Can I ask a related question? Is there a physical model available that allows for immortality (eternally stable structure) in a cyclic model of the universe only (limited space with finite time between cycles)?

MWI and other parallel universe models seem to allow for suitable ways of replication and escape - but I never found anything related for a cyclic model. There is talk of surviving the Heat death (superconductor based computers) and Big Crunch/Big bang (using suitable black holes, etc..) - but there is one specific problem I haven't seen addressed: Particle decay.

If everything else works as planned and a future stable structure is created - in a cyclic model - Is there any way to prevent it from catastrophically desintegrating through particle decay (which is bound to happen in enough finite time)?

In the Least Convenient Possible World the stranger says "Hell no!"

Now what?

As hard as I try I cannot fathom the: "If it's untestable, anything is possible - if anything is possible, nothing is possible - nothing is the simplest and therefore best explanation" argument.

Everything requires a reason (the Existence of a reason or cause - if its comprehensible and testable is a separate question) The fundamental question always go back to "why and how Existence at all". Of course we cannot make direct measurements regarding the origin of Existence - but we can certanly base our hypothesis and theories on our acumulated knowledge and daily, testable physics. The corect logic would therefore be to extend all the known and proven constants into the unknown (through symetries, conservation of energy, ..) - not to allow there every single possibility, specially illogical ones,. Or to put it simply: Only when You eliminate the logical, can You turn to the illogical.

Nothing conclusive from our past and currenty physical knowledge proves, that Creatio Ex Nihilo is an actual phenomenon or even that it is physically/logically possible. Most importantly - there is not one single complete idea (that I know of) that explains the mechanism, of how absolute Nothingness (Non-Existence) can spring forth anything else but further "Non-Existence". I don't need to stress out that there is even less talk about why this Non-Existence would produce or could even allow for just one single universe. If anything - if Non-Existence could produce our universe it could (and must of have) produced many - if not all physicaly/logical universes - if not even more, illogical ones. Seems to me, that if You want to talk about true Creatio ex hinilo - You must support the notion of a max. large multiverse: An Ultimate Ensemble (which is the totally opposite view most people wan't to prefer Creatio Ex Nihilo for - Occam can be tricky sometimes).

Sure, there are theories that promote the idea of the Big Bang "from nothing", but there is always "something", that causes the Big Bang and that "something" never gets explained, which only pushes the question to the origin of "that" cause. And it usually hangs as being a sort of First Cause, a "Something" in existence, which is by far a better option than Creatio Ex Nihilio. You can include causality, entropy and similar notions to any kind of "Something" - but never to Nihilo.

True Non-Existence, event though a concept we never experience in reality, is a beautifull thing, because it has only one, clear and strict meaning. Total absence of anything and all (spacetime included). If its not that - it's "something". Of course, if it''s not Creatio Ex Nihilo, then we have to assume a past eternity of some kind (be it Primus Movens or a cyclic/paralel model). Sure - past eternity brings out problems - but not as many as a single or multiple Creatio Ex Nihilo. But Past eternity is based on factual knowledge and observation - its an extension of what we know into the unknown, rather making up new types of logics and physics.

the best way I found is to use modal logic for such issues: Everything can (quite easily and reasonable) be put into 2 categories: Actually possible and potentially possible. Actually possible are known and proven possibilities (assuming hard determinism doesn't hold, but thats a separate question), I could go left or right - a car could pass my house or it could not, etc. Potentially possible are possibilities, that "might be possible". It might be possible to go faster than light, to alter all the physical constants we know, etc. But it's not proven to be possible (and of course, the possibility never happened that we know of).

We can quite easily and rationaly posit, that there are no physical proofs and explanations for Creatio Ex Nihilo while it the same time we know that conservation of energy, causality, etc.... are proven and real constants (and that in some physical models we can show how the Past Eternal models are consistent, logical and give observable predictions).

Creatio ex Nihilo with its non-existing logic and missing proof is surely a "possibily possible" scenario, while Past Eternity is (if combined with specific physical models) an "actually possible" scenario. The first one is clearly less possible and less logical and we must conclude, that the second model is more probable.

And I come back again: Why go against Occam and favor Creatio Ex Nihilo, when we have simpler and logical alternatives? It baffles me. I can only attribute that to personal biases and/or extremley narrowminded "horse blinders" approach, that simply cannot give a complete and objective picture. Yes - accepting Past eternity means opening a Pandoras box worth of possibilities - but keeping Your eyes shut is not good, objective science.

As long as we have logical options (however complex) they will always be more probable then illogical ones. Occam favours "real" options above "potential" options.

Does the Universe need a God? Maybe not - but God definetly needs a universe and a past eternal one guarantees Gods existence if God is "actually possible" (Posthuman- or otherwise).

If I go back to the original situation: 1 healty stranger-donor to save a dozen transplant patiens and what to to: It always surprizes me why no one suggest to simply talk with the stranger, explain him the situation and ask him, if he would willingly sacrifice his life to save the other dozen. Is it so hard to imagine that such altruism (or an exchange for a small token of appreciation: commemorative plaque, nameds street/building, etc.) could be realistically expected?

