A 12th-century ethical treatise that revolutionized medieval moral philosophy by locating sin in intention rather than action, arguing that moral culpability depends entirely on the agent's will and knowledge of divine commands rather than external deeds or their consequences.

Historical Context

Authorship: The treatise Ethica (often called Scito te ipsum, “Know Yourself”) is firmly attributed to Peter Abelard (Petrus Abaelardus). Contemporary evidence confirms Abelard as the author – for instance, he himself refers to writing an “Ethics” in his commentary on Romans (www.bibliographia.co). Medieval readers like William of St-Thierry and Bernard of Clairvaux knew of Abelard’s Scito te ipsum by that title (books.openedition.org). Modern scholars are in consensus that this work is genuinely Abelard’s; there is no serious dispute about its authorship (www.bibliographia.co). Its incomplete state (the text breaks off early in Book II) is likely because Abelard never finished it, rather than later tampering (plato.stanford.edu). Indeed, Abelard’s adversities (including a condemnation in 1140) may have halted its completion.

Date of Composition: Ethica was composed in the late 1130s (www.bibliographia.co), during the final period of Abelard’s scholarly activity. This dating rests on internal evidence: in his Expositio on St. Paul’s Epistle to the Romans (written mid-1130s), Abelard postpones certain ethical questions “for fuller treatment in the Ethics” (www.bibliographia.co). The Ethica likely took shape after Abelard’s return to teaching in Paris (c.1136) and before his condemnation at the Council of Sens in 1140. It represents the “mature thought of a man who had experienced much in life” (iep.utm.edu), suggesting it was one of his later works. The second book is fragmentary – Abelard abandons it after only a page (www.cambridge.org) – perhaps due to the turmoil of 1139–1140 when he faced renewed accusations of heresy.

Provenance: Abelard probably began Ethica while teaching on the Mont Ste-Geneviève in Paris (plato.stanford.edu) (plato.stanford.edu), or possibly at the Paraclete, the monastic community he founded and entrusted to Heloise. By the late 1130s he had withdrawn from his earlier monastic post in Brittany and was again active around Paris (plato.stanford.edu). The work’s content – a systematic ethical treatise rather than a monastic exhortation – suggests a scholarly, clerical milieu. It was likely written as lecture material or a treatise for students of theology and philosophy. Abelard wrote amid the emerging Parisian schools that valued dialectical reasoning, which shaped the form of this ethical discourse (vdoc.pub).

Historical Setting: The Ethica was composed in a 12th-century context of intellectual ferment and ecclesiastical reform. Abelard’s career unfolded during the growth of the scholastic method in theology and the early days of the University of Paris. He was a pioneering logician who applied reason to theology – a stance that brought him into conflict with more traditional authorities like St. Bernard of Clairvaux (iep.utm.edu) (iep.utm.edu). Politically and culturally, the late 1130s were marked by church councils cracking down on heterodoxy. In 1139 Pope Innocent II convened the Second Lateran Council (which condemned various heresies), and Bernard was mobilizing against Abelard’s teachings. Abelard wrote Ethica just before the 1140 Council of Sens, at which Bernard led the charge to condemn Abelard (plato.stanford.edu). Thus, Ethica emerged during Abelard’s final struggle for intellectual freedom. It also comes after Abelard’s famous love affair with Heloise (now abbess of the Paraclete) – their personal story was well known, and Abelard’s insight into sin, intention, and conscience was surely informed by his life experience (iep.utm.edu) (iep.utm.edu).

Intended Audience: Abelard’s Ethica was aimed at educated clerics and students of theology. Unlike monastic moral treatises, it is written in the mode of a scholastic disputation, drawing on Scripture and Church Fathers rather than on secular authorities (www.bibliographia.co). Abelard likely intended it for the schools – to clarify the nature of sin and virtue for fellow scholars and advanced students. He opens with the words Mores dicimus (“We are speaking of morals”), signaling a formal inquiry (books.openedition.org). The original audience would have included his circle of pupils and correspondents (Heloise herself had posed moral questions to him (www.bibliographia.co)). Abelard wrote it to articulate a distinctly Christian ethics grounded in reason and faith, perhaps to counter misinterpretations of sin in his time. In sum, Ethica was written pro bono ecclesiae, for the benefit of the Church’s thinkers, offering a reasoned account of morality that Abelard felt was urgently needed in his era (vdoc.pub).

