"Common sense is not so common."

"The only true wisdom is in knowing you know nothing."

"He who has a why to live can bear almost any how."

"The measure of intelligence is the ability to change."

"Science is organized knowledge. Wisdom is organized life."

"It is not that I'm so smart. But I stay with the questions much longer."

"Knowing yourself is the beginning of all wisdom."

"Silence is a source of great strength."