There are some issues we need to get out of the way. I suppose “we” refers primarily to “me” but that is what it is. The way we see anything is by models of behavior. When you speak to me in ‘that way’, I interpret it in accordance with the model I have of your behavior in my head. That’s what being a human is all about, and in fact it is what all living things are about. A fish snaps at a fly even if that fly is just feathers with a hook in it because it approximates a model of reality preprogrammed in its head. Scientists also, therefore, see in phenomena what they want to see based on models they or their predecessors have developed of this type of phenomena. These models, like the memes that they are, do not just disappear into thin air. They are tenacious parasites in our brains. Changing a time-honored model (paradigm) is a painful process for all of us, scientists included; that difficulty is what ‘The Structure of Scientific Revolutions’ by Thomas Kuhn was written about. It is a necessary process in science, but not one that occurs without turmoil. Suspension of belief sufficient to understand another point of view has the negative side effect of leaving us vulnerable to wasting our valuable time or of being empathetic to dangerous conspiracies. No doubt for competitive advantage evolution has reduced this to a truly rare human quality. However negative the side effects might be, it is a necessary vulnerability if we are ever to approach a perception of reality ‘as it is’ and not just a temporarily ‘workable solution’.
A related topic is ‘theory-laden’ data; it is one with which we must grapple in cosmological investigations because the very concept of the central fact of cosmological redshift has by now been associated so strongly with recessional velocity that the two have come to be treated as virtually identical. It is as though the primary ‘fact’ of the universe were a big bang justified by ‘actual observations’ of expansion of the universe and the secondary fact of ‘dark matter’ justified by the gravitational force necessary to account for ‘fingers of god’. Like, how else could all this have come about? The metric for the unit-less quantity of redshift, that is in reality the observed facts behind all these models, has become velocity. And if one would argue with the accepted expansion of the universe or dark matter paradigm, one is forced to back out the presumption of recessional velocity as the cause of redshift from conflated observations before one can show what is predicted by the new paradigm. To do that one must not only suspend belief to understand the model one is attempting to replace, but one must be adept at using it to remove the now-unjustifiable assumptions that have become embedded in, and contaminated by, the data itself. It’s irritating, but that’s how it is.
Ultimately, of course, there must be valid criteria for accepting one model over another. Those criteria are the same capabilities one must employ to avoid falling for dangerous conspiracies:
1. Does it in fact predict the data it was introduced to account for? This is the primary criteria for any scientific model. If there is some aspect of the data that it does not account for, is there a sound logical reason why it would not in that case?
2. If it does, in fact, account for the data satisfactorily, does it make any sense at all? This is where intuition comes in as a selection criterion and admittedly intuition can be, and often has been, wrong. Does it involve a deus ex machina, i.e., does it depend on something for which there is no justification provided? Does it depend on some previously (or elsewhere) unobserved phenomena with inadequate justification for why it has not been observed? Is something created from nothing? Do marginally justified aspects occur at multiple stages of the model?
3. Is it logically consistent, i. e., if the assumptions are valid and sufficient data has been addressed, is it logical that the predicted behavior would result? Are there mathematical errors in the formulation?
4. Finally, and this involves both 2 and 3 above, is it the simplest possible explanation of the phenomena? This is called Occam’s razor, but Einstein’s expression for this concept was, “Would god have done it that way?” This eliminates Rube Goldberg type models — whatever your conception of god, he/she was no Rube Goldberg.