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Why it is (nearly) impossible that we live in a simulation (arxiv.org)
27 points by pseudolus 78 days ago | hide | past | favorite | 82 comments


>In all cases, the amounts of energy or power required by any version of the simulation hypothesis are entirely incompatible with physics, or (literally) astronomically large

Of course it would be. The laws of physics as we know them would exist only within the simulation.

The outer universe could have literally any rules - free energy, faster-than-light travel, more (or fewer) spatial dimensions, super-turing computation, anything’s possible.


One strand of argument for the simulation hypothesis is that future beings would conduct "ancestor simulations" to understand key events in history. Such simulations would of course use the same laws of physics (or nearly the same) to be useful. This paper, at least, refutes the ancestor simulation strand of arguments (to the extent you believe it of course)


Or it could be Half-Life 10⁹⁹, with stylized graphics and simplified rules (main action goes within another galaxy and we are a background noise). We're talking unknown unknowns here


The paper sort of gets into that as well, considering the "worst" possible simulation where particle colliders and neutrino observatories would still work.


When we simulate the weather we don’t simulate stuff at the physics level.


Just keep reading the abstract.

> Only universes with very different physical properties can produce some version of this Universe as a simulation. On the other hand, our results show that it is just impossible that this Universe is simulated by a universe sharing the same properties, regardless of technological advancements of the far future.


Who knows, it could be populated entirely by all-knowing, all-powerful beings that watch our every moral decision and intervene in subtle ways if we sincerely entreat them.


Then I have a lot of issues with the amount of tragedy and suffering they allow.


Good news is that in this scenario it’s simulated suffering and not “real” suffering.


Is my LLM experiencing real or simulated suffering? How many layers of complexity and real-time stimuli-responsiveness would make the answer to that question effectively unknowable?


Suffering is bad because people experience the suffering. There is no fake suffering.


The joke is, they aren't real people. That is what the comment implied.

Of course, from the POV of any such simulation, the simulated suffering is real within the context of the simulation.

But realistically, it's already a giant leap - a thought experiment, mostly - to wonder if we're in a simulation. To then extrapolate our IRL experiences to some parallel In-Simulation-Life (ISL) value is pushing the thought experiment to ridiculous levels.


My point though is that simulated suffering, if simulated effectively, is as real as nonsimulated suffering. The important part of suffering is that it’s experienced. The inverse of fake people experiencing real suffering is that if you put a real person in a torture machine but you somehow prevent them from experience suffering they would not be suffering. So it does not matter whether or not the people are real.

I fully understand some people disagree as you’re saying. But I believe they aren’t being intellectually honest with themselves and are actually just trying to excuse the reality of simulated suffering.


all suffering is real if it is experienced by thinking beings


Same difference, though


Imagine giving someone a chess board where there are no negative consequences. Where both players win and no one loses any pieces ever. Would that game serve a purpose?

Which has a better outcome, a mom/dad that gives their child everything and protects them from all exposure to the world, or parents that introduce their children to difficult/frustrating learning situations? As C.S. Lewis put it, what you want is a potential higher being to be a grandparent not a parent.


You can only account for personal tragedy and suffering, though -- it's impossible to determine how many other entities like you there are in a simulation. You could be the only one.


Perhaps matter that animates and takes issue with other matter suffering is the whole point, and that wouldn't be possible without suffering.


Job 40:6-14

[6] Then answered the LORD unto Job out of the whirlwind, and said, [7] Gird up thy loins now like a man: I will demand of thee, and declare thou unto me. [8] Wilt thou also disannul my judgment? Wilt thou condemn me, that thou mayest be righteous? [9] Hast thou an arm like God? Or canst thou thunder with a voice like him? [10] Deck thyself now with majesty and excellency; And array thyself with glory and beauty. [11] Cast abroad the rage of thy wrath: And behold every one that is proud, and abase him. [12] Look on every one that is proud, and bring him low; And tread down the wicked in their place. [13] Hide them in the dust together; And bind their faces in secret. [14] Then will I also confess unto thee That thine own right hand can save thee.

https://bible.com/bible/1/job.40.6-14.KJV


A confusing chapter, so I asked AI for guidance (or prayed to the simulator, if you prefer)...

