Another important point in the Vatican document is the emphasis it lays on the distinction between ekporeusis and processio. It is historically true that in the Greek tradition a clear distinction was always made between ekporeuesthai and proeinai, the first of these two terms denoting exclusively the Spirit's derivation from the Father alone, whereas proienai was used to denote the Holy Spirit's dependence on the Son owing to the common substance or ousia which the Spirit in deriving from the Father alone as Person or hypostasis receives from the Son, too, as ousiwdws that is, with regard to the one ousia common to all three persons (Cyril of Alexandria, Maximus the Confessor et al). On the basis of this distinction one might argue that there is a kind of Filioque on the level of ousia, but not of hypostasis.However, as the document points out, the distinction between ekporeuesthai and proeinai was not made in Latin theology, which used the same term, procedere, to denote both realities. Is this enough to explain the insistence of the Latin tradition on the Filioque? Saint Maximus the Confessor seems to think so. For him the Filioque was not heretical because its intention was to denote not the ekporeuesthai but the proeinai of the Spirit.
This remains a valid point, although the subsequent history seems to have ignored it. The Vatican statement underlines this by referring to the fact that in the Roman Catholic Church today the Filioque is omitted whenever the Creed is used in its Greek original which contains the word ekporeuesthai.
(Sorry, I do not know how to include the Greek characters.)
This is only one point which the Metropolitan addresses. As you can see it is anything but cut and dry. I encourage to read the whole document. But for now I will ask again: If because of language difficulties we do not know exactly what the other is saying, is it not rash judgment to accuse one another of heresy?
So, in the western "jargon" the ousia is translated as substance? Am I to assume, then, that the substance in this case means the same as essence or nature?
Petrosius, I am being forced here to get into territory I had hoped I would not need to penetrate, disagreement among contemporary Eastern hierarchs. Do you wish union with the Church or simply union with those hierarchs who will either agree with you or with whom you can construct an agreed statement of some sort? If the former, you can only have it through repentance. If the latter, Metropolitan John just may be your guy.
At the Council of Florence, because of the force of circumstances and the Erastian policy of the Byzantine Emperor, all of the attendees who stayed to the end - with but one exception(St. Mark of Ephesus) - finally caved in and agreed to all of the Latin demands and union was proclaimed with bells and whistles. Is that your desire? Another Florentine union? If so, it has already been accomplished with some of the Eastern jurisdictions.
But what happened after Florence? All of the bishops who agreed to the Latin demands were defrocked and sent back to the monasteries to live out the rest of their lives in shame. The Ecumenical Patriarch died in Florence and was there buried. A few, such as Metropolitan Bessarion, were paid off with Latin jurisdictions or red hats.
My point is that everything you have brought up has already been covered ad infinitum by others far wiser than me. The best and the brightest hashed all of this out at Florence. And the best of them all was St. Mark of Ephesus. Instead of beating your brains out against poor little old me, read the History of the Council of Florence by Ivan Ostroumoff. Then, and only then, if you still think you have something to say, say it.