Wouldn't it be rational to assume, that what/whoever designed the simulation, would do so for for the same reason that we know all inteligent life complies to: Survival/reproduction and maximizing its pleasure / minimizing pain?

I see two problems with this:

1. Alien minds are alien, and
2. that really doesn't seem to exhaust the motives of intelligent life. It would seem to recommend wireheading to us.

Wouldn't it be rational to assume, that what/whoever designed the simulation, would do so for for the same reason that we know all inteligent life complies to: Survival/reproduction and maximizing its pleasure / minimizing pain?

A priori assumptions arent the best ones, but it seems to me that would be a valid starting point that leads to 2 conclusions:

a) the designer is drastically handicapped with its resources and our very limited simulation is the only one running (therefore the question - why is it exactly like it is - why this design at all if we're talking in several "episodes")

b) the designer is can run all the simulations he wants simultaneusly and ours isn't special in any particular way besides being a functional tool (of many) providing the above max p/p to the designer

if we assume a) then the limitations/errors of the simulation would be more severe in every way, making it easier to detect what the author lists. Also, our one simulation would have to be an optimal compromise to achieve the very limited, but still max. p/p for the designer - we could talk about variety of sorts - but only variety with clear and optimal purpose would count. What is so special then in our known configuration of the physical constants? It would seem that a strong anthropic principle would apply - only a universe with inteligent (even simulated) life and physical constants similar to our own would be required for an evolutionary way for this life to evolve - or think it has evolved. I would quess that the world outside our simulation is subject of similar ways of physic and evolution as is known, in a simplified way, in our simulation - by this same anthropic principle.

If b) is the case and we're only one simualtion of many - that would assume that there are no severe restrictions on resources and computational power of the designer. Our simulation would therefore be a lot more detailed with less room (if any) to find errors or any of the kind of proof that we're living in a simulation. Parallel processing the same simulation with diferent, but relevant permutations asside - what could we tell about other simulations running in paralell with ours? That they are very different to our simulation. Since resources arent a problem - variety for max. p/p is the key. The designer could arbitrarily create simulations that are not long-term sustainable, but allow for scripts and vistas impossible to experience in a simulation similar to our own. He could use the resources to explore all relevant (or potentially relevant) possible world simulations and allocate resurces to constantly find new ones. All computationally accessible and relevant worlds would be running in parallel (because there is no need for an "experience cap"). The only limit would be that of an act utalitarian - to run those scenarios, that in the long run bring out the most pleasure.

The level of detail of the simulation is the key - if its very limited - so is the world outside it and our simulation is the best compromise (best possible world) to run - a fact that could be analysed quite intensely.

if it's very detailed (but we still managed to prove we're in a simulation), then we're only a very small drop of paint in a very big picture. But I would guess in this case that our detailed simulation would allow for additional subsimulations, that we could create ourselves. The same could be true for a), but with much greater limitations (requiring limited moemory/experiences and/or plesure loops - very limited ways of maximizing our own pleasure)

Agreed - MWI (many-worlds interpretation) does not have any "collapse": Instead parts of the wavefunction merely become decoherent with each other which might have the appearance of a collapse locally to observers. I know this is controversial, but I think the evidence is overwhelmingly in favor of MWI because it is much more parsimonious than competing models in the sense that really matters - and the only sense in which the parsimony of a model could really be coherently described. (It is kind of funny that both sides of the MWI or !MWI debate tend to refer to parsimony.)

I find it somewhat strange that people who have problems with "all those huge numbers of worlds in MWI" don't have much of a problem with "all those huge numbers of stars and galaxies" in our conventional view of the cosmos - and it doesn't cause them to reach for a theory which has a more complicated basic description but gets rid of all that huge amount of stuff. When did any of us last meet anyone who claimed that "the backs of objects don't exist, except those being observed directly or indirectly by humans because it is more parsimonious not to have them there, even if you need a contrived theory to do away with them"? That’s the problem with arguing against MWI: To reduce the "amount of stuff in reality" - which never normally bothers us with theories, and shouldn't now, you have to introduce contrivance where it is really a bad idea - into the basic theory itself - by introducing some mechanism for "collapse".

Somehow, with all this, there is some kind of cognitive illusion going on. As I don't experience it, I can't identify with it and have no idea what it is.

I would be far more careful using quantum physics in informal "philosophical" arguments. In most instances, people summon quantum effects to create a feeling of answered question, while in fact the answer is confused or, worse, not an asnwer at all. The general rule is: every philosophical argument using the word quantum is bogus. (Take with a grain of salt, of course.)

More concretely, closed quantum systems (i.e. when no measurement is done) evolve deterministically, and their evolution can be periodic.

"Physical" and "logical" are not the same thing. Even if all physical possibilities are instantiated (as Tegmark's Level IV Multiverse implies, I believe), there are logical systems that do not describe any part of reality.

No, it isn't.

Infinite time doesn't mean that everything physically possible happened. Maybe the same things kept happening over and over.