Catholic categories of mandatory belief/behavior

Can someone explain in Catholicism which required teachings and practices are dogmas, disciplines, Tradition, or something else. If possible, please differentiate between which ones are permanent and will never change and which ones may possibly change and are not infallible.

For example, what category do the following fall under?

  1. Whether all priests will ever be allowed to marry.
  2. Eating fish on Fridays.
  3. All male priesthood (no women priests).
  4. Sunday obligation is considered mortal sin.
  5. Genuflecting in church
  6. Feast days and dates given for them.
  7. Protestants are viewed as “separated brethren” but considered Christian by the Church
  8. Birth control seen as mortal sin.

Use others as needed to help differentiate. Thanks a lot! I am not necessarily opposed to any of these things but wanted to better understand what category they fall under and if they are incapable of changing or not.

Wow…you’ve made a perfectly reasonable post asking reasonable questions, and I think you’ve opened up every single can of worms at the same time.

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I got some coffee cooking over the fire! It’s gonna be a long night so drink up. :coffee::coffee::coffee::coffee:


I’ll give it a try.

That’s a discipline, not a doctrine, so the Church could change its stance and allow married priests in the future if it so desires.

That’s a form of penance that Rome allows each Episcopal Conference (a country’s Conference of Bishops) to decide how to implement. Hence, it can vary from country to country.

That’s a universal doctrine (not a discipline) so it’s not going to change.

Very bad wording on your part. The obligation to attend Mass each Sunday is NEVER a mortal sin. I think you might of meant: is missing a Sunday Mass a mortal sin. Well, that has changed over the years. Before it was definitely considered a mortal sin to miss a Sunday Mass with no legitimate excuse in regards to why one didn’t attend Mass. After Vatican II it is still considered a grave sin to miss a Sunday Mass, but not automatically considered a mortal sin (though missing many Sunday Masses most likely becomes a mortal sin).

Like the Friday penance, it varies based on the dictates of each countries Bishop’s Conference.

The dates are set by Rome, but the observation of them, like the Friday penance and genuflecting, varies based on the dictates of each countries Bishop’s Conference.

Those who baptize in the name of the Father, Son and Holy Spirit (Trinitarian Christians like the Lutherans and Methodists) are considered Christians by the Church.

I’m not sure what’s the Church’s precise teaching on this.


This is a matter of discipline. The Eastern Churches, both Catholic and Orthodox have a tradition of a married priesthood. As a matter of fact, so did the West.

A disciple.

This is a Tradition of the Church. Not sure if the Catholic Church has “dogmatically” taught this but you won’t be seeing a woman priesthood.

Not sure :thinking: I’m assuming when you ask about Catholicism you are referring to the Latin Church. We Byzantines see things a little differently.


Most feast days, such as The Nativity of the Theotokos, which is coming up September 8 and is one of the 12 Great Feasts of the Eastern Churches, happened organically in local (diocese) Churches and those Feasts and dates spread and became Universal feasts. The date for Pascha was set at the First Council in Nicaea.

Vatican II

Tradition guessing?

Hope this helps.

How did I do people :joy:


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I will try to address a couple where I think the answers already have not sufficiently covered it:

This is badly worded, as someone else said. Sunday and holy day Mass obligation is a Precept of the Church, in other words it is one of a few broad moral and ecclesiastical laws that set forth the minimum duties Catholics need to perform. It is not automatically a mortal sin if you miss Mass on Sunday, and the teaching on this has not changed contrary to what someone else said. It depends on why you missed; obviously if you missed because you were too sick to go, or because the nearest Mass was 200 miles away from you, then that’s not a sin, whereas missing because you simply decided not to bother is a grave sin and might possibly be mortal if committed with full knowledge and deliberate consent.

Following whatever fast and abstinence laws are put in place by the Church in one’s diocese, eparchy etc is also a Precept of the Church. These fast and abstinence practices vary somewhat depending on if you are Western Catholic or Eastern Catholic and depending on your geographic location (for example, Latin Catholics in USA have different Friday abstinence rules than some other countries). Some of the fast and abstinence rules are handed down from Vatican level, but many are left to the local bishops (for a country or for a particular diocese) to determine. This is because the Church realized at some point that the dietary needs and issues for one group of Catholics in geographic area A might differ greatly from a group in area B, due to factors like available sources of food and the prevailing work in an area which determines the number of calories somebody needs to keep from illness or injury.


This is another one that is badly worded. First, the Church’s concern is with artificial birth control, which would include things like condom, diaphragm, IUD, BC pills, etc. The Church does not object to natural family planning (NFP) which basically means that a couple abstains from sex during a woman’s fertile time.

Second, the use of artificial birth control is a grave sin; in order for it to be mortal, the conditions of full knowledge and consent also have to be met. We don’t have automatic “mortal sins”, there must always be knowledge and consent.

