Eastern Orthodoxy lays great stress on inwardness, the mysteriousness of God and His incomprehensible ways. The Cappadocian Fathers reveled in the paradoxical nature of the Trinity. For these men, the doctrine's truthfulness is ineffable, but salvific:
"When I think of any one of the three I think of him as the whole, and my eyes are filled, and the greater part of what I am thinking escapes me. I cannot grasp the greatness of that one so as to attribute a greater greatness to the rest. When I contemplate the three together, I see but one torch, and cannot divide or measure out the undivided light" Gregory Nazianzius).
Gregory of Nyssa writes: "Now if any one should ask for some interpretation, and description, and explanation of the Divine essence, we are not going to deny that in this kind of wisdom we are unlearned, acknowledging only so much as this, that it is not possible that that which is by nature infinite should be comprehended in any conception expressed by words" (Against Eunomius 3.5).
What are we to think about a view that focuses on inwardness to the almost total exclusion of exteriority? To illustrate what I'm pinpointing here, consider the example of Bernard of Clairvaux (a French abbot who was canonized in 1174 CE) and Peter Abelard (a philosopher-theologian of the Middle Ages). Both men were Trinitarians, but Abelard highly valued reason, whereas Bernard preferred a mystical approach to God--one that was primarily spiritualistic. The result was that Bernard viciously opposed Abelard, which evidently contributed to the latter's physical demise.
Karen Armstrong cites the painful lesson learned from this telling episode of religious history:
"Bernard, however, seemed afraid of the intellect and wanted to keep it separate from the more emotional, intuitive parts of the mind. This was dangerous: it could lead to an unhealthy disassociation of sensibility that was in its own way just as worrying as an arid rationalism" (A History of God, p. 203-204).
While I have no desire to worship at the altar of rationalism or evidentialism, I believe that rationality plays an important part in worship to God (Rom. 12:1, 2). For the aforementioned reasons, I have a problem with the Eastern approach to worshiping and serving God.