Few elements of Catholicism are as broadly misunderstood by Catholics and non-Catholics alike as the doctrine of papal infallibility. This teaching refers to the inability of the Church to formally teach error—a gift owing to divine guidance. Within specific contexts, infallibility encompasses the college of bishops. The Second Vatican Council states in Lumen Gentium that “although the individual bishops do not enjoy the prerogative of infallibility, they can nevertheless proclaim Christ’s doctrine infallibly.” Furthermore, the bishops’ authority is even clearer when they are all “gathered together in an ecumenical council.” Uniquely, however, as the head of the college of bishops and the Vicar of Christ, the pope maintains individual infallibility, as granted by Christ.
Papal infallibility refers only to a specific subset of teachings provided by the pope to the Church. According to Dr. Jeffrey Mirus of EWTN, “When the Pope intends to teach by virtue of his supreme authority on a matter of faith and morals to the whole Church, he is preserved by the Holy Spirit from error.”
Additionally, infallibility must always be made explicitly clear. Canon Law 749 §3 states, “No doctrine is understood as defined infallibly unless this is manifestly evident.” As such, papal infallibility excludes differences between the private theological opinions of popes. It also does not apply to personal actions of the pope. There have been a number of popes throughout Church history whose actions, public and private, have directly violated tenets of Catholicism. Such actions are not infallible, and it remains possible for the pope to live in a state of personal sin. His infallibility extends only to specific instances within the tenets of the Church.
Although papal infallibility was not formally defined within the Church until the First Vatican Council in 1870, it has always existed implicitly throughout Church history. The idea has its roots directly in the teaching of Christ, as Scripture says, “And so I say you you, you are Peter, and upon this rock I will build my church. …Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven” (Mt 16:18-19).
Jesus knew of the fallibility of the Apostles as individuals. One only needs to look four verses later, when He rebukes Peter, saying, “Get behind me, Satan! …You are thinking not as God does, but as human beings do” (Mt 16:23). As such, Christ’s proclamation regarding the binding and loosing came with the understanding of His holy guidance of the successors of Peter and the Apostles.
Such explicit and powerful authority must be coupled with the inability to teach error, thanks to the enlightenment of the Holy Spirit. This has been understood throughout the history of the Church. Well over a millennium before the formal establishment of papal infallibility, St. Cyprian famously wrote in his Epistulae, "Would heretics dare to come to the very seat of Peter whence apostolic faith is derived and whither no errors can come?”
A doctrine must fall into question or confusion for an infallible pronouncement to become necessary—and the understanding of papal infallibility was generally unquestioned until its formal definition during Vatican I.
The role of the pope extends well beyond infallible pronouncements. Still, we are encouraged by his ability to teach the Church without making an error. Through this structure, we may remain certain of the fulfillment of Scripture, as it is written, “But if I should be delayed, you should know how to behave in the household of God, which is the church of the living God” (1 Tim 3:15).