Thus the Orthodox hesitate at a phrase like the pope’s “multiform fullness.” Catholic diversity makes it easy for Catholics to embrace us: When they look at us, they see the early church. We fit right in. But when the Orthodox look at Catholics, we see an extra thousand years of theological development, plus rebellion in the pews. What kind of unity do Catholics have, at present, that we could enter?

There are plenty of good reasons for the Orthodox and Roman Catholic churches to talk. Discussion clears away misunderstanding, and common causes can benefit from the energies of both churches. But we can’t be fully united until we agree on what “unity” means. ~Frederica Matthewes-Green,

I appreciate Mrs. Matthewes-Green’s comments on this question, and she conveys the very practical difference between the two conceptions of church unity that are often at work in disagreements between Orthodox and Catholics. For my part, I would have to say that I have no idea what might be meant by “multiform fullness,” which would sound to a great many Orthodox people as a vague endorsement of just about any form of Christianity. Proper ecclesial unity does not obliterate, but fulfills, particularities, but at the same time it reconciles them in Christ just as Christ reconciles all oppositions in Himself. Nonetheless, that unity presupposes adherence to a common faith, a common hierarchy and a common Eucharist. Most Orthodox people cannot imagine having the latter two without the first–this is the lack of what we would regard as substantive unity among Catholics that makes reunion especially daunting.

However, it would be unfair to good Catholic ecclesiology to reduce the Catholic conception of church unity entirely to an institutional model, as if Catholics were Catholics only on the basis of lines of authority and common membership distinct from communion based in homonoia or common-mindedness. Whether or not homonoia actually obtains among Catholics might be another question, but that better Catholic theologians see it as necessary for true ecclesiological unity is hard to deny. The institutional model is precisely the sort of model of the Catholic church that Pope Benedict XVI, according to what little I know of his predilections and views, apparently wishes to deemphasise. This is most welcome, since it is this institutional aspect that has for many centuries seemed one of the glaring consequences of the legalism and insistence on authority in the Roman church that seemed so alien to the spirit of Orthodoxy when Alexei Khomyakov was writing his delightful, short treatise The Church Is One. We would also miss something if we thought of unity-as-membership and unity-as-homonoia as genuinely different or opposed conceptions, since communion (sobornost in Russian or koinonia in Greek) implies and needs both and one cannot be a member of Christ without confessing the truth that He has revealed and which the Holy Spirit has confirmed in the teachings of the Church.

Hat tip to Orthodoxy Today.