Much of the East's issue with the filioque has to do with proceedure. They see Rome as having unilaterally amending the Nicene Creed by fiat.
Secondly, the Nicene Creed defines God as God the Father: "I believe in one God, the Father Almighty..." The Creed then goes on to define the Son as "eternally begotten of the Father" and the Holy Ghost as "proceeding from the Father". In Eastern theology, "God" means "God the Father". From God is begotten the Son and from God proceeds the Holy Ghost. With that line of reasoning, the Holy Ghost cannot proceed from the Son for the same reason the Son is not eternally begotten of the Holy Ghost. Western theology defines God as God the Trinity. With the implications thereof, the double procession of the Ghost is a must. Eastern Orthodox theologians consider this valid line of reasoning (Augustine of Hippo is considered an Orthodox saint), however it would require a complete rewriting of the Nicene Creed (which was writen in accordance with Eastern theological methods). Given that that great creed came about only after the Emperor locked the bishops in a palace and wouldn't let them out until they solved their differences, I don't see a complete rewrite of the Creed as happening before pigs learn to fly.
It may be best for Western theologians to accept that the Nicene Creed is an inappropriate place to express Augustinian Trinitarianism. Eastern theologians could then compromise by accepting that the Julian Calendar is in error at a rate of 3 days every 400 years and start applying the Nicene formula for setting Pascha to the Gregorian Calendar.
Sigh. Actually this is untrue.
It is our belief that the filioque is "theologically inexact and spiritually harmful", to quote Ware.
All things come from the Father.
I was told by Kolokotronis that Augustine did not understand Trinity because he did not know Greek. He did not provide any criticism of Augustine's reasoning beyond that he did not refer to any Greek words. I am hoping to get more from Kolokotronis today.
Where are the Eastern theological methods apparent in the Greed? I ask because I don't know.
And would not the West be perfectly justified, under the same doctrine, in viewing the 381 Creed as "unilaterally amending the Nicene Creed by fiat"? Ephesus made no mention of the 381 Creed in its prohibition against creating a creed other than that set forth at Nicaea (not Constantinople), and there are compelling arguments that the council of the 150 Fathers (which didn't even bother trying to invite Westerners) was not recognized as Oecumenical until after Chalcedon. What's worse, there's also a real possibility that the 381 Creed was never approved by the Council at all, which would place its first approval at Chalcedon - after Ephesus laid down its canon against change to the Nicene Creed. When the Creed was read at Ephesus, it was the real Nicene Creed, not the 381 Creed which is improperly called the "Nicene Creed". The case against the 381 Creed is far more powerful then the case which the Greeks made against the Latin Creed - it's no surprise that at Florence the Greeks were forced to admit defeat.
Should the Latin line of reasoning, in view of the interpenetration of the Persons, be that the Son is doubly begotten by the Father and the Holy Ghost? It is my pet heresy.
Please see Dionysius' post above this, quoting you.