"I am not the first to make the observation that in Eastern Christian theology (except when under strong Western influence), there is no place for original guilt and this has significant implications for the understanding of the nature of man, the soul, and God."
This is very true. There is a significant place, however, for the effects of the ancestral sin, which brought death, corruption, and the tendency to sin into the world.
What St. John C. is speaking of in that passage is the act of the will in turning one's face toward or away from God. The "sudden" transformation of which he speaks is not the result of our will making the transformation, but the effect of opening oneself to receiving God's grace or cutting oneself off from it through an act of the will.
To a great extent, in this life, Orthodoxy would seem to indicate that our free choice is primarily restricted to an unending series of choices that will either turn us toward God or away from him.
In the next life, we certainly do not believe that this will be the case. There, we will have the freedom to choose between many goods, something of which we catch only glimpses in this life.
The reason for the quotes was to bring out a distinction between Western and Eastern Christian theology, not to ignore that men and women do commit sins. Here's the way John Meyendorff explains the Eastern perspective in Byzantine Theology:
There is indeed a consensus in Greek patristic and Byzantine traditions in identifying the inheritance of the Fall as an inheritance essentially of mortality rather than of sinfulness, sinfulness being merely a consequence of mortality. The idea appears in Chrysostom, who specifically denies the imputation of sin to the descendants of Adam...sin remains for Maximus [the Confessor] a personal act, and inherited guilt is impossible. For him, as for the others, "the wrong choice made by Adam brought in passion, corruption, and mortality," but not inherited guilt.In Western theology, mankind indeed inherits guilt for the sin of Adam.The difference in perspective has other consequences as well. Most Western Christians have a juridical understanding of the Crucifixion. Christ receives the punishment that sinful mankind deserves. But I have not seen this juridical understanding of the Crucifixion emphasized in Eastern Christianity. Here is how Meyendorff puts it:
The point [of the Crucifixion] was not to satisfy a legal requirement, but to vanquish the frightful cosmic reality of death, which held humanity under its usurped control and pushed it into the vicious circle of sin and corruption. And as Athanasius of Alexandria has shown...God alone is able to vanquish death, because He "alone has immortality." Just as original sin did not consist in an inherited guilt, so redemption was not primarily a justification, but a victory over death.The point of view on inherited guilt and the Crucifixion and many other topics has a somewhat different orientation in Eastern and Western Christian theology. And I think all Western Christians could deepen their understanding of Christianity by reading Eastern theology with an open mind.