The only good is knowledge and the only evil is ignorance.

Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science.

Beware of false knowledge; it is more dangerous than ignorance.

You don't know what you don't know.

Knowledge cannot be taken away from anyone except by obsolescence.

There's no such thing in aging, but maturing and knowledge. It's beautiful, I call that beauty.