Theological Significance

Core Themes: Abelard’s Ethica is most famous for its intentionalist ethics – the doctrine that moral guilt or merit lies in the agent’s intention (intentio) rather than in the external act (iep.utm.edu) (www.bibliographia.co). Abelard argues that “God considers not what is done, but in what spirit it is done” (www.bibliographia.co). Thus, an action in itself is not sinful or virtuous; only the consent of the will to what one believes is wrong constitutes sin. He carefully defines concepts like vice, desire, consent, action, and distinguishes “sin in act” vs “sin in intention.” For example, Abelard infamously states that someone who unwittingly commits a wrong act (believing it right) incurs no sin – whereas someone who intends evil, even if no evil act occurs, is guilty (iep.utm.edu) (iep.utm.edu). He illustrates this with biblical and hypothetical cases: the Crucifixion involved many agents – Christ, Judas, the Jewish leaders – whose moral culpability differed based on intent (iep.utm.edu) (iep.utm.edu). The Jews who executed Jesus “were acting in accordance with what they believed to be God’s will” and so “sinned in act but not in fault,” whereas Judas, who intended betrayal, was truly guilty (iep.utm.edu) (iep.utm.edu). Abelard’s ethical system is a precedent for examining subjective conscience in moral theology.

Relation to Patristic Thought: Abelard frames his arguments with Scripture and the Church Fathers (www.bibliographia.co). He stands in continuity with St. Augustine in emphasizing the inner will: Augustine had said that all sin is in the consent of the will (and that “God weighs the heart”). Abelard explicitly cites Augustine and Jerome and situates his teachings within orthodox doctrine (www.bibliographia.co). Yet he goes beyond the Fathers in systematic detail. For instance, Abelard echoes St. Paul’s idea that “whatever is not of faith is sin” (Rom 14:23), building on it to argue that acting against one’s conscience is always sinful (iep.utm.edu) (iep.utm.edu). He also invokes the principle of “love of God and neighbor” from the Gospels: loving intention is the root of virtue, contemptuous intention the root of sin (iep.utm.edu). In method, Abelard’s rational analysis of concepts like vice and will was novel – but not heretical. He drew on patristic definitions (e.g. Isidore’s distinctions of virtues (www.bibliographia.co)) to ensure his ethics aligned with Christian tradition. In many ways, Ethica complements Abelard’s own theology of atonement in his Commentary on Romans, where he held that true Christian virtue flows from the love inspired by Christ (iep.utm.edu) (iep.utm.edu).

Biblical Foundation: The treatise is grounded in Scripture. Abelard frequently references the Ten Commandments, Jesus’s teachings, and apostolic writings to define sin and virtue. A key biblical cornerstone is Jesus’s teaching that the great commandment is love – Abelard says moral goodness is “intending to show love of God and neighbor” (iep.utm.edu). He also leans on St. Paul: for example, Abelard cites Paul’s discussion of food sacrificed to idols and conscience (Rom 14 and 1 Cor 8) to argue that violating one’s conscience is sinful even if the act is indifferent (iep.utm.edu) (iep.utm.edu). The story of Peter’s denial might be discussed – sinning under fear could be seen as partial consent. Abelard also alludes to the Fall of Adam and human inclination: he notes that concupiscence (disordered desire) itself is not a sin unless we consent to it (iep.utm.edu) (iep.utm.edu). Throughout, Ethica interprets biblical teachings on sin (e.g. “If you lust in your heart, you have committed adultery”) as emphasizing consent of heart over the external deed.

Controversies and Heterodoxy: In Abelard’s lifetime, his ethical views stirred concern. Critics feared that his strict focus on intention downplayed the objective evil of certain acts. For example, Abelard’s claim that a man who sleeps with a woman believing her to be his wife commits no sin (since there’s no intent to commit adultery) (iep.utm.edu) sounded shocking to some. William of St-Thierry, in 1140, denounced Scito te ipsum (along with Abelard’s Sic et Non) as “monstrous in name and doctrine” (books.openedition.org) – effectively accusing Abelard of moral relativism. Bernard of Clairvaux likewise complained that Abelard “disputed many points of morals against the custom of the Church” (books.openedition.org) (books.openedition.org). These critics likely misunderstood Abelard as saying external actions don’t matter at all. In truth, Abelard maintained that wrong acts are objectively disordered, but without guilty intent they are “sin in act, not in soul” (iep.utm.edu). He did not advocate laxity – he famously held that an immoral intention is damning even if no act occurs (iep.utm.edu) (iep.utm.edu). Later scholastics would critique Abelard for ignoring the role of the act itself in moral evaluation. Thomas Aquinas, for example, argued that both the object and intention must be good for an act to be virtuous, implicitly responding to Abelard’s one-sided focus on intent. Despite controversies, Abelard’s central insight – the importance of subjective culpability – was eventually absorbed into Church teaching (e.g. the notion that mortal sin requires full knowledge and consent mirrors Abelard’s stance (iep.utm.edu) (iep.utm.edu)).

