where absolute freedom is allowed, there is nothing to restrain the evil which is inherent in every man.
Those who assert that the mathematical sciences say nothing of the beautiful or the good are in error. For these sciences say and prove a great deal about them; if they do not expressly mention them, but prove attributes which are their results or definitions, it is not true that they tell us nothing about them. The chief forms of beauty are order and symmetry and definiteness, which the mathematical sciences demonstrate in a special degree.
Special care should be taken of the health of the inhabitants, which will depend chiefly on the healthiness of the locality and of the quarter to which they are exposed, and secondly on the use of pure water; this latter point is by no means a secondary consideration. For the elements which we use the most and oftenest for the support of the body contribute most to health, and among those are water and air. Wherefore, in all wise states, if there is want of pure water, and the supply is not all equally good, the drinking water ought to be separated from that which is used for other purposes.
All men agree that a just distribution must be according to merit in some sense; they do not all specify the same sort of merit, but democrats identify it with freemen, supporters of oligarchy with wealth (or noble birth), and supporters of aristocracy with excellence.