34 This truth, which God reveals to us in Jesus Christ, is not opposed to the truths which philosophy perceives. On the contrary, the two modes of knowledge lead to truth in all its fullness. The unity of truth is a fundamental premise of human reasoning, as the principle of non-contradiction makes clear. Revelation renders this unity certain, showing that the God of creation is also the God of salvation history. It is the one and the same God who establishes and guarantees the intelligibility and reasonableness of the natural order of things upon which scientists confidently depend, and who reveals himself as the Father of our Lord Jesus Christ. This unity of truth, natural and revealed, is embodied in a living and personal way in Christ, as the Apostle reminds us: “Truth is in Jesus” (cf. Eph 4:21; Col 1:15-20). He is the eternal Word in whom all things were created, and he is the incarnate Word who in his entire person reveals the Father (cf. Jn 1:14, 18). What human reason seeks “without knowing it” (cf. Acts 17:23) can be found only through Christ: what is revealed in him is “the full truth” (cf. Jn 1:14-16) of everything which was created in him and through him and which therefore in him finds its fulfilment (cf. Col 1:17).
Source: Fides et Ratio (Vatican.va)