Numerous times I have heard people say “The Church changed it’s mind about receiving the Eucharist in the hand, it can change it’s mind about other things. Some day they’ll say that contraception is okay.”
On this forum, I have seen people post the same sentiments, but I have not wanted to go off topic to explain how they are talking about two different things. Eucharist in the hand is a Discipline, Contraception is a Doctrine.
The Church uses Dogma, Doctrine, and Discipline to teach us about the way to heaven.
Dogma is a truth that is found in the Bible and has remained unchanged throughout the ages. A dogma taught by the Church is that Jesus is God. Another dogma is that sodomy is wrong. They are basic truths from the Bible that cannot be changed.
Doctrine is a truth defined by the Catholic Church that may have been speculated upon at one time, but has been ultimately defined by the Catholic Church. Doctrine does not change once it’s been defined. The Immaculate Conception and the Prohibition of Artificial Birth Control are Doctrines of the Church. The Church has studied the Natural Law and has made these conclusions. They are now set in stone.
Disciplines are rules or regulations that the Church practices. They are more like procedures. These can be changed. Things that fall under disciplines are: saying the Mass in Latin or English, altar girls, Designation of Holy Days of Obligation, married clergy, and removal of the altar rails.
The Church can change the way we go to confession, a discipline, but it can not change the fact that we are expected to go to confession, a dogma.
It may streamline the procedures for an annulment, a discipline, but it can not do away with annulment and what it means, doctrine.