Papal Infallibility: What It Is and What It Isn’t

The Doctrine That Embarrasses Everyone Equally

Papal Infallibility: What It Is and What It Isn’t

No Catholic doctrine is more misunderstood — by Catholics and non-Catholics alike — than papal infallibility. Ask a non-Catholic what it means and they will likely say: everything the Pope says is true. Ask a certain kind of progressive Catholic what they think of it and they will look embarrassed and change the subject. Both responses reflect the same misunderstanding. Papal infallibility is a precisely defined, narrowly scoped charism that has been formally invoked exactly twice in two thousand years of Church history. It is one of the most restrained doctrines in Catholic theology, not one of the most extravagant.

The doctrine was solemnly defined at the First Vatican Council in 1870, in the constitution Pastor Aeternus. The definition is careful to the point of being almost lawyerly: the Pope speaks infallibly when he speaks ex cathedra — from the chair, in his official capacity as pastor and teacher of all Christians — defining a doctrine concerning faith or morals to be held by the whole Church. Four conditions must simultaneously be present: the papal office, the universal address, the matter of faith or morals, and the explicit definition. Remove any one of the four and the infallibility charism does not apply.

What It Does Not Cover

The Vast Territory Outside Infallibility

The Pope is not infallible in his personal opinions. He is not infallible in his political judgments. He is not infallible in his administrative decisions. He is not infallible in homilies, interviews, in-flight press conferences, or casual remarks. He is not infallible in encyclicals as such — encyclicals can contain infallible teaching, but their genre does not make them so. He is not infallible in disciplinary decisions about the liturgy, the governance of the Church, or the appointment of bishops.

This is why a Pope can make imprudent decisions — and some have made catastrophically imprudent decisions — without those decisions being infallible. Pope Honorius I (625-638) was posthumously condemned by the Third Council of Constantinople for failing to clearly condemn the Monothelite heresy. Pope John XXII (1316-1334) preached that souls do not see the beatific vision until after the Last Judgment — a position directly at odds with Catholic teaching, which he eventually retracted under pressure. Bad judgment. Scandalous, even. Not infallible teaching.

The Two Formal Invocations

Papal infallibility has been formally and explicitly invoked precisely twice since 1870: the definition of the Immaculate Conception by Pius IX in 1854 (before Vatican I, but retroactively recognized as meeting the criteria) and the definition of the Assumption of Mary by Pius XII in 1950. Both were definitions of Marian dogma. In 155 years since the formal definition, not a single other invocation has been made. The Pope who most loudly claimed sweeping authority used the charism to talk about the Blessed Mother — twice.

The Biblical Foundation

Why the Church Believes This

The foundation is Luke 22:31-32, where Jesus says to Peter specifically: “Simon, Simon, behold, Satan hath desired to have you, that he may sift you as wheat: But I have prayed for thee, that thy faith fail not: and thou, being once converted, confirm thy brethren.” Jesus does not pray that all the apostles’ faith will not fail. He prays specifically for Peter’s — and He gives the reason: Peter has a unique office of confirming the brethren in the faith. The prayer of the God-man, by definition, is efficacious. Peter’s faith, in the exercise of his confirming office, will not fail.

The second foundation is John 16:13: “But when he, the Spirit of truth, is come, he will teach you all truth.” The Spirit of truth is given to the Church to preserve her in the truth. Infallibility is the negative expression of this positive gift: the Church cannot solemnly define as true something that is false. The charism is not a positive inspiration that makes the Pope a new prophet or a revealer of new doctrine. It is a negative protection that prevents the Church from formally binding the conscience of the faithful to an error in faith or morals.

The Protestant objection to infallibility is that it makes the Pope into a second Christ or a fourth Person of the Trinity. This confuses infallibility with inspiration. The biblical authors were inspired — moved by the Holy Spirit to write what He intended. The Pope is not inspired in this sense. He is preserved from formal error in a specific and narrow exercise of his office. The charism is entirely negative and entirely conditional on the four requirements. It is a protection, not a revelation.

The Development of the Doctrine

Newman, Vatican I, and the Critics

The definition at Vatican I provoked an immediate crisis. A significant minority of bishops, including many Germans and Austrians, voted against the definition — not because they denied the substance of the doctrine but because they thought the timing was politically inopportune, given the hostility of the European powers. After the vote, most submitted. Those who did not formed the Old Catholic Church, which still exists today as a small schismatic community.

John Henry Newman, who had already converted to Catholicism twenty years before the Council, was deeply uneasy about the definition — not because he denied papal primacy but because he worried about the precision of the language and the political pressure driving the vote. After reading the full definition, he was satisfied: the four conditions were so strict that the doctrine was far more limited than its enemies claimed. He wrote privately that he could now “with great relief” accept the definition, as it was far less sweeping than what the extreme ultramontanists had wanted.

“Papal infallibility is not the claim that the Pope is always right. It is the claim that when the Church, through her supreme teacher, solemnly binds the faithful to a doctrine of faith or morals, the Holy Spirit prevents her from binding them to a lie. It is, at its core, a claim about God’s faithfulness to His Bride — not a claim about the Pope’s cleverness.”

Why It Matters

The Alternative Is Worse

The real question is not whether papal infallibility is convenient or politically palatable. The real question is what the alternative is. If the Church has no infallible teaching office, then Christian doctrine is ultimately up for grabs. Every generation can revise the previous generation’s theology. Every council can contradict the last. Every pope can walk back his predecessor. The faith becomes a moving target — which is precisely what has happened to every Protestant denomination, which today accepts divorce, contraception, women’s ordination, and same-sex unions, having once rejected all four.

The Catholic claim is not that infallibility makes the Church comfortable or powerful. The claim is that it makes the Church trustworthy. If Jesus Christ promised that the Spirit of truth would guide His Church into all truth (John 16:13), and if He promised that the gates of hell would not prevail against it (Matt 16:18), then there must be some mechanism by which the Church is preserved from formally teaching error. Infallibility is that mechanism — narrow, precisely defined, and deployed in two thousand years exactly twice. The charism has been almost ostentatiously restrained. One could reasonably argue it has been used too little, not too much.

Share on Social Media