by Pope John Paul II
The encyclical is based on a fundamental principle which lends it a profound inner organic unity: it is the principle
of harmony between the truths of reason and those of faith. It is this that was uppermost in the heart of Leo XIII. This principle, always consequential and relevant, has made considerable progress in the last hundred
years. Suffice it to consider the consistent Magisterium of the Church from Pope Leo XIII to Paul VI and what was completed in Vatican Council II, especially in the documents Optatam totius, Gravissimum
educationis and Gaudium et spes.
In light of Vatican Council II, we see, perhaps better than a century ago, the unity and authentic Christianity, between reason and faith, thanks to the directives of
Aeterni Patris of Leo XIII, who with this document, subtitled De philosophia christiana...ad mentem Sancti Thomae...in scholis catholicis instauranda,
showed awareness that a crisis, a rupture, a conflict, or least an obscuration in the relationship between reason and faith had occurred.
Within the culture of the 19th century two extreme attitudes in
fact can be singled out: rationalism (reason without faith) and fideism (faith without reason). Christian culture moves between these two extremes, swinging from one part or the other. Vatican Council I had already had
its say on the matter. It was then time to mark out a new course in the internal studies of the Church. Leo XIII farsightedly prepared for this task, presenting again—in the sense of establishing—the perennial thought
of the Church in the clear, deep methodology of the Angelic Doctor.
The dualism setting the reason and faith in opposition, not at all modern, constituted a renewal of the medieval doctrine of the "double
truth," which threatened from within "the intimate unity of the man-Christian" (cf. Paul VI, Lumen ecclesiae,
no. 12). It was the great scholastic doctors of the 13th century that put Christian culture on the right road again. As Paul VI stated, "in accomplishing the work signaling the culmination of the medieval Christian thought, St. Thomas was not alone. Before and after him many other illustrious doctors worked toward the same goal: among whom St. Bonaventure and St. Albert the Great, Alexander of Hales and Duns of Scotus are to be recalled. But without a doubt St. Thomas, as willed by divine Providence, reached the height of all 'scholastic' theology and philosophy, as it is usually called, and set the central pivot in the Church around which, at that time and since, Christian thought could be developed with sure progress" (
Lumen ecclesiae, no. 13).
It is for this reason that the Church has given preference to the method and doctrine of the Angelic Doctor. Quite other than exclusive preference, this deals with an
exemplary preference that permitted Leo XIII to declare it to be "inter Scholasticos Doctores, omnium princeps et magister" (Aeterni Patris,
no. 13). And truly such is St. Thomas Aquinas, not only for the completeness, balance, depth, and clarity of his style, but still more for his keen sense of fidelity to the truth, which can also be called realism. Fidelity to the voice of created things so as to construct the edifice of philosophy: fidelity to the voice of the Church so as to construct the edifice of theology.
Exemplary Model of Theological Research
Faithfulness to the voice of things, in philosophy, corresponds, according to St. Thomas, to, faithfulness to the voice of the Word of God
transmitted by the Church in theology. And its rule, which never fails, is the principle: "Magis standum est auctoritati Ecclesiae...quam cuiuscumque Doctoris" (S. Theol. II-IIae, q. 10, a. 12). Truth, suggested by the
authority of the Church assisted by the Holy Spirit, is therefore the measure of truth as expressed by all the theologians and doctors—past, present and future. The authority of St. Thomas' doctrine is here resolved and
replenished in the authority of the Church's Doctrine. That is why the Church has proposed it as an exemplary model of theological research.
In theology, too, St. Thomas therefore prefers not the voice of
the Doctors or his own voice, but that of the Universal Church, almost anticipating what Vatican II says: "The totality of the faithful who have received the unction of the Holy Spirit cannot be mistaken in believing" (
Lumen gentium, no. 12); "When both the Roman Pontiff and the body of the bishops with him define a doctrinal point, they do it in accordance with revelation itself, which everyone must stay with and conform to" (
Lumen gentium, no. 25).
It is not possible to review all reasons that induced the Magisterium of the Church to choose St. Thomas as a sure guide in theological and philosophical disciplines; but
one is doubtless this: his having set the principles of universal value which bear out the relationship between reason and faith. Faith contains the values of human wisdom in a superior, different, and eminent way:
therefore it is impossible for reason to be in disagreement with faith, and if in disagreement, it is necessary to look at and reconsider the conclusions of philosophy: In this sense faith itself becomes a priceless aid
The recommendation of Leo XIII is still valid: "Qua propter qui philosophiae studium cum obsequio fidei christianae coniungun, ii optimae philosophantur: quandoquidem divinarum veritatum
splendor, animo exceptus, ipsam juvat intelligentiam; cui non modo nihil de dignitate detrahit, sed nobilitatis, accuminis, firmitatis plurimum addit" (Aeterni Patris, no. 13).
theological truth converge into a single truth. Truth of reason goes back from creatures to God; truth of faith descends directly from God to man. But this diversity of method and origin does not take away their
fundamental oneness, because there is a single identical Author of truth manifested through creation, and truth communicated personally to man by means of His Word. Philosophical research and theological research are
two different directions of movement of a single truth, destined to meet, but not to collide, on the same road, in order to help each other. Thus reason, illuminated, strengthened, and guaranteed by faith, becomes a
faithful companion of faith itself, and faith immensely widens the limited horizon of human reason. On this point St. Thomas is truly an enlightening teacher: "Quia vero naturalis ratio per creaturas in Deo cognitionem
ascendit; fidei vero in nos, e converso, divina revelatione descendit, est autem eadem via ascensus et descendus, oportet eadem via procedere in his quae supra rationem credentur, qua in superioribus processum est circa
ea quae ratione investigantur de Deo" (Contra Gentiles, IV, 1 no. 3349).
The difference in the method and instruments of research greatly differentiates philosophical knowledge from theological. Even
the best philosophy, which is of the Thomist style, which Paul VI has so well defined as "natural philosophy of the human mind," flexible in listening and faithful in expressing the truth of things, is always
conditioned by the limits of intelligence and human language. However, the Angelic One does not hesitate to declare: "Locus ab auctoritate quae fundatur super ratione humana est infirmissimus" (S. Theol, I, q. 1, a. 8,
ad 2). Any philosophy, in that it is a product of man, has man's limits. On the contrary, "Locus ab auctoritate quae fundatur super revelatione divina est efficacissimus" (ibid). Divine authority is absolute; therefore,
faith enjoys the solidity and security of God himself; human science always has man's weakness, to the extent that it is founded upon man. Yet even in philosophy there is something absolutely true, unfailing and
necessary: its first principles, the foundation of every knowledge.