Early in the nineteenth century, the planetary Earth emerged as a new object of fascination across the Western world, upending Biblical authority and intertwining the once-separate orders of human and natural history. The industrial and imperial energies released by the emergence of Earth into human consciousness launched chains of causality leading to the Anthropocene, chains that bind us to this earlier era even as the Anthropocene cuts us off from its grounding assumptions. As natural scientists from Buffon and Hutton to Humboldt, Lyell and Darwin elaborated Earth’s evolutionary development and the ecological interdependences of living systems, political economists wrestled with the resulting problem: Do human beings have planetary agency? Their epochal decision to admit such agency in theory even while denying it in practice would bequeath us an unresolved legacy of metaphysical terror – as well as a role for literary artists in reimagining the horizon of the human.