The Roman Catholic teaching on the infallibility of the pope is often misunderstood by Roman Catholics and Protestants alike. For that reason, it’s especially important for us to have a correct understanding of what the Roman Church actually teaches about papal infallibility.
Papal infallibility was not made an official dogma of the Roman Church until 1870, at the First Vatican Council (a.k.a., Vatican I). Before 1870, many Roman Catholics did believe that the pope possessed some level of infallibility; however – and importantly – many Roman Catholics did not believe in papal infallibility. Before papal infallibility was defined dogmatically, debate and disagreement on the topic was allowed within the Roman Church. After 1870, however, to be a Roman Catholic one must necessarily affirm papal infallibility. The decision to affirm papal infallibility was met with intense debate within the Roman Church, and there were many Roman Catholics who disagreed so strongly with the dogma adopted in 1870 that they split from the Roman Catholic Church and formed what is called the Old Catholic Church.
The official teaching of the Roman Catholic Church on papal infallibility is found in The First Dogmatic Constitution on the Church of Christ. The most important statement is the following:
“we teach and define that it is a dogma divinely revealed: that the Roman Pontiff, when he speaks ex cathedra, that is, when in discharge of the office of pastor and doctor of all Christians, by virtue of his supreme Apostolic authority, he defines a doctrine regarding faith or morals to be held by the universal Church, by the divine assistance promised to him in blessed Peter, is possessed of that infallibility with which the divine Redeemer willed that his Church should be endowed for defining doctrine regarding faith or morals; and that therefore such definitions of the Roman Pontiff are irreformable of themselves, and not from the consent of the Church. But if any one—which may God avert—presume to contradict this our definition: let him be anathema” (translation from Philip Schaff, Creeds of Christendom Vol. 2, 270–271)
Things to note from this statement: First, it is dogma and to disagree with it is to be anathema (i.e., cursed / excommunicated). Second, when a pope speaks infallibly, he does so from his own authority, does not need approval from a council, and cannot be second-guessed or corrected. But third, the pope’s infallibility is not universal. The pope saying “Pepsi is better than Dr. Pepper” is not an infallible statement, nor are any off-the-cuff remarks. The pope is infallible only when 1) he is deliberately speaking from his authoritative position and 2) he is defining a doctrine related to faith or morals that is applicable to the whole Church.
The claim of the Roman Church, even with the limitations in mind, is quite bold (some would even say, audacious), but here’s where things get especially interesting: the Roman Church today actually downplays the dogma of papal infallibility. The plain reading of the text from Vatican I is that the pope is only and always infallible when the necessary conditions are met. But many of the authoritative statements of popes throughout history put the Roman Church in a very difficult, if not impossible position – one reason the Old Catholics broke away from Rome. The Roman Church knows this too, which is why they insist that popes have spoken infallibly only twice in history: the defining of the dogmas of The Immaculate Conception of Mary and The Assumption of Mary.
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