Lukács, Edit Anna and Michalowska, Monika (eds.). Calculating Ethics in the Fourteenth Century. Leiden: Brill 2024, x + 341 pp.

This volume sheds light on the use of quantitative measures in ethical discussions among fourteenth-century theologians who were, in various ways, influenced by or connected with the Oxford Calculators (a loosely defined group whose central figures typically include Thomas Bradwardine, William Heytesbury, John Dumbleton, and Richard Swineshead). These thinkers applied mathematics to the study of motion, particularly the use of latitudes (latitudines), often appealing to a mean, to measure changes in velocity. They were concerned with different methods of calculating change. This volume seeks to trace their influence on emerging ethical discussions involving such topics as the acquisition of virtue, the intensification of habits, and the efficacy of willing.

The volume’s nine essays do not treat these central figures directly but instead focus on Walter Burley, Richard Fitzralph, Richard Kilvington, John Buridan, Robert Halifax, Robert Holcot, Peter Ceffons, and John Ripa. Kilvington has only recently received much scholarly attention, particularly through the work of editor Monika Michalowska. Unlike figures such as Bradwardine, Kilvington was not edited in early modern editions, and is not often explicitly cited by later authors. Nevertheless, Kilvington clearly was a Calculator and wrote extensively on ethics. Burley, Holcot, Fitzralph, and Halifax either helped prepare the way for, or were themselves in some measure part of, this intellectual movement. The remaining figures were contemporaries who worked on similar problems and may have been influenced by the Calculators’ approach. The volume contains an introduction, six historical chapters, a lengthy study and edition of a question by Peter Ceffons (which together occupy roughly one-third of the book), and a concluding chapter on the differences between medieval and modern approaches to measuring psychological qualities.

Chapter One, the introduction by editors Monika Michalowska and Edit Anna Lukács, explains the purpose of the volume and provides relevant background. The editors highlight Richard Kilvington’s application of Calculator methods to ethical issues, focusing on three key features. First, Kilvington employs a secundum imaginationem procedure, in which hypothetical scenarios are used for argumentative purposes. Second, he applies the Calculators’ notion of latitude to the measurement of virtue and vice. Third, he draws on the Calculators’ treatment of motion and proportional calculation to argue for instantaneous volition and enjoyment. The editors suggest that these three features were characteristic of fourteenth-century thought, and some of the subsequent chapters do refer to them. However, these themes are only loosely present in several of the essays, and it is unclear how the later chapters were selected or organized to illustrate the editors’ goals.

Three chapters discuss the acquisition and growth of habits such as the virtues. In Chapter Two, Mark Gensler considers “Walter Burley on Moral Change.” He compares Burley’s account of the intension and remission of accidental forms (such as habits) with earlier views held by Godfrey of Fontaines and John Duns Scotus. Godfrey argued that in qualitative intensification, a new form replaces the previous form entirely. In contrast, Scotus held that such intensification involves adding new parts to the existing form. Burley holds that various acts contribute to the eventual acquisition of a habit, such as a virtue, at a higher degree. The most perfect degree of the habit is acquired by a final act, which is prepared by prior ones. However, Burley does not attempt to quantify the process. Gensler aptly notes: “What appears interesting in some of Burley’s boringly repetitive arguments is his insistence that the acquisition of degrees by qualitative forms does not mean that these forms can be treated quantitatively” (43).

Chapter Four is, in some respects, the heart of the volume. Monika Michalowska examines Kilvington’s account of ethical change, particularly his application of concepts of degrees and physical motion to ethical phenomena. However, Michalowska appears to conflate two distinct issues. In some places (e. g., 78–81), she focuses on degrees among the effects caused by an action, especially in the context of practical reasoning and the assessment of outcomes. In other passages, she addresses the acquisition and perfection of virtue in degrees – a quite different topic.

In Chapter Five, Valerie Buffon begins by surveying earlier medieval discussions on whether a single act can generate virtue, before turning to a more sustained analysis of John Buridan’s treatment of virtue acquisition. She provides a helpful list of thirteenth-century distinctions concerning the intensity of action. Her treatment of Buridan seems related to his account of the interconnection of the virtues, though this connection is not explored in detail. There are, however, some imprecisions in her analysis. First, she implies that all the thinkers she surveys share a similar understanding of disposition and habit, which is not the case. Second, she claims that Buridan is concerned with “the newly minted concept of gradus” (131), but it would have been helpful to consider William of Ockham’s earlier account of the five gradus of virtue, as well as antecedents in figures such as Henry of Ghent. Finally, Buffon seems to misunderstand the boundary between philosophy and theology when she suggests that Aristotle’s text implies that theological virtues are acquired by human action (128–129). This interpretation is problematic, given that theological virtues, by definition, lie outside Aristotle’s framework.

