He who uses trickery should at least make use of his judgment to learn that he can scarcely hide treacherous conduct for very long among clever men who are determined to find him out, although they may pretend to be deceived in order to disguise their knowledge of his deceitfulness.

Pettiness of mind, ignorance and presumption are the cause of stubbornness, because stubborn people only want to believe what they themselves can imagine, and they can imagine very few things.

There is as much wisdom in soliciting good counsel as in giving it. The most sensible people are not reluctant to consider the feelings of other people; and to know how to submit to the wise guidance of others is a kind of wisdom in itself.

It is such a great fault to talk too much that, in business and conversation, if what is good is also brief, it is doubly good, and one gains by brevity what one often loses by an excess of words.

Self-love is almost always the ruling principle of our friendships. It makes us avoid all our obligations in unprofitable situations, and even causes us to forget our hostility towards our enemies when they become powerful enough to help us achieve fame or fortune.

In knowledge of human affairs, we should never allow our minds to be enslaved by others by subjecting ourselves to their whims. We must maintain freedom of thought, and never accept anything of purely human authority into our heads. When we are presented with a diversity of opinions, we must choose, if we can; if we cannot, we must remain in doubt.

Social intercourse, even friendship among most people, is a merely a business arrangement that lasts only so long as there is need.