[1] In common parlance, the phrase "playing devil's advocate" describes a situation where someone, given a certain point of view, takes a position they do not necessarily agree with (or simply an alternative position from the accepted norm), for the sake of debate or to explore the thought further using valid reasoning that both disagrees with the subject at hand and proves their own point valid.
During the investigation of a cause, this task is now performed by the 'Promoter of Justice' (promotor iustitiae), who is in charge of examining the accuracy of the inquiry on the saintliness of the candidate.
In cases of controversy, the Vatican may still seek to solicit the testimony of critics of a candidate for canonization.
One notable example of this was in 2003, when author Christopher Hitchens, an atheist and outspoken critic of Mother Teresa, was interviewed as part of her beatification hearings.
She also writes that inauthentic dissent can cause people to become more entrenched in their original beliefs, the opposite of the intended purpose e.g. in businesses that use this technique.