Incredible Coincidences That Are Hard To Believe Have Actually Happened

To demonstrate how common unlikely-seeming events can be, mathematicians like to trot out what is called the birthday problem. The question is how many people need to be in a room before there’s a 50/50 chance that two of them will share the same birthday. The answer is 23. “Oh, those guys and their birthdays really get me mad,” says Bernard Beitman, a psychiatrist and visiting professor at the University of Virginia, and author of the forthcoming book Connecting With Coincidence.