Organism and Environment performs an examination into the way the contemporary life sciences are heralding a revolution of the most basic philosophical concepts of the Western world. Analyzing recent research in microbiology and evolution theory, the present book argues that these discourses are adding their voices to a growing chorus which is announcing a disruption, if not an end, to the understanding of the order of the world articulated in humanism. What does it mean to be a living substance? Are there such things as living individuals? How are living beings free? The discourses of microbiology, the medical sciences and evolution theory are revealing a living organism that escapes the limited frame that Enlightenment humanism has traditionally used to answer these (and other) ontological questions. Appealing to the theoretical lenses provided by Michel Foucault, Hans Georg Gadamer and Gilles Deleuze, Organism and Environment offers an interpretation of the way the contemporary life sciences are giving articulation to a posthuman ontological order.