A scholarly polemic by Florus of Lyon that methodically dismantles John Scotus Eriugena's rationalistic approach to predestination, defending Augustinian theology through authoritative citations while articulating a nuanced position that affirms both divine sovereignty and human responsibility in the 9th-century Carolingian theological debate.

Historical Context and Purpose

The Liber adversus Joannem Scotum (“Book against John Scotus”) emerged from the 9th-century predestination controversy in the Carolingian Empire. This theological dispute began when the monk Gottschalk of Orbais advocated a strict double predestination theory—that God actively predestines some souls to heaven and others to hell—citing St. Augustine as his authority. This position alarmed many in the Frankish church.

Around 848–851, the Irish scholar John Scotus Eriugena wrote De Praedestinatione (On Predestination) at the request of King Charles the Bald, intervening in the heated debate sparked by Gottschalk. Eriugena opposed Gottschalk by arguing for a “single” predestination—that God predestines no one to sin or damnation, but only to grace and salvation. While Eriugena believed he was following Augustine’s authority, his approach was highly rationalistic and philosophical, with little deference to established church authority.

In response, Florus of Lyon—a deacon and learned theologian—was commissioned by the Church of Lyon in 852 to write a refutation of Eriugena’s ideas. The resulting work, Liber adversus Joannem Scotum, was intended to safeguard orthodox doctrine against what Florus and his peers saw as Eriugena’s dangerous errors, and to dissuade others from being swayed by Eriugena’s philosophical but unorthodox arguments.

Authorship: Florus of Lyon

The attributed author of Liber adversus Joannem Scotum is Florus of Lyon (Florus Lugdunensis), a deacon of the Church of Lyon and one of the leading Carolingian scholars. Florus was a disciple of the Lyon school under Archbishop Agobard and his successor Amolo, and was renowned for his erudition in Scripture and the Church Fathers. Contemporary testimony refers to Florus as “the most widely read of Carolingian theologians… an expert in law and liturgy.”

Florus had produced important scholarly works, including compilations of patristic commentary (especially Augustinian theology) on the Pauline Epistles. He had earlier defended aspects of Gottschalk’s view of predestination in a separate Sermo de praedestinatione after the Synod of Quierzy in 849. When Eriugena’s treatise appeared, Florus—likely with the approval of Archbishop Remigius of Lyon—wrote this rebuttal in Lyon’s name.

It is generally accepted by modern scholars that Florus is the author of Liber adversus Joannem Scotum. The incipit of the text itself names “libellus Flori” (the little book of Florus) against John. However, there was some earlier uncertainty in attribution. In certain medieval manuscripts or catalogs, works on predestination were ascribed to Remigius, Archbishop of Lyon, possibly because Remigius was Florus’s ecclesiastical superior. Recent scholarship has clarified these attributions: the Liber adversus Joannem Scotum and related texts are now confidently credited to Florus rather than Remigius.

Florus is often referred to as “Florus Magister” in modern literature, denoting his role as a master scholar in Lyon. He brought to this work not only his theological acumen but also his extensive knowledge of St. Augustine and other Fathers—knowledge he would deploy to counter Eriugena’s arguments.

Overview and Structure of the Work

The Liber adversus Joannem Scotum is a systematic, point-by-point refutation of John Scotus Eriugena’s treatise on predestination. It opens with a fiery preface (praefatio) in which Florus sets the tone by denouncing Eriugena in uncompromising terms. He describes Eriugena as “a certain most vain talker (vaniloquus) and babbler” whose writings on divine predestination and prescience and on human free will are “full of lies and errors, against the faith and truth of God.”

Florus laments that although learned readers easily reject John’s arguments as nonsense, many others have been impressed by John Scotus’s reputation as a scholar. Thus, Florus says, they are “led astray by his empty verbosity”, admiring him as if he taught something profound, when in fact he subverts his listeners’ respect for Scripture and the Fathers. This preface clearly states Florus’s intention: to expose Eriugena’s errors and protect the faithful from his influence.

Following the preface, the work is divided into at least 14 chapters (capitula), each of which targets specific propositions or definitions put forward by Eriugena. Florus closely follows the structure of Eriugena’s own treatise, quoting or paraphrasing John’s arguments and then rebutting them in turn. For example, Chapter I begins by reciting Eriugena’s opening “definitions” on the topic, which Florus then proceeds to criticize. Each subsequent chapter is introduced by a similar formula (e.g. “Secundo capite octo nobis praedefinitiones proponit…” – “In the second chapter he proposes eight definitions to us…”) and then Florus’s response.

