Card Trick Involving Chance

A good card magician knows many tricks that depend on luck—they don’t always work, or even often work. There are some effects—they can hardly be called tricks—that might work only once in a thousand times! Here is what you do: You start by telling the audience you are going to perform a trick, and without telling them what trick you are doing, you go for the one-in-a-thousand effect. It almost never works, of course, so you glide seamlessly into a second try—for an effect that works about one time in a hundred, perhaps—and when it too fails (as it almost always will), you slide gracefully into effect number 3, which works only about one time in ten, so you’d better be ready with effect number 4, which works half the time (let’s say). If all else fails (and by this time, usually one of the earlier safety nets will have kept you out of this worst case), you have a failsafe effect, which won’t impress the crowd very much but at least it’s a surefire trick. In the course of a whole performance, you will be very unlucky indeed if you always have to rely on your final safety net, and whenever you achieve one of the higher-flying effects, the audience will be stupefied. “Impossible! How on earth could you have known which was my card?” Aha! You didn’t know, but you had a cute way of taking a hopeful stab in the dark that paid off. By hiding all the “mistake” cases from view—the trials that didn’t pan out—you create a “miracle.”

The idea is to rely on probability, have several tricks where the odds get better and better until p=1.