Last week's mention of the expression, "rule of thumb" barely hinted at the debate that has raged for years on whether the phrase has unsavoury origins.
To recap: The expression was coined several centuries ago to refer to the thumb's use as a handy unit of measurement. It evolved into a metaphor for a rough guideline: As a rule of thumb, don't dance with people wearing cleats. However, a number of people dislike the phrase because they believe it refers to an old rule that a husband could legally beat his wife if he used a stick no wider than his thumb.
As many readers wrote to point out, and as University of California English professor Henry Ansgar Kelly, University of Chicago student Sharon Fenick and author Christina Hoff Sommers separately wrote in the 1990s after much research (presumably using digital sources), the history is tangled.
For instance, some claim William Blackstone, the English judge whose 18th-century codification of past rules and customs underpins much of our common law, spoke of this rule. He did not. He wrote of past laws that had authorized husbands to beat their wives "in the same moderation that a man is allowed to correct his apprentices or children." He expressed his distaste for such laws. "With us, in the politer reign of Charles II, this power of correction began to be doubted, and a wife may now have security of peace against her husband; or, in return, a husband against his wife" -- although, he added, the practice was far from dead. No mention of thumbs.
The first mention of the thumb as a legitimate measure for a cudgel may have been in a 1782 judgment by Francis Buller, an English judge. The evidence is persuasive, if circumstantial. The famed English caricaturist James Gillray produced a scathing drawing of him as "Judge Thumb," alongside a husband who is beating his wife and telling her that it's legal because the stick is "not bigger than my thumb." Later authorities write that the story was widely believed at the time, but there appears to be no surviving record of such a ruling. (A ruling of thumb?) Three 19th-century U.S. courts referred to what they claimed was an old law that permitted a beating with a stick no broader than a thumb, but even here there is no mention of a "rule of thumb." That expression, Sommers wrote in her 1994 book Who Stole Feminism?, was used almost as an aside by Del Martin of the U.S. National Organization for Women, who referred to the U.S. judgments in a 1976 report: "For instance the common-law doctrine had been modified to allow the husband 'the right to whip his wife, provided that he used a switch no bigger than his thumb' -- a rule of thumb, so to speak."
The association of the beating with the "rule of thumb" was apparently then picked up by others. The poor expression deserves better; as I mentioned last week, it was well in use by 1692, when, as cited in The Oxford English Dictionary, Sir W. Hope wrote in Fencing-Master: "What he doth, he doth by rule of Thumb, and not by Art."
One bilingual note: Matthew Bartram wrote to point out that the French word for thumb and inch is the same: pouce. Or, to corrupt another old expression, pouce ça change, pouce c'est la même chose. Which, as puns go, probably puts me in line for the thumbscrew.