I am outdoors on a sunny day at a large public gathering, where the atmosphere is something between a carnival and a revival meeting. A young man stands before a crowd and tries to sell himself as a psychic and predictor of future events with unusual powers. The crowd quietly listens to him, but I can tolerate it no longer. I walk to the front to challenge him. "Is there any proof of his powers?", I ask. "Yes", the young man answers, and he waves about a copy of a hard-cover book written by himself with a photograph of himself on the cover. I find this most unsatisfying and I deliver the real challenge: would he be willing to write down SPECIFIC predictions for the next ten years? "We can write them down tomorrow and check again after ten years.", I propose.