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."

"I believe in working hard for what you want."

"Never underestimate the power of determination."

"I don't need a reason to fight."

"The most important thing is the mission. Nothing else matters."