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Author Topic: A Good Old Fashioned Existential Thought Experiment  (Read 8065 times)

Virex

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #15 on: May 30, 2011, 05:36:36 pm »

You can never simulate any energy larger than the energy used to simulate it, no matter what sort of 'quantum magicks' you invoke, and here's why:
This is assuming the universe that's simulating ours behaves the same way and follows the same rules regarding conservation. It's all assumption.
Not necessarily. Assuming our universe ends in a big crunch (unlikely, but not ruled out), then the energy density and with that the computational limit of a unit of volume asymptotically approaches infinity. What this means that on a properly built computer, a simulation of everything that has happened before would run faster and faster, reaching towards infinite speed. Now, as it reaches towards infinite speed, it also accelerates towards another big crunch, which would enable another such computer to be built in said universe, ad infinitum.
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ed boy

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #16 on: May 30, 2011, 06:03:05 pm »

This hasn't been posted, but you might find it very relevant (warning: big image (vertically, not horizontally)):
Spoiler (click to show/hide)
Similar processes could apply for other senses (for example, you have a finite number of nerves in your body, hence touch can be encoded in such a way), which means that the total number of different lives that someone can live can be considered finite, even though the universe may be finitely complex.
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Reelyanoob

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #17 on: May 31, 2011, 04:42:07 am »

@ed boy: thanks for posting that. I had a huge argument with someone once over the idea:-

Code: [Select]
"there are infinite possibilities of human creation"
The above is the secular equivalent of a religious belief for many people. Mathematically, it's nonsense.
My argument revolved around mp3 format songs, but it was basically like your link.
Huge but finite is still finite.

@Virex: I'm not sure how your idea relates to an "outer" universe simulating ours. As our universe approaches the big crunch, there might be increased computational density in our frame of reference, but an outer simulating computer might just run slower and slower to compensate. Because we are inside the simulation, we would never notice the external slowdown, and only think that there's greater computational density.

so we could run our own virtual computer universe in the warped space-time of the big crunch, but that says nothing about what's running our own universe.

« Last Edit: May 31, 2011, 04:49:25 am by Reelyanoob »
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HollowClown

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #18 on: May 31, 2011, 06:17:04 am »

Similar processes could apply for other senses (for example, you have a finite number of nerves in your body, hence touch can be encoded in such a way), which means that the total number of different lives that someone can live can be considered finite, even though the universe may be finitely complex.

Jorge Luis Borges wrote a story similar to this, based around a library which contains every possible book.  http://jubal.westnet.com/hyperdiscordia/library_of_babel.html  The obvious issue that arose was that, in such a large library, it was essentially impossible to find anything useful (or even relevant).  Sure, there was a book that told you everything you would ever want to know about your future...but trying to find it among the 251,312,000 books in the library was futile.  There was even, by definition, a book that told you how to find any book you wanted -- but similar problems occurred when trying to find that book.

In the context of a simulation, this is actually fairly relevant;  when trying to simulate anything of even moderate complexity, there are many more states than are actually useful, by many more orders of magnitude.  For instance, there's somewhere between 1043 and 1045 possible states in a game of chess.  This, in a nutshell, is why nobody tries to make computer chess programs that analyze the game tree more than a few moves in advance -- maximum complexity of the chess game tree is about 10120, or roughly 1040 times as many atoms as there are in the observable universe.

What this means is that, to simulate a universe, you would have to work procedurally.  Given a starting state and a set of procedures, you could iterate through the various states and make the universe 'run'.  But trying to store all the possible states is outrageously expensive, and (by definition) requires more complexity than whatever it is you're simulating.  Even if you're working procedurally on one state at a time, though, your simulation still has to be less complex than the original it's simulating, because of the pigeonhole principle.  This is completely unaffected by how long it takes to process a transition between states;  any universe which simulated our would by necessity be more complex than ours, and any universe we could simulate would by necessity be less complex than ours.
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Reelyanoob

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #19 on: May 31, 2011, 08:02:47 pm »

Jorge Luis Borges wrote a story similar to this, based around a library which contains every possible book.  http://jubal.westnet.com/hyperdiscordia/library_of_babel.html  The obvious issue that arose was that, in such a large library, it was essentially impossible to find anything useful (or even relevant).  Sure, there was a book that told you everything you would ever want to know about your future...but trying to find it among the 251,312,000 books in the library was futile.  There was even, by definition, a book that told you how to find any book you wanted -- but similar problems occurred when trying to find that book.

