Aquinas on the Relationship of Philosophy and Theology

Pope Benedict XVI’s weekly catechesis.

During his general audience on June 16, Pope Benedict XVI continued his catechesis on the Christian culture of the Middle Ages, specifically focusing on the works of St. Thomas Aquinas.

The Holy Father pointed out that St. Thomas Aquinas firmly believed in the harmony of faith and reason and respected the autonomy and complementarity of these two ways of knowing the truth that has its ultimate origin in God’s word. This complementary relationship between the two is a reflection of the truth that God’s grace builds on as it elevates and perfects human nature and enables man to pursue his deepest desire for happiness.

Dear brothers and sisters,

Today, I would like to continue my presentation on St. Thomas Aquinas, a theologian of such importance that the Second Vatican Council explicitly recommended the study of his works in two documents, the decree Optatam Totius (on the formation of priests) and the declaration Gravissimum Educationis (on Christian education).

This goes back as far as 1880, when Pope Leo XIII, who esteemed him highly and was a great promoter of Thomism, declared St. Thomas Aquinas the patron saint of Catholic schools and universities.

Plato and Aristotle

The principal reason why he is so highly valued rests not just in the content of his teaching, but also in the method he adopted, especially the entirely new way he treated philosophy and theology, bringing into focus both their harmony and their differences.

The Fathers of the Church had to deal with various Platonic philosophies that presented a complete worldview and explanation of human life, including the question of God and religion. In their response to these philosophies, they themselves worked out a complete vision of reality, with faith as their starting point and using elements of Plato’s philosophy in order to respond to man’s most basic questions.

They called this worldview, which was based on biblical revelation and which they developed using Platonism corrected in light of faith, “our philosophy.” The word “philosophy,” therefore, did not refer to a purely rational system and, as such, distinct from faith, but rather indicated an overarching vision of reality that was constructed in the light of faith and thought through by human reason, which made it its own.

Of course, it was a worldview that went beyond the specific capabilities of reason, but, even so, reason could take pleasure in it.

However, St. Thomas’ encounter with the pre-Christian philosophy of Aristotle (who died around 322 B.C.) opened up new horizons. Aristotelian philosophy was obviously a philosophy that was worked out without any knowledge of the Old and New Testaments, an explanation of the world without using revelation and based on reason alone. This purely rational framework was very convincing.

As a result, the Church Fathers’ old format of “our philosophy” no longer worked. The relationship between philosophy and theology, between faith and reason, had to be re-thought. There is a “philosophy” that is complete and convincing in and of itself, a rationality that precedes faith, and then there is a “theology,” which is a way of thinking through faith and in faith.

Faith and Reason

The burning question was as follows: Are the world of rationality — a philosophy developed without Christ — and the world of faith compatible? Or are they mutually exclusive?

Many people held that the two worlds were incompatible, but St. Thomas was firmly convinced that they were indeed compatible and even that the philosophy that had been elaborated without knowledge of Christ was practically awaiting Jesus’ light in order to be complete. This was St. Thomas’ big “surprise,” which was decisive in the development of his thought.

This great teacher’s lifelong mission was to demonstrate the independence of philosophy and theology and, at the same time, their interdependent relationship.

Thus, we can understand why, back in the 19th century when people were loudly affirming the incompatibility between modern reason and faith, Pope Leo XIII pointed to St. Thomas as a guide in the dialogue between the two.

In St. Thomas’ theological works, he started from this relationship and worked out its specifics. Faith consolidates, integrates and illuminates the heritage of truth that human reason can acquire. The trust St. Thomas placed in both ways to knowledge — faith and reason — can be traced to his conviction that both come from the single wellspring of all truth, the divine Logos, which is at work in the area of both creation and redemption.

However, in acknowledging this harmony between reason and faith, we also need to recognize that they make use of different cognitive procedures. Reason accepts a truth on the strength of its intrinsic evidence, indirect or immediate; faith, on the other hand, accepts a truth based on the authority of the Word of God that has been revealed to us.

At the beginning of his Summa Theologiae, St. Thomas writes: “We must bear in mind that there are two kinds of sciences. There are some which proceed from a principle known by the natural light of intelligence, such as arithmetic and geometry and the like. Others proceed from principles known by the light of a higher form of knowledge: Thus the science of perspective proceeds from principles established by geometry, and music from principles established by arithmetic. So it is that sacred doctrine is a science because it proceeds from principles established by the light of a higher form of knowledge, namely that of God and the blessed” (I, q. 1, a. 2).

A Mutual Relationship

This distinction ensures the autonomy both of human sciences and theological study. However, this is not tantamount to some kind of separation.

Rather, it implies mutual and advantageous collaboration. Faith, in fact, protects reason from any temptation to mistrust its own capacity.

It stimulates it to open up to even broader horizons. It keeps alive the quest for that which is fundamental and, when reason itself is applied to the supernatural sphere of the relationship between God and man, it enriches its own work.

According to St. Thomas, for example, human reason can undoubtedly attain to the affirmation of the existence of one God, but only faith, which accepts divine revelation, is able to attain to the mystery of the love of the triune God.

On the other hand, it is not only faith that helps reason. Reason, too, with the means at its disposal, can do something important for faith, offering it a threefold service that St. Thomas summarizes in the preface of his commentary on Boethius’ De Trinitate: “Demonstrating the foundations of the faith; using metaphors to explain the truths of faith; refuting objections that are raised against faith” (q. 2, a. 2).

