Hermann Cohen’s Kants Theorie der Erfahrung helped set the agenda for Marburg Neo‑Kantianism by treating Kant as a philosopher of the conditions that make modern science possible. This “back to Kant” approach became a key starting point for later Kantian revivals in ethics and moral theory. It also encouraged reading Kant as a living method rather than a closed historical system.
Heinrich Rickert’s Die Grenzen der naturwissenschaftlichen Begriffsbildung (first appearing in parts from 1896 into the early 1900s) developed a Neo‑Kantian account of how different sciences form concepts. By contrasting natural science (generalizing) with historical and cultural inquiry (individualizing), it strengthened the idea that normativity and “value‑relevance” matter for understanding human life. This work helped create a climate in which ethical theory could be treated as rigorous, not merely psychological or sociological.
Hans Vaihinger founded Kant‑Studien to support specialized research on Kant and related movements. The journal became an important forum where Neo‑Kantian and later Kantian approaches—especially debates about ethics, law, and practical reason—could develop across institutions. It also helped turn Kant scholarship into a durable, organized research field.
Paul Natorp’s Sozialpädagogik argued that education and moral formation depend on community life and shared social practices. Within the Marburg circle, this helped connect Kantian ethics to questions about social institutions and collective responsibility, not only individual duty. It also set up later debates about how universal moral principles relate to historical and cultural life.
In Ethik des reinen Willens, Cohen developed an ambitious Neo‑Kantian moral theory that emphasizes the role of “pure will” and rational norms in ethical life. The work aimed to defend the objectivity of moral obligation without grounding it in psychology or mere social convention. It became a major reference point for early 20th‑century debates about whether Kantian ethics is only “formal” or can guide real moral and political life.
The Kant‑Gesellschaft (Kant Society) was founded in Halle in 1904, strengthening the organizational base of Kant scholarship. It supported publications and lectures and relied heavily on Kant‑Studien as a key platform. This institutional infrastructure helped sustain Kantian moral philosophy through the upheavals of the early 20th century.
Max Scheler’s Der Formalismus in der Ethik und die materiale Wertethik (published across 1913–1916) criticized Kantian ethics for focusing too much on the form of duty and not enough on the content of values. Scheler argued that people can “grasp” values in experience and that moral life has richer structure than rule‑following alone. Even when rejecting Kant’s approach, the book kept Kantian ethics at the center of debate and forced Neo‑Kantians to clarify what their ethics could explain.
Hermann Cohen died in 1918, near the end of World War I and just before the Weimar Republic era of German intellectual life. With Cohen gone, Marburg Neo‑Kantianism no longer had its central founder, and later thinkers increasingly reworked Kantian themes rather than extending Cohen’s system directly. This shift helped open space for new “revivals” of Kantian moral philosophy in different styles.
Ernst Cassirer’s Philosophie der symbolischen Formen began appearing in 1923, with later volumes in 1925 and 1929. Cassirer moved beyond strict school Neo‑Kantianism by arguing that humans create meaning through “symbolic forms” such as language and myth, not only through scientific concepts. This broadened Kantian thinking toward culture and helped reshape how ethical and practical ideals might be understood in modern life.
Nicolai Hartmann’s Ethik (1926) offered a large, systematic moral philosophy centered on values and moral conflict. While not a straightforward Neo‑Kantian work, it developed in dialogue with Kantian and Neo‑Kantian debates about normativity and objectivity. The result helped keep deontological themes alive by arguing that moral requirements are not reducible to consequences or preferences.
W. D. Ross’s The Right and the Good (1930) set out a “pluralist deontology,” arguing that morality includes several basic duties (like keeping promises and avoiding harm) that can conflict. Ross’s account was not a revival of Kant in a narrow sense, but it renewed deontological ethics in the English‑speaking world by defending duty against theories that reduce right action to maximizing good outcomes. This broadened 20th‑century deontology beyond a single‑principle Kantian model.
A. J. Ayer’s Language, Truth, and Logic (1936) argued that many metaphysical claims are meaningless and treated moral judgments as expressions of emotion rather than statements of fact. This directly challenged Kantian and Neo‑Kantian views that ethics can be objectively grounded in reason. The book helped shift English‑language moral philosophy toward metaethics and set up later efforts to defend Kantian ethics against “noncognitivism” (the view that moral claims are not truth‑apt).
By the late 1930s, National Socialist control in Germany disrupted the work of the Kant‑Gesellschaft, and Kant‑Studien continued only irregularly until 1944. This period narrowed academic freedom and weakened the institutional networks that had supported Neo‑Kantian and Kantian ethical debate. The disruption helped shift much Kantian moral philosophy into exile and into post‑war rebuilding efforts.
World War II ended in Europe in 1945, bringing a major break in German academic life and forcing a reorganization of philosophical institutions. Many Kantian and Neo‑Kantian themes survived, but the center of gravity shifted as post‑war philosophy rebuilt journals, societies, and university life and responded to new political realities. The 1870–1945 period thus ends with both an institutional rupture and a transition to later, post‑1945 Kantian moral revivals.
Neo‑Kantian and 20th‑century Kantian revivals in moral philosophy (1870–1945)