I am not questioning whether the simulation topic is outside science. I am asking what evidence there is or could be to resolve whether we are or not.

Living in a simulation has been a topic for philosophy since at least Descartes, with his 'evil demon not less powerful than deceitful'. Zuangzhi's 'Now I do not know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man' could be argued to be a statement of the same idea. What I am interested in is, is can we get beyond speculation and make headway on this? How does the evidence stand, what tools do we have, and what implications might the different answers have?

Here I quickly summarize some of the main positions:

  1. "Are you Living in a Computer Simulation?" [PDF] (2003), Nick Bostrom, makes the case we are in a simulation, on the balance of probabilities

  2. "Quantized gravitational responses, the sign problem, and quantum complexity" (2017), Ringel & Kovrizhin, makes the case such a simulation is impossible using classical computers. But that leaves quantum computers.

  3. "The Case for Libertarian Compatibilism: A Brief Overview" (2014) gives a more detailed idea of what being in a simulation might mean, as a kind of peer-to-peer reality

  4. "Fermi Paradox: a simulation solution" [PDF] demonstrates a serious argument that the simulation hypothesis is the best answer to the Fermi Paradox. Although as recently discussed on here, the existence of this paradox is open to dispute, and relies on a range of assumptions.

Anyone got anything else evidence based? Any models, or discussions of implications?

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    Comments are not for extended discussion; this conversation has been moved to chat.
    – user2953
    Commented Feb 4, 2018 at 12:38
  • FYI - My new series "Saints and Simulators" will explore the answer to your question at length. Commented Jan 24, 2019 at 14:15
  • Reword "simulation" as "magic show" and then read this so-called eastern story in 2 versions
    – Rushi
    Commented Jun 3, 2019 at 4:46
  • I personally do not see what is the difference between being in a simulation and non-simulation, because : if we are in a simulation then this Universe is simulated in another computer, machine, mind...etc. And if it is not, then we already know that everything is a simulation in our brains like this cup of coffee I hold in my hands now. My brain simulates some kind of information that is unknown, shapeless, spaceless, timeless to construct what I perceive and taste as a cup of coffee. For suppose if we are in a simulation , then our brains do not exist, but there is computer where it happen
    – SmootQ
    Commented Aug 28, 2019 at 16:05
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    It's just a matter of flavor ... not a matter of whether it is true or not, whether it is a simulation running in your material brain, the mind of God, a computer... it is all considered a simulation, no matter who or what material runs it . But in the end, there must be something that is fundamental, that is not simulated, and that is itself shapeless, colorless, spaceless and timeless because it is not simulated by a brain to take these qualities.
    – SmootQ
    Commented Aug 28, 2019 at 16:06

17 Answers 17


I would like to argue that the topic (especially the search for proof for it) is rather useless. With a search for evidence, this topic is very similar to the topic of the search for evidence that God exists - which is, naturally, an assumption that brings the term "God" into a field it simply cannot exist in. You can't search for an ontological evidence for something that by definition isn't in the ontological field (or, at least not in the human sense of ontology).

If you want to talk in the logical field, then sure, you can present many arguments for and against the simulation argument, but from your description I see that you know at least some that's enough.

So, my point is, the question is pretty much "worthless" (not really, or else I wouldn't want to answer it, so it is worth replying to at the very least), as a search for evidence in simply not realizing the difference between the fields in which evidence lies and the simulation argument exists.

And for a final note, I think Kurzgesagt (a Youtube channel) presented some excellent points on the hard time it'll be for "aliens" to create a simulation in which we exists (although it does assume these "aliens" live in the same world we live in, with the same physical laws limitations we have, but it's still a nice video to watch - they have amazing animations skills ;).

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    It involves testable predictions, surely? The Bostrom argument argument points out we will run simulations sooner or later, but they must have limits in scale and complexity. So we look for those. It's as ontological as the anthropic principle, in that even if it may not be falsifiable in the end, it is indicative and can guide our thinking. Whereas god is usually just a deus ex machina, a magic black box
    – CriglCragl
    Commented Feb 1, 2018 at 20:51
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    @CriglCragl, any simulation can only be detected from the inside by performing a measurement and finding a discrepancy between the results and what would have resulted if the measurement had been performed outside the simulation. Without access to the outside of the simulation, there's nothing to compare against and no way to tell simulation from reality.
    – Mark
    Commented Feb 1, 2018 at 21:59
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    @CriglCragl what Mark said should suffice (and I would like to add that in the experimental-view, I think it would be amazing to try and get AI to try and learn about itself from inside, as many scientists [probably falsely] consider AI to be more advanced then human brain, so I think it could be a perfect experiment for such arguments). And I would like to state that what Mark said is exactly what I mean by different fields of knowledge - you can't possibly assume to get evidence (or more generally, any kind of empirical experience) from the non-ontological field. That is the "outside". Commented Feb 1, 2018 at 22:17
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    @CriglCragl which assumptions would you like to make that'll bring the possibility to claim otherwise? Commented Feb 2, 2018 at 0:32
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    @CriglCragl OK so those aren't evidences, those are theoretical ideas, which of course can be made, but on the exact same level I can just tell you "just imagine an outside world in which the physical laws we know simply don't exist, the boundaries we have are way wider in that world", for example. Commented Feb 2, 2018 at 13:01

