One must judge men not by their opinions, but by what their opinions have made of them.

There are very many people who read simply to prevent themselves from thinking.

Some people read only because they are too lazy to think.

If there were only turnips and potatoes in the world, someone would complain that plants grow the wrong way.

The fly that doesn't want to be swatted is most secure when it lights on the fly-swatter.

The natural scientists of the previous age knew less than we do and believed they were very close to the goal: we have taken very great steps in its direction and now discover we are still very far away from it. With the most rational philosophers an increase in their knowledge is always attended by an increased conviction of their ignorance.

The thoughts written on the walls of madhouses by their inmates might be worth publicizing.