I was pleased to learn that the Pontifical Academy of Social Sciences has chosen to celebrate the 750^th anniversary of the death of Saint Thomas Aquinas by sponsoring a Workshop on the theme, “Aquinas’ Social Ontology and Natural Law in Perspective. Insights for and from the Social Sciences”. I express my gratitude to all taking part in this significant gathering and I offer my prayerful good wishes for the fruitfulness of your discussions.

To be sure, Saint Thomas did not cultivate the social sciences as we know them today. Yet his rigorous study of the philosophical and theological implications of the biblical datum that the human being is created in “the image of God” (Gen 1:27), which found expression in his varied writings, can be said to have helped prepare the way for the development of these modern sciences. Thomas’ work demonstrates both his commitment to understanding the revealed word of God in all its dimensions and, at the same time, his remarkable openness to every truth accessible to human reason. The Angelic Doctor was profoundly convinced that since God is the truth and the light that illumines all understanding, there can be no ultimate contradiction between revealed truth and the truths discovered by reason. Central to his understanding of the relationship of faith and reason was his conviction of the power of God’s gift of grace to heal human nature weakened by sin and to elevate the mind through participation in God’s own knowledge and love, and thereby to enable us to understand and correctly order our lives as individuals and in society.

Contemporary social sciences approach human affairs and the pursuit of human flourishing through a variety of approaches and methods that should be grounded in the irreducible reality and dignity of the human person. Aquinas was able to draw upon a rich philosophical heritage which he interpreted through the lens of the Gospel in order to affirm that the person, as “the most perfect thing in all nature” (ST I, q. 29, a. 3), is the pillar of the social order. Created in the image and likeness of the triune God, individuals are meant, through personal and interpersonal relationships, to live, grow and develop within communities. For this reason, “it is natural that human beings should live in society with many others in order to procure by the work of their hands and body, enlightened by the light of their intelligence and the strength of their will, the material and spiritual goods for their well-being and good-living, for their happiness” (De regno, B. I. c. 1).

Drawing on principles already established by Aristotle, Thomas thus held that spiritual goods precede material goods and that the common good of society precedes that of individuals, inasmuch as man is by nature a “political animal”. His engagement with the ethical and political works of the great classical thinkers is evident from his commentaries, and is reflected especially in the questions he devoted to justice, notably in his celebrated Treatise on Law (ST I-II, qq. 90-108). While his influence in shaping the moral and legal thinking of modernity is beyond doubt, a recovery of the philosophical and theological perspective that informed his work could prove quite promising for our disciplined reflection on the pressing social issues of our own time.

Aquinas upholds the inherent dignity and unity of the human person, who belongs both to the physical world by virtue of the body and to the spiritual world by virtue of the rational soul. A creature capable of distinguishing between true and false according to the principle of non-contradiction but also of discerning good from evil. This innate capacity for discernment and for ordering or disposing acts to their ultimate end through love, traditionally called “natural law”, is, as the Catechism of the Catholic Church states, quoting Thomas, “nothing other than the light of understanding placed in us by God; through it we know what we must do and what we must avoid. God has given this light or law at the creation” (No. 1955).

Today it is essential to recover an appreciation of this “natural inclination to seek the truth about God and to live in society” (ST I-II, q. 94, a. 2) in order to shape social thought and policies in ways that foster rather than impede the authentic human flourishing of individuals and peoples. For this reason, my Predecessors and I have consistently reaffirmed the relevance of natural law in discussions regarding the ethical and political challenges of our time. In the words of Benedict XVI, the “universal moral law provides a sound basis for all cultural, religious and political dialogue, and it ensures that the multifaceted pluralism of cultural diversity does not detach itself from the common quest for truth, goodness and God” (Caritas in Veritate, 59).

