For it is owing to their wonder that men both now begin and at first began to philosophize... They were pursuing science in order to know, and not for any utilitarian end.
It is clear, then, that the earth must be at the centre and immovable, not only for the reasons already given, but also because heavy bodies forcibly thrown quite straight upward return to the point from which they started, even if they are thrown to an infinite distance. From these considerations then it is clear that the earth does not move and does not lie elsewhere than at the centre.
But the virtues we get by first exercising them, as also happens in the case of the arts as well. For the things we have to learn before we can do them, we learn by doing them, e.g. men become builders by building and lyre players by playing the lyre; so too we become just by doing just acts, temperate by doing temperate acts, brave by doing brave acts.
Now the goodness that we have to consider is clearly human goodness, since the good or happiness which we set out to seek was human good and human happiness. But human goodness means in our view excellence of soul, not excellence of body.
In poverty and other misfortunes of life, true friends are a sure refuge. The young they keep out of mischief; to the old they are a comfort and aid in their weakness, and those in the prime of life they incite to noble deeds.
What the statesman is most anxious to produce is a certain moral character in his fellow citizens, namely a disposition to virtue and the performance of virtuous actions.