I am not going to engage greekischristian's original theological arguments, which elsewhere he boasts may be superior to the fathers, but I will only engage his claimed support from the fathers and Church history.
1. Origen's apokatastasis was condemned at the Fifth Ecumenical Council:
The fact of the matter is that an anathema of Apokatastasis is not included in the Anathemas against Origen, so by your logic I could essentially argue that because (if I recall properly) Nestorius believed in an eternal hell, the anathemas against Nestorius at Ephesus can clearly be construed as an anathema against the belief in an eternal hell.
First, there is Emperor St. Justinian the Great's ninth anathema against Origen:
IX. If anyone says or thinks that the punishment of demons and of impious men is only temporary, and will one day have an end, and that a restoration (apokatastasis) will take place of demons and of impious men, let him be anathema.
greekischristian has replied that this was not ratified by the Ecumenical Council, but only taken into consideration. This may be so, but we should surely not take an anthema pronounced by a Saint lightly.
Next, we have the fourteenth anathema against Origen of the Fifth Ecumenical Council:
XIV. IF anyone shall say that all reasonable beings will one day be united in one, when the hypostases as well as the numbers and the bodies shall have disappeared, and that the knowledge of the world to come will carry with it the ruin of the worlds, and the rejection of bodies as also the abolition of [all] names, and that there shall be finally an identity of the gnpsis and of the hypostasis; moreover, that in this pretended apocatastasis, spirits only will continue to exist, as it was in the reigned pre-existence: let him be anathema.
greekischristian asserts that this is not the position he holds (and by implication Origen), but that of Plotinus that is being condemned, since it denies the resurrection of the body. It is strange that an anathema against Plotinus would be included in the anathemas against Origen, so in what did Origen's apokatastasis actually consist? From Adolf von Harnack's History of Dogma, Volume II
Origen’s eschatology occupies a middle position between that of Irenæus and the theory of the Valentinian Gnostics, but is more akin to the latter view. Whilst, according to Irenaeus, Christ reunites and glorifies all that had been severed, though in such a way that there is still a remnant eternally damned; and, according to Valentinus, Christ separates what is illegitimately united and saves the spirits alone, Origen believes that all spirits will be finally rescued and glorified, each in the form of its individual life, in order to serve a new epoch of the world when sensuous matter disappears of itself. Here he rejects all sensuous eschatological expectations. He accepted the formula, “resurrection of the flesh”, only because it was contained in the doctrine of the Church; but, on the strength of 1. Cor. XV. 44, he interpreted it as the rising of a “corpus spiritale”, which will lack all material attributes and even all the members that have sensuous functions, and which will beam with radiant light like the angels and stars. Rejecting the doctrine that souls sleep, Origen assumed that the souls of the departed immediately enter Paradise, and that souls not yet purified pass into a state of punishment, a penal fire, which, however, like the whole world, is to be conceived as a place of purification. There is another and intermediate stage between the punishments in hell and regnum dei. In this way also Origen contrived to reconcile his position with the Church doctrines of the judgment and the punishments in hell; but, like Clement, he viewed the purifying fire as a temporary and figurative one; it consists in the torments of conscience. In the end all the spirits in heaven and earth, nay, even the demons, are purified and brought back to God by the Logos-Christ, after they have ascended from stage to stage through seven heavens. Origen does not mention them, so far as I know. Hence Origen treated this doctrine as an esoteric one: “for the common man it is sufficient to know that the sinner is punished.”
So from this we see that Origen's doctrine was quite specifically and in detail condemned by the Fifth Ecumenical Council, while St. Justinian's anathema was general.
