The paper focuses on the role of relativistic ideas in Wittgenstein’s philosophy. In particular, it focuses on On Certainty (1969), where in (305), Wittgenstein explicitly invokes Einstein’s theory of relativity: “Here once more there is needed a step like the one taken in relativity theory.” The aim of the paper is to establish a connection between Wittgenstein and Einstein that is both theoretically and exegetically sound. In particular, the paper argues that Wittgenstein’s reaction to scepticism closely resembles Einstein’s reaction to (...) the ether. (shrink)