Emil Kraepelin (February 15, 1856 - October 7, 1926) was a German psychiatrist and has been called the founder of modern scientific psychiatry, as well as of psychopharmacology and psychiatric genetics. Kraepelin believed the chief origin of psychiatric disease to be biological and genetic malfunction. While Kraepelin tried to find organic causes of mental illness, he adopted many theses of positivist medicine, but the basis for understanding is not etiology, as the causes of madness cannot be established with any precision. His theories dominated psychiatry at the start of the twentieth century and appeared to enjoy a revival at century's end.