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.

The more I see, the less I know for sure.

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

Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.

Where there is shouting, there is no true knowledge.

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

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