I propose that we cannot know whether we are living in a simulation.

  • One of the ways to detect a simulation supposedly is to detect errors from the inside. But there is no reason whatsoever to believe that our version of the universe has anything to do with the real reality. Every last single piece of our physics etc. could be artificial, hand-picked by our creators (or just by a deep learning machine of theirs, maybe?). We cannot reason about their reality, having only our simulated reality as base. We have no way to see if they made an error in our simulator by perceiving a seeming contradiction in our own universe. There will always be the possibility that our theories are simply wrong or incomplete.
  • The complexity of creating such a simulator: We feel that we know a lot about quantum mechanics, black holes and other complicated topics. But compare what we know today (and what kind of technology we have today, both for doing physics, as well as our computing power) with what we knew/had 50 or 100 years ago. Think about what we could have in 50 or 100 years. Absolutely impossible to tell. Now place our simulators, say, 1000 years into the future. There is no hope that we would even recognize what they are doing. We cannot argue in any form or fashion whether building such a simulator would be physically or logistically possible or not (plus, we do not even know the limitations of the "real" universe).

(As an aside, Nick Bostrom does not make the case that we are living in a simulation; instead he - using pure logic, no philosophy, gives 3 possible scenarios; he does not give a probability of which one would be the most likely in our specific case. He says we should look at his three solutions with equal probability, which, to me sounds like he correctly states that we just don't know.)

(Second: that other paper about Fermis Paradoxon contains no hint about us living in a simulation, at all. The authors wrote a simple simulator which makes it possible for them to simulate the long-term life of civilizations - in the scale of 1 million years being one step of the simulation. Hence totally unrelated.)

  • Logic, is not part of philisophy now..? Extinct, boring, or in a simulation? He says we should give equal weight. We aren't talking about a Cartesian demon. Clearly our reality can be investigated logically, systematically, and responds in consistent ways. We can look for ways to put limits on options, given conscious assumptions. You seem to prefer, only make unconscious assumptions, and don't play with them or everything would be up for grabs. Granularity, scale, highly complex events with unpredictable outputs that would demand great computations, discontinuities. All could give insights
    – CriglCragl
    Commented Feb 2, 2018 at 0:12
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    @CriglCragl, I do not really understand what you are trying to say. But let me address the pure logic; no philosophy thing. It means that he is building a simple mathematical model of what he is trying to say and then assigns probabilities. As he has no knowledge about the "input probabilities" he can make no assertions about the "output probabilities", and he doesn't do so. His well-done paper is much closer to physics/maths than philosophy (and sure, you can treat all them as one if you prefer). On the rest of your comment, indeed, I prefer the viewpoint I wrote in my answer.
    – AnoE
    Commented Feb 2, 2018 at 0:27
  • I'm think the general gist here is good, but I think point three could be elaborated upon. I'm not sure why you think it's likely that the simulator would even know if any minds/life sprung up inside the simulation. If your goal for the simulation was anything other than observing all possible minds, and possibly even then, it would be very possible to create a simulation which may or may not give rise to some form of conscious minds as just a side-effect, without implementing any introspection that could detect those minds.
    – mtraceur
    Commented Feb 2, 2018 at 3:57
  • @mtraceur, thanks for the point. My last two arguments were somewhat weak, I have removed them and elaborated the other two a bit more.
    – AnoE
    Commented Feb 2, 2018 at 7:22
  • Anyway simulation will end when the sun swallows the earth
    – Wiseman
    Commented Apr 23 at 20:43

To focus on the title of the question, there is rather little active research being done around this question, but I'll share what I know.