Influence on Later Thought: Abelard’s Ethica had a profound if indirect influence on the development of moral theology. In the short term, its circulation was limited (surviving in only a handful of manuscripts) and its intentionalism was too radical for many 12th-century contemporaries. Yet by framing ethics as a rational, dialectical analysis, Abelard helped lay the groundwork for moral theology as a distinct discipline (vdoc.pub) (vdoc.pub). Scholars have noted that Abelard “paved the way for the development of moral theology to an independent discipline” by taking moral questions out of scriptural commentary and treating them in a systematic treatise (vdoc.pub) (vdoc.pub). In the 13th century, Albert the Great and Thomas Aquinas would build more elaborate moral theories that still echoed Abelard’s questions: e.g. Thomas agrees that “actus exterior sequitur intentionem” to a degree, and the primacy of conscience in moral acts. Abelard’s student Alan of Lille explicitly refers to a “theologia moralis” (moral theology), a concept arguably modeled on Abelard’s approach (vdoc.pub). Modern scholars see Abelard as a forerunner of the emphasis on individual conscience and intention that would flourish in later scholastic and even Reformation thought (plato.stanford.edu) (iep.utm.edu). In philosophy, Abelard’s idea that ethics is about subjective intention resonates with certain strands of modern ethics (e.g. Kant’s focus on the good will). Thus, while Ethica was not widely read in the medieval period, its ideas filtered through in the questions it posed and the method it exemplified.

Manuscript Tradition and Editions

Manuscripts: Abelard’s Ethica survives in only a small number of medieval manuscripts, reflecting its limited circulation. Scholars identify five known manuscript witnesses (books.openedition.org). Four of these bear the title Scito te ipsum, while one fragmentary copy did not include the title or the end of Book I (books.openedition.org). Notable manuscripts include a 14th-century copy in Oxford (Balliol College MS 296), which contains Ethica along with other Abelard works (www.scribd.com) (www.scribd.com). This Balliol manuscript is important because it preserves the complete text of Book I (Migne’s edition had missing lines that the Oxford copy supplies) (www.scribd.com) (www.scribd.com). Another witness is a 15th-century manuscript in the Stadtbibliothek, Mainz (MS lat. 76), which interestingly attributes the treatise to Abelard in a marginal note and continues, after Ethica, with unrelated texts (www.scribd.com) (www.scribd.com). A further copy was once at the Abbey of Tegernsee – it was seen in the 18th century by the editor Bernard Pez (www.scribd.com) – and likely now in the Bayerische Staatsbibliothek, Munich (Clm 18597) (www.scribd.com). The manuscript tradition is complex: some copies were incomplete or conflated with other works, showing the treatise wasn’t widely copied. By the 17th and 18th centuries, antiquarians made transcripts of Abelard’s Ethica (e.g. extracts in Bodleian Library MS Wood Donat. 2) to circulate its content (www.scribd.com) (www.scribd.com). All known manuscripts derive from the later Middle Ages, meaning the text may have lain “dormant” for years and was “rediscovered” by scholars in Early Modern times (www.brepolsonline.net).