Of course there would be books in the library with every possible untruth and plot to deceive you in it as well, as well as books which exhibit the express purpose to deliberately direct you to all the false books, while seeming to be that "perfect" catalogue.
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SalmonGod

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #20 on: May 31, 2011, 09:11:19 pm »

I used to have trouble with the concept of infinity.  The word and all it implied seemed critical to grasping all kinds of existential questions, such as free will, time, and the nature of the universe in general, but I just could not comprehend it.

I'm not exactly sure when or why, but at some point something just clicked.  I had a sudden realization that infinite (everything), is the same as nothing.  The concept seemed really simple after this.  I could even relate it to the basic number line, where the sum of all numbers (positive and negative) is 0, which is also supposed to represent nothing.  In essence, infinity is a singularity.  A wholeness.  A nothing that becomes something only when divided into parts.

I've since related this to a question that was posed in my metaphysics class about the likelihood of god based on the seemingly intelligent construction of the universe.  The laws of physics are composed of variables that would unenable life as we know it if altered by the slightest fraction.  It seems like everything was designed specifically to enable us.  So do we hand-wave it as a matter of pure chance, despite being astronomically unlikely, or do we consider the notion that these circumstances were constructed intentionally?

I had a strong intuition that neither answer was correct, but no proper response at the time.  Today I think that there really is a sort of infinite multiverse, where non-existence is equal to all potential states of existence.  Ours exists by necessity, just as every other potential also exists in the same sense.

This is similar to the box full of videos containing all potential life experiences, but with some differences.

It doesn't really prove anything but the finiteness of human experience.  Nothing necessitates a finite potential variety of senses to compose life experiences from.  One video could also take place within an infinite variety of contexts which have no bearing on the content of that video, such as variables in distant galaxies which have no interaction with the character.

Of course I'm no scientist or mathematician or great philosopher, so I could just be spouting rubbish.  This is just stuff that fits together in my head.  Thought I would share.
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HollowClown

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #21 on: June 01, 2011, 12:03:44 am »

I've since related this to a question that was posed in my metaphysics class about the likelihood of god based on the seemingly intelligent construction of the universe.  The laws of physics are composed of variables that would unenable life as we know it if altered by the slightest fraction.  It seems like everything was designed specifically to enable us.  So do we hand-wave it as a matter of pure chance, despite being astronomically unlikely, or do we consider the notion that these circumstances were constructed intentionally?

As I see it, the mathematical issue with the whole "anthropomorphic principle" debate is that you can't look at the universe in terms of probability (analyzing what's likely to happen);  you have to look at it in terms of statistics (analyzing what has happened).  And given that the statistical sample size is a single universe, we don't have a large enough sample to use statistics in any meaningful way.

A good analogy here is poker hands;  the odds of receiving any given five-card hand by drawing from a random 52-card deck are 1/287414400.  If you draw a royal flush on the first deal, you can look at your hand and say "gee, it's pretty unlikely that I'd draw that hand" -- but you could say that equally well for any hand you drew, regardless of what hand it was.  Now, if you just drew 10 royal flushes in a row, you can statistically say that the game is likely to be unfair.  But if it turns out that the game is actually fair (and you've just seen a ridiculously unlikely set of happenings), then the probabalistic odds of you drawing any given hand in the next round will still be 1/287414400.
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Lagslayer

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #22 on: June 01, 2011, 01:05:32 am »

If the universe is infinitely large, then statistically, everything that is possible has already happened, is happening, and will happen again, at every single point in time, somewhere. Assuming everything is ultimately not random (the basis of all physics), then an "equasion of the universe" would exist, but be infinitely huge as well. In an infinite universe, the whole picture could never be seen, so a complete pattern could never be formulated. The smaller the picture we look at, the more discrepencies our conclusions will have in comparison to the ultimate equasion.

If the universe is finite in size, then the equasion would be finite in length, and, theoretically, could be recreated in it's entirety.

Further, knowing more of the equasion continues to eliminate probability, as we would know what is going to happen.

counting

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #23 on: June 01, 2011, 02:21:49 am »

Taoism essentially views the universe this way -- as a grand self-regulating, procedural system (the Tao) which produces all natural phenomena in the universe. Without a consciousness and without an "overseer". So in terms of the analogy, the program is running on autopilot. And for most interpretations, wasn't programmed. It's either just always been there, or arose spontaneously out of random noise.

You left the part that the universe will balance itself out, in every aspect. Every action against the 'Dao' will have a equal punishment. (not just reaction). And it's automatically done, like a game's karma system.

