Re: Decker's new book
Posted: 14 Jan 2014, 09:36
Ross wrote,
Copernicus hoped, correctly, that it required no special technology or new mathematics to refute Ptolemy. That's why he combed the ancient literature for clues. For example, he found a key mathematical device, the "Tusi couple", in Proclus's commentary on Euclid. And it wasn't that the heliocentric model was simpler: spherical geometry as developed in ancient times was not simple, and Copernicus had more epicycles than Ptolemy. Ptolemy was simply wrong, refuted by observations easy to make if one was careful. The hard part was knowing the geometry that would tell you what observations to make and their significance. It is true that defenders of Copernicus said it was merely a simpler mathematical model, with no claims to real existence. But if you look at the work itself, that is not what he says, nor does the mathematics plus the observations imply it. Ptolemy's model predicted impossible things, Copernicus cogently argued.
It took Kepler and Newton, of course, to complete Copernicus. Newton, unlike Galileo, had no objection to occult forces permeating the universe. He had translated the Emerald Tablet and earlier in his life done alchemical experiments. His theory of universal attraction is simply part of the world-view of the Asclepius, which teaches the power of love not only toward God but of bodies toward one another (Copenhaver p. 79):
It seems to me that Copernicus probably mainly reproduced what Aristarchus (c. 310 – c. 230 BC) had done, in a lost work of which enough was cited by Archimedes in the so-called "sand-reckoner" (http://en.wikipedia.org/wiki/The_Sand_Reckoner) to give him enough to go on. Aristarchus is mentioned by Copernicus in one draft of his work (http://en.wikipedia.org/wiki/Heliocentrism). What is extant from Aristarchus suggests a complete system, although the mathematics probably wasn't as advanced as it could have been in Roman times. The "rotating earth" hypothesis had already been proposed by Heraclides of Pontus (4th century BCE), as well as Venus and Mercury revolving around the sun; these ideas might have been held earlier by the Egyptians, if Macrobius is to be trusted. The "rotating earth" theory is mentioned in Cicero and pseudo-Plutarch, both cited by Copernicus. One or two Muslim astronomers also held that the earth rotated, per Wikipedia. Others developed the mathematics but did not take it to its logical conclusion, perhaps for religious reasons. For one of Aristarchus's followers, Seleucus, one argument for heliocentrism, according to Wikipedia, might have been mutual attraction of large masses, as shown by the tides in relation to the moon. That is an approach even Galileo rejected.If any Muslim astronomers had developed a heliocentric theory, however rudimentary, or had a rotating Earth as part of that explanation, I have no doubt that researchers into the history of astronomy would have found them and pointed them out. They love this kind of thing, and every historian of science knows the value of Arabic translations of classical sources.
Copernicus seems to have been the first person to develop these ideas into a system.
Copernicus hoped, correctly, that it required no special technology or new mathematics to refute Ptolemy. That's why he combed the ancient literature for clues. For example, he found a key mathematical device, the "Tusi couple", in Proclus's commentary on Euclid. And it wasn't that the heliocentric model was simpler: spherical geometry as developed in ancient times was not simple, and Copernicus had more epicycles than Ptolemy. Ptolemy was simply wrong, refuted by observations easy to make if one was careful. The hard part was knowing the geometry that would tell you what observations to make and their significance. It is true that defenders of Copernicus said it was merely a simpler mathematical model, with no claims to real existence. But if you look at the work itself, that is not what he says, nor does the mathematics plus the observations imply it. Ptolemy's model predicted impossible things, Copernicus cogently argued.
It took Kepler and Newton, of course, to complete Copernicus. Newton, unlike Galileo, had no objection to occult forces permeating the universe. He had translated the Emerald Tablet and earlier in his life done alchemical experiments. His theory of universal attraction is simply part of the world-view of the Asclepius, which teaches the power of love not only toward God but of bodies toward one another (Copenhaver p. 79):
But even Newton did not go as far as to espouse that this mutual attraction actually accomplished the promiscuous but fertilizing union of everything with everything else, producing something new in the process which is then exchanged, described on the model of sexual intercourse:Grasp this in your mind as truer and plainer than anything else: that god, this master of the whole of nature, devised and granted to all things this mystery of procreation unto eternity, in which arose the greatest affection, pleasure, gaiety, desire and love divine.
For the modern scientific correlate to that, we had to wait for quantum mechanics, which teaches "exchange of virtual gravitons" (http://en.wikipedia.org/wiki/History_of ... nal_theory), gravitons being the modern version of the Asclepius's occult "issue" exchanged in intercourse among bodies. The result is the phenomenon we call gravity, and perhaps the universe of curved space-time itself....take note of that final moment to which we come after constant rubbing when each of the two natures pours its issue into the other and one hungrily snatches <love> from the other and buries it deeper...