Can approved theologians teach heresy? There is a sedevacantist blog that I have been reading lately. And the sedevacantist there posted that it was a lie that approved theologians can teach heresy. What do you think about this? Doesn't this take infallibility a little too far? Weren't there modernist theologians before Vatican II who were "approved" but were teaching heresy before Vatican II and didn't their teachings lead to Vatican II? Were all of their teachings safe until the moment that Pope Pius XII died and then suddenly they became heretical?

Approved by whom? Vatican II prelates?

Approved by the Church. Let's say up until Pope Pius XII died because the person who said it was a sedevacantist who does not recognize the Popes after him as true Popes. 

Anyone could be a heretic..... except a Pope.

Ok, but we also can't reduce what theologians teach down to individual opinions.

Better question- When theologians unanimously teaching something as revealed by God, are we bound by it?

What does the Papal Magisterium teach on THIS issue?

Ok, but we also can't reduce what theologians teach down to individual opinions.

Better question- When theologians unanimously teaching something as revealed by God, are we bound by it?

What does the Papal Magisterium teach on THIS issue?

"This Deposit of Faith our Divine Redeemer has given for authentic interpretation not to each of the faithful, not even to theologians, but only to the Teaching Authority [i.e., the Magisterium] of the Church."  --Pope Pius XII, Humani Generis, para 21.

The theologians must be governed by the Magisterium.  Too many traditional Catholics have it backwards and believe that everyone is governed by the theologians.  That is why we see so many "quote wars", quoting dueling theologians when the matters being discussed are either matters not yet definitively settled by the Church or ignoring what the Church has actually already declared because one's favorite quotes support what one wishes the teaching to be.

Ok, and we know the Magisterium teaches the fathers are infallible when unanimous or virtually unanimous.
Does the Magisterium teach whether the same unanimity of theologians is binding on the consciences of Catholics? I am not speaking of individual theologians, but when taken as a whole, are they infallible or at least safe?

No Gregory, it is incomplete therefore misleading to say that the fathers are infallible when unanimous or virtually unanimous - that is actually a half truth and as such is dangerous to the Church, therefore dangerous to our faith.

The First Vatican Council never taught that unanimity of the Fathers was even a criteria, let alone the only criteria necessary for infallibility. Nor did V1 teach that Ecuмenical Councils are infallible in and of themselves. While these ideas are wide spread, they are errors, errors which helped get us in this crisis in the first place.

Simply, "The Magisterium" is nothing other than the Church teaching us, that is what the Church does. The Church was established by Christ to teach us how to get to heaven. What "The Magisterium" is not, is the Church's hierarchy, nor is "The Magisterium" the saints, theologians, Fathers, Doctors, etc..

The Ordinary magisterium is the daily exercise on the part of the Church, of instructing and guiding us, telling us what we must believe, teaching us Catholic doctrine. This teaching is infallible only when it echoes or agrees with the Ordinary Universal Magisterium and/or the decrees of the Extraordinary Magisterium.

The Ordinary Universal Magisterium teachings are infallible, these are those teachings which Catholic theologians, with a "universal and constant consent", regard as being of the faith; as Pope Pius IX teaches in Tuas Libenter.

Here, it is important to understand what "universal" and what "constant" means.

"Universal" means "in time as well as space". It means those teachings which the Church has taught always and everywhere. "Universal" does not mean unanimity of the hierarchy or of the theologians or Doctors or the bishops in council or scattered throughout the world, etc..

"Constant" means "since the time of the Apostles".  

The Extraordinary Magisterium is when the Church, with an unusual gesture, such as through a Council or through an ex-cathedra statement teaches us. These Solemn teachings are infallible.  

We're bound no less by either the Ordinary, OUM or the Extraordinary Magisterium. No less because what we're bound by is Catholic truth, it does not matter the method, it is the matter, the truth that binds us.