From Pope St. John Paul II’s encyclical Fides et Ratio (1984):
The First Vatican Council teaches, then, that the truth attained by philosophy and the truth of Revelation are neither identical nor mutually exclusive: “There exists a twofold order of knowledge, distinct not only as regards their source, but also as regards their object. With regard to the source, because we know in one by natural reason, in the other by divine faith. With regard to the object, because besides those things which natural reason can attain, there are proposed for our belief mysteries hidden in God which, unless they are divinely revealed, cannot be known”.7 Based upon God’s testimony and enjoying the supernatural assistance of grace, faith is of an order other than philosophical knowledge which depends upon sense perception and experience and which advances by the light of the intellect alone. Philosophy and the sciences function within the order of natural reason; while faith, enlightened and guided by the Spirit, recognizes in the message of salvation the “fullness of grace and truth” (cf. Jn 1:14) which God has willed to reveal in history and definitively through his Son, Jesus Christ (cf. 1 Jn 5:9; Jn 5:31-32).
Contemplating Jesus as revealer, the Fathers of the Second Vatican Council stressed the salvific character of God’s Revelation in history, describing it in these terms: “In this Revelation, the invisible God (cf. Col 1:15; 1 Tim 1:17), out of the abundance of his love speaks to men and women as friends (cf. Ex 33:11; Jn 15:14-15) and lives among them (cf. Bar 3:38), so that he may invite and take them into communion with himself. This plan of Revelation is realized by deeds and words having an inner unity: the deeds wrought by God in the history of salvation manifest and confirm the teaching and realities signified by the words, while the words proclaim the deeds and clarify the mystery contained in them. By this Revelation, then, the deepest truth about God and human salvation is made clear to us in Christ, who is the mediator and at the same time the fullness of all Revelation”.8
5 Dogmatic Constitution on the Catholic Faith Dei Filius, IV: Denzinger, Heinrich, and Adolf Schönmetzer, Enchiridion symbolorum definitionum et declarationum de rebus fidei et morum, 3015; quoted also in Second Vatican Ecumenical Council, Pastoral Constitution on the Church in the Modern World Gaudium et Spes, 59.
6 Dogmatic Constitution on Divine Revelation Dei Verbum, 2.
— Fides et Ratio 9-10