The Church teaching against artificial contraception is traditional going back to the early years of the Church. It was reaffirmed in the 20th century in response to advances in technology of artificial birth control (e.g. The Pill) and some Protestant Churches deciding to change their own teaching to allow artificial birth control. Most notably, the Papal encyclical Humanae Vitae by St. Pope Paul VI in 1968 reaffirmed the Church’s traditional teaching against artificial birth control.


Again, let’s clarify the wording here.
The Church has always recognized those who receive Trinitarian baptism as Christians. Many, but not all, Protestant Churches practice Trinitarian Baptism, so one cannot make a blanket statement that every member of every Protestant Church is considered “Christian” by the Catholic Church. Some are and some aren’t.

Focusing on the Protestants who would be considered Christian due to receiving a Trinitarian baptism, the issue has always been whether they were in communion with the Church and thus saved (as the Church has always taught and continues to teach that there is no salvation outside the Catholic Church). Prior to Vatican II, Protestants (Christian or not) were generally referred to as “heretics” and considered to be not in communion with the Church. Some theologians and clergy/ religious nevertheless worked towards building bridges in this area. The term “separated brethren” was actually coined by Blessed Dominic Barberi, a Passionist priest/ preacher/ theologian in England in the early 1800s who helped to convert soon-to-be-Saint John Henry Newman from Anglicanism to Catholicism.

Vatican II in the early 1960s recommended getting rid of terms like “heretic” and “schismatic” and using “separated brethren” instead to refer to non-Catholic Christians. Nowadays we are more likely to just say “non-Catholic Christian”. This does NOT reflect any change in who we consider Christian; the requirement has always been Trinitarian baptism. It just reflects a change in attitude as we are more ecumenical and kinder towards Protestants nowadays for various reasons (one being, IMHO, that they currently aren’t seen as being as big of a threat to the Church at this point as they used to be).

For the major feasts like the Nativity and Easter/ Pascha, this is a combination of tradition and ecclesiastical rules. Believe it or not, in the early Church there were extremely heated debates over things like how to determine the date to celebrate Easter/ Pascha. Even today, the Eastern and Western Churches have some differences on dates for certain feasts.

For feasts such as saints’ days, the calendars have already been changed and updated a number of times by various Popes, and there are also calendars specialized for a particular country or religious order. The tradition is to celebrate a saint on the day of his or her death, but this is sometimes adjusted to use the saint’s birthday or other significant day.

I think it’s safe to say that the calendars are not written in stone and could be changed again by the authority in charge of whatever calendar we are discussing.


My apologies on the wording of the Sunday obligation and birth control questions. I was groggy from having taken an antihistamine last night for an allergy and should’ve waited until my mind was more clear.
I think PeterT deciphered what I was after If any more clarifications are needed, let me know.

As I previously mentioned, I don’t necessarily question or challenge any of these practices/beliefs/disciplines. Just wanted to see which are considered permanent and which could potentially change down the road if the Church determined. Thanks for the answers received. Much appreciated.

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Let me make a couple of suggestions to you, since I’ve been reading many of your threads over time. (In other words, I’m not trying to criticize you here, just trying to help.)

You started out by asking a longer version of a question that needed simplified. You used several words that don’t particularly belong together for the sake of the information I believe you were after. In short, you want to know for your list, which things are doctrine (unchanging teachings) and which are discipline (changeable practice). The rest of the words (Tradition, infallible, dogma, etc.) are adjectives and detail-oriented terms that are just muddying up the waters for you right now.

Second, your list almost has the opposite effect - far too general to be able to concisely answer. E.g., “genuflecting in church” - what about it? There are details and nuances that can make this phrase a discussion of BOTH doctrine and/or discipline, but assuming the simplest interpretation of what you may be asking, I think the posters above addressed it sufficiently well.

My point is this (and again, no offense - trying to help you learn how to better get the information you seek here next time): many non-Catholic folks have a tendency of using words in improper context like “infallible” and “dogma” and then the conversation becomes confused and questions/answers less clear. There’s also a tendency to just point out Catholic “stuff” as if it were obvious what the question is, but there’s no question at all. For instance, one of my Protestant neighbors once said to me, “Do you know Catholics use candles?” My response was a dumb look… did he mean the votives we light, the altar candles, the sanctuary lamp, candles I light at home when the power goes out, or what? And what, exactly, was his question/objection to any of those candle uses anyway? He never asked or clarified his concern. Don’t shorthand your question and let us guess what you mean. Help us help you. :grin:


It is still a mortal sin to miss Mass on even one Sunday or Holy Day of Obligation, if you were reasonably able to get there, and there were no excusing cause. It does not have to reach the threshold of two, or three, or more instances of having deliberately missed Mass.

