An investment in knowledge pays the best interest.

· Benjamin Franklin

The important thing is not to stop questioning.

· Albert Einstein

Learning never exhausts the mind.

· Leonardo da Vinci

It is impossible for a man to learn what he thinks he already knows.

· Epictetus

Any man can make a mistake, but only a fool persists in his error.

· Cicero

I learned very early the difference between knowing the name of something and knowing something.

· Richard Feynman