282 Chapter 18
systems that would populate Descartes ’ s infinite space. For a long time, the universality
of Newtonian law, general relativity, and quantum theory specified the overarching
harmony of all observed phenomena. But various zones of the universe may have utterly
different and unrelated local physical “ laws, ” as has emerged in the consideration of pos-
sible string theory models. Some have embraced this “ landscape ” of different, even diver-
gent or contradictory, universes within a larger “ multiverse ” ; others have insisted that
finally the universe must be a unity, with a single set of universal laws.^24 This choice
between competing antimusical and musical themes mirrors the contrast between the sonic
worlds of John Cage and Josquin des Prez. Randomness may finally rule, perhaps accord-
ing to an “ anthropic principle ” that explains our local laws as merely the coincidence that
in this region sentient observers happen to be physically possible. Others find this purely
contingent (even ad hoc) reasoning disturbingly incoherent and opportunistic. Yet harmony
emanating from a transcendent source seems unified to a troubling degree, requiring a
single universal pattern, such as Pythagoras heard in the smithy “ by the favor of a god. ”
Even Plato ’ s mighty demiurge did not create the eternal Forms but merely used them
as patterns, with some discretion.^25 Must cosmic harmony have a unique, essentially divine
source? Even those open to such ideas may worry about a single power capable of impos-
ing itself on the whole cosmos. Physics is on the verge of its own Darwinian turn: perhaps
each aspiring universe must struggle with its own inner tensions, as well as with the other
universes; arguably only a limited number might survive. Could that number be only one?
If not, do global principles limit or fix the number of universes within the multiverse? For
instance, consider the principles that constrain the formation of soap bubbles and whose
analogues might constrain universes considered as cosmic “ bubbles ” ( figure 18.5 ).^26 Gen-
eralized considerations of harmony and dissonance may be the decisive factors determin-
ing whether any given universe survives or indeed whether any incoherent assemblage of
unharmonized universes can endure. In the end, music may be the final and deepest —
perhaps the only — raison d ’ ê tre.
In the beginning, music provided the middle ground, the epistemic interface through
which natural philosophy could connect with mathematics, bridging the invisible realm of
number and visible phenomena.^27 In the sisterhood of the quadrivium, “ music ” meant the
dispassionate “ music of the spheres ” ( musica mundana ) rather than the expressive art of
moving the passions, both known since antiquity. Their intertwining histories would
require another volume.^28 In the examples considered in this book, that passion-laden
music informed the episodes surrounding the mathematical innovation of “ irrational
numbers, ” Kepler ’ s doleful song of the Earth, Euler ’ s “ modern ” mathematics of sadness.
But for the most part, the impassive, transcendent music of the spheres has remained the
touchstone of harmony even into the quantum period and beyond: for instance, Planck ’ s
critique of “ anthropomorphism ” and his quest for a truly “ natural ” tuning sought an
unchanging cosmic standard. To a striking extent, the project of natural philosophy,
modern as well as ancient, has remained faithful to the search for cosmic harmony