So even if a previous Pope had agreed not to exercise his infallibility, this would not bind a future pope to that agreement? In that case, I don;t see how the Orthodox would accept any agreement of a pope not to exercise his infallibility. .
Popes are bound by dogma (whether the source is a council, a previous ex cathedra statement, or from the ordinary magisterium), but I don’t believe a pope would be bound by a disciplinary agreement.
Still,
Pastor Aeternus needn’t be the only statement providing conditions for a pope to speak infallibly. The church may have more dogmatically to say about the conditions and nature of ex cathedra statements. Though, of course, future clarifications could not contradict the solemn dogmatic assertions of
Pastor Aeternus
AFAIK, the Orthodox simply do not accept papal infallibility, which means that there will not be a reunion unless the RCC throws out this doctrine.
I must admit, things seemed much more possible 20 or 30 years ago. From the Catholic side, it seemed like (for better or for worse) there might be a willingness to tolerate being in communion with churches who did not fully accept all of the second order dogmata. Hence, the Ratzinger proposal and the Zoghby initiative.
In 1998, Pope John Paul II promulgated
Ad Tuendam Fidem, which adds to the Code of Canon Law and the Code of Canons of the Eastern Churches norms ‘which
expressly impose the obligation of upholding truths proposed in a definitive way by the
Magisterium of the Church, and which also establish related canonical sanctions.’
This includes an oath of fidelity from all clergy, eastern and western, to uphold not only first-order, divinely revealed truths, but also truths proposed as definitive by the magisterium and non-definitive, authentic teachings of the magisterium.
None of this touches the Orthodox directly, but Eastern Catholic Joseph Barstad’s article
Are the Ratzinger Proposal and Zoghby Initiative Dead? suggests that the Catholic Church has moved away from Ratzinger´s model of returning to a first-millennium style reunion.
I don’t object to any of this, as it seems to me absolutely appropriate that those in communion with Rome profess the doctrinal faith of Rome. But it does raise the bar to full communion (or, depending on how one reads the Ratzinger proposal, maybe the bar only
seems higher).
We can (and should) continue to work toward reunion and to hope for reunion. But the ecumenical landscape has changed.