That does not agree with the patristic saying that faith is once delivered and believed everywhere and always.
There is a difference between understanding and faith. One does not necessarily negate, reduce or expand the other.
that does not necessarily invalidate that understanding
It doesn't validate it either. Christianity went from being a Jewish sectarian religion to being an amalgam of a specific flavor of Judaism, Greek Pagan philosophy (Plaotnism, Stoicism, etc.), and Persian (Zoroastrian) dualism. We can say that Christianity gradually (and consensually) evolved, especially in the West, without necessairly being either valid or invalid.
If the argument is that greater understanding lessens the validity of the faith, then I would differ with that. I think that the odds are that greater understanding can lead to greater faith, but not in all instances.
It is possible that we simply understand God better (not completely, of course not, but better than the fishermen and salesmen 2000 years ago).
It's possible, but doesn't seem probable.
Does the Nicene Council give evidence of greater understanding than Irenaeus, for instance? Do the Ecumenical Councils throughout the first millennium give ever increasing understanding? I submit that they do.
As for human understanding of God, how can finite even begin to encompass the infinite? Why, if God is infinite, then the combined understanding of all humanity that ever lived, lives and will live amounts to nothing compared to what God truly is.
The mathematical opposite of infinity is 1/x as x goes to infinity. However, since we have had revelation of God, we are not at the opposite of infinity. If we can increase our understanding, then it is not for naught - it is something.
What greater 'understanding', Mark? The Church claims the Apostolic faith. Does the Church 'understand' the faith better or to a greater extent than the Apostles did? Mark, the faith was passed on from the Apostles to the bishops, as catholic, once delivered, believed everywhere and always.
However, since we have had revelation of God, we are not at the opposite of infinity. If we can increase our understanding, then it is not for naught - it is something.
Mark, a revelation is simply discovery (to reveal, uncover) that something exists, not an in depth understanding what it is. Our 'understanding' of God is exactly the same as it was when the faith was delivered, or so the Church will tell you. It's an oxymoron.