Stubborn and ardent clinging to one's opinion is the best proof of stupidity.

Whatever is preached to us, and whatever we learn, we should still remember that it is man that gives, and man that receives; it is a mortal hand that presents it to us, it is a mortal hand that accepts it.

I see several animals that live so entire and perfect a life, some without sight, others without hearing: who knows whether to us also one, two, or three, or many other senses, may not be wanting?

The world is but a perennial movement. All things in it are in constant motion-the earth, the rocks of the Caucasus, the pyramids of Egypt-both with the common motion and with their own.

No one but yourself knows whether you are cowardly and cruel, or loyal and devout; others do not see you; they surmise you by uncertain conjectures; they perceive not so much your nature as your art.

Perhaps it is not without reason that we attribute facility in belief and conviction to simplicity and ignorance; for it seems to me I once learned that belief was sort of an impression made on our mind, and that the softer it is the less resistant t.

There is perhaps no more obvious vanity than to write of it so vainly.