Thomas’ confidence in a natural law written within the human heart can thus offer fresh and valid insights to our globalized world, dominated by legal positivism and casuistry, even as it continues to seek solid foundations for a just and humane social order. Indeed, following Aristotle, Thomas was well aware of the complexity of applying law to concrete actions, and thus emphasized the importance of the virtue of epikeia. In his words, “human actions, with which laws are concerned, are composed of contingent singulars and are innumerable in their diversity… if the law be applied to certain cases it will frustrate the equality of justice and be injurious to the common good, which the law has in view”. Consequently, “the good thing is, leaving aside the letter of the law, to follow what justice and the common good demand” (ST II-II, q. 120, a. 1).

If the Angelic Doctor grounds his understanding of human dignity and the requirements of a “social ontology” in human nature, and thus in the order of creation, as a Christian thinker he also, necessarily, adds that our human nature, wounded by sin, is healed and elevated by grace as the fruit of the redemption accomplished by Christ. At the beginning of his great Christology, the third part of the Summa Theologiae, Thomas affirms, in continuity with the teaching of the Scriptures and the Fathers of the Church, that the Incarnation of the Son of God reveals the supreme dignity of human nature. This conviction was eloquently restated in our own time by the teaching of the Second Vatican Council that “Christ, the new Adam, in the revelation of the mystery of the Father and his love, fully reveals man to himself and brings to light his high calling” (Gaudium et Spes, 22). The fullness of grace present in the humanity of the Redeemer is then communicated to the members of his Body, the Church, to which all mankind is called. As Head of that Body, Christ distributes his grace in various ways to each member, according to his or her unique gifts and vocation.

Thomas’ insights into this outpouring of redemptive grace and the variety of ways in which that grace is communicated for the building up of the Body has rich implications for an understanding of the dynamics of a sound social order grounded in reconciliation, solidarity, justice and mutual concern. In this sense, Benedict XVI could affirm that, precisely as objects of God’s love, men and women become in turn subjects of charity, called to reflect that charity and to weave networks of charity (cf. Caritas in Veritate, 5) in the service of justice and the common good.

It is this greater dynamic of charity received and bestowed that has given rise to the Church’s social teaching (cf. ibid.), which seeks to explore how the social benefits of redemption can become visible and operative in the lives of men and women as social beings whose individuality is ineluctably immersed in a greater history, culture and tradition. Here, Thomas points out, we see the heart of the Christian life as an act of priestly worship aimed at the glorification of God and the sanctification of our world. Within this perspective, the Angelic Doctor resolutely upholds the priority of works of mercy. In his words: “We worship God by external sacrifices and gifts, not for his own profit, but for that of ourselves and our neighbour. For he needs not our sacrifices, but wishes them to be offered to him, in order to arouse our devotion and to profit our neighbour. Hence mercy…is a sacrifice more acceptable to him, as conducing more directly to the well-being of our neighbour” (ST II-II, q. 30, a. 4, ad 1).

Dear friends, in these years of my Pontificate I have sought to privilege the gesture of foot washing, following the example of Jesus who at the Last Supper took off his cloak and washed his disciples’ feet one by one. The washing of feet is undoubtedly an eloquent symbol of the Beatitudes proclaimed by the Lord in the Sermon on the Mount and of their concrete expression in works of mercy. With this gesture, the Lord wanted to leave us “an example so that you may do as I have done” (Jn 13:15). Indeed, as Aquinas teaches, with such an extraordinary action, Christ “showed all the works of mercy” (In Ioan. XIII). Jesus knew that when it comes to inspiring human action, examples are more important than a flood of words.

In these days, as you approach the rich patrimony of religious, ethical and social thought bequeathed to us by Saint Thomas Aquinas, I am confident that you will find inspiration and enlightenment for your own contributions to the various social sciences, in full respect for their proper methods and objectives. I renew my good wishes for your deliberations and I pray that each of you, in your work and in your lives, will find fulfilment in our common commitment to contribute to a future of fraternity, justice and peace for all the members of our human family. Upon each of you, and your loved ones, I cordially invoke the Lord’s abundant blessings.

From the Vatican, 7 March 2024

Francis