The second of the four questions Harnack sets himself on his second page is whether he has overestimated Marcion’s significance “for the development of Christianity into the Catholic Church.” The canon side of that question has already been dealt with. What remains is the institution.
Two claims are available and they are not the same. One is that Marcion created Catholicism. The other is that the Great Church took much of its institutional and polemical shape through sustained opposition to him. The first is too strong and Harnack does not quite make it. The second is historically serious, and it is what the evidence in this pamphlet actually supports.
The Evidence
Begin with the evidence, which is in a long footnote that starts on his twentieth page and runs over onto the twenty-first. Harnack offers four observations, and their force is cumulative.
First, volume. “Compared with the army of ecclesiastical opponents of Marcion, from Justin to Esnik, the number of the combatants who wrote against the individual Gnostic sects is vanishingly small.” Whatever the second and third centuries thought they were fighting, they wrote about it at a length that can be counted.
Second, drift. “Irenaeus intends in his main work above all to oppose the Valentinians, but slides involuntarily into opposing Marcion.” That is a nice observation and it is checkable in a way the others are not. A writer who keeps turning toward an opponent he did not sit down to refute is telling you what actually presses on him.
Third, testimony from outside. “Celsus, once one sees through his presentation, unquestionably attests that the Marcionite church was the real and only rival of the great Church in his time.” This is Harnack’s judgment about what a hostile pagan reader implies, not a sentence Celsus wrote, and “the real and only rival” is a stronger formulation than a modern historian would reach for. It is his reading, and it should be labelled as his.
Fourth, classification. “Justin presents to his heathen addressees Simon Magus, Menander and Marcion as the founders of pseudo-Christianity, and designates all remaining heretics as οἱ ἀπὸ τούτων ὁρμώμενοι”, those who take their start from these. When a second-century apologist explains Christian deviance to outsiders, Marcion is one of the three names he needs, and the rest are derivative.
What is striking is that Harnack draws this list while revising his own earlier position downward, and in the same footnote. Someone had objected that he now underestimates Gnosticism. He concedes the change: “I have in fact somewhat altered my judgment at this point.” But he draws a distinction that has worn well. “About the intellectual significance of Gnosticism I think no differently than before; but the factual significance of this phenomenon, in so far as it provoked a struggle and reactions, was not so enormous, once one separates Gnosticism sharply from Marcionitism.”
That is a claim about scale rather than about classification, and the second section of this afterword makes it easier to see why it holds. If “Gnosticism” was never one movement, then the polemical energy the Church spent was never spent on one opponent; and once Marcion is pulled out of the aggregate, what is left is a scatter of teachers and schools, provoking scattered replies. The concentration was on him. Harnack is not saying the Gnostic teachers were unimportant thinkers. He is saying they were not the thing that made the Church organize itself.
The Concession
Then, on his twenty-first page, he concedes the strongest point against his own case, and concedes it without qualification. “One can — I do not fail to see this — demonstrate parallels and preliminary stages, whether in the Great Church or among Gnostics, for every single point in the church-constructive and dogma-historical field that is characteristic of M.’s creation.”
Every single point. Bishops before Marcion. Rules of faith before Marcion. Public reading of apostolic writings before Marcion. Boundaries and expulsions before Marcion. There is no institutional feature of the later Church for which someone cannot produce an earlier instance.
His reply is a question rather than a rebuttal: “one must also ask whether the ‘preliminary stages’ would have led, without his intervention, to the further developments that actually took place.” That is the same counterfactual encountered over the canon, in its institutional form, and it points at the right distinction. The ingredients existed. What a crisis does to existing ingredients is accelerate them, harden them, and (this is the part that matters) make them depend on each other. Loose practices become a system when they have to answer a rival system.
And Harnack then says something about his own method that most historians would have left out. The answer to the difficult question, he writes, “depends on integrated historical impressions of which one can hardly give an account to others.” He adds: “I have won this insight quite gradually from largely buried sources, but I am of course defenceless against the obvious objection that in my long-standing and zealous preoccupation with the subject I have lost my way.”
