I tried to do a search here regarding this topic and found it difficult to find exactly what I was looking for.
Wrt the pope issue, I remember reading that what matters is not whether the pope heretic is material or formal, but rather public or private. I also remember something along the lines that a Catholic can not be a material heretic. A Catholic can only be a formal heretic.
Also when St. Robert Bellarmine talks about "heretic pope" what kind of heretic is he talking about?
In this thread, could we elaborate on this including Church teaching, etc that backs it up?
A heretic Pope would be a formal heretic. A purported Pope does not have ignorance as an excuse.
Check this out:
http://sedevacantist.com/forums/viewtopic.php?f=2&t=1628&sid=6ae4653b13d13e084a443efb7202fc0cLet's say that someone born and raised in the NO gets "elected" next time, and publicly teaches heresy. It would be right for the laity to avoid him. Now a true Pope is not avoided by the laity but embraced and they must, at their eternal peril submit to him. If this new "pope" continued to maintain V2, the new sacraments, the new canon law, and the new Saints, very public acts "bound on the Church" if he is a valid Pope we could be certain that he was not a valid Pope regardless of whether his heresy is formal or material. This would be true even if no one warned him he was incorrect, say if the SSPX gave up and stopped communicating with Rome.
But they will warn him and he will become pertinacious.
Only a Catholic can be Pope. So would one born and raised N.O. who got elected be valid? Suppose he revoked V2 and all the unCatholic things "bound" on the "Church" since V2? And never taught heresy publicly even as a private theologian? Never engaged in heretical acts such as worshiping with false religions?
It does in essence come down to public/private not formal/material. We judge in the external. Formal/material is judged by God. Public/private pertains to the crime. Formal/material pertains to the culpability.
It is indeed true that a formal heretic is a Catholic that rejects the faith and that a material heretic is a non-Catholic. But despite what feeneyites and all that want the gray to be either black or white might claim, there are qualifications. Many lay Catholics can err in good faith and not be a heretic at all. A clergyman can slip and teach heresy by mistake and not be a heretic, so long as he admits the error when corrected or repeatedly teach it. These are all hypotheticals whereas the constant heresies of the V2 "Popes" are realities. The reality is that a public [nothing about formal or material here] heretic cannot legitimately hold ecclesiastical office.
The theologians, almost without exception when touching on this issue make no distinction between formal and material from what I have read, merely public and private. Why would they all leave out such an important distinction? It is public heresy that destroys the visibility of the Church, not whether one is guilty of it or not.
Does that help at all?
This is what I believe the Catholic Church has taught. It is not my teaching.