Throughout these chapters, Florus addresses Eriugena’s key claims about God’s foreknowledge (praescientia), predestination (praedestinatio), grace, and free will. In the course of the work, Florus tackles a series of theological propositions that Eriugena had advanced: for instance, Eriugena’s claim that “all God’s foreknowledge is predestination, and likewise all predestination is foreknowledge”. Florus labels this claim false as it confuses categories that must be distinguished.

He also engages with Eriugena’s idea that “all predestination is wholly a preparation of grace”, implying that God predestines only the elect to grace and does not predestine anyone to punishment. In each case, Florus first quotes or summarizes Eriugena’s words (often calling them “inept definitions”) and then provides a rebuttal drawing on Scriptural evidence and patristic authorities.

The work is richly stocked with biblical citations – Florus marshals St. Paul, the Gospels, and prophetic texts – as well as references to St. Augustine and other Fathers, to counter Eriugena’s purely rational arguments. By the end of the treatise (around Chapter XIV), Florus has dissected Eriugena’s treatise in full, having demonstrated (in his view) that each of John’s propositions must be rejected.

It is worth noting that Florus writes with a clear didactic structure: he often restates Eriugena’s point succinctly, then refutes it. This made his work something of a commentary on Eriugena, doubling as a convenient summary of John’s book and a critique. The chapters build cumulatively toward defending a coherent alternative doctrine – essentially, Florus defends the Augustinian view that while God’s foreknowledge extends to all events (even sins), predestination properly applies to good (the elect and their rewards) and not to evil deeds.

Major Theological Arguments and Florus’s Refutation of Eriugena

At the heart of Liber adversus Joannem Scotum are profound theological and philosophical arguments about divine omniscience, grace, free will, and the nature of predestination. Florus’s polemic targets Eriugena’s positions on each of these points:

Predestination vs. Foreknowledge

Eriugena had essentially equated God’s predestination with His foreknowledge, presumably to avoid saying God actively predestines anyone to evil. Florus fiercely rejects this equation of praedestinatio with praescientia. He argues that while God in His omniscience eternally foreknows all future events (good and evil alike), this does not mean He has predestined all those events.

Florus draws a sharp distinction: “God has eternally foreseen (praescierit) all things that were to be – both good and evil – but He has eternally predestined only the good things which He Himself would do, whether by His grace or by His just judgment”. In other words, predestination, properly speaking, applies to God’s positive decree of benefits (and just punishments) for His creatures, not to the mere foresight of human acts.

By making this distinction, Florus preserves God’s holiness: God can “foreknow” evil without Himself causing or predestining evil. Florus points out that Eriugena’s failure to maintain this distinction leads him into error – if one said God’s predestination covers evil acts in the same way as good, it would either implicate God in the authorship of sin or force one (like Eriugena) to deny predestination of evil entirely.

Florus’s nuanced stance is that God “could foreknow evils, but could not predestine them”. Thus, he upholds that predestination is a subset of God’s foreknowledge – specifically, the part of God’s foreknowledge that involves His positive plan to bring about good (including the good of justly punishing sin).

Predestination of the Elect and Reprobate

A related point is whether there is predestination to damnation. Eriugena emphatically said no, there is only predestination to life. Florus responds by carefully affirming a form of twofold predestination (to bliss for the good and to punishment for the wicked), but he does so in a way that avoids making God the author of sin.

He cites extensively from Scripture to show that God’s ordination of punishment for the wicked is indeed part of His plan. For example, Florus invokes biblical passages about the fate of Judas, the Antichrist, and the ungodly: “If Antichrist and his followers are not predestined to judgment, how do the Scriptures say, ‘the beast goes into perdition…these words are trustworthy and true’?”

He cites St. Paul and other authorities to demonstrate that God’s justice has prepared punishment for sinners, which, in Florus’s view, falls under predestination (in the sense that God predetermines to requite evil with just punishment). However, Florus carefully maintains that while God predetermines the penalty for sin, He does not cause the sin itself – the sinners fall by their own free will and merit punishment which God, as a just judge, has foreordained to impose.

This fine distinction allows Florus to concur with Gottschalk’s camp that there is a predestination of the wicked (to just punishment) without implying God’s complicity in moral evil. Florus backs this up by citing Saint Augustine and other Fathers who taught that while no one is saved except through predestined grace, the damned are such by their own fault even though their punishment is in accordance with God’s eternal decision.