That said, “excusing causes” are broader than faithful Catholics generally think they are. Jone’s Moral Theology, which is a safe guide to matters such as this, lists the following things that can be reasons not to go to Mass:

I have said elsewhere on this forum that it seems to me the terms “grave”, “serious”, and “mortal” have become conflated in recent years. In times past, it was very clear-cut — a “mortal sin” was one that is worthy of eternal punishment, and a “venial sin” falls short of that. Some acts are mortally sinful in and of themselves, but if they are committed with any doubt as to full knowledge (“sufficient reflection”) and full consent of the will, they may be judged venial.


I do sympathize with you. As a Non-Catholic coming in and reading detailed conversations here on any one of these topics, I could easily see how some of these threads would elicit the response “What the…!” Honestly, even as a Catholic adult convert who went through RCIA, I’m still learning new things here.

To be helpful, I’d say that there are many distinctions to be made here. The first is the difference between religious and diocesan priests. Religious priests join orders like the Benedictines, Dominicans, Jesuits etc. There first vocation is really to their order, and priesthood may be their second vocation. Not all non lay members of these orders are priests. Will priests in these orders ever be allowed to marry if the discipline of celibacy were relaxed. I’d say it is very unlikely that these orders would change their “tradition” of celibacy even if most diocesan priests could marry.

The Jesuits may have discussed allowing their members to marry in the late 60’s and 70’s in their main general council if you belief some of the Martin Malachi’s rumors in his book about the Jesuits. Malachi went on to describe crackdown from the Pope upon hearing this…a long story from one of Martin Malachi’s poorly written books. Who knows if it is completely true?

The second distinction worth mentioning, is “What exactly is Catholic clergy?”. Today it means taking holy orders. There three types of holy orders. They are Deacon, Priest, and Bishop. They are all part of the same holy orders. Married men are eligible to become Deacons. The church has a long history and tradition of Deacons. Saint Francis of Assisi was a Deacon not a priest. There has been a Doctor of the church that was a Deacon. Part of the discussion about married priests includes expanding the role of Deacons.

I hope this helps!

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#3 and #8 are doctrinal, although #8 needs to be clarified— contraception, not birth control, is grave matter.

#7 isn’t really a doctrine per se as it pertains to protestant groups, but actually derives from the doctrine on valid baptism. All those who have been validly baptized are Christians.

The rest are disciplinary. However, again you have some things wrong. There is no obligation to eat fish on Friday. Rather there is an obligation to abstain from meat.

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ZP, I suggest no guessing. You have confused a few matters.

The male priesthood is indeed doctrinal, and it was definitively defined by Pope John Paul II in Ordinatio Sacerdotalis.

Baptized non-Catholics being Christians is not “Vatican II”. It has nothing to do with Vatican II. That was settled in the second century.

And, contraception being intrinsically evil is a doctrine.


What the Church teaches is that contraception is intrinsically disordered and each marital act much be per se ordered to unity and procreation.

“Artificial” has nothing to do with it. And the Church does not teach birth control is immoral, only that contraception is an immoral means of doing so.

By artificial birth control I mean contraception. Thanks for clarifying it. I don’t use it and fortunately never had to think about it much, so never paid attention to the correct words.

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I’m Byzantine Catholic. I have not idea what the Latin Church has dogmatically said about the issue. As I posted, you won’t be seeing women priests.

The OP asked about “Protestants are viewed as ‘separated brethren’ but considered Christian by the Church” and this is from VII.

As I said, I’m Byzantine and I assume this is a Tradition of the Church.

Thanks for your response.


The Pope is the Pope of the universal Church, that includes both the Byzantine and Latin. IOW, he is your pope too.

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Yes, this. :grinning: However, the answers given by everyone have been very helpful in understanding how different things are categorized in Catholicism, which can appear complicated to a non-Catholic, at least to this small town boy.

If I were a Catholic, at least until I got the hang of it, I think I would be worried about sins of omission or commission related to some of these things I mentioned, as well as a few others I haven’t mentioned that I am curious about, such as if it is a sin for a Catholic to never do the Rosary.

I now understand why there appear to be so many scrupulous Catholics and why I see different threads on CAF about whether this or that action is a mortal sin or not, especially since salvation in Catholicism apparently hinges on knowing and following many rules and regulations. Thankfully, the saving grace of Catholicism (to me) seems to be there is abundant forgiveness in cases where people break rules unknowingly or out of ignorance.

For example, when I was in high school many moons ago, I attended a Mass with a Catholic buddy of mine after I had a spiritual awakening and made a life commitment to follow Jesus and he did, too. However, I was not Catholic. He invited me to go up and take the Eucharist with him, which I did. I remember him saying, you can take it on one condition – that you believe this is really truly the body and blood of Jesus. I told him, "If they say it is, I believe it too because I want more of Jesus in my life" so I took it with him, only to learn many years later from a different Catholic that what I did could have caused my death and was a grave sin. Therefore, I’ve been a little gun shy of Catholicism and all of its rules and regulations ever since and am just now broaching the subject again.

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You’re right, my Metropolitan Bishop is in communion with the Pope of Rome.


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