The entire history of theology is fundamentally the exercise of this task of the intellect, which shows the intelligibility of faith, its inner structure and harmony, its reasonableness and its ability to promote what is best for man.

The correctness of theological reasoning and its true cognitive significance is based on the value of theological language, which, according to St. Thomas, is primarily analogical. The distance between God the creator and his creatures is infinite; the dissimilarities are always greater than the similarities (see Denzinger-Schönmetzer 806). Nevertheless, despite all the difference between the Creator and his creatures, there is an analogy between created being and the being of the Creator, which allows us to speak with human words about God.

The Role of Revelation

St. Thomas based his teaching on analogy not only on purely philosophical arguments, but also on the fact that God himself has spoken to us through revelation and has, therefore, authorized us to speak about him. I feel it is important to reiterate this teaching. In fact, it helps us to overcome certain objections raised by modern atheism, which denies that religious language possesses objective meaning and maintains instead that its value is only subjective or merely emotional.

This objection arises from the fact that positivist thought is convinced that man does not know “being” itself, but only the functions of reality that can be experienced. Along with St. Thomas and the great philosophical tradition, we have the conviction that man truly knows not only its functions — the object of the natural sciences — but something of being itself. For example, he knows the person, the “you” of the other person, and not only the physical or biological aspect of his being.

In light of this teaching of St. Thomas, theology affirms that, because we are in contact with being, religious language does have meaning — however limited it may be — like an arrow flying towards the reality it signifies. This fundamental harmony between human reason and Christian faith is seen in another basic principle of Aquinas’ thinking: Divine grace does not nullify but takes up and perfects human nature.

Indeed, human nature, even after sin, is not completely corrupt, but wounded and weakened. Grace, which God lavishes and communicates through the mystery of the Word made flesh, is an absolutely gratuitous gift by which nature is healed, strengthened and aided in its pursuit of happiness, the innate desire in the heart of every man and woman.

All the faculties of the human being are purified, transformed and elevated by divine grace.

Nature and Grace

An important application of this relationship between nature and grace can be perceived in St. Thomas Aquinas’ moral theology, which is extremely relevant today.

At the center of his teaching, he puts the new law, which is the law of the Holy Spirit. With a profoundly Gospel-oriented focus, he insists on the fact that this law is the grace of the Holy Spirit given to all those who believe in Christ. To this grace is joined the written and oral teaching of doctrinal and moral truths, handed down by the Church.

Stressing the fundamental role of the work of the Holy Spirit in moral life — the work of grace — from which the theological and moral virtues flow, St. Thomas helps us to understand that all Christians can attain the high ideals of the Sermon on the Mount if they live in a genuine relationship of faith in Christ, if they are open to the work of his Holy Spirit.

However, Aquinas adds, “even if grace is more effective than nature, nonetheless nature is more essential for man” (Summa Theologiae, Ia, q, 29, a. 3), for whom, from the viewpoint of Christian morality, there is a place for reason, which is capable of discerning natural moral law.

Reason can recognize this law and consider what is good to do and what is good to avoid in order to obtain the happiness that every heart desires, but that also implies a responsibility towards others and, therefore, a quest for the common good.

In other words, man’s theological and moral virtues are rooted in human nature. Divine grace accompanies, supports and is the impulse behind the commitment to moral living, but, according to St. Thomas, all men and women, believers and nonbelievers, are called to recognize the demands of human nature as expressed in natural law and to draw inspiration from it when formulating positive law, that is, the laws which civil and political authorities produce to regulate society.

When the natural law and the responsibility it implies are rejected, the way is dramatically thrown open to ethical relativism at the individual level and to totalitarianism at the political level. Defending the universal rights of man and affirming the absolute value of the dignity of the person presupposes some foundation. Is not this foundation natural law and its non-negotiable values?

In his encyclical Evangelium Vitae, Venerable John Paul II wrote the following words that remain relevant today: “It is therefore urgently necessary, for the future of society and the development of a sound democracy, to rediscover those essential and innate human and moral values which flow from the very truth of the human being and express and safeguard the dignity of the person: values which no individual, no majority and no state can ever create, modify or destroy, but must only acknowledge, respect and promote” (No. 71).

A Word for Us Today

In conclusion, St. Thomas presents us with a concept of human reason seen as broad and trustworthy. It is broad because it is not limited to the realm of so-called empirical-scientific reason; it is open to all of existence and, therefore, also to the fundamental and inescapable questions of human life.

It is trustworthy because human reason, especially if it accepts the inspiration of Christian faith, promotes a civilization that recognizes the dignity of the person, the inviolability of his rights and the cogency of his duties.

It is not surprising that the doctrine regarding the dignity of the person, fundamental for the recognition of the inviolability of man’s rights, matured in schools of thought that took up the legacy of St. Thomas Aquinas, who had a very high concept of the human creature. He defined it, in his rigorously philosophical language, as “that which is found to be most perfect in all of nature, that is, a subject that subsists in a rational nature” (Summa Theologiae, Ia, q. 29, a. 3).

Let us never forget that the depth of St. Thomas Aquinas’ thought flows forth from his lively faith and his fervent devotion, which he expressed in inspired prayers, such as this one in which he beseeches God in the following words: “Grant me, I pray, the will to seek you, the wisdom to find you, the life that pleases you, a perseverance that waits for you with trust, and a trust that will, in the end, lead to possessing you.”

Register translation