This is indeed an interesting difference between Catholics and Orthodox. What puzzles me is that when looking for an answer, the Orthodox believe all they can do is look back on previous teachings by the Church Fathers or by doctrines defined at Ecumenical Councils.
Actually, it really comes down to our differences on the matter of "development of doctrine". We believe that our doctrine cannot
be "developed" and must be one with the Church of the past, and thus must be judged on the basis of the doctrine of the Church of the past. All that the Church has authority to do is define, formulate, and clarify the doctrine of the Apostles; it has no authority to in any way edit it. This does not mean that we no longer have teaching authority: we certainly do still have authority to define, formulate, and clarify the Apostolic doctrine. This is why we look back to the Church of the past, because our doctrine today must be one with it and we must be judged by their doctrine.
There is a quote I heard from a theologically conservative Episcopalian professor at the local seminary in Berkeley: "I do not judge the Creed, but rather the Creed judges me." Of course, he was meaning something rather different by it; that the revisionist trend in the Episcopal church to pick and choose what we feel is reasonable amongst the parts of the Creed is erroneous. However, I think it points to this reality, however. We hesitate to view ourselves as judges of the Tradition of the Church past, as this runs the risk of the revisionism you see in your own tradition. Rather we first look to conform ourselves to former doctrinal formulations, for the safe sake of being one in doctrinal substance.
I do not think that this approach is really different from that of the Fathers. Yes, it is true that they did significantly more formulating than we have since then. But there is certainly a reason for this. They did not yet have the formulaic structure to fall back on like we do today. When faced with heresies, they were forced to extricate formulas from the substantial doctrine of the Church that they knew. Heresies over time have become more and more recycled. As time passes on, we have more and more of a formulaic basis to fall on to fight heresies rather than trying to introduce new formulas. So the Fathers did more formulating because they had to. But I do not think that they had a distinct perspective from us about "doctrinal development". I think they very well recognized that the Church only had authority to define, refine, formulate, and clarify doctrine, not to edit it in any way. I think that they saw their formulas as either particular rephrasings of doctrine that had already been presented to the Apostles. And I think they came up with these formulas looking highly to those who had come before them, knowing that their formulations had to be judged by the doctrine of their predecessors. For instance, it is quite clear that Saint Cyril of Alexandria did not view his formulation of the hypostatic union as some new doctrine or a "doctrinal development", but rather simply the proper phrasing and implication of the doctrine of his revered Father Saint Athanasius who taught that the Lord Christ is one in substance with the Father; how else could that be possible without the hypostatic union?
On the other hand, we most certainly see that you believe you have the authority to develop doctrine and that you have authority in and of yourselves to define doctrine in a way we do not see ourselves as having. The filioque
is a great example. What had been the apparent reality to us since Apostolic times is that the Holy Spirit is ontologically spirated particularly from the Father and that the Father alone is the fountainhead or source in the Godhead. Your church came along and began to say that the Son ontologically spirates the Holy Spirit along with the Father. You would say, via the infallibility of the Pope, that you had the authority to define this doctrine. We, on the other hand, judged this doctrine on the basis of what we say preceding it and found it contradictory to the Apostolic doctrine.
So no, it is not a matter of us thinking that Church authority terminated at some point, but rather that, in a lack of confidence in our individual teachings, that our doctrine must be judged on the basis of that which in the Church past is known to have been authoritative.