I take that as candour rather than self-disqualification, and it is worth being clear about why. Historical causation at this scale is not the sort of thing that can be proved the way a textual variant can be proved. You cannot run the second century again without Marcion. What you can do is describe what the sources show, say what impression it leaves, and admit that the impression is doing work that evidence alone cannot do. Harnack does all three. A great many confident sentences about the origins of Catholicism rest on exactly this kind of judgment without saying so.
The Luther Comparison
The comparison he reaches for is Luther, and it needs its limits drawn. On his twenty-fourth page: “The great man in history founds an age. That M. did not do; for he was unable to prevail, however much he did, both negatively and positively, to bring the old-Catholic age into being. This age is not to be conceived without M., any more than post-Tridentine Catholicism is to be conceived without Luther.” A footnote adds that objection had been made to the parallel, that he was not the first to draw it (Neander was) and that he wastes no word on it “because both its justification and its limits are equally obvious.”
They are not quite as obvious as he says, so let me draw them. The comparison does not mean that Marcion and Luther taught anything like the same theology; they did not. It does not mean either man created the church that formed against him. And it emphatically does not mean the institutional result was what either intended: Marcion, Harnack rightly notes, “wanted to tear Christendom out of the development toward Catholicism,” and got the opposite. What the comparison does mean is that a movement can be defined by what it had to exclude: that Trent is unintelligible without the Reformation it answers, and that the old-Catholic settlement is unintelligible without the alternative it answered. The opponent forces self-definition. Structures that were customary become required. And the shape of the victor carries the shape of the fight.
Created By, or Shaped Against?
So: created by, or shaped against? Shaped against, on the evidence available, and the distinction is worth holding precisely. The Great Church existed before Marcion and would have existed without him. Bishops, rules of faith, liturgical reading, apostolic authority and communal boundaries were all in place or forming, and none of them is his invention or his gift. What opposition to him did was make them explicit, bounded and mutually reinforcing. A canon is one thing; a canon held by bishops, read under a rule of faith, and defended by a literature of heresiology is a system; and it became a system substantially in the course of answering another system. That is why the second-century Church ends up with a New Testament in which Paul stands among the other apostles rather than over them, with a rule that governs how scripture may be read, and with a category of heretic that has a founder’s name attached to it.
None of which is a grievance, and I want to be careful here, because this is the point at which a Marcionite writer is most tempted to overreach. The Church did not steal a structure. It was not invented to defeat anybody. And nothing in the historical argument reverses the verdict that was passed on Marcion; verdicts of that kind are not reversed by showing they were consequential.
What the history does is explain the furniture. It explains why the New Testament has the shape it has and why its four gospels are four. It explains why Paul, whose gospel was once the gospel for a whole church, is now one apostolic voice in a chorus. It explains why reading scripture came to be governed by a rule external to it. And it explains why, of all the second century’s dissenters, this one became the defining heretic, not because he was the strangest but because he was the nearest thing to a rival.
Which is also why the collision left marks on both sides. Paul had already told the Galatians what such a conflict looks like from inside: “when I saw that they were not walking uprightly toward the truth of the Evangelion, I said to Peter in the presence of all” (Galatians 2:12 TT). Division over the truth of the message is not a later corruption of this movement; it is in its first documents. And Paul says something odder about it to the Corinthians: “There must also be factions among you, so that those who are approved may become manifest among you” (1 Corinthians 11:13 TT). Positions become visible when they are opposed. That is a description of what happened to the Great Church in the second century, and it is a description of what happened to Marcion’s.
One footnote of intellectual history deserves a sentence. The Walter Bauer who presses Harnack so hard in these pages, arguing that Marcion was a Gnostic swept along by the currents of his age, would eleven years later publish Orthodoxy and Heresy in Earliest Christianity, a book about how the winners in such conflicts write the history. He was, in 1923, arguing the opposite of what he became known for.
The history is settled enough. What remains is the wish.