In this paper I consider Otto Neurath's late discussion of the political and social context of Plato's Republic, especially how Neurath conceived them in the 1940s. Neurath's argumentation is contrasted with the ideas of Karl Popper, both with regard to the latter's reading of Plato and to his general methodology. The distinction between Neurath's treatments of epistemology and politics is also discussed, by highlighting how these two were interwoven in the discussion, and how they differentiated Neurath's articles from Popper's considerations in the Open Society.