5Fundamental Theology examines the light by which the mysteries of Christ and the Church, the Trinity and the Sacraments, are revealed to us. That light we call "revelation," and fundamental theology examines in the first place what this light shows about itself, and how it is sustained in the world. Or again, fundamental theology considers what the word of God has to say both about itself and what it has to say about where in the world it is to be heard. So, first it is a theology of Revelation (chapter 1), and second, a theology of the transmission of Revelation in Tradition, Scripture, and the Church (chapters 2, 3, and 4). Why must Revelation have the shape it does, and why must it be constituted by both word and event? Why is Tradition prior to Scripture, why must the word of God be written down, and why must Scripture come to us in two testaments? And why must the message conveyed in Tradition and Scripture have a living interpreter in the Church?

Since no word is spoken unless it is heard, fundamental theology also investigates the conditions of hearing the word of God, the very hearing itself in the assent of faith, and a necessary consequence of this hearing. The remote conditions of hearing are also what theology calls our ability to come to the knowledge of the preambula fidei- the things about God than can be known by the natural light (chapter 5). The immediate condition of hearing is the credibility of the word (chapter 6). Hearing is faith (chapter 7). And true hearing gives the hearer to recapitulate what is heard in his own wondering and thankful voice in theology (chapter 8). The introduction to theology in the last chapter is by way of considering the history of Catholic theology in the 20th century.