If you would be a real seeker after truth, it is necessary t... - René Descartes

"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."

"I hope that posterity will judge me kindly, not only as to the things which I have explained, but also to those which I have intentionally omitted so as to leave to others the pleasure of discovery."

"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."

"There is nothing more ancient than the truth."