First is a paper from 2012, Constraints on the Universe as a Numerical Simulation (Beane, Davoudi, Savage). This paper talks about running low level physics simulations that scientists currently perform, and draws comparisons to a theoretical computer simulation of our universe. They theorize about measuring how certain high energy particles are distributed, and provide an upper bound to the size of a grid-like simulation of the universe. However, our most accurate measurements are still orders of magnitude away from being able to determine anything. They close with the following:

Nevertheless, assuming that the universe is finite and therefore the resources of potential simulators are finite, then a volume containing a simulation will be finite and a lattice spacing must be non-zero, and therefore in principle there always remains the possibility for the simulated to discover the simulators.

Next is a recent paper from 2017, On testing the simulation theory (Campbell, Owhadi, Sauvageau, Watkinson). This paper is a bit more philosophical than the previous. There's a bit of discussion on the nature of reality, i.e., "the collapse of the wave function" and to paraphrase "what does it mean to be seen?" The focus is on quantum mechanic effects and present experiment(s) to probe how observers interact with and affect (and effect even) particle interactions. They draw a comparison to video games: often, compute resources are saved by not rendering something that can't be seen. Does something like that happen in the real world (going back to the wave function collapse discussion mentioned earlier)? The paper assumes that observing such an instance of reality suddenly being rendered (or suddenly being rendered in higher detail) would imply that we are in a simulation, but I think the conclusion is not so strongly implied by the premise.

I can't speak to how feasible any of the experiements in the second paper are.

I'm sure there are other relevant scientific papers, but these were all I came across when I was researching the topic (briefly) not too long ago.

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    Whatever world is simulating us, they picked our physics to suit their goals. For us, simulating QM/QED/QCD would be a computational nightmare, especially because of the Bell inequality (it precisely says our universe computes gigantic amount of unneeded stuff that gets immediately thrown away). Apparently they decided to use this model... maybe such simulation is quite easy in their physics?
    – kubanczyk
    Commented Feb 1, 2018 at 22:52
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    @kubanczyk I think part of the motivation for the "we live in a simulation" theory is the idea that quantum effects are defects in the simulation, rather than desired effects in the simulation. Something like "the rules don't know what to do in this circumstance, so just pick something so the simulation doesn't crash". Of course QM is more delicate than that, but that's the idea.
    – Ian
    Commented Feb 2, 2018 at 16:06
  • I couldn't disagree more @Ian. Theories help us to predict stuff when we look around. Mixing it with emotions - like calling what you genuinely see a "defect" or "glitch" - makes you only more liable to errors. QM is incompatible with human intuition, but it's a fact about humans, not about QM. Consider that thought experiment lesswrong.com/lw/ps/where_physics_meets_experience
    – kubanczyk
    Commented Feb 24, 2018 at 10:16

Of course it is possible that you are "living" in a simulation right now!

I'd say it is about 50% chance. we call it dreaming and it happens every night.

Well, you might say, that is pure nonsense, for I know I'm not dreaming right now. But do you really?

I dreamed last night that I was in Germany, in a house which looked out on a ruined church; in my dream I supposed at first that the church had been bombed during the recent war, but was subsequently informed that its destruction dated from the wars of religion in the sixteenth century. All this, so long as I remained asleep, had all the convincingness of waking life. I did really have the dream, and did really have an experience intrinsically indistinguishable from that of seeing a ruined church when awake. It follows that the experience which I call “seeing a church” is not conclusive evidence that there is a church, since it may occur when there is no such external object as I suppose in my dream. It may be said that, though when dreaming I may think that I am awake, when I wake up I know that I am awake. But I do not see how we are to have any such certainty; I have frequently dreamt that I woke up; in fact once, after ether, I dreamt it about a hundred times in the course of one dream. We condemn dreams, in fact, because they do not fit into a proper context, but this argument can be made inconclusive, as in Calderon’s play, La Vida es Sueno. I do not believe that I am now dreaming, but I cannot prove that I am not. I am, however, quite certain that I am having certain experiences, whether they be those of a dream or those of waking life. — Bertrand Russell, Human Knowledge: Its Scope and Value

As for the possibility that we are living in a simulation run by some other "people" one world up, I'd say that idea, in my opinion, is just as sensible as last night's dream, and attempting to seriously analyze it, just as silly.

Reality is incomprehensible and mysterious as it is, and the idea of an imaginary one world up, doesn't make an iota of a difference.

Unless of course, it is one of the ideas you are currently playing with, on your way to personally waking up.

And now that I have claimed above that a serious analysis of the simulation hypothesis is silly, I will add my personal silly analysis of it. It is written from a Buddhist / Advaita / Sufi / Hasidic standpoint:

  1. Reality is mysterious, in the sense that it transcends reason and logic and human capacity to comprehend it. It is unspeakable. Unthinkable. The simulation hypothesis on the other hand is a simple thinkable and intelligible idea, just like life after death, or any other silly metaphysical idea about our reality. As such, it does not add or change, or explain anything really. In particular, it does not make anything less real than it already is.

