Agrarian, you have certainly answered Stripes' question much more inclusively than I have, and that is good. It shows that in addition to theology and ecclasiology, it is ultimately the praxis, the life in the Church is ultimately the all-encompassing concept of what is known as the "Orthodox Church," and that, looking at the Big Picture, that Church is very, very different from the (Latin) Catholic Church as we know it.
I am not sure – given the virtual apartheid that existed linguistically and in day-to-day life of the Greek and Latin Churches since the 5th century A.D. – that a Greek would have recognized the same Faith in Rome or Spain even in the first millennium, let alone understand the language of the Liturgy, yet the Churches were in full communion.
You see, communion is not a means of achieving unity but an expression of it. That's why we cannot allow our Catholic brethren to partake of it in Orthodox Churches. Not yet anyway. Being in communion simply means that, regardless of the praxis, our bishops hold that those bishops with whom they are in communion teach the same Faith and confomr to the same canon.
However, there were periods, lasting even decades, in the history of the Church in the first millennium when the East and the West were not in communion for reasons that were not theological, as is the case with the current issue of the so-called Macedonian and Montenegrin "churches." Oh, for sure, theologically, they are Orthodox, but they have claimed autocephaly in a way that is not prescribed by the canon.
If a bishop finds another bishop to teach that which he believes is wrong, the bishop will ex-communicate the other bishop until such issue is resolved.
The term excommunication has acquired loaded meanings as you noted in one of your earlier posts, but it only means that one bishop believes the other either teaches or does something that is theologically or ecclesiastically wrong.
But that does not excommunicate the bishops from the entire Church. I am sure that St. Augustine and St. John Cassian were not in communion. Yet, both are saints in the Orthodox and Roman Catholic Churches. Moreover, John Cassian was condemned for his semipelagianism by the Local (Latin) Council of Orange, as was most of the teaching of St. Augustine by the Orthodox Church in the 15th c. and neither were "stripped" of their sainthood by either Church.
It is only when the entire Church Community backs one bishops that the other bishop can be considered outside the Church, which is the case between the East and the West at this point, although the event of 1054, as I mentioned earlier did neither imply, nor aim at such exclusion because the excommunicatios issued were (1) legally invalid and (2) directed at specific bishops and not the entire Greek or Latin community.
In the period of the undivided Church, such disagreements were addressed by Ecumenical Councils and resolved. Obviously such a council was convened even in the informally divided Church, in Florence, but failed on the local level (the Orthodox laity and lower clergy rejected it).
The real Great Schism that widened the gap between the two Churches occurred not in 1054 but in 1870 (Vatican I), when the ex-cathedra infallibility of the Bishop of Rome was added (and eventually dogmatized) to the original topics dealing with liberalism, relativism, modernism and lack of piety for the Eucharist.
If we profess the same faith, outward differences in our approach to praxis should not be a justification to exclude a member of the other community Eucharistically. Outward expressions of our faith, the praxis, the manner of worship, etc. cannot be insisted on as long as they do not violate the Holy Tradition, i.e. do not clash with Apostolic teachings, the Scripture and the pronouncements of the Ecumenical Councils.
"I am not sure – given the virtual apartheid that existed linguistically and in day-to-day life of the Greek and Latin Churches since the 5th century A.D. – that a Greek would have recognized the same Faith in Rome or Spain even in the first millennium, let alone understand the language of the Liturgy, yet the Churches were in full communion."
I believe quite the opposite -- that they *would* have recognized the same faith. There is no way to prove either proposition, I would suppose.
Think of St. John Cassian, who moved back and forth between East and West -- he obviously recognized the same faith in Egypt and the Holy Land, and when his writings about what he experienced there returned to the West, they inspired and influenced Western monasticism. Think, even, of the fact that at Charlemagne's coronation, the Pope celebrated a Liturgy of St. John Chrysostom.
The world of the first half of the first millenium was a rather cosmopolitan one, and I would argue that the world of the second half of the first millenium was far more cosmopolitan than is commonly assumed -- both in the east and the west.
The linguistic "apartheid", as you call it, contributed to the schism in that it delayed the East's awareness of the rising strain in the West that ended up dominating Catholicism after the political takeover by the Franks.
I know that when I visit pre-schismatic church buildings, listen to pre-schismatic western chant, read pre-schismatic western patristic writings, read pre-schismatic western liturgical texts, etc..., it seems *very* familiar to me.
But that is just an opinion. It may be that all that kept the bishops in communion with each other were agreement on dogmatic declarations of faith. I think it was more than that, but again, this is difficult to prove.
"The real Great Schism that widened the gap between the two Churches occurred not in 1054 but in 1870 (Vatican I), when the ex-cathedra infallibility of the Bishop of Rome was added (and eventually dogmatized)..."
I would agree completely that it is the dogmatic declaration of infallibility that seems to be the major obstacle at this time. The filioque is still a major dogmatic theological issue, at the heart of things is are core differences in how we look at grace, original sin, etc... -- but I'm not sure to what extent the later Roman teachings are considered to be dogmatized (although they will *all* have to be dogmatized for a union to take place -- they are issues, and would need to be resolved in Council.)
But I simply do not understand how, given the fact that Orthodox Christians willfully, in full knowledge, reject that conciliarly-declared dogma of the Catholic Church, we could be invited to partake of communion in Catholic Churches. How can one be considered to be of the same faith when one specifically rejects a dogma?
Calling Vatican I a local council doesn't help -- are we to say that the Pope is infallible in the West, but not in the East? He loses his infallibility when he crosses into the territory of the Patriarch of Serbia, or any doctrinal statements he makes in writing are infallible in Rome, but not in Constantinople?