Ezra Sullivan, O.P. Habits and Holiness: Ethics, Theology, and Biopsychology. Thomistic Ressourcement Series, vol. 16. Washington, DC: The Catholic University of America Press, 2021. 552 pp., paperback; $34.95.

Cover art: Lorenzo Lotto, Allegory of Virtue and Vice (1505)

During junior year, I recall dozing off in the college library, Aristotle’s Nicomachean Ethics in hand. Not only was I an undergraduate in need of sleep, but Aristotle’s text provided the chance. When required to teach ethics to similarly unprepared college students, I would point out the passage in the Ethics where Aristotle argues that neither was I old enough to teach nor they to learn the material. Students would laugh before realizing my earnestness. Overall, however, my experience has simply reflected Aristotle’s own argument, that only those sufficiently mature can understand or be taught moral philosophy in a formal sense (keeping in mind Aristotle’s caveat in the Ethics about taking refuge in mere words: II.4, 1105b12ff).

Another challenge, among the many, for the reception of Aristotelian or Thomistic virtue ethics is whether or not its underpinning human psychology is still relevant or able to be brought up to meet or exceed the standards of contemporary research. That this is in fact the case, and more, that St. Thomas’s principle can better equip our understanding of habits, is defended in Fr. Ezra Sullivan’s mighty tome, Habits and Holiness: Ethics, Theology, and Biopsychology, a work of stunning breadth and wealth. One can find the introduction and some selections of the book on Academia, and a recent special issue of the American Catholic Philosophical Quarterly whose topic is contemporary Thomistic psychology features a précis of the work, written by Sullivan himself.

Sullivan’s book is one with which further scholarly and even pastoral engagement is needed. Such were the contexts in which I studied the book, while leading a monthly seminar on Habits and Holiness during the 2021–22 academic year. The participants were diocesan priests in Wichita, and, apart from the fraternity of the group itself, the further purpose of the discussion was to become better ministers of the sacrament of confession towards the end of bearing greater spiritual fruit in the lives of penitents. After reviewing the scope and contents of the work, along with a closer look at some points of detail, I close with some feedback from the monthly seminar.

The Formation of Subterranean, Human, and Divine Habits

As Sullivan states in his précis, “We do not start each day ex nihilo, our life a blank slate ready to receive whatever we may scribble  upon it. Rather, our soul is like a parchment palimpsest with old script that has been written in us by nature, experience, and choice: these writings are habits of various sorts, and they affect our thoughts, desires, emotions, and choices even when we are unaware of them” (345). The book’s pupose is to examine the multiple types of human habitus, all present in the writings of the Common Doctor, and all relevant to the practical work of human living. The sources upon which Sullivan draws include not just theology but philosophy, biology, and contemporary psychology, as indicated by the subtitle. The scope of this project, as well outlined in the book’s introduction, is daunting, and the reading of the book is made all the better, even if it is at time an arduous climb, for its success in executing what it sets out to do. Thus, Sullivan not only engages with St. Thomas’s own interpreters in a theological and philosophical register, but he also enters into dialogue and debate with contemporary psychological analyses of virtues and vices, emotions, and dispositions.

The book’s overall structure is articulated by seven principal senses of habitus drawn from the works of Aquinas. On the side of natural habits, those arising from being or nature are either general (habit as a stable disposition derived from one’s general nature), or specific to an individual (habit as as a stable disposition from one’s individual nature). Natural habits arising from some change or activity are either nonvolitional or volitional (the latter including virtues and vices). On the side of supernatural habits, these likewise are divided into the entitative habit of grace or operative habits with which we can cooperate volitionally (non-acquired, supernatural, voluntary dispositions, or the infused and theological virtues), or which God alone works in us (non-acquired, supernatural, nonvolitional dispositions, the Gifts of the Holy Spirit). The book’s first eight chapters walk through these in great detail, the treatment falling broadly into two parts: “subterranean” habits prior to volition and those engaging volition in some way (whether “human” or “divine”). The book concludes with a practical third part on habit development and formation.

The sheer quantity of information presented is at times overwhelming—indeed, the volume would be two books were it not that the theological and philosophical were not so well synthesized with the contemporary psychological and physiological data. Following along is aided by many figures or tables. The aforementioned seminar made frequent use of these since they crystalize the exposition in various chapters. It seems to me that the principal strength of the exposition is how it follows the order of learning from the more familiar habits closer to sense experience and ending with the theological habits and gifts. This permits one, whether only reading the book or also discussing it, to slowly and iteratively develop a grasp of the analogical range of habitus not only in Aquinas’s work but also in the reality of things.

