The question behind the question
Ask an Orthodox priest whether Christian doctrine develops and you will usually get a hesitation before the answer. The hesitation is not evasion. It is the recognition that the word carries two quite different meanings, and that agreeing or disagreeing too quickly will mislead whoever asked.
One instinct governs the Orthodox side of this conversation, and it is worth stating before anything else. The faith is received, not composed. St Jude writes of "the faith which was once for all delivered to the saints" (Jude 3, RSV), and Orthodoxy has taken that phrase with great seriousness: bishops and councils are stewards of something already given, not a standing committee empowered to improve it. Whatever else is true, the Church does not hold that she may teach in the twenty-first century what she could not have taught in the second.
But the Church plainly says things now that nobody said in the year 60. The Nicene Creed uses a Greek philosophical term that is not in Scripture. A council defended a title for the Virgin Mary that Scripture does not use in that form. Something has happened between then and now, and pretending otherwise would be dishonest. The question is what.
Two things the word can mean
When a Roman Catholic theologian says doctrine develops, he usually means that the Church's understanding of a revelation given once can genuinely unfold over time, so that what was implicit becomes explicit and may be defined as binding. When an Orthodox theologian denies that doctrine develops, he usually means that the content of the faith cannot be added to, and that the Church's task is to state the same faith in whatever words each crisis requires. Stated that way, the two positions overlap considerably and disagree about something narrow and important.
Fr. Seraphim Rose made a methodological observation in the middle of an entirely different argument, about creation and evolution, and it applies here exactly. His complaint was that two parties can spend years exchanging fire while using a shared word for two different things, so that neither side ever hears what the other is claiming. Anyone entering the argument about doctrinal development should establish first which of the two questions is being asked, because the answers run in opposite directions.
Many of the arguments between 'evolutionists' and 'anti-evolutionists' are useless, for one basic reason: they are usually not arguing about the same thing.
Fr. Seraphim Rose, letter to Dr Alexander Kalomiros, in Genesis, Creation and Early Man, Part Two, "A Clear Definition" (St. Herman Press)
St Vincent of Lerins and his canon
The classic text on this question in the Christian tradition was written around 434 by a monk of the island monastery of Lerins, off the coast of Provence, under the pen-name Peregrinus. His short book is usually called the Commonitory, and he wrote it to answer a practical problem: when a new teaching appears and its defenders quote Scripture for it, how does an ordinary Christian tell truth from novelty?
His answer, in the second chapter, is the sentence that has been quoted ever since. Christians should hold "that faith which has been believed everywhere, always, by all", and the rule is observed by following "universality, antiquity, consent" (Commonitory ch. 2, in the translation of C. A. Heurtley). Universality means what the Church confesses across the world, antiquity what was held by the fathers before us, consent what the great majority of them agreed in teaching.
It is a better rule than it is sometimes made to sound, and also a harder one to use. Applied with a ruler, it would exclude a good deal that every Christian accepts, since almost nothing has been taught in identical words by literally everyone from the beginning. Vincent knew this. Most of the Commonitory is devoted to the cases where the rule is difficult, and it is precisely because he knew it that he wrote the chapter that follows.
Vincent's own answer: growth, not alteration
The twenty-third chapter of the Commonitory is headed, in Heurtley's rendering, "On Development in Religious Knowledge", and it is not what a reader expecting a flat denial of change would predict. Vincent asks whether there is then no progress in the Church of Christ, and answers that there is, and that it should be very great. What he refuses is the substitution of one thing for another. In his words: "Progress requires that the subject be enlarged in itself, alteration, that it be transformed into something else."
His image is a body. A child grows into an adult and acquires size, strength and proportion, yet no new limbs appear; the joints of the grown man were already framed in the infant. So the Church may understand more, explain better, and defend more precisely, provided it is the same teaching "in the same doctrine, in the same sense, and in the same meaning". That last phrase, in eodem sensu eademque sententia, is the load-bearing one, and it is the test Orthodoxy still applies.
So the Orthodox instinct is not hostility to growth as such, and it is worth noticing that the tradition's most quoted defender of antiquity was the one who said so. What Vincent rules out is transformation dressed as maturity. What he permits is a Church that understands its own confession more deeply, states it more exactly, and defends it more capably, because someone has denied it and the denial has to be answered.
New words in the service of an old faith
Take homoousios, the word at the centre of Nicaea in 325. It is not a biblical term. Worse, later writers report that it had been rejected at a synod at Antioch in the 260s, in connection with the condemnation of Paul of Samosata, so the fathers at Nicaea adopted a word with an awkward history. St Athanasius spent a treatise defending the use of a non-scriptural term, arguing that the word was needed because Arius and his supporters could sign every scriptural formula while meaning by it something the Church did not mean.
That is the pattern. The word added nothing to the faith; it closed a door that had been propped open. Christians had worshipped Christ as God for three centuries without the term, and the term was coined so that they could go on doing exactly what they had been doing without being told that it meant something else. New vocabulary is a defensive measure, and the Church has generally adopted it reluctantly.