Three chapters examine fourteenth-century figures in relation to other historical periods and in the broader context of faith and reason. In Chapter Three, Michael Dunne explores Richard Fitzralph’s discussion of whether contradictory appetites or passions can exist in the will. He offers a helpful account of Fitzralph’s connections to Oxford, making at least some link to the Calculator tradition plausible. Dunne attempts to show that the problem of contradictory appetites has roots in both Sacred Scripture and Aristotle and is later taken up by Martin Luther. These historical claims are intriguing but would benefit from more conceptual precision and historical development. A particularly interesting feature of Fitzralph’s treatment is that while we possess his formulation of the problem, his solution is not extant. Dunne connects Fitzralph’s presentation of the issue to different solutions given by Adam Wodeham and John Buridan.

Chapter Six, by co-editor Edit Lukács, examines Robert Halifax’s account of supererogation. Lukács argues that supererogation is a particularly Christian concept, associated with ideals such as martyrdom and virginity. She references various Protestant and contemporary accounts of what supererogation entails. Unfortunately, it is unclear whether she intends the term to apply only to heroic or exceptional virtue (such as martyrdom) or more broadly to any good act that exceeds strict legal obligation. This distinction is important. For example, one might be morally required to choose martyrdom over apostasy, in which case the act, though heroic, is obligatory. In contrast, small acts of charity, while not required, may still be more perfect. Lukács does not clearly articulate this distinction between obligatory heroic acts and perfect acts that are not obligatory, though it seems to be noted in Halifax’s cited texts (148). Only the latter seem obviously supererogatory. More productively, she draws attention to Halifax’s emphasis on conatus (effort or striving) as a key factor in moral merit.

In Chapter Seven, Pascale Bermon discusses Robert Holcot’s account of faith in relation to Solomon Asch’s famous conformity experiments, which demonstrate how individuals are often swayed by the beliefs of others. Holcot investigates in what way faith can be meritorious. Asch, by contrast, examines why people adopt beliefs in the face of social pressure. Bermon does not clearly distinguish Holcot’s concern with meritorious belief from Asch’s interest in conformity under social pressure. For instance, Holcot explains that faith does not arise from sensation but from authority. He contrasts belief based on witness testimony with belief based on sensation. Asch makes a different distinction between peer pressure on the one hand, and evidence and observation on the other.

Chapter Eight consists of a forty-four-page article and a seventy-one-page edition of a discussion by the French Cistercian Peter Ceffons. The essay addresses disputes over proportionality and measurement. Fourteenth-century thinkers used geometrical reasoning to analyze proportions of change. They also explored in this context proportions of proportions, sparking debates about infinity and measurement. These geometrical considerations gave rise to a range of disputed opinions — for example, whether there could be infinite grades within and between species, and whether degrees should be measured from the highest or lowest member of a given series. Ceffons’s text is highly geometrical and primarily concerned with these questions of infinity and, to a lesser extent, perfection, with only a brief aside addressing habits. The thematic connection between Ceffons’s text and the volume’s focus on Calculator-influenced ethics is tenuous, as his work primarily addresses geometrical proportionality rather than ethical applications. Nevertheless, the arguments are intellectually engaging, though I often found it necessary to draw my own diagrams and look up specialized geometrical terminology to fully grasp them. The historical and philosophical significance of Ceffons’s text remains uncertain, particularly given its survival in only a single manuscript.

In Chapter Nine, Simon Kemp contrasts fourteenth-century and contemporary efforts to measure psychological qualities. He examines modern attempts to quantify traits such as disapproval of crime and agreeableness, and notes that medieval authors did not pursue such forms of psychological measurement. Kemp suggests several possibilities: that the application of their theories to these domains may not have occurred to them; that they may have judged such applications to be unhelpful for ethical analysis; or that they may have anticipated contemporary critiques of quantifying inner states. He concludes both his essay and the volume by observing: “The fourteenth-century approach was generally more theoretical and perhaps more cautious than the present-day one, which has sometimes tended to gloss over difficult theoretical issues in favor of yielding information that appears useful” (328).

The essays in this volume offer valuable insights into fourteenth-century philosophy but do not consistently support the introduction’s claim that the Oxford Calculators made significant contributions to ethics or that they are central to the history of philosophy. Several chapters display conceptual imprecision and limited engagement with the relevant historical background. Nonetheless, the volume deepens our understanding of lesser-known figures and suggests promising directions for further research.