Jorge Luis Borges wrote a story similar to this, based around a library which contains every possible book.  http://jubal.westnet.com/hyperdiscordia/library_of_babel.html  The obvious issue that arose was that, in such a large library, it was essentially impossible to find anything useful (or even relevant).  Sure, there was a book that told you everything you would ever want to know about your future...but trying to find it among the 251,312,000 books in the library was futile.  There was even, by definition, a book that told you how to find any book you wanted -- but similar problems occurred when trying to find that book.

In the context of a simulation, this is actually fairly relevant;  when trying to simulate anything of even moderate complexity, there are many more states than are actually useful, by many more orders of magnitude.  For instance, there's somewhere between 1043 and 1045 possible states in a game of chess.  This, in a nutshell, is why nobody tries to make computer chess programs that analyze the game tree more than a few moves in advance -- maximum complexity of the chess game tree is about 10120, or roughly 1040 times as many atoms as there are in the observable universe.

What this means is that, to simulate a universe, you would have to work procedurally.  Given a starting state and a set of procedures, you could iterate through the various states and make the universe 'run'.  But trying to store all the possible states is outrageously expensive, and (by definition) requires more complexity than whatever it is you're simulating.  Even if you're working procedurally on one state at a time, though, your simulation still has to be less complex than the original it's simulating, because of the pigeonhole principle.  This is completely unaffected by how long it takes to process a transition between states;  any universe which simulated our would by necessity be more complex than ours, and any universe we could simulate would by necessity be less complex than ours.

Reminded of me the day trying to build a working CPU and even fully functional computer "in Minecraft". And most people will ask us, can we run minecraft in this minecraft computer? This explained a lot questions about viability. But it's going to be a very slow minecraft' minecraft with FPS of 1hrs/frame I/O speed, and resolution of 20x30 pixels of something, and RAM only 32 to 128 bytes at max.
« Last Edit: June 01, 2011, 02:28:48 am by counting »
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Grek

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #24 on: June 01, 2011, 09:14:14 am »

I'm sorry, but almost everything that Another (and most of the rest of you, for that matter) has said in this thread is false. As in, the opposite of true. He was correct about the observable universe being finite in size and, suprisingly enough, the bits (pardon the pun) in his second post about everything in the universe being entangled with everything else, but that was about it.

Quantum mechanics does not mean that "particles cannot exist in precisely defined states", it means that particles do not exist. The universe is made out of amplitude configurations, not particles and waves. The uncertainty principle results from position and momentum being the same measurement on a quantum level, not from there being some sort of laplacian demon that prevents scientists from observing the position and momentum of a "particle" simultaneously.

Now, that doesn't mean that you can compute the universe on your computer. As a consequence of the incompleteness theorem, it is not possible to simulate a computer simulating itself and, thus, you would either have to model a universe other than your own, or create an imprecise model of your own universe that had a great big blank spot on your output where the computer is and constantly increasing errors rippling outwards from this noncomputable blank spot.

Similarly, Eagleon's reply that uncertainty "looks alot like a compression algorithm" is just plain wrong. Current models of physics predict that no data is being "deleted" anywhere in the universe itself, nor filled in and nothing even remotely similar is happening. So, while it is possible that we are living in a simulation and the Dark Lords of Beyond the Matrix are constantly futzing with the code our universe is made from, we have no idea if that is the case and, in principle, have no way of ever finding out if they wanted to prevent it.

I'm not going to attempt to tackle alway's post about simulating "energy layers" and nesting simulations together to simulate a universe with physics that allow for better simulations than the top level universe can output, since, so far as I can tell, it is almost pure gibberish from the standpoint of information theory and QM.

Another's third post, claiming that we are in a simulation, while more coherent, is still not true. It stretches the meaning of "simulation" to the point where the term ceases to mean anything close to the common english meaning, or any technical use of the word that I am aware of. An object is not a simulation of itself. It is definately not an infinately nested simulation of itself. It is itself, nothing more, nothing less.

tl;dr version: Grek nerdrages about people misapplying quantum physics and information theory. While the universe is only noncomputable if you insist on using a bad model of the universe, there is absolutely no reason to assume or even hypothosize that we live in a simulation of any sort.

As to the original questions, "If we are living in a simulation, what are we?" and "What happens if the simulation halts?", the answers are quite simple: "'You' are a subset of the amplitude configuration that is the universe, existing and changing from second to second based on the laws of physics, as defined by the arbitrary rules laid out in the simulation." and "We cease to continue to exist.", respectively.
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Another

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #25 on: June 01, 2011, 11:34:44 am »

I suppose that the main disagreement arises from using different interpretations of QM. I prefer Copenhagen interpretation with collapses and you seem to operate within a variation of ensemble interpretation that tries to get rid of wave function collapses at all costs. You would probably mention it if you use Bohm's interpretation or others with hidden variables.

