The Orthodox Church is regarded as the body of Christ. It is an organic, living entity made alive by the indwelling of the Holy Spirit in the individual members that make up the Church. Since the Church is the body of Christ, and corporate liturgical worship is central to the life of this body, then it is possible to answer the question of "What is liturgical theology?" in biological terms. It is the goal of this author to uniquely define liturgical theology as the anatomy (structure) and physiology (function) of church worship and its role in a life in Christ.
In biological sciences, anatomy is the study of structure and the relationships of structures to each other. One can investigate an individual structure (jaw bone) or one can study several structures together (skull) to determine how they relate to each other. Similarly, it is possible to think of liturgical theology as the anatomy of worship. The student of liturgical theology is able to study the structure(s) of worship and determine their importance in the life of the Church.
As in biology, the anatomical aspects of liturgical theology are manifested in many different ways. One aspect of liturgical theology involves the study of the basic structure and/or the rubrics (rules of structure) of worship services. One learns the shape, or anatomy, of the Divine Liturgy, the Matins services, the Vespers services, etc. Further elaboration on this aspect of liturgical theology allows one to study the structure of one worship service and compare it to others. For example, one could study Matins and Vespers to see how they are similar/different in structure and rubrics. In anatomy, the analogy would be that of studying the arm bones and the leg bones in a human to see how they are related structurally. As there is comparative anatomy, there is also comparative liturgical theology. In comparative anatomy, one might study the leg bones of human and compare them to the leg bones of a cat looking for similarities/differences in structure. In liturgical theology, one could "dissect" the Divine Liturgy of St. John Chrysostom and study that in relation to the "anatomy" of the Coptic Orthodox Divine Liturgy of St. Basil likewise looking for similarities/differences in structure.
It is rather unfortunate that in many theological schools, liturgical theology has become nothing more than the study of the structure of worship. It has been reduced to an almost technical science and has lost touch with its relationship to the faith and worship of the Church. In this "stripped down" study of liturgical theology we are made aware only of the anatomy and, perhaps, of the symbolism (however weakly it is interpreted) of the worship, i.e. the Gospel reading comes after the Small Entrance and it supposedly symbolizes Christ's preachings. When this happens, though, there exists the danger of dreadful liturgical practices/reforms entering into the church and subtracting from the true worship and true faith of the Orthodox Church. This can occur because of those who think that, after all, worship is ""only structure and symbolism". This mode of thinking is corrected if one is made aware of liturgical theology as not only the anatomy of liturgical worship, but also the "physiology of liturgical worship."
In biological sciences, physiology is the science of the function and activity of living structures and organisms. One can study anatomy for years, but the true beauty of that science is only made relevant in the light of the understanding of the physiology, i.e. the function. For example, one can study the anatomy of heart on both the gross and the microscopic levels, but to truly understand the heart, one must also learn its function and activity within the body. Likewise with liturgical theology, to truly understand the beauty of the worship services, one must understand their function within the body of Christ. Therefore, liturgical theology can not function on just a symbolic or structural or "anatomical level". It must have function and it must give theological meaning to the worship.
One aspect of that function is to transform the world and make it the kingdom of God on earth. Liturgical theology makes evident the fact that the life and worship of the Church is an icon of the kingdom of heaven. Those of us who gather to worship form the Church Militant on earth. We are not separate from the kingdom of heaven, but rather, through our worship and through the power of the Holy Spirit, we are worshipping with the Church Triumphant that lives and dwells with the Holy Trinity. Through liturgical worship, the Church on earth is made an integral part of the great cosmic Church. One sees here an example of form (anatomy) and function (physiology) going hand in hand.
Liturgical theology also functions to make Christ's life, death and resurrection a real event for us and a real event that we can participate in as a church, as the body of Christ. For example, baptism must not be seen as simply a complex initiation ritual into the Church, but must be seen as our participation in the death and the Resurrection of Christ wherein mankind is "born again" as a new creature. Again, this illustrates the importance of both form and function together.
Liturgical theology also allows us to understand how all of the worship relates to those who gather for the corporate worship of the Church. The word liturgical, which is used to describe our worship, is derived from the Greek "leitourgia" which means "the work of the people." Liturgical theology presents the worship and prayer life of the Church as a functional whole. Just as one can study the physiology of the heart, blood, brain and kidneys and unify them to understand the function of how the body regulates blood pressure. It is the Holy Spirit, manifesting Himself through the Church, that gives function and meaning to the liturgical worship and calls us to be participants - not observers - in the kingdom of God so that we are able to partake in a new life in Jesus Christ and to experience those salvific events while we are here on earth and while we are actively involved in the liturgical worship of the Church.
Another important aspect of liturgical theology is its ability to expound the faith and doctrines of the Church. Liturgical theology takes liturgical worship and the hymnography of the Church and uses it as a powerful means to expound upon the teachings and doctrines of the Church. This is most evident in the complex hymnography in the Orthros and Vespers services. For example, the hymnography associated with Pentecost is full of theology and teaching concerning the Holy Spirit - another example of form (the service) having function (teaching theology).
In conclusion, it is important that one fully comprehends the role of liturgical theology in the worship of the Church. Just as anatomy and physiology give understanding to the form and function of life, likewise liturgical theology gives to us the understanding of the form and function of the worship services of the Orthodox Church and enables us to fully live with Christ in the heavenly kingdom here on earth. In any living organism, without organized structure there is no function, and without structure and function there is no life. The same thing can be said about liturgy. Without structure and function there is no life to the Church and without life in the Church there is no salvation.
Fagerberg, D., What is Liturgical Theology? A study in Methodology. (Collegeville: Liturgical Press, 1992). Schmemann, A., Introduction to Liturgical Theology. 3rd edition. (Crestwood, NY: SVS Press, 1986). Schmemann, A., Liturgy and Tradition. (Crestwood, NY: SVS Press, 1990). Taft, R., Beyond East and West; Problems in Liturgical Understanding.(Washington, DC; Pastoral Press, 1984).