Humor is the only test of gravity, and gravity of humor; for a subject which will not bear raillery is suspicious, and a jest which will not bear serious examination is false wit.

Boundaries don't protect rivers, people do.

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.

It is no part of a physician's business to use either persuasion or compulsion upon the patients.

Men are divided between those who are as thrifty as if they would live forever, and those who are as extravagant as if they were going to die the next day.

... the friendship of worthless people has a bad effect (because they take part, unstable as they are, in worthless pursuits, and actually become bad through each other's influence). But the friendship of the good is good, and increases in goodness because of their association. They seem even to become better men by exercising their friendship and improving each other; for the traits that they admire in each other get transferred to themselves.

The worst form of inequality is to try to make unequal things equal.