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.

Ignorance, the root and stem of all evil.

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

The most important knowledge is that which guides the way you lead your life.

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.

Strong minds discuss ideas, average minds discuss events, weak minds discuss people