Mersenne’s Universal Harmony 107
Trinity and the number three, descending into the created world as larger and larger
numbers come into view. Mersenne had deep theological disagreements with Fludd ’ s
pantheism: “ He mixes the Divinity with creatures, as if the latter had the divine essence
for their form. ... I do not believe that he wanted to corporealize the Divinity, and I attribute
it rather to his ignorance than to his malice that he considered creatures as nothing else
but God. ”^10
In the end, though, Mersenne judges Fludd more in terms of the empirical grounding
of his claim, finding “ no solidity in all this discourse [of Fludd ’ s] ” ; he is rather “ of the
opinion of Kepler, who contends that all the harmonies of Fludd and the Platonists are but
analogies and comparisons based only on imagination. ”^11 Mersenne dismisses Fludd ’ s
harmonies as arbitrary and ungrounded; he confronts them with what he considers proper
numerology from Plato and also uses the work of Regiomontanus (the greatest astronomer
in the century before Copernicus) to attack the details on which Fludd built his harmonies.
Mersenne emphasizes what he considers gross physical errors in Fludd ’ s argument, such
as a triangle of strings that “ can not produce the sounds of the musical scale, if they are
of equal thickness and tensions, ” as Fludd had supposed, which Mersenne corrects in his
diagram ( figure 7.2 ).
Fludd ’ s basic physical misunderstanding violates Mersenne ’ s deep commitment to the
facts of harmony, not just their language. After remarking in a conciliatory vein that “ it is
much easier to reproach others than to do better than they, ” Mersenne still concludes that
“ it is far better not to know this Harmony at all than to imagine it as something entirely
other than what it is, ” as Fludd had. “ False imaginations exercise indescribable tyranny
upon our spirits, from which our spirits can disengage themselves only with difficulty. ”^12
Thus, Mersenne feels compelled to exorcise Fludd ’ s false harmonies at the same time as
he embraces Kepler ’ s; both being heretics (one a pantheist, the other a Protestant), the
grounds of Mersenne ’ s choice remain musical, rather than theological.
Though himself orthodox, Mersenne ’ s passion for universal harmony led him to espouse
a teaching anathematized by his superiors. Far to the north of the Curia, from within the
proudly independent French church, Mersenne was able to advocate the Copernican cause
in ways not possible to Galileo, whom he attempted to befriend and defend.^13 But this was
only one facet of Mersenne ’ s amazingly diverse interests, which extended throughout the
whole realm of science and engineering. This got him into trouble during his first foray
abroad, to the Netherlands in 1628 – 29. Though himself without funds, he traveled at the
expense of his order and exhibited such curiosity about everything he saw that, near
Anvers, he was arrested as a spy and thrown into the tower overnight. On another occasion,
a suspicious soldier shot at him, though fortunately the weapon was not loaded.^14
During the height of the correspondence we examined in the last chapter, the Galileo
affair was just becoming known in France while Mersenne was immersed in the prepara-
tions for his largest work, Harmonie Universelle (1636 – 37). Throughout its fifteen hundred
pages, this book demonstrates many times over the centrality of music in his work on