Fides et Ratio §73

⁷³ In the light of these considerations, the relationship between theology and philosophy is best construed as a circle. Theology's source and starting-point must always be the word of God revealed in history, while its final goal will be an understanding of that word which increases with each passing generation. Yet, since God's word is Truth (cf. Jn 17:17), the human search for truth—philosophy, pursued in keeping with its own rules—can only help to understand God's word better. It is not just a question of theological discourse using this or that concept or element of a philosophical construct; what matters most is that the believer's reason use its powers of reflection in the search for truth which moves from the word of God towards a better understanding of it. It is as if, moving between the twin poles of God's word and a better understanding of it, reason is offered guidance and is warned against paths which would lead it to stray from revealed Truth and to stray in the end from the truth pure and simple. Instead, reason is stirred to explore paths which of itself it would not even have suspected it could take. This circular relationship with the word of God leaves philosophy enriched, because reason discovers new and unsuspected horizons.