Starting from the concept of the “sphere”, Sloterdijk’s three volumes move from small-scale relations between two or three people, to larger structures on the level of the globe and civilisation, and finally to fragmented, multi-centred structures in modern life. By using the sphere as a metaphor, he shows that individuals never exist alone, but always live within spaces shaped by “circles, bubbles, and spheres”.
The book discusses the boundaries that define the inside and outside of each sphere—how they include certain elements while excluding others. These spheres are not only physical spaces, but also ways of forming, maintaining, and organising relationships.