Barbaric accuracy - whimpering humility.

The course of the seasons is a piece of clockwork, with a cuckoo to call when it is spring.

I have often noticed that when people come to understand a mathematical proposition in some other way than that of the ordinary demonstration, they promptly say, "Oh, I see. That's how it must be." This is a sign that they explain it to themselves from within their own system.

We have to believe that everything has a cause, as the spider spins its web in order to catch flies. But it does this before it knows there are such things as flies.

Nothing puts a greater obstacle in the way of the progress of knowledge than thinking that one knows what one does not yet know.

A man of spirit must not think of the word difficulty as so much as existing. Away with it!

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