The attainment of truth is then the function of both the intellectual parts of the soul. Therefore their respective virtues are those dispositions which will best qualify them to attain truth.
Whatever we learn to do, we learn by actually doing it; men come to be builders, for instance, by building, and harp players by playing the harp. In the same way, by doing just acts we come to be just; by doing self-controlled acts, we come to be self-controlled ; and by doing brave acts, we become brave.
But it is not at all certain that this superiority of the many over the sound few is possible in the case of every people and every large number. There are some whom it would be impossible: otherwise the theory would apply to wild animals- and yet some men are hardly any better than wild animals.
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.
Of old, the demagogue was also a general, and then democracies changed into tyrannies. Most of the ancient tyrants were originally demagogues. They are not so now, but they were then; and the reason is that they were generals and not orators, for oratory had not yet come into fashion.
The so-called Pythagoreans, who were the first to take up mathematics, not only advanced this subject, but saturated with it, they fancied that the principles of mathematics were the principles of all things.
Money was established for exchange, but interest causes it to be reproduced by itself. Therefore this way of earning money is greatly in conflict with the natural law.
Now that practical skills have developed enough to provide adequately for material needs, one of these sciences which are not devoted to utilitarian ends [mathematics] has been able to arise in Egypt, the priestly caste there having the leisure necessary for disinterested research.
The most perfect political community must be amongst those who are in the middle rank, and those states are best instituted wherein these are a larger and more respectable part, if possible, than both the other; or, if that cannot be, at least than either of them separate.