AI Overview

In the Book of Job, chapter 40, God challenges Job to address the wickedness and pride in the world, highlighting the fact that only God can truly subdue the forces of evil. God uses the examples of the Behemoth (a powerful land creature) and the Leviathan (a sea monster) to demonstrate his immense power and to show Job that he cannot handle these issues himself. Essentially, God is revealing Job's limitations and his own divine power, urging him to submit to God's justice and wisdom. Here's a more detailed breakdown: God's Challenge: God asks Job if he can "tread down the proud" and "make the wicked turn to their place". This is a test to see if Job can embody God's justice and power. Behemoth and Leviathan: God uses the Behemoth and Leviathan as examples of his power. They are creatures of immense strength, representing the forces of chaos and pride that only God can control. Job's Submission: Through these examples, God is showing Job that he cannot understand or control all of God's work. Job eventually acknowledges this, expressing his humility and submission to God. Theme of Divine Sovereignty: The chapter emphasizes God's power, wisdom, and justice, contrasting it with Job's limited understanding and ability. Suffering and Justice: The suffering Job endured is a backdrop to this chapter. God uses the suffering to demonstrate the mystery of his ways and the importance of trusting in his justice.


To summarize, the Almighty is saying: "Up your game to the divine level, and we'll compare notes."

It seemed a fitting reply to the observation about having issues, though the moderation did not agree.


I had the same pain point with religion until I realize that I routinely enjoy movies, shows or books where people suffer or die in unjust ways.

Well, if I enjoy it (to some degree, because it serves the story), wouldn't some other entities do too ?


The people in the media aren't actually suffering. I don't know about you, but I wouldn't enjoy it knowing that anything was actually was in pain for my amusement. We can't even use video game as a analogy for the simulation because the creatures in video games don't actually feel, and the simulation implies we are built to have conscious experience.


> The people in the media aren't actually suffering. I would argue that from their point of view, they very well do. See "Last Action Hero" for my point. How do you know, one dimension higher from them, that they do not suffer ? Do you see the actor "winking" at you, like it's a joke ? No, from their point of view, the suffering is pretty much real.

You imagine suffering from our point of view. Try to imagine that a God might see you as you see Bruce Wayne in the comics.


I get it, it's fun philosophically, but this is an absolute non issue.

Jack Slater is just a role Arnold played and Bruce Wayne is a character. You can never produce an unintended reaction from either of them because there's nothing there to react. They aren't even simulations of people. A person in the simulation is aware of their existence in some reality and are able to react to stimulus. Bruce Wayne can't do that, it does exactly what the writer and artist will. The only place that Bruce Wayne the thinking thing exists is in our imaginations.


I didn't say anything about benevolence.


The simulation argument is that we'll make these universe simulators. Because we will in this universe, they'll be common. If they are common it's likely we're in one.

If you change that to they won't happen in this universe. That suggests they are not common. And so while we could be in a simulation the argument kind of dies off


Does not follow.

"Common" does not imply "infinitely reproducible in all directions". Something can be "common" for positive integers, but not for negative. Or common for simulations of size << U, where U represents the energy of this universe.


And at that point it doesn't matter if we're in a simulation as it could be simulations all the way down.


I present to you the halting problem.


I love this. It seems like conspiracy theory on a Universal scale.


Why is it a stance accepted in Science to arrive at dramatic conclusions like these and not realise that maybe, we are missing something ? I can't help but imagine how for most of humanity, germs did not exist, black holes did not exist, electricity did not exist, radioactivity did not exist, electrons did not exist...

Why can't we recognize that we do not stand at the endpoint of life and science but (hopefully) at one of its many segments, and that maybe not being able to calculate something does not equate its impossibility ?


Because science is made up of humans and humans like to make dramatic conclusions, because those seem to be more likely to result in attention and promotions and prestige.

It's not a weakness limited to science, believe me...


Mankind didn't know about germs, black holes, electrons, radioactivity, … for a long time but back then no one ever claimed they didn't exist, either. They were simply outside our realm of experience but at the same time there was also nothing in our experience as humans that was really constraining their existence.

Today, we have a pretty good understanding of the broad strokes of how nature works (think local energy & momentum, spacetime, quantum mechanics, etc.) Yes, we don't understand everything yet (not by a long shot) but we expect future insights do be compatible with what we've seen and measured so far[0]. In that sense, today's "laws" of nature constrain tomorrow's (updated) "laws" of nature. This is also how the authors arrives at his conclusions.

