From Pope St. John Paul II’s encyclical Fides et Ratio (1984):
More than a hundred years after the appearance of Pope Leo XIII’s Encyclical Æterni Patris, to which I have often referred in these pages, I have sensed the need to revisit in a more systematic way the issue of the relationship between faith and philosophy. The importance of philosophical thought in the development of culture and its influence on patterns of personal and social behaviour is there for all to see. In addition, philosophy exercises a powerful, though not always obvious, influence on theology and its disciplines. For these reasons, I have judged it appropriate and necessary to emphasize the value of philosophy for the understanding of the faith, as well as the limits which philosophy faces when it neglects or rejects the truths of Revelation. The Church remains profoundly convinced that faith and reason “mutually support each other”;122 each influences the other, as they offer to each other a purifying critique and a stimulus to pursue the search for deeper understanding.
A survey of the history of thought, especially in the West, shows clearly that the encounter between philosophy and theology and the exchange of their respective insights have contributed richly to the progress of humanity. Endowed as it is with an openness and originality which allow it to stand as the science of faith, theology has certainly challenged reason to remain open to the radical newness found in God’s Revelation; and this has been an undoubted boon for philosophy which has thus glimpsed new vistas of further meanings which reason is summoned to penetrate.
Precisely in the light of this consideration, and just as I have reaffirmed theology’s duty to recover its true relationship with philosophy, I feel equally bound to stress how right it is that, for the benefit and development of human thought, philosophy too should recover its relationship with theology. In theology, philosophy will find not the thinking of a single person which, however rich and profound, still entails the limited perspective of an individual, but the wealth of a communal reflection. For by its very nature, theology is sustained in the search for truth by its ecclesial context123 and by the tradition of the People of God, with its harmony of many different fields of learning and culture within the unity of faith.
122 First Vatican Ecumenical Council, Dogmatic Constitution on the Catholic Faith Dei Filius, IV: Denzinger, Heinrich, and Adolf Schönmetzer, Enchiridion symbolorum definitionum et declarationum de rebus fidei et morum 3019.
123 “Nobody can make of theology as it were a simple collection of his own personal ideas, but everybody must be aware of being in close union with the mission of teaching truth for which the Church is responsible”: John Paul II, Encyclical Letter Redemptor Hominis (4 March 1979), 19: Acta Apostolicæ Sedis 71 (1979), 308.
— Fides et Ratio 100-101