In the 20th century biology the concept of symbiosis was understood as a certain mode of living among others. The notion of the holobiont - popularized by Lynn Margulis - points out that symbiosis is rather the fundamental condition of life. Holobiont describes a symbiotic union of different species that together constitute a new organism and are vital for its maintenance.

A well-known example is the interdependence of human cells and bacteria in the intestine. In addition, however, human beings are populated by bacteria on the skin, in the mouth and generally everywhere else, keeping humans healthy and alive.

Following this example the concept of the individual cannot be maintained: The individual [from Latin: individuus, indivisible] promotes the idea of an autonomous and homogeneous organism. On the other hand, the concept of the holobiont, which expresses the heterogeneity of the organism and its dependence on its symbionts, is a different matter.

In her master's thesis, Lena Reitschuster traces the history of concepts and ideas surrounding the holobiont since the end of the 19th century. In the context of the climate crisis, the term gained importance in both biology and philosophy and stands for the search for a new way of thinking about the relationship between human and non-human actors.

Thus, Lena Reitschuster‘s master’s thesis analyzes the holobiont’s transformative political potential, giving deep insights into ideological premises in the history of biology, but also pointing at the need to rewrite history, if we aim at fundamentally changing our current mode of existence.