The German polymath Carl Stumpf (1848–1936) influenced one of the most significant philosophical developments of the early twentieth century: his student, Edmund Husserl, founded modern phenomenology. In a distinguished academic career spanning more than five decades, Stumpf also contributed to the growth of Gestalt psychology and ethnomusicology. An accomplished amateur musician, he used experimental methods to further the scientific study of music theory. His best-known work, first published in two volumes between 1883 and 1890, rigorously investigates the psychology of tone and music, ranging in coverage from physiology to acoustics. Its aim is to elucidate the effect that sounds have on various psychological functions. Volume 1 is divided into two sections. In the first, Stumpf describes the types of decision made by the human mind. In the second, he attempts to explain the connection between specific sounds and the decision-making process.