Music and the Making of Modern Science

94 Chapter 6

which are several well known to him from musical theory, such as^43 ,^25681. Perhaps there is

no connection in his mind between these identical results for different musical and

mechanical problems, but they remind us (as may also have struck him) that both sets of

questions play out on the same mathematical terrain, between pure number and sensuous

reality.^21 In this letter, as in his work as a whole, musical theory had set the mathematical-

empirical stage on which the new natural philosophy would perform. In his final lines,

Descartes mentions a new problem straddling mechanics and music, which Mersenne had

posed: what are the motions of a lute string when plucked?

Descartes enlarges the scope of such investigations in his next letter (November 13,

1629): “ In place of explaining only one phenomenon, I have resolved to explain all the

phenomena of nature, that is to say, all of physics. ”^22 Questions, first about music, then

pendulums and parhelia, have mushroomed into a project to understand “ all the phenomena

of nature ” as mathematical physics, a vast synoptic enterprise. Descartes returns to

the pendulum in a vacuum and gives a more detailed account in which again the music-

theoretic numbers 2, 4, 8, 9, 12, 16 figure prominently. He then returns to the problem of

Figure 6.3

Parhelia (mock suns or sundogs) in Fargo, North Dakota, 2009.