More quotes by René Descartes

"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."
"Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something."
"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."
"To live without philosophizing is in truth the same as keeping the eyes closed without attempting to open them."
"Except our own thoughts, there is nothing absolutely in our power."