Rest assured the formula change NEVER meant to imply that we believe in TWO divine principles
Jo, I believe and trust that the Roman Catholic Church does not believe in, teach or suggest two divine principles, which is one more reason why it should abandon the filioque.
Whereas the filioque is understandable and taught even by hesychastic fathers, in context of the Holy Trnity if not in those same words, it is not the truth purposefully expressed in the Symbol of Faith (the Creed), as finalized by the 4th Ecumenical Council; it does not so much teach error as it leaves room for it.
St. Symeon the New Theologian mentions that the Holy Spirit proceeds form the Father and through the Son. St. Gregory of Thessaloniki (aka Palamas) says that the Holy Spirit is a "kind of ineffable yet intense longing or eros experienced by the Begetter for the Logos born ineffably from Him, a longing experienced also by the beloved Logos and Son of the Father for His Begetter."
This is in perfect agreement with the Latin teaching that the Holy Spirit is the love experienced by the Father for the Son, and by the Son for the Father; that the Spirit is given to the Son by the Father and is His as much as it is the Father's.
"Yet," continues St. Gregory Palams, "the Spirit belongs also to the Son, Who receives Him from the Father as the Spirit of Truth, Wisdom and Logos."
Thus we are on the same plane here; we teach and believe the same thing here; theologically in this instance we do not profess two different faiths.
But, St. Gregory Palams makes sure that this is not confused with filioque, for the Creed must express the founding truth, the one that existed before all else existed: "Yet the Spirit has His existence from the Father alone, and hence He proceeds as regards His existence only from the Father." That truth is expressed in the Creed and it is the truth before all existence, that pertains solely to the Unbegotten God, the Intellect, the Wisdom, from Whom everything and all came to be, even the Holy Trinity.
I will leave it at that. I want to assure you that we are not on a collision course when it comes to the filioque. But I think it is now almost an agreed upon fact that filioque does not belong in the Creed.
Joe, allow me to recommend to you, as our brother Kosta already has, the writings of +Gregory Palamas especially on the Holy Spirit. It is my observation, and only that I might add, that Latin Church theologians seem to be moving in the direction of Palamite theology on the HS and away from the thoughts of Barlaam. At any rate, they are very much worth a read.