Many of the differences between East and West can be at least partially attributed to the different roles monasticism takes in the two churches. Here is John Paul II, Orientale Lumen:
In the East, monasticism has retained great unity. It did not experience the development of different kinds of apostolic life as in the West. The various expressions of monastic life, from the strictly cenobitic, as conceived by Pachomius or Basil, to the rigorously eremitic, as with Anthony or Macarius of Egypt, correspond more to different stages of the spiritual journey than to the choice between different states of life. In any event, whatever form they take, they are all based on monasticism.
Moreover, in the East, monasticism was not seen merely as a separate condition, proper to a precise category of Christians, but rather as a reference point for all the baptized, according to the gifts offered to each by the Lord; it was presented as a symbolic synthesis of Christianity.
When God’s call is total, as it is in the monastic life, then the person can reach the highest point that sensitivity, culture and spirituality are able to express. This is even more true for the Eastern Churches, for which monasticism was an essential experience and still today is seen to flourish in them, once persecution is over and hearts can be freely raised to heaven. The monastery is the prophetic place where creation becomes praise of God and the precept of concretely lived charity becomes the ideal of human coexistence; it is where the human being seeks God without limitation or impediment, becoming a reference point for all people, bearing them in his heart and helping them to seek God.
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Monasticism has always been the very soul of the Eastern Churches: the first Christian monks were born in the East and the monastic life was an integral part of the Eastern lumen passed on to the West by the great Fathers of the undivided Church.
In the West, when monastics came up against the hierarchy, they usually lost. As a result, they found themselves on the fringe of the church. In many cases, these monastics tried to carve a place for themselves further toward the center by disavowing monasticism, and taking up activism instead. No longer did they live in quiet prayer, having adopted instead the role of evangelist. By the time we got to the twentieth century and Vatican II, many of these monastics-in-name-only threw off what remained of their monasticism, and became some of the most raucous proponents of Marxist activism in the church.
The history of monasticism in the Eastern church was very different. Monastics usually won when they found themselves pitted against hierarchs in the East, and cemented for themselves a central place in the church. Monastics had no need to find another calling other than contemplative prayer, because they had never been pushed to the margins of the church. The people put their faith in the monks and nuns first, as they do today. Whereas many ascetes in the West were at the forefront of the movement to protestantize the church, and substitute Marx for Christ, ascetes in the East have always been, and remain, the solid, stable, and most conservative core of Eastern Christianity.
Today, monastics have very little influence on the Western church, whereas they are the very heart and soul of the Eastern church. It is no accident that we pull our bishops from monasteries, and even after they are consecrated, they dress like monks.
The strong influence of asceticism can be seen in several ways. One is the more rigorous and central place abstention and fasting take in Eastern Christianity. It isn’t because we are better Christians, necessarily, and it isn’t the influence of Vatican II, since abstention and fasting have had a far more important and central role in the East from hundreds of years before the council. The difference stems from the fact that asceticism is seen in the East, as John Paul II puts it, “In the East, monasticism was not seen merely as a separate condition, proper to a precise category of Christians, but rather as a reference point for all the baptized.” We are not expected to live up to the same standards as our monks and nuns, but we are expected to live up to a standard approching that of our monastics. We are expected to abstain from meat, fish, eggs, and dairy on Wednesdays and Fridays, to abstain from those plus alcohol and olive oil throughout “fasting periods” such as Great Lent or Nativity Lent (Advent), and we are expected to fast entirely before receiving Holy Communion.
It is also no accident that while in the West, the Liturgies of the Hours are seen as “monastic” services and are rarely done in parishes, while Vespers and Matins are a part of nearly every Orthodox parish’s weekly services.
Further reading: Fr. Florovsky, The Ascetic Ideal and the New Testament