The history of late-19th-century socialism tends to focus on the rise of more extreme forms, especially Marxism. This approach marginalizes the more moderate and yet no less powerful and influential forms of socialism, particularly those developed by philosophers who were also political activists. This article seeks to rectify this situation to some extent. Section two reconstructs Ritchie's liberal socialism and relates it to his endorsement of the Fabian policy of 'permeation'. Section three develops this analysis by exploring Ritchie's claim that the philosophical historian should unlock past ideological configurations by using 'critical metaphysics' and 'speculative metaphysics' to analyse the gradual social 'emanation' of the higher principles of knowledge as those coalesced in the writings of 'representative men'. Section four focuses on political theory, by reconstructing Ritchie's analysis of Locke's theory of private property and the liberal socialist intimations that Ritchie drew from it. It is concluded that while Ritchie's liberal socialism remains an underappreciated ideological position and his critical method remains controversial, both should retain interest for the intellectual historian.