Q - What is the difference between a dogma and a doctrine? Are some optional? How am I to respond to the different kinds of Church teaching? I am confused.
A - Thanks for the question. Let us define our terms.
Doctrine = (from Jaroslav Pelikan) "what the Church believes, teaches, and confesses on the authority of the Word of God"
We need to break this definition down.
Believes means the ways in which the Church worships, lives, and prays.
Teaches means the explicit, day-to-day teachings of the Church.
Confesses means the solemn confession of faith including creeds and dogmas.
Dogma = Truths officially proposed by the Church as being part of or necessarily connected to Revelation in a binding, definitive way. They are infallible and are tied to the deposit of faith.
So, all dogmas are a sub-set of doctrine and in this way of defining doctrine, dogmas would fall under what the Church "confesses".
Another difference between the two is the level of authority the Church uses. When a dogma is formally confessed, the Church uses all of her authority.
Because there are different levels of authority that the Church uses, there are different responses that we are obligated to have.
To know what level of authority a doctrinal statement of the Church has, we must understand how the Church teaches. So, we must look for:
1 - Kind of document and manner of the wording used in the teaching. For instance, are they setting forth a dogma formally or rather an instruction or discipline that is less formal.
2 - Frequency of repetition is a clue. Has the teaching consistently be taught through the ages, in different documents or proclamations?
3 - The object of teaching is a clear clue. Is the teaching on faith or morals? Is it about a discipline? Is it about culture? etc.
Based on these different kinds of teachings we are called to have different responses. Here are the basics:
1 - INFALLIBLE DOGMA - We must hold all these truths with "divine and Catholic faith" (CIC 750) and if we hold "obstinate denial or obstinate doubt" (CIC 750) on these matters, then we commit heresy. In other words, we must hold these teachings as true.
Examples include Christ is both true God and true man (Nicea) and that Mary is assumed into heaven body and soul (Pope Pius XII).
2 - DEFINITIVE STATEMENT - These are matters that are closely connected to revealed truth. These must be "firmly accepted and held...when the magesterium proposes 'in a definitive way' truths concerning faith and morals, which even if not divinely revealed are nevertheless strictly and intimately connected with revelation." (Dupuis - "The Christian Faith" 181).
Examples include canonization of Saints and the canon of Scripture.
3 - ORDINARY TEACHING ON FAITH AND MORALS - these must have "religious submission of intellect and will" (CCC 892). They cannot be dispensed with just because they are not taught with more authority. This cannot just be an external conformity.
Examples include statements on when a human is considered "dead" and most of the teaching in Vatican II.
4 - ORDINARY TEACHINGS ON DISCIPLINE - Requires external conformity. In other words, even if we have an internal difficulty, we still need to follow the rules.
Examples include rules about fasting, married priests in the Latin rite and how Bishops are elected.
I hope this helps clear up some of the ambiguity, though I might have just thrown another wrench into the works.