"We don't see things as they are, we see them as we are."

"Knowing yourself is the beginning of all wisdom."

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

"The mind is everything. What you think you become."

"Common sense is not so common."

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

"To know what you know and what you do not know, that is true knowledge."

"Silence is a source of great strength."