A monument of the early history of Thomism is the wide-ranging Arguments Defending the Theology of St. Thomas Aquinas (Defensiones theologiae Divi Thomae Aquinatis) composed by the French Dominican Johannes Capreolus (1380–1444). Capreolus authored this massive work to defend the philosophical and theological system of Thomas Aquinas against a barrage of criticisms offered by many theorists in the century and a half after Aquinas's death. In the course of 190 quaestiones, Capreolus presented objections from Peter Auriol, Duns Scotus, and Henry of Ghent, among others, and then furnished replies ad mentem Thomae. He began the work in 1407 at the University of Paris at the request of his Dominican superiors, finally bringing it to completion two and a half decades later in Rodez in 1432, but it was not printed for another half-century. The Defensiones stands as the earliest comprehensive presentation of Thomistic philosophical and theological thought, and in light of his achievement Capreolus bears the honorific title Princeps Thomistarum or “Prince of Thomists.” In later decades Capreolus's masterwork became a sourcebook for Thomistic humanists of the Italian Renaissance as well as Catholic theologians of the Counter-Reformation. The Defensiones is strongly polemical; in it Capreolus defends the doctrines of Aquinas while attacking those who have criticized various points of the Thomistic system. The force and energy that pervade the work have led one commentator to characterize Capreolus as “a good representative of the Thomist school at war.”

The systematic investigation of whether moral dilemmas exist is often seen as an achievement of modern or contemporary philosophy, but it is in medieval philosophy that the subject is first substantively analyzed. The narrative here has offered a sampling of these medieval debates, and along the way the principle of the lesser evil has emerged as central to these discussions. The foremost defenders of the existence of moral dilemmas in the Middle Ages invoked the principle as a guide for action, arguing that agents should strive to minimize wrongdoing when its complete avoidance is impossible. Counted among the defenders of both the existence of moral dilemmas and the permissibility of the principle of the lesser evil are some of the great thinkers of the medieval period, including Gratian, William of Auxerre, and the Franciscan authors of the Summa Halesiana, among others. Throughout these debates, the authority of Gregory the Great was evident, as he continued to cast a long shadow throughout discussions of moral dilemmas even to the time of Capreolus in the fifteenth century.

Not all medieval moral theorists were promoters of moral dilemmas, however. The glossators on Gratian's Decretum denied their existence, offering arguments similar to Aquinas's later denial of situations of perplexity simpliciter. Absent from Aquinas's presentation, however, was the glossators' forceful assertion that dilemmas are simply illusory and merely the result of the foolishness of moral agents. Aquinas's most distinctive contribution to medieval moral dilemma theory was his strict separation of innocent-agent dilemmas from prior-fault dilemmas.

The detailed remarks concerning moral perplexitas offered by the twelfth- and thirteenth-century commentators of the Glossa ordinaria on Gratian's Decretum should not suggest that the field of canon law was the primary locus for theoretical consideration of moral dilemmas in the Middle Ages. While canon law was the earliest discipline to regularize discussion of moral dilemmas among its practitioners, largely because of the subject's inclusion in Gratian's influential textbook, a parallel situation occurred among practitioners of theology in the thirteenth century for two reasons. First, the appearance of formal treatments of perplexitas within some early influential summae theologiae or “summaries of theology” insured that students of the period would consider the subject. Secondly, the gradual adoption of the university practice of commenting on Peter Lombard's Sententiae also helped, as Lombard's discussion of conscience in the second book of that work became the standard occasion for considering cases of perplexitas involving erroneously formed consciences. While Lombard himself didn't use the term perplexitas in that discussion, many of his commentators did, including such major figures as Thomas Aquinas, Bonaventure of Bagnoregio (1217–74), and John Duns Scotus (1266–1308). This increase of interest in perplexitas, particularly among Parisian theologians of the thirteenth and early fourteenth centuries, was not of course without precedent. The previous chapter examined Gregory the Great's attention to the subject several centuries earlier in his Moralia in Job, a text that was quite influential for Gratian.

Is moral wrongdoing ever genuinely unavoidable? That is, will anyone ever experience real conflicting obligations at a given moment and thereby be compelled to act wrongly? This study considers several medieval theorists who dealt with the question of whether moral dilemmas are part of the moral life. As it is often assumed that serious theorizing about moral dilemmas was first achieved in modern philosophy, only to be refined further by contemporary thinkers, this book analyzes a rather neglected part of the history of Western ethical thought. The common view assumes that during the medieval period all moral theorists adhered to the maxim “ought implies can.” In contrast to that view, this book identifies medieval adherents to “ought but cannot.” Several medieval thinkers not only wrestled with the problem of reconciling the experience of moral conflict with the widespread assumption that no one should ever be forced to do wrong, but they also propounded their solutions with a level of sophistication that may be surprising to present-day philosophers. In light of these overlooked medieval contributions, the history of moral dilemma theory must be re-written. This book discloses that much of what seems particular to twentieth-century moral theorizing was quite well known long ago.

