Rene Descartes — "I think, therefore I am."

"I suppose therefore that all the things I see are false; I believe that none of those things ever existed which my fallacious memory represents to me; I consider that I possess no senses; I imagine th…"

"My purpose is not to teach a method which everyone ought to follow to guide his reason, but only to show how I have tried to guide mine."

"I have always taken the greatest pleasure in seeking out and acquiring knowledge."

"I was very surprised to find that I had been mistaken more often than not in my life."

"The first precept was never to accept anything for true which I did not clearly know to be such."