2. Patristic support for apokatastasis is considerably less than greekischristian makes it out to be:
The fact that you believe in a 'consensus patrum' demonstrates that either you have not adequately studied Church history or that you know better and use such arguments to strengthen a weak point. Furthermore, if you are trying to make such a point, the fact that two of the three great Cappadocians, Gregory of Nyssa and Gregory the Theologian, as well as the Catechetical School of Alexandria, and in the west no less a significant figure than St. Ambrose of Milan all advocated the theology and that St. Basil tells us that during his time apokatastasis was a theological posistion held by the majority of the Church, pretty much dismisses your argument about there being consensus on the matter. The doctrine of apokatastasis only fell out of favour when it became necessary to use Christianity as a means to control the masses; certainly an understandable development for the time, but now that we no longer have need of the Church for that purpose, the social danger of moving away from fear towards proper Christian Soteriology is minimal.
First, St. Gregory of Nyssa did not actually hold this view, as Metropolitan Hierotheos Vlachos shows in his book, Life After Death, and he appeals to Ss. Maximos the Confessor and Mark of Ephesus' readings of St. Gregory of Nyssa in support of his own. The relevant section can be read here
From the conclusion:
To conclude this chapter we should summarise the most basic points on the subject that we have developed.
First. The teaching of St. Gregory of Nyssa concerning the restoration of all things and the purifying fire should be seen within the teaching of St. Basil the Great and St. Gregory the Theologian about Paradise and Hell. One cannot isolate him from the other two saints who are bound together with him by brotherly and friendly ties. Perhaps St. Gregory of Nyssa developed these views further and in philosophical language, answering philosophical questions and problems, but he did not depart from a reality also affirmed by other saints, that is, St. Maximus the Confessor and Mark Eugenicus.
Second. God's love, philanthropy and goodness are His uncreated energy, which will be sent to both the just and the unjust in the future life. But this love will be experienced differently. The righteous will participate in God, while those not cured will see God but have no participation and communion with Him.
Third. Evil will be nonexistent, since even today evil is the absence of good and alienation from it. Night does not exist ontologically, but it is the absence of the sun. When the sun of righteousness appears, then there will be no evil. Death will also be abolished - death from which infinite evils, many passions and sins are produced. The fact that evil will be non-existent does not mean that sinners and uncured souls will not exist. Man's existence is one thing, and another thing is his participation and communion with God, which constitutes true life.
Fourth. At the Second Coming of Christ nature will be restored, but the will will not be restored. All will gain immortality, the bodies of all will rise again, but the will and man's personal opinion will not change. They will continue there too according to the choice with which they lived in their biological life. Even the sinners will have knowledge of God, will see God, but they will not have participation. Punishment is not the absence of God, but non-participation in God, the presence of God as a fire.
Fifth. For those people who have entered the stage of purification before their death, perfecting will continue in the next life as well. Perfection is endless. It has no end and completion. Moreover, human nature is limited, while God is infinite.
Sixth. There is a heretical restoration of all things, as Origen believed and which the Church condemned, and there is an Orthodox restoration of all things, as St. Gregory of Nyssa and St. Maximus the Confessor teach it. According to the latter, all men will recognise God in the Second Coming, but they will not all have a share in God. All will rise again, but they will not all glorify Him. Christ's resurrection is a gift which was given to all, but the ascension will be experienced only by the saints. Therefore in all there will be a restoration of nature, which will remain forever, immortal, but there will not be a restoration of the will, since each person will perceive Christ according to his choice.
St. Gregory of Nyssa's theology concerning the last things, concerning the Kingdom of God, is transluscent and orthodox. It cannot be said that this great Father and theologian follows the heretical teachings of Origen about the restoration of all things, because St. Gregory of Nyssa is organically bound up with the whole orthodox, ecclesiastical tradition.
Now, concerning Ss. Ambrose of Milan and Gregory the Theologian, R. Grant Jones' "Dialogues and Articles on the Afterlife
" (unfortunately only available through Internet Archive) is very relevant.
St. Ambrose of Milan:
"Now let the Manichaean have his word. 'I hold that the devil is the creator of our flesh.' The Lord will answer him: 'What, then, doest thou in the heavenly places? Depart, go thy way to thy creator. My will is that they be with Me, whom my Father hath given Me. Thou, Manichaean, holdest thyself for a creature of the devil; hasten, then, to his abode, the place of fire and brimstone, where the fire thereof is not quenched, lest ever the punishment have an end.
