Brevity: To say at once whatever is to be said.

One of the greatest creations of the human mind is the art of reviewing books without having read them.

Honest unaffected distrust of human abilities under all circumstances is the surest sign of strength of mind.

Do not judge God's world from your own. Trim your own hedge as you wish and plant your flowers in the patterns you can understand, but do not judge the garden of nature from your little window box.

I ceased in the year 1764 to believe that one can convince one’s opponents with arguments printed in books. It is not to do that, therefore, that I have taken up my pen, but merely so as to annoy them, and to bestow strength and courage on those on our own side, and to make it known to the others that they have not convinced us.

The feeling of health can only be gained by sickness.

If we make a couple of discoveries here and there we need not believe things will go on like this for ever. Just as we hit water when we dig in the earth, so we discover the incomprehensible sooner or later.