I'd like to suggest that we start with some definitions of what a good theory is supposed to be. I subscribe to the view that there are three metrics for estimating the "cash value" theory:

• Accuracy
  • The "cash value" of a scientific theory is quite obviously rooted in the practical utility of being able to predict future events, insofar as this gives us the ability to arrange things to our advantage. If it were not for this value, there wouldn't be any, in any intellectual enterprise.
  • This does not negate the value of being able to explain things after the fact (sometimes called "postdiction"). No hypothesis that can successfully predict future events would fail to "postdict" past events. And since the existing data are free, the first test of an hypothesis should always be whether or not it accurately explains the known data (i.e., would the hypothesis actually have predicted those data had they not already existed). If the hypothesis fails at that, any successful prediction is surely just coincidence.
• Scope
  • This is just a "cash value" multiplier. A single hypothesis that can accurately explain & predict 10 times more stuff is worth 10 times more, just as a universal wrench is worth more than an entire toolbox full of standard wrenches (assuming that it performs as well on each individual bolt).
• Simplicity
  • All other factors being the same, the simpler theory is just easier to use, so that's the one we'll consider to be "correct."

By using objective metrics such as these, we can get past the most common problem in pseudo-scientific thinking. A lot of people seem to think that if they can get people to believe what they're saying, then it's just as good as any other hypothesis out there. In other words, they think that hypotheses are social activities, which don't actually have to be about anything (except the people who are proposing the hypotheses). People who think this way will then engage in all kinds of tactics to bring people around to their way of seeing things. But there isn't any intrinsic merit to such an enterprise, and with objective metrics, we can easily see this. The value of science isn't that somebody won an argument — it's that we became better masters of our destinies.