For a significant share of QM interpretations and a significant share of modern definitions of "particles" they certainty do exist.

The out of context quote really changed it's original meaning. I was referring to being in a state with precisely defined coordinates and at the same time being in a state with precisely defined impulse. You don't claim that it is possible, do you? Somehow you just managed to ascribe a different interpretation to my words.

As for my last post - you got the meaning of the post precisely as it was but missed the intentions. I made that excursus in tautology to highlight where the speculations about simulation of a universe inside a universe were heading. It is also interesting to observe at which exact point the meaning of a word becomes meaningless. Is a "perfect simulation" phrase already meaningless in some contexts?
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Reelyanoob

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #26 on: June 01, 2011, 12:08:13 pm »

If the universe is infinitely large, then statistically, everything that is possible has already happened, is happening, and will happen again, at every single point in time, somewhere.

That's assuming infinite variety, which is not automatic just by having infinite size itself.

There could be 1 single boring planet, then and endless expanse of gas. Sure, every possible pattern of gas cloud may exist, but not every potential pattern.

Cantor's theorem of multiple possible infinities may shed some light on this. e.g. :

"infinity1" is the counting numbers (integers) (i'm simplifiying Cantor's terminology a bit)
"infinity2" is the real numbers (between 2 arbitrary points, e.g. 0 and 1)

Cantor's proof shows that infinity2 > infinity1, actually it's greater than infinity1^infinity1

A good way to understand how these different infinities work mathematically, is to realize anything mesurable with infinity1 can be enumerated by an algorithm / turing machine (given infinity1 steps). It's also the same as saying two mathematical sets have the same cardinality.

Anything measurable only with infinity2 cannot be enumerated, even in an inifinity1 number of discrete steps.

This is a fundamental limit of ALL computation and logic systems.
« Last Edit: June 01, 2011, 12:19:38 pm by Reelyanoob »
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Lagslayer

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #27 on: June 01, 2011, 12:19:35 pm »

If the universe is infinitely large, then statistically, everything that is possible has already happened, is happening, and will happen again, at every single point in time, somewhere.

That's assuming infinite variety, which is not automatic just by having infinite size itself.

There could be 1 single boring planet, then and endless expanse of gas. Sure, every possible pattern of gas cloud may exist, but not every potential pattern.

Cantor's theorem of multiple possible infinities may shed some light on this. e.g. :

"infinity1" is the counting numbers (integers) (i'm simplifiying Cantor's terminology a bit)
"infinity2" is the real numbers (between 2 arbitrary points, e.g. 0 and 1)

Cantor's proof shows that infinity2 > infinity1, actually it's greater than infinity1^infinity1

A good way to understand how these different infinities work mathematically, is to realize anything mesurable with infinity1 can be enumerated by an algorithm / turing machine (given infinity1 steps).

Anything measurable only with infinity2 cannot be enumerated, even in an inifinity1 number of discrete steps.

I think you've misunderstood my statement. I never said everything imaginable is possible, but the everything that is possible has already happened, is happening, and will happen again. Though, I should have clarified that this assumes time has no beginning or end. It also assumes that everything is cyclical, as an equasion describes a pattern.

Or did I misinterpret your response? I'm not familiar with Cantor's theorem, and I had to look it up just now.
« Last Edit: June 01, 2011, 12:21:18 pm by Lagslayer »
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Reelyanoob

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #28 on: June 01, 2011, 12:44:31 pm »

The Cantor stuff was added more out of interest than a "refutation" of what you wrote.

What you wrote would be pretty much correct if view the whole universe as a chaotic equation. Basically the argument would be that every point on the strange attractor would be visited eventually.

But you can only loop around the structure infinity1 times (because the loops are sequential, therefore countable and enumerable, and fall under Cantor's first infinity).

So, if the universe has continuous variables underlying it, there will always be infinity2 possible tracks the universe's phase state equation missed, in between each of the infinity1 tracks that was actually travelled upon. There's no possible way such a universe could be fully simulated, even by an infinitely large turing-complete computer. You could only approximate it at best.

If, on the other hand it's all discrete quantum values all the way down, then the system should be able to travel every possibility, and a corollary would be the universe could be theoretically modelled on an infinite turing-complete machine, even if infinitely large.
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Lagslayer

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Re: A Good Old Fashioned Existential Thought Experiment
« Reply #29 on: June 01, 2011, 01:23:30 pm »

Oh.
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