For most European scholars, the scope of Comparative Theology is not very clear. They see big differences between the notion of Comparative Theology among its protagonists, e.g., between Keith Ward or Robert Neville and Francis Clooney or James Fredericks. That is why I will try to define a certain understanding of Comparative Theology which can be defended in accordance with strong European theological traditions. I want to show that Comparative Theology can be understood as one of the best fruits of liberal theology and of a Wittgensteinian interpretation of transcendental philosophy—and that it opens new perspectives for confessional theology. The current development of Islamic theology in Germany is especially challenging for Comparative Theology and the best opportunity to develop it into a project undertaken by scholars of different religions and different intellectual traditions. I will argue that Comparative Theology is not a new discipline within the old disciplines of theology, but that it can give new perspectives to all theological disciplines and thoroughly change their character.