There is a book I came across within the last year or so, entitled "The True and the False Infallibility of the Popes", by Bishop Joseph Fessler, 1875. He was the Secretary General of the Vatican Council (1870), and wrote this short work in defence of the dogma recently defined by Pope Pius IX. What spurred Bishop Fessler to write this was the errors about papal infallibility being spread by Bishop Schulte.
I have never heard of any traditional catholic clergy knowing of this book, or having read it. I have observed that sede's tend to exaggerate the Pope's infallibility, and some SSPX people do not understand or accept it as they should. Perhaps if all the traditional catholic clergy read and discussed it, they would at least become closer to being on the same page. Pun intended.
The Pope highly praised the author's work, as being an authentic interpretation of the dogma defining papal infallibility, and one may read it at the beginning of the book.
Online: https://archive.org/details/a628790300fessuoft/page/n1/mode/2up
Hard copy: https://www.amazon.com/gp/product/B0DYVR7RNJ/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B0DYVR7RNJ&linkCode=as2&tag=httpwwwchanco-20 />
Please share this book as much as you are able, it is important to read in its entirety, however these particular passages are quite intriguing, as it is relevant to the current crisis.
P. 74:
Dr. Schulte proceeds with another Bull of Pope Paul IV., issued in the year 1559 (cuм Ex Apostolatus) which is rightly described in the collection of Papal Bulls under the title of 'Renewal of previous censures and punishments against heretics and schismatics, with the addition of further penalties.' Why, the very title, which gives a true account of its contents, is of itself alone enough to show every one who reads it, that this Papal delivery is not a definition de fide and cannot, therefore, be an utterance ex cathedrâ.
P: 75-76:
And indeed it is 'very remarkable,' nay quite 'inconceivable,' that Dr. Schulte, who is a canonist, should have so utterly misunderstood the introduction to this Bull, and the sense of a passage further on in it, § 6. I am conscious I am giving utterance to a grave reproof, and I must entreat my reader's patience while I prove it. Dr. Schulte finds it ' very remarkable ;' he says that 'the election of a heretic as Pope is valueless from the first, and is here declared to be null and void. That is, he says, 'The Pope and Cardinals assume the possibility of an infallible Pope being found deviating from the faith !'
To set this supposed case in its proper light the following remarks may be useful. Pope Paul lV, no doubt, supposes the case possible (however improbable it might be) that a man who clings to an heretical doctrine might be chosen Pope, and also that after he has mounted the Papal throne, he might still hold heretical doctrine, or, even it may be, express it in his intercourse with others; not, however, that he would teach the whole Church this heretical doctrine in an utterance of his supreme teaching office (ex cathedrâ). From making such an utterance God Himself, through His special assistance, preserves the Pope and the Church. If, then, as has been suggested, a man were elected Pope who might uphold heretical doctrine (not supposing that he could declare such a doctrine to the whole Church formally as Catholic doctrine de fide, or prescribe it to be held as such), then we should have the case before us for which Pope Paul IV, in the above-named Bull, § 6, provides, by quashing the election of such a man to the Papacy, and declaring it 'null and void.'
This is one of the cases which theologians mean when they say the Pope (homo privatus) as a private individual, may err in a matter of faith; that is, when he is considered simply as a man, with merely his own human conception of a doctrine of the faith. As Pope, as supreme teacher of the Catholic Church, he cannot err, when, by virtue of the assistance of God, promised and vouchsafed to him, he solemnly defines a truth revealed by God, and prescribes it to be held by the Universal Church. It is clear that there are in the one person of the Pope two different active powers: first, the ordinary power of thinking and viewing things; and, secondly, the solemn defining power for the whole Church.
I might illustrate this point by the parallel case of a judge who has to decide upon a suit. In his own private life he may, perhaps, hold and express his opinion, and that on very various occasions, but in the suit nothing passes for law but his solemn judicial utterance, which, however, is by no means infallible. The example, however, will suffice to show that a man who is invested with an official position can be readily conceived as thinking and speaking as a man, on the one hand, and, on the other hand, as an official personage in his forensic utterances and acts.
After making this distinction, plain enough as I conceive it to be, the introductory words of this Bull will be quite intelligible; why, that is, the Pope expresses his conviction how perilous it would be if, even in his private life, a Pope were to admit an error in doctrine, and what sad confusion would arise if the said Pope, as a private individual, were to be guilty of heresy, and yet had to put into force penalties against heretics, he as Pope having no judge higher than himself.
Thoughts?