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Abelard, Peter (1079–1142)


Peter Abelard has been famous since the fourteenth century for his exchange of love letters with Héloïse, his former wife, written when he was a monk and she a nun. Nineteenth-century historians saw him as a rationalist critic of traditional Christian doctrine and a forerunner of modernity. More recently, Abelard's originality and power as a philosopher have come to be appreciated.

Abelard's working life splits into two main, slightly overlapping periods. From about 1100 until about 1125, his activity as a thinker and teacher revolved around the ancient logical texts available in Latin at that timethe so-called logica vetus ("Old Logic"). But from about 1120, Abelard started to become strongly interested in questions about Christian doctrine, to which he gradually came to give an increasingly ethical emphasis. The important works of the first phase of his career were thus the Dialectica (c. 11131116), a logical textbook, and the Logica Ingredientibus (c. 1119), commentaries on ancient logical texts (along with a shorter logical commentary, the Logica Nostrorum Petitioni Sociorum, from the mid-1120s). To the second phase belong his Theologia, mainly a philosophical investigation of the Trinity, which exists in three different, much altered versions: Theologia Summi Boni (1121), Theologia Christiana (c. 1125), Theologia Scholarium (c. 11331134); biblical commentaries, and a set of Sentences (c. 1134), which record his lectures on a wide range of theological topics; the Collationes (Comparisons), an imaginary dialogue between a Philosopher, a Jew, and a Christian (probably c. 1130); and the Scito teipsum (Know yourself!) or, as it is sometimes called, Abelard's Ethics (1138).

Although the division of his career into two phases was partly occasioned by his castration in 1117 (at the hands of ruffians hired by Héloïse's uncle, the canon of Notre-Dame), which put a violent end to his marriage, and his subsequent decision to become a monk of Saint-Denis, Abelard remained a teacher for most of his life. After studying with two of the most celebrated logicians of the time, Roscelin of Compiègne and William of Champeaux, both of whom later considered him an enemy, Abelard set up his own school and finally became the schoolmaster in Paris. He continued to teach as a monk of Saint-Denis and later, when he left that monastery to set up his own hermetic-monastic community. After a period as an unsuccessful reforming abbot of a remote Breton monastery, Abelard returned to the now numerous and flourishing Paris schools in the 1130s. He spent his final years at Cluny and its dependency, after his activity as a teacher was ended by his condemnation at the Council of Sens (1140).


The logica vetus included just two texts by Aristotle himself, the Categories and On Interpretation, along with the Isagoge (Introduction) to the Categories by Porphyry (c. 232305 CE), and texts by Boethius (c. 475c. 524 CE) on categorical and hypothetical syllogism, division, and topical inference. From this unpromising set of authorities, Abelard was able not merely to explore areas of formal logic untouched by Aristotle, but also to elaborate a whole metaphysics and semantics.

Ancient and medieval logicians worked in natural language, rather than devising a special logical symbolism. One of the hallmarks of Abelard's approach to logic was his awareness of the ambiguities in many ordinary sentences and the need to distinguish them carefully when constructing a logical argument. Abelard was not the first medieval logician to notice this point (Anselm of Canterbury, for instance, was an eleventh-century forerunner), but he placed an emphasis on it that would be taken up by many of his medieval successors. Consider, for instance, a sentence such as "Possibly the standing man sits." Abelard is quick to observe that it can be read in a composite sense (This is possible: that the man is standing-and-sitting ) or in a divided sense (The man is standing, and it is possible that he is sitting ). Although this distinction is made by Aristotle in his Sophistical Refutations, Abelard had already used it very widely in his Dialectica before he read it in the Aristotelian text.

Moreover, Abelard used this approach as the basis for devisingas Christopher Martin has showna genuinely propositional logic, to complement the term logic of Aristotelian syllogistic. In antiquity, the Stoics developed a propositional logic, and traces of their theory are found in Boethius's writings on topical argument and hypothetical syllogisms. Boethius, however, clearly neither developed a propositional logic nor understood it. His hypothetical syllogisms (for instance, "If it is day, it is light. It is day. So it is light") look like arguments in propositional logic, but Boethius takes them as being based on the relation between the terms day and light ; and he cannot grasp the negation of a conditional such as, "If it is day, it is light," except as the negation of one of the terms ("If it is day, it is not light"). By contrast, Abelard has a clear notion of propositional negation (It is not the case that: If it is day, it is light), and it governs his reconstruction of the theory of topical argument. For Boethius the theory of topics is a sort of logic for constructing real arguments on the basis of commonly accepted maxims, which range from basic logical principles to (fairly dubious) rules of thumb, such as "What the experts think about something is true." Abelard retains only those maxims which underwrite conditionals that are not just logically necessary, but where the sense of the consequent is contained in that of the antecedent (for example, Abelard accepts "Whatever is predicated of the species is predicated of the genus," on which is based, for instance, "If it is a man, it is an animal"). The resulting system of propositional logic turns out to be more like some modern connexive logics than classical modern propositional calculus.

