In “The Climate of History: Four Theses,” Dipesh Chakrabarty examined the idea of the Anthropocene—the dawn of a new geological period dominated by human activities—in the context of history and philosophy, raising fundamental questions about how we think historically in an era when human and geological timescales are colliding. Developing out of a 2015 workshop, this volume of RCC Perspectives offers critiques of these “Four Theses” by scholars of environmental history, political philosophy, religious studies, literary criticism, environmental planning, geography, law, biology, and geology. The essays suggest many ways in which Chakrabarty’s arguments both reflect and further catalyze an ongoing transformation in intellectual culture and research on environment and society in the Anthropocene. The volume concludes with a response to the essays from Chakrabarty himself.