I find it highly unlikely that a superintelligence would care to create a medieval simulation with tons of suffering

You are asserting a false duality. Either many-worlds, OR a collapse postulate. You use evidence AGAINST a collapse as evidence FOR many worlds, which is very weak evidence. Here is a third alternative- the wavefunction is not real- merely a mathematical formalism used to calculate probability distributions (this map doesn't have to be the territory). Here is a fourth- collapse is an approximation to a small, non-linear self-coupling in the equation that governs time evolution. Here is a fifth- evolution is governed by both the advanced and retarded Green function solution to the Schroedinger equation, and what appears to be collapse is a sort of beat-resonance between the two. Here is a sixth- there are(non-local) degrees of freedom apart from the wavefunction and 'collapse' occurs because our existing theory is confused about what devices actually measure. I could keep going.

Every one of the above has a huge advantage over many worlds- there is positive evidence to update in their favor. Because they accurately reproduce most of quantum mechanics, all that evidence that we can use to push us to "quantum mechanics is probably right" CAN lead us to any of the above theories.

Many worlds does NOT have Born probabilities, and so IT DOES NOT MAKE PREDICTIONS. No one knows how to use many worlds to do anything at all. So you are doing a very weird sort of Bayesian process- you use Copenhagen or one of the above theories' predictions to update your belief to "quantum mechanics is probably right." Now starting from this new belief, you use other facts to update to "many worlds is probably right." Unfortunately, you didn't notice that in switching to many worlds, all of that evidence that pointed to quantum mechanics is gone.

If you start from an agnostic prior, many world's has no predictions to push you in the direction of "this is the right theory."

Some weird results in that poll... 42% believe Copenhagen is the correct interpretation, but only 30% believe that Bohr's view of QM is correct or will ultimately turn out to be correct. So at least 12% don't think Copenhagen is Bohr's view, which leaves me wondering what they think it is. The natural assumption would be that they think of Copenhagen as an objective collapse theory (in contrast to Bohr's instrumentalism), but that can't be right because "objective collapse" was a separate and much less popular answer. I do notice, though, that the percentages on the interpretation question add up to more than 100, so perhaps some (or all) of the people who chose "objective collapse" also chose "Copenhagen".

Also surprised that while 18% of respondents chose Everett, only 9% believe that the randomness in quantum mechanics is neither fundamental nor irreducible. What the what?

We understand why the evolution of classical systems is governed by classical probabilities---just churn through the quantum mechanics. Decoherence is very simple...

Decoherence isn't actually enough to show why quantum amplitudes show up as classical probabilities- if it were the Born-amplitude problem in many worlds would be solved. You need assumptions to turn "the wavefunction looks like this" into "the wavefunction looks like this so we expect to see result A with probability whatever." Decoherence tells us off-diagonal elements in the density matrix aren't likely to survive interaction with a larger system- thats not enough to connect to experimental values.

You jump straight from decoherence to "experiencing branches" without defining what you mean by "branch. "

this is enough for the vast majority of physicists to reject MWI

Cite, please.

we don't know whether worlds branch or diverge

It's a field. There's no meaningful distinction here.

Tips: figure out if MWI is correct before you start worrying about these things. The existential crisis that can be brought on by thoughts surrounding QTI and QTorment can induce suicide and other bizarre behaviour. This is the reason that Jacques Mallah wrote a paper on the fallacy of quantum immortality, because he estimates the risk is too high that people will start dying over this interpretation.

Now as Mitchell Porter says, MWI got some problems, mainly the Born Rule and Preferred Basis, aswell as problems with having wavefunction realism in configuration space/relativity (prompting proponents of MWI such as Wallace to postulate Space-Time state realism) this is enough for the vast majority of physicists to reject MWI, even some of the early supporters like Weinberg has turned his back on the hypothesis.

But even if you do believe Many Worlds is true, you have to factor in another thing: we don't know whether worlds branch or diverge. Alastair Wilson and Simon Saunders have written about this, the math doesn't decide, so we can't know. It could be that once two outcomes can occur you "branch" into both worlds, or it could be that we are already on 2 separate, but identical worlds and when two outcomes occur, only one occur in the branch you are already isolated on. If this is the case, then quantum immortality is falsified 100% bcause you will forever remain on a single branch until the end of time... This also solves the "incoherence" problem with probability and lets us keep our episteomology.

