It has pleased God that divine verities should not enter the heart through the understanding, but the understanding through the heart.

Knowledge has two extremes. The first is the pure natural ignorance in which all men find themselves at birth. The other extreme is that reached by great minds, who, having run through all that men can know, find they know nothing, and come back again to that same natural ignorance from which they set out; this is a learned ignorance which is conscious of itself.

I have made this letter longer than usual, only because I have not had the time to make it shorter.

Orthodoxy on one side of the Pyrenees may be heresy on the other.

Who confers reputation? who gives respect and veneration to persons, to books, to great men? Who but Opinion? How utterly insufficient are all the riches of the world without her approbation!

Those honor nature well, who teach that she can speak on everything...

Continuity in everything is unpleasant.