Filioque

Filioque, a Latin term meaning "and from the Son", was added to the original Nicene Creed, and has been the subject of great controversy between Eastern and Western Christianity. The term refers to the Son, Jesus Christ, with the Father, as the one shared origin of the Holy Spirit. It is not in the original text of the Creed, attributed to the First Council of Constantinople, which says that the Holy Spirit proceeds "from the Father" without the addition "and the Son".
In the late 6th century, some Latin Churches added the words "and from the Son" to the description of the procession of the Holy Spirit, in what many Eastern Orthodox Christians have at a later stage argued is a violation of Canon VII of the Council of Ephesus, since the words were not included in the text by either the First Council of Nicaea or that of Constantinople. The inclusion was incorporated into the liturgical practice of Rome in 1014, but was rejected by Eastern Christianity.
Whether that term Filioque is included, as well as how it is translated and understood, can have major implications for how one understands the doctrine of the Trinity, which is central to the majority of Christian churches. For some, the term implies a serious underestimation of God the Father's role in the Trinity; for others, its denial implies a serious underestimation of the role of God the Son in the Trinity.
The term has been an ongoing source of difference between Eastern Christianity and Western Christianity, formally divided since the East–West Schism of 1054. There have been attempts at resolving the conflict. Among the earlier works that have been used in support of the compatibility of Filioque with Orthodox dogmatic teachings are the works of Maximus the Confessor in early 7th century, canonized independently by both Eastern and Western churches. Differences over this and other doctrines, and mainly the question of the disputed papal primacy, have been and remain the primary causes of the schism between the Eastern Orthodox and Western churches.

Nicene Creed

The Nicene Creed as amended by the Second Ecumenical Council held in Constantinople in 381 includes the section:

Greek original	Latin translation	English translation
Καὶ εἰς τὸ Πνεῦμα τὸ Ἅγιον, τὸ Κύριον, τὸ ζῳοποιόν	Et in Spiritum Sanctum, Dominum et vivificantem,	And in the Holy Spirit, the Lord, the giver of life,
τὸ ἐκ τοῦ Πατρὸς ἐκπορευόμενον,	qui ex Patre procedit,	who proceeds from the Father,
τὸ σὺν Πατρὶ καὶ Υἱῷ συμπροσκυνούμενον καὶ συνδοξαζόμενον,	qui cum Patre, et Filio simul adoratur, et cum glorificatur,	who with the Father and the Son is adored and glorified,

The controversy arises from the insertion of the word Filioque in the line:

Greek	Latin	English translation
τὸ ἐκ τοῦ Πατρὸς	qui ex Patre	who proceeds from the Father ,

Controversy

The controversy referring to the term Filioque involves four separate disagreements:

Controversy about the term itself
Controversy about the orthodoxy of the doctrine of the procession of the Holy Spirit from the Father and the Son, to which the term refers
Controversy about the legitimacy of inserting the term into the Niceno-Constantinopolitan Creed
Controversy about the authority of the Pope to define the orthodoxy of the doctrine or to insert the term into the Niceno-Constantinopolitan Creed.

Although the disagreement about the doctrine preceded the disagreement about the insertion into the Creed, the two disagreements became linked to the third when the pope approved insertion of the term into the Niceno-Constantinopolitan Creed, in the 11th century. Anthony Siecienski writes that "Ultimately what was at stake was not only God's trinitarian nature, but also the nature of the Church, its teaching authority and the distribution of power among its leaders."
Hubert Cunliffe-Jones identifies two opposing Eastern Orthodox opinions about the Filioque, a "liberal" view and a "rigorist" view. The "liberal" view sees the controversy as being largely a matter of mutual miscommunication and misunderstanding. In this view, both East and West are at fault for failing to allow for a "plurality of theologies". Each side went astray in considering its theological framework as the only one that was doctrinally valid and applicable. Thus, neither side would accept that the dispute was not so much about conflicting dogmas as it was about different theologoumena or theological perspectives. While all Christians must be in agreement on questions of dogma, there is room for diversity in theological approaches.
This view is vehemently opposed by those in Eastern Orthodox Church whom Cunliffe-Jones identifies as holding a "rigorist" view. According to the standard Eastern Orthodox position, as pronounced by Photius, Mark of Ephesus and 20th century Eastern Orthodox theologians such as Vladimir Lossky, the Filioque question hinges on fundamental issues of dogma and cannot be dismissed as simply one of different theologoumena. Many in the "rigorist" camp consider the Filioque to have resulted in the role of the Holy Spirit being underestimated by the Western Church and thus leading to serious doctrinal error.
In a similar vein, Siecienski comments that, although it was common in the 20th century to view the Filioque as just another weapon in the power struggle between Rome and Constantinople and although this was occasionally the case, for many involved in the dispute, the theological issues outweighed by far the ecclesiological concerns. According to Siecienski, the deeper question was perhaps whether Eastern and Western Christianity had wound up developing "differing and ultimately incompatible teachings about the nature of God". Moreover, Siecienski asserts that the question of whether the teachings of East and West were truly incompatible became almost secondary to the fact that, starting around the 8th or 9th century, Christians on both sides of the dispute began to believe that the differences were irreconcilable.
From the view of the West, the Eastern rejection of the Filioque denied the consubstantiality of the Father and the Son and was thus a form of crypto-Arianism. In the East, the interpolation of the Filioque seemed to many to be an indication that the West was teaching a "substantially different faith". Siecienski asserts that, as much as power and authority were central issues in the debate, the strength of emotion rising even to the level of hatred can be ascribed to a belief that the other side had "destroyed the purity of the faith and refused to accept the clear teachings of the fathers on the Spirit's procession".

