We call these doctrines that all Catholics must accept de fide dogmas (or in some cases, ex cathedra). In a nutshell, though there are fine (sometimes very fine) distinctions that can be drawn, the Catholic is obliged, in the nature of the case, to accept all that the Church teaches. And that is because it is an act of faith to accept the notion that the Catholic Church is the One True Church established by Jesus Christ, historically continuous, universal, specially protected by the Holy Spirit for the purpose of passing down the apostolic deposit. Because we accept this in faith as Catholics, it is required that we accept all that the Church teaches. To do that is itself a result of supernatural grace from God.
Protestants don't look at it that way because, first of all, they deny that the Church is infallible. Once one does that, then it is a completely new rule of faith. For Protestants, that is sola Scriptura, or the idea that Scripture is the only infallible source of faith. Therefore, it is very difficult for a Protestant to accept the notion of submitting to a Church's teaching in faith, because for them, no Church has it completely right: only the Bible does that. They often see this as virtually a violation of people's right to think for themselves or violation of one's conscience.
It's not at all: it is a recognition of our own limitations, of something higher than ourselves: established by God, and of a Christian faith that includes acknowledgment of an authoritative, infallible Church. It takes faith, and faith is a supernatural gift granted by God through His grace and the assistance of the Holy Spirit. It's not mere reason, but can be supported by reason: like all Christian dogma.
Some Protestants use the word dogma, but they generally prefer the word doctrine. Protestants, to the extent that they are serious about historic Christian doctrine, do, of course, require a set of beliefs, too: just not as many as we do. I always use the example of Calvinists. A truly Calvinist denomination (Presbyterian, Reformed, in their traditional forms and belief-structures) would not allow a member to deny all five tenets of TULIP:
Total Depravity. . . or even two or three. They would no longer be considered members of the denomination, in terms of adherence to the creed of the group.
Perseverance of the Saints
I write entire books about Catholic distinctives. There is quite a bit. It's true that most Christians can agree on something like the Nicene Creed, but even there (and this is illustrative of the problem) one has to stretch quite a bit to include even Baptists, and anyone else who denies baptismal regeneration because of the clause: "We acknowledge one baptism for the forgiveness of sins". Thus we see that even on this broad level, there are huge differences.
There are always, it is true, people who join groups but disagree on some of the tenets. Catholics are not literally disallowed to have doubts and uncertainties in their head (the Church is not simplistic or naive about such things), but they are supposed to accept in faith all that the Church teaches, and certainly not openly oppose it, whether they fully understand everything or not.
As an analogy from my Protestant days, I attended Assemblies of God for four years (1982-1986), met many of my friends there, in the singles group, including my wife, got married there, started my old campus evangelistic ministry while there, and even decided to get "baptized" as an adult by full immersion in 1982, because that's what I believed at the time (in retrospect my true baptism was my Methodist baptism as an infant).
I never agreed with one of the 16 Fundamental Truths: the one (actually a combination of #7 and #8) that said everyone had to speak in tongues in order to receive the "enduement of power." This I felt to be expressly contrary to Paul's teaching about tongues, where he says that not all speak in tongues. Because of this, I never became a member. I was simply being honest: saying in effect: "I don't accept all 16 Truths that I am supposed to accept, so I won't become a member, but I agree with most everything else taught."
Actually, now looking at them again, I didn't realize that #12 on divine healing was as sweeping as it was. It almost promises a healing for any true believer, which is dangerously false teaching, that has caused untold misery and suffering and deaths in many cases, because people were misunderstanding how biblical healing works, and how often it should be expected (and I opposed that general teaching in writing in 1982; it is on my site today).
That gets back to our subject at hand: what to do when you disagree with something in the church you attend? If we say we are Catholics, then it should be understood that we accept all Church teaching, and are not reserving the right to express private judgment in dissent against the Church. To say that one is a member of the Assemblies of God is to accept the 16 Fundamental Truths, which is pretty much its confession. I did not, so I didn't become a member. I was not trying to be controversial; I was being true to myself, and, I think (then and now) to St. Paul's teaching, that I believe contradicts Assembly of God teaching.
