Saturday, July 18, 2020, marked the 150th anniversary of the definition of papal infallibility by the first Vatican Council in the constitution Pastor Aeternus, as a dogma of the Catholic faith, to be held by all Catholics under pain of losing their eternal salvation. On the same occasion, the same Vatican council, under the headship of Pope Pius IX, also defined as a dogma the universal jurisdiction of the pope over all the baptized — that is, the fact that the pope is by divine law the vicar of Christ and pastor of all Christians.
As the assembled fathers cast their votes in favor of the definition of infallibility, a great thunderstorm raged over St. Peter’s and across a large part of Europe, and the sky grew so dark that candles had to be lit in the daytime. John Henry Newman, not yet a cardinal, who though believing in the two papal dogmas had thought it “inopportune” to define them, wondered whether these extraordinary phenomena were a sign that “our great Lord was angry at us.” Presumably, he was speculating that the bishops were committing the sin of tempting God by invoking the Church’s power to define dogma without (as he supposed) true need. Yet when one remembers how Scripture and the saints attribute to the evil spirits a power to stir up storms, one may believe, on the contrary, that it was the enemy of mankind who was enraged to see so magnificent a declaration made, on that far-off summer’s day, of the prerogatives of Christ’s universal vicar.
After all, a dogmatic definition by the Church, duly accompanied with anathema against those who deny it, is always, in itself, a splendid thing: a monument to the truthfulness of God, who can neither deceive nor be deceived, and who has communicated some portion of His infallibility to men. Even on the natural level, such a definition stands, against all the skeptical philosophies, as a reminder of the capacity of the human mind to know what is, and to express it in words that will never need to be reformed or corrected. On the supernatural level, a definition of dogma reassures us that we are not in this world like children adrift on a sea of uncertainty, and that God has told us what we need to find our way home.
What is the meaning of papal infallibility? It does not mean that a pope can never err when speaking about religion. Nor even, contrary to the opinion of some who publish their thoughts on theological matters today, does it mean that a pope can never commit the sin of heresy. This last point was expressly touched on at the Council of 1870 by Bishop Vincent Gasser, the Relator charged by Pope Pius IX with answering any questions and objections raised by the conciliar fathers about the text on which they had to vote. In a speech to the assembled bishops, Gasser described as “extreme” the opinion put forward by the 16th-century author Albert Pigghe, that a pope could never fall into heresy. Pigghe, sometimes known by the Latinized form of his name, Pighius, had argued that while a pope could err as a private person, and could from ignorance teach something incorrect while acting as a “private doctor” — for example, in a book published under his pre-papal name — he would never fall into heresy or teach a heresy. Gasser noted that some of the council Fathers were upset with the proposed dogma, since they were under the impression that it was identical to Pigghe’s view. Gasser, however, repudiated this suggestion and stated that the document on which they were being asked to vote by no means taught this “extreme” position:
The Deputation [that is, the group of bishops charged with drafting the document] is unjustly criticised, as if it wished to raise an extreme opinion, that of Albert Pigghe, to the rank of a dogma. The opinion of Albert Pigghe, which Bellarmine indeed describes as ‘pious and having some plausibility’, was that while a pope as an individual man or a private teacher could err from some kind of ignorance, he could never fall into heresy or teach heresy. … It is obvious that the doctrine contained in the schema is not that of Albert Pigghe. 
In other words, the dogma of papal infallibility leaves unresolved the question of whether a pope can fall into heresy privately or even express heresy in some public statement.
Later in the same speech, Bishop Gasser considered the latter point in more detail. The proposed dogma does not mean that a pope would be infallible, he explained, whenever he is speaking about faith or morals in a context in which only a pope could speak. As examples of such a context, we might mention papal Christmas messages Urbi et Orbi, or even encyclicals or apostolic exhortations addressed to all the bishops of the world. Gasser told the conciliar fathers:
Not just any way of proposing doctrine is sufficient, even when the Pontiff is exercising his supreme office of shepherd and teacher. It is necessary that the intention of defining doctrine be manifest, and of putting an end to uncertainty about some doctrine or matter to be defined, by giving a definitive judgement and proposing that doctrine as something that the universal Church must hold. 
It is not sufficient, therefore, that a pope show a desire to make Catholics favour this or that position: he must make it clear that all the faithful are obliged to assent to some clearly articulated doctrine, if they want to remain ‘Catholics in good standing’. This is what it means to speak ex cathedra, ‘from the throne’. And in the history of the Church, the Roman pontiffs have done this often, as anyone may see for himself by consulting a copy of Denzinger. Gasser went so far as to say that thousands of definitive judgements have been issued by the apostolic see. 
The definition of papal infallibility marked the final, happy triumph of the Church over the “conciliarist” movement that had begun in the later Middle Ages, and which had sought to subject popes to ecumenical councils. Why, then, did a man of the moral and intellectual stature of Newman think it would be inopportune to define the dogma? He feared that at that particular point in history, such a definition would upset the delicate balance among the different organs by which truth is taught within the Church — the papacy and the episcopacy and, in dependence on them, theologians and parish priests. He feared a hypertrophy of the papacy at the expense of other parts of the mystical body.
