The first two chapters of Love Alone are an interesting project. Von Balthasar is attempting a small history of western thought, basically on the idea of how and where Christianity gains it credibility: how is it believable. He breaks it down to two eras: the Ancient/Medieval (or Patristic/Scholastic) and the Modern. The first era saw the credibility--the "believableness"--of Christianity coming from the idea that Christ was the Logos. The Logos was what ancient and medieval thought recognized as the logic of the universe: the rational principle underlying all reality. This Logos, which was identified with God, is what became human in the person of Jesus of Nazareth. It all fit together nicely, but seemed to lose its power to persuade the culture at the rise of the modern world. The level of "nature" would come to be seen as entirely self-contained and self-justifying. It was a fundamental shift in popular consciousness to see order as a fundamental state or aspect of nature. Christianity could no longer appeal to the identification of Christ and his teachings with a transcendent reality accepted as a religiously-neutral fact (the Logos) as a way of demonstrating the truth of Christianity.
As a result, Christianity turns to another form of credibility, an anthropological one instead of a cosmological one, to use Von Balthasar's terms. Modernity's turn to man as the measure of all things is the new rule that Christianity must use to try to demonstrate its credibility. At root, however, this concept really clashes with Christian thinking--man isn't the measure of reality, and modernity strongly shakes Christianity's credibility for many people.
This is about as far as I've gotten in his text thus far. He's going to propose a new understanding, one that goes beyond both the cosmological and anthropological approaches. An ambitious undertaking! I know from the contents and title that this is going to be articulated in terms of "Love" and I'm really curious to see how he's going to do this in a way that would be different than a mere emphasis on affectivity--the feeling and experience of love--which was, in fact, a significant part of the "anthropological" approach in the movement of Pietism.