It is easier to perceive error than to find truth, for the former lies on the surface and is easily seen, while the latter lies in the depth, where few are willing to search for it.

The world is so great and rich, and life so full of variety, that you can never lack occasions for poems.

Should I not be proud, when for twenty years I have had to admit to myself that the great Newton and all the mathematicians and noble calculators along with him were involved in a decisive error with respect to the doctrine of color, and that I among millions was the only one who knew what was right in this great subject of nature?

It has been said that figures rule the world. Maybe. But I am sure that figures show us whether it is being ruled well or badly.

Begin by instructing yourself, then you will receive instruction from others.

The most difficult thing is what is thought to be the simplest; to really see the things which are before your eyes.

What have the Germans gained by their boasted freedom of the press, except the liberty of abusing each other as they like?