The secret of change is to focus all of your energy, not on fighting the old, but on building the new.

The only true wisdom is in knowing you know nothing.

Be as you wish to seem.

Think good, and good follows. Think evil, and evil follows. You are what you think all day long.

The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.

I am not an Athenian or a Greek, but a citizen of the world.

An honest man is always a child.

If you can't explain it to a six year old, you don't understand it yourself.

I cannot teach anybody anything. I can only make them think.