What a long time ago it seems ... when our beloved Pope Emeritus began to write about Liturgy. Do you remember the reaction which followed? It was as if a gang of yobs had broken into a meeting of deeply religious and proper Maiden Aunts, and had started shouting very naughty words. The pursed lips ... the frozen atmosphere of disapproval ... that was how the liturgical establishment responded. "But he's not a liturgist!!!" they cried, if ever they ventured to unpurse their frigid lips. They meant that he was not one of them; had attended none of their conventions; had written no little articles in their house journals; had rampaged through no diocese laying waste the sanctuaries; had hurled no reliquaries, no baroque vestments, upon bonfires; had destroyed no traditions of sacred chant.
And I'm sure you have The Spirit of the Liturgy upon your bookshelves. Have you recently reread the chapter on images? The Cardinal Prefect writes: "The Church of the West ... must achieve a real reception of the Seventh Ecumenical Council, Nicaea II, which affirmed the fundamental importance and theological status of the image in the Church." Indeed, in the decades after the iconoclasm which, totally without mandate, followed Vatican II, it was Nicaea II, not Vatican II, which should have been the bedside reading of bishops and of diocesan directors of Liturgy.
But that chapter has something even more remarkable in it. "The Western Church does not need to subject herself to all of the individual norms concerning images that were developed at the councils and synods of the East, coming to some kind of conclusion in 1551 at the Council of Moskow, the Council of the Hundred Canons. Nevertheless, she should regard the fundamental lines of this theology of the image in the Church as normative for her". Can you think of another example of a Roman Pontiff holding up for acceptance "as normative" the "fundamental lines" of conciliar doctrinal developments within 'post-schism' [I use Robert Taft's term] Orthodoxy? Calling his fellow Latins to go to school in Byzantium? If you want an ecumenism which is one, not of Gesture but of Substance, Ratzinger is your man.
Taking this approach further, I have found myself wondering whether Latin Catholics should discern, in the Synod of Bethlehem, authoritative teaching preserved in unbroken traditions of Separated Particular Churches; and ... I am aware that I am sticking my neck out here ... whether the "fundamental lines" of the teaching on Theosis by the 'Palamite' councils of the fourteenth century, elucidating the the doctrine of S Athanasius, of the Cappadocians, of S Symeon the New Theologian, of S Gregory Palamas himself, deserve to be taken seriously in the West. (It is good to see Palamas' name on the calendars of Particular Churches which are in peace and communion with the See of S Peter. Does S Thomas Aquinas appear in any Orthodox Calendars?)