'" Nicene and Post-Nicene Fathers, Second Series, Volume 10, On the Christian Faith - Book II, page 239.http://web.archive.org/web/20010619041327/www.geocities.com/r_grant_jones/Rick/damnation1.htm
St. Gregory the Theologian:
"I know the emptying, the making void, the making waste, the melting of the heart, and knocking of the knees together, such are the punishments of the ungodly. I do not dwell on the judgments to come, to which indulgence in this world delivers us, as it is better to be punished and cleansed now than to be transmitted to the torment to come, when it is the time of chastisement, not of cleansing. For as he who remembers God here is conqueror of death (as David has most excellently sung) so the departed have not in the grave confession and restoration; for God has confined life and action to this world, and to the future the scrutiny of what has been done.
Gregory Nazianzen, Oration 16, Section 7, NPNF Series 2, Vol 7
"But then what advocate shall we have? What pretext? What false excuse? What plausible artifice? What device contrary to the truth will impose upon the court, and rob it of its right judgment, which places in the balance for us all, our entire life, action, word, and thought, and weighs against the evil that which is better, until that which preponderates wins the day, and the decision is given in favour of the main tendency; after which there is no appeal, no higher court, no defence on the ground of subsequent conduct, no oil obtained from the wise virgins, or from them that sell, for the lamps going out, no repentance of the rich man wasting away in the flame, and begging for repentance for his friends, no statute of limitations; but only that final and fearful judgment-seat, more just even than fearful; or rather more fearful because it is also just; when the thrones are set and the Ancient of days takes His seat, and the books are opened, and the fiery stream comes forth, and the light before Him, and the darkness prepared; and they that have done good shall go into the resurrection of life, now hid in Christ and to be manifested hereafter with Him, and they that have done evil, into the resurrection of judgment, to which they who have not believed have been condemned already by the word which judges them. Some will be welcomed by the unspeakable light and the vision of the holy and royal Trinity, Which now shines upon them with greater brilliancy and purity and unites Itself wholly to the whole soul, in which solely and beyond all else I take it that the kingdom of heaven consists. The others among other torments, but above and before them all must endure the being outcast from God, and the shame of conscience which has no limit.
But of these anon."
Gregory Nazianzen, Oration 16, Section 9, NPNF Series 2, Vol 7
"It is a sad thing to let the Manna pass and then to long for food. It is a sad thing to take a counsel too late, and to become sensible of the loss only when it is impossible to repair it
; that is, after our departure hence, and the bitter closing of the acts of each man's life, and the punishment of sinners, and the glory of the purified. Therefore do not delay in coming to grace, but hasten, lest the robber outstrip you, lest the adulterer pass you by, lest the insatiate be satisfied before you, lest the murderer seize the blessing first, or the publican or the fornicator, or any of these violent ones who take the Kingdom of heaven by force."
Gregory Nazianzen, Oration 40, On Holy Baptism, Section 24, NPNF Series 2, Vol 7
"For I know a cleansing fire which Christ came to send upon the earth, and He Himself is anagogically called a Fire. This Fire takes away whatsoever is material and of evil habit; and this He desires to kindle with all speed, for He longs for speed in doing us good, since He gives us even coals of fire to help us. I know also a fire which is not cleansing, but avenging; either that fire of Sodom which He pours down on all sinners, mingled with brimstone and storms, or that which is prepared for the Devil and his Angels or that which proceeds from the face of the Lord, and shall burn up his enemies round about; and one even more fearful still than these, the unquenchable fire which is ranged with the worm that dieth not but is eternal for the wicked.
For all these belong to the destroying power; though some may prefer even in this place to take a more merciful view of this fire, worthily of Him That chastises."
Gregory Nazianzen, Oration 40, On Holy Baptism, Section 36, NPNF Series 2, Vol 7http://web.archive.org/web/20010619045823/www.geocities.com/r_grant_jones/Rick/supplement.htm