He also talks about possible alternatives to hammers. Eventually there are a thousand anti-hammerists. One day, one of them discovers a way to take off his hammer. So he takes it off and he throws it away. Every one knows that you can't possibly live without a hammer.
Years go by.
The number of anti-hammerists has grown to ten thousand. And nine more of them have shed their hammers. There are now ten non-hammerists. It's much more difficult to take the hammer out of your mind, than it is to take it off your hand. Practically everyone thinks he's crazy.