The victory of realism over idealism at the start of the twentieth century, and of scientific realism over logical empiricism and pragmatism in the mid twentieth century, is a striking phenomenon that calls for historical explanation. In this paper I propose an externalist account, looking at the social and political reasons why realism became attractive, rather than considering the internal factors–the merits of the arguments in favour of realism. I look at the agenda of Roy Wood Sellars’ critical realism which (...) was not narrowly theoretical, but very much related to his concerns for the development of American society post WW1, as expressed in The Next Step in Democracy (1916b) and The Next Step in Religion (1918). I discuss the significance of technocracy in America – not only the increasing influence of scientists and engineers in government, but also the diffusion of the view that social issues are best addressed by scientific, technical means. Counter-cultural critics of technocracy, such as Roszak (1969) claimed that a “scientific world-view” provided an “ideology” for this system of governance. We will see that RW Sellars was explicitly involved in the task of building a scientific world-view, but with political goals that were probably not realised by the post-war establishment. (shrink)