Ever wondered how the phrase ‘Rule of the thumb’ came about?

Perhaps many of you have heard of the claim that the phrase was derived from an old English law which stated that a man could not beat his wife with anything wider than his thumb. I, for one, have heard that story often enough.

Well, for those who had believed it to be the truth, it’s time I debunked this urban myth.

A quick check is all it takes to dismiss this interesting but false theory. I came across a wonderful site that helps get our facts right. Let’s see what this site has to say:

“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.

The author pointed out that,

“That the phrase did not even originate in legal practice could have been ascertained by any fact-checker who took the trouble to look it up in the Oxford English Dictionary, which notes that the term has been used metaphorically for at least three hundred years to refer to any method of measurement or technique of estimation derived from experience rather than science.

In fact,

“British law since the 1700s and our American laws predating the Revolution prohibit wife beating, though there have been periods and places in which the prohibition was only indifferently enforced.”

Apparently, there never was a law that states that a man can beat his wife whether or not the instrument used was bigger or smaller than his thumb. It was then suggested that perhaps this myth was brought about because of this particular quote:

“In America, early settlers held European attitudes towards women. Our law, based upon the old English common-law doctrines, explicitly permitted wife-beating for correctional purposes. However, certain restrictions did exist and the general trend in the young states was toward declaring wife-beating illegal. 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”

—Del Martin, Battered Wives Volcano Press, 1976, page 31.

If anyone’s interested to know more, they can visit this wiki site.