This book--an erudite disquisition on the unsettling implications of medieval theories of perspectivist optics for the development of a coherent notion of the knowable self as explored through preaching and the confessional--is elegant and in the end often convincing. But nothing of what I as a reader found important in this treatment of the role of visual perception and visual error in late medieval theology is reflected in the title. Its choices of what topics to cover and which questions to answer are also often surprising. For instance, I picked up the book assuming it would discuss optical theory as an aspect of late medieval theology, and discovered that optics are not addressed with any concentration until page 75, and even then in a very specific sense that assumes a great deal of context on the part of the reader. The elliptical approach of the book towards its concerns and its resort to very tightly-defined examples of its points, a style of analysis that so often seems to avoid the goals the reader expects it to reach, will offer the greatest gratifications and frustrations to readers of the work who are not specialists in the history of science.
The book is organized in an introduction, five dense but well-written chapters that bear repeated re-reading, and a conclusion. Denery opens by discussing the general problem of the reliability of vision in the western tradition, noting both the gradual emergence of a new "scopic regime" toward the end of the high middle ages and the likelihood that visual error did not present the problems of self-knowledge for medieval authors that it did for Descartes and his successors. In light of this information, Denery notes the usefulness of establishing more reliable knowledge about late medieval thinking on visual perception as a means of enhancing discussions of the new way of seeing that seemed to emerge gradually all over Europe in the century leading up to the Renaissance. The resonance of new concerns with "seeing" were enhanced by developments inside the Dominican order, which stressed both preparation for active preaching among members and ever more frequent confession among the laity. These topics are the concerns of the first two chapters, which discuss how religious practices conducted in the absence of spectators in the modern sense "indefinitely deferred the formation of an individual or subject" (13). The medieval self that emerged was thus "infinitely complex and unknowable to all but God" (15). Denery explores these themes through thirteenth-century Dominican confessional and novice manuals to show the pressures placed on religious communities when their members were expected to be actively under way in the world and thus exposed to huge ranges of new audiences and contexts for their preaching. He then turns to confession--the increased desire for which was an effect of mendicants' successes--to show that the practices and techniques designed to meet the needs of individuals developing life narratives in order to confess their sins completely also undermined the possibility that these practices could ever be successful. Because self-knowledge was only obtainable in the presence of another, it could only be understood as a series of inevitably incomplete representations, of perceptions that could also be misperceptions. In chapter 3, Denery turns to the reception of Alhacen's perspectivist optics among thirteenth-century theologians and natural philosophers. Peter of Limoges' influential Tractatus moralis de oculo (1280) fused optics to religious life by articulating problems of the later in terms of the former. In his work, the mutual feedback between self- knowledge and seeing oneself ultimately makes the activity of confession uncertain, insofar as all late medieval optical theorists conceded the inevitability of visual error--debates of which are the chief focus of chapters 4 (on Peter Autreol) and 5 (on Nicholas of Autrecourt). Aureol's work explored the many pitfalls of visual perception, which has deception as "its central organizing principle" (135); Autrecourt, apparently in engagement with Aureol's concerns, rejects even the possibility of accurate cognition of evidence through seeing. Instead of merely complicating our perceptions, visual appearances stand decisively in the way of true knowledge of the world around us.
The strengths of Denery's monograph are many, not least the emphasis it places on our recognition of the role that natural philosophy played in late medieval theology and its reminder that medieval natural philosophers typically came to their subject as theologians. I found the idea of confession as a case study in visual epistemology thought-provoking and stimulating. That Denery can make his case so economically but nonetheless convincingly is envious. His journey through confession and penance from the standpoint of optics is also novel and effective; most specialists on late medieval piety will not have considered this perspective, which potentially adds an important element to understandings of the "penitential mood" of the late middle ages. In the context of Reformation history, debate has raged inconclusively for decades about the extent of individual insecurity about salvation, and Denery's evidence has challenging implications for the standpoint of many historical theologians, such as Sven Grosse, whose work on scrupulositas, not referenced by Denery, shows that the consolation and security offered in late medieval consolatory works was at the very least present and quite possibly sufficient to extinguish individual insecurities about confession. To a discussion of the implications of his research for this sticky problem is where I wish the book had gone after chapter 2, but Denery sets this question aside in a few sentences. Although my reaction stems from a theologically--rather than scientifically--minded stance that marks me as a potentially anomalous reader of his work, even so, the abrupt transition from this discussion to the treatment of Peter of Limoges, which one imagines was Denery's major concern, will be hard for readers not adept in history of science or natural philosophy to follow without flipping back to the introduction for a more explicit rehearsal of how Denery conceptualizes this relationship. Similarly, the end of the book read for me as a bit of a missed opportunity: Denery regularly points out the contrast in notions of self-knowledge and perception between his thinkers and Descartes, but resorts to an at-best oblique engagement with the vast and growing literature on the status of the self in the Renaissance and Reformation.
To resort to an optical metaphor, the sort of light this book resembles most greatly is the laser, which cuts through its intended objects quite precisely but leaves swathes of neighboring material untouched. On the one hand, the reader appreciates the tight argumentation; on the other, she wonders if the book is presenting the whole story; one the one hand, one appreciates the way Denery avoids broad attributions of causality to particular ideas; on the other, one wonders whether there is a direct relationship between some of the topics addressed. This quandary arises particularly with regard to Denery's discussion of Dominican preaching, which is treated primarily as an intellectual or epistemological activity as opposed to a social or pedagogical one. The impression one receives is that preachers and confessors developed a notion that self-knowledge was faulty primarily for philosophical reasons rather than as a consequence of quotidian engagement with disingenuous penitents. In general, the order is taken up somewhat in medias res; we wonder in the end if the desire for greater self-knowledge and the rush to the confessional was an effect or a cause of Dominican activity and its popularity, especially insofar as, at least at first, Denery attributes interpretations of visual analogies to religious practices rather than suggesting religious practices were the result of philosophical ideas (13). And some striking implications of Denery's subject are not touched upon, such as the relationship between actual spaces of the confessional in medieval Europe (when there was as yet no special restricted space ordained for the practice, at least for lay people) and his claim that encountering the self in confession was akin to encountering the other in an "inner house of conscience," a recurring Dominican metaphor that he addresses specifically.
Although Denery's book is not an easy read, readers who stick to it will be rewarded with a number of creative insights that should engender further thinking. That scholars interested in late medieval confession, preaching, and the self are not targeted in the title is surely a marketing error.