Infinite liars

Regrettably, this chapter consists entirely of lies—every sentence in it, including this one, is false.

When my daughter Hypatia was very young, she liked to greet visitors to our home at the door with a friendly challenge:

Answer yes or no: will you answer no?

The guest would return her cheerful smile, yet stand flustered in the doorway with ponderous uncertainty. They were stymied by her question, for if they should answer yes, they would be saying that …