Be sincere and true to your word, serious and careful in your actions; and you will get along even among barbarians, But if you are not sincere and untrustworthy in your speech, frivolous and careless in your actions, how will you get along even among your own neighbors? When stand, see these principles in front of you; in your carriage see them on the yoke. Then you may be sure to get along.
My interest in science was always essentially limited to the study of principles.... That I have published so little is due to this same circumstance, as the great need to grasp principles has caused me to spend most of my time on fruitless pursuits.
For we do not think that we know a thing until we are acquainted with its primary conditions or first principles, and have carried our analysis as far as its simplest elements.
In [the soul] one part naturally rules, and the other is subject, and the virtue of the ruler we maintain to be different from that of the subject; the one being the virtue of the rational, and the other of the irrational part. Now, it is obvious that the same principle applies generally, and therefore almost all things rule and are ruled according to nature.
To see others suffer does one good, to make others suffer even more: this is a hard saying but an ancient, mighty, human, all-too-human principle [....] Without cruelty there is no festival.
Friendship with the upright, with the truthful and with the well informed is beneficial. Friendship with those who flatter, with those who are meek and who compromise with principles, and with those who talk cleverly is harmful.