[0]: Yes, there is no guarantee for that. It could happen that physical laws change wildly from one day to the next. But this is not a particularly interesting direction for a research program, because if you start with that assumption, then anything could happen at any time, and physics as the discipline of trying to understand nature would become a rather pointless endeavor. However, the success of physics at describing nature seems to indicate that we're onto something.


I think you misunderstand what science is and how it works. Everyone understands that we are not just possibly, but in fact certainly, missing not just one something but many things. But until there is actual evidence of those things, they can't be considered.

Nobody thinks that science as it stands now is complete or even necessarily correct. All scientific knowledge is always provisional, subject to revision as evidence requires.


Because science is not looking for the absolute truth. Science is one (of many) method of knowledge generation.. which stands upon logic .. given P and Q .. we conclude X. And that will be true even if one day discover that given P and Q and R.. we conclude Y. Science is not interested in asserting statements without constraints.. for that.. you’d be better off with philosophy. And then things can get weird really quickly. Take this conclusion as example “Only universes with very different physical properties can produce some version of this Universe as a simulation” so my take can might as well be .. “oh, so the simulator has different properties”… and someone else might think “oh, so we don’t live in a simulation” and there is no way to know which one is actually true. Because we are just limited to what we know and even more so.. what we can know. So we just affirm based on a certain knowledge that we already have.


I think you're being profoundly uncharitable in that characterization of the author's work here, in that if you read the paper (and, really, even just the abstract), you'll see that they clearly understand the existence of such possibilities, and have simply chosen to limit their investigation to what their area of professional expertise (namely, the physical sciences) can assess with confidence. An illustrative quote from the concluding discussion:

Guessing how conservation laws for energy and information applies in a universe with entirely different laws, or whether they should even apply in the first place, appears impossible and this entirely prevents us from guessing whether the SH is possible in such case. For example, hypothetical conscious creatures in the famous Pac-Man video game in the ’80s will just be incapable of figuring out the constraints on the universe in which their reality is being simulated, even based on all the information they can gather around them. They would not guess the existence of gravity, for example, they would probably measure energy costs in ”Power Pellets”, and they would not conceive the existence of a third dimension, or of an expanding space time, and so on. Even if they could ever realise the level of graininess of their reality, and make the correct hypothesis of being living in a simulation, they would never guess how the real universe (”our” Universe, if it is real indeed) function in a physical sense. In this respect, our modelling shows that the SH can be reasonably well tested only with respect to universes which are at least playing according to the Physics play book - while everything else appears beyond the bounds of falsifiability and even theoretical speculation.


Because how can you account for those undiscovered phenomena? You can only imagine them, but then you stop making science and start writing sci-fi


They could just append "according to current scientific knowledge" to every sentence. But it would be a waste of time.


The probability/impossibility doesn't matter. If we are in a simulation, then there is a chance (no matter how small) the simulation would reward us for acknowledging it when the simulation ends (NG+) or punish us if we don't (your save is deleted). That outcome is a potentially huge upside/downside risk! Compared to the relatively small cost of wrong belief here and now, it's obvious you should assert we do live in a simulation.


Just pointing out that that is the case for Christianity too (not religion in general because others that I am aware of require some sort of actions be taken, although some would say that true acceptance necessarily leads to actions so there is room for debate there). Also, if the creator of the simulation did want to guide us in a specific direction, might they send avatars into the simulation with messages, rather than simply banking on individuals like yourself to come up with the “goal” on their own? I’m not coyly suggesting you must convert, just raising some thoughts that I’ve had.


Christianity requires action from a person to reach metanoia (commonly referred to as repentance), not just belief. Surface level 'I repent' is not what Christianity pushes people to explore but consistent reflecting on yourself/your actions. Christianity recognizes that you need to give people the ability to start (or start back up) at any time which often gets used as an excuse to wait to start until right before you die instead of the intended 'it is never too late to try/to start trying again'.


This sounds like Pascal's Mugging.



See also Jaguar-Paw's Wager:

"Huitzilopochtli might exist, and will punish those who do not sacrifice the hearts of defeated opponents, so I should kill my neighbor and offer his heart."


This is literally just most of the Abrahamic religions reskinned with technology.


