I hope that readers will not be confused by the technical nature of this book. John Zizioulas does address the most contemporary, the most urgent, the most essential problems facing the Orthodox Church today. As long as the visible reality of the life of our Church does not correspond to the communion revealed to us in the Eucharist, until our ecclesial structures, especially here in the West, themselves correspond to what the Church really is, until the Eucharistic nature of the Church is freed from the layers of anachronism and ethnic politics, which hides it today, no ecumenical witness, no authentic mission in this world is possible.

Born in Greece in 1931, John Zizioulas graduated from the Faculty of Theology of the University of Athens, where he later received a doctorate in theology for his work "The Unity of the Church in the Eucharist Bishop in the First Three Centuries" (Athens, 1965). He also studied patristics at Harvard and was a member of the Center for Byzantine Studies at Dumbarton Oaks. For several years he served on the staff of the Faith and Order Commission of the World Council of Churches and gradually became recognized as one of the most influential Orthodox theologians of the younger generation. As a representative of the Ecumenical Patriarch, he is a member of the International Commission for Dialogue with Roman Catholicism. His ecumenical involvement led him to publish a number of articles and studies in various periodicals. Some of these articles appeared in the French book Ecclesiastical Life (Paris, 1981). The same articles with important additions are included in this book.

John Zizioulas is currently Professor of Theology at the University of Glasgow. He was recently appointed a part-time lecturer at the University of Thessaloniki.

Introduction

The Church is not just an institution. It is a "mode of existence," a mode of being. The mystery of the Church, even in its institutional aspect, is deeply connected with the existence of man: with the existence of the world and the very existence of God. Because of this connection, so characteristic of patristic thinking, ecclesiology is of marked importance and significance not only for all aspects of theology, but also for the existential needs of man in each age.

First of all, the existence of the Church is connected with the very existence of God. Proceeding from the fact that a person is a member of the Church, he becomes the "image of God", he exists as God himself exists, he perceives the "mode of existence" of God. This way of being is not a moral achievement, something that a person does. It is a way of relating to the world, to other people, and to God, an event of communion: this is why it should not be regarded as an achievement of an individual, it is a fact of the Church.

However, for the Church to represent this mode of existence, it must itself be an image of the way in which God exists. Its whole structure, its ministry, etc., must express this mode of existence. And this means, first of all, that the Church must have the right faith, the correct vision of God's existence. Orthodoxy in relation to the problem of God's existence is not a luxury for the Church and man: it is an existential essential necessity.

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During the patristic period, there was hardly even a mention of the existence of the Church, although much was done about the concept of the existence of God. The question that preoccupied the Church Fathers was not to find out whether God exists or not; the existence of God was "given" to almost all people of that period, both Christians and pagans. The question that has tormented all generations has been rather how He existed. And such a question had immediate consequences both for the Church and for man, since both were regarded as "images of God."

It was not easy to answer the question about the existence of God and the patriotic period. The greatest difficulty was also rooted in ancient Greek ontology, which was fundamentally monistic; the existence of the world and the existence of God for the ancient Greeks represent an indissoluble unity. This linked together the existence of God and the existence of the world, while biblical faith proclaimed God to be absolutely free in relation to this world. Plato's concept of God the Creator did not satisfy the Church Fathers, precisely because of the doctrine of creation from primordial matter, which limited divine freedom.

It was therefore necessary to find some ontology that would avoid both the extremes of monistic Greek philosophy and the "gap" between God and the world, as taught by the Gnostic systems, which was the other great danger of this period. The creation of such an ontology was perhaps the greatest philosophical achievement of patristic thinking.

The ecclesial experience of the Church Fathers played a decisive role in breaking through ontological monism and avoiding the Gnostic "rupture" between God and the world. The fact that neither apologists such as Justin Martyr nor Alexandrian catechetical theologians such as the famous Clement and Origen were able to completely avoid the trap of the ontological monism of Greek thought is not accidental; They were above all "doctors", they were academic theologians fundamentally interested in Christianity as a "revelation". By contrast, the bishops of this period, theologians and pastors such as St. Ignatius of Antioch, and most importantly St. Irenaeus and later Athanasius, approached the existence of God through the experience of church community, through the experience of ecclesiastical existence. This experience revealed something very important; the existence of God cannot be known only through personal relationships and through personal love. Being means life, and life means communion.

This ontology, which proceeded from the Eucharistic experience of the Church, guided the Fathers in the elaboration of their teaching on the existence of God, a teaching formed above all by Athanasius of Alexandria and the Cappadocian Fathers; Basil

the Great, Gregory of Nazianzus and Gregory of Nyssa. Below is a brief summary of the result of this important philosophical development, which would not have been possible without the experience of the Church, and without which ecclesiology would have lost its deep existential meaning.