[Domuni Press] Acting Rightly: Prudence from Aristotle to Thomas Aquinas

16 october 2026

How can we make the right decision when circumstances offer us no ready-made answer? In Acting Rightly, Yoann Heye revisits the concept of prudence through the thought of Aristotle and Saint Thomas Aquinas. Far from being a mere attitude of caution, prudence emerges as an essential virtue: the one that enables us to discern, choose and act rightly.

A Forgotten Virtue to Rediscover

In everyday language, being prudent often means avoiding danger, minimising risks or refraining from acting too hastily. Prudence is then associated with reserve, or even a certain timidity. Yet this understanding is far removed from the meaning attributed to prudence by the great philosophical traditions.

In Acting Rightly: Prudence from Aristotle to Saint Thomas Aquinas, Yoann Heye seeks to restore the full depth of this virtue. For both Aristotle and Saint Thomas Aquinas, prudence does not consist in protecting oneself from action; on the contrary, it enables us to act, and above all, to act well.

The question is profoundly practical. We may know general principles, wish to do good and pursue an end that we consider just. But what should we do here and now, in a particular situation? Between intention and action lies a space for discernment. It is precisely here that prudence comes into play.

Aristotle: Learning to Deliberate Well

Yoann Heye begins by returning to the Aristotelian concept of phronesis. For Aristotle, the prudent person is capable of deliberating correctly about what contributes to a good life. Prudence belongs to practical reason: it does not seek merely to know what is true, but to determine what ought to be done.

This distinction is essential. In moral life, it is not enough to apply a rule mechanically. Every situation involves particular circumstances that must be taken into account. Prudence therefore requires experience, the ability to deliberate, sound judgement and a sufficiently nuanced understanding of reality to choose the appropriate means.

Nor can prudence be separated from the other virtues. Making good choices presupposes that desire itself is oriented towards the good. Prudence thus stands at the intersection of intelligence and action: it illuminates choice and gives it its proper measure.

From Phronesis to Prudentia

Saint Thomas Aquinas draws extensively on this Aristotelian legacy, but Yoann Heye shows that he does not merely reproduce it. Aquinas's conception of prudentia is situated within a different understanding of the human person, human faculties and humanity's ultimate end.

In Aquinas's thought, the will acquires a particularly decisive role. Prudence indeed belongs to practical intelligence, but its exercise presupposes a properly oriented will. It is therefore not enough to know how to reason skilfully in order to be prudent.

This distinction helps explain why prudence must not be confused with cunning or efficiency. A person may intelligently choose the best means of achieving an evil objective: such skill does not yet constitute prudence. Prudence presupposes an orientation towards the good and forms part of a virtuous life.

Aquinas also introduces the notion of synderesis, the disposition through which human reason apprehends the first principles of moral action. These principles provide a universal orientation; prudence must then discern how they apply in a concrete situation, which is always particular.

Finding the Right Means in a Changing World

One of the book's major contributions is to show that prudence lies precisely at the point where principles meet a reality that is constantly changing.

How can we do justice to a particular person in particular circumstances? How should we choose between several possibilities that all seem legitimate? How can we determine the appropriate means of achieving a good end? There is not necessarily an automatic answer.

Prudence therefore requires us to examine the situation as it is, take people and circumstances into account, deliberate and then decide. It seeks the concrete mean appropriate to virtuous action.

This also explains why experience is so important. The prudent person learns from reality, including from mistakes. Judgement develops gradually. Prudence is therefore neither a technique nor a catalogue of solutions: it is an acquired disposition that enables us to judge and act more effectively.

Prudence at the Heart of the Virtues

Yoann Heye's study also brings to light the particular place prudence occupies among the virtues. It maintains close relationships with justice, fortitude and temperance. In Saint Thomas Aquinas's thought, this interconnection becomes particularly clear: the moral virtues need prudence, while prudence itself presupposes sound moral dispositions.

This interdependence gives rise to a genuine process of personal formation. Acting justly does not consist merely in performing a good deed on a particular occasion. Through their decisions and actions, human beings transform themselves.

Prudence thus becomes a virtue of self-governance. It brings together knowledge, will, desire, experience and action in order progressively to direct one's life towards its ultimate end: happiness in Aristotle's thought, and Beatitude in the perspective of Saint Thomas Aquinas.

A Philosophy for Learning to Act

By bringing Aristotle and Saint Thomas Aquinas into dialogue, Acting Rightly offers more than a historical study of two philosophical doctrines. The book brings to the fore a question that remains profoundly relevant today: how can we make sound decisions in complex situations?

Between rules that are too general to address every case and decisions left entirely to individual feelings, prudence opens up another path. It invites us to cultivate our judgement, gain experience, order our desires and test our choices against reality.

Ultimately, rediscovering prudence means recovering a demanding conception of freedom: not simply the ability to choose, but learning to choose what enables us to act well — and, through our actions, to become better people.

This book is available in French: Acting Rightly — Domuni Press.

Discover and purchase the book in digital edition or paperback edition.