Galileo/Talk

When Galileo was defending the copernican model, it was not scientifically superior to the Ptolemaic system. Copernicus still tried to use circular orbits, and as they failed, had to use epicycles and other resources of Ptolemaic kinematics. Only after Kepler's work (that was largely ignored by Galilei) was incorporated in the theory, and Newton's law of gravity gave a sound physical basis to the whole system, was the heliocentric model undoubtedly superior.

Also, despite what is said, the Church did not approve the Ptolemaic system as real. It simply stated that both were simply devices to predict positions. It was Galileo who tried to force an acceptance of the Corpernican system as "real"

Wasn't the church was in definite favor of a geocentric universe, though? At least, there were many religious arguments put forth for it, and Copernicus undoubtedly published posthumously for some reason or another. Also the church had just finished some council or another where they decided there absolute and final stance on all sorts of issues, which I vaguely recall Galileo was opposing somehow...maybe the non-Aristotelian physics. In any case, I agree that the church was being fairly nice until Galileo got out of hand. --Josh Grosse

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Even in its early form, though, the Compernican system was clearly superior to Ptolemy in that the model of a tilted Earth rotating around the sun explained the oddly-inclined motion of sunspots in a simple way that Ptolemy could not, for example. Yes, Copernicus got a few things wrong like circular orbits, and Galileo himself was mistaken about his threory of tides being caused directly by the rotation of the Earth, but overall, his threories were still far superior to Ptolemy.

The church might not have accepted Ptolemy as "real" (and I don't think my text claims that), but at no point did Galileo ever claim that Copernicus' model was real either. The churuch's main concern was with scripture that claimed the Earth was stationary. The generally-accepted Ptolemaic system fit with that; the Copernican system (even in its early less-than perfect form) did not. Galileo pointed out that by _assuming_ a Copernican model, you could more easily calculate and predict certain things, but at no point in his life did he ever claim (at least publicly) that the system was "real"; he firmly backed away from such claims at every opportunity. De Revolutionibus itself is a masterpiece of weaseling and backpedaling.

Did Galileo claim the universe was heliocentric, though? I can't imagine why he wouldn't have - after all, he defied the church to publish material on it (assuming the Dialogues mention the topic), and it seems more likely that he would do so if he though it was genuinely valid.

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Actually the church claimed that in the book of Joshua when the text says that miraculously "the sun stood still" it implies that the sun rotates around the earth. This among other texts led the church to believe that be bible claimed that the Copernican theory was false, but it is now commonly understood that these texts were only intended to describe what the spectators saw, not to describe the natural processes behind the events, so the church now has no problem with the heliocentric position.

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Does anyone besides me feel that Galileo should be credited, even more so than Newton, for founding modern science by conducting experiments rather than relying on mere conjecture (as Aristotle did). Or was there someone before Galileo who not only relied on experiment, but realized that it was the only way to really learn anything about the world?--BlackGriffen

I think Francis Bacon came before Gallileo in that regard. --LDC