A question: how do we understand the infallibility of the Church’s magisterium?
Does it mean that the Church is entirely protected from ever teaching error infallibly (i.e., through papal decree or universal magisterium)? Or does it simply mean that whatever the Church has taught infallibly is not in error?
In other words, it is the case that the Church will never ever contradict itself, or is simply the case that if the Church were to contradict itself, the contradiction would not be binding?
When and where, if at all, has the nature of this infallibility been defined?
I ask this because I’m trying to better understand the sedevacantist position, which strikes me as strange.