Take all the metaphysical models of the universe that any human ever considers.
Say there are n number of mutually-incompatible ones. I don't have a good definition of this, so our estimates will vary by orders of magnitude.
Start with 1:1 odds, or a 50% chance that one of them is correct, and a 50% chance that none were correct.
0.5/n is the prior for a given individual metaphysical model.
You might have opinions about "50%". Maybe you think humans are actually way less likely than that to ever think of the "right" one. Maybe you think we're almost guaranteed to, for some reason. I started with a very general, unimposing prior of 1:1 odds. We can generalize this to p/n, for whatever you think p is.
How big is n? I don't know but I ran a Twitter poll asking people to pick a rough order of magnitude. I would like a number. It's easy to lie with numbers, but it's even easier to lie without them.
Updates away from the base rate can be made based on the complexity of the idea. This mechanism is very general, and it should apply even in this domain to some extent. Some religions are crazy complicated, so probability mass should be gouged from those. Though, estimating "complexity" is going to be very hard. The lady down the road is a witch, she made the universe. Still, do we have zero information about such complexity comparisons? I doubt that.
I have seen smart people say there is no way to assign probabilities to metaphysical ideas. They then express opinions about many worlds interpretation, the simulation argument, and others. They'll do it with even less informative, more nebulous terms than a probability. Such as "I am skeptical", or "seems really likely". As a forecaster I have also seen some wildly overconfident claims made by some smart people. Many orders of magnitude above a cloud of reasonable base rate estimates. I know they don't have that much information and aren't calibrated.
I thought it would help to give a simple base rate template. So here is one.
Cool idea.
Any model we actually spend time talking about is going to be vastly above the base rate, though. Because most human-considered models are very nonsensical/unlikely.
I don't think that solves the problem though. There are a lot of people, and many of them believe very unlikely models. Any model we (lesswrong-ish) people spend time discussing is going to be vastly more likely than a randomly selected human-thought-about model. I realise this is getting close to reference class tennis, sorry.
1Jotto999
I had little hope of solving much in this domain! But a base rate that is way off is still useful to me for some discussions. What you're pointing to might offer some way to eliminate a lot of irrelevant n, or gouge probability away from them. So with respect to discussions within smart circles, maybe the base rate ends up being much higher than 1/5million. Maybe it's more like 1/10,000, or even higher. I'm not a stickler, I'd take 1/1,000, if it lets certain individuals in these circles realize they have updated upward on a specific metaphysical idea way more strongly than they could reasonably. That it's an obvious overconfidence to have updated all the way to 50% chance on a specific one that happens to be popular in smart circles at the time.
Take all the metaphysical models of the universe that any human ever considers.
Say there are n number of mutually-incompatible ones. I don't have a good definition of this, so our estimates will vary by orders of magnitude.
Start with 1:1 odds, or a 50% chance that one of them is correct, and a 50% chance that none were correct.
0.5/n is the prior for a given individual metaphysical model.
You might have opinions about "50%". Maybe you think humans are actually way less likely than that to ever think of the "right" one. Maybe you think we're almost guaranteed to, for some reason. I started with a very general, unimposing prior of 1:1 odds. We can generalize this to p/n, for whatever you think p is.
How big is n? I don't know but I ran a Twitter poll asking people to pick a rough order of magnitude. I would like a number. It's easy to lie with numbers, but it's even easier to lie without them.
Updates away from the base rate can be made based on the complexity of the idea. This mechanism is very general, and it should apply even in this domain to some extent. Some religions are crazy complicated, so probability mass should be gouged from those. Though, estimating "complexity" is going to be very hard. The lady down the road is a witch, she made the universe. Still, do we have zero information about such complexity comparisons? I doubt that.
I have seen smart people say there is no way to assign probabilities to metaphysical ideas. They then express opinions about many worlds interpretation, the simulation argument, and others. They'll do it with even less informative, more nebulous terms than a probability. Such as "I am skeptical", or "seems really likely". As a forecaster I have also seen some wildly overconfident claims made by some smart people. Many orders of magnitude above a cloud of reasonable base rate estimates. I know they don't have that much information and aren't calibrated.
I thought it would help to give a simple base rate template. So here is one.