Mankind suffers from two excesses: to exclude reason, and to live by nothing but reason.

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

The last advance of reason is to recognize that it is surpassed by innumerable things; it is feeble if it cannot realize that.

All the unhappiness of men arises from one single fact, that they cannot stay quietly in their own chamber.

What matters it that man should have a little more knowledge of the universe? If he has it, he gets little higher. Is he not always infinitely removed from the end, and is not the duration of our life equally removed from eternity, even if it lasts ten years longer?

I maintain that, if everyone knew what others said about him, there would not be four friends in the world.

Once your soul has been enlarged by a truth, it can never return to its original size.