As a student, I wondered why the eighth century monk Fridugisus of Tours read the Bible to prove the existence of shadows when he could see shadows on the page. In his letter to Charlemagne, “On the Being of Nothing and Shadows,” Fridugisus deduces shadows from Genesis 1:2: “And the shadows were over the face of the deep.” To demonstrate that shadows move, he turns to Psalms 105:28: “He sent shadows.” Fridugisus thinks this better evidence than the shadow he sent by turning the page.
