reality is an infinite sequence of simulations???

[Electrical Banana]

i have been reading Paul Davies' book The Goldilocks Enigma,
within the chapter regarding the multiverse, he talked about how
we could all be living in a simulated universe, operated by some
higher power transcending us. in the end of one section,
he mentioned "reality might consist of an infinite sequence of
simulations, period." i found this possibility really fascinating,
unfortunately he didnt state the details, can someone please
elucidate this thing? how can it be infinite? does it have any
scientific backing? how can we prove this?

thanks!

[cosmocrazy]

Fine, so where are these higher power beings living? in another universe beyond our understanding? so who controls them and where did they come from? The question goes on....

Why do they have to be simulations? infinity means everything forever.... so all that you can and do imagine plus infinity has and will happen in this case. Infinite multi verses ideas have been knocking around for years. There is absolutely no evidence in any shape or form to suggest that this is the case. One of the ideas of quantum mechanics, "The uncertainty principle" suggests that nothing is certain until it is observed to be so, in doing the observation this affects and may set the state of reality. So it could be derived that every possible state of reality can and does happen over an infinite amount of time.

[Gobligok]

i have been reading Paul Davies' book The Goldilocks Enigma,
within the chapter regarding the multiverse, he talked about how
we could all be living in a simulated universe, operated by some
higher power transcending us. in the end of one section,
he mentioned "reality might consist of an infinite sequence of
simulations, period." i found this possibility really fascinating,
unfortunately he didnt state the details, can someone please
elucidate this thing? how can it be infinite? does it have any
scientific backing? how can we prove this?

thanks!

This definitely falls into the "turtles all the way down" category.

Maybe the "higher beings" operate within a simulation of a simulation, and so forth and so on.

[sirjon]

...he mentioned "reality might consist of an infinite sequence of
simulations, period."

I believe it is important to define the difference of the word 'reality' from 'simulation' (or virtual reality?). I think that science (the discovery of new knowledge particularly in science), is really like a never 'ending' story. Professor Hawking once mentioned that, gravity may provide a limit to the 'sequence of boxes within boxes' in our attempt to unveil the secrets of the universe". I disagree with him, in my personal view, gravity may lead us to understand why there is that sequence of boxes within boxes (but that would be another topic). God gave us five senses to determine if we're in a real world or simply a simulation of an event but the most convincing is our sense of 'feeling'. Without sensing vibrations, change in position or speed or change in temperature lead us to conclude that the event is a mere 'illusion'. I don't know the word 'simulation' as far El Banana perceived it...

[cjameshuff]

Maybe the "higher beings" operate within a simulation of a simulation, and so forth and so on.

That's the basic idea. If it's possible to simulate the universe in sufficient detail, and someone actually constructs such a simulation, they are unlikely to do it just once, and someone in each simulated universe is likely to do exactly the same. And someone in their simulation to repeat the process. And so on...so for every "real" universe, there will be a great many simulated universes. So, assuming that it is possible to construct such a simulation, and that it is actually done, odds are in favor of our universe being one of the simulations rather than a "root" universe.

Assuming that it is possible to construct such a simulation, and that it is actually done. While I think the conclusion makes sense given this assumption, I personally doubt that the assumption is valid. It would be a great waste of resources to construct such a large simulation in such detail. We do build simulations of virtual worlds, but either large simulations with limited detail, or very small simulations with deep detail. Computational power is limited, so real simulations are likely to be severely limited either in scope or in detail, depending on which is of interest to the designer of the simulation. And of necessity, simpler or shorter lived than the parent universe.

If it's us that the simulation designers are interested in, it seems far more practical to simulate our thought processes and sensory impressions (or just our perceptions, with an actual brain somewhere handling the thought processes) rather than actually simulating an actual universe supporting an intelligent life form. The results of complicated scientific experiments could simply be falsified, rather than the simulation actually being done to such detail. If we tried to build such a simulation, it would be simulated in the real universe just like we are, and the results fed to our senses. I don't see much of a motivation for this, and simply simulating a mind that perceives the real universe would be a lot more straightforward, so I wouldn't expect these full-simulations to outnumber the minds seeing the real universe...to sum up, the odds seem against me being one.

[Jens]

That's the basic idea. If it's possible to simulate the universe in sufficient detail, and someone actually constructs such a simulation, they are unlikely to do it just once, and someone in each simulated universe is likely to do exactly the same. And someone in their simulation to repeat the process. And so on...so for every "real" universe, there will be a great many simulated universes. So, assuming that it is possible to construct such a simulation, and that it is actually done, odds are in favor of our universe being one of the simulations rather than a "root" universe.


I'm not sure, but I think the point might be that it's possible that no "real" universe exists, that everything is just a simulation, and that the "roots" are all just simulations of some deeper simulation, and you never get to the bottom. It sounds absurd but it's certainly an interesting idea.

[sirjon]

I'm not sure, but I think the point might be that it's possible that no "real" universe exists, that everything is just a simulation, and that the "roots" are all just simulations of some deeper simulation, and you never get to the bottom. It sounds absurd but it's certainly an interesting idea.
Are you suggesting there are unseen powers 'playing on us'? If there exist 'Higher Beings' operating on how events would work and record both the success and failures through repeated simulations until to come up w/ perfection, why do you think this Higher Beings giving us the 'mind' to explore our existence in this world?

