Historically, A “Devil’s Advocate” Was Employed To Argue Against?
Answer: Canonization of Saints
In common speech, we say we’re “playing the devil’s advocate” when we argue against a position we may agree with, for the sake of arguing and to provide an alternative viewpoint. If everyone at a work meeting agrees with a particular plan of action, for example, someone may take on the role of playing the devil’s advocate by arguing why the plan won’t work (even if they happen to like the plan) just to ensure nothing is overlooked.
The term is more than just a curious colloquial expression, however, and has roots in an actual position. Historically, a “Devil’s Advocate” wasn’t just somebody disagreeing on a matter, but a religious lawyer appointed by the Vatican to serve an important role during the canonization of saints. The formal title was promotor fidei, or, “Promoter of the Faith”, but the position was popularly referred to as advocatus diaboli, or, “Devil’s Advocate”.
The lawyer fulfilling that role would look for inconsistencies in stories about the saint-to-be, examine their character, argue that miracles attributed to them were poorly documented, fraudulent, or otherwise square off against the claims of the prelate theologian, or, “The Promoter of the Cause” but known popularly as, you guessed it, advocatus Dei, or, “God’s Advocate”.
While the role of Devil’s Advocate featured prominently in the canonization process for centuries, the role was greatly reduced in the 1980s when Pope John Paul II changed the canonization process to favor faster canonization of saints (more saints were canonized under John Paul than any other pope). Now the role is very rarely used except in cases of controversial figures. One such recent example was the canonization proceedings of Mother Teresa when Christopher Hitchens, a British-American essayist and critic who wrote a scathing book on Mother Teresa in 1995, was called upon by the Catholic Church to argue against her canonization.