Metaphysics and Semantics

Aristotle's Categories provided Abelard and his contemporaries with a basic metaphysics. It proposes that the items that make up the world are either substances, which exist independently, or non-substances, which exist only in dependence on substances; and that they are either particular or universal. For example, John Marenbon is a particular substance and man (in general) a universal one; the whiteness of John's skin and his rationality are individual non-substances, and whiteness and rationality (in general) are universal non-substances. Abelard, however, is a nominalist. Following, but exploring in more depth, a lead given by others, including Roscelin, he contended that everything which exists is a particular. There are no universal things, he argued, because to be universal a thing would have to be both one and shared between many in a way that is impossible. Abelard had, then, to show how the basic structure of the universe can be explained solely in terms of particular substance and non-substances.

Unlike many more recent nominalists, Abelard accepted that the best scientific description (Aristotle's, he thought) cuts nature at the joints: It is a fundamental truth, he believed, that some things are human beings and others dogs, and that human beings are human because they are mortal, rational animals. To be a mortal, rational animal, indeed, is to have the "status" of man, Abelard said. But, he quickly added, a status is not a thing. Every human, then, is alike in having his or her own particular rationality, mortality, and animality. But what about these particular non-substance things? They are, in Abelard's view, real items on an ontological checklist because, he says, it might have been the case that the particularity rationality R1 by which John is rational was the rationality by which Williamwho is in fact rational by rationality R2is rational, and vice versa; and so R1 cannot be explained away as just being John insofar as he is rational. The non-substance particulars are dependent, however, because they cannot exist except in some substance or other, and they cannot exist in one substance and then afterward in another. Just as Abelard has to explain what it is that makes John and William both human beings, he must explain too what it is that makes R1 and R2 both rationalities. But he does not, as might be expected, try to speak of a status of being rationalanalyzing rationality into certain patterns of behavior, for instance. Rather, he seems to admit, in all but name, that there is a universal rationality.

Abelard's nominalism also poses a semantic problem with regard to universal words. It is important to grasp that this problem is not one about reference. Once a kind-word is first imposed, it automatically refers to every particular which is really of that kind, even if the impositor himself has merely a vague or inaccurate idea of the internal structure which characterizes the species in question. (This feature, as Peter King [1982] has pointed out, brings Abelard's semantics uncannily close to the thought of contemporary philosophers such as Kripke.) By contrast, a word's signification is, for medieval authors in general, a causal, psychological notion: a word w signifies x by causing a thought of x in the listener's mind. The signification of "human being" in "John is a human being" is clearly universal: the x of which it causes a thought is a universal human being, not a particular one. But how can there be such an x, if every thing is particular? Abelard's answer is to say that universal words cause a mental image, a confused conception of, for instance, what humans have in common, which is not the image of any particular man. Such confused conceptions are not things, and it is these conceptions which universal words signify. The conceptions are not things, because they are not thoughts themselves (which Abelard would class as particular non-substance things), but the contents of thoughtsobjects in the world envisaged, to use an anachronistic expression, under a certain mode of presentation.

Abelard also had a theory about the semantics of sentences. A sentence signifies neither the things to which its component words refer, nor the thought they produce, but rather its dictum (meaning "what it says"). At first sight, Abelard seems to mean by dictum what modern philosophers call a proposition, and he does indeed characterize those logical connections that he understands propositionallyas, for example, between the antecedent and consequent of a conditionalas holding between dicta. But it is not quite clear whether dicta are truth-bearers or rather, like facts, truth-makers. Moreover, Abelard insists that dicta along with statuses and common conceptionsare not things. But whether he can coherently deny the reality of dicta, while at the same time using them to underpin his account of the workings of the universe, remains doubtful. Nonetheless, Abelard's metaphysics is bold and original, and it ranges into many areas other than those discussed here, such as parts and wholes, relations, the physical constitution of objects and their sensible properties, and the laws of nature.


Like any Christian thinker, Abelard held that every detail of world history is providentially ordained. Unlike the great theologians of the thirteenth century, such as Thomas Aquinas and John Duns Scotus, he did not accept that God has any freedom in choosing what the course of providence should be: God, he argues, must choose whatever is best to happen, and that, he believes, leaves no space for alternatives. Yet there is room, Abelard thought (contradicting the Platonizing tradition of Augustine and Anselm) for the existence of genuinely evil things, becauseas he explains, citing the distinction between things and dicta it is good that there is evil.