[coliver]

What if our existence is beamed down to us from the outer reaches of space? And we are the offspring of some higher form? We are made of star material? If you were a being made entirely of energy couldnt you create your own reality with a percieved conciousness? This is something I've considered as a possibility?

[sirjon]

What if our existence is beamed down to us from the outer reaches of space? And we are the offspring of some higher form? We are made of star material? If you were a being made entirely of energy couldnt you create your own reality with a percieved conciousness? This is something I've considered as a possibility?
I'm not so a religious person (but I believe in God), but to explain this in a scientific way, I agree w/ you Coliver...maybe, we are the 'offsprings' of some higher form...

[Gobligok]

That's the basic idea. If it's possible to simulate the universe in sufficient detail, and someone actually constructs such a simulation, they are unlikely to do it just once, and someone in each simulated universe is likely to do exactly the same. And someone in their simulation to repeat the process. And so on...so for every "real" universe, there will be a great many simulated universes. So, assuming that it is possible to construct such a simulation, and that it is actually done, odds are in favor of our universe being one of the simulations rather than a "root" universe.

No, that wasn't my point. My point was that it's "turtles all the way down," as I read the proposition. IOW, useless, if not amusing to kick around once in a while.

[coliver]

I'm not so a religious person (but I believe in God), but to explain this in a scientific way, I agree w/ you Coliver...maybe, we are the 'offsprings' of some higher form...

I've often equated our existence to a projection like a Cathode Ray Tube in a television or computer monitor. We do live in a sea of energy and are made of energy so its not too far fetched. Whether its God or some other form of entity, the complexity of life in general makes one wonder..:) Many quantum theories maintain that we create our own reality. If say our souls or conciousness were in a form of pure energy then it would make sense. Its pretty philosophical but not entirely unscientific..:)

[Weltraum]

i have been reading Paul Davies' book The Goldilocks Enigma,
within the chapter regarding the multiverse, he talked about how
we could all be living in a simulated universe, operated by some
higher power transcending us. in the end of one section,
he mentioned "reality might consist of an infinite sequence of
simulations, period." i found this possibility really fascinating,
unfortunately he didnt state the details, can someone please
elucidate this thing? how can it be infinite? does it have any
scientific backing? how can we prove this?

thanks!

I would simply have to laugh at someone who would deny God, but then come to believe in this simulation stuff. Rejecting one Creator for another, and even turning the physical universe into something maintained by some kind of machinery!

Incidentally, I've encountered a guy in another forum who believes this, or did. The Van Allen Belts are the "limits of the simulation" :)

[Weltraum]

I've often equated our existence to a projection like a Cathode Ray Tube in a television or computer monitor. We do live in a sea of energy and are made of energy so its not too far fetched. Whether its God or some other form of entity, the complexity of life in general makes one wonder..:) Many quantum theories maintain that we create our own reality. If say our souls or conciousness were in a form of pure energy then it would make sense. Its pretty philosophical but not entirely unscientific..:)

This type of thinking is always so fascinating! It leads the physicist to a kind of purposeless, Bible-free God-mankind relationship, I think. This approach leaves God an unknown, unmeasured and unmeasurable quantity, not verifiable or observable in any practical sense.

If we were made by a supreme being, it would help explain our natural tendency to believe in a higher power, would it not?

[coliver]

This type of thinking is always so fascinating! It leads the physicist to a kind of purposeless, Bible-free God-mankind relationship, I think. This approach leaves God an unknown, unmeasured and unmeasurable quantity, not verifiable or observable in any practical sense.

If we were made by a supreme being, it would help explain our natural tendency to believe in a higher power, would it not?

The barrier lies between science and philosophy. Our personal beliefs have no bearing in science. But the more science uncovers and the more intricate our universe is found to be, the harder it may become to deny the possibility of some intelligient design.

I dont want to get too much in to religion since it is a somewhat taboo subject at least in this forum, other than to say "I am the light" may hold more meaning than a biblical verse?

I try to keep an open mind to both points of view but limit my hypotheses to scientific standards. Many scientists believe in God but philosophy is in direct conflict with the scientific method. I believe it was Buzz Aldrin that said after looking down at the planet from the vastness of space it was hard not to believe in a higher power..;)

[captain swoop]

OK this thread isn't open forum for everyone to post their own pet ATM theory of creation. Ask questions of the OP and keep your own ideas for ytour own ATM threads. Keep religion out alltogether

[coliver]

EB what is your thinking concerning the source of the simulations that you are proposing? Just a random assembly by nature or an alien form of life perhaps? Or what did the book in question propose?

[sirjon]

What if we're really the 'offsprings' of aliens that accidentally crushed into this planet? Why we're the only one different from other species, keep inventing and created technology to make this part of the world 'comfortable' for humans to live in? I just keep wondering, minus the humans in this planet, what left are green lands, blue oceans and clear skies and all kinds of species in the Animal Kingdom.

[eburacum45]

We are genetically related very closely to other species on this planet, and somewhat related to every species; so we can almost certainly eliminate the possibility that we are descended from aliens who crashed here in the relatively recent past.

[eburacum45]

The Simulation Argument (as it is known) is quite convincing, when you assess the potential computation power available to a hypothestical advanced civilisation. The largest structure that such a civilisation might build could be a so-called Matrioshka Brain, an entire solar system converted into a computer. This brain could be further increased in power by using the luminosity of the central star to disassemble itself into more computational elements. Eventually a structure could be built capable of simulating quadrillions of entities as complex as humans, or, to put it another way, billions of people in millions of different ways. We could be inside one of those millions of possible simulations.

