What must a Catholic believe to be a Catholic? I know we must believe the articles in the Nicene and Apostolic Creeds and the Ex Cathedra statements about Holy Mary's Immaculate Conception and Assumption. What else must be believed, to be a practicing Catholic, according to the Catholic Church?

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    Just for clarity's sake, can you specify: 'must believe' for what? Commented Mar 11, 2021 at 0:36
  • I don't believe @anthony's question is a dupe, but the answer might be the same christianity.stackexchange.com/a/81090/4
    – Peter Turner
    Commented Mar 11, 2021 at 13:42
  • To be a Catholic
    – Eva
    Commented Mar 12, 2021 at 7:30

3 Answers 3


Truths absolutely necessary for salvation

The four truths absolutely necessary to believe for salvation are that

  1. "he [God] is", i.e., that God exists (Heb. 11:6)
  2. God "is a rewarder to them that seek him." (Heb. 11:6)
  3. the Second Person of the Trinity took on a human nature (Incarnation)
  4. God is Three Divine Persons in one God (Trinity)

Note: There is unanimous consent among Catholic theologians that truths #1 and #2 are absolutely necessary to be explicitly believed in order to be saved, but not all theologians (St. Thomas Aquinas, St. Alphonsus Liguori, et al. excepted) think that explicit belief in truths #3 and #4 is necessary; cf. True or False Pope p. 113 // PDF p. 128.

Truths necessary to be Catholic

To be Catholic, one must, as the asker writes, indeed "believe the articles in the Nicene and Apostolic Creeds and the Ex Cathedra statements about Holy Mary's Immaculate Conception and Assumption" (cf. the 4 Marian dogmas).


What must a Catholic believe?

Even though only two doctrines have been declared ex cathedra, there are many others that the church professes must be believed. Some of these are laid out in the 1998 Commentary on the Concluding Formula of the Professio fidei issued by then-Cardinal Joseph Ratzinger of the Congregation for the Doctrine of the Faith.

According to this document, many teachings are “irreformable” and “definitive” and as such can be seen as possessing the binding quality of an infallible doctrine, although not necessarily proclaimed ex cathedra. That is, they aren’t promulgated by the pope himself but by the larger magisterium of the church. The lineup of “irreformable” teachings—ones divinely revealed—include those regarding Jesus, Mary, sin and grace, the sacraments, the primacy of the pope, and the doctrinal formulations of the ancient creeds.

Thus the points of the Catholic faith are to be blindingly professed by all Catholics and must be believed in are as follows:

These points of profession are to be held as dogmatic truths by all Catholics in order to remain in the complete fullness of the Catholic faith.

There is some talk as to where Pope John Paul II wrote his Apostolic Letter Ordinatio Sacerdotalis in an ex cathedra manner. Some theologians do not think so, as the term infallible was not mentioned in the document but it must be noted that the infallible appears nowhere in any of the other infallible teaching documents either. Nevertheless it was strongly worded.

When Pope John Paul II said in Ordinatio Sacerdotalis that the church lacks the authority to ordain women, the word infallible did not appear. But the pontiff did say that this teaching should be "definitively held" and suggested that further debate was pointless. But on the issue of mandatory celibacy for clergy, Archbishop Pietro Parolin, the new papal secretary of state, noted recently that this is a matter of church discipline and not dogma, that the early church had married priests and that the matter of priestly celibacy is therefore open to discussion.

  1. Although the teaching that priestly ordination is to be reserved to men alone has been preserved by the constant and universal Tradition of the Church and firmly taught by the Magisterium in its more recent documents, at the present time in some places it is nonetheless considered still open to debate, or the Church's judgment that women are not to be admitted to ordination is considered to have a merely disciplinary force.

Wherefore, in order that all doubt may be removed regarding a matter of great importance, a matter which pertains to the Church's divine constitution itself, in virtue of my ministry of confirming the brethren (cf. Lk 22:32) I declare that the Church has no authority whatsoever to confer priestly ordination on women and that this judgment is to be definitively held by all the Church's faithful. - Ordinatio Sacerdotalis

The Church also acknowledges that some individuals may be incapable of making a proper profession of faith such as babies, small children and people with developmental disabilities, but that does not make them less Catholic! Intellectual impediments have always existed in the history of mankind and will always continue to be as such. We live in a world with a damaged human nature.

What Catholics Must Believe – Dogma, Doctrine or Discipline?

In this post I’ll explore what is meant by a Dogma, a Doctrine and a Discipline. I’ll explain where these terms derive from and how they form our faith. Finally to get specific, I’ll present a list of the 258 Dogmas of the Catholic Church (that I could find) that all the faithful must believe.

Simple Catholic Truth

In the previous post entitled “What Does It Mean To Be Catholic?”, I concluded that there existed a set of core beliefs that all Catholics must believe in order to be considered Catholic. For lack of time and space, I deferred a more detailed examination of what these beliefs are and where they came from until now. I will also include a final (optional) element of the Church’s faith teachings which are called Disciplines.

Taken together, Dogmas, Doctrines and Disciplines compose the framework of teachings of the Catholic Church. In sequence, Dogmas, Doctrines and Disciplines form a sort of descending classification of Catholic Christian truths. As we descend down this taxonomy, the relative importance and certainty of the teaching(s) decreases. For example, at the top of the list (Dogmas) we have absolute theological truths directly revealed to mankind by God. At the bottom (Disciplines) we have theological projections or opinions or practices that are useful, but otherwise can still be open to debate and change.


