Abstract
It is a dark night and passengers have boarded an airplane. They have settled down, secured their safety belts, and the plane takes off. The destination and the time of departure and arrival are known. After cruising for a while, a calm but commanding voice is heard from the intercom: “This is Capt. Smith. I hope you're having a fine trip. I have two items to mention. One may be upsetting, but the other is good news. First, the upsetting news: we are lost. As for the good news: we are getting there in record time.”