Technically the term Devil’s Advocate refers to a person who takes the opposing view in any discussion. This person would be employed during the annulment process and would be known as the Defender of the Bond.
An annulment consists of a person questioning the validity of the marriage in a Church court known as a tribunal. While the one contesting the validity of the marriage would be assigned an advocate of their own, there is also another person assigned to be the Devil’s Advocate or Defender of the Bond. The Defender of the Bond makes sure all precautionary and discretionary data has been researched and completed so that if an annulment is granted there are no mistakes.
In the time prior to the Second Vatican Council, the canonization process also involved a Devil’s Advocate. This type of advocate would give reasons why the person up for canonization should not be canonized a saint. If there was very little opposing material, then the candidate would proceed towards canonization. The Devil’s Advocate was also known as the Promoter of the Cause or prosecuting attorney. They were authorized to examine virtues and reported miracles of one whose cause for beatification had been opened.
Since the new Code of Canon Law of 1983, the role of Devil’s Advocate for canonization has been assimilated into a broader investigation in that the advocate for the saint assumes the responsibilities formerly assigned to the Devil’s Advocate. An advocate interviews people who knew the proposed saint, takes testimony, and compiles data on the person. Also, all the letters, books, and articles written by the candidate for sainthood are researched by the advocate.
Finally, the people claiming a miracle through the intercession of the saint candidate would have to be investigated . These miracles are not only looked upon by the advocate, but also by medical doctors, psychologists, and clergy. So, there aren’t really opposing sides any more, but truth remains the object of all the investigation.
When the pope declares a person to be a saint in a solemn canonization ceremony, he does so infallibly. Papal infallibility is that gift from the Holy Spirit that preserves the pope from error in matters of faith and morals. This is why the investigation process for a candidate for sainthood is such a lengthy and thorough one; there can be no room for doubts.
Though “Devil’s Advocate” is an archaic term, its function is still very important and used in official canonical processes.