In recent literature, it has been suggested that Lange’s social and political philosophy is separate from his neo-Kantian program. Prima facie, this interpretation makes sense given that Lange argues for an account of social norms that builds on Darwin and Smith rather than on Kant. Still, this paper argues that elements of psychophysiological transcendentalism can be found in Lange’s social and political philosophy. A detailed examination of the second edition of the History of Materialism, Schiller’s Poems, and the second edition of The Worker’s Question reveals that Lange sought to develop a systematic foundation of psychophysiological transcendentalism that is presupposed in his social and political philosophy. This allows for a more detailed understanding of Lange’s practical philosophy and assures him a position in the tradition of neo-Kantian socialism.