Hans Kayser's 'Lehrbuch der Harmonik': An annotated translation of the preface and introduction, together with a critical evaluation of Kayser's contribution and influence

Hans Kayser's Lehrbuch der Harmonik (pub. 1950) represents the summation of thirty years of research in the interdisciplinary field of Harmonics, which weds Pythagorean harmonical proportions with modern scientific methodologies and metaphysical speculation. In the introduction to the Lehrbuch, Kayser first traces throughout history the acoustic element (acroasis, the aural contemplation of the world) in world religion and mythology, philosophy, language, literature, hymnology, astronomy, architecture, and poetry. He then presents Harmonics as a science of the ear and considers its relevance to physics, acoustics, and music theory. Harmonics is described as a theory of correspondence, and an argument is made in support of “correspondence thinking” as a valid means for gaining knowledge that should coexist with scientific, causal thinking. Finally, thought is defined as a sense that is a function of the brain (just as hearing is a function of the ear) and all of the senses (including thought) are considered subservient to the spirit, the source of ideas.; Kayser uses as a tool for harmonical research the Pythagorean Table, a diagram which pairs multiple overtone series with their reciprocals, in order to demonstrate the presence of harmonical proportions in nature and in the human soul or psyche. Harmonics, which uses the monochord as its primary research instrument, is presented both as a scientific, academic discipline and as a spiritual practice that can relieve the pressures of modern life by leading its practitioners toward “an immersion…into the reality and essence of things.” Kayser's contribution can be summarized as follows: he distilled and preserved what he believed to be the essence of Pythagoreanism and liberated it from its historical inflection by recasting it as a modern scientific discipline. Although Kayser's attempt to demonstrate the relevance of Pythagorean thought to his contemporaries met with only limited success during his lifetime, his influence can now be traced in the fields of harmonical research, musicology, music theory, architecture, literature, symbology, medicine, music therapy, and sound therapy. Recent developments in sound therapy and other fields have helped create an environment in which Kayser's significance might be reassessed.