Anselm of Canterbury is an important and early source of two key themes in Western thought and religion that are hard to reconcile. In his arguments based only on reason, Anselm develops a model of pure and neutral rationality. In his intensely personal and passionate prayers, meditations, and letters of spiritual direction, Anselm is the forerunner of later experiential and emotional spirituality. Scholars have been largely content to compartmentalize these different elements in Anselm, but his most famous works, the Monologion and Proslogion, are both prayerful meditations and argumentative...