If God ordains the universe so that every human action, good or evil, contributes to the best providence, it is clear that ethical judgment cannot be based on consequences. Abelard is very often seen as a moral theorist who, rather, concentrates entirely on intentions, and subscribes to a subjective view of morality. Both aspects of this characterization need qualification. Following Augustine's lead, almost all medieval thinkers based moral judgment on intentions. For instance, Abelard's immediate predecessors and contemporaries saw sinning as a stage-by-stage process of intendinga person begins to sin once he entertains a temptation to perform a forbidden act; as he thinks about it with pleasure and plans how to put it into effect, the sin becomes graver, and it is more serious still when he actually performs the act. By contrast, for Abelard someone is guilty of sinning when, and only when, he consents to the sinwhen he is ready to perform it and will do so unless thwarted. Up until that moment, he is not guilty, and, once that moment is reached, his guilt is complete: performing the act will not increase it.

Abelard's account of what determines whether an action is sinful or not seems at first sight to be subjective. A person sins, he says, by showing contempt for God. It sounds, from this definition, as if it is the mere subjective state of someone's mind, and not what he does or plans to do, that makes him a sinner. But, for Abelard, one shows contempt for God precisely by consenting to an action one knows is divinely forbidden. Sinners do not usually want to perform a forbidden action because it is forbidden; rather, they perform it in spite of the fact that God forbids it, and very often with the fervent wish that it were licit. Moreover, he does not think that it is a matter of guesswork to decide which acts God forbids. Christians and Jews have scriptural revelation to guide them; but, in any case, Abelard believed, all people in all places and in all times, apart from children and the mentally incapable, are able to grasp natural law, which teaches them the fundamental rules for behavior ordained by God. Abelard would not hesitate, therefore, to say that, for example, it is and was always wrong for a mentally normal adult to commit adultery (unless, in some way, he is unaware that it is in this case adultery) because he could not fail to know that adultery is divinely forbidden and that, therefore, it shows contempt to God to perform it.

Abelard's account of acting well is less fully developed than his treatment of sinning. He takes over a list of four virtues (ultimately from Plato's Republic ) from Cicero: prudence, justice, courage, and temperance. He does not, however, use these virtues to provide a view of the good life for human beings. Rather, he sees justice as the central virtue, by which a person acts in accord with God's commands as known through revelation or natural law. Prudence is a precondition for being just, but not a virtue itself. Courage and temperance are props of justice. A person may be deflected from just action by fear or by desire for pleasure; courage makes him stand firm, despite what threatens him; temperance makes him resist the blandishments of pleasure.

As this description suggests, Abelard tends to think of morally good action as a hard-won victory over sinning, which is usually the easier or the more pleasant choice. Yet he also wants to insist that there is something deficient in goodness about actions which, although carried out from excellent motives, fail to achieve their intended good effect; as, for example, if a person works hard in order to provide for the poor or the sick, but his plans are never realized. Abelard's ethical theory is further complicated by a somewhat unexpected twist. He believes that judgments made by human judges should be based on a utilitarian evaluation of the punishments given. A woman who entirely unintentionally smothers her baby (whom she was trying to keep warm) should be punished severely, although she has committed no sin, so as to discourage others from making the same mistake.

Philosophy of Religion

Modern interpreters of Abelard tend to play down any tension between his rationalism and Christian belief: He used the tools of his logic, they say, to analyse Christian doctrines and criticize heretical distortions of them, but he was fully willing to accept the ultimate mysteriousness of doctrines such as the Trinity. Yet there is good reason to see Abelard's main project in the works of his last decade as being the presentation of a rationalized Christianity, which in important ways did not accord with the accepted beliefs of his time.

Abelard's conception of a universal natural law was not merely a foundation for his ethical theory. People at all times and in all places, he believed, have been able to grasp the fact the God exists, and that God is triune. Supposedly pagan sources, such as Plato, the Sibylls, and the writings attributed to Hermes Trismegistus, provide better testimony, he believes, to the Trinity than anything in the Old or even the New Testament. Although Abelardunder pressure to conform to an orthodoxy which, as it turned out, he was in any case accused of infringingmight accept a certain element of inexplicable mystery in the doctrine of divine triunity, he elaborated in the different versions of his Theologia a complex theory of sameness and difference, which seems to have been designed to explain in terms of logic how something can be three and yet one. And he considered that God's triune nature emerged just from thinking about the attributes an omniperfect being must have: "For God to be three personsFather, Son and Holy Spiritis," he explains at the beginning of the Theologia Summi Boni, "as if we were to say that the divine substance is powerful, wise and benign. " This attitude was part of Abelard's general, though nuanced, rejection of there being anything praiseworthy in the acceptance by faith of truths that are not understood, and of the limited function he gives to revelation. For most of his contemporaries, the Jews, to whom the Old Law had been revealed, were far closer to a grasp of the truth than the ancient pagans. For Abelard, the pagan philosophers, without revelation but using natural law, were able to live highly virtuous lives and to reach a better understanding of God than most of the Jews.

