"Rule of thumb" is a rude reference to an old law permitting men to beat their wives with a stick no thicker than a thumb, right? Wrong! It's one of the myths of women's history. Well, except that it may still be rude to use a phrase that you know will upset people. It may also be rude to assume that people who use the phrase are being rude. (Isn't etiquette wonderful?)
According to many attempts to research this history, the phrase "rule of thumb" predates by a couple of centuries the first known reference that connects it to a supposed law or custom about wife-beating.
A reference to this connection is found in 1881, in a book by Harriet H. Robinson: Massachusetts in the Woman Suffrage Movement. She says there, "By the English common law, her husband was her lord and master. He had the custody of her person, and of her minor children. He could 'punish her with a stick no bigger than his thumb,' and she could not complain against him."
Most of her statement is undoubtedly true: married women had little recourse if a husband treated her or her children badly, including many acts of battery.
There was an 1868 case, State v. Rhodes, where a husband was found innocent because, the judge said, "the defendant had a right to whip his wife with a switch no larger than his thumb," and in another case in 1874, State v. Oliver, the judge cited the "old doctrine, that a husband had a right to whip his wife, provided he used a switch no longer than his thumb" but continued on that this was "not law in North Carolina. Indeed, the Courts have advanced from that barbarism… "
A 1782 cartoon by James Gillray depicted a judge, Francis Buller, supporting this idea-and earned the judge the nickname, Judge Rule.
"Rule of thumb" as a phrase predates all such known references, in any case. The "rule of thumb" was used for measurements in many different fields, from brewing to money-changing to art.
If you read Robinson's paragraph carefully, she only ascribes that "her husband was lord and master" to English common law. The rest can be read as examples. It sounds as though she's quoting something or somebody.
We do have evidence that the phrase was used earlier, without reference to the "old doctrine" about wife-beating. It was used in a 1692 book on fencing, implying just what many use the phrase for today, a general rule to go by. In 1721, this appeared in print as a Scottish proverb: No Rule so good as Rule of Thumb.
We don't know where the phrase came from before that. It's still speculated that it originated as a carpenter's or gardener's guideline for a rough measurement.
Yet… there can be no doubt that wife-beating was once common and, in most legal circles, acceptable if it didn't "go too far." The origin of "rule of thumb" may not be accurate, but the culture that it calls to mind was real. Debunking the myth of the origin of "rule of thumb" may be fun, but that doesn't make domestic violence, past, and present, mythical. Nor is it a myth that culture has tolerated such violence. Domestic violence was, and is, very real. That women had little recourse was very real. Debunking the myth of the origin of "rule of thumb" cannot be used to debunk the reality of domestic violence or the role that cultural acceptance plays in keeping domestic violence a reality in too many lives.
Do You Use the Phrase or Not?
In her debunking of the connection of wife-beating to the phrase "rule of thumb," writer Rosalie Maggio suggests that people avoid the phrase anyway. Whether it was originally intended to refer to wife-beating, it has become associated with wife-beating over more than a century and is undoubtedly likely to distract many a reader from your main point if you use the phrase. Certainly, if the phrase is used in the context of feminism, women's lives or domestic violence, it would be in poor taste to use it. If it's used in other fields-especially the context of art, or brewing, or money-changing where it was used long before the association with wife-beating was made? Perhaps there are better ways to work against violence than pursuing a false etymology.
In the words of another author (Jennifer Freyd at the University of Oregon), "We caution readers to use restraint in judging others harshly for either their use of the phrase 'rule of thumb' or for their pain in hearing the phrase used and believing it refers to domestic violence."
- Kelly, Henry Ansgar. "Rule of Thumb and the Folklaw of the Husband's Stick." Journal of Legal Education. September 1994.
- Maggio, Rosalie. Talking About People: A Guide to Fair and Accurate Language. 1997.
- Safire, William. "Misrule of Thumb." New York Times. January 25, 1998.