"Indeed, the Christian catacombs stand testament to the early belief in a purgatorial state and the merit of prayer, fasting and Holy Liturgy for the faithfully departed."
Well, certainly of an intermediate state; I don't think I'd apply the adjective "purgatorial" to it, but it might be a way to look at it if the fire of God's love about which the Fathers speak has an effect in that "place of the dead". It seems to me it might because as +Isaac the Syrian teaches
"I say that those who are suffering in hell, are suffering in being scourged by love. ... It is totally false to think that the sinners in hell are deprived of God's love. Love is a child of the knowledge of truth, and is unquestionably given commonly to all. But love's power acts in two ways: it torments sinners, while at the same time it delights those who have lived in accord with it." Homily 84
And +Symeon the New Theologian writes:
"Can a man take fire into his bosom, and his clothes not be burned says the wise Solomon. And I say: can he, who has in his heart the Divine fire of the Holy Spirit burning naked, not be set on fire, not shine and glitter and not take on the radiance of the Deity in the degree of his purification and penetration by fire? For penetration by fire follows upon purification of the heart, and again purification of the heart follows upon penetration by fire, that is, inasmuch as the heart is purified, so it receives Divine grace, and again inasmuch as it receives grace, so it is purified. When this is completed (that is, purification of heart and acquisition of grace have attained their fullness and perfection), through grace a man becomes wholly a god."
Now if the fire of God's love torments those in hell, could it also purify the souls in the intermediate state as it surely does while we are alive? I don't know the answer to that. I do think its important, at least from an Orthodox pov, to avoid any use of the word "merit", since the reception of God's grace/love has nothing whatsoever to do with "merit" nor do I think that Orthodoxy would ascribe to the notion that my fasting somehow benefits a soul in that intermediate place, though it certainly benefits us the living. Begging God for mercy on their souls in the Liturgy or Memorial Services and Funerals is another matter all together.
Purgatorial or Purificatory. Merit or value. Great post on your part.
The perfection of theosis in the place of the dead is a matter of grace, to be sure. The faithfully departed experience the pain of expectation of heaven that comes with the knowledge that their shortcomings stand in the way.