Ptolemy's system......genius or not?

[michelle...@gmail.com]

In lecture, we discussed how Ptolemy's system's was so great and how it worked so well. However, it was also said that it was also "a rather tortured accomodation of the evidence within a recognizable Aristotelian worldview". Not to be rude or dismiss Ptolemy's work, but making up rules about the universe so it fits your thesis isn't very genius to me. Someone please refine the significance of this system for me? 

[G. Randolph Mayes]

This is a very interesting question. I'd like to wait and see if anyone else has an answer to it before giving you mine.

[tosca...@gmail.com]

I think that this is what you have to do in order to make advancements in science... you have to think something up and then see if you can get it to fail. If it fails, then this is where you go back to examine your auxiliary hypotheses and modify. It's kind of like a "go big or go home" sort of mentality, I think. I used to do theater back in the day and my directors would always insist that it's better to go too far and come back than it is to start with nothing. 

I'm not a philosopher and technically, I'm not really a scientist yet. This is just my hypothesis about all of this.  

[G. Randolph Mayes]

You're right that making up any old rule that preserves a favored thesis isn't genius, it's dishonest and certainly unscientific. 

I think the best defense of Ptolemy here is (a) the theses he was defending weren't his pet theses, but core conceptual truths at the time. The perfectly circular and uniform motions of the planets, as well as the immobility of the earth were very deeply entrenched; and (b) the discovery of eccentrics and equant points was a remarkable feat of geometry. It's important to remember that they are actual discoveries. Before astronomers went about trying to preserve the Ptolemaic system in this way, nobody knew they existed. So discovering that they do exist gave them a reason for thinking this is what was really going on.

The mathematics of epicycles turns out to have been very important in its own right. It's just not a correct description of what is going on in the sky.