Rule of Thumb

 I heard this myth again the other day. This myth refuses to die. In the past, a man had a right to beat his wife provided he did not use a stick thicker than his thumb.

There has never been a rule or a law in England that a man is entitled to beat his wife provided he uses a stick no thicker than his thumb. William Blackstone (1723-80) wrote Commentaries on the Laws of England (1765-1769). He made no mention of a supposed rule that a stick could be used to hit your wife if it was not thicker than a thumb. So it was never a part of English common law.

We are not certain how the phrase ‘rule of thumb’ arose but it probably came from craftsmen using their thumbs to measure.