The unexamined life is not worth living.

· Socrates

Knowledge speaks, but wisdom listens.

· Jimi Hendrix

I think, therefore I am.

· Rene Descartes

Men are disturbed not by the things which happen, but by the opinions about the things.

· Epictetus

Ignorance more frequently begets confidence than does knowledge.

· Charles Darwin

To thine own self be true.

· William Shakespeare