Abstract

My primary goal in this paper is to provide a historical reconstruction of Heidegger’s relationship with Hermann Lotze’s logic of validity. Lotze’s characterization of truth's ‘actuality’ solidifies the fallacious presupposition that the essence of truth is to be understood primarily in terms of logical assertions. Heidegger marks this decisive position in §44 of Being and Time and gains its methodological purchase through the deconstruction of traditional logic. However, Heidegger’s treatment is abbreviated, and his sources remain notoriously concealed. For this reason, much is to be gained by examining the supplement provided one year earlier in a lecture course titled Logic: The Question of Truth. In this course, Heidegger critically evaluates a core principle of both phenomenology and neo-Kantian Erkenntnistheorie: the concept of validity (Geltung). This term originates from Lotze’s Platonic Ideenlehre, which asserts that Platonic "ideas" correspond to thoughts by means of a logical necessity. Throughout this paper, I demonstrate the historical significance and influence of Lotze’s Logic on 20th-century Neo-Kantianism and Phenomenology. By returning to Lotze’s text, I also provide an in-depth review of Heidegger’s reading of Lotze, whom he charges with misleading 20th-century epistemology.