How to Own Heretics with Facts and Logic
1200 years ago, some dudes had an argument.
by Abby Roberts

No new publications, but you’re still welcome to purchase Lady Churchill’s Rosebud Wristlet No. 51, which includes my story “A Grumble of Goddesses.” Work on the project known as Monk WIP continues, with my manuscript sitting at more than 70,000 words ish. I overhauled my plot in March, so I already know that not everything I’ve written will be kept. But yay, words.
Monk WIP research always takes me down neat rabbit holes, the fruits of which I like to foist on my captive audience of newsletter subscribers. Today we’re learning about the dialectical method, the art of arriving at truth through logical argumentation, which medieval scholars used to reach new conclusions as well as to own heretics and make them cry.
The Grand Alcuin of York
The project known as Monk WIP is, surprisingly, about monks, and monks often tend to be religious. Since Monk WIP is set in ninth century Ireland, my monks belong to the Roman Catholic or Latin Church, the Christian community that previously used Latin in the liturgy and looks to the Roman hierarchy for leadership. In Monk WIP, I want to capture the intellectualism and creativity of medieval Christianity, moving away from ye olde tropes of superstition and barbarism towards a portrayal that obviously won’t be completely accurate but will, hopefully, be less wrong. To this end, I’ve been researching 1) medieval scholarship and education, including the use of dialectic and 2) the role of women in the Latin Church, among other things.
Good news: I found a primary source from my period, the early ninth century, that deals with both of these things! It’s a letter from the scholar Alcuin to an unnamed noblewoman, advising her on handling the adoptionist heresy.
Bad news: the only version of the letter available online is in a digitized copy of an eleventy gajillion page German tome from like 1870.
Good news again: the letter isn’t in German! It’s in Latin! I sort of read Latin!
Bad news again: I only sort of read Latin.
So, armed with my community college Latin, I brute force translated a work by one of the most prominent Latin scholars of the eighth and ninth centuries.
Alcuin was an Anglo-Saxon scholar born in York around 700 and something. He received a clerical or monastic education, but it’s not clear if he ever lived under a monastic rule or held an ecclesiastic role higher than deacon before he was appointed abbot of the monastery of Saint Martin of Tours towards the end of his life. Regardless, Alcuin was a devout Christian, something that’s clear in his surviving letters and other writings. In the late eighth century, he was recruited by Charles the Great a.k.a. Charlemagne to lead his educational program because medieval rulers did, in fact, think education was good and worth investing in. Even warrior kings who enjoyed booze, boiled meat, earthy humor, and lounging nekkid in their hot tubs, like Charlemagne (see Einhard’s Life of Charlemagne).
As Charlemagne’s education czar, it was Alcuin’s job to fight heresy. This was a society that considered a kind of Christian theology to be fundamentally true, in the way we modern folks accept scientific laws to be fundamentally true. An eighth or ninth century Christian scholar wouldn’t have thought heresy to be merely a difference of opinion but something as dangerous as climate change denialism or vaccine disinformation is to us—if not more so, since a climatologist or epidemiologist probably wouldn’t say a person’s soul is endangered by their rejection of the scientific consensus, regardless of whatever harmful actions may be motivated by their beliefs. Also, a major source of Charlemagne’s legitimacy as a ruler was his claim to be a Christian king. He had to enforce Christian orthodoxy.
So, alarms went off in Aachen when some punk ass bishops from northern Spain started spouting the theologically nonstandard idea that Christ didn’t have two natures, human and divine, but had merely “adopted” a human body. The Latin term, ‘adoptivus,’ superficially recalled fourth- and fifth-century disputes about the nature of Christ, although the form of adoptionism preached by the Spanish bishops was very different from the early adoptionist heresies. Still, a heresy is a heresy. What are Charlie and Al to do?
Send in the Inquisition, right? After all, this is the peak of the DARK AGES, the height of religious bigotry and intolerance. I’ve seen documentaries like Netflix’s Castlevania and Monty Python’s Flying Circus.
