It is impossible, or not easy, to alter by argument what has long been absorbed by habit

Men pay most attention to what is their own: they care less for what is common; or, at any rate, they care for it only to the extent to which each is individually concerned.

Why is it that all those who have become eminent in philosophy, politics, poetry, or the arts are clearly of an atrabilious temperament and some of them to such an extent as to be affected by diseases caused by black bile?

To die, and thus avoid poverty or love, or anything painful, is not the part of a brave man, but rather of a coward; for it is cowardice to avoid trouble, and the suicide does not undergo death because it is honorable, but in order to avoid evil.

The first essential responsibility of the state is control of the market-place: there must be some official charged with the duty of seeing that honest dealing and good order prevail. For one of the well-nigh essential activities of all states is the buying and selling of goods to meet their mutual basic needs; this is the quickest way to self-sufficiency, which seems to be what moves men to combine under a single constitution.

Happiness is an activity of the soul in accordance with virtue

Our virtues are voluntary (and in fact we are in a sense ourselves partly the cause of our moral dispositions, and it is our having a certain character that makes us set up an end of a certain kind), it follows that our vices are voluntary also; they are voluntary in the same manner as our virtues.