Clarity on a much-misunderstood issue…

The Question of Authority:
“Who are YOU to say who is a Heretic?”

It happens all the time when discussing Sedevacantism or related topics, especially with people in the recognize-and-resist camp, like adherents of the Society of St. Pius X or the Fraternity of St. Peter: Whenever the other side is out of arguments, the objection will be made that the sedevacantist has no authority to say what he is saying — for example, to determine who is a heretic, or to say whether a particular theological conclusion is indeed correct — as though it required an act of authority to discern whether a man is a Catholic or a heretic, or as though Catholic teaching were only to be held in theory but never allowed to be applied in practice to a concrete situation.