Actually, no. Religiously-motivated bigotry and violence did exist in the eighth and ninth centuries—at this time, the Roman/Byzantine Empire was recovering between waves of iconoclasm, a conflict over the use of religious images. The Empire was also institutionally antisemitic and periodically cracked down on minority Christian communities deemed heretical. Charlemagne, a warrior king whose legitimacy rested on his being anointed by the pope, wasn’t immune to the lure of religious violence. However, when Charlemagne tried to force the polytheist Saxons to convert, Alcuin talked him out of it, arguing that genuine belief could not be compelled at swordpoint. Charlemagne, his predecessors, and his successors also enjoyed periods of good relations with Muslim rulers and promoted Jews such as the diplomat Isaac to high positions at court.
I’m also not sure Charlemagne could’ve persecuted the adoptionists if he wanted to. Persecutions aren’t wished into existence. Someone needs to make sure the angry mob gathers at the right time and place, and someone needs to hand out torches and pitchforks. I’m being flippant, but my very serious point is that targeted violence against certain members of a population requires planning, resources, and a monopoly on force, things best provided by the state. But the Carolingian state was a fragile thing, held together by vibes and the individual abilities of its rulers. The Roman Empire had the institutional strength to survive periods of weak or divided rule, but Carolingian control survived only as long as emperors were personally powerful enough to defeat or subdue rivals. It might have looked bad if the Christian emperor anointed by the pope had started executing bishops, maybe even bad enough to crack the coalition of secular and ecclesiastical lords that Charlemagne counted on for support. Besides, Charlemagne had plenty of external enemies, and a persecution would soak up people and resources required to deal with them.
Instead, Alcuin is going to defeat the adoptionists in the marketplace of ideas. He’s going to own the heretics with facts and logic.
Alcuin vs. the Adoptionists
Felix of Urgell, one of the big names in adoptionism, gets summoned to Charlemagne’s court at Aachen, modern Germany. This is at least the second time Felix got in trouble. Several years previously, he’d been summoned to Regensburg to debate Bishop Paulinus of Aquileia. Apparently, Paulinus didn’t do a good job, because Felix promptly returned to his home in northern Iberia and continued spreading heresy. He was a repeat offender.
It’s not clear how willingly Felix goes to Aachen. Does he decide to play along in hope of receiving more lenient treatment? Or does Charlemagne make him an offer he can’t refuse? Personally, I don’t think it was ever likely that Charlemagne’s favorite scholar would be allowed to lose a debate in Charlemagne’s own court. Too much was at stake.
But there are shades between a totally free debate and a farcical kangaroo court. Alcuin had to put in an effort to seem knowledgeable, to convince others that he was educated and orthodox. It would look bad in front of the attendant bishops if the leading intellectual at Charlemagne’s court seemed to phone it in. We know, from Alcuin’s hagiographers and his own writings, that Alcuin prepared extensively for the debate, researching past adoptionist arguments as well as Felix’s techniques. A surviving translation of the Acts of the Council of Ephesus shows sections dealing with past adoptionist controversies that were marked for copying by either Alcuin or his assistant. Felix, an experienced debater himself, was likewise permitted to bring his own research materials. And thanks to the letter mentioned above, we have some idea of how the debate played out.
It resembled the classroom exercises used to teach students in monastic schools. First, the interrogator asked a question, expecting to elicit a yes or no response. The opponent was allowed to present arguments supporting their answer. The interrogator asked another question that logically followed from the opponent’s response, allowed the opponent to reply, and so on. At some point, the roles switched, so the former opponent asked the questions and the former interrogator responded. The intent was to use one’s knowledge of Aristotelian logic, Christian scripture, and the writings of the Church Fathers to construct a chain of questions that backed your opponent into a logical corner, forcing them to admit defeat. According to Alcuin’s hagiographer, Alcuin and Felix debated in the presences of Charlemagne and various bishops for six days, until Alcuin finally quoted an argument from a letter of Cyril of Alexandria that Felix wasn’t familiar with. Felix, upon seeing manuscript proof of the letter, burst into tears and recanted. Heretics owned.
