Quote by René Descartes

"I think, therefore I am."

"Divide each difficulty into as many parts as is feasible and necessary to resolve it."

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

"Doubt is the key to knowledge."

"Perseverance is the key to success."

"Don't give up on what you believe in."

"I've been through worse."

"You learn to live with the pain."