Private judgment as a concept is itself a distinctively Protestant notion, basically stemming from Luther's dissent. See my papers:
The Logical Circularity and Hidden Premises of Sola ScripturaThe Catholic Church doesn't expect everyone to have perfect faith or knowledge and to fully understand every jot and tittle. But the Church expects a humble submission to that which has been established and held from the beginning (with development of doctrine and increased understanding along the way). See my articles:
Catholic vs. Protestant Conceptions of the Meaning and Consequences of Private Judgment (Including Lengthy Citations From Reformed Protestants Arthur W. Pink, Archibald Bruce, and Charles Hodge, Four Protestant Confessions, and Catholic John Henry Newman)
Private Judgment: Its Meaning and How it is Viewed by Protestants and Catholics
Refutation of the Common Protestant Polemical Charge That Catholics Inconsistently & Arbitrarily Apply Private Judgment in Accepting Catholicism (+ Discussion)
Protestant Ecclesiology and Epistemology is Always Ultimately Self-Defeating
Is a Catholic at Liberty to Selectively Choose Which Catholic Dogmas He Will Abide By?There are always , despite all these considerations, people who are "in" a group but not totally "of" it. Many times, they don't properly understand the teachings of their own group. Other times, they do understand full well, and disagree, as I did in the Assemblies of God. I did what I felt was the only honest thing, and did not ever become a member, because that would entail ostensible agreement with a tenet that I did not accept. It would be dishonest.
On the Scandal of a Church Outrageously Claiming to be a Church
On Whether God Could, Would, or Should Protect His Church From Doctrinal Error (vs. Dr. Edwin Tait: Anglican)
There is still a vast difference between the situation with Catholic dissenters or liberals or modernists and the situation found in Protestant denominations adopting wholesale liberalism and heterodoxy "officially." We have not done that. That is the difference. One can only look at what a group officially teaches. I wrote about this oft-made comparison, too: Dissident Catholics and Catholic Doctrinal Unity: A Contradiction?
I've given the more nutshell version of how a Catholic explains this very important consideration in the Catholic life. If a person really really wants to get into it (be forewarned!) there are nuances and complexities on a more "fine-tuned" level that are often vastly misunderstood and falsely portrayed by our esteemed "progressive" Catholics that we are blessed with (like mosquitoes) in our ranks. I wrote about this in the following (long!) paper: Vatican II: Is it Orthodox and Binding? / The Infallibility and Sublime Authority of Conciliar and Papal Decrees / Different Levels of Church Authority.
Also, the related question of conscience is dealt with in this paper: Conscience: The Catholic Church's (and Newman's) View.
To make this concept of "accepting all that the Church teaches" fairly simple and practical, Catholics are not at liberty to disagree with, for example, what is included in the Catechism of the Catholic Church. It was promulgated under Pope John Paul II in 1992, accompanied by the Apostolic Constitution Fidei Depositum, which stated in part:
The Catechism of the Catholic Church, which I approved 25 June last and the publication of which I today order by virtue of my Apostolic Authority, is a statement of the Church's faith and of catholic doctrine, attested to or illumined by Sacred Scripture, the Apostolic Tradition and the Church's Magisterium. I declare it to be a sure norm for teaching the faith and thus a valid and legitimate instrument for ecclesial communion. . . .
Therefore, I ask all the Church's Pastors and the Christian faithful to receive this catechism in a spirit of communion and to use it assiduously in fulfilling their mission of proclaiming the faith and calling people to the Gospel life. This catechism is given to them that it may be a sure and authentic reference text for teaching catholic doctrine and particularly for preparing local catechisms. It is also offered to all the faithful who wish to deepen their knowledge of the unfathomable riches of salvation (cf. Eph 3:8). It is meant to support ecumenical efforts that are moved by the holy desire for the unity of all Christians, showing carefully the content and wondrous harmony of the catholic faith. The Catechism of the Catholic Church, lastly, is offered to every individual who asks us to give an account of the hope that is in us (cf. 1 Pt 3:15) and who wants to know what the Catholic Church believes.