The simulating civilisation doesn't have to be aliens; it could be the humans of the future - our future selves, in fact. To explore the past, a hypothetical advanced posthuman civilisation of the future could use deconstructed Matrioshka stars to simulate billions of different versions of the past, just to see how history would develop in certain circumstances. We could be in one of those alternate history reconstructions (ancestor-simulations). As Nick Bostrom has pointed out, in his
http://www.simulation-argument.com/simulation.html


at least one of the following propositions is true:
(1) The fraction of human-level civilizations that reach a posthuman stage is very close to zero;
(2) The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero;
(3) The fraction of all people with our kind of experiences that are living in a simulation is very close to one.

[eburacum45]

As far as 'simulations all the way down', that is going beyond the scope of the simulation argument. It would be relatively easy for a posthuman civilisation to simulate many 21st century civilisations using a Matrioshka Brain- but it would be very hard for any civilisation to simulate a Matrioshka Brain on any larger computer, because that is about as big as they can get in this universe without becoming unbearably slow.

[coliver]

The Simulation Argument (as it is known) is quite convincing, when you assess the potential computation power available to a hypothestical advanced civilisation. The largest structure that such a civilisation might build could be a so-called Matrioshka Brain, an entire solar system converted into a computer. This brain could be further increased in power by using the luminosity of the central star to disassemble itself into more computational elements. Eventually a structure could be built capable of simulating quadrillions of entities as complex as humans, or, to put it another way, billions of people in millions of different ways. We could be inside one of those millions of possible simulations.

The simulating civilisation doesn't have to be aliens; it could be the humans of the future - our future selves, in fact. To explore the past, a hypothetical advanced posthuman civilisation of the future could use deconstructed Matrioshka stars to simulate billions of different versions of the past, just to see how history would develop in certain circumstances. We could be in one of those alternate history reconstructions (ancestor-simulations). As Nick Bostrom has pointed out, in his
http://www.simulation-argument.com/simulation.html

I've often equated our existence to a projection of sorts, like a CRT. A lot of mainstream science tends to agree that our world seems to be an illusion of some kind. And it wouldnt be beyond comprehension that some future mankind or an alien species could create such a thing, but the sheer size of it is what makes me think it might be beyond our abilities? Unless it was maybe an accidental event and went in to replication or something? Its possible I guess.

I dont make much of UFO stories but I havent totally discounted the notion that we are some kind of experiment for a higher intelligience. They could be experimenting with different species using the Earth as a terrarium of sorts?
There are many reports of magnetic wormholes, perhaps they zip in and out of an alternate dimension or something? Just a thought..:)

[mike alexander]

I could only guess that the 'infinite' comes from the observation that someone had to build this simulation. Which begs the question of where the builders came from, unless they are also a simulation...

Lather, rinse, repeat...

[cjameshuff]

I'm not sure, but I think the point might be that it's possible that no "real" universe exists, that everything is just a simulation, and that the "roots" are all just simulations of some deeper simulation, and you never get to the bottom. It sounds absurd but it's certainly an interesting idea.

Not that no real universe exists, but that the ratio of real universes to simulated ones approaches zero, as each simulation spawns more simulations, while "reality" only spawns simulations. Ignoring the issues of finite computing resources, we could be arbitrarily far down the line, and assuming we are equally likely to be in any one universe, simulated or real, we are more likely to be farther down a tree of nested simulations than we are to be nearer to the trunk reality, and odds of being in "real" reality (or within any finite number of steps of it) is effectively zero.

[stutefish]

My question is: Does it matter?

[Jens]

My question is: Does it matter?

What do you mean by "matter"? If you mean, will this develop into some commercially useful invention, I doubt it. If you are questioning whether we should think about the nature of reality, then I would say that it does. I don't think that whether the universe started with the big bang or is in a steady-state really matters all that much in practical terms, but it's still a question that interests me and many others.

But maybe you mean to be asking, would it make testable predictions? I recognize there could be problems there.

[Jens]

Are you suggesting there are unseen powers 'playing on us'? If there exist 'Higher Beings' operating on how events would work and record both the success and failures through repeated simulations until to come up w/ perfection, why do you think this Higher Beings giving us the 'mind' to explore our existence in this world?

Not necessarily. I think it could be a result of some natural process that doesn't require any intention. Though I don't have the vaguest idea of how that could happen. But kind of like a hologram, let's say.

[evilbill]

If it's not testable, it's not science, and IMO, doesn't matter. Simulation is another word for ID.

[cosmocrazy]

If it's not testable, it's not science, and IMO, doesn't matter. Simulation is another word for ID.

I agree, the film "The Matrix" springs to mind!

[galacsi]

I remember an old SF novel by Daniel Galouye : Counterfeit World (aka Simulachron-3).

[IsaacKuo]

The largest structure that such a civilisation might build could be a so-called Matrioshka Brain, an entire solar system converted into a computer. This brain could be further increased in power by using the luminosity of the central star to disassemble itself into more computational elements.
Bigger is not necessarily better. Bigger means bigger lightspeed delays, so the computer may be slower than a smaller one. In that spirit, I wonder if the most potent computer possible in our universe is a white dwarf computer. White dwarfs are very dense and may have a crystal structure. This crystal structure may allow for extremely densely packed wires and logic circuits.