Human Free Will and Grace

Though Florus spends less time explicitly discussing “liberum arbitrium” in abstract, the issue of free will underlies much of the argument. Eriugena had framed his denial of double predestination partly in defense of free will – implying that if God predestines some to sin or damnation, human freedom and responsibility would be nullified.

Florus counters by asserting that proper doctrine upholds both predestination and free will in their due order. He maintains that predestination (rightly understood) does not compel anyone to sin; instead, it is God’s effective plan for salvation of the good and just retribution for the wicked, in harmony with each person’s free choices.

In the preface, Florus accuses Eriugena of distorting “the true freedom of the human will” (vera humani arbitrii libertate) by his novel teachings. This suggests Florus believed Eriugena, by denying any role of God’s predestining will in human salvation, veered toward Pelagianism – over-exalting free will to the detriment of grace.

Indeed, Florus frequently quotes Augustine to reassert that any human goodness is a result of God’s grace foreordained before the ages, not of human effort alone. At the same time, Florus upholds that humans are responsible for their sins and that God’s foreknowledge/predestination in no way necessitates those sins.

Thus, in Florus’s theology, grace and free will are not opposed: God’s predestined grace enables the elect to do good, and those who do evil do so freely and are justly (predestinately) punished. Florus’s position is essentially Augustinian, and he explicitly aligns with what he calls the “orthodox” understanding of Augustine.

Notably, Florus and his allies even exposed that some quotations Eriugena used as “Augustine” were spurious; Florus prided himself on identifying Pseudo-Augustinian forgeries that John had unwittingly cited. By purging false authorities and reinstating authentic Augustine, Florus reinforced the patristic foundation for the correct view of free will and grace.

Use of Reason vs. Authority

A significant philosophical aspect of the debate is Eriugena’s reliance on dialectics and rational argument. Eriugena was a neo-Platonic thinker who believed reason could penetrate theological questions, and in De Praedestinatione he often employed logical paradoxes and definitions.

Florus seizes on this as a flaw: in the very first lines, he complains that John argued “with human and philosophical arguments, without any authoritative proof from Scripture or Fathers” and presumed to define doctrine by “his own presumption alone”. Florus’s counter-method is deliberately opposite: he saturates his rebuttal with biblical citations and patristic quotations, thereby grounding each refutation on auctoritas.

This reflects a core clash of methodology – rationalism vs. tradition. Florus accuses John of “trusting his own reason” over revelation, and even of sophistry. In one colorful remark preserved by a later writer, Florus and Prudentius likened John’s work to “Irish porridge” (pultes scottorum), implying it was a muddled concoction of arguments with little solid nourishment of truth.

Florus systematically highlights internal contradictions in Eriugena’s treatise and faults his heavy use of Greek philosophical concepts. In doing so, Florus aims to show that right theology must be founded on Scripture and the consensus of the Fathers, not on novel logical speculation.

Ironically, Florus himself was capable of rigorous logical analysis – as modern scholars note, Florus and his colleague Prudentius were quite adept with Aristotelian categories and even used logical techniques to dismantle Eriugena’s positions. But crucially, they did so in defense of traditional authority.

This tension – how far to employ dialectic in theology – is a philosophical undercurrent of the work. Florus’s stance is clear: whenever human reason seems to conflict with the received faith (as taught by Scripture/Augustine), reason must yield. In Florus’s view, John Scotus failed to observe this limit, thereby falling into error.

Polemical Style and Strategies

While Liber adversus Joannem Scotum contains substantive theology, it is also a polemical work with a sharp rhetorical edge. Florus does not shy away from ad hominem language and biting criticism when addressing John Scotus Eriugena and his ideas. Several polemical strategies stand out:

Personal Attacks and Epithets

Florus’s language about Eriugena is often scathing. In the preface he brands Eriugena a “vain” and “garrulous” man full of “empty loquacity”, accusing him of intellectual pride. Such barbed epithets continue throughout the text; Florus frequently refers to John’s arguments as “folly,” “nonsense,” or “blasphemy,” setting an aggressively dismissive tone.

The Catholic Encyclopedia notes that Florus’s and Prudentius’s responses to Eriugena were “full of bitter personal attacks on Eriugena”. This was a deliberate tactic to undermine John’s credibility. By attacking the man (as presumptuous and unfaithful), Florus bolsters his case that no one should take Eriugena’s teachings seriously despite his scholarly reputation.

