John von Neumann draws attention to what seemed to him a contrast. He
remarked that for simple mechanisms, it is often easier to describe how they
work than what they do, while for more complicated mechanisms, it is usually
the other way around.
Von Neumann was the subject of many dotty professor stories. Von Neumann
supposedly had the habit of simply writing answers to homework assignments on
the board (the method of solution being, of course, obvious) when he was asked
how to solve problems....