Of course, even if we're part of a computational simulation, that doesn't mean that the "parent" universe has the same physics laws and limitations as our universe. Who cares about ancestor simulations? Couldn't it be more fun to simulate fantasy realms?

Heh. Maybe our virtual universe is more fun and interesting than the "parent" universe. If the "parent" beings think in a way similar to the way we humans think, then perhaps they'd simply pull the plug on universes which are boring to them. So we're not so much a simulation of their own boring universe but rather an amusing diversion...a screensaver, perhaps. Let's hope the user doesn't move the mouse and get back to work too soon...

[coliver]

Bigger is not necessarily better. Bigger means bigger lightspeed delays, so the computer may be slower than a smaller one. In that spirit, I wonder if the most potent computer possible in our universe is a white dwarf computer. White dwarfs are very dense and may have a crystal structure. This crystal structure may allow for extremely densely packed wires and logic circuits.

Of course, even if we're part of a computational simulation, that doesn't mean that the "parent" universe has the same physics laws and limitations as our universe. Who cares about ancestor simulations? Couldn't it be more fun to simulate fantasy realms?

Heh. Maybe our virtual universe is more fun and interesting than the "parent" universe. If the "parent" beings think in a way similar to the way we humans think, then perhaps they'd simply pull the plug on universes which are boring to them. So we're not so much a simulation of their own boring universe but rather an amusing diversion...a screensaver, perhaps. Let's hope the user doesn't move the mouse and get back to work too soon...

Or worse yet, hit delete...:)

[mike alexander]

Ah, there is a wonderful lunacy in all this, in a low-beer sort of way.

I again recommend reading The Physics of Immortality by Frank Tipler for a shot of the straight stuff.

[eburacum45]

Tipler's speculation falls down because the Universe isn't contracting, but expanding; so there is no 'Omega point' and no infinite computational heaven in the future. Bostrom's speculation can't be ruled out because future civilisations with very large (but not infinite) amounts of computational potential may well exist in our universe, and they may decide to run so-called ancestor simulations. The rest follows as a logical result of that possibility.

Present day humans have a certain fascination with the past; see the popularity of Cranford or The Birth of a Nation for examples. I can imagine (although I can't prove) that future humans or their mind-children might share a similar fascination.

[cjameshuff]

Tipler's speculation falls down because the Universe isn't contracting, but expanding; so there is no 'Omega point' and no infinite computational heaven in the future.

In ours, that is. A corollary of those speculations is that an expanding universe might be an effective way to limit the consumption of computational resources as a universe simulation progresses, increasing in entropy and in information content.

[IsaacKuo]

Bostrom's speculation can't be ruled out because future civilisations with very large (but not infinite) amounts of computational potential may well exist in our universe, and they may decide to run so-called ancestor simulations. The rest follows as a logical result of that possibility.

Present day humans have a certain fascination with the past; see the popularity of Cranford or The Birth of a Nation for examples. I can imagine (although I can't prove) that future humans or their mind-children might share a similar fascination.
Why specifically ancestor simulations, though? This, to me, smacks of Pascal's Wager. You're setting up a false choice between just two possibilities, ignoring the infinite array of other possibilities.

Present day humans might have a certain fascination with the past, but they also have a certain fascination with the fantastic. How many 3d videogames are historical, as opposed to fantastical? I pick "3d videogames" because they're more or less "simulated virtual worlds". Crude simulations, of course, but simulations with their own mathematical rules of cause and effect nonetheless.

So, let's say that a third of "simulated virtual worlds" will be historical, and the rest will be fantastical. That would give us 2 to 1 odds of living in a fantastical virtual world rather than a historical one.

[mike alexander]

Why specifically ancestor simulations, though? This, to me, smacks of Pascal's Wager. You're setting up a false choice between just two possibilities, ignoring the infinite array of other possibilities.

Present day humans might have a certain fascination with the past, but they also have a certain fascination with the fantastic. How many 3d videogames are historical, as opposed to fantastical? I pick "3d videogames" because they're more or less "simulated virtual worlds". Crude simulations, of course, but simulations with their own mathematical rules of cause and effect nonetheless.

So, let's say that a third of "simulated virtual worlds" will be historical, and the rest will be fantastical. That would give us 2 to 1 odds of living in a fantastical virtual world rather than a historical one.

So where are the amorous Amazon women swimming in chocolate? Or Chippendale's World? Or my jetpack, for that matter?

Given what's gone on in our 'reality' the past few thousand years, I can only say we are either a statistical fluke of the highest order or someone hit the sadist button on the computer.

I brought up Tipler not to suggest his extrapolations are more reasonable (they are quite mad), but to suggest that the very idea that the cloud-capped towers, the gorgeous palaces, the solemn temples, the great globe itself, yea, all which it inherit, are a bunch of ones and zeroes in some cosmic komputenmachine is a bit... off. If for no other reason than to remove all responsibility for ourselves and our actions. The nested IF loop made me do it.

[IsaacKuo]

So where are the amorous Amazon women swimming in chocolate? Or Chippendale's World? Or my jetpack, for that matter?
Like I said, the "parent" universe could be even more boring than ours.

