Is the Pope Infallible in Everything He Says?

The Short Answer

No. Papal infallibility does not mean that the Pope is always right, or that he cannot sin, or that his opinions, interviews and decisions are free from error. It means that when the Pope solemnly defines a doctrine of faith or morals for the whole Church, speaking ex cathedra (“from the chair” of Peter), the Holy Spirit protects him from teaching error. This has happened very rarely. The two definitions most often cited are the Immaculate Conception (1854) and the Assumption of Mary (1950).

People misunderstand infallibility in two opposite directions. Some critics, and some Catholics, assume it means every word a pope says is guaranteed true; then any papal mistake seems to disprove it. Others conclude that because popes have erred in some things, the papacy itself must have failed. Both rest on a misunderstanding of what the Church actually claims.

What the Church Does and Does Not Claim

The Church does not claim:

That the Pope cannot sin. Infallibility concerns teaching, not personal holiness. Popes go to Confession like everyone else.
That everything the Pope says is infallible. Homilies, interviews, books, letters and everyday decisions are not ex cathedra definitions.
That the Pope receives new revelation. The First Vatican Council taught that the Holy Spirit was promised to Peter’s successors “not so that they might, by his revelation, make known some new doctrine, but that, by his assistance, they might religiously guard and faithfully expound the revelation or deposit of faith transmitted by the apostles” (Pastor Aeternus 4).
That the Pope can teach whatever he likes. He is bound by Scripture and Tradition; he is their servant, not their master.
That non-infallible teaching can simply be ignored. Catholics owe “religious submission of mind and will” to the Pope’s ordinary teaching, “even when he is not speaking ex cathedra” (Lumen Gentium 25). That is respect and docility, not a claim that every such teaching is guaranteed free from error.

The Church does claim, in the words of the First Vatican Council (1870), that “when the Roman Pontiff speaks EX CATHEDRA, that is, when, in the exercise of his office as shepherd and teacher of all Christians, in virtue of his supreme apostolic authority, he defines a doctrine concerning faith or morals to be held by the whole Church, he possesses, by the divine assistance promised to him in blessed Peter, that infallibility which the divine Redeemer willed his Church to enjoy in defining doctrine concerning faith or morals” (Pastor Aeternus 4).

Notice the conditions: he must speak as shepherd and teacher of all Christians, with his supreme authority, defining a matter of faith or morals, to be held by the whole Church. All of them must be met.

Why Catholics Believe It

Christ promised that His Church would not fail

Jesus promised that “the gates of Hades shall not prevail” against His Church (Matthew 16:18), and that the Spirit would guide the apostles “into all the truth” (John 16:13). If the Church could solemnly bind all Christians to a false teaching about faith or morals, those promises would fail. Infallibility is simply the Church’s name for that protection.

Christ prayed for Peter’s faith

At the Last Supper, Jesus told Peter: “I have prayed for you that your faith may not fail; and when you have turned again, strengthen your brethren” (Luke 22:32). Peter was given a particular role in confirming the faith of the others. The Second Vatican Council echoes this, describing the Pope speaking infallibly “as the supreme shepherd and teacher of all the faithful, who confirms his brethren in their faith,” when “by a definitive act he proclaims a doctrine of faith or morals” (Lumen Gentium 25).

The Pope is not alone

The same Council taught that the bishops, when united with the Pope and teaching definitively together, especially in an ecumenical council, also share in this gift (Lumen Gentium 25). Papal infallibility is not a private power of one man, but a particular form of the protection Christ gave to His whole Church.

Common Objections

”Popes have been wicked men. How can they be infallible?”

Some popes, such as Alexander VI in the fifteenth century, lived scandalous lives. But infallibility has nothing to do with personal virtue. It concerns what a pope solemnly defines, not how he lives. It is striking that even the worst popes in history did not use their office to define false doctrine.

”Pope Honorius taught heresy.”

Honorius I (died 638) wrote letters that gave support to the Monothelite error, the claim that Christ had only one will, and he was condemned for it after his death by the Third Council of Constantinople (681). This is a real episode, and Catholics should not hide it. But Honorius’s letters were not solemn definitions binding the whole Church; they were private correspondence that failed to deal firmly with an error. The case shows exactly why the Church limits infallibility so carefully.

”Didn’t Paul correct Peter at Antioch?”

He did (Galatians 2:11), but for his conduct, not his teaching. Peter’s failure was withdrawing from table fellowship with Gentile Christians out of fear. Popes can make errors of judgement and can be rightly corrected for them. That is fully compatible with infallibility as the Church defines it.

”What about Galileo?”

Galileo was condemned in 1633 by a Vatican tribunal, not by an ex cathedra papal definition, and the judgement concerned a scientific question that the Church never defined as a matter of faith. The episode was a real mistake, and the Church has acknowledged it. It was not an exercise of infallibility.

”If a pope teaches something confusing or wrong, hasn’t he lost his office?”

Some Catholics, troubled by things recent popes have said, have concluded that the See of Peter is empty. The Church rejects this conclusion. A non-infallible statement that is unclear, or even mistaken, does not remove a pope from office, and no individual Catholic has the authority to judge the Pope: Church law states that “the First See is judged by no one” (Code of Canon Law, can. 1404). The opposite error, treating every papal word as beyond question, also misunderstands the Church’s teaching. Infallibility is narrow, and it is precisely its narrowness that makes it credible.

In Summary

Papal infallibility is not a claim that the Pope is always right. It is the Church’s belief that Christ, who promised His Church would not fail and prayed for Peter’s faith, protects the Pope from error when he solemnly defines a doctrine of faith or morals for the whole Church. Such definitions are rare. Everything else a pope says deserves respect, but not the same guarantee.

This article follows the method St Robert Bellarmine used in his Controversies*: state the question fairly, clear away misunderstandings, make the case, then answer each objection. Bellarmine treated infallibility at length in Book IV of his* De Romano Pontifice*, three centuries before the First Vatican Council defined it. See How We Answer Objections.*

Sources

Scripture: Revised Standard Version, Second Catholic Edition (Ignatius Press). Matthew 16:18; Luke 22:32; John 16:13; Galatians 2:11.
First Vatican Council, Pastor Aeternus (1870), ch. 4. ewtn.com
Second Vatican Council, Lumen Gentium (1964), 25. vatican.va
Catechism of the Catholic Church, nn. 888–892.
Code of Canon Law, can. 1404.
Third Council of Constantinople (681), on Honorius.
Pius IX, Ineffabilis Deus (1854); Pius XII, Munificentissimus Deus (1950).
St Robert Bellarmine, De Controversiis: De Romano Pontifice, Book IV.