 While keeping much of the language of Kant, Hermann von Helmholtz, among others, worked to change the questions being asked in Kant’s name and the methods used to find answers to these questions. It is not easy to assess the degree of continuity between the strands of neo-Kantianism that emerged and Kant’s own interests. Lange is sometimes taken as the founder of the Marburg School of neo-Kantianism. Perhaps it would be more accurate to say that Lange was a mentor of the first famous member of the Marburg School, Hermann Cohen. The other well-known members were Paul Natorp and Ernst Cassirer. The appendices of the second volume of Holzhey (1986) contains Cohen’s correspondence, including some correspondence between Cohen and Lange. In general, Holzhey (1986) is an excellent source of information on the foundation of the Marburg School, as is Sieg 1994. Holzhey and Buée (2011) and Holzhey (2005) explore the relationship between Cohen and Lange. Karl Vorländer published a review of Cohen’s lengthy “Introduction” to Lange’s History of Materialism in 1897, in Kant-Studien. Vorländer’s brief review nonetheless sets out a number of differences of method and conclusion between Cohen and Lange. In many ways Hermann Cohen returned to a conception of the basic questions of epistemology that was closer to Kant’s, one Vorländer calls “critical idealism”. Lange, on the other hand, drew on Helmholtz’s early thought to conclude that the scientific investigation of the physiology of the sense organs provided partial confirmation of Kant’s fundamental claims.