History

New Testament

It is argued that in the relations between the persons of the Trinity, one person cannot "take" or "receive" anything from either of the others except by way of procession. Biblical texts such as John 20:22 were seen by Fathers of the Church, especially Athanasius of Alexandria, Cyril of Alexandria and Epiphanius of Salamis, as grounds for saying that the Spirit "proceeds substantially from both" the Father and the Son. Other texts that have been used include Galatians 4:6, Romans 8:9, Philippians 1:19, where the Holy Spirit is called "the Spirit of the Son", "the Spirit of Christ", "the Spirit of Jesus Christ", texts in the Gospel of John on the sending of the Holy Spirit by Jesus, and John 16:7. Revelation 22:1 states that the river of the Water of Life in Heaven is "flowing from the throne of God and of the Lamb", which may be interpreted as the Holy Spirit proceeding from both the Father and the Son. Tension can be seen in comparing these two passages:

John 14:26 NASB – "But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you."
John 15:26 NASB – "When the Helper comes, whom I will send to you from the Father, the Spirit of truth who proceeds from the Father, He will testify about Me"

Siecienski asserts that "the New Testament does not explicitly address the procession of the Holy Spirit as later theology would understand the doctrine", although there are "certain principles established in the New Testament that shaped later Trinitarian theology, and particular texts that both Latins and Greeks exploited to support their respective positions vis-à-vis the Filioque". In contrast, Veli-Matti Kärkkäinen says that Eastern Orthodox believe that the absence of an explicit mention of the double procession of the Holy Spirit is a strong indication that the Filioque is a theologically erroneous doctrine.

Church Fathers

Cappadocian Fathers

wrote: "Through the one Son is joined to the Father". He also said that the "natural goodness, inherent holiness, and royal dignity reaches from the Father through the only-begotten to the Spirit". However, Siecienski comments that "there are passages in Basil that are certainly capable of being read as advocating something like the Filioque, but to do so would be to misunderstand the inherently soteriological thrust of his work".
Gregory of Nazianzus distinguished the coming forth of the Spirit from the Father from that of the Son from the Father by saying that the latter is by generation, but that of the Spirit by procession, a matter on which there is no dispute between East and West, as shown also by the Latin Father Augustine of Hippo, who wrote that although biblical exegetes had not adequately discussed the individuality of the Holy Spirit:
Gregory of Nyssa stated:

Alexandrian Fathers

provides "a host of quotations that seemingly speak of the Spirit's 'procession' from both the Father and the Son". In these passages he uses the Greek verbs προϊέναι and προχεῖσθαι, not the verb ἐκπορεύεσθαι, the verb that appears in the Greek text of the Nicene Creed.
Epiphanius of Salamis is stated by Bulgakov to present in his writings "a whole series of expressions to the effect that the Holy Spirit is from the Father and the Son, out of the Father and the Son, from the Father and out of the Son, from Both, from one and the same essence as the Father and the Son, and so on". Bulgakov concludes: "The patristic teaching of the fourth century lacks that exclusivity which came to characterize Orthodox theology after Photius under the influence of repulsion from the Filioque doctrine. Although we do not here find the pure Filioque that Catholic theologians find, we also do not find that opposition to the Filioque that became something of an Orthodox or, rather, anti-Catholic dogma."
Regarding the Greek Fathers, whether Cappadocian or Alexandrian, there is, according to Siecienski, no citable basis for the claim historically made by both sides, that they explicitly either supported or denied the later theologies concerning the procession of the Spirit from the Son. However, they did enunciate important principles later invoked in support of one theology or the other. These included the insistence on the unique hypostatic properties of each Divine Person, in particular the Father's property of being, within the Trinity, the one cause, while they also recognized that the Persons, though distinct, cannot be separated, and that not only the sending of the Spirit to creatures but also the Spirit's eternal flowing forth from the Father within the Trinity is "through the Son".