Diogenes — Greek Philosopher

Diogenes of Sinope was a Greek philosopher and one of the founders of Cynic philosophy. Also known as Diogenes the Cynic, he was born in Sinope, an Ionian colony on the Black Sea, in 412 or 404 BCE and died at Corinth in 323 BCE... (wikipedia)

When I look upon seamen, men of science and philosophers, man is the wisest of all beings; when I look upon priests and prophets nothing is as contemptible as man.
As a matter of self-preservation, a man needs good friends or ardent enemies, for the former instruct him and the latter take him to task.
The foundation of every state is the education of its youth.
We have two ears and one tongue so that we would listen more and talk less.
The sun, too, shines into cesspools and is not polluted.