Critical Editions: The Ethica was first printed in the 1720s by Bernard Pez, based on a manuscript from Tegernsee (www.gutenberg.org). Pez’s edition (reproduced in Migne’s Patrologia Latina vol.178) became the standard for centuries, but it has deficiencies – it omits the end of Book I and contains transcription errors (www.scribd.com) (www.scribd.com). A major modern edition was prepared by David E. Luscombe: Peter Abelard’s Ethics (Oxford: Clarendon Press, 1971) provides a Latin text with an introduction, English translation, and notes (www.bibliographia.co) (www.bibliographia.co). Luscombe’s work corrected many of Pez’s mistakes using the Balliol and other manuscripts. The most authoritative edition today is by Rainer M. Ilgner, published as Petri Abaelardi Ethica in Corpus Christianorum Continuatio Mediaeualis vol. 190 (Brepols, 2001) (plato.stanford.edu) (plato.stanford.edu). Ilgner’s edition, with a German introduction, collates all known manuscripts and is now the reference text (plato.stanford.edu) (www.bibliographia.co). (Ilgner also prepared a bilingual Latin-German edition for the Fontes Christiani series in 2011.) As of 2025, a new English translation by Ilgner is available in the Brepols Library of Christian Sources, presenting Abelard’s Latin alongside a fresh translation (www.brepolsonline.net).

Translations: Abelard’s Ethica has been translated into modern languages. An early English translation appeared in 1935: Abelard’s Ethics translated by J. Ramsay McCallum (Oxford: Blackwell, 1935). Luscombe’s 1971 edition includes an English translation facing the Latin. Another widely used English version is in Peter Abelard: Ethical Writings (Hackett, 1995), translated by Paul Vincent Spade (plato.stanford.edu). Spade’s translation is accessible and appears alongside Abelard’s Dialogue of a Philosopher with a Jew and a Christian. In French, there is a translation by Marcela Aron (1933) and discussion in recent scholarship, though no full modern French edition exists in print. A complete German translation accompanies Ilgner’s Fontes Christiani edition (2011). These translations make Ethica available to a wider readership interested in medieval philosophy.

Textual Issues: The main textual issue is the incomplete second book – all manuscripts break off shortly after the start of Book II, mid-sentence. There is no evidence Abelard wrote more; scholars assume the work is unfinished (www.cambridge.org). Editors sometimes speculate on what topics Book II would have covered (Abelard’s other writings suggest it would discuss how to “do good” following the analysis of sin in Book I (www.cambridge.org)). Variants between manuscripts are relatively minor, typically differences in chapter headings or wording (www.scribd.com). One manuscript (Mainz MS) shows extra chapter divisions and even tacks on unrelated material after Abelard’s text (www.scribd.com), but the core content of Ethica is consistent across copies. The Migne/Pez text lacked some lines that were later recovered: for example, a portion of the conclusion of Book I was missing in PL but found in the Balliol MS (www.scribd.com) (www.scribd.com). Modern editions have restored these, so that we now have the full text as Abelard wrote it (to the point he stopped). Overall, the textual tradition, though sparse, has been sufficiently clarified by critical scholarship that we can read Ethica with confidence in its fidelity to Abelard’s original words.

Author Biography

Life: Peter Abelard (Pierre Abélard) was born in 1079 in Le Pallet, Brittany (plato.stanford.edu), the eldest son of minor nobility. Renouncing his inheritance for scholarship, he became a wandering intellectual, studying under masters like Roscelin of Compiègne and William of Champeaux in Paris (iep.utm.edu) (iep.utm.edu). By his early twenties Abelard was famed for his prowess in logic, engaging in celebrated debates on universals (he earned the title “the keenest thinker and boldest theologian of the age” in the eyes of contemporaries). Around 1115, while master at Notre-Dame, Abelard entered a fateful romance with his brilliant pupil Héloïse d’Argenteuil (iep.utm.edu). Their passionate affair led to a secret marriage and a son, but when Héloïse’s guardian, Canon Fulbert, discovered it, he had Abelard violently castrated in 1117 (iep.utm.edu) (iep.utm.edu). Humiliated, Abelard became a monk at the Abbey of St. Denis, and Héloïse took vows as a nun. Abelard recounted these events and his inner turmoil in his autobiographical letter Historia Calamitatum (“History of My Misfortunes”) (plato.stanford.edu).

