The Sherlock Game

For those of you who watch the Sherlock BBC serial, here's a rationalist's game: try to extrapolate other hypotheses to explain the found evidence than those the protagonist came up with, and compare them in terms or relative likeliness. To give you an example of how it's done, from Pratchett;

[Vimes] distrusted the kind of person who'd take one look at another man and say in a lordly voice to his companion, "Ah, my dear sir, I can tell you nothing except that he is a left-handed stonemason who has spent some years in the merchant navy and has recently fell on hard times," and then unroll a lot of supercilious commentary about calluses and stance and the state of a man's boots, when exactly the same comments could apply to a man who was wearing his old clothes because he'd been doing a spot of home bricklaying for a new barbecue pit, and had been tattooed once when he was drunk and seventeen and in fact got seasick on a wet pavement. What arrogance! What an insult to the rich and chaotic variety of the human experience!