For much of the modern period, theologians and philosophers of religion have struggled with the problem of proving that it is rational to believe in God. Drawing on the thought of Thomas Aquinas, this book, a companion to Theological Philosophy, lays the foundation for an innovative effort to overturn the longstanding problem of proving faith's rationality, and to establish instead that rationality requires to be explained by appeals to faith. To this end, Schumacher advances the constructive argument that rationality is not only an epistemological question concerning the soundness of human thoughts, which she defines in terms of 'intellectual virtue'.