In the face of growing skepticism and relativism, "believe in reason" is the central message in Pope John Paul II's Fides et Ratio. Only by the two wings of reason and faith together can the human spirit soar. The current work, Ratio et Fides, is its philosophical counterpart. It is not a watered-down introduction but a "leading-into" the heart of philosophic thinking. Firmly rooted in the phenomenological description of an ordinary artifact, a mailbox,...