The rule of thumb

Mind you, we don’t make the rules. We just report them.

The origins of the phrase ‘rule of thumb’ have been variously ascribed, but the one cited by Bill Bryson in Mother Tongue seems to be the most common and the most contentious. According to Bryson, the term ‘rule of thumb’ derives from medieval English common law wherein it was allowable to beat your wife with anything as thick as your thumb. Shovel handle? We have a problem, my friend. Willow switch? Meh.