Given what's gone on in our 'reality' the past few thousand years, I can only say we are either a statistical fluke of the highest order or someone hit the sadist button on the computer.
I prefer to think of us as a largely inconsequential side effect. If we're part of a simulation, we seem to be living in a tiny speck of it.

[djinn]

God gave us five senses to determine if we're in a real world or simply a simulation of an event...

Nah, that was Aristotle, modern neurology gives you at least five more (http://en.wikipedia.org/wiki/Sense).

Nice of the "simulators" to give us creatures all these senses, hey? I suppose it means we can feel more pain, which seems to be their aim. I mean, if I was designing a simulated universe I'd think up some sort of way for things to live without having to eat other things (alive, mostly).

[IsaacKuo]

Nah, that was Aristotle, modern neurology gives you at least five more (http://en.wikipedia.org/wiki/Sense).

Nice of the "simulators" to give us creatures all these senses, hey? I suppose it means we can feel more pain, which seems to be their aim. I mean, if I was designing a simulated universe I'd think up some sort of way for things to live without having to eat other things (alive, mostly).
Even if we just stick to Earth and life as we know it, plants manage to live without having to eat other things.

It's a big universe out there, there may be many other things out there in our universe which are living without eating other things.

As for the "parent" universe...it could be something even more horrific from your perspective. Maybe in the "parent" universe, there's no such thing as (apparently) non-sentient chemicals and minerals, so there's no such thing as "plants" which survive only on non-aware things. In the "parent" universe, maybe even the most basic "particles" have souls and the only energy economy around is consuming/torturing other souls.

Or maybe not, of course.

[The Big H]

As Nick Bostrom has pointed out, in his
http://www.simulation-argument.com/simulation.html


at least one of the following propositions is true:
(1) The fraction of human-level civilizations that reach a posthuman stage is very close to zero;
(2) The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero;
(3) The fraction of all people with our kind of experiences that are living in a simulation is very close to one.


This line of argument is flawed because it takes for granted that a computer programs that adequately simulates human consciousness is even possible. That's a pretty big claim.

[cjameshuff]

This line of argument is flawed because it takes for granted that a computer programs that adequately simulates human consciousness is even possible. That's a pretty big claim.

It's simply the assumption that consciousness is based on physical principles which can be understood and predicted. Essentially, that science is a worthwhile endeavor and that consciousness does not rely on some supernatural phenomenon that is somehow exempt from scientific understanding. This is not a particularly wild claim.

In fact, if it turned out that consciousness was proven impossible in a simulation based on physical principles, that might be considered evidence that we are in a simulation...one with simplifications in place for non-conscious matter. That is, a simulation where consciousness requires special support from the simulation, and thus one specifically intended to simulate conscious beings. How else could our existence be explained?

(If you refer to Penrose's claims that consciousness is non-algorithmic...Penrose makes the disappointingly trivial mistake of assuming that conscious beings solve uncomputable problems. That we are not limited by Godel's incompleteness theorem. While technically true, we are also not limited by needing to be right. We in fact regularly arrive at conclusions which are simply false. There's no reason to believe Turing machines can't "solve" any problem humans can, if you accept some degree of wrong or incomplete answers as you are required to do with humans.)

[The Big H]

It's simply the assumption that consciousness is based on physical principles which can be understood and predicted. Essentially, that science is a worthwhile endeavor and that consciousness does not rely on some supernatural phenomenon that is somehow exempt from scientific understanding. This is not a particularly wild claim.

It assumes (a) that consciousness is substrate-independent, (b) that it can be simulated adequately with the computing power available to posthuman civilizations, and (c) that the universe that the simulated people observe can be modelled so that there are never any mistakes or irregularities. Point (a) is controversial and Bostrom deals with (b) and (c) in what looks to me to be a pretty "hand-wavey" way. All three points are definitely open to criticism, so yeah, I do think Bostrom is making a fairly big claim. Plausible, certainly, but I think I need to see better arguments for it.


(If you refer to Penrose's claims that consciousness is non-algorithmic...Penrose makes the disappointingly trivial mistake of assuming that conscious beings solve uncomputable problems. That we are not limited by Godel's incompleteness theorem. While technically true, we are also not limited by needing to be right. We in fact regularly arrive at conclusions which are simply false. There's no reason to believe Turing machines can't "solve" any problem humans can, if you accept some degree of wrong or incomplete answers as you are required to do with humans.)

Wow, it's been ages since I looked at Penrose's stuff so my memory might be a little hazy (I do recall it was very complicated and very boring). But I don't think he just took it as a given that conscious beings can solve uncomputable problems; he actually argued his case.

[captain swoop]

OK what exactly is the ATM idea being put forward? who is supporting it? ATM is not a place for general discussion

[eburacum45]

This line of argument is flawed because it takes for granted that a computer programs that adequately simulates human consciousness is even possible. That's a pretty big claim.

Apologies; I gave the wrong set of propositions in my quote. The abstract gives the correct one;
(1) the human species is very likely to go extinct before reaching a “posthuman” stage;
(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof);
(3) we are almost certainly living in a computer simulation.

the possibility that computer simulations of human consciousness are impossible is included in option 2, in this version.

Why would a 'posthuman' civilisation make ancestor simulations? Such simulations might be a very small portion of the total number of processing operations that such a civilisation might perform; but since each Matrioshka brain could potentially hold millions of such simulations, and there could be hundreds of billions of Matrioshka brains in one galaxy alone, ancestor simulations could be a tiny fraction of the total.

