This paper argues that the ‘scientific dispute’ between Hermann Cohen and Rudolf Stammler is symptomatic of a philosophical movement of left-wing Kant interpretations at the turn of the twentieth century. By outlining influential predecessors that shaped Cohen’s and Stammler’s thinking, I show that their Kantian justifications of socialism differ regarding their conception of law, history, and the political implications that follow from their practical philosophies. Against scholars who suggest that the Marburg School’s view on socialism was a coherent school of (...) thought, I introduce the concept of ‘left-Kantianism’ as an open term that includes a wide variety of novel socialist approaches to Kant at the time. (shrink)