The present volume offers a sampling of these medieval debates, with particular attention to the diversity of examples of moral dilemmas central to those discussions. Many of them are surprisingly vivid, extraordinary, and at times quite shocking.

It is a pleasant task to thank those who have assisted me along the way. At Cambridge University Press, Beatrice Rehl first expressed interest in the project and Hilary Gaskin carefully guided the manuscript through the review process. Joanna Garbutt helpfully answered many queries, and Jodie Barnes and Anna Zaranko expertly oversaw the production and copyediting phases of this book. The two anonymous reviewers for the Press gave valuable comments.

My home institution provided material support in the form of a 2007 summer research grant and a 2010 fall sabbatical. Colleagues Lawrence Masek, Matthew Ponesse, and Perry Cahall read chapter drafts and offered insightful criticisms in addition to welcome company. On various occasions I have presented versions of chapters, and I am grateful to audience members for their questions and comments. In this regard I owe thanks to William Starr, Gregory LaNave, Carl Still, Brian Shanley, OP, John Knasas, Ed Houser, Mary Catherine Sommers, Christopher Martin, John Hittinger, Michael Waddell, John Finnis, James Jacobs, Nicholas Rescher, Michael Ross, Joseph Murphy, SJ, Jeffery Nicholas, W. Matthews Grant, John Simmons, Timothy Yoder, and Michael Henry.

The librarians at Ohio Dominican University's Spangler Library have been quite helpful, especially Jim Layden, Cathy Kellum, Evelyn Burns, and Joshua Alvarez. I am also grateful to Peter Veracka and Michelle Brown at the Wehrle Library of the Pontifical College Josephinum.

The Philosophy Documentation Center granted permission to incorporate revised excerpts of three previously published articles into the fourth and fifth chapters of this book.

Among the truths designated by Thomas Aquinas as self-evident (per se nota) belongs a class of propositions promoted as the foundation for ethical reasoning. Aquinas is confident that all agents possess at least a subset of these true propositions and regularly employ them in ethical decision-making. He identifies the production of such basic ethical propositions or first principles with the habit of synderesis. This habit of synderesis for practical reasoning is parallel to the habit of understanding (intellectus) for speculative reasoning, as both habits supply self-evident first principles for arguments in their respective domains. Synderesis supplies general truths as major premises for practical syllogizing, and intellectus does the same for theoretical or speculative syllogizing. While Aquinas's best-known example of a self-evident principle of practical reasoning, “good is to be done and pursued, and evil is to be avoided (bonum est faciendum et prosequendum, et malum vitandum),” is famously asserted in the discussion of natural law in the Summa theologiae and subject to much discussion among twentieth-century Thomistic commentators, it is not the one to which Aquinas gives the most analysis throughout his writings. Instead, the first principle of practical reasoning most extensively discussed by Aquinas is “The commandments of God are to be obeyed.” This principle, which for convenience can be referenced as the Divine Command Principle (hereafter, DCP), is defended in works throughout the span of Aquinas's writing career, yet it has largely been ignored by present-day commentators seeking to set forth Aquinas's philosophical ethics.

At the venerable age of seventy-five, the long-bearded philosopher Raymond Lull (c. 1232–1316) boarded a ship from his home in Majorca and sailed across the Mediterranean Sea to the North African Saracen city of Bougie. Upon disembarking, Lull immediately went to the main square of the city and began shouting wildly in Arabic. The Vita coaetanea records his words as, “The Christian religion is true and holy and acceptable to God; the Saracen religion, however, is false and full of error, and this I am prepared to prove.” The spectacle of a blaspheming foreigner drew the attention of the town's senior religious leader, who gave orders that Lull be brought before him. Shortly thereafter Lull subjected him to an exotic disquisition that employed various subtle Neoplatonic metaphysical distinctions. Baffled by this display, the religious leader ordered Lull's immediate imprisonment. The angry assembled crowd then seized Lull, beat the old man with fists and sticks, forcefully dragged him by his beard, and then locked him away in the sewer pit of a thieves' jail “where for some time he led a painful existence.” After an incarceration for a year and a half, Lull was expelled from the city and placed on a ship for Genoa, but when it was ten miles offshore from the port of Pisa a violent storm arose and capsized it.

