In the beginning of Galileo's Dialogue Concerning the Two Chief World Systems, one of the characters, Salviati, states: "Yesterday we resolved to meet today and discuss
as clearly
and in as much detail as possible the character and the efficacy of
those
laws of nature which up to the present have been put forth by the
partisans
of the Aristotelian and Ptolemaic position on the one hand, and by the
followers of the Copernican system on the other. Since Copernicus places
the earth among the movable heavenly bodies, making it a globe like a
planet,
we may well begin our discussion by examining the Peripatetic steps in
arguing the impossibility of that hypothesis; what they are, and how
great
is their force and effect. For this it is necessary to introduce into
nature
two substances which differ essentially. These are the celestial and
the
elemental, the former being invariant and eternal the latter,
temporary
and destructible. This argument Aristotle treats in his book De
Caelo,
introducing it with some discourses dependent upon certain general
assumptions,
and afterwards confirming it by experiments and specific
demonstrations.
Following the same method, I shall first propound, and then freely
speak
my opinion, submitting myself to your criticisms -- particularly those
of Simplicio, that stout champion and defender of Aristotelian
doctrine."
If I'm not mistaken, this and the bolder statements that follow are part of the reason Galileo was tried. It looks long-winded but the concise language Galileo (or Galileo's translator Stillman Drake) uses makes his initial point of criticism clear. I'm not sure I follow his argument about the celestial vs. the elemental maybe because of lack of knowledge of Aristotle. Is there a connection I'm missing between Aristotle and Copernicus that he's making?
It's great to see people reading Galileo's dialogues. They're not literary masterpieces, precisely, but they are fascinating. The choice of dialogue form may have been, in part, an attempt to avoid official censure, since in a philosophical dialogue each side makes its best objective case and the author need not overtly affirm either one. Unfortunately the church officials missed that nuance, but I've heard that they apologized a couple years ago (just a few centuries too late for Galileo).
ReplyDeleteTo clarify the argument: Aristotle holds the 'elemental' world -- where we live -- to be different in kind from the eternal, changeless, 'celestial' sphere. Copernicus' revolution is to treat the earth (including ourselves) as part of the celestial process rather than separate from it, and the heavens are ultimately no more changeless than are we.
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