Last, but not least I want to raise some criticism of Yudkowsky and Tegmark for introducing such ideas as fact, when there are severe problems facing it. It may have caused a lot of suicides from mentally unstable people, existential crisis and people who just thought quantum roulette would be a good way to get a better life, people who don't care about the overall measure. All because of something that is highly speculative with seemingly insoluble problems.

Note; The story I originally posted here was true and complete. However the details detract from the main point of the post, which was to indicate material support for life extension causes. Hence the edit.

Owing to a recent financial windfall, I now intend to travel the world working towards life extension. Im starting by pledging donations to the Brain Preservation Fund and the Kim Suozzi fund. Readers will also shortly see my name appearing on the donar list of the aforementioned funds.

I have a blog (link below) where I will soon be writing about my new life as I travel the world working towards life extension.

Happy journeys to us all and see you in the future!

My blog is here: http://zarzuelazen.com/wordpress/

Yes, there are objective facts. Whether a waveunction is made of 2 components or 1 is still not independent of your perspective. No, it's not necessarily nonsense. I am just claiming that the unsolved problems of stuff like "overlap" are not due to a lack of information about quantum mechanics, but due to a lack of information about very complicated things humans do. If it the difficulty of understanding how humans categorize things and revise categories gets attributed to basic quantum mechanics, then we may get some nonsense.

Ah, I see. "Metaphysics."

By which you mean "taking human morality and decision-making, which evolved in a classical world, and figuring out what decisions you should make in a quantum universe."

Would you agree that overlap vs. non-overlap cannot be answered without looking inside humans, and in fact has little to do with the universe apart from a few postulates of quantum mechanics? For some reason I thought we were talking about the universe.

Anyhow, I think Shane Legg had a nice paper on porting utility functions, though of course humans are inconsistent and you immediately run into problems of how to idealize them. The basic idea being that you split up changes into "new things to care about" and "new ways to express old things." Quantum suicide is probably the easiest thing to deal with via this method.

I understand what you are saying, which I think my last post showed quite clearly

Maybe you're just used to talking with people who are better at interpreting you, or people who are more similar to you. Clearly understandable to people you talk with every day isn't always clearly understandable to me, as we've seen.

What you are saying really amounts to saying that "realism and solipsism are the same", because we cannot really distinguish either through science, all we can do is use logic and metaphysical "reasoning".

Could you explain this? Is this a metaphor, or are have you interpreted my statements about vectors to actually bear on realism vs. solipsism? Perhaps we have been talking about two different things.

Obviously both overlap and non-overlap cannot be true, they are ontologically different

Ah. See, this is the sort of thing I was trying to illustrate with the example of the diagonal line. A line being made of one component is ontologically different from a line being made of two components. Does this matter?

What happens if a one-componenter runs into a two-componenter? Do they argue? Does the first say "because of [insert convincing component-ist argument here], it's ONE component!" Are there valid component-ist arguments? How can the two-componenter respond?

I think it would go more like this: the first one says "hey, if you describe lines in terms of plus and minus diagonals, this one is clearly just a plus diagonal, so why say it has two components?" And the second says "Oh, huh, you're right. But there are lots of horizontal and vertical lines out there, so two-components is more useful." And the first says "yeah, that makes sense, unless you were building a ramp or something." "Well then, cheerio." "Toodles."

The reason this was so anticlimactic is because each participant could frame their ontology in a universal language (vectors!), and the ontologies were lossless transformations of each other - in this case the transformation was as simple as tilting your head. This clarity of the situation leaves no room for appeals to componentism. Arguments are for when both people are uncertain. When people know what's going on, there's simply a difference.

Have you read any of the papers that outline this? Alastair Wilson have written several: http://www.alastairwilson.org/

Could you point me to an example? Similar to how we are potentially talking about two different things, Alastair Wilson seemed to be talking about something other than physics in the papers I skimmed. The phrase "the most appropriate metaphysics to underwrite the semantics renders Everettian quantum mechanics a theory of non-overlapping worlds" exemplifies this for me.