"rule of thumb" revisited

[Cohen, Gerald Leonard]

     A while back there was an ads-l discussion about the possible rationale for "rule of thumb." I just noticed a website which discusses this issue, including the incorrect interpretation that a man with a cheating wife was permitted to beat her if the rod used for this punishment was no thicker than a thumb. See http://www.debunker.com/texts/ruleofthumb.html

     Meanwhile, here's an excerpt from that website:
        "According to Canadian folklorist Philip Hiscock, "The real explanation of 'rule of thumb' is that it derives from wood workers... who knew their trade so well they rarely or never fell back on the use of such things as rulers. Instead, they would measure things by, for example, the length of their thumbs." Hiscock adds that the phrase came into metaphorical use by the late seventeenth century. Hiscock could not track the source of the idea that the term derives from a principle governing wife beating, but he believes it is an example of 'modern folklore' and compares it to other 'back-formed explanations.' such as the claim asparagus comes from 'sparrow-grass'...."

Gerald Cohen

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