A Dogma is a truth revealed by God. Because they are revealed by God, Dogmas are essential elements of our faith and can not change. Dogmas are formally taught to us by the Church and as such are taught (infallibly) without error.

These Dogmas require the fullest and complete assent of theological faith by all members of the Catholic Church. In other (SCT) words, to be considered Catholic we must hold these to be true “beyond all doubt.”

The deliberate and obstinate denial of a Dogma of the faith is called heresy because this person rejects the revealed Word of God.

Examples of Dogmas: Divinity of Christ, Immaculate Conception, Real Presence of the Eucharist, Assumption of the Blessed Virgin Mary, Papal Infallibility.


Doctrines are also infallible teachings of the Church on matters of faith and morals but are not directly revealed by Christ. Doctrines are true but have been defined by Biblical, historical or logical extension of, or connection to, Dogmas. Doctrines can develop over time as the Church comes to understand them better—but Doctrines cannot change. No one—not even the Pope—has the authority to change Doctrine.

Every believer is therefore required to give “firm and definitive assent” to these doctrinal truths. In other (SCT) words, to be considered Catholic we must hold these to be true “beyond a reasonable doubt.”

Whoever rejects a Doctrine rejects the idea of the promise of Jesus and the power of the Holy Spirit to protect the teaching authority of the Church.

Examples of Doctrines: Resurrection, The Incarnation, Heaven, Holy Trinity, Priesthood reserved for males.

  • "church professes must be believed" Must be believed in order to what? Commented Mar 11, 2021 at 17:38
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    "Most theologians do not think so, as the term infallible was not mentioned in the document" It must be noted that 'this is an infallible teaching' appears nowhere in any infallible teaching document. Commented Mar 11, 2021 at 19:37
  • This answer is fundamentally incorrect. Most Catholics do not believe things like the assumption of Mary. They have no idea what it means, they have no idea that the Church teaches it, and they have no idea that it is a dogma. Nevertheless, they are Catholics in good standing.
    – zippy2006
    Commented Apr 13, 2021 at 0:26
  • @zippy2006 You can post an answer if you wish? ”Most Catholics do not believe things like the assumption of Mary.” Your sources please! The Apostolic Constitution of Pope Pius XII Munificentissiimus Deus as a Papal Constitution is binding to all Catholics! That said, you can expect that many self-identified Catholics and "Catholic" groups don't believe the doctrine. But, by virtue of the Papal Constitution, they're not "formally recognized by" or "in full communion with" the Catholic Church.
    – Ken Graham
    Commented Apr 13, 2021 at 0:28

Membership in the Catholic Church

In Joseph Ratzinger's 1986 article, "The Ecclesiology of The Second Vatican Council," he says:

A first important point was the dispute about membership in the Church which resulted following the encyclical on the mystical body of Christ which Pius XII had published on 29 June 1943. He had declared at that time that membership in the Church is tied to three presuppositions: Baptism, right faith, and affiliation with the legal unity of the Church.

That is, in order to belong to the Catholic Church one must be baptized, one must have right faith, and one must recognize the Roman Pontiff, bishops, etc. See Mystici Corporis Christi, #22 and #69.

"Right faith" and a note regarding positive beliefs

There is a strained assumption in the question, "What must be believed?" The Profession of Faith certainly includes the ancient creeds, but an answer like Ken's is fundamentally incorrect when it lists off a number of dogmas and doctrines as checkboxes that must be filled in. To take one example, the assumption of Mary does not need to be positively believed by someone in order for them to belong to the Catholic Church. Actually, most Catholics are unaware of this dogma and do not believe it.

As the Profession of Faith makes clear, what is required by "right faith" is not positive belief in dozens of doctrines, but rather assent to the Church and what She teaches. After the creeds, we are assenting to the Church. Membership does not require us to know, memorize, or recite all of the various dogmas and doctrines. It requires us to recognize the Church as authentic teacher. Someone who assents to the Church but is not aware of a particular dogma is still a Catholic, for if they discover that the Church teaches something, then they will believe it.

  • Can you post a Church directive that states Catholics are free not to believe in the Assumption of Mary. Whether some of the faithful do not believe in certain issues, does not change Ecclesiastical truths. I doubt most Catholics are unaware of this dogma, as you claim.
    – Ken Graham
    Commented Apr 13, 2021 at 1:00
  • I would recommend reading up on implicit faith vs explicit faith. For example, ST II.II.2.5.
    – zippy2006
    Commented Apr 13, 2021 at 1:18
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    In St. Thomas’s day, the Assumption had not been defined. It is now. On 1 November 1950, invoking his dogmatic authority, Pope Pius XII defined the dogma: By the authority of our Lord Jesus Christ, of the Blessed Apostles Peter and Paul, and by our own authority, we pronounce, declare, and define it to be a divinely revealed dogma: that the Immaculate Mother of God, the ever Virgin Mary, having completed the course of her earthly life, was assumed body and soul into heavenly glory.
    – Ken Graham
    Commented Apr 13, 2021 at 1:20
  • As usual, you seem unable to comprehend the answers given. Catholics are not required to positively believe every single dogma that has been defined. That is why the Profession of Faith does not list every doctrine of each of the three levels. That is why no catechumen is quizzed on such things, or made to memorize such things.
    – zippy2006
    Commented Apr 13, 2021 at 1:25
  • St. Thomas died in the 13th century. The dogma was defined in 1950. It has not "been definitively defined since St. Thomas's day." Goodbye, Ken. I hope @Eva learns something.
    – zippy2006
    Commented Apr 13, 2021 at 1:26

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