Consider the difference between the requirements to simulate the universe and simulate a person's experience of the universe. As people in the universe, we wouldn't be able to tell the difference, but the latter would be have much lower requirements


If you were simulating two beings' experiences of the universe and they met and compared notes, you might expect little incongruities where random chance was used in the decisions necessary to generate their perspectives.

Let's say a sparrow falls and a simulated being observes it, but so does a camera, which stores the footage in an unexamined hard drive. Years later another being observes the footage stored by that camera, and up until that point there had been no point in manifesting it in the simulation. Would the wings of the falling sparrow flutter exactly the same way for the two observers? What if they met and discussed it, as part of a deliberate experiment to test the consistency of the universe? Would they agree? Imagine the computational overhead necessary in storing details that you're not sure will ever be useful. The same logic could hold true for a photon generated by an exploding star 12 billion years ago that zipped across the expanding universe and eventually interacted with some silicon in a CCD in an astronomer's camera.


Human's already have differing memories of the same events. No low resolution simulations needed for that to occur.


A properly setup experiment could distinguish signal from the noise of normal memory variation.


Indeed, you only have to simulate what one person perceives and where they explore, etc. One person's conscious experience in theory should be able to be fully simulated with very little information relative to the complexity of matter etc. You just have to simulate the senses and model the universe around a person.

And why not do that as an experiment? If science/experimentation is a useful thing - why not have the main reality and lots of individual experiments?


This is silly. If the universe is deterministic, any representation of matter can be locally simulated based on algorithmic calculation. This includes people, objects, everything. I don't need to simulate everything constantly because I know where it will be when I _need_ to simulate it.

So, any smart simulation would only be simulating a small very percentage of itself at any given time -- that part of itself being viewed or interacted with by observers. And we would have absolutely no idea how many of those observers actually reside in any given simulation. 10? 100? 1m? Who knows!

But we could take this even further and suggest that it is only the _experience_ of the universe by ourselves that is being simulated. In that case, we're not actually interacting with anything, we're only gaining the memory of having interacted with it (in 'real time'). In this case there's no physical reality at all! We're living in a large shared hallucination, that once again only 'exists' where and when we're interacting with it.

Finally, we have no idea of the time scale. The time scale in the simulation could be much slower than the outside universe. This would lower the energy required to simulate it even further.

So, no, it's totally possible we live in a simulation!


I thought chaos doesn't allow that kind of selective simulation, although maybe no one would notice that the butterfly effect only happens in places people are watching.

Ken MacLeod used a similar argument in The Corporation Wars.


Isn't it not really deterministic because you cannot know both the exact position and exact velocity of particle? (along with the other pairs of physical properties that also follow the uncertainty principle)


Any part of the universe you look at requires simuilating too much of the entire universe to get it from the state you last observed to the state it's supposed to be in now.

Time is important, if it takes too long no one is going to run the simulation.

The entire point of the simulation argument is they are fast and easy and therefore common. If simulations are common then it's likely we're in one. If you keep adding requirements that likely make them slow and hard then they are likely uncommon and the argument for us being in one disappears.


> So, any smart simulation would only be simulating a small very percentage of itself at any given time

does a falling tree make a sound if the simulation is not running? : )


I'm looking forward to the author's next work, "Why it is (nearly) impossible that an infinite number of angels can dance on the head of a pin." I understand it's based on Cantor's diagonalization proof.

I'm assuming this is a gag, I could be wrong.


One neat explanation I've heard is:

If we are in a simulation at some point we would create our own simulation which at some point will create it's own simulation etc. If we had indeed created a simulation, the chances we ARE in a simulations are great as we can be anywhere on that chain of simulations-creating-simulations. We're either the first REAL original existence, or one of infinite chain of simulations. Odds are against the real.

However, since we have NOT created such a simulation, we are either in the FIRST real existence, OR the last in line of simulations which have not yet created one. So the chance go down from infinite to 1 that we ARE in one, to 50-50 that we are NOT.


> However, since we have NOT created such a simulation, we are either in the FIRST real existence, OR the last in line of simulations which have not yet created one. So the chance go down from infinite to 1 that we ARE in one, to 50-50 that we are NOT.

This is like saying that the chance of winning the lottery is 50%: Either you win or you lose. I hope further explanation of why this is incorrect is not necessary.