I've tried (and failed) to imagine what other forms of processing operations a civilisation with vast amounts of processing power might make; here is one example of my musings.
http://www.orionsarm.com/eg-article/4a2fa7ab128b7

I suspect that a very large amount of the computational power of a posthuman civilisation would be dedicated to simulating the future, not the past; but to model the future I think it may be necessary or useful to model the past in detail ( I may be wrong in that assumption).

[eburacum45]

To address captain swoop's concerns; the ATM idea is that the universe is a simulation in a simulated universe, which itself is in a simulated universe, which itself is in a simulated universe... and so on.

I am prepared to argue for the first stage of this concept (that we are living in a simulation), even though I do not necessarily believe it.

But I have no real arguments to put forward to support Davies' idea that it is 'simulations all the way down', as I don't think that can be proved from within our (hypothetical) simulation one way or another.

[captain swoop]

Eburacum45, DO I take it that you are taking over the ATM claim made by the OP? IF so then you will be held to the rules of the ATM Forum.

[eburacum45]

I am afraid I cannot, since I do not fully support it. I can only support Bostrom's Simulation Argument (and even then only as an intellectual exercise), but not Davies' extension of that argument.

Supporting that claim must be left to the OP, if s/he wishes to do so.

[IsaacKuo]

I think this thread should be moved to OTB. It's an interesting speculation, but I don't think anyone here really takes the idea seriously (or am I wrong about that?).

(1) the human species is very likely to go extinct before reaching a “posthuman” stage;
(2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof);
(3) we are almost certainly living in a computer simulation.

the possibility that computer simulations of human consciousness are impossible is included in option 2, in this version.

Why would a 'posthuman' civilisation make ancestor simulations? Such simulations might be a very small portion of the total number of processing operations that such a civilisation might perform; but since each Matrioshka brain could potentially hold millions of such simulations, and there could be hundreds of billions of Matrioshka brains in one galaxy alone, ancestor simulations could be a tiny fraction of the total.
To me, this seems very unimpressive.

A Matrioshka brain might seem impressive compared to modern computers, but it's really pathetic when it comes to simulating a universe like ours. It FITS INSIDE our universe. It simply lacks the number of "bits and pieces" to simulate our universe, which would be many orders of magnitude greater in scope.

I also take it as presumptuous to assume that there is some "border" around Earth, beyond which the simulation ends. We see things billions of light years away, and as far as we've sent probes it seems like they are part of the simulation also. If this simulation extends to our solar system, then that's already bigger than what will fit inside a Matrioshka brain.

If we're part of a simulation, the simpler explanation is that all we can see is also part of the simulation.

I've tried (and failed) to imagine what other forms of processing operations a civilisation with vast amounts of processing power might make; here is one example of my musings.
http://www.orionsarm.com/eg-article/4a2fa7ab128b7
Why not simulations of fantastical universes? Why only ancestor simulations?

If ancestor simulations are only a small fraction of the processing power, couldn't a much larger fraction of the processing power be used to investigate completely novel simulated universes? If so, then we would have a greater chance of living in a universe essentially unrelated to the "parent" universe, than to an "ancestor simulation".

Indeed, I find it unlikely for our universe to be so similar to the "parent" universe, because a "parent" universe like our own wouldn't be "big enough" to simulate our universe.

And even if our universe is indeed an "ancestor simulation", and even if our universe is indeed simply a much smaller version of the "parent" universe (not using Matrioshka brains of course; they're far too small), then I don't see any reason to expect that we are the ancestors in question. It's a huge (possibly simulated) universe out there, so the ancestors in question may be billions of light years away.

I still think this idea smacks of Pascal's Wager. It makes sense only by first making unreasonable tacit assumptions about the scope of possibilities.

I suspect that a very large amount of the computational power of a posthuman civilisation would be dedicated to simulating the future, not the past; but to model the future I think it may be necessary or useful to model the past in detail ( I may be wrong in that assumption).
Any simulation of the future is going to require simplifying assumptions in order to simulate that future before it actually already happens. In particular, you have to simplify away the existence of the simulation itself, which means the future simulation isn't actually a simulation of the future. Well, not in any detail. If you just want to simulate, say, the cosmological fate of the universe, then maybe the existence/non-existence of the simulator program has no effect.

[eburacum45]

Why not simulations of fantastical universes? Why only ancestor simulations? Ancestor simulations may be only a fraction of the total, as I tried to suggest earier. Other simulations could be fantastical universes, or idealised versions of the real universe. What Iain Banks has called 'Infinite Fun Space'. But some at least of the simulations could be straightforward models of the known universe, attempting to predict the future; one way to check how well the simulation reproduces reality is to experimentally reproduce the past.

Note that it is impossible to reproduce the whole universe, quarks and all, in such a real-world substrate, so it will have to be modelled in some reduced form. The light from distant stars, and the behaviour of atomic particles, would have to be modelled in reduced form, and the information fed to the simulated minds of the inhabitants of that simulation.

Only in a more complex universe (with unknown characteristics) could the entire universe be modelled down to a quantum level; and the possibility of higher-order universes (for which we have no evidence, of course) leaves open the possibility of even higher order universes and the possibility of an infinite regression, as posited by Davies. But I can't imagine any way of testing for such higher-order universes.

