 Lange’s most famous book, The History of Materialism and Critique of its Contemporary Significance, is in essence a defense of such a return to Kant. It is also a detailed history of materialism (and was read well into the twentieth century for precisely this reason). More fundamentally, The History of Materialism was meant to drive home the above-mentioned concerns. Lange accepted materialism as a sensible maxim for the construction of theories within natural science. However, as a comprehensive philosophical system, as both fundamental ontology and epistemology, materialism is self-undermining.