Ptolemy was a Greek in Roman Egypt in the 1st Century AD. He was one of the pre-eminent natural philosophers of the ancient world and he is a wonderful example of what science isn’t.
Ptolemy attempted to address one of the major scientific problems of the ancient world (and the pre-modern world as well), the retrograde motion of the planets. Simply put, although the stars move in a great circle in the sky and the sun and moon move in a steady circle through this stellar background, the planets, those great wanderers, would occasionally move backwards against the stars. This was very difficult to explain in an earth-centered universe and even more difficult to predict. Along with predicting solar eclipses, this was one of the main problems of pre-modern astronomy.
Ptolemy created a model of perfectly nested spheres with the earth at the center and all the bodies of astronomy radiating outward. You can see a simplified version of it here. He solved the problem of retrograde motion with “epicycles” smaller spheres within spheres which would sometimes make the always perfect circular motion appear to run backwards. But the perfect, spherical motion was always in the same diirection, always at the same speed and always and ever circular.
Why circular and uniform? Because Ptolemy knew that the universe was perfect and circular. In modern parlance, that was the paradigm within which he operated, one greatly developed by Aristotle centuries before.
The problem was that his predictions were often wrong. He would be a little early or a little late with a predicted eclipse or the start of Mars’ retrograde motion. Every time he made a mistake, he would tweak the model a bit and add another “epicycle” to his model, one more circle within a circle to make up for the last mistake, anticipating the still additional adjustments to be made again and again down through the centuries until someone finally realized we weren’t the center of the universe, and though it might be perfect, the universe or at least the planets, moved in ellipses, not circles.
The observations did not match the models, the predictions never accorded with the results. But he knew the answer and so his model just needed a bit more tweaking to finally approach the perfection of the universe. Ptolemy and his followers knew the answers because their entire philosophical system was tied up in them. Their “theory of everything” was Aristotelean in nature, but had been adopted by the Catholic Church and all of Europe by the time the Renaissance was kicking off. The assumptions of Aristotelean physics were tied into the Christian world view; the perfect circle, the finite universe, the geo-centric universe, the four plus one elements. All of these things were tied together with logic and theology so that by the time Copernicus and Galileo showed up, to challenge the music of the spheres was to challenge the truth of scripture.
Yeah, sure, but what has this got to do with Global Warming? Just Read On McDuff…
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