“Never open a book with weather”

“In the Rain”, Sascha Kohlmann (CC BY-SA 2.0)

Every profession, hobby, and field of study has its share of lore, that is, its own body of unsubstantiated knowledge distributed by word-of-mouth and emails, often winding up in textbooks and reference material. Most “common knowledge” is lore. Everybody knows that Macs can’t get viruses—but they can get malware, and they do. Everybody knows that the French eat better than Americans—but watch the Parisians line up at McDo’s for their Quarter Poun...