CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 38–41

38 This is why man stands in need of being enlightened by God's revelation, not only about those things that exceed his understanding, but also "about those religious and moral truths which of themselves are not beyond the grasp of human reason, so that even in the present condition of the human race, they can be known by all men with ease, with firm certainty and with no admixture of error".
39 In defending the ability of human reason to know God, the Church is expressing her confidence in the possibility of speaking about him to all men and with all men, and therefore of dialogue with other religions, with philosophy and science, as well as with unbelievers and atheists.
40 Since our knowledge of God is limited, our language about him is equally so. We can name God only by taking creatures as our starting point, and in accordance with our limited human ways of knowing and thinking.
41 All creatures bear a certain resemblance to God, most especially man, created in the image and likeness of God. The manifold perfections of creatures - their truth, their goodness, their beauty all reflect the infinite perfection of God. Consequently we can name God by taking his creatures" perfections as our starting point, "for from the greatness and beauty of created things comes a corresponding perception of their Creator".