Gratian is considered the founder of the scientific or systematic study of canon law on the basis of his influential synthetic work, the Decretum. An early section of that book deals with moral dilemmas, and this chapter will examine its argumentation and early reception. While the Decretum is well known, the same cannot be said of the details of its author's life. The amount of legend that surrounds the twelfth-century jurist is inversely proportional to the verified facts about him. If one listens to the former, one will hear that Gratian was a monk, either Benedictine or Camaldolese; that he resided at the monastery of Saints Felix and Nabor in Bologna and taught canon law there; that he was the brother of the Parisian theological master Peter Lombard; that his first name was Franciscus (or perhaps Johannes); and that during his ecclesiastical career he rose to the rank of abbot, bishop, or even cardinal. All of these claims have been found to be largely unconfirmed and traceable to questionable sources at times centuries removed from Gratian's day. What is verified is quite minimal: Gratian finished the Decretum sometime after 1139 and before 1158, he resided for a time in Bologna, and in addition to legal interests he also held theological ones. Whether he was a layman or a cleric, an academic professor of law or a practicing lawyer, or a young author at the completion of the Decretum or a mature one, will remain unknown absent the discovery of some new source material.

A little more than two years before his death, Thomas Aquinas held his final quodlibetal disputation during Lent in 1272. This event was one of the last official duties Aquinas performed as a master of theology during his second regency at the University of Paris, and by all indications it was a lively affair. It took place during a tumultuous period that led to a general strike at the university, but even if it had been conducted during a relatively normal academic period it would still have been an event not to be missed. Quodlibetal disputations were generally interesting, since they were unscripted debates open to the public, overseen by a master of a discipline, with topics for discussion not decided beforehand. Questions concerning anything (de quolibet) could be brought forward by anyone (a quolibet) in attendance. The oral debate would be refined and sometimes put to writing, and the edited version served as the official record of the event. Given the quodlibetal format, the questions were unpredictable and often covered an exceedingly wide range of topics. One historian of the quodlibetal genre has remarked that anyone who was willing to hold a quodlibetal disputation must have had “a presence of mind quite out of the common, and a competency almost universal in scope,” and “many a master refused to risk himself at it.” In the words of a thirteenth-century Dominican witness to such events, quodlibetal disputations were “on anything at anyone's will (de quolibet ad voluntatem cuiuslibet)”.

My purpose in this book is to give a broad overview of some of the central aspects of and developments in the trinitarian theology written in the Latin West between roughly 1250 and 1350 AD. The emphasis here will be on philosophical theology, on the rational investigation of the Trinity by later-medieval theologians using the full range of tools available to them from especially the Aristotelian tradition of philosophical analysis. Nevertheless, the philosophical nature of the discussion as it is presented here should not obscure the fact that the intense interest with which later-medieval theologians approached the issue is an indication primarily of the immense religious importance it had for them. For the doctrine of the Trinity is at the heart of the Christian faith. On the basis of statements from especially the New Testament that suggested that the savior, Jesus Christ, is the very same God as the Father who sent him and yet is in some way distinct from the Father, the doctrine of the Trinity was formulated by the early Church Fathers and in the Creeds issuing from the ecumenical councils of the second to the fourth centuries AD. According to this doctrine, the Father, the Son, and the Holy Spirit are distinct and yet identical: distinct as persons, identical as God.

FIDEISM, PRAEPOSITINIANISM, AND THE DEBATE OVER PERSONAL CONSTITUTION

In the previous chapter I began to discuss a trend in fourteenth-century trinitarian theology that I labeled “The Search for Simplicity.” I argued there that an overwhelming emphasis on divine simplicity led William Ockham to appeal to the faith as the sole reason for holding a strong use of the psychological model, using the phrase sola fide (“on faith alone”) on several occasions. I called Ockham's use of the psychological model “the psychological model lite” because Ockham said that the Son is literally a Word emanated intellectually, while also basically admitting that he did not know why or how this was the case, since there is no distinct intellect in God. We believe in the strong use of the psychological model – it is held sola fide, its truth assured by revelation and the Catholic Church – and we believe that the Son is a Word having something to do with intellectual emanation; but we can neither explain it nor use reason to support it by making it more plausible or even comprehensible. For Ockham, when it comes to the strong use of the psychological model of the Trinity, reason is fundamentally impotent.

This insistence upon the fundamental impotence of human reason in the face of various theological truths has in fact been seen as a defining characteristic of fourteenth-century thought as a whole.