Dissent In the Church
FATHER ROBERT J. LEVIS COMMENTS ON DISSENT IN THE CHURCH
To sum up the official teaching of the Church:
l. If it is a teaching proclaimed by the extraordinary magisterium, a good Catholic must assent under pain of heresy.
2. If it is a teaching proclaimed by the ordinary magisterium, e.g. the 10 Commandments, a good Catholic must assent under pain of serious sin.
3. If it is a teaching seriously proclaimed by the magisterium in a non-infallible way, on a non-infallible topic, a good Catholic must assent under pain of sin, possibly mortal. Canon 752 covers this case, (see below).
In brief, when the official Church teaches, we must assent. If we dissent, the gravity of the sin will depend on the gravity of the matter involved.
You will have to consult Fr. Hans Kueng to find out when the official Magisterium changed its teachings and on what matters. I know of none.
LET'S consider usury, a matter Kueng considers. The Church forbid its practice for several centuries on the grounds that inanimate things can't reproduce themselves. Money is inanimate, thus sterile. I doubt whether reigning pontiffs of the period ever issued any statements of any weight tantamount to an encyclical of today or even of a dogmatic declaration. However, they did teach no usury. For a Catholic of those days to accept usury would be a sin, a sin of disobedience, even though today's Catholic can accept usury, or interest on capital.
For centuries, Catholics couldn't eat meat on Friday. Today they can. When that prohibition was in force, the Magisterium was using its authority in a seriously binding way. One sinned seriously when one ate meat deliberately on Friday. Today, the Magisterium leaves the grave duty of mortifying oneself up to the individual, particularly how one will practice self-denial. The authority of the Church is involved in both instances, but differently.
A joke was going around a few years ago on what St. Peter was to do with those Catholics in hell because they ate meat on Friday. They are still there, I say, because they deliberately disobeyed the Magisterium.
Stupid Catholics there are. I recall one of them saying to me some time ago, "Well, if we can eat meat on Friday, we can get divorced and remarried." Sorry, these folks aren't working with a full deck.
In brief and in summary, when those who have been vested with divine authority teach in matters of faith and morals and discipline, a good Catholic obeys. He may not like it, he may detest it, but he assents, he obeys. He may have some question, like Mary herself at the Annunciation, but he obeys. There is no dissent, no disobedience, no waffling in the good Catholic.
Canon 752: While the assent of faith is not required, a religious submission of intellect and will is to be given to any doctrine which either the Supreme Pontiff or the college of Bishops, exercising their authentic declare upon a matter of faith or morals, even though they do not intend to proclaim that doctrine by definitive act. Christ's faithful are therefore to ensure that they avoid whatever does not accord with that doctrine.