[Domuni Press] Interview with Yoann Heye: “Prudence Teaches Us to Learn from Our Mistakes”

20 october 2026

Why devote an entire book to prudence?

In Agir avec justesse (Acting with Discernment), Yoann Heye revisits a virtue he considers essential to understanding our choices and our way of life. In this interview, he recounts his intellectual journey from Aristotle to St Thomas Aquinas and explains why experience, education, desire and love occupy a central place in his reflection.

What personally led you to study prudence?

What interested me was the gap between the rather limited understanding of prudence we have today and the considerable importance it holds in the thought of Aristotle and St Thomas Aquinas. We readily associate it with caution: to be prudent would mean avoiding risks. Yet I was discovering a much more dynamic virtue. Prudence comes into play when it is time to act. It requires us to examine reality, deliberate and ultimately make a decision. This seems to me a deeply human question: what should I do when I want to act well, but no one can give me a ready-made answer?

The title, Agir avec justesse, places particular emphasis on action. Why did you choose it?

Because prudence is not merely a matter of thinking correctly. It must lead to action. One may deliberate at length, consider every possibility and never make a decision. That is not yet prudence. The expression “acting with discernment” also conveys the idea of adjustment. No concrete situation is ever exactly like another. We must take into account the people involved, the circumstances, what we know and also what we do not know. Prudence seeks the right course of action without relying on a formula that can be applied automatically.

In your study of Aristotle and St Thomas Aquinas, what interested you most about the differences between them?

I paid particular attention to the place of the will. St Thomas knows Aristotle’s thought in depth, but he does not simply repeat it. His understanding of the faculties of the soul enables him, in particular, to conceive differently of the relationships between intellect, will and appetites.

This changes our understanding of prudence. We do not make decisions through reason that is entirely independent of what we desire or love. Our will plays a part. What we are deeply inclined towards influences the way we deliberate and choose.

You even go so far as to speak of love. This may come as a surprise in a study of prudence…

And yet, this is an essential point in St Thomas’s thought. The will is an appetitive faculty: what we love above other things sets our reflection and our choices in motion.

This also helps us understand why someone who is highly intelligent is not necessarily prudent. They may reason perfectly well and use their intelligence in pursuit of a bad end. Prudence presupposes a rightly ordered will. The quality of our decisions therefore also depends on the deeper orientation of our desires and our love.

Your book also places considerable emphasis on experience. Why?

Because we never act in the abstract. We act with a particular person, at a particular moment and under particular circumstances. Yet no general line of reasoning can enable us to know all these specific details perfectly.

Experience is precisely what teaches us to perceive reality more clearly. A prudent person knows how to learn from what they have already experienced, including their mistakes. I find this aspect particularly important: prudence does not require us never to be mistaken. It also requires us to learn from what has not worked.

Does this mean that prudential judgement is always fallible?

Yes. We may make a decision that seems right to us and later discover that we had overlooked something. In the book, I give the example of someone going through a difficult time whom we wish to comfort by speaking to them about God as a father. Our intention may be good, but such words may prove inappropriate if that person was mistreated by their own father and we are unaware of it.

This example shows how much prudence requires attentiveness and humility. We must seek to adapt our response to the truth of the situation without imagining that we have complete mastery of it.

Can prudence, then, be learned, or is it primarily a matter of accumulating experience?

Experience is indispensable, but it is not enough. Education also plays an essential role. We gradually learn to govern our desires, moderate our reactions, listen, deliberate and judge. I also emphasise the distinction between habit and habitus. A habit can become mechanical: faced with a particular situation, I automatically repeat a particular behaviour. By contrast, habitus enables us to face a new situation with acquired dispositions while still exercising our judgement. Prudence therefore does not produce automatic responses; it forms a person capable of adapting intelligently to reality.

Does this reflection change the way we understand the success of an action?

Yes, because success does not simply mean achieving the desired result. An action may be technically effective while remaining morally wrong.

For both Aristotle and St Thomas, the question also concerns the person who acts. Through my choices, I do not merely transform the external world: I transform myself as well. My actions gradually shape the person I become. This is perhaps what I would most like readers to take away: prudence does not simply teach us to make better decisions. It reminds us that every decision we make contributes to the shaping of our lives. To act well is also to learn, little by little, how to become a better person.

This book is available in French: Agir avec justesse.

Discover and purchase the book in digital format or paperback.