"Luck is what happens when preparation meets opportunity."

"Do not spoil what you have by desiring what you have not."

"You have power over your mind – not outside events. Realize this, and you will find strength."

"He who knows, does not speak. He who speaks, does not know."

"The more you struggle to live, the less you live. Give up the notion that you must be sure of what you are doing."

"Judge a man by his questions rather than by his answers."

"The heart has its reasons which reason knows nothing of."

"I think, therefore I am."

"Freedom is what you do with what’s been done to you."

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

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

"Real knowledge is to know the extent of one’s ignorance."

"Knowing yourself is the beginning of all wisdom."

"The greatest wealth is to live content with little."

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