The Habit Loops

One point of detail that I would like to highlight in particular—and which was also a point to which the discussion group returned—is Sullivan’s use of the idea of a “habit loop”. Introduced in the fourth chapter—and thus relying upon the prior discussions of physiological and non-volitional psychological dispositions that well or ill-diposed character formation—the habit loop involves the idea of “behavioral momentum”. Sullivan compares the intertia or “momentum” or a behavior analogate in human nature: just as a body resists changes, so too our behavior has its own “inertia” (although momentum is better, in my view, as an analog). Behavioral momentum gives rise to predictability of behavior, an instinctive aspect of behavior, and underlies its teleology. “With our character mass, we have preferential inclination to ward what we perceive as good for us in the moment, and resistance to what is opposed to that good.” (162)

In the dynamics of human life, behavioral momentum is not linear but cyclic, due to human needs, memory, and patterns of life: “Here we encounter … the habit loop, which is composed of three parts: a cue/trigger/stimulus/antecedent, a routine/behavior, and a reward/positive consequence. ... A cue is a trigger that initiates the habit. ... A routine is a stereotyped form of behavior that is the chief manifestation of the habit. ... Finally, a reward is the effect of the habit … a good that causes some kind of fruition.” (163) Thus, the A-B-C of antecedents, behavior, and consequences give the loop its structure. However, instead of leaving the loop in what might appear to be a Humean analysis of custom, Sullivan introduces more familiar Thomistic principles of the object and end of voluntary actions, giving a more holistic picture of the elements of human character.

Thus, the habit loop must be completed by adding its overarching end. The loop is stable, but it is not closed:  “Because habits are the imprint of previous acts, habits by their nature share in the teleology of the acts from which they were made.” (170) The “loop” or “cycle” analogy must be understood historically (not as mere repetition); the loop is cyclic, psycho-physical process of a rational agent (thus, there are clear limits of the “momentum” analogy). A habit is thus a teleologically-modifiable feedback loop, open to intervention, perfection, and defection. In developing and extending this analysis, Sullivan is able to navigate between a mechanistic reductionism of habits and an angelic transcending of the human need for them; we possess freedom within and not without or despite our virtuous habituation: “Deliberate choice is … the ‘heart’ of a voluntary act as well as a fully human habit. ... When a movement possesses the core of intentionality, that is, when an agent chooses an object and directs it toward an end, the movement is no mere movement: it constitutes a human act, even when the movement is part of a habit loop.” (174, 175) We can develop “persistent intentionality” that is a perfection and not a hindrance to a virtuous life, a chosen automaticity: “The results of expertly harnessing certain kinds of automaticity is that the power of one’s original intention ingraining the habit retains its force, and even grows stronger through subsequent affirmations and actions. ... Once again, we find that fully voluntary habits form a self-reinforcing spiral. … Only by harmoniously uniting the panoply of habits can a human being come to act in a fully human mode.” (196)

Sullivan does not avoid the practical even in the more speculative or analytic parts of the book. In this instance, he notes three practical consequences of the reality of the habit loop (164–65): they permit predictability of behavior, the identifiability of habits, and the possibility of the alterability of habits. The first is because habits have a momentum due to their causes: human character and triggers (interior and exterior antecedents); the second because the habit loop allows us to “identify signs that a person possesses a habit” (165); the third because “There are particular techniques that a person can employ in order to help his knowledge and desire be realized” (165) given that the “loop” in question has been identified.

When Will I Use This in Real Life?

The practical was in the forefront of the seminar discussion which I led on this book. While the intelligible density of the text made it a challenge, for each chapter one can find examples, scenarios, or practical questions whose resolution requires that the discussion turn to the speculative principles laid out in the text. Personal experience and pastoral necessity can then find root in contemplative insight. That was at least the experience of the group (in the better moments). One participant writes: “The book helped me to think more rationally about human action, especially in the way that we express freedom through what we say and do. Before reading, habits felt to me something like accidental qualities of my person. Now, I see them as more deeply rooted in my nature, that my human action and specifically my habits express something of who I am and who I can become. The book revealed to me a science of habit formation that gives me both personal and pastoral confidence in virtue growth. That being said, reading it is a bit of a slog through the muck, and made it difficult for me to access the core of his ideas. Although I appreciate his attempt at robust discussion of the underlying rationale, he took too many detours to get to the payoff that came with the last few chapters.”

I would note, however, that Sullivan has a much more approachable volume for a broader audience (only available after we had started our group!), and which one of the participants bought and read alongside Habits and Holiness as we were finishing it. That book is Heroic Habits: Discovering the Soul’s Potential for Greatness.

Conclusion: The Perennial Need for Heroic Habits

Overall, Fr. Ezra Sullivan’s Habits and Holiness is a powerful work, deeply versed in the moral theology of habit formation, and well worth one’s time. It is the sort of book that would teach me how to teach an ethics course better (when I next have the chance). And, unlike my first experiences reading the Ethics, it had not a soporific but rather a more sapiential effect.