What IS good, and how do we determine it?

[Metis]

The Orthodox and Catholic Church have both long held a traditio that Mary rose bodily into heaven at the end of her life; the main disagreement historically was if she was alive or dead when it happened. It was something that had always been around, all Pius (I thought it was XII?) did was say "we believe in this". They always did if you look back at Catholic art; most of the flying virgin pictures are from the 18th century long before the Dogma was pronounced. There's Byzantine icons of it long before them even still.

Yes, being a historian, I know that. But it goes to show that dogma is at least as much public acclamation as real theological argument. It changes with the lay of the land. Otherwise we wouldn't have a careful acceptance of evolution nowadays.

And Pius XII held the papacy between 1939 and 1958. It wasn't that late.

I just checked and the Dogma of the Assumption of Mary was formally proclaimed in Munificentissimus Deus on November 1st 1950. https://en.wikipedia.org/wiki/Assumption_of_Mary . Pius XII proclaimed it as a demonstration of Papal power, after WWII the Catholic Church was arguably at the strongest it had ever been since the glory days of Pius IX, hence why freethinkers like Paul Blanshard came out with books in the US during the 50's "warning" people about the increasing power the RC held over US society. The sexual revolution put an end to that of course.

I think you might be thinking about the Dogma of Papal Infallibility which was proclaimed during Vatican I which was led by Pius IX a few weeks before the destruction of the Papal States.

Also the Catholic Church hasn't accepted evolution, it abstains from having an opinion on the matter officially although I think John Paul 2 and Francis have both said they're for evolution. You'll find clergy all in good standing with Rome both for and against it.