Heresy

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Heresy is a belief held to deviate from an established orthodoxy — and, in the strict sense, deviation by someone inside the community rather than outside it. The heretic is not the unbeliever or the follower of another faith; the heretic is one of us who has gone wrong. That is what makes the charge sharp, and what made it, for much of Christian history, a matter of life and death. The pagan and the idolater stand outside the circle and can be argued with, converted, or ignored. The heretic stands inside it, holding the same scriptures and claiming the same Lord, and turns the community’s own language against the line it has drawn. A boundary violated from within wounds differently than a boundary approached from without, and the literature of heresy is, before anything else, the record of that particular wound.

The word descends from the Greek hairesis, which began without the sting it later carried. It meant a choosing — and, by extension, a school of thought or a philosophical sect, the way one might speak of the Stoics or the Epicureans as a hairesis. The historian Josephus uses it without reproach for the Pharisees, the Sadducees, and the Essenes; the Acts of the Apostles can call the followers of Jesus a hairesis in exactly that descriptive sense, a party within the Judaism of its day. To belong to a hairesis was to have made a choice among available teachings — no scandal in a world of competing schools. Early Christian writers turned the neutral word into an accusation: to choose one’s own doctrine, rather than receive the apostolic teaching whole, was already the error. The very act of selection — picking, weighing, preferring — became the sin the word now names. By the second century a body of literature existed for the sole purpose of cataloguing and refuting such choices. Its authors — Irenaeus, Hippolytus, Tertullian, Epiphanius — are known to scholarship as the heresiologists, and their works are arranged as lists: this group taught that, that group taught this, and here is why each is wrong. The genre itself — patristic heresiology — became one of the most durable inventions of the early Church, a machine for fixing the apostolic faith by mapping in exhaustive detail everything held to fall outside it.

What the heresiologists were doing was not merely description but the manufacture of a concept. The idea of heresy as a single, coherent thing — a contagion with a genealogy, traceable like a family tree to a founding deceiver — had to be built before it could be deployed. Irenaeus of Lyon, writing around 180, gave the program its founding work and its method: trace every error back to Simon Magus, the sorcerer of Acts, and arrange the rival teachers as a single corrupt lineage descending from a common root. Truth was original and singular; error was always later, derivative, parasitic. The heresiologist therefore wrote as physician and genealogist at once, and Epiphanius of Salamis made the medical metaphor literal in his Panarion — the “medicine chest” — where eighty heresies are cataloged as so many venoms, each with its prescribed antidote. The form rewarded comprehensiveness, which is the first of its paradoxes: to refute a system, the author first had to summarize it, and so the apparatus built to destroy these teachings became the vessel that preserved them.

Those lists are the trap the modern historian works around. For most of the groups they describe — the followers of Valentinus and the other currents later filed under “Gnosticism” above all — the heresiologists’ refutations were for centuries the only surviving witness, so that the heretics were known only in the words of the people determined to destroy them. Gnosticism is the supreme case: a loose family of second- and third-century movements that knew the cosmos as the flawed work of a lesser power and salvation as the awakening of a divine spark through gnosis, and whose teachers reached the record almost entirely as entries in hostile catalogs. When the Coptic codices buried near Nag Hammadi came to light in December 1945, several of these systems could at last be read in their adherents’ own words, and the comparison proved uneven: sometimes the Fathers had paraphrased with care, sometimes they had flattened distinct groups into one or sharpened a doctrine into absurdity. The very name “Gnosticism” turned out to be largely an artifact of heresiology, assembled by the refuters and inherited by the scholars who studied them — a reminder that to be known only through one’s foes is to risk not existing, in the record, in any other shape than the one they chose. Gnosticism is not a synonym for heresy; it is the clearest single instance of what heresy does to the memory of the condemned.

The deeper point, pressed hard in twentieth-century scholarship, is that orthodoxy and heresy were not fixed positions with deviation measured against them. In 1934 the German lexicographer Walter Bauer (1877–1960) published Rechtgläubigkeit und Ketzerei im ältesten Christentum — “Orthodoxy and Heresy in Earliest Christianity” — and argued that in region after region the form of Christianity later called heretical had come first. At Edessa the earliest Christian figures were Marcion, Bardaisan, and Mani; in Egypt a gnostic Christianity appears to have been dominant before the church of the bishops took hold. On Bauer’s reading, “orthodoxy” was not the original deposit from which the heretics fell away but the party that eventually won — frequently the church of Rome — and then named its rivals afterward, projecting its own victory backward as though it had always been the standard. Heresy, on this account, is less a stable thing than a relation: the label the victorious doctrine applies to the losers, retrojected as if it had always been the deviation. The thesis did not go unchallenged — H. E. W. Turner answered it in 1954, insisting on a genuine, if untidy, continuity of apostolic teaching — but it reset the terms of the question, and a later generation, Bart D. Ehrman among them, made its central move a commonplace: the winners write the history, and in writing it they make the contest look as though there had never been one.