  2. Most proponents of the simulation hypothesis conceive of it as a computer simulation or a computational simulation. However, the day you find that which Tibetan Buddhist call self-knowing awareness, or Advaita people call Atman, or Sufis and Hasidic people call Godliness, you will know with certainty that reality cannot possibly be explained as a computation. In fact, the belief that reality may possibly be a computation, is an indication that one is, like almost everybody, still asleep.

  • So, you conclude, Bertrand Russell is just silly? Lucid dreaming offers various techniques for determining if you are in a dream. Buddhist theology concludes all beings are in a dream, and offers wide ranging and complex analysis of it, towards waking up. All, just silly? Or, is that description better applied to dismissing the concept without analysing it..?
    – CriglCragl
    Commented Feb 3, 2018 at 16:37
  • 1
    You misunderstood me. I did not imply Russell is silly. On the contrary, I quote him as a reference to my claim that one cannot be sure one is not dreaming right now. I am aware and experienced in lucid-dreaming. It does not offer techniques that let you determine with certainty that you are dreaming. I recall numerous occasions where I have failed to realize I was dreaming in fantastic circumstances. in one occasion I was examining my hand, which had three fingers, to see if it looks normal, and I concluded I was not dreaming.
    – nir
    Commented Feb 3, 2018 at 19:43
  • As for Buddhism, I am familiar with it and I practice some of its teachings. It is from a Buddhist standpoint that I say that reality is mysterious enough to render the simulation hypothesis nonsensical. I will add an explanation to the answer.
    – nir
    Commented Feb 3, 2018 at 19:57
  • Even if you count dreaming as being in a simulation and assume that you always believe yourself to be awake when dreaming, we aren't asleep 50% of the time, so that's only a ~33% probability that we're in a simulation. That may seem pedantic, but if we're to do any sort of analysis of a problem that can't be answered definitively, we need to be careful about how we use probabilities, and shouldn't be so careless as to discard the prior probabilities when they're easily available.
    – Ray
    Commented Feb 4, 2018 at 23:32
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    Great answer. The only "loop hole" is your claim in #2, that we will know with certainty that reality is not a simulation. While I do agree on that 100%, for the rational mind it is just an unprovable claim that adds nothing to the understanding of the topic. However, as I see it, that is just the way it is. Our mind simply won't understand reality on that level, no matter how much we try. Commented Feb 5, 2018 at 7:29

No, we're not living in a simulation. See my question https://physics.stackexchange.com/questions/377516/ and especially see John Rennie's answer to it, citing the relevant research.

In addition to that, see Mermin's article http://physicstoday.scitation.org/doi/10.1063/1.880968   A (legal) pdf is downloadable from http://www.physics.smu.edu/scalise/EPR/References/mermin_moon.pdf     In particular, the "gedanken experiment" section, discussed on pages 4-9, involves an EPR apparatus, and demonstrates that the observed results preclude the possibility of instruction sets. That is, the behavior of the separated components of the entangled system cannot be reproduced by (computer-like) instructions.

So, to repeat, no. This entire universe-is-a-simulation stuff is utter nonsense. Utter nonsense. Utter nonsense. Utter nonsense. (I seem to be stuck in a loop)

  • Liking the Mermin paper (also, it makes me wonder if it's written by a merman-moomin). Rennie's answer and link doesn't seem to settle anything though. It's a prediction based on specific dubious assumptions, tested only to a certain unidentified degree which clearly won't correspond to the Planck scale..
    – CriglCragl
    Commented Feb 2, 2018 at 12:45
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    I think you are misunderstanding hidden variable theory as presented by Einstein, Podolsky, and Rosen. (1) The linked paper uses "instruction," but it doesn't mean "computer instruction as part of code in the simulation hypothesis," it means hidden variables. (2) EPR paradox/"instructions"/hidden variables isn't evidence for or against the simulation hypothesis.
    – BurnsBA
    Commented Feb 2, 2018 at 14:34
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    I am not sure why you summarize physics.stackexchange.com/questions/377516/… as "No, we're not living in a simulation". See "Since the conclusions are only as reliable as the assumptions that went into them, and since we have no idea what technology super intelligent aliens would be using to simulate us I think it would be wise to treat this area with care." from physics.stackexchange.com/questions/377516/… Commented Feb 3, 2018 at 11:59
  • "That is, the behavior of the separated components of the entangled system cannot be reproduced by (computer-like) instructions." — This is not true. What is impossible is that it can be reproduced by local hidden variables. But what is non-local in our universe need not be non-local in whatever simulates it. Just because a signal cannot reach one event from another inside our universe does not mean that no signal from the simulation of the first event can reach the simulation of the second event in a computer that simulates our universe.
    – celtschk
    Commented Mar 17, 2018 at 11:31
  • The SE.Physics citation seems mistaken; the sort of simulated-universe assessed in popularized Physics experiments isn't about any sort of simulation, but a very specific sort. A negative result is fairly meaningless. It'd be like citing a study that shows evidence against human-like aliens on Mars as proving that there aren't any sort of aliens anywhere in the universe.
    – Nat
    Commented Aug 21, 2019 at 1:04

