 He completed his degree in summer 1907 with his work “On the Problem of Being in Greek Philosophy before Plato” (Über das Seinsproblem in der griechischen Philosophie vor Plato, Hartmann 1908). His massive “Plato’s Logic of Being” (Platos Logik des Seins) and the shorter “Proclus Diadochus’ Philosophical Foundations of Mathematics” (Des Proklus Diadochus philosophische Anfangsgründe der Mathematik, Habilitation) appeared in 1909. All of these show the imprint of his Neo-Kantian teachers. Probably influenced by reading the phenomenologists, including Edmund Husserl (1859–1938) and Max Scheler (1874–1928); by the rediscovery of Christian Wolff (1679–1754) through the work of Hans Pichler (1882–1958); and finally, by rereading Aristotle, Kant, and Hegel during the period of a general Hegel renaissance, he began to break free of Neo-Kantianism (Harich 2000). While he was teaching in Marburg and publishing a number of shorter works that prefigure his later ideas, he was called to serve in WWI. Starting in 1914, he served as an interpreter and letter-censor. He spent time on the Eastern Front, and then returned to Marburg in 1918. By the time he returned to Marburg, Cohen had left for Berlin and Natorp’s influence was in decline, and he was greeted as their successor. By this time, however, he was also the furthest of any of their former students from the Neo-Kantian position (Harich 2000). Reflecting on his career, he declared 1919 the year he worked out his final approach to a “new ontology.”