In some cases, it is to one’s advantage to lie; only children and fools are unaware of this fact.
It can be traced back to a 14th century French proverb that translates to, To know the truth about everything, listen to drunkards, children, idiots, and women. The proverb was first used in English in the 16th century, in Letters & Papers of Reign of Henry VIII...an old saying that a child, a fool and a drunken man will ever show…the truth.