A friend of mine asks me today what the Catholic stand on man's ability to comprehend God is. What came to mind was the following from the Catechism:

Man's faculties make him capable of coming to a knowledge of the existence of a personal God. But for man to be able to enter into real intimacy with him, God willed both to reveal himself to man, and to give him the grace of being able to welcome this revelation in faith.(so) The proofs of God's existence, however, can predispose one to faith and help one to see that faith is not opposed to reason. (CCC 35)