Alcuin’s letter to the noblewoman includes only thirteen questions, not enough ammo for six days of arguing. But the questions are likely similar to those Alcuin asked during his interrogation of Felix:
Interrogandum est, dum Dei filius iuxta catholicam fidem verus est filius virginis, quomodo filius virginis non sit verus filius Dei? Aut si filius virginis adoptivus est Dei patris, consequens esse videtur illa absurditas, ut adoptivus sit Dei filius virginis filius. Ergo si filius Dei vere est filius virginis, etiam filius virginis vere filius est Dei et non habet locum in utralibet generatione adoptionis nomen.
It must be asked, provided that by the Catholic faith, the true Son of God is the son of a virgin, how could the son of the virgin not be the true Son of God? Or if the son of the virgin has been adopted by God the Father, it is consequently seen to be nonsense that the son of the virgin could be the adopted Son of God. Therefore, if the Son of God truly is the son of the virgin, likewise, the son of the virgin truly is the Son of God, and either way, the word “adoption” has no place in the construction.
Because Alcuin is sharing practical tips, not writing a treatise, he leaves some parts of his argument to implication, assuming his addressee will figure them out. Moreover, Alcuin’s argument rests on assumptions that the modern reader might not share, as Alcuin’s addressee would have. But what Alcuin intends to do is point out what he perceives as logical flaws in the adoptionist argument.
According to Catholic teaching, which Felix and other adoptionists would have accepted, the prophets of the Hebrew Bible foretold that the messiah, the Son of God, would be the son of a virgin. The Latin phrase ‘verus filius,’ which I’ve translated as ‘true son,’ is contrasted with ‘adoptivus’—in Alcuin’s understanding of lineage and descent, a son must be begotten by his father, so an adopted son, by definition, cannot be a ‘true’ son. If the Son of God is the son of a virgin, the son of a virgin must be the true Son of God. If A=B, then B=A. This is an argument based on elementary logic, if one accepts the theological assumptions Alcuin’s premise is based on.
Moreover, Catholic teaching holds that the Virgin Mary conceived Jesus Christ miraculously, without having intercourse with a man. So, if Jesus is the son of a virgin, and the son of a virgin is the true Son of God; therefore, Jesus is the true Son of God. If A=B, and B=C; therefore, A=C. And because Alcuin asserted that a ‘true’ son could not be an adopted son—regardless of any feelings adoptive parents and adopted children might have on the issue—Jesus could not be the adopted Son of God. Again, provided you accept the theological premises, Alcuin is making a sound logical argument of a type known as a syllogism.
We know from Alcuin’s writings that Felix’s adoptionist arguments also attempted to make use of Aristotelian syllogistic logic, which Latin-speaking medieval Europeans would have learned through Boethius’ translation of Aristotle’s Organon. But Alcuin, as we see here, found the adoptionist argument logically inconsistent, and in other writings, he castigated the inability of Felix and his colleague Elipandus to create coherent logical arguments. Given that none of the adoptionist writings have survived, we’ll have to take Alcuin’s word for it.
Ninth Century Intellectual Culture
The letter, with the rest of Alcuin’s body of work, tells us a few interesting things about early medieval intellectual culture. First of all, it existed. Many people, including me, were taught growing up that learning was somehow “out of fashion” in Europe for the 1,000 years between 450 and 1450 CE. But here’s Alcuin, with his book learning and dialectic.
Second, and more interestingly, we see that the type of knowledge that Alcuin and other Latin Christians took for granted was very different from the type of knowledge considered credible by most twenty-first century Westerners. Most modern Westerners draw primarily on a body of knowledge based on scientific observations about the physical universe. Medieval people drew primarily on written or oral cultural traditions—if not the traditions of Christianity, than those of Judaism, Islam or another religion. If their way of thinking seems naive, credulous, and irrational to us, so would ours seem to them. A time traveler in ninth century Francia would probably struggle to convince Alcuin and his contemporaries of the reality of, for example, gravity and DNA, because their medieval audience would not have access to the intervening centuries worth of scientific discoveries and theoretical developments required to make sense of these concepts. Facts, to a degree, are culturally contingent.