What the accused believed, they did not experience as deviation. They held themselves to possess the true teaching and regarded the emerging mainstream as the corruption; the line ran both ways, and only one side kept the power to enforce it. From inside a condemned community the heresiologist’s verdict looks exactly inverted — it is the catholic party that has innovated, compromised, mistaken the demiurge for the Father, or buried the spirit under law and hierarchy. The history of doctrine, read from the losing side, is the history of a usurpation. This is not a relativist’s flourish but a structural feature of the material: every surviving heresiology assumes a vantage, and the vantage is always the one that prevailed. The accused had vantages too; the difference is that theirs were burned.

Out of that enforcement grew the machinery the word now summons. It began with the formula and the curse. Councils of bishops defined the faith in precise language and attached to the definitions an anathema — a solemn handing-over of the dissenter to separation from the body of the faithful — so that to hold the condemned proposition was, by the council’s own act, to place oneself outside the Church. From the curse followed excommunication, the formal severing of a member from the community’s rites and fellowship. And once the empire had made the catholic faith the law of the state — the Theodosian legislation of the late fourth century gave heresy the standing of a public crime — the curse acquired a sword. Around 385 the Spanish bishop Priscillian of Avila, condemned for a rigorist asceticism his rivals read as heresy, was beheaded at Trier under the usurper emperor Magnus Maximus, the first Christian put to death for his beliefs by Christian authority — an outcome that Martin of Tours and Ambrose of Milan denounced, refusing communion with the bishops who had sought it. The instinct to draw the line and the instinct to recoil from killing over it were present together from the start. In the medieval West the apparatus hardened into the inquisition, the standing tribunal charged with detecting and correcting heretical error, and behind it stood the stake — the secular arm executing the sentence the Church declined to carry out with its own hands. The philosopher Giordano Bruno, an ex-Dominican who taught an infinite, animate universe of innumerable worlds, was burned by the Roman Inquisition in the Campo de’ Fiori in February 1600; the Reformation gave the machinery to both sides at once, and the physician Michael Servetus, who denied the Trinity, was burned at Geneva in 1553 under a Protestant magistracy. Heresy is the one religious category whose full meaning includes a method of death.

The medieval centuries also show the relation at its rawest, because there the condemned currents are visible as organized communities and not merely as names in a list. The Cathars of Languedoc and Lombardy and the Bogomils of the Balkans professed a dualist Christianity — two principles, a good God and an evil maker of the material world — and drew upon themselves the Albigensian Crusade and the inquisitorial registers that are now, once again, nearly the whole surviving record of what they taught. The Heresy of the Free Spirit, a charge leveled at certain mystics held to claim a perfection that placed them beyond sin and law, may have been in part a construction of the inquisitors who hunted it, a heresy assembled from confessions extracted under examination. Here the historiographical problem turns practical and ethical: when nearly everything known about a movement comes from the tribunal that destroyed it, the category “heresy” is not merely a label applied after the fact but the very lens through which the movement survives at all — and the question of what these people actually believed cannot be cleanly separated from the question of what their persecutors needed them to have believed.

