Didn't want to derail the thread on Bishop WIlliamson's Toronto conference by responding to this observation there, so started a new thread to discuss this precise distinction:
Looks like there are some persistent sedevacantists (during the Q&A session) trying to prod His Excellency into sedevacantism.
Commentary:
I noticed that myself.
Bishop Williamson correctly distinguishes between formal and material heretics.
Things get a bit hazy, however, when he asserts that formal heretics lose Church membership (which is certainly correct), but material heretics do not.
This is so because there is a further distinction between PUBLIC MATERIAL heresy, and COVERT MATERIAL heresy.
Covert material heretics certainly retain their membership in the Church.
However, it seems to be a disputed topic as to whether public material heretics retain Church membership, with the majority of theologians (at least the ones I have read on the issue) asserting they lose membership.
Therefore, to determine whether the popes are nopes (so far as the present cause/issue is concerned), it would seem to be necessary to determine two things:
1) Is it the opinion of the Church that public material heretics lose membership?
2) What exactly is the definition of a public material heretic?
All here know that I am not a sedevacantist.
Yet at the same time, in the interest of honesty, I think the distinction His Excellency offers against the sedevacantist conclusion does not go far enough until it takes into account and resolves the further issue/distinction on the fate and definition of the public material heretic.