The blow-up problem

Von Neumann was consulted by a group who was building a rocket ship to send into outer space. When he saw the incomplete structure, he asked, “Where did you get the plans for this ship?” He was told, “We have our own staff of engineers.” He disdainfully replied: “Engineers! Why, I have completely sewn up the whole mathematical theory of rocketry. See my paper of 1952.”

Well, the group consulted the 1952 paper, completely scrapped their ten-million-dollar structure, and rebuilt the rocket exactly according to Von Neumann’s plans. The minute they launched it, the entire structure blew up.

They angrily called Von Neumann back and said: “We followed your instructions to the letter. Yet when we started it, it blew up! Why?”

Von Neumann replied, “Ah yes; that is technically known as the blow-up problem — I treated that in my paper of 1954.”

The joke above is one of my favorites, in terms of illuminating a common interaction among technical types. (See also Pray, Mister Babbage.) This particular retelling comes from Raymond Smullyan’s book What Is the Name of This Book? (1978).

We’ve all by now heard the joke about the tourist who asks how to get to (Dublin, or Aberdeen, or Millinocket, or wherever) and the laconic local who replies “If I were trying to get there, I wouldn’t start from here.” Well, Smullyan had his own version of that one.

My favorite Vermonter story is about the tourist traveling in Vermont who came across a fork in the road. On one road was a sign: “To White River Junction.” On the other road was a sign: “To White River Junction.” The tourist scratched his head in perplexity, spied a Vermont native standing at the intersection, went over to him and asked, “Does it make any difference which road I take?”

The Vermonter replied, “Not to me it doesn’t.”

Posted 2019-01-14