While most of those who hold that the whole heaven is finite say that the earth lies at the center, the philosophers of Italy, the so-called Pythagoreans, assert the contrary. They say that in the middle there is fire, and that the earth is one of the stars, and by its circular motion round the center produces night and day.
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.
For both excessive and insufficient exercise destroy one's strength, and both eating and drinking too much or too little destroy health, whereas the right quantity produces, increases and preserves it. So it is the same with temperance, courage and the other virtues. This much then, is clear: in all our conduct it is the mean that is to be commended.
Neither by nature, then, nor contrary to nature do the virtues arise in us; rather we are adapted by nature to receive them, and are made perfect by habit.
Now what is just and right is to be interpreted in the sense of 'what is equal'; and that which is right in the sense of being equal is to be considered with reference to the advantage of the state, and the common good of the citizens. And a citizen is one who shares in governing and being governed. He differs under different forms of government, but in the best state he is one who is able and willing to be governed and to govern with a view to the life of virtue.
Hence poetry is something more philosophic and of graver import than history, since its statements are of the nature rather of universals, whereas those of history are singulars.
Since we think we understand when we know the explanation, and there are four types of explanation (one, what it is to be a thing; one, that if certain things hold it is necessary that this does; another, what initiated the change; and fourth, the aim), all these are proved through the middle term.