Thak you, excellent question. We don't always know. It took the Church several centuries to decide which of the writings of the early Church were inspired and which were not. Before that -- that is before the councils of Orange and Rome in late 4-early 5 c. much of what you now know as Holy Scripture was simply tradition. Of some gospel and epistles there was little doubt, of others, the debate continues even after canonization (which was done in a local council anyway). Further, the Church never said that the books that were not canonized were without merit. They formed what we call patristic literature, binding on a Catohlic Christian where it reveals a consensus of the fathers, but not necessarily in every detail.
On the subject on hand, there is a common belief in the Early Church that Our Lady remained virgin. That is consistent with what the scripture reveals of her, consistent with any other teaching of the Church and is of historical early origin. So that is a part of the Holy Tradition.
And that is the general rule: a traditional belief may or may not be a part of the Holy Tradition. If it is historically extending from the Early Church, and consistent with the rest of the Christian teaching, including the canonized scripture, then it is Holy Tradition. Otherwise it is perhaps of some value but it is not binding on us.
At times someone comes up with a thought or a revelation that he personally experienced and he insists that he discovered a truth. If he can trace it to the Fathers of the Church and if it is consistent with the rest of the Christian faith, that becomes something that other Catholics may join in believing. If t becomes a significant development in the faith the Church may make an official pronouncement allowing that private revelation as a private choice of veneration. Examples of that are all canonizations of saints, the Apparition of Fatima, the writings of people like St. Thomas Aquinas, etc. They becomes something the Church recommends as a choice to listen to or venerate. They are not binding but they are approved. They do not become Holy Tradition because they ar ento of apostolic origin, but they add to the magisterial teaching.
Next, there are thoughts and revelations that are not approved. Numerous miracles and revelations are in this category, and massive Christian literature of which the Church has not made any determination. The various types of journalism fodder, like when some prelate says that he believes in space aliens. A well known one like that is the miracles at Medjugorie.
Lastly, there are thoughts and revelations that ther Church definitively ruled against. Such are theories that run contrary to the Scripture and therefore on that criterion alone are harmful to a Christian believer. The teachings of Luther, Calvin and the rest of the mental garbage that came out of the Reformation are in that latter category.
Thak you, excellent question. We don't always know
You got that right.
RCs can rationalize all they want, but the bottom line is that so many of their beliefs and practices contradict the word of God, as they have done for centuries.
Argument over. Rome loses.
So in other words the men that developed the tradition decide if it is from men or God?