More quotes by René Descartes

"I think; therefore I am."
"If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things."
"I suppose therefore that all things I see are illusions; I believe that nothing has ever existed of everything my lying memory tells me. I think I have no senses. I believe that body, shape, extension, motion, location are functions. What is there then that can be taken as true? Perhaps only this one thing, that nothing at all is certain."
"There is nothing more ancient than the truth."
"Except our own thoughts, there is nothing absolutely in our power."