There are 2 options left - either the first 'real' world, or simulated and the last in a chain of worlds in simulation. That's pretty binary.


Steelmanning this, there is one interpretation where the probability would indeed be 0.5, namely that every universe only ever simulates exactly one other universe. This would entail that there is always exactly one simulated universe that does not contain a simulated universe.

However, there is no reason why any universe would be limited to simulating one universe, so the interpretation doesn't make sense. The level of branching determines how many 'leaf' universes there are and thus the probability of being in a leaf universe or in the root universe.


I was referring to an explanation I heard, in the context of our own existence in this universe, where that explanation, in my opinion covers a 50-50 chance.



This is to a large extent a metaphysical question. Physics should not attempt to wade into this, as it cheapens the field. If there were evidence showing that this were a simulation, sure, then that’s fine, but you can’t disprove a metaphysical concept using physics.


So, you've not spoken to any string theorists, huh?


But does our universe obey Popek and Goldberg's virtualization requirements?


We have been literally simulating the "low-res Earth" as described in the paper on $500 game consoles used by 15 year olds for the past 20 years. GTA is one example.


Whitepaper contains many grammatical errors ... what else was not considered?

I don't think that necessarily negates any conclusions, but, it doesn't help the author's case.


In this era perhaps it's a plus. The paper is the direct thoughts of the authors, and hasn't been put through a LLM.


That's a really good point. I wonder if eventually LLMs will start incorporating this as a feature.


A day ago I stayed at home and saved a lot of energy for the sim operators. A view out of my window is nothing special and the sky was overcast at night.


Assuming that the outer universe is 3D. What if the outer universe was 5D or 10D


And that the number of observers in this universe will be allowed to grow infinitely.

It's entirely possible that the universe will conspire to have some clever mechanism to limit the number of observers to whatever the universe simulation can support. For all we know They have been upgrading the cluster as we advance. We don't even have a way to know if the simulation is in real time. Maybe it slows down when we have too many babies or make too many sensors, and speeds up after a plague.

But whatever the truth is, the game is whatever winning conditions you wish to make it. Some people have very personal goals, others subscribe to group goals. We don't know if there's an after.

Even when someone else gives your life meaning, you still chose to accept it. Most of us reject when someone tries to give our lives a negative meaning. That door swings both ways.


>Only universes with very different physical properties can produce some version of this Universe as a simulation.

I cannot give a formal proof to it but at the same time this feels so ... obvious?

Edit: I'm not going to complain about the downvotes but they also didn't prove s*it, lol.

Since the gloves are off now ...

"As anticipated, since EI,U ≫ EU , there simply is not enough energy within the entire observable Universe to simulate another similar universe down to the Planck scale, in the sense that there are not even remotely available resources to store the data and even begin the simulation."

It would be very stupid to even consider that a complete simulation of X could be carried out from within X and using only elements present in X.


Yeah, when I heard that the largest supercomputer in the world was going to simulate the folding of a single protein (something that takes infinitesimal time and energy in reality) it was also obvious to me that simulating the universe would be incredibly wasteful. There's plenty of room at the bottom but not that much room.

Of course this argument does not apply if the outer universe contains extra dimensions or whatever, but that isn't the kind of ancestor simulation Bostrom and friends are talking about.


Goedel's Completeness Theorem seems (to me) to support this hypothesis: No universe can contain enough diversity to simulate itself. (My adaptation of GCT to this question; he did not directly address it.)


In realtime. You run your simulated universe at one second per century here, it becomes doable.


Sure, but,

* What about simulating the simulator? Or something like that.

and

* Einstein famously showed that space and time are the same structure and it is only an illusion (to us) to perceive them as separate things. Which means "I will only simulate a second of the universe" is akin to saying "I will only simulate 1 cm3 of the universe", both are incomplete simulations of the universe but the latter makes it more evident.


If you are in a simulator, you have no idea the rate your 'outer universe' is running your 'cpu clock'. Thus it is not a valid argument that your universe could not be held in that outer one.

That's all I meant.


We're an ant farm.


Sounds like something someone running the simulation would say >.>


> our results show that it is just impossible that this Universe is simulated by a universe sharing the same properties, regardless of technological advancements of the far future

Makes enough sense to me, but I was never super well educated in the simulation hypothesis. Seems like there should probably be some heated discussion here.




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