The doctrine's founding problem is its charm: if the heavens sound, why is the world silent? The Pythagorean reasoning ran forward confidently enough. Bodies so vast, moving so fast, must make sound; their speeds stand in ratios, as the hammers and strings do whose ratios Pythagoras was credited with discovering; therefore the sound is concordant, a cosmic harmony.
To the missing perception they gave the answer Aristotle reports: the sound is with us from birth, and since hearing exists only against silence, a noise never interrupted is never noticed, as smiths cease to hear their own forge. Aristotle records the theory with respect, elegantly and brilliantly stated, he allows, and then dismantles it as physics: so great a sound should shatter rocks, not merely elude notice, and in his cosmology the spheres do not move through a medium but carry their contents frictionlessly, so nothing rubs, and nothing sounds. The rejection did the doctrine no lasting harm, because its appeal was never acoustic. Plato had already given the deeper version in the myth of Er, a siren on each whorl singing one note, the eight together one harmony, with the Fates singing past, present and future above them: the music as the audible face of cosmic order and cosmic time. Cicero's Dream of Scipio added the moral: souls attuned to that order return to it. The unheard music became a figure for everything real but imperceptible, order, proportion, providence, and silence, reframed as a hearing failure of ours rather than a muteness of the world's, was the doctrine's masterstroke.