Back at Saint Denis, Abelard applied himself to the monastery’s renowned library. The sizable library and scriptorium (the writing room where monks copied texts by hand) at Saint Denis offered him an enhanced opportunity to access a comprehensive collection of texts that had influenced the development of religious doctrine, especially the Latin church fathers; the collection at Saint Denis exceeded even that of the school at Notre Dame in Paris. These authorities had shaped religious thought since the earliest days of the church, forming a body of scriptural interpretation that was second in authority only to the Bible itself. Abelard’s command of these works likely was started at the extensive library of Saint Denis; his facility with these authorities is demonstrated clearly in his famous work Sic et non (Yes and No), which he probably began at Saint Denis. This work shows Abelard’s logical mind striving to resolve the inevitable contradictions among these authorities. In effect a work of comparative scholarship, Sic et non presents sets of disputed theological and scriptural propositions and then puts forward quotations and citations arguing contrasting positions—hence, the title Yes and No, or, as we might say today, “on one hand, but on the other hand.” Abelard proves, and then disproves, about 158 questions by citing the church fathers, scripture, church councils, and reason. For instance, he proposes a problem, such as “that God can do all things and against this,” and then systematically presents authorities supporting each side of the proposition. Abelard writes in the preface that his purpose is not to undermine authority by pointing out contradictions, which can arise from any number of benign reasons such as words with different meanings, shifts in meaning when texts are taken out of context, or even scribal errors. Abelard does not try to reconcile the conflicting authorities, and Sic et non is, effectively, a sort of notebook in which he has collected sentences to illustrate two sides of difficult questions. It seems likely that following his condemnation at Soissons, Abelard realized that henceforth he would have to support his arguments not simply with logic and reason but with past authorities’ opinions as well—in effect, precedent.
Abelard describes in his Historia how once again he invited controversy when he disputed the identity of the presumed founder of the monastery of Saint Denis. Saint Denis was among the most prestigious monasteries in France, owing in large part to its presumed illustrious founder. It was believed that a third-century bishop of Paris, Saint Denis, was martyred in 270 and the abbey of the same name was founded on the site where the famous martyr was believed to have been buried. Over time, the martyred saint came to be known as the patron saint of France, and his tomb became an important pilgrimage site, generating considerable income, as well as prestige for the monastery. The name Denis is rendered in Latin as Dionysius. In the Middle Ages, knowledge of ancient history often was quite sketchy, and Dionysius the early bishop came to be confused with another famous Dionysius from the Acts of the Apostles. This Dionysius was converted to Christianity by Saint Paul and then believed to have become the first bishop of Athens, the site of his conversion. In fact, the two were separated by more than two centuries, but the misidentification endured. The situation was complicated further by a third Dionysius, this one known today as an anonymous theologian and philosopher from the late fifth or early sixth century called Pseudo-Dionysius the Are-opagite, but in Abelard’s day he was believed to be the same Dionysius who was converted by Saint Paul. Therefore, medieval scholars had conflated the first-, third-, and sixth-century Dionysiuses as the same person. Abelard, who had been working his way through Saint Denis’s extensive monastic library, came across a sentence in a work called The History of the English Church and People (by the eighth-century English scholar known as the Venerable Bede) that he claimed contradicted the monks’ belief that Dionysius had been the bishop of Athens. To the annoyance of the monks, Abelard claimed that Bede had placed Dionysius not as the bishop of Athens, but as the bishop of Corinth. The outraged monks claimed their belief was based on the findings of their ninth-century abbot Hilduin, and they flatly declared that Bede was a liar. Abelard, now most willing to rely on authority to support his position, asserted that Bede carried much more weight than Hilduin and was recognized by the entire Church. As the dispute continued to grow, Adam the abbot of Saint Denis viewed the incident as an attack on France and seemed to be preparing to send Abelard before the king on a charge of treason. Abelard writes in his Historia that he endured the blows of fortune and the wickedness of the monks, and, declaring that the entire world had conspired against him, he fled Saint Denis in secret under cover of night, resolving to remove himself from France (the Ile-de-France).