Centred on 'Foams', the third volume of his Spheres trilogy, this article questions the privilege granted by Peter Sloterdijk to motifs of inclusion and exclusion, contending that whilst his prioritization of dwelling as a central aspect of human existence provides a promising counterpoint to the dislocative and isolative effects of post-industrial capitalism, it is compromised by its dependence upon an anti-cosmopolitan outlook that views cultural distantiation as a natural and preferable state of human affairs, and valorizes a purported ontological security (...) attained through defensive postures with respect to perceived foreigners or externalities. Sloterdijk’s conceptualization of culture as a kind of immune system, it is argued, although posited as a rebuke to models of essentialism and ethno-nationalism, provides ontological support to the xenophobic critiques of immigration that are today finding increasing currency. (shrink)