I do not understand the Orthodox objection to purgatory as lying in the possiblity that the character of the Particular Judgement (hades or paradise, corresponding presumptively to Heaven or Hell as manifested when the river of fire comes forth from the throne of God) might be improved before or at the Final Judgement by the prayer of the Church--that is a protestant objection--but that there is a created means of cleansing souls from sin (the effect of the prayer of the Church coming from the Holy Spirit rather than our mere human beseaching of God's mercy).
I have read parts of it and I find his "arguments" anecdotal rather than convincing. Such as such has a vision., and the vision told him...is not theology.
The Church simply has nothing to offer to show that something can be done for the soul that has been saved but not perfected by God! Orthodox Catechism (Rev. George Mastrantonis, 1969, Logos) says this:
In both cases the issue is of the betterment of the living, not the dead. The idea for the dead may come from the Jewish practice of "sin offerings" (but let's not forget that their idea of salvation is different).
Maccabees 12:43b-45, Septuagint, identifies prayers for the dead as "sin offerings" made for the "atonement for the dead, so that they might be set free from their sin."
Catechism also continues by saying that "Scripture does not indicate clearly the practice of offering prayers for departed souls. (p.157) There is one references in Zachariah 1:12-13 where an angel asks God "how long wilt though be without mercy..." -- a strange reference, indeed, suggesting that God is without mercy (but we will let that one go for no).
Furthermore, the Catechism says:
On the bottom of the same page, "As faith and prayers are indispensable for the living, prayers of the Church could be beneficial to departed souls. This practice of praying to God for the dead in commemorations is consistent with the divine justice and satisfaction, although the human mind cannot comprehend how these prayers help." (pp. 158-159)
I would also add to TRD's recommendation of Fr. Seraphim's book yet another standard work: "The Mystery of Death," written by the Greek theologian Nikolaos P. Vassiliadis, and published by the Orthodox Brotherhood of Theologians "O Sotir."
This is a rather encyclopedic work that is chock-full of Scriptural and patristic citations. It has a little different flavor than does Fr. Seraphim's work, since it is written out of the Greek monastic tradition. Both are very worth reading, and both are solidly in the Orthodox patristic tradition.
The section on prayers for the dead, commemorating the dead at the Liturgy, and memorial services has abundant patristic citations regarding why we do this.
One interesting quotation from St. Gregory of Nyssa:
Nothing that is unreasonable and unprofitable has been handed down by the disciples and preachers of christ and kept everywhere in the Church of God. A thing that is in every way beneficial and pleasing to God is of course the commemoration in the divine services of those who have fallen asleep in true faith.
From St. John Chrysostom:
Those who depart in sin to where it is not possible to receive cleansing, are not completely without hope... Let us help them according to our ability; let us provide for them some assistance, however small, that will be of some help to them. How and in what way? By praying for them, and by encouraging others to pray for them too.
St. Athanasius says that the souls receive benefit, but "as only our God who has authority over the living and the dead knows and ordains."
The author summarizes by saying:
While the Mother Church prays also for sinners, it does not teach nor promise that those who departed unrepentant will receive forgiveness of sins. Also, the Fathers, who are made wise by God and who advise us to pray for the sinners, do not support the view that with these prayers and memorials will we absolve them from the sufferings of Hades or remove them from the place of punishment to Paradise. They only note that those who depart from this life with their sins, receive through all of these prayers a certain consolation..."
Regarding purgatory, Vassiliadis' comments boil down to these points:
1. The fires of purgatory happen as a result of penances not being completed, and in the Latin language, of full atonement not having been made for sins. The implication could be drawn that a full atonement has not been made by the redemptive work of Christ.
2. It means that when we confess our sins and receive Christ's absolution, we aren't really forgiven and it isn't finished until the penance is made. By contrast, any discipline placed on one by a father-confessor in the Orthodox tradition are pedagogical means and therapeutic medicines which the priest as a compassionate father and experienced spiritual physician, imposes, in order to help the penitent become fruitful in works worthy of his repentance.
3. The punishing fires of purgatory affect only the soul, and not "the body which was used as an instrument for committing the sin", which remains unpunished. By Orthodox lights, a person neither experiences full bliss nor full torment until the soul is reunited with the body at the Last Judgment after the resurrection.
In summary, the heart of at least some Orthodox objections to the idea of purgatory is portraying this as punishment that needs to be completed, that involves suffering and pain. Its being linked to uncompleted penances that need to be "paid up" and completed is outside the pale of Orthodox thought. I would add that according to this doctrine, it would seem that once the purgatorial time is completed, whether by the passage of time, or by the application of a plenary indulgence, there is really no further benefit to praying for the departed. By contrast, the Orthodox perspective is that the dead continue to benefit, in an undefined and unguaranteed way, from our prayers until the time of the Last Judgment.
This is yet another example of a place where the Orthodox Church finds that in the course of attempting to over-define a doctrine, the point to the traditional teachings and practices can actually be lost.