The “Irish porridge” jibe mentioned above was a memorable example of this personal ridicule, likening Eriugena’s work to a bowl of mixed mush. Florus clearly wanted to ensure Eriugena’s ideas would not just be refuted, but held in contempt by orthodox readers.

Appeal to Authority

Alongside personal jabs, Florus uses the argument from authority as a polemical weapon. He continually contrasts Eriugena’s lack of authoritative support with the weight of Scripture and Church Fathers on the orthodox side. In the preface, he remarks that John made bold claims “with no Scriptural or patristic proof offered”.

Florus then floods his rebuttal with quotations from the Bible (Paul, the Gospels, prophets) and especially from St. Augustine, thus implicitly chastising Eriugena for ignoring these sources. This strategy not only reinforces Florus’s theological points but also serves to isolate Eriugena as an outlier, implying that all the authoritative voices of Christian tradition stand against him.

In Florus’s presentation, John Scotus is one man against the Fathers – a damning position in an age when fidelity to tradition was paramount. By invoking councils, canon law, and revered doctors of the Church at every turn, Florus gives his polemic an air of overwhelming authoritative consensus.

He even corrects John’s use of authorities: for example, Florus identified that some supposed Augustine passages John cited were forgeries, thereby undercutting John’s appeal to Augustine. In sum, Florus’s authoritative barrage not only bolsters his argument but also portrays Eriugena as arrogant for relying on “human philosophy” over established authority.

Highlighting Contradictions and Absurdities

Florus adopts a pedagogical, prosecutorial tone, dissecting John’s text to expose internal contradictions and what he sees as absurd conclusions. He will often restate John’s position in a reductio ad absurdum style before refuting it.

For instance, Florus points out that if one followed Eriugena’s logic that God predestines nothing evil, one would have to deny that God has eternally prepared judgment for the wicked – which contradicts explicit scriptural testimony. By driving Eriugena’s propositions to uncomfortable implications (such as the denial of God’s omnipotence or justice), Florus makes John’s teachings look not only unorthodox but incoherent or impious.

He repeatedly uses phrases like “nonsense” or “this begins in falsehood and ends in falsehood” when summarizing John’s chapters. This methodical takedown is a polemical strategy to ensure that even if a reader lacks theological expertise, they come away convinced that Eriugena’s ideas don’t add up and should be rejected.

Overall, Florus’s style in Liber adversus Joannem Scotum is impassioned and uncompromising. He combines scholarly argument with polemical fire, a dual approach that castigates Eriugena personally while also demolishing his positions intellectually. This blend of erudition and invective was a hallmark of Carolingian polemics.

Reception and Influence in Medieval Thought

The immediate reception of Liber adversus Joannem Scotum was closely tied to the official Church response to the predestination controversy. In the years following its composition, Florus’s arguments (along with those of Prudentius of Troyes) prevailed in ecclesiastical councils.

At the Council of Valence (855) and the Council of Langres/Savonnières (859), the Frankish bishops formally condemned Eriugena’s teachings on predestination. The Council of Valence – attended by Florus’s patron Remigius of Lyon, among others – echoed Florus’s positions almost point for point.

The council’s canons affirmed that while God’s grace predestines the elect to salvation, those who are lost are foreknown by God and justly damned for their wickedness (not predestined to sin by God, but predestined in view of their sin to punishment). In condemning Eriugena, the council fathers even employed colorful language reminiscent of Florus’s polemic: they derided John’s treatise as “pultes Scotorum” or “Irish porridge,” implying it was a confused mess of argument.

Thus, in the eyes of contemporaries, Florus’s rebuttal had done its work – John Scotus Eriugena’s doctrine was officially censured as erroneous, and Florus’s more traditional doctrine was endorsed.

After 859, the predestination controversy subsided. Gottschalk remained imprisoned, and the Church largely steered a middle course that rejected both extreme double predestination and Eriugena’s denial of any predestination to punishment. Florus’s influence can be seen in this balanced position: the councils upheld that there is “twofold predestination” only in the sense of God’s grace and God’s retributive justice (not a predestination that causes sin).

Beyond the 9th century, Liber adversus Joannem Scotum itself did not circulate widely as a distinct work. The immediate controversy resolved, Florus’s text likely remained in the archives of Lyon and perhaps in a few theological collections. In the High Middle Ages, interest in John Scotus Eriugena revived but focused on his great philosophical work Periphyseon (On the Division of Nature) rather than his ill-fated predestination tract.

Interestingly, Liber adversus Joannem Scotum experienced a sort of resurrection in the 17th century. During the post-Reformation and Jansenist controversies (which revisited Augustine’s doctrines of grace and predestination), scholars turned back to the Carolingian predestination dispute for precedents.

