What does a field of study do if there are several competing theories?
- The Natural Sciences: I would like to think that the truth wins out... eventually. There may be struggles and politics and whatnot but in the very end experiments are performed and the more predictive theory wins out (I know its more complicated then that.) There are some fields where it is hard to do experiments (e.g., String Theory). Others where the theory gives great explanatory power but might be hard to do direct experiments (Evolution). Those cases may be hard to deal with, but they manage. Does String Theory have great explanatory power?
- Mathematics: Here the question is not WHAT IS TRUE since we can use proofs (Again, I know its more complicated than that) but WHAT IS WORTH STUDYING. Applied Math may still use the real world for a litmus test to some extend. More abstract kinds of math may be harder to test by looking at the real world. Do Large Cardinals exist? Is the Axiom of Determinacy true? Some people claim that they look for internal consistency and also intuitions. And some people live-and-let-live (you want to use AC, fine, I won't) (Again, I know its more complicated than that.)
- Astrology : What does a field do when its predictions are either vague or no better than chance? If there was a well designed experiment to test which theory has more predicative value then I suspect they would all be found wanting. (Then again, I'm a Sagittarius and we are known to be skeptical.) So what other criteria could they use? Internal Consistency and Intuition? Whichever one makes people feel better (some astrologers might claim that they are really psychologists, telling people what they want to hear to sooth them). Whichever sells more books? Makes more money? Is there some sort of aesthetics involved? I ask this nonrhetorically. (An idea for a scam: The old astrology doesn't work because they don't take into account relativistic effects on the planets. Use my Relativistic Astrology! For people who like what they believe in to have some buzz words from science thrown in!)