On Harmonic “Progressions”and Infinite Quantities in the Music Theory of Leonhard Euler Roger Mathew Grant Assistant Professor and Fellow, Society of Fellows, University of Michigan Leonhard Euler (1707–1783) Coincidence Theories of Consonance 2:3 1:1 Coincidence Theories of Consonance 1585 1619 1636 Benedetti Kepler Mersenne 1739 Euler I. Coincidence Theories of Consonance II. Euler on Infinite “Progressions” III. Euler’s Historiography of Music Theory IV. Euler and the Future of Musical Thought The Harmonic Series 1 : 2 : 3 : 4 : 5 : 6 : 7 : 8 : 9 : 10 : 11 : 12: 13: 14: 15: 16 2:3 1:1 Coincidence Theories of Consonance 1585 1619 1636 Benedetti Kepler Mersenne 1692 1739 Euler Boethian Quadrivium Continuous Discrete Geometry Arithmetic Astronomy Music Gioseffo Zarlino Le istitutioni harmoniche (1558) “Number is a multitude composed of many Ones” Il Numero essere moltitudine composta di più unità “One is not a number, though it is the origin of number” La quale unità ben che non sia numero, tuttavia è del numero “The unison is only the origin of consonance or of interval; but it is neither a consonance nor an interval” l’Unisono è solamente principio della consonanza, o dell’Intervallo ma non è consonanza, ne intervallo Reception of Algebra François Viète Reception of Algebra Continuous Discrete Variables Variables Reception of Algebra Simon Stevin Marin Mersenne Harmonie universelle (1637) 1:1 2:1 3:1 4:1 5:1 6:1 8:1 9:1 10:1 12:1 15:1 16:1 Nature…prefers to break up the series of its intervals and melodies, rather than passing through an interval which will only hurt the ear and mind. La nature qui est harmonique, la reiette & ayme mieux romper la suite de ses intervalles & de ses chansons, que de passer par un interval qui ne vaut rien, que pour blesser l’oreille & l’esprit. 720 360 240 180 144 120 100 90 80 1⁄ 1⁄ 1⁄ 1⁄ 1⁄ 1⁄ 1⁄ 1⁄ … 1 2 3 4 5 6 7 8 72 67.5 60 in infinitum Francis Robartes (1692) 54 50 48 45 Coincidence Theories of Consonance 1585 1619 1636 Benedetti Kepler Mersenne 1692 1739 Euler II. Euler on Infinite “Progressions” III. Euler’s Historiography of Music Theory 4:7 Johann Philipp Kirnberger Flute Sonata in G Major (1769) Johann Philipp Kirnberger Clavierübungen (1766) I count the ratio 4:7 among the consonant intervals; it exists as certainly as 1:2... We know that one of the greatest scholars of our times, Leonhard Euler, has written about this ratio. IV. Euler on the Future of Musical Thought Fontenelle, “Sur l’application des sons harmoniques aux jeux d’orgues” (1742) This new consideration of the relationship of sounds is not only more natural because it is none other than the same series of numbers that are multiples of unity, but also because it conveys and represents all the music and the only music that nature gives to us by itself without the aid of art… It therefore seems that every time nature makes by itself, so to speak, a system of music, she does not employ anything but this species of sounds— however, they have remained, until the present, unknown in the theory of the musicians. Condillac, La langue des calculs (c. 1780) Here is the advantage that algebra will have: it will allow us to speak like nature. Condillac, on the development of a mathematical philosophy: The characteristic of [mathematical] analysis is to lead us by the best, the simplest, and the shortest method. This analysis is not one science separated from all others. It belongs to them all —it is their true method, their soul. I will call this analysis metaphysics, provided you do not confuse it with the first science of Aristotle. Roger Mathew Grant [email protected] Assistant Professor and Fellow, Society of Fellows, University of Michigan