The Magisterium teaches infallibly in any of three ways and in only those three ways:
1. Papal Infallibility,
2. Conciliar Infallibility
3. the ordinary and universal Magisterium (universal Magisterium for short)
Papal Infallibility requires the teaching to meet all the conditions prescribed by Vatican I and reiterated by Vatican II. Otherwise, the teaching of the Roman Pontiff on matters of faith, morals, and salvation is non-infallible and subject to a limited possibility of non-grave error and of reform.
Conciliar Infallibility requires an Ecumenical Council whose decisions on doctrine are approved by the Roman Pontiff. Any documents or decisions of a Council not approved by the Pope are not of the Council. An Ecumenical Council, by definition, is a gathering of the body of Bishops (or a subset of Bishops who represent the body) with the Roman Pontiff. But the Pontiff may be present by means of a legate, or he may be figuratively present by the communion of the body with its head and by his later approval of the Council’s acts.
In theory, the Roman Pontiff could gather with the body of Bishops figuratively, by means of communication, and then issue an infallible definition of doctrine.
The Universal Magisterium occurs when the body of Bishops dispersed in the world and the Roman Pontiff teach the same position, definitively to be held, but without one particular definition issued by the body with its head. Instead, a series of non-infallible teachings with the same position, including by many Bishops throughout the world and the Pope or successive Popes, becomes infallible when all are in agreement.
Local gatherings of Bishops and individual Bishops cannot teach infallibly.
A Bishops’ Conference is essentially an on-going local gathering of Bishops, e.g. a local council or local synod. Such local gatherings have been in practice in the Church since the beginning. But the authority of such a local group of Bishops is no different from that of a Bishops’ Conference. They cannot teach infallibly because they are not the body of Bishops and they do not have the Roman Pontiff as the head of the local group. Even when the Conference is in full communion with the Roman Pontiff, he is not the head of the Conference, as proven by the election in each Conference of a local Bishop to lead them.
Infallibility requires the Roman Pontiff alone or the Pope and the body of Bishops. A Bishops Conference has neither, so they cannot teach infallibly. They can err to any extent. The Pope individually, and the body of Bishops as a body only, cannot err gravely in discipline or doctrine. But an individual Bishops or local group of Bishops can err gravely, as proven by the Schism of 1054. Since a Bishops Conference is not fundamentally different from a local group of Bishops, they can err gravely.
What if the Roman Pontiff approves of the decision on doctrine or discipline of a Bishops’ Conference? Unless the Pope issues his own decision infallibly, via Papal Infallibility or the issuance of a dogmatic fact, the Council’s decisions can err.
Can they err gravely if the Pope approves? Sometimes the Pope approves of a document through a Vatican congregation, in which case a grave error can perhaps occur. I think so because a teaching is not infallible if it is issued by, for example, the Congregation for the Doctrine of the Faith, even if the Pope approves. For Papal Infallibility to occur, the teaching must be directly from the Pope. So a Bishops’ Conference’s decision cannot be infallible, not even if the Pope approves and it meets the other conditions for infallibility. For it was not issued by the Roman Pontiff, therefore, in the document, the Pope is not speaking ex cathedra, but the Bishops are speaking from their respective chairs as the successors of the other Apostles.
Grave error might be possible in a document merely approved by the Pope, and not issued from the Pope as from Peter’s chair. For a Pope might misunderstand what the Bishops intended, especially when differences in language and local expressions may obscure a meaning. But a Pope does not misunderstand what he himself states.
So the protection which Vatican I teaches is divinely-conferred on Peter and his successors in his chair does not extend to any document approved by the Pope, but only to those from the Pope per se, or from a Council, or from the ordinary and universal Magisterium.
Even so, it is reprehensible and highly offensive to Christ for individual Catholics, including priests, deacons, theologians and various types of lay leaders to rebel against and openly condemn the decision of a Bishops’ Conference approved by the Roman Pontiff. For such decisions on discipline and doctrine are of the authority of Christ. Individual Bishops and local groups of Bishops exercise the teaching and temporal authority of Christ when they remain in communion with the body of Bishops and the Roman Pontiff. The mere possibility of grave error is not sufficient for individual Catholics and self-organizing groups of Catholics (not approved by the Church) to exalt themselves above the Bishops, to judge and condemn them for teaching contrary to one’s own understanding. This is not humility, but pride. This is not faith, but the reason of fallen sinners. This is not the work of the Holy Spirit, but the spirit of secular culture, a culture which teaches individuals to put themselves above their leaders and to treat their leaders with contempt.
Do not be quick to judge that a Bishop or a Bishops’ Conference has erred gravely, especially when the Holy See has approved.
On the Other Hand
Alternately, when the Holy See or the Roman Pontiff has rejected a decision of a local Conference, stand with the successor of Peter, so as to stand with Christ.
Warnings from the Blessed Virgin Mary
In the messages to Pedro Regis (a true private revelation), Mary warns us repeatedly that the enemies of the Church will lead many astray, and that we must remain faithful to the Roman Pontiff and the true Magisterium. Regardless of whether the Pope is conservative or liberal or whatever else, he is the Vicar of Christ.
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