Hostile prototypes: plastic urbanism in San Francisco

Turning to the concept of plasticity in the philosophy of Catherine Malabou, this article traces an approach to urban change as a volatile movement of giving, receiving and exploding form. It diverges from lines of thinking within cultural geography that affirm lively processes and relations, instead calling attention to the finite and fragile morphologies of cities and their exposure to the threat of destruction. The article examines a planning programme in San Francisco which invites local groups to craft and care for temporary street furniture. Intended to facilitate civic engagement, such artefacts acquire plastic properties that further divide and disrupt populations, particularly those experiencing homelessness. Attuning to this negative power of form illuminates an emerging hostile urbanism that utilises provisional structures to irreversibly alter the constitution of places.