[cjameshuff]

A Matrioshka brain might seem impressive compared to modern computers, but it's really pathetic when it comes to simulating a universe like ours. It FITS INSIDE our universe. It simply lacks the number of "bits and pieces" to simulate our universe, which would be many orders of magnitude greater in scope.

As complicated as it is to simulate, if a simulation, our universe might be considerably simplified from the "real" one containing it. This is something I tried to point out earlier, though...each nested simulation is necessarily far simpler than the containing one, so I find it unreasonable to think there's any significant degree of nesting.



If we're part of a simulation, the simpler explanation is that all we can see is also part of the simulation.

To get around this problem, I proposed earlier that it isn't a universe being simulated, but our perceptions of the universe. Simulations of actual physical systems would be limited in scope and detail to those necessary to produce the right results for experiments. It might not even simulate everything virtually, but interpolate results from real experiments. If the goal is an ancestor simulation (or simulation of alternate cultures, or alien ones, or other simulation specifically of thinking beings...), this really seems the only sane way to structure the simulation.

[eburacum45]

I'll throw this little data point into the mix, for what it is worth;
http://www.newscientist.com/article/mg20126911.300-our-world-may-be-a-giant-hologram.html?full=true

Hogan, who has just been appointed director of Fermilab's Center for Particle Astrophysics, has an even bigger shock in store: "If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram." NS is full of poor reporting these days, but maybe there could be some way of determining if our universe is grainier than it should be.

[cosmocrazy]

Why go to all the trouble of making a simulation as complicated as QM, with some GR in the mix also? :rolleyes:

[cjameshuff]

Why go to all the trouble of making a simulation as complicated as QM, with some GR in the mix also? :rolleyes:

Why not?
Finite speed of light and GR might be a way to reduce computational complexity. There is a finite volume of space you can interact with in the next second. QM might itself be a result of the simulation using simplifications of more complex rules from the universe containing the simulation. Or maybe they just want to play around with weird universes.

eburacum45: I recall seeing that his estimate of the noise used some simplifications (ignoring nonlinear effects) that caused his estimate to be high by some orders of magnitude. The noise in the GEO600 results is thus far too strong to be holographic noise.

[captain swoop]

I am minded to turn this into an OTB thread or something similar. I will consult

[clint]

I remember an old SF novel by Daniel Galouye : Counterfeit World (aka Simulachron-3).

Yep, I thought of the movie The 13th Floor (http://en.wikipedia.org/wiki/The_Thirteenth_Floor), which I think was based on that novel...

EDIT: oops, hadn't seen captain swoop's post. Sorry if this is too OT. Over and out.

[IsaacKuo]

As complicated as it is to simulate, if a simulation, our universe might be considerably simplified from the "real" one containing it. This is something I tried to point out earlier, though...each nested simulation is necessarily far simpler than the containing one, so I find it unreasonable to think there's any significant degree of nesting.
Unless the nesting only goes "up", of course.

If you start from the assumptions that everything must have a "creator", and the "creator" must be greater than what is created...then infinite "upward" nesting is the conclusion.

To get around this problem, I proposed earlier that it isn't a universe being simulated, but our perceptions of the universe. Simulations of actual physical systems would be limited in scope and detail to those necessary to produce the right results for experiments. It might not even simulate everything virtually, but interpolate results from real experiments. If the goal is an ancestor simulation (or simulation of alternate cultures, or alien ones, or other simulation specifically of thinking beings...), this really seems the only sane way to structure the simulation.
I'm skeptical about whether this is really possible, in the sense that it's possible to do and that it actually simplifies the problem.

Theoretically, it might simplify the simulation--but it introduces the perhaps far more difficult problem of monitoring the simulation to figure out what experiments are being run and what is necessary to "fake" the results.

I like the idea of running a limited simulation along with periodic backups...if the simulation people ever figure out that they are in a simulation, then you rewind the simulation to a previous backup and make some tweaks. However, this requires extra space for the backups, and the required detail of the simulation may blow up so much that you may as well just go with a full universe simulation at some point.

[Chuck]

I like the idea of running a limited simulation along with periodic backups...if the simulation people ever figure out that they are in a simulation, then you rewind the simulation to a previous backup and make some tweaks. However, this requires extra space for the backups, and the required detail of the simulation may blow up so much that you may as well just go with a full universe simulation at some point.
That's what happened to cold fusion. It worked and was sending us to the stars but the computer simulating us ran out of memory, so they changed the program and restarted us from a backup.

[Swift]

Wow, this thread brings back fond memories. A lot of summer nights in high school, arguing "maybe we're all just brains in a box, there is no reality, it is all just a dream/simulation/computer program/whatever".

Ultimately, there is absolutely no way to prove that there is a physical reality. The Matrix might be a fun movie, but you can always argue that anything you see, feel, measure, sense is just more data being fed to your brain from the simulation.

So, you either just take it as a given that there is a physical reality that one experiences, or you lose your mind staring into your navel.

[cjameshuff]

Unless the nesting only goes "up", of course.

If you start from the assumptions that everything must have a "creator", and the "creator" must be greater than what is created...then infinite "upward" nesting is the conclusion.

That places us in a very unusual position of being at or very near the end of the chain. If there's an infinitely long series of nested universes, the odds of ours being any finite number of levels above the least complex one are vanishingly small...and if we're not the least complex one, we're at least rather close.

