Where does papal infallibility start and end?

Here is what Vatican I says about Papal Infallibility:

when the Roman pontiff speaks EX CATHEDRA, that is, when,
1 - in the exercise of his office as shepherd and teacher of all Christians,
2 - in virtue of his supreme apostolic authority,
3 - 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.

Therefore, such definitions of the Roman pontiff are of themselves, and not by the consent of the church, irreformable.

With this in mind, I have the following questions:

1 - What does #1 and #2 tangibly mean? Assuming it was on faith or morals, which of the following from the pope would be considered infallible?

-When the pope uses the words “Ex Cathedra”
-Proclamations at an Ecumenical Council
-Proclamation at a local council
-Apostolic exhortations
-Papal Bulls
-Public letters
-Statements at weekly audiences
-Statements at misc teaching engagements
-Statements at misc public appearances (i.e. while traveling and visiting other countries)
-Private letters
-Private confessional counseling
-Private counseling

2 - After following the criteria from above, if one runs into seemingly contradictory statements, how do we know which one is correct?

3 - How do we know if a doctrine is held by the whole church? Who interprets this?

4 - What does it actually mean to “define doctrine”?

5 - Is there an easy way to know exactly what is infallible? If so, what is it? If not, why is the doctrine of papal infallibility meaningful?

For example, in 1950, with Munificentissimus Deus, Pope Pius XII’s infallible definition regarding the Assumption of Mary, there are attached these words:

Hence if anyone, which God forbid, should dare willfully to deny or to call into doubt that which We have defined, let him know that he has fallen away completely from the divine and Catholic Faith.

In July 2005 Pope Benedict XVI stated during an impromptu address to priests in Aosta that: “The Pope is not an oracle; he is infallible in very rare situations, as we know”.[16] His predecessor Pope John XXIII once remarked: “I am only infallible if I speak infallibly but I shall never do that, so I am not infallible”.[17] A doctrine proposed by a pope as his own opinion, not solemnly proclaimed as a doctrine of the Church, may be rejected as false, even if it is on a matter of faith and morals, and even more any view he expresses on other matters. A well-known example of a personal opinion on a matter of faith and morals that was taught by a pope but rejected by the Church is the view that Pope John XXII expressed on when the dead can reach the beatific vision.[18] The limitation on the pope’s infallibility “on other matters” is frequently illustrated by Cardinal James Gibbons’s recounting how the pope mistakenly called him Jibbons.[19][20][21][22][23]

Catholic theologians in general hold that the canonization of a saint by a pope is infallible teaching that the person canonized is definitely in heaven with God.
Catholic theologians agree that both Pope Pius IX’s 1854 definition of the dogma of the Immaculate Conception of Mary and Pope Pius XII’s 1950 definition of the dogma of the Assumption of Mary are instances of papal infallibility, a fact which has been confirmed by the Church’s magisterium.[69] However, theologians disagree about what other documents qualify.vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_const_19641121_lumen-gentium_en.html

I believe most of your questions are answered in the Infallibility article in the Catholic Encyclopedia.

It starts at matters of faith and morals explicitly revealed to be infallible and it ends at heresy. The Pope, could not, for example, teach Sola Fide or any of what Luther thought, as dogma and claim to be infallible.

Thanks. A lot of that coincides with my current understanding.

The form of the communication doesn’t matter per se, so it’s impossible to say that all encyclicals or all bulls are infallible, for example.

The private communications can be discounted because they are not addressed to the entire Church. Ditto anything that advises on a merely local situation, or makes rules that are only to be followed in a certain time or place. (Mind, the Pope still has authority to make all kinds of decisions and rules without invoking infallibility, and is to be obeyed by the faithful unless he commands sin.)

“Ex cathedra” means “from the chair,” and means that the Pope is speaking as the Pope, not merely giving his opinion as a theologian or a priest or a human being. It’s not something the Pope says to indicate an infallible statement.

It doesn’t say “a doctrine that is held by the whole church”; it says “a doctrine that is to be held by the whole church.” What matters is that the Pope is proclaiming that a particular teaching is to be adhered to by all Catholics everywhere, not that every Catholic actually obeys.

To define doctrine is to set the parameters of acceptable belief within the Church, usually on a contested issue. The First Council of Nicea defined the relationship between God the Father and God the Son in terms that staked out the orthodox position in comtradistinction to the Arian position. The two most recently (and papally) defined Marian doctrines establish that no Catholic may deny the Immaculate Conception or the Assumption of Our Lady.

