Proofs and jokes have a lot in common.
One similarity is their structure. Just as the conclusion of a proof must be justified by the premises, the punch line of a joke must be supported by a series of statements. The following joke provides an example.
- During a flight from Warsaw to New York, members of the flight crew became ill. When the pilot and copilot passed out, flight attendants began asking if anyone on board could fly the plane.
- An elderly Polish gentleman said he had flown supply planes in the army many years ago.
- He was escorted to the cockpit, but upon looking at the controls, he realized that this plane was far more complicated than the ones he had flown years ago.
- He told the flight attendant that he would not be able to fly the plane.
- “I’m sorry,” he said. “I’m just a simple Pole in a complex plane.”
Notice that each statement 1-4 alludes to a different part of the punch line in statement 5. Without any of them, the joke fails. Similarly, a proof with an unsupported conclusion will be invalid. Continue reading