I present a novel anti-sceptical BIV argument by focusing on conditions on the production and use of the locative preposition ‘in’. I distinguish two uses of ‘in’—material and descriptive phenomenological—and I explain in what respect movement is central to the concept that our use of ‘in’ expresses. I go on to argue that a functionalist semantics of the intelligible use of ‘in’ demands a materialist philosophy of action in the spirit of G.E.M. Anscombe, but also why the structure of space (...) is not irrelevant either; appeal to the structure of space unsettles the causal-empirical assumptions that ground the picture of subjectivity and agency that the biv narrative assumes. Finally, I explain why a functionalist semantics demands a Naïve Realist metaphysics of perception, consistent with some of Putnam’s last writings on philosophy of perception. (shrink)