Content-externalism is the view that a subject’s relations to a context can play a role in individuating the content of her mental states. According to social content-externalists, relations to a socio-linguistic context can play a fundamental individuating role. Åsa Wikforss has suggested that ‘social externalism depends on the assumption that individuals have an incomplete grasp of their own concepts’ (Wikforss 2004, p. 287). In this paper, I show that this isn’t so. I develop and defend an argument for social content-externalism (...) which does not depend on this assumption. The argument is animated by strands of thought in the later work of Wittgenstein. In addition to demonstrating that social externalists are not necessarily committed to thinking that a subject can have thoughts involving concepts which she incompletely understands, this argument is important insofar as it: (1) supports a form of content-externalism with extended scope; (2) avoids the controversy surrounding the claim that subjects can think with concepts which they incompletely understand; and (3) situates Wittgenstein’s later work with respect to contemporary debates about content-externalism. (shrink)