Theotokos works the same way. The title was in use in Greek Christian prayer well before Ephesus defined it in 431; the ancient prayer known in English as "Beneath thy compassion" survives on a Greek papyrus usually dated to the third or fourth century, though the dating has been argued over. The council did not invent the word. It refused to let the word be taken away, because what the word protects is a statement about Christ: the one born of Mary is the eternal Son, and not a man associated with him.
Newman's proposal, taken seriously
John Henry Newman published An Essay on the Development of Christian Doctrine in 1845, as he was leaving the Church of England for Rome. The book deserves better than the caricature it often receives, and an Orthodox reader who has not read it is arguing with a rumour. Newman was facing a genuine difficulty with complete honesty: the Church of the fourth century said things the Church of the first century had not said in those words, and appeals to antiquity alone did not seem to him to account for it.
His proposal was that a living idea in a living community behaves like a living thing. It is turned over, tested, applied to new circumstances, and what was implicit in it becomes explicit. He knew perfectly well that this could be used to justify anything, so he offered seven notes for distinguishing a true development from a corruption — among them preservation of type, continuity of principles, power of assimilation, and conservative action upon its past. The care is real. Newman was not looking for a licence.
He also drew, pointedly, on Vincent of Lerins. Both men use the image of bodily growth. That is the measure of how close the two accounts can stand, and it makes the remaining distance worth identifying accurately rather than rhetorically.
Why Orthodoxy hesitates
The first hesitation is about where the burden of proof sits. On a developmental account, a teaching can be justified by showing that it follows from principles the Church has always held, even if no one taught it for many centuries. Orthodoxy wants something more stubborn: the witness of the Church's actual prayer, preaching and practice. A doctrine that cannot be found in what Christians were doing on their knees is, on Orthodox terms, unproven however elegant the line of inference.
A second hesitation concerns the early Church. If doctrine unfolds, then believers in the second century possessed the faith in a less complete form than believers today, and Orthodoxy is reluctant to say that. The martyrs of Lyons in 177 had the whole faith. What they lacked was not truth but vocabulary, and vocabulary was only needed later because the truth was later attacked.
The third hesitation is historical and should be stated without heat. Newman's theory was framed in part to account for teachings that Orthodoxy does not accept — among them the universal jurisdiction and the personal infallibility of the Bishop of Rome, defined in 1870, and the Immaculate Conception, defined in 1854. Orthodox Christians do not hold those doctrines and have said so for centuries. The theory of development is not the reason for that disagreement, but it is the framework that made the disagreement easier to describe.
Orthodox theologians are not entirely of one mind here. Some have argued that the gap between a carefully stated theory of development and the Orthodox account of unfolding expression is narrower than the vocabulary suggests, while others regard the whole category as foreign. Anyone who tells you that the Orthodox tradition speaks with one voice on this particular question is tidying up.
Guarding is not the same as repeating
There is a way of holding all this that is faithful in form and dead in substance: to keep the formulas and lose the thing the formulas were made to protect. Orthodoxy is not immune from it. Fr. Seraphim Rose, writing in the 1970s about a narrowness he saw growing among converts and Western-born Orthodox, thought this the real danger rather than laxity.
the chief danger is something much deeper—the loss of the savor of Orthodoxy
Fr. Seraphim Rose, quoted in Hieromonk Damascene, Father Seraphim Rose: His Life and Works, ch. 63 "Super-Correctness" (St. Herman Press, 2003)
Where this leaves an enquirer
For a Protestant reader, much of this will feel familiar from an unexpected direction. The Reformers' appeal to antiquity, the suspicion of teachings that appear late without early witnesses, the instinct that the Church is accountable to something she did not invent — these are Orthodox instincts too, and the overlap is not accidental. Where Orthodoxy differs is in locating the guarded thing in the continuous life of a visible Church rather than in the text alone, and that difference is real and should not be smoothed over.
Preservation, understood properly, is not a filing system. It is closer to what a family does with a language: the grammar does not change, the vocabulary grows as it must, and the whole thing dies the moment nobody speaks it at home. The councils coined words because the faith was being spoken, and was being contradicted, by people who cared enormously. A tradition that had stopped caring would not have needed homoousios at all.
Which is why the last word here should be about temperature rather than precision. Fr. Seraphim spent his final years defending Blessed Augustine of Hippo, whose errors on grace and predestination he did not defend at all, against Orthodox writers of his own day who wanted the man himself struck off the list of fathers. Writing to a priest in June 1981, he explained where his own fear lay.
If you have read this far and think the Orthodox answer too conservative, that is a reasonable place to stand and we are not going to argue you out of it in an article. Come and see what a faith that believes itself unchanged actually looks like in a room on a Sunday morning. Judgements of that kind are better made from inside a building than from outside one.
I myself fear the cold hearts of the 'intellectually correct' much more than any errors you might find in Augustine.
Fr. Seraphim Rose, letter of 26 June 1981, quoted in Hieromonk Damascene, Father Seraphim Rose: His Life and Works, ch. 86 "Orthodoxy of the Heart" (St. Herman Press, 2003)