The category did not stay confined to Christianity. Wherever a tradition fixes a boundary around right belief, the figure of the one who crossed it from within takes shape on the far side of the line — and the vocabularies that name him are worth setting beside the Christian one, not to merge them but to see the same labor done in different grammars. Islamic thought developed the concept of bid’a, “innovation” — a newly introduced matter in religion without precedent in the Qur’an or the practice of the Prophet, contrasted with the sunna and, in the strict view, condemned as a straying from the path. Beside it stood zandaqa: the zindiq, a term of Persian origin meaning at first a Manichaean dualist and then, more loosely, a freethinker or unbeliever within the community, was hunted in the early Abbasid mihna, an inquisition begun under the caliph al-Mahdi around 780 to root out crypto-dualism. The further act of takfir — one Muslim declaring another to be kafir, an unbeliever, and so expelling him from the community of faith — is the Islamic counterpart to the anathema, a pronouncement that moves a man from inside the circle to outside it by speech alone. Rabbinic Judaism named those who set themselves apart from the community’s teaching the minim — literally “kinds” or “species,” the sectarians — and the apikoros, the term carrying the name of Epicurus and marking the one who denies divine providence and the authority of the sages. The Birkat ha-minim, the benediction against heretics woven into the daily prayer, made the boundary part of the liturgy itself, recited rather than merely decreed. Maimonides later fixed a list of required beliefs — the Thirteen Principles — and thereby made it possible to say with precision who had stepped outside them. And the herem, the ban, severed the offender from the community as the anathema severed the Christian: the herem pronounced over Baruch Spinoza by the Portuguese congregation of Amsterdam on 27 July 1656 — for “abominable heresies” the document does not trouble to specify — remains the most famous instance of a tradition cutting loose one of its own.

The concept under the historian’s lens

That the notion of heresy is itself a made thing, with a datable origin and an author, is the central finding of the modern study of the subject, and it has its own critical literature. Alain Le Boulluec’s La notion d’hérésie dans la littérature grecque, IIᵉ–IIIᵉ siècles (Études Augustiniennes, 1985; English translation, The Notion of Heresy in Greek Literature in the Second and Third Centuries, Oxford University Press, 2022) locates the decisive invention in Justin Martyr and its consolidation in Irenaeus: the representation of heresy as a single diabolical lineage was assembled by fusing the Greek doxographic habit of sorting philosophers into rival schools with the apocalyptic theme of a conspiracy of the deceiver — a construction, not a report. Walter Bauer’s Rechtgläubigkeit und Ketzerei im ältesten Christentum (Tübingen: Mohr, 1934; 2nd ed. ed. Georg Strecker, 1964) is the foundational dismantling of the orthodoxy-came-first assumption; the standard English edition, Orthodoxy and Heresy in Earliest Christianity (Fortress Press, 1971), edited by Robert A. Kraft and Gerhard Krodel, carried it into Anglophone scholarship, where H. E. W. Turner’s The Pattern of Christian Truth (Mowbray, 1954) had already supplied the major rejoinder. The way the category “Gnosticism” was manufactured out of heresiology and then inherited by the historians is anatomized in Karen L. King’s What Is Gnosticism? (Belknap Press of Harvard University Press, 2003) and in David Brakke’s The Gnostics (Harvard University Press, 2010), which retires the umbrella term while showing how “proto-orthodoxy” is itself a back-formation imposed on a far more fluid scene. The popular dissemination of Bauer’s approach belongs to Bart D. Ehrman’s Lost Christianities (Oxford University Press, 2003). For the texture of the medieval enforcement, the foundational nineteenth-century syntheses remain in reach — Henry Charles Lea’s A History of the Inquisition of the Middle Ages, 3 vols. (New York, 1888), and Charles Schmidt’s Histoire et doctrine de la secte des Cathares ou Albigeois, 2 vols. (Paris–Geneva, 1848–1849) — while the indispensable demonstration that the refuters preserved what they meant to bury is G. R. S. Mead’s reading of the Gnostic record through the heresiologists in Fragments of a Faith Forgotten (1900; 2nd ed. 1906), whose chapter on “the Gnosis according to its foes” names the predicament that all later scholarship has had to work around.

To call something a heresy is to make two claims at once: that a doctrine is wrong, and that the one who holds it ought to have known better, because he belongs. The second claim is the load-bearing one. It is why the heretic is hated more than the infidel and why the apparatus built against him — the council, the anathema, the tribunal, the fire — was built by the very community he refused to leave. The drawing of the line falls after the dispute that called for it, not before; the orthodoxy that a heresy is measured against is, more often than the catalogs admit, the residue of an argument that another party might have won — and did win, here and there, for a while, in places where the survivors were the ones the lists would later condemn.

→ In the library: Mead — Fragments of a Faith Forgotten: The Gnosis According to its Foes

→ Related: Gnosis · Gnosticism · Patristic Heresiology · Excommunication · Idolatry · Neoplatonism · Catharism · Bogomilism · Heresy Of The Free Spirit · Christianity · Eastern Orthodox Christianity · Dualism