Moving the Immovable 53
composed. But the reverse channel of influence is also possible: the teenaged Galileo may
have learned from other sources about Copernicus ’ s idea and brought it to his father, who
might have also had some earlier discussions with Zarlino on this matter. Though it is
beguiling to think of the intrepid teenager initiating his father into the new astronomy that
would lead to so much controversy and danger for himself, no extant evidence shows how
Galileo first learned about heliocentrism.
Evidence does emerge in Galileo ’ s early notebooks, dating from around 1590 (but pos-
sibly as far back as 1584), whose section on the heavens is closely copied after a 1581
work by Christopher Clavius, the eminent Jesuit astronomer.^36 When he comes to “ the
order of the heavenly orbs, ” Galileo (citing Clavius) begins with Aristarchus and Coper-
nicus, though the ensuing text amasses a preponderance of evidence against the Copernican
view.^37 Here, it is hard to judge how far Galileo is merely copying the received view,
showing his familiarity with it in order to advance his nascent academic career, or how
far he himself believes the prevalent view of geocentrism presented by Clavius. At the
very least, Galileo was well aware of Copernicus (and of the controversy surrounding him)
by about 1590.
In any event, the evidence presented above supports Vincenzo ’ s musical interpretation
of heliocentrism, with the implication that, for him, music illuminated and underwrote a
crucial astronomical innovation. As for his famous son, Galileo ’ s arguments for heliocen-
trism often turn to the same musical terminology and categories that we noted in Coper-
nicus, Praetorius, and Gilbert. For instance, in his “ Considerations on the Copernican
Opinion ” (1615), Galileo describes how,encouraged by the authority of so many great men, [Copernicus] examined the motion of the earth
and the stability of the sun. Without their encouragement and authority, by himself either he would
not have conceived the idea, or he would have considered it a very great absurdity and paradox, as
he confesses to have considered it at first. But then, through long sense observations, favorable
results, and very firm demonstrations, he found it so consonant with the harmony of the world that
he became completely certain of its truth. Hence this position is not introduced to satisfy the pure
astronomer, but to satisfy the necessity of nature. ... Who does not know that there is a most agree-
able harmony among all truths of nature, and a most sharp dissonance between false positions and
true effects?^38Here, the general language of harmony is further sharpened by specific musical distinctions
between consonance and dissonance, which Galileo introduces as a higher criterion rising
above the considerations of “ pure astronomy, ” which by itself never seems to have inter-
ested him greatly. His language remains consistent in his “ Reply to Ingoli ” (1624) even
as he turns to the more difficult issue with which we began, how the seemingly immovable
Earth could possibly be movable: “ Now if the nature of the earth is very similar to that of
moving bodies, and the essence of the sun very different, will it not be much more prob-
able (other things being equal) that the earth rather than the sun imitates with motion its
other six consorts? Add to this another no less notable harmony, which is that in the