I expect that most of us have heard the age old phrase "Rule of Thumb", and interpret it's meaning based upon the use of the phrase. For instance, one might say that Jane, as a rule of thumb, goes to the grocery store once a month. But, do you know where this old saying originated?

I just recently read that it originated from a very old English law. The law stated that it was permissible for a man to beat his wife with a stick, as long as the stick was no bigger than his thumb. 

If that were true, it simply shows that just because something is legal, it does not make it morally correct.