Career: Abelard’s career had soaring highs and crushing lows. As a philosopher, he founded the dialectical school of nominalism and wrote influential works on logic (Logica Ingredientibus and Dialectica). After the tragedy with Héloïse, Abelard shifted focus to theology. In the 1120s he wrote Theologia “Summi Boni” (Theology of the Highest Good), which provoked his first condemnation for heresy at the Council of Soissons in 1121 – churchmen objected to his rational analysis of the Trinity (iep.utm.edu). Forced to burn his own book (iep.utm.edu), Abelard retreated to a hermitage and later became Abbot of a turbulent monastery in Brittany (St. Gildas-de-Rhuys), though with little success in monastic governance (plato.stanford.edu) (iep.utm.edu). By 1133 he returned to the Paris area, teaching on Mount Ste-Geneviève to throngs of students (plato.stanford.edu). During this period he composed major works: Sic et Non (a collection of conflicting authorities), biblical commentaries, the Dialogue of a Philosopher with a Jew and a Christian, and the Ethica. His innovative teaching and writings attracted both admiration and alarm. The great Cistercian abbot Bernard of Clairvaux saw Abelard’s rationalism as a threat to faith. Tensions climaxed in 1140 when Bernard denounced Abelard’s doctrines and persuaded the Council of Sens to condemn 19 propositions from Abelard’s works (plato.stanford.edu) (plato.stanford.edu). Abelard, not even allowed to properly defend himself, was silenced by ecclesiastical authority and headed to Rome to appeal, but never arrived (plato.stanford.edu). Instead, he found refuge under the protection of Peter the Venerable at the Abbey of Cluny (plato.stanford.edu). There, Abelard spent his final months in relative peace, even reconciling formally with Bernard.

Ruins of Cluny Abbey, where Abelard found sanctuary under Abbot Peter the Venerable after his condemnation in 1140, spending his final years in peace before his death in 1142
License: CC BY-SA 2.0. (Wikimedia Commons)

Historical Context: Abelard lived in a 12th century renaissance of learning – the era of early universities and scholastic summae. Contemporary figures included Hugh of St. Victor in theology, William of Conches in philosophy, and Bernard of Clairvaux in spirituality. Politically, the Church was asserting authority via reform councils, and the first Crusades had recently occurred (Abelard and Héloïse’s drama unfolded not long after the First Crusade). Abelard’s Paris was a center of intellectual ferment, where classical logic was being rediscovered and applied to Christian doctrine. His bold use of reason in theology (applying Aristotle’s logic to mysteries of faith) was ground-breaking – he even coined the term “theologia” in its modern sense of a rational study of God (plato.stanford.edu). But this put him at odds with conservative factions; Abelard’s conflict with Bernard epitomizes the clash between dialectica and traditional monastic theology. Abelard was also a gifted poet and is credited with secular love songs (now lost) that he wrote for Héloïse, reflecting the courtly culture of the time (plato.stanford.edu). After their separation, Abelard continued to correspond with Héloïse, advising her and the nuns of the Paraclete on matters of doctrine and practice (these letters, and Héloïse’s responses, are literary masterpieces of the period). In short, Abelard’s life mirrors the vibrant but tumultuous intellectual life of 12th-century France.

Legacy: Abelard is remembered as one of the great minds of the Middle Ages – sometimes called “the first modern theologian” for his insistence on critical inquiry. In philosophy, he pioneered solutions to the problem of universals and contributed to the foundation of conceptualism. In theology, despite being twice condemned, his methods (particularly the Sic et Non approach of assembling contradictory sources) paved the way for the Scholastic method later epitomized by Peter Lombard and Thomas Aquinas (vdoc.pub) (vdoc.pub). Abelard’s emphasis on intentional ethics influenced moral philosophy’s trajectory toward evaluating subjective culpability. Through the centuries, his personal story with Héloïse became legendary – to the Enlightenment, Abelard was a hero of free thought persecuted by dogmatists, and to the Romantics, their love and letters were an inspiration. Today, Abelard and Héloïse are often seen as emblematic lovers: they were even reburied together in a single tomb (now at Père Lachaise cemetery in Paris) in 1817 (commons.m.wikimedia.org) (commons.m.wikimedia.org). Within the Church, Abelard’s ideas on atonement (the “moral influence” theory that Christ’s love inspires our love) have gained appreciation as one valid perspective among others. His legacy is thus twofold: intellectual – as a progenitor of scholastic inquiry, and cultural – as half of one of history’s most famous couples. Abelard died in 1142 at the priory of St. Marcel near Chalon-sur-Saône; Héloïse had his remains moved to the Paraclete and upon her death in 1164 was buried beside him (plato.stanford.edu) (plato.stanford.edu). Their epitaph sums up Abelard’s life: “Nosce te ipsum” – know yourself. It is a fitting tribute that the man who wrote Scito te ipsum left a legacy encouraging the marriage of knowledge and self-reflection in the pursuit of truth.