What does it mean to speak for nature? Contemporary environmental critics warn that giving a voice to nonhuman nature reduces it to a mere echo of our own needs and desires; they caution that it is a perverse form of anthropocentrism. And yet nature's voice proved a powerful and durable ethical tool for premodern writers, many of whom used it to explore what it meant to be an embodied creature or to ask whether human experience is independent of the natural world in which it is forged.

The history of the late medieval period can be retold as the story of how nature gained an...