Someone at work stated flatly that rule of thumb comes from an old law permitting a man to beat his wife with a stick no thicker than his thumb, and that everyone should stop using the phrase. It gets repeated a lot but I've never seen anyone name the law. Is there a documented origin, and does the first recorded use point anywhere near that story?
Worth naming why this particular story spreads. It's memorable, it's morally charged, and it lets the teller be the person who knows something dark about an ordinary phrase. That combination beats an accurate but boring explanation nearly every time, which is roughly how all folk etymology works.
The literal origin is much duller and much more likely: your thumb is a measuring tool you always have with you. The first joint is roughly an inch on many adults, brewers judged temperature by dipping a thumb, carpenters marked with one. Any phrase meaning approximate measurement is going to reach for the body part people actually approximate with.
Several languages have the same idea independently, which is usually a decent sign that a story doesn't need a court case to explain it.
One nuance so it doesn't get flattened the other way: the caricature of Buller was real and the underlying legal attitudes of the period were genuinely grim. What isn't supported is the phrase coming from any of it. Both things can be true and people tend to argue as though they can't.
@analogy_ada · 5mo ago · 3 replies
The dates kill it, which is the cleanest way to settle these.
The earliest use anyone has found of the phrase in print is 1685, in a Scottish sermon by James Durham, complaining about people who go by no rule but the rule of thumb. It's used there exactly the way we use it now, meaning a rough practical guide rather than a precise measure.
The beating story is usually pinned on Francis Buller, an English judge who in 1782 was widely mocked in caricature for supposedly saying a husband could beat his wife with a stick no thicker than his thumb. There's no surviving record of him ruling any such thing, and even if he had, the phrase was already about a century old.
So you have a phrase attested in 1685 and a story dated 1782 that the phrase is supposed to have come from. That's not how time works.
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@listener_lena · 5mo ago
The 1685 sermon is exactly the sort of thing I couldn't find on my own. Do you know where that citation is usually sourced from?
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@analogy_ada · 5mo ago
It's the OED's earliest citation for the phrase, and it's repeated in most of the serious treatments. If you have a library card, a lot of public library systems give you OED access from home and you can read the citation list yourself, which is more satisfying than taking my word for it.
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