The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos

by Brian Greene

To think this through, consider first an analogous problem with simpler numbers. Imagine you work for the notorious film producer Harvey W. Einstein, who has asked you to put out a casting call for the lead in his new indie, Pulp Friction. “How tall do you want him?” you ask. “I dunno. Taller than a meter, less than two. But you better make sure whatever height I decide, there’s someone who fits the bill.” You’re tempted to correct your boss, noting that because of quantum uncertainty he really doesn’t need to have every height represented but, thinking back on what happened to the surly little talking fly who tried that, you refrain. Now you face a decision. How many actors should you have at the audition? You reason: If W. measures heights to a centimeter’s accuracy, there are a hundred different possibilities between one and two meters. So you need at least a hundred actors. But since some actors who show up may have the same height, leaving other heights unrepresented, you’d better gather more than a hundred. To be safe, maybe you should put out a call for a few hundred actors. That’s a lot, but fewer than what you’d need if W. measured heights to a millimeter’s accuracy. In that case, there’d be a thousand different heights between one and two meters, so to be safe you’d need to gather a few thousand actors.

Agh. This is just plain awful. A better analogy would be if W, in between assaulting various actresses, asked for someone 1000 feet tall. You could gather a million possibilities and you're chances are no better than if you stopped at ten.