The sole cause of man's unhappiness is that he does not know how to stay quietly in his room.

Sneezing absorbs all the functions of the soul just as much as the [sexual] act, but we do not draw from it the same conclusions against the greatness of man, because it is involuntary; although we bring it about, we do so involuntarily. It is not for the sake of the thing in itself but for another end, and is therefore not a sign of man's weakness, or his subjection to this act.

There are two equally dangerous extremes-to shut reason out, and to let nothing else in.

Custom determines what is agreeable.

I feel engulfed in the infinite immensity of spaces whereof I know nothing, and which know nothing of me, I am terrified The eternal silence of these infinite spaces alarms me.

Nature has some perfections to show that she is the image of God, and some defects to show that she is only His image.

What use is it to us to hear it said of a man that he has thrown off the yoke that he does not believe there is a God to watch over his actions, that he reckons himself the sole master of his behavior, and that he does not intend to give an account of it to anyone but himself?