Abelard did not, however, think that every important theological truth could be grasped by reason, without revelation. In particular, only by revelation can people know of Christ's life and his death, and without this knowledge, he thought, no one can be saved. But Abelard went on to argue that God would reveal what was necessary for salvation to anyone who lived well, and also to give a rationalistic explanation of why it was necessary to know about Christ's crucifixionbecause it set an example of love, indispensable for being able to overcome temptations. Similarly, while Abelard broadly accepted the biblical accounts of heaven and hell, he was one of the few medieval thinkers to insist that they should not be interpreted literally.

After Abelard

One of the schools of later twelfth-century philosophy, the nominales, probably consisted of Abelard's followers. But, apart from his letters to Héloïse, Abelard was not one of the authors who was much read after 1200. Elements of his approach to logic were absorbed into the developing medieval curriculum, although many of his subtlest ideas seem never to have been used. The type of doctrinal problems raised by him influenced the Sentences, written by Peter Lombard in the 1150s, and through this work, which became the standard textbook, the whole tradition of later medieval theology. Abelard's effect on the positions and arguments they developed was very limited, however, because the university theologians had their outlook formed by a reading of the whole range of Aristotle's philosophy and the Arabic commentary tradition. In many ways, however, Abelard's approach to metaphysics and the philosophy of religion, with its basis in logical and linguistic analysis, is closer to today's philosophical tastes than the grand systems of the thirteenth and early fourteenth-century philosophers.

See also Aristotelianism; Logic, History of: Ancient Logic; Logic, History of: Medieval (European) Logic; William of Champeaux.


works by abelard

Selected Latin Texts

Petri Abaelardi Dialectica, edited by Lambertus M. de Rijk. 2nd ed. Assen: Van Gorcum, 1970.

Petri Abaelardi opera theologica IIII, edited by Eligius Buytaert (and Constant J. Mews, vol. III). Turnhout: Brepols, 1967. Corpus christianorum, continuatio mediaeualis 13 (including the Theologia in its different versions).

Peter Abaelards philosophische Schriften, I. 3, edited by Bernhard Geyer. Münster: Aschendorff, 1927 (Beiträge zur Geschichte der Philosophie und Theologie des Mittlalters 21). Logical commentaries.

Sententiae magistri Petri Abaelardi (Sententie Hermanni), edited by Sandro Buzzetti. Florence: La nuova Italia, 1983.

English Translations

Five Texts on the Mediaeval Problem of Universals: Porphyry, Boethius, Abelard, Duns Scotus, Ockham, edited by Paul V. Spade. Indianapolis and Cambridge: Hackett, 1994. Extract from Logica Ingredientibus.

Peter Abelard's "Collationes," edited by J. Marenbon and G. Orlandi. Oxford: Oxford University Press, 2001. Latin and English.

Peter Abelard's "Ethics," edited by David E. Luscombe. Oxford: Oxford University Press, 1971. Latin and English.

works about abelard

Brower, Jeffrey E., and Kevin Guilfoy, eds. The Cambridge Companion to Abelard. Cambridge, U.K., and New York: Cambridge University Press, 2004.

Clanchy, Michael. Abelard: A Medieval Life. Oxford: Blackwell, 1997.

De Rijk, Lambertus M. "Peter Abelard's Semantics and his Doctrine of Being." Vivarium 24 (1986): 85128.

King, Peter O. "Peter Abailard and the Problem of Universals." PhD diss. Princeton University, 1982.

Marenbon, John. The Philosophy of Peter Abelard. Cambridge, U.K.: Cambridge University Press, 1997.

Martin, Christopher J. "Embarrassing Arguments and Surprising Conclusions in the Development of Theories of the Conditional in the Twelfth Century." In Gilbert de Poitiers et ses contemporains, edited by Jean Jolivet and Alain De Libera, 377400. Naples: Bibliopolis, 1987.

Martin, Christopher J. "Logic." In The Cambridge Companion to Abelard, edited by Jeffrey E. Brower and Kevin Guilfoy, 158199. Cambridge, U.K., and New York: Cambridge University Press, 2004.

Mews, Constant J. Abelard and Heloise. Oxford: Oxford University Press, 2005.

Mews, Constant J. Peter Abelard. Aldershot: Variorum, 1995.

Tweedale, Martin. Abailard on Universals. Amsterdam and New York: North Holland, 1976.

John Marenbon (2005)

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