Fides et Ratio §67

⁶⁷ With its specific character as a discipline charged with giving an account of faith (cf. 1 Pet 3:15), the concern of fundamental theology will be to justify and expound the relationship between faith and philosophical thought. Recalling the teaching of Saint Paul (cf. Rom 1:19-20), the First Vatican Council pointed to the existence of truths which are naturally, and thus philosophically, knowable; and an acceptance of God's Revelation necessarily presupposes knowledge of these truths. In studying Revelation and its credibility, as well as the corresponding act of faith, fundamental theology should show how, in the light of the knowledge conferred by faith, there emerge certain truths which reason, from its own independent enquiry, already perceives. Revelation endows these truths with their fullest meaning, directing them towards the richness of the revealed mystery in which they find their ultimate purpose. Consider, for example, the natural knowledge of God, the possibility of distinguishing divine Revelation from other phenomena or the recognition of its credibility, the capacity of human language to speak in a true and meaningful way even of things which transcend all human experience. From all these truths, the mind is led to acknowledge the existence of a truly propaedeutic path to faith, one which can lead to the acceptance of Revelation without in any way compromising the principles and autonomy of the mind itself. Similarly, fundamental theology should demonstrate the profound compatibility that exists between faith and its need to find expression by way of human reason fully free to give its assent. Faith will thus be able “to show fully the path to reason in a sincere search for the truth. Although faith, a gift of God, is not based on reason, it can certainly not dispense with it. At the same time, it becomes apparent that reason needs to be reinforced by faith, in order to discover horizons it cannot reach on its own”.