Late medieval writers argued over the relationship of faith to reason. Followers of the via antiqua, including Thomists, defended a close relationship of theology to philosophy. Followers of the via moderna believed logic could not demonstrate the truth of scripture. Nicholas of Cusa was engaged with these issues in his own way. As K. M. Ziebart notes in the introduction to this book, Cusanus’s contribution is not easy to interpret. Modern authors have differed widely interpreting his ideas on faith and reason. Part of the problem lies with Cusanus’s effort to intellectualize faith without abandoning the truths found in scripture. Ziebart’s study follows controversies in which Cusanus was engaged and the relationship of faith to reason in his sermons. Among the matters studied is his attitude toward Aristotle, which was more positive than we usually are led to believe.

The heart of Ziebart’s book is the account of two controversies in which Nicholas was involved. Two men, Johann Wenck and Vincent of Aggsbach, attacked him from opposite angles. Wenck regarded Cusanus as undermining rational thought and Church discipline, while Vincent thought the cardinal was making mystical theology too intellectual. Cusanus was attacked with venom not just for his theological opinions, but for having abandoned the Council of Basel (1431–49). As a former conciliarist who became a cardinal, Nicholas was regarded as a traitor to conciliarism and a foe of reform.

Johann Wenck, a Heidelberg theologian who regarded himself as a champion of orthodoxy, accused Cusanus of undermining Church discipline by emphasizing direct mystical experience. Wenck regarded him as sharing the errors of Meister Eckhart and the Beghards. Wenck also thought Cusanus was not grounded sufficiently in scripture. His philosophical criticism of Nicholas’s idea of “the coincidence of opposites” was a defense of Aristotle’s principle of noncontradiction. Cusanus answered Wenck’s arguments, but he also was aware of the need to avoid the appearance of collapsing the distinction between creator and creatures. The cardinal also was careful to argue, using the latest translations of Aristotle, that he was not undermining the philosopher’s authority. This debate also forms a background to Nicholas’s Idiota dialogues, which argued for a new theological method to replace the sterility he saw in contemporary Scholastics like Wenck.

Vincent, a Carthusian, argued for a more affective theology of mystical ascent, which he regarded as the most accurate interpretation of the Dionysian tradition. Vincent attacked not just Cusanus, but Marquard Sprenger and even Jean Gerson for intellectualizing mystical theology. This theological exchange soon involved the monastery of Tegernsee, with whose abbot and prior Cusanus corresponded. (The prior’s work praising learned ignorance, not Cusanus’s own writings, was Vincent’s original point of attack.) Nicholas, answering Vincent, defended the intellectual component of mystical theology, and he tried to teach this through the image of an all-seeing icon in his De visione Dei. Nicholas said that one had to seek before one could love, placing the intellectual prior to the affective. One notes here that Cusanus was admired at Tegernsee, but the monks were confused by his ideas. They were more at home with the affective approach, which triumphed in circles of reformed German monks.

The chapter on the sermons is more scattered, because it excerpts from several texts written years apart. Nicholas said in many of these accounts of his preaching that faith stimulated the intellect. What it stimulated was in the higher faculty, the intellect, in which it already resided in potentia. This appeal to higher rationality went together with the argument that Aristotle had argued well about reason but had not risen to that higher realm. Nor did the Aristotelian sect of Cusanus’s day, men like Wenck, understand this need for experience. Moreover, Nicholas saw this faith in potentia as universal, which casts light on the irenic viewpoint adopted in De pace fidei. Ziebart finds in these texts, as in the controversies, a striving, a tension between elements of faith and intellect; and that tension was not always successfully brought into harmony. An irony of these debates is the way in which the critiques of Wenck and Vincent struck at the same problems in this synthesis even though they started with different objections to Cusanus’s efforts to revitalize the theologies of his day.