East and West can easily continue dialogue also as regards the Filioque question providing there is full acceptance of the doctrine of tradition on the monarchia of the Father. The monarchia of the Father means that the Father is the sole origin and cause both of the Son and of the Spirit.
This is a very valuable statement on the thorny issue of the Filioque, which clarifies many aspects of the position of the Roman Catholic theology on this matter. I am sure that this statement will play a very important role in the official theological dialogue between the Roman Catholic and the Orthodox Church when it comes to the point of discussing this issue. My reaction as an Orthodox theologian to this document can be summarized in the following observations:
1. It is with deep satisfaction that I read in the document the emphatic assertion that no confession of faith belonging to a particular liturgical tradition can contradict the expression of faith of the Second Ecumenical Council (Constantinople 381) which has been taught and professed by the undivided Church. This is a very good basis for discussion.
2. It is extremely important, in my judgment, to clarify the point concerning the “source” (????) or “principle” (?????) or “cause” (?????) in the Holy Trinity. This is crucial perhaps decisive. The document of the Vatican sees no difference between the monarchia of the Father, i.e. the idea that the Father is the sole “principle” in God’s Trinitarian being, an idea strongly promoted by the Greek Fathers, and St. Augustine’s expression that the Holy Spirit proceeds from the Father “principaliter”. However, before we can come to the conclusion that the two traditions, Eastern and Western, understand this matter in the same way, we must raise the following questions:
a) Does the expression “principaliter” necessarily preclude making the Son a kind of secondary cause in the ontological emergence of the Spirit? The Filioque seems to suggest two sources of the Spirit’s personal existence, one of which (the Father) may be called the first and original cause (principaliter), while the other one (the Son) may be regarded as a secondary (not principaliter) cause, but still a “cause” albeit not “principaliter”.
The discussions both at the time of St. Photius and at Lyons and Florence-Ferrara seem to have paid special attention to this delicate point. It is not accidental that the Greek theologians ever since the time of Photius insisted on the expression:???? ?????? ? ?????? i.e. the Father is the sole cause of the Son as well as of the Spirit. This concern does not seem to be fully covered by the Augustinian expression principaliter. The second Council of Lyons is unclear on this matter when it says that the Father as Father of His Son is "together with Him the single principle from which the Spirit proceeds". b) In the light of this observation it would be important to evaluate the use of the idea of cause (?????) in Trinitarian theology. It was not without reason that the Cappadocian Fathers introduced this term next to the words ???? and ????? (source and principle) which were common since St. Athanasius at least both in the West and in the East. The term "cause", when applied to the Father, indicates a free, willing and personal agent, whereas the language of "source" or "principle" can convey a more "natural" and thus impersonal imagery (the homoousios was interpreted in this impersonal way by several people in the fourth century). This point acquires crucial significance in the case of the Filioque issue. In the Byzantine period the Orthodox side accused the Latin speaking Christians, who supported the Filioque, of introducing two Gods, precisely because they believed that the Filioque implied two causes--not simply two sources or principles--in the Holy Trinity. The Greek Patristic tradition, at least since the Cappadocian Fathers, identified the one God with the person of the Father, whereas, St. Augustine seems to identify Him with the one divine substance (the deitas or divinitas). It is of course true that, as the Vatican document points out, the Fourth Lateran Council excludes any interpretation that would make divine substance the source or cause, of the Son's generation and the, Spirit's procession. And yet the Cappadocian idea of "cause" seems to be almost absent in the Latin theological tradition. As Saint Maximus the Confessor insisted, however, in defence of the Roman use of the Filioque, the decisive thing in this defence lies precisely in the point that in using the Filioque the Romans do not imply a "cause" other than the Father. The notion of "cause" seems to be of special significance and importance in the Greek Patristic argument concerning the Filioque. If Roman Catholic theology would be ready to admit that the Son in no way constitutes a "cause" (aition) in the procession of the Spirit, this would bring the two traditions much closer to each other with regard to the Filioque. c) Closely related to the question of the single cause is the problem of the exact meaning of the Son's involvement in the procession of the Spirit. Saint Gregory of Nyssa explicitly admits a "mediating" role of the Son in the procession of the Spirit from the Father. Is this role to be expressed with the help of the preposition ??? (through) the Son (?? ??????? ??'?????), as Saint Maximus and other Patristic sources seem to suggest? The Vatican statement notes that this is "the basis that must serve for the continuation of the current theological dialogue between Catholic and Orthodox". I would agree with this, adding that the discussion should take place in the light of the "single cause" principle to which I have just referred. 3. 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). Is this enough? Or should we still insist that the Filioque be removed also from the Latin text of the Creed? It would seem difficult to imagine a situation whereby Greek and Latin Christians would recite the Creed together without using a common text. At the level of theologians, however, the clarifications made by the Vatican statement with regard to this matter are extremely helpful and can be very useful for the theological dialogue between Orthodoxy and Roman Catholicism. 4. The last part of the document, which describes the Spirit as the Gift of love from the Father to the Son and tries to expand on the Augustinian nexus amoris, presents considerable difficulties to me. On the one hand the document refers to the irreversible Trinitarian order according to which the Spirit can be called "the Spirit of the Son" while the Son can never be called "the Son of the Spirit" (Gregory of Nyssa, Maximus etc.). On the other hand, however, the same document describes the Spirit as the eternal gift of love from the Father to the Son on the basis of Biblical texts all of which clearly refer to the divine economy, and not to the immanent Trinity. We seem to encounter here the usual difficulty between Western and Eastern theological tradition, namely the problem of the distinction between the eternal and the economic level of God's being. The implications of this problem are far-reaching and cannot be analyzed here. Suffice it to say that the Filioque at the level of the economy presents no difficulty whatsoever to the Orthodox, but the projection of this into the immanent Trinity creates great difficulties. The reference to the well known passage from Saint Gregory Palamas describing the Spirit as "some kind of love (eros - ?????)" of the Father towards the Son or to that from St. John of Damascus who speaks of the Spirit as "resting" (???????????? - anapauomenon) in the Son, should not be justified on the ground of the economy. Neither of these two theologians bases the above references to the Spirit's relation to the Son on the relation of these two Persons in the Economy, as St. Augustine seems to do and as the Vatican document also does. The Filioque in no way can be projected from the Economy into the immanent Trinity, and the same is true also of any form of Spirituque that might be detected - this is in fact possible - from the relation of Christ to the Spirit in the history of salvation. This makes it difficult to subscribe to the statements of the document such as this: "This role of the Spirit in the innermost human existence of the Son of God made man derives from an eternal Trinitarian relationship through which the Spirit, in his mystery as Gift of love, characterizes the relation between the Father as source of love, and his beloved Son". 5. When it refers to the work of the Spirit in relation to that of Christ at the level of the Economy the Vatican statement is in my opinion extremely helpful. The idea that the Spirit brings us into the filial relationship of the Father and the Son making us sons of the Father by grace through the "spirit of sonship", and that the constant invocation of the Spirit is necessary for the realization of the work of Christ in us, shows that the East and the West can reach a common ground in many areas of Pneumatology in spite of any obscurities and difficulties that may still remain with regard to the Filioque issue. In conclusion, the Vatican document on the procession of the Holy Spirit constitutes an encouraging attempt to clarify the basic aspects of the Filioque problem and show that a rapprochement between West and East on this matter is eventually possible. An examination of this problem in depth within the framework of a constructive theological dialogue can be greatly helped by this document.