This article explores musical instruments as a source for the historical study of music theory. The figure of Pythagoras, and his alleged penchant for the monochord, offers a way into this exploration of the theory-bearing dimensions of instruments. Musicians tend to think of instruments primarily in terms of music-making, but in other contexts instruments are, more broadly, tools. In the context of scientific experimentation, specifically, instruments help researchers come to terms with “epistemic things”—objects under scrutiny that carry specific (but as yet unknown) sources of knowledge within them. Aspects of this experimental practice can productively be transferred to the study of music theory and are explored in two test cases from different periods of musical theorizing (and instrument building): Nicola Vicentino’s archicembalo from mid-sixteenth century Italy, and Henry Cowell’s rhythmicon from early twentieth-century America.
