Leibsein

LeibSein, also written Leibsein or Leib-Sein, is a German term used in phenomenology and existential philosophy to denote bodily existence or the lived body. It emphasizes that a person experiences their own body from the first person, not merely as an external object but as the medium through which action, perception, and intentionality are carried out.

In usage, Leibsein is often connected to distinctions between Leib and Körper: Leib refers to the body as it is lived from within, while Körper denotes the body as an object in the external world. Related terms such as Leiblichkeit describe the structured, lived character of embodiment.

The concept appears in discussions of how being-in-the-world is inseparable from one's bodily presence. In phenomenology, the body is not a mere thing among things but a necessary condition of subjectivity. In much of Heideggerian analysis of Dasein and in Maurice Merleau-Ponty’s writings on perception, the body is fundamental to how beings engage with their surroundings. The idea also figures in other approaches to embodiment within contemporary philosophy and cognitive science, where attention is given to the unity of mind, action, and body in lived experience.

Leibsein is used to address questions about how persons know, move, and act from a first-person standpoint, and how embodiment shapes consciousness, agency, and interaction with the world. It remains a clarifying concept within discussions of phenomenology, embodiment, and related interdisciplinary fields.