英語時差：觀測選擇

Observational selection, on this Moment of Science. D: Grubs, on today's moment of science. Grubs are really cool because if you squish 'em . . . oh, I give up. I can't read this.

Y: Why not?

D: I'm sorry, Ya?l, I'm just discouraged. You see, for years now I've been telling people fun little facts about everyday science.

Y: Yes?

D: And science is all about rationality. It's about figuring out the way things really work. But my belief has been shaken since I heard about Michael Drosnin's book The Bible Code.

Y: Oh, that's the bestseller where the author made strings of letters by taking, say, every 50th letter from a famous bible passage. Then he claimed those strings predicted the future.

D: That's the one! The new strings of letters keep producing words and even phrases! It can't be a coincidence.

Y: Can't it? Statisticians call this kind of thing "observational selection." That means if you are allowed to ignore all the data that add up to nothing, it's actually easy to come up with apparently amazing coincidences. An Australian computer scientist named Brendan McKay set out recently to demonstrate that the same thing can be done with any long book. He applied Drosnin's observational selection technique to Moby Dick and produced such eerie phrases as "M L King" next to "To be shot by them" and "Princess Di" next to "mortal in the jaws of death."D: Hmmm . . . so by throwing away all the strings that spell nothing, you can just wait until eventually a coincidence comes along. That's the error of observational selection.

Y: Right.

D: OK, I guess I can read about grubs.