There is no infallibly-promulgated list of infalliblly-defined doctrines, though a fellow named Ludwig Ott has done a thorough job of trying to classify the various doctrines by their level of certainty. Anything he lists as “de fide” is likely to have been either defined infallibly by a Council or Pope or else a sufficiently ancient part of the Tradition that there’s been no significant opposition to it and this no need for a formal definition.

If you find what you believe to be a contradiction between two statements that seem to meet the criteria for infallible definitions, see what else the Magisterium has had to say on the topic before deciding that your belief must be correct.


There’s not a single mode of communication by which an infallible statement must be issued. In order to be considered infallible, a statement must follow the conditions below:
-It must follow the ex cathedra formula (which is a specific style and phrasing specified by Vatican I).
-It must be on faith or morals
-It must be of the Pope’s own volition (he must not be pressured by external forces)
-It must be addressed to the Church as a whole

2 - After following the criteria from above, if one runs into seemingly contradictory statements, how do we know which one is correct?

The point of infallibility is that infallible statements cannot contradict each other, because infallibility 100% guarantees truth.

3 - How do we know if a doctrine is held by the whole church? Who interprets this?

The hierarchical Church does.

4 - What does it actually mean to “define doctrine”?

It means what it sounds like: to define exactly what Catholic doctrine is.

5 - Is there an easy way to know exactly what is infallible? If so, what is it? If not, why is the doctrine of papal infallibility meaningful?

If a papal statement follows the aforementioned formula, it is infallible.

A popular misconception is that Catholics only need to assent to infallibly taught doctrines of the Church. That notion is simply false. Catholics must accept all doctrine, fallible and infallible.

awke #1 9/3/14 Where does papal infallibility start and end?
…which of the following from the pope would be considered infallible?
When the pope uses the words “Ex Cathedra”?
What does it actually mean to “define doctrine”?

Modern Catholic Dictionary
by Fr. John A. Hardon, S.J.

“EX CATHEDRA. The term commonly applied to the special and explicit exercise of papal infallibility. When the Pope speaks from the chair (cathedra) of authority, as visible head of all Christians, his teaching is not dependent on the consent of the Church and is irreformable. (Etym. Latin ex cathedra, from the chair.)”

So a Pope never has to use the words “ex cathedra” as they define **his action **as explained.

The dogma of papal infallibility in teaching doctrine was defined at Vatican I and approved by the Pope. Infallible definitions may thus be made by a Pope as in the dogma of The Assumption of the Blessed Virgin Mary, and doctrine is taught infallibly as explained below.

So that infallibility may be exercised by a pope alone, by an Ecumenical Council approved by a pope, and in an encyclical or Apostolic Letter.

How do we know if a doctrine is held by the whole church? Who interprets this?

Any doctrine or dogma is intrinsically to be held (assented to) by the whole Church, and there is no licence to dissent.

The three levels of teaching are:
**1) Dogma – infallible **(Canon #750.1) to be believed with the assent of divine and Catholic faith.
**2) Doctrine – infallible **(Canon #750.2) requires the assent of ecclesial faith, to be “firmly embraced and held”.
3) Doctrine – non-definitive (non-infallible) and requires intellectual assent (“loyal submission of the will and intellect”, Vatican II, *Lumen Gentium 25), not an assent of faith. [See the Explanatory Note on ATF by the Congregation for the Doctrine of the Faith]

**Answer by David Gregson of EWTN on Nov-22-2002: **
“You are correct in stating that the Pope exercises his charism of infallibility not only in dogmatic definitions issued, ex cathedra, as divinely revealed (of which there have been only two), but also in doctrines definitively proposed by him, also ex cathedra, which would include canonizations (that they are in fact Saints, enjoying the Beatific Vision in heaven), moral teachings (such as contained in Humanae vitae), and other doctrines he has taught as necessarily connected with truths divinely revealed, such as that priestly ordination is reserved to men. Further details on levels of certainty with which the teachings of the Magisterium (either the Pope alone, or in company with his Bishops) may be found in Summary of Categories of Belief.”

So a follow-up question: What are some papal infallible statements made prior to Vatican I?

Papal infallibility started with Peter and will end with the last Bishop of Rome.

You may find helpful **The dogmas of the faith **at theworkofgod.org/dogmas.htm

The most notable one (and one that everyone agrees fits the definition) is the 1854 definition of the dogma of Mary’s Immaculate Conception.

If it’s true that formal canonizations fall under the protection of infallibility, then all of those.

Other than that, remarkably few attributable to the Popes themselves, because major dogmatic definitions are generally done in Ecumenical Council (a different exercise of magisterial infallibility) rather than by the Pope alone.

Are there some possible ones you’d specifically like to discuss?


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