The vulgar and common esteem is seldom happy in hitting right; and I am much mistaken if, amongst the writings of my time, the worst are not those which have most gained the popular applause.

Every day I hear stupid people say things that are not stupid.

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

Now, since everything else is furnished with the exact amount of needle and thread required to maintain its being, it is in truth incredible that we alone should be brought into the world in a defective and indigent state, in a state such that we cannot maintain ourselves without external aid.

I enter into discussion and argument with great freedom and ease, inasmuch as opinion finds me in a bad soil to penetrate and take deep root in. No propositions astonish me, no belief offends me, whatever contrast it offers to my own. There is no fancy so frivolous and so extravagant that it does not seem to me quite suitable to the production of the human mind.

Whoever will be cured of ignorance, let him confess it.

In my youth I studied for ostentation; later, a little to gain wisdom; now, for recreation; never for gain.