Rene Descartes

Meditations On First Philosophy

"Reason already persuades me that I ought no less carefully to withhold my assent from matters which are not entirely certain and indubitable than from those which appear to me manifestly to be false, if I am able to find in each one some reason to doubt."

Discourse On Method

"From my childhood I lived in a world of books, and since I was taught that by their help I could gain a clear and assured knowledge of everything useful in life, I was eager to learn from them. But as soon as I had finished the course of studies which usually admits one to the ranks of the learned, I changed my opinion completely. For I found myself saddled with so many doubts and errors that I seemed to have gained nothing in trying to educate myself unless it was to discover more and more fully how ignorant I was."

Discourse On Method

"It is useful to know something...of different nations, that we may be enabled to form a more correct judgment regarding our own, and be prevented from thinking that everything contrary to our customs is ridiculous and irrational, -- a conclusion usually come to by those whose experience has been limited to their own country."