Against the background of postmodern philosophy, where human history is viewed as a stage where only texts and discourses, signifiers and metaphors play, Manuel DeLanda has drawn out a history of the millennium which emphasizes material and energetic processes. In these theories, biological and social forms are seen to emerge from within matter itself and the major transitions in human history (from nomadism to agriculture, from agriculture to industry) are portrayed as phase transitions, similar to those undergone by matter as it changes from gas to liquid to solid.