Endless rationalizations. The "Creed" is an exact definition of Faith, as formulated by the Councils. How can we profess the same Faith if the eastern half omits an important word, and the western part adds it?
I could understand that the uncertainty remains if the last Council were that of Ephesus, which the Latins reject. But the definition of the Faith as stated in that Council was approved and recognized, by the whole Church, as true and final at the the following Council. From then on, neither side of the Church had any authority to change its contents by adding or subtratcing from that expression of Faith lest it formulate a new faith -- because the finalized Creed is a definition of Faith, not a description of Faith.
That some individual Fathers of the East shared in formulating filioque before the Church defined it is not surprising. The Fathers were not always right on all points. But, the question is: did any of the Eastern Fathers continue to profess or speculate about the filioque after the Council of Chalcedon?
It appears that only the Western Patriarchate continued in its defiance of the Councils by insistitng on using the filioque.
Yes. For instance, St. Hormisdas' formula of reunion had the filioque. John of Montenero noted at Florence:
After Augustine came Pope Hormisdas, who reigned in the days of the Emperor Justin, when John, Patriarch of Constantinople, was trying to bring peace again to the Church after the aberrations of his predecessor Acacius. Both Emperor and Patriarch accepted the profession of faith of Hormisdas to make it the norm of orthodoxy. Yet that profession contained the following:'Great and incomprehensible is the mystery of the Trinity. God the Father, God the Son, God the Holy Ghost, an undivided Trinity, and yet it is known because it is characteristic of the Father to generate the Son, characteristic of the Son of God to be born of the Father equal to the Father, characteristic of the Spirit to proceed from Father and Son in one substance of deity' (P.L. 63, 514B).
But it is not an exhaustive definition. For instance, there is no definition Mary as the Theotokos, no definition of the Mass, no explanation of the nature of the Church as apostolic, etc.
St. Cyril, who was the driving force behind Ephesus, taught Filioque:
Since the Holy Spirit when He is in us effects our being conformed to God, and He actually proceeds from the Father and Son, it is abundantly clear that He is of the divine essence, in it in essence and proceeding from it.[D]id any of the Eastern Fathers continue to profess or speculate about the filioque after the Council of Chalcedon?
St. Maximus the Confessor approved of the teaching by Latin church.
The Fathers at the various councils were very careful in their wording. Show me one act of the entire Church before 1054 that explicitly condemned Filioque.
It appears that only the Western Patriarchate continued in its defiance of the Councils by insistitng on using the filioque.
You are not implying that the Western church was not the equal of the Eastern church, are you? Again, show me one canon from the councils explicitly forbidding the use of Filioque which the Western church defied.
All you can show me are private judgments that the Latin formulations are contrary to the faith.