The trick is to stop thinking in terms like
something we can believe
and
accept it into their belief system
Ideal rational entities just assign probabilities to each possibility (using Occam's razor if nothing better suggests itself), and then update using Bayes theorem when they see evidence. They can then make action in light of these probabilities (trying to maximise some utility function). The points on your list all follow from trying to obey the laws of probability and utility maximisation. In the case of the earthquake there are a variety of explanations, some of them are fairly likely ("nearby avalanche", "large creatures (e.g. George) moving about", etc. ), some are fairly unlikely ("plate tectonics", "attack by a technologically advanced tribe") and some are very unlikely ("God did it", "random movement due to thermal vibrations"). As they gain more evidence their beliefs will change. But they never have to accept one belief or another, they can quite happily maintain their probability distribution and be honest about their ignorance.
Also note that their probability distribution can be useful even if it is spread across many possibilities (i.e. if they are very ignorant). For example, if all of the most likely hypotheses predict recurrent but infrequent earthquakes, then they can be confident in this prediction even though they don't know which of those hypotheses is correct.
Topic: When does something stop being a “useful theory” and become something we can believe?
[Preface - Hi! This is essentially my first time posting here. If I did something wrong, let me know. I've read about 1/3-1/2 of the major sequences, but feel free to reference a specific article if you think it helps answer the question]
We see something in the world that appears mysterious to us, and we come up with an idea (“idea X”) that explains it. For X to be fact, it should:
1) be internally consistent with itself, as well as with all its implications. i.e. if X, then Y, and if Y, then Z. If we know Z to be obviously false, then we know X must be false.
2) be externally consistent with reality as we know it. We can’t find something in reality that makes X clearly unture.
3) Explain things we have already observed (that’s why we’ve come up with idea X in the first place)
4) preferably, “make beliefs pay rent” – we should be able to use X to make predictions of the future, otherwise it doesn’t hold much value.
(By the way, if you disagree with 4 let me know, I’d love to hear your take. I’m not being sarcastic. Truth is still truth, even if there isn't any utility in believing it.)
So, lets say we’ve got a Generic Tribe of Primitive Peoples. They experience an earthquake. It’s the first earthquake in 50 years. They ask Wise Old Jim what all the commotion was. Jim, who is 57 and the only one who’s seen one before, thinks for a while, then says, “I’m not sure, but here’s one possibility: That’s George the Giant, who lives on the other side of the mountains, rolling over in his sleep. He does that occasionally.”
Now, this story about George is:
1) internally consistent (it makes sense that giants would sleep for a long time, and roll over occasionally.)
2) externally consistent (George is on the other side of the mountains, which is mysterious uncharted territory. He’s heavy enough to rumble the earth all the way over here. No-one can think of anything they’ve seen to make his existence unlikely.)
3) explains the earthquake
4) It lets us know that the world isn’t ending, that nothing major has changed, and that this is a natural occurrence which will probably happen again years later. All of which are true.
[In this scenario, there is not in-reality a giant on the other side of the mountains, but they have no way of crossing the mountains to do the obvious empirical test to confirm it.]
So… what are these folk doing wrong? Is this theory supported and useful enough for them to accept it into their belief system? Should they develop some kind of falsifiable hypothesis? If so, what?
Even if *you* can think of a solid test, what if the whole tribe tried to think of a test, but couldn't think of a good one that would confirm or reject the theory? Should they accept this theory or not?