In 1650, a Parisian publisher (Jean Billaine) issued Vindiciae Praedestinationis et Gratiae (“Vindication of Predestination and Grace”), which collected writings of Augustine and his early medieval defenders. This publication’s elaborate frontispiece engraving depicts key figures of the 9th-century debate – notably St. Augustine at top, and at the bottom a gathering of Carolingian theologians and bishops including “Florus Magister Lyugdunensis” (Florus of Lyon) and others, shown supporting a banner of “Praedestination and Grace”.

Frontispiece of a 1650 Paris edition showing Florus of Lyon honored alongside other Carolingian theologians for refuting the errors of John Scotus.

Florus is literally enshrined there as a champion of orthodoxy, alongside the Council of Valence and the Church of Lyon. This indicates that by the 17th century, Florus’s work against John Scotus was not forgotten by scholars – on the contrary, it was valorized as a classic defense of Augustinian doctrine during a time when the Catholic Church was debating grace and free will anew.

In modern times, the work’s influence is primarily as a subject of scholarly interest in Carolingian theology. Twentieth-century researchers rediscovered Florus’s contributions; for example, Florus’s critical method in exposing Pseudo-Augustinian texts has been acknowledged as an early example of patristic scholarship.

Manuscripts, Editions, and Translations

For many centuries, Liber adversus Joannem Scotum survived in relative obscurity, mainly in the manuscript traditions of Lyon and possibly in compendia related to the predestination controversy. The text was first brought to wider modern attention in the 17th and 19th centuries.

The first full printed edition appeared in the 19th century in J.-P. Migne’s Patrologia Latina, vol. 119. Migne printed Liber adversus Joannem Scotum from the available manuscripts, under Florus’s name, spanning columns 101–250 of volume 119. This 19th-century edition, though not critical by modern standards, made the text accessible to scholars and firmly established the attribution to Florus.

In recent years, there has been progress toward a true critical edition. Scholars began re-examining Florus’s entire oeuvre in the mid-20th century (notably Célestin Charlier and others), and as of the early 21st century, Florus’s works are being published in the Corpus Christianorum, Continuatio Mediaeualis series.

The Corpus Christianorum project “Flori Lugdunensis Opera Omnia” (complete works of Florus) has been underway since 2002. This will include a freshly edited Latin text of Liber adversus Joannem Scotum based on all known manuscripts, with proper critical apparatus – an important upgrade from Migne’s text.

Regarding translations, portions of Florus’s tract have been translated in academic publications. Notably, the 2010 volume Gottschalk & the Medieval Predestination Controversy: Texts Translated (edited by Victor Genke and Francis X. Gumerlock) includes English translations of many relevant documents.

A complete English translation of Liber adversus Joannem Scotum is still a desideratum, though the Latin is readable with a good background in theological Latin. Other modern languages: there have been scholarly studies in French and German that paraphrase or translate key passages, for example, studies by Claude Marie Doutreloux or Klaus Zechiel-Eckes on Florus.

Conclusion

Liber adversus Joannem Scotum stands as a testament to the Carolingian renaissance’s blend of learning and faith: it is simultaneously a product of Carolingian scholarly culture and a passionate defense of what that culture deemed the true Christian doctrine of predestination.

Florus’s work provides valuable insight into 9th-century theological debates and demonstrates the complex interplay between reason and authority in early medieval thought. His careful distinctions between predestination and foreknowledge, and his defense of a nuanced view of free will and grace, show the sophistication of Carolingian theology.

The legacy of this text reminds us that theological controversies often reach their resolution not merely through philosophical arguments but through the establishment of institutional consensus—in this case, through councils and authoritative refutations. Florus’s victory over Eriugena in the predestination controversy shaped subsequent medieval understanding of Augustine and established boundaries for acceptable theological discourse on divine sovereignty and human freedom.

---

Sources:

• Florus of Lyon, Liber adversus Joannem Scotum, in Migne PL 119, cols. 101–250
• J.P. Kirsch, Catholic Encyclopedia (1909) on Florus and John Scotus
• Valence III (855) conciliar canons
• Stanford Encyclopedia of Philosophy (2020) on John Scotus Eriugena
• V. Genke & F. Gumerlock (eds.), Gottschalk & Medieval Predestination Controversy (2010)
• C. Charlier, Études Érigéniennes (1945)
• K. Zechiel-Eckes (1999) on Florus