From Pope St. John Paul II’s encyclical Fides et Ratio (1984):
In brief, there are signs of a widespread distrust of universal and absolute statements, especially among those who think that truth is born of consensus and not of a consonance between intellect and objective reality. In a world subdivided into so many specialized fields, it is not hard to see how difficult it can be to acknowledge the full and ultimate meaning of life which has traditionally been the goal of philosophy. Nonetheless, in the light of faith which finds in Jesus Christ this ultimate meaning, I cannot but encourage philosophers—be they Christian or not—to trust in the power of human reason and not to set themselves goals that are too modest in their philosophizing. The lesson of history in this millennium now drawing to a close shows that this is the path to follow: it is necessary not to abandon the passion for ultimate truth, the eagerness to search for it or the audacity to forge new paths in the search. It is faith which stirs reason to move beyond all isolation and willingly to run risks so that it may attain whatever is beautiful, good and true. Faith thus becomes the convinced and convincing advocate of reason.
Yet the Magisterium does more than point out the misperceptions and the mistakes of philosophical theories. With no less concern it has sought to stress the basic principles of a genuine renewal of philosophical enquiry, indicating as well particular paths to be taken. In this regard, Pope Leo XIII with his Encyclical Letter Æterni Patris took a step of historic importance for the life of the Church, since it remains to this day the one papal document of such authority devoted entirely to philosophy. The great Pope revisited and developed the First Vatican Council’s teaching on the relationship between faith and reason, showing how philosophical thinking contributes in fundamental ways to faith and theological learning.78 More than a century later, many of the insights of his Encyclical Letter have lost none of their interest from either a practical or pedagogical point of view—most particularly, his insistence upon the incomparable value of the philosophy of Saint Thomas. A renewed insistence upon the thought of the Angelic Doctor seemed to Pope Leo XIII the best way to recover the practice of a philosophy consonant with the demands of faith. “Just when Saint Thomas distinguishes perfectly between faith and reason”, the Pope writes, “he unites them in bonds of mutual friendship, conceding to each its specific rights and to each its specific dignity”.79
78 Cf. Encyclical Letter Æterni Patris (4 August 1879): Acta Apostolicæ Sedis 11 (1878-1879), 97-115.
79 Ibid., loc. cit., 109.
— Fides et Ratio 56-57