At the University of Vienna, Hayek earned doctorates in law and political science in 1921 and 1923 respectively; and he also studied philosophy, psychology, and economics. For a short time, when the University of Vienna closed, Hayek studied in Constantin von Monakow's Institute of Brain Anatomy, where Hayek spent much of his time staining brain cells. Hayek's time in Monakow's lab, and his deep interest in the work of Ernst Mach, inspired Hayek's first intellectual project, eventually published as The Sensory Order (1952). It located connective learning at the physical and neurological levels, rejecting the "sense data" associationism of the empiricists and logical positivists. Hayek presented his work to the private seminar he had created with Herbert Furth called the Geistkreis.