Newman had a point. Human beings find it hard to keep a firm grasp of complementary truths or fine distinctions. Once the papal prerogatives had been put into so bright a light, it was perhaps inevitable that many Catholics would tend in practice to act as if a pope’s every word were an oracle, or as if the wisdom of his policies could not be questioned without disloyalty. One may wonder, also, whether the atmosphere fostered by the definitions of 1870 may not have led the popes themselves to act as if their monarchy were more absolute, or their infallibility more extensive, than they really are, to the point that Paul VI could seek to give the Church a whole new liturgy, and Francis can laugh when accused of heresy. Did Paul VI, as he sought to “reform” the Roman rite beyond recognition, unconsciously reassure himself: “This may seem like a bad idea, but I’m the pope, so nothing can go really wrong”?
Has the episcopacy, too, suffered in the long wake of Vatican I? It was not Pius IX’s desire to turn the world’s bishops into his vicars, and he repudiated Bismarck’s claim that the council had done so. Yet, given human weakness, there was always a danger that this might happen, at least to some extent — that bishops might imagine, perhaps unconsciously again, that they were vicars not of Jesus Christ, but of the pope, charged with making his policies and preferences their own. Hence, surely, the deplorable lack of reaction among the bishops to the novelties of Paul VI and to the modernism of Francis.
Was it also from being thus weakened in their sense of their own prerogatives that orthodox bishops came to depend too much on Rome to teach the unpopular doctrines, for example on sexual morality? While we were blessed with many fine papal encyclicals in the 19th and 20th centuries, it is not a healthy sign when letters from the Roman pontiff to the universal Church become the usual means by which orthodoxy is maintained among Catholics. The episcopacy is the normal means for doing this; the papacy exists to scotch errors that episcopal teaching has not been able to defeat. Whether the massive increase, in modern times, of papal documents directed to the universal Church is related as cause or as effect of a dearth of good episcopal teaching is a nice question.
Without embracing Adrian Fortescue’s ironical suggestion that a pope should not open his mouth at all unless he is doing so infallibly, one may reasonably expect that teaching documents sent by a pope to the whole Church will principally intend to settle definitively some doctrinal crisis. Otherwise, why bother? Ordinatio sacerdotalis, Pope John Paul II’s brief letter excluding the priestly ordination of women, is a good example of this. Papal documents offering only “non-infallible” teaching are another sign that the functions of the episcopacy have become partially absorbed into the papacy.
None of this means that Newman was right. Things could well have gone worse had the “inopportunists” triumphed a century and a half ago. Even armed with the two papal definitions, St. Pius X could hardly keep modernism at bay; how much less if they had been refused him? And would belief in the Assumption of the Blessed Virgin Mary have survived the modern decay of faith if Pius XII had not been able to rely on the defined prerogatives of his office to declare it as dogma?
On the whole, I think we may be not only proud of these two definitions in themselves, but grateful to God that they were defined when they were. Newman was a great man, but as Chesterton remarked in his biography of St. Francis, the great men can be wrong when the little men are right. We groan inwardly at the present humiliation of the apostolic see, but at least we know whence the remedy must come. Just as Pope Honorius I was condemned for heresy after his death by the 3rd Council of Constantinople, and Pope St. Leo II ratified this conciliar act, so it seems impossible that Pope Francis should not one day be condemned for the same crime (unless the Lord returns), by one of his successors speaking from the throne. When that day comes, it will be a splendid example of what Vatican I meant, and of what it didn’t mean, by the infallibility of the pope.
 Acta et decreta sacrosancti oecumenici concilii Vaticani (Coll. Lacensis, VII, 405-6): “Deputatio iniuste traducitur ac si voluisset extremam opinionem, scilicet illam Alberti Pighii, ad dignitatem dogmatis evehere. Nam opinio Alberti Pighii, quam Belllarminus vocat piam quidem et probabilem, erat quod Papa qua persona singularis seu doctor privatus ex ignoranti quadam possit errare, sed nequaquam in haerseim incidere vel haeresim docere. […] Apparet doctrinam quae habetur in schemate non esse illam Alberti Pighii.” Note that the scholastic term probabilis, when used to describe an opinion, does not mean ‘probable’, but ‘having some plausibility’. Contradictory statements may therefore both be probabilis.
 Ibid., 414: “Non sufficit quivis modus proponendi doctrinam, etiam dum Pontifex fungitur munere supremi pastoris et doctoris, sed requiritur intentio manifestata definiendi doctrinam, seu fluctuationi finem imponendi circa doctrinam quamdam seu rem definiendam, dando definitivam sententiam, et doctrinam illam proponendo tenendam ab Ecclesia universali.”
 Ibid., 401: “Iam millena et millena iudicia dogmatica a Sede apostolica emanarunt.”
Pauper Peregrinus (“Poor Pilgrim”) is the nom de plum of a Catholic priest and theologian.