Quote by Descartes, René

"I think, therefore I am."

"The greatest minds are capable of the greatest vices as well as of the greatest virtues."

"Doubt is the key to knowledge."

"If you would be a real seeker of truth, it is necessary that at least once in your life you doubt, as far as possible, all things."

"Success comes to those who never give up."

"Success is measured by happiness, not money."

"You make your own luck in this world."

"You have to be organized to be successful in anything."