This text is the extended version of the speech that Heidegger addressed during the ceremony in honour of the Swiss psychiatrist Ludwig Biswanger (1881-1966). Biswanger is the founder of the so called “Daseins-analyse” (“existential analysis”). He had been strongly influenced by the conception of the “Dasein” presented by Heidegger in Being and Time, and had conceived his own project as a scientific anthropology aiming to disclose human essence. Here, Heidegger is critically appraising  Bis-wanger’s project in focusing on the relationship between philosophy and science.