The longer we dwell on our misfortunes, the greater is their power to harm us.

I know that I am intelligent, because I know that I know nothing.

I decided to sell my drawings. However, I didn't want people to buy my drawings because the professor of physics isn't supposed to be able to draw - isn't that wonderful - so I made up a false name.

It is a mania shared by philosophers of all ages to deny what exists and to explain what does not exist.

Many are they who have a taste and love for drawing, but no talent; and this will be discernible in boys who are not diligent and never finish their drawings with shading.