Paragraph 32. The world: starting from movement, becoming, contingency, and the world's order and beauty, one can come to a knowledge of God as the origin and the end of the universe. (54, 337)

As St. Paul says of the Gentiles: For what can be known about God is plain to them, because God has shown it to them. Ever since the creation of the world his invisible nature, namely, his eternal power and deity, has been clearly perceived in the things that have been made.

And St. Augustine issues this challenge: Question the beauty of the earth, question the beauty of the sea, question the beauty of the air distending and diffusing itself, question the beauty of the sky... question all these realities. All respond: "See, we are beautiful." Their beauty is a profession [confessio]. These beauties are subject to change. Who made them if not the Beautiful One [Pulcher] who is not subject to change?

Paragraph 37. In the historical conditions in which he finds himself, however, man experiences many difficulties in coming to know God by the light of reason alone: (1960)

Though human reason is, strictly speaking, truly capable by its own natural power and light of attaining to a true and certain knowledge of the one personal God, who watches over and controls the world by his providence, and of the natural law written in our hearts by the Creator; yet there are many obstacles which prevent reason from the effective and fruitful use of this inborn faculty. For the truths that concern the relations between God and man wholly transcend the visible order of things, and, if they are translated into human action and influence it, they call for self-surrender and abnegation. The human mind, in its turn, is hampered in the attaining of such truths, not only by the impact of the senses and the imagination, but also by disordered appetites which are the consequences of original sin. So it happens that men in such matters easily persuade themselves that what they would not like to be true is false or at least doubtful.