It's possible, and if reality is a bunch of nested simulations, *some* universe has to be the one that's too simple to support a consciousness-supporting simulation. It does seem to support the idea that there's no infinite series of higher-complexity containing universes, though.

[cjameshuff]

Theoretically, it might simplify the simulation--but it introduces the perhaps far more difficult problem of monitoring the simulation to figure out what experiments are being run and what is necessary to "fake" the results.

Well, a civilization capable of construction a simulation of billions of minds wouldn't necessarily have to put all those minds in the simulation. It could dedicate a slightly-simpler mind to monitoring each and every mind in the simulation, while at worst halving the number of minds it could simulate, or the speed at which it simulates them. Perhaps they could even structure our minds to be self-monitoring.

If it only does a full-detail simulation of limited parts of reality, increasing detail on-demand as needed to supply our perceptions, it would vastly simplify things. Building the simulation around its occupants and monitoring the level of detail that needs to be modeled seems vastly simpler than simulating everything down at a subatomic level.

[IsaacKuo]

That places us in a very unusual position of being at or very near the end of the chain. If there's an infinitely long series of nested universes, the odds of ours being any finite number of levels above the least complex one are vanishingly small...and if we're not the least complex one, we're at least rather close.
Once you have infinity involved, then probability doesn't work in obvious ways.

There simply isn't a way to randomly choose from, say, the positive integers, in a way such that there's an equal probability of choosing each integer. Any probability measure inevitably assigns heavier weights to lower numbers at some point.

So, it actually would not be odd to be at or near the end of the chain.

It's possible, and if reality is a bunch of nested simulations, *some* universe has to be the one that's too simple to support a consciousness-supporting simulation. It does seem to support the idea that there's no infinite series of higher-complexity containing universes, though.
So, perhaps we're not actually too near the end of the chain, but we can see the limit of where "consciousness" is supported from here.

(BTW, this is all assuming those two assumptions that everything must have a creator and the creator is always greater than the created. I personally believe neither of those assumptions.)

[IsaacKuo]

Wow, this thread brings back fond memories. A lot of summer nights in high school, arguing "maybe we're all just brains in a box, there is no reality, it is all just a dream/simulation/computer program/whatever".

Ultimately, there is absolutely no way to prove that there is a physical reality.
Well, maybe it's all a game of deception, but maybe we're an incidental part of a simulation which is not designed to deceive us.

For example, we have videogames where particle simulations are used to provide fancy looking explosions or sparkly special effects. If there are any conscious entities incidentally simulated in them...well, we don't care.

So, for example, we might be part of a simulation whose only purpose is to create fancy looking 4d explosions in the form of superclusters. So far, our view of this simulated universe looks flat and extends as far as we can see. But if, some billions of years from now, we notice the clipping plane of the particle simulation at the edge, then perhaps this would clue us in on what's going on.

[IsaacKuo]

Well, a civilization capable of construction a simulation of billions of minds wouldn't necessarily have to put all those minds in the simulation. It could dedicate a slightly-simpler mind to monitoring each and every mind in the simulation, while at worst halving the number of minds it could simulate, or the speed at which it simulates them. Perhaps they could even structure our minds to be self-monitoring.

If it only does a full-detail simulation of limited parts of reality, increasing detail on-demand as needed to supply our perceptions, it would vastly simplify things. Building the simulation around its occupants and monitoring the level of detail that needs to be modeled seems vastly simpler than simulating everything down at a subatomic level.
It seems to me vastly more complex, rather than simpler, but it might reduce the required resources...maybe.

As a computer programmer, I'm always considering the trade-off between simplicity and performance. The simplest solution is typically some sort of brute force solution which takes the least coding effort and the least debugging effort (by a wide margin!), but it usually requires more resources in time and might require more space than a more optimized algorithm.

[eburacum45]

Personally I'd give each 'monitoring mind' at least 10x the processing power of each 'simulated mind', or the simulee might start to notice shortcomings in the simulation quite quickly. This would cut down on the total number of possible simulations somewhat, but a galaxy full of Matrioshka brains would still be able to run a considerable number of alternate versions of reality.

[IsaacKuo]

I just had another thought related to the "infinite nesting" concept.

What if most of the "higher up" universes are not naturally conducive to consciousness as we know it? Due to the way time and space work in our universe, it is not very tightly connected. We see our universe as incredibly vast, with plenty of space and time for trillions of trillions of individual lifetimes.

But imagine a tightly connected universe where light can travel infinitely fast, or time loops around. In such a tightly connected universe, there might be only enough room for one consciousness.

Or imagine a universe where "light" travels in any direction in space-time, so the universe is more like a static solution to the Laplace equation than a dynamic solution to an ODE. There could only be room for one all-pervasive "consciousness", but lacking the sense of time and movement which is familiar to consciousness as we know it.

In this case, simulation nesting is about borders and restrictions to cull away excessive interconnectedness. Life as we know it is only possible in those parts of the universe with such artificial restrictions.

[eburacum45]

But imagine a tightly connected universe where light can travel infinitely fast, or time loops around.

The possibility of 'timeloops' in computation gets some futurologists very excited. Given the opportunity for a computer to use a timeloop to check its own computations, data processing could become almost incomparably more powerful. See this link;
http://www.frc.ri.cmu.edu/users/hpm/project.archive/general.articles/1991/TempComp.html

Do I think this is possible? Not in this universe... but if it happens in higher order universes practically anything would be possible.