The heart is the perfection of the whole organism. Therefore the principles of the power of perception and the souls ability to nourish itself must lie in the heart.
In the perfect state the good man is absolutely the same as the good citizen; whereas in other states the good citizen is only good relatively to his own form of government.
The structural unity of the parts is such that, if any one of them is displaced or removed, the whole will be disjointed and disturbed. For a thing whose presence or absence makes no visible difference is not an organic part of the whole.
We ought to be able to persuade on opposite sides of a question; as also we ought in the case of arguing by syllogism: not that we should practice both, for it is not right to persuade to what is bad; but in order that the bearing of the case may not escape us, and that when another makes an unfair use of these reasonings, we may be able to solve them.
For the real difference between humans and other animals is that humans alone have perception of good and evil, just and unjust, etc. It is the sharing of a common view in these matters that makes a household and a state.
It is clear that those constitutions which aim at the common good are right, as being in accord with absolute justice; while those which aim only at the good of the rulers are wrong.
Nature does nothing in vain. Therefore, it is imperative for persons to act in accordance with their nature and develop their latent talents, in order to be content and complete.