But within the medieval Christian system of knowledge, Alcuin’s thought was, in fact, logical. He expected logic and intellectual rigor from his opponents as well. In the excerpt quoted above, he labels his hypothetical opponent’s adoptionist arguments ‘absurditas,’ ‘nonsense,’ but, in Alcuin’s view, they are nonsensical because he can show they are illogical; he doesn’t dismiss them out of hand. In Alcuin, we don’t have a Claude Frollo-esque figure screaming “blasphemy!” and “heresy!” to shut down unfamiliar ideas. He took the time to deal with his opponent thoughtfully.
Debate is also a mild method of dealing with dissent. Felix could have simply been executed. In fact, you may be asking, what happened to Felix after his six-day ordeal? Did he go home? Was he dragged away to the dungeon? Was he burned at the stake? None of the above: he was either forced or strongly encouraged to write a statement, which survives, disavowing his adoptionist views and promising not to use the word ‘adoptivus’ again. He was not permitted to return to Urgel but was placed in the custody of the Archbishop of Lyon. But after Felix died, the archbishop found among his papers a treatise that defended his beliefs—without using the word ‘adoptionist.’ A level of pettiness I respect.
This tells us that early medieval Francia wasn’t exactly a paradise of intellectual freedom, but it was also not a nightmarish dystopia of inquisitors and thought crimes.
Finally, we learn at least one more thing from Alcuin’s letter, or, more accurately, the person it was written to. Alcuin addresses her only as “a most beloved daughter in Christ,”1 but she is thought to be Gundrada, a cousin of Charlemagne. Traditionally, Gundrada was thought to be a nun, but there’s no evidence that is the case. She is referred to in other writings as a “noble virgin” and a “bride of God,” but she is also said to have lived at the palace, not in a monastery. So perhaps Gundrada was a nun in residence at Aachen or perhaps she made less formal vows. At any rate, she seems to have held some sort of teaching role in the palace.
Regardless of whether Alcuin’s addressee was Gundrada, she was a very educated woman. Alcuin praises her as “most skilled in the fine points of dialectics”2 and urges her to apply “scientific principles”3 from her scholarship when debating with adoptionists. So, if the evidence of Alcuin addressing his how-to-debate-heretics guide to this woman was not enough, we have him urging her to apply her own education when engaging in theological debates. At no point does Alcuin insinuate that women may be unsuited to such activities or advise her to leave them to men. At no point does he talk down to her. In fact, as the lower-ranking party, Alcuin butters her up. So, we see that eighth- and ninth-century Francia was home to a thriving intellectual culture, one based just as much on Classical philosophy as Christian writings and scripture, and one that played host to an active debate sene—which women, at least those of high rank, could participate in too.
Resources and References
Alcuin. “Epistola 144.” Monumenta Alcuiniana, edited by W. Wattenbach and E. Dümmler, Berlin, 1873. pp. 547-552. HathiTrust.
Carlson, Laura M. “The Rhetoric of Heresy: Alcuin, Adoptionism, and the Art of Language.” The Heroic Age: A Journal of Early Medieval Northwestern Europe, no. 16, 2015.
Nelson, Jinty. “Alcuin’s Letters Sent from Francia to Anglo-Saxon and Frankish Women Religious.” The Land of the English Kin: Studies in Wessex and Anglo-Saxon England in Honour of Professor Barbara Yorke, edited by Alex Langlands and Ryan Lavelle, Brill, 2020, pp. 355-372.
O’Daly, Irene, Irene van Renswoude, and Mariken Teeuwen. The Art of Reasoning in Medieval Manuscripts. December 2020.
van Renswoude, Irene. “The Art of Disputation: Dialogue, Dialectic and Debate around 800.” Early Medieval Europe, vol. 25, no. 1, February 2017, pp. 38-53. Wiley Online Library.
What Am I Doing?
Not much. Writing for once. After finishing Ada Palmer’s nonfiction Inventing the Renaissance on audiobook, I started her science fiction novel Too Like the Lightning. Highly recommended.
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