The problems with this scenario is that it is at best incomplete as given, and the missing information is highly relevant.

Once upon a time the countries of Alpago and Byzantine had a war. Alpago was mostly undamaged during this war. Byzantine was severely damaged by this war, although they have caught up in some metrics such as education, their economy is still somewhat weaker. Alpago was the clear aggressor, and now, fifty years later, everyone who is reasonable now acknowledges that Alpago was in the wrong.

This is not the way things generally play out. Normally, after this kind of war everyone (at least outside Byzantine) acknowledges that Alpago was in the right (regardless of what an "objective" reading would suggest). While this is not always the case, your scenario failed to specify the reason.

Possible reasons:

1) While the Alpagoans were better at warfare, the Byzantines are better at education and culture and thus their version of history won out. In this case expect a lot of Alpagoans to present themselves as Byzantines.

2) Subsequently a stronger third power sided with the Byzantines and defeated the Alpagoans, without doing as much damage to them as the Alpagoans had done to Byzantine.

3) Following the war there was a revolution in Alpago and the new ruling class want's to portray their predecessors as warmongers to justify their revolution.

4) The Alpagoans are an extremely unusually fair minded people.

By comparison, it seems like it would be much easier for algorithms to assess people's IQ

Look at the general social reaction to the existence of IQ tests. A large part of it consists of dogmatic denial that IQ even exists.

How widely held, and how well supported, is the theory that the Roman empire failed because of overregulation and overtaxation? It's not a claim I've heard before, but I am about as far from being an expert in late Roman history as it is possible to be. In particular, how widely accepted is this theory outside circles in which everything is blamed on overregulation and overtaxation?

Overtaxation is a standard reason given for the fall of the Roman Empire, and I'm surprised you haven't heard of that before. I've never heard of overregulation being a reason; I've never looked into the Roman regulatory state, and have no idea how burdensome it was, or even if it substantively existed.

Terrorists are a rounding error. Sure, some day they'll take out a city with a nuke but in history cities have been wiped out many many times without taking their parent civilization with them.

In response to the Quora question "What are some important, but uncomfortable truths that many people learn when transitioning into adulthood?"

1. Every person is responsible for their own happiness -- not their parents, not their boss, not their spouse, not their friends, not their government, not their deity.

2. One day we will all die, and 999 out of 1,000 people will be remembered by nobody on earth within a hundred years of that date.

3. Practically all of the best opportunities (in business, in romance, etc) are only offered to people who already have more than they need.

4. The idea that you will be happy after you make X amount of dollars is almost certainly an illusion.

5. The idea that you will be happy after you meet [some amazing person] is almost certainly an illusion.

6. For most people, death is pretty messy and uncomfortable.

7. When you don't possess leverage (go look up "BATNA"), people will take advantage of you, whether they mean to or not.

8. Almost everybody is making it up as they go along. Also, many (most?) people are incompetent at their jobs.

9. When talking about their background and accomplishments, almost everybody is continually overstating their abilities, impact, relevance, and contributions.

10. Physical beauty decays.

11. Compared to others, certain ethnicities and races (and genders, and sexual orientations, and so on) are just plain royally f*cked from the day they're born.

12. Bad things constantly happen to good people. Good things constantly happen to bad people.

13. Very few people will ever give you 100% candid, honest feedback.

14. People are constantly making enormous life decisions (marriage, children, etc) for all of the wrong reasons.

15. Certain people -- some of whom are in positions of enormous power -- just do not give a damn about other human beings. A certain head of state in Syria comes to mind.

16. Often, the most important and consequential moments of our lives (chance encounter, fatal car accident, etc) happen completely at random and seemingly for no good reason.

17. Your sense of habitating a fully integrated reality is an illusion, and a privilege. Take the wrong drug, suffer a head injury, or somehow trigger a latent psychotic condition like schizophrenia -- and your grip on reality can be severed in an instant. Forever.

From Patrick Mathieson

When I said these things "grew out of the Western intellectual tradition" I did not mean to suggest that the steam engine had been invented by an academic. In fact, neither the steam engine nor the automobile was invented in a vacuum; whether or not the inventors of these things (or the people who first successfully mass-produced them) had university degrees is not the issue. Developing steam engines, internal combustion engines, electric generators and motors, vacuum tubes and semiconductors, and many of the other things that have driven the technology boom over the past couple of hundred years required scientific knowledge, and the modern scientific method was a development of the Western analytical mindset.

Worst case is IMHO that a new person will be created in an old and damaged body.

The existence of that low prior is the proof that it's very likely false

I think you're trying to double-dip :-) The prior itself is a probability (or a set of probabilities). A "low prior" means that something is unlikely -- directly. It does not offer proof that it's unlikely, it just straight out states it is unlikely.

And there doesn't seem to be any reason to talk about priors, anyway. It's not like at any moment we expect a new chunk of information and will have to update our beliefs. I think it's simpler to just talk about available evidence.

As a preface let me say that I basically agree with the thrust of your arguments. I am not a Christian, afer all. However I don't consider them as anything close to a "proof" -- they look weaker to me than to you.

makes supernatural claims; that is, claims which are by definition counter to all previous observations

That is not so. Supernatural claims do not run "counter" to previous observations, they just say that certain beings/things/actions are not constrainted by laws of nature. Wright brothers' airplane was not "counter" to all previous observations of transportation devices with an engine. Recall Clarke's Third Law.

Not to mention that "all previous observations" include a lot of claims of miracles :-)

its core claims (and future predictions) are similar to many sets of (mutually contradictory) claims made by many other religions

Yep. But there is a conventional explanation for that (I do not imply that I believe it): different traditions take different views of the same underlying divinity, but find themselves in the position of the nine blind men and the elephant.

This point will also need to explain why large civilizations (e.g. China) did NOT develop anything which looks like monotheism.

the average probability of any specific branch of Christianity would still be low

That's a wrong way to look at it. Imagine that you have an underlying phenomenon which you cannot observe directly. You can only take indirect, noisy measurements. Different people take different sets of measurements, they are not the same and none of them are "true". However this does not mean that the underlying phenomenon does not exist. It only means that information available to you is indirect and noisy.

it's likely that all sects' beliefs had human causes

See above -- different people might well have human reasons to prefer this particular set of measurements or that particular set of measurements. Still does NOT mean there's nothing underlying them.

it's because many people are Christians

Well, and why is that? Why is Christianity a huge world religion? It started with a small band of persecuted Jews, why did it spread so?

Very little published academic literature exists on the consequences of divestment.

This is because most people who study finance would put a very high probability on the consequences being zero. If my college refuses to buy from a firm it hurts that firm a little, but if it refuses to buy stock in a firm it does that firm zero harm. The best evidence is that while firms frequently advertise to get people to buy their products, they almost never advertise to get people to buy their stock. The value of a firm's stock is determined by what the big players in the market think are the long-term fundamentals of this stock.

Consider the following proposition: For each existing religion, one can easily set out evidence of its wrongness that would (1) be very convincing to the majority of people who are not already positively disposed towards that religion and (2) be good reasoning in the abstract; if we combine these, we get a strong argument that no existing religion is close to the truth, but this argument will not convince most people because most people are adherents of some religion or other, and it is extremely difficult for adherents of any religion to appreciate the strength of arguments against that religion.

It seems to me that that proposition may very well be true, and that if it is true then it's correct (aside from the fact that "proofs" is too ambitious a word) to say both that it's difficult to convince people that all existing religions are wrong, and that the proofs of that fact are not hard to verify.