The Spirit of Aeterni Patris in the Person of Leo XIV

The election of the new Pope, Leo XIV, has been received with joy and hope throughout the Church. The world watches expectantly as this pontificate begins—one that, from his very first words, has expressed a desire to guide the Church by the hand of God while simultaneously seeking to build bridges of dialogue, the latter with a strong sense of social justice. Thus, in the midst of contemporary challenges, Leo XIV has chosen to look to the past—not out of nostalgia, but to give continuity to the values that have been upheld in similar situations. And he has done so, starting with his name.

A Name with History: From Leo XIII to Leo XIV

Leo XIV did not choose his name at random. In a brief but significant meeting, he explained to the cardinals that he did so in honor of the last pontiff who bore it: Leo XIII, author of the renowned social encyclical Rerum Novarum (1891). However, it’s worth remembering that before this foundational text of the Church’s Social Doctrine, Leo XIII wrote Aeterni Patris (1879), an encyclical in which he called the entire Church—and particularly Catholic academic institutions—to restore philosophy according to the spirit of Saint Thomas Aquinas.

For most of us, who to some extent are not familiar with the context in which this encyclical was promulgated, a question arises: why did Leo XIII feel compelled to write Aeterni Patris? To answer that, it might be helpful to consider the following analogy: faced with an illness, a good doctor knows that he cannot help his patient without first identifying what is causing the symptoms. However, diagnosis alone will not solve the problem, for any effective treatment requires administering the proper cure.

Leo XIII clearly understood that the crisis of modernity was not only moral or political, but fundamentally philosophical, and that once the cause behind the symptoms was identified, an ad hoc treatment was required. Continuing the medical analogy, one might think that the most appropriate solution would be to remove the foreign body—like in the case of a tumor, for example—that impedes the proper functioning of the body. However, that was not the path Leo XIII followed. He did not propose confrontation or rejection—extirpation—but rather dialogue and integration, proclaiming that the perennial wisdom of the Thomistic tradition should be recovered and placed in fruitful dialogue with modern thought.

After all, although the latter had caused much harm, this did not invalidate its true discoveries. Far from arguing that they should be discarded, Leo XIII recognized the need to correct the deviations and excesses of contemporary thought by providing a new foundation: a tradition—the Thomistic one—that would offer a coherent framework to order and understand the scope of modern advances. Hence the famous phrase of Leo XIII: Vetera novis augere et perficere (“To strengthen and complete the old by the aid of the new.”)

As attested by the more than 180 books on Thomas Aquinas published by Cambridge University Press and Oxford University Press—including, notably, a Companion to Aquinas, now in its seventh edition, and a nearly 600-page Handbook of Aquinas—this tradition is highly esteemed today among some of the most prestigious secular universities. We must then ask ourselves: how much more should we Christians be committed to studying Thomas Aquinas?

The Election of Leo XIV: A Sign for Catholic Psychology

Among all sectors that should feel interpellated by the new Pope’s name, one stands out in particular: that of Catholic psychologists. If any discipline has suffered acutely from the divorce between faith and reason, between empirical science and the philosophy of being, it is psychology. For although it was born from the aspiration to understand the human being, modern psychology has, for nearly a century and a half, followed a path marked by reductionism and fragmentation.

In the name of scientific rigor, it abandoned the question of the soul. In the name of empirical precision, it avoided dialogue with philosophy. And in the name of neutrality, it uprooted its knowledge of the person from any ethical or teleological framework. The result is a psychology that often knows much about processes but little about purposes; that studies behavior but barely touches the mystery of freedom; that seeks efficiency, but sometimes forgets dignity.

In this context, the gesture of the new Pope should not be perceived as a purely ecclesial matter, but as a sign for Catholic psychologists, universities, clinical training centers that claim to be heirs to an integral vision of the human being. In other words, it should be a reminder that without a solid philosophical anthropology, psychology remains incomplete, and that without a philosophy that recognizes man as a unity of body and soul, endowed with reason and will, every therapeutic effort runs the risk of mutilating what is most essential to the person, thereby becoming iatrogenic

Restoring Thomas, Dialoguing with Science

The central point of Aeterni Patris was not merely to promote Thomism as just one school among others, nor to turn it into a closed or rigid doctrine. What Leo XIII sought was to restore a philosophical spirit capable of sustaining dialogue between faith and reason, theology and empirical sciences. In this sense—whether due to his notion of truth as the conformity of the intellect to reality, or his conviction that all truth, wherever it may come from, reflects Divine Truth—Saint Thomas stands out as an exemplary master, capable of offering openness without sacrificing depth. In contrast, other positions do not achieve the same. Quite the opposite.

As might be expected, embracing schools of thought that ignore fundamental truths about human nature has direct consequences for psychology. For only a psychology that starts from a true notion of the human being—as a rational being, free and ordered toward a transcendent end (God)—can truly help people understand themselves and heal. And only a psychology that manages to integrate the discoveries of neuroscience, clinical work, and empirical observation with a philosophy of the soul, an ethics of the good, and a metaphysics of being will be worthy of the concrete human person.

For this reason, when today’s human sciences tend to lose sight of the subject in favor of data, the name of Leo XIV should invite us to consider that returning to Thomas is not a backward step, but the way to move forward without losing sight of what is essential—and that, therefore, true innovation does not consist in abandoning the past, but in founding new developments on the perennial principles of reality.

A Challenge for Our Institutions

This new pontificate represents a providential opportunity for universities, psychology faculties, publishing houses, professional associations, and faith-inspired therapeutic centers to reexamine their foundations. We must ask ourselves if we are training psychologists capable of building bridges between the truths revealed by theology and those discovered in the laboratory. Are we offering our students a vision of the human person that acknowledges their transcendent vocation? Have we perhaps uncritically accepted the anthropological models dominant in academic circles? These may contain partial truths—which is why they are somewhat credible—but let us not forget that only the whole truth, as the apostle John says (Jn 8:32), will set us free.

That's why the figure of Leo XIV should drive us, as the Church, not to settle for merely adapting psychology to Christianity, but to transform it from its roots, so that it does justice to the full reality of the human person. This means recovering Thomas not as a mere reference, but as a master of thought. It means fostering dialogue with the sciences without falling into scientism. And, above all, it means forming psychologists who understand their work as a participation of God’s action, Who heals the brokenhearted and binds up wounds (Ps 147:3).

Toward a Psychology with a Soul

In a world steeped in pragmatism, fractured in its foundations, and riddled with contradictions, the name chosen by the new Pope should reminds us that only an integral vision of man can bring true healing and peace. In other words, his decision is the perfect occasion to evoke in our memory the call of his predecessor: to restore the perennial philosophy to illuminate the human sciences—and among them, psychology in particular.

For Catholic psychologists, this reminder is both a challenge and a promise. A challenge, because it entails revising methods, content, and horizons. But also a promise: that a truly human, deeply Christian, and rigorously scientific psychology is possible. A psychology that does not abandon the soul—because without it, the human person disappears from our sight.

Nicolás Eyzaguirre Bäuerle

Editor-in-chief