It is impossible for us to find evidence that we are living in a simulation. All computers that can perform more than a very minimal set of operations are universal computers. A universal computer can simulate any physical system and in particular can simulate any other computer, see:


As a result, there is no way for a person in a simulation to know anything about the hardware he is running on, or even whether he is in a simulation. The laws of physics are incompatible with you knowing that you are in a simulation.

Bostrom's probability arguments are pure handwaving. A probability can only be calculated with an explanation specifying how the probabilities are relevant to the laws of physics


Bostrom provides no such explanation, so the simulation argument doesn't work.

  • 1
    Relevant XKCD: xkcd.com/505
    – Mark
    Commented Feb 2, 2018 at 23:09
  • "It is impossible for us to find evidence that we are living in a simulation." - are you sure? In case of simulation whatever entity is doing that may revel itself. I agree that it is impossible to disprove simulation. Commented Feb 3, 2018 at 12:02
  • 1
    Another relevant XKCD: xkcd.com/395 Commented Feb 5, 2018 at 1:51


As soon as you establish that creating a simulated universe is possible it becomes more likely that you are within a simulated one.

Imagine someone creates a simulation of a town, an exact replica. If you're a member of this town it is now a 50/50 chance that you're in a simulation vs the 'real' world. Now imagine, to compare, the person loads up a second simulation and runs the two side by side, you only have a 1 in 3 chance of being in the 'real' world.

Run this a few times and you'll find suitably complex simulations will have their own simulations. The number of simulations will vastly outnumber the number of 'real' worlds (if multiple) so your chances of being inside a simulation will always either equal or outweigh those of being in a real world.

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    This is Nick Bostrom's argument, which I listed. I find it dubious because it doesn't consider energy or information processing limitations.
    – CriglCragl
    Commented Feb 1, 2018 at 16:09
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    The far more dubious presupposition, here, is mentioned in section II of Bostrom's article: substrate independence, that "mental states can supervene on...physical substrates."
    – brianpck
    Commented Feb 1, 2018 at 17:54
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    @Lawtonfogle Given the assumptions, that's certainly possible, but you would then get an explosively exponential ([time needed to simulate 1s]^[number of nested simulations]) amount of time passing in the "real" world for every second in the "bottom" world. I don't think anyone claims the universe will exist for an infinite amount of time, so that definitely compromises the probabilistic argument based on the possibility that there are an unlimited amount of nested worlds.
    – brianpck
    Commented Feb 2, 2018 at 17:23
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    @user4894 You seem to have arbitrarily settled on an answer to The Hard Problem of consciousness. Did you prove true AI is impossible, and forget to tell tge world how?
    – CriglCragl
    Commented Feb 3, 2018 at 16:15
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    @Polygnome I was specifically talking about the members of the town when I talked about the 50/50. So, yes, if we're talking about the whole world then its 1000 vs the 7 billion but if you're just talking about a "member of this town" then you're back down to our 1000 vs 1000.
    – FreeElk
    Commented Feb 4, 2018 at 16:37

We know a lot about simulations, and how they work. Lets look for some of those artifacts in the real world.

Simulations use code, which includes various types of numbers - integers, floats etc. These all have a level of precision that they operate to, and thus a minimum positive value. If the 'real world' was in fact a simulation, we would expect to see physical parameters such as length/distance being quantised, with some minimum value.

Simulations run by advancing one 'frame' at a time, using a loop that updates all objects once, and then paints them to the screen simultaneously. If we were living in a simulation, we would expect time also to be quantised.

As well as minimum values for many parameters, there are usually maximum values in simulations. This is again related to the type of numbers used - after a certain point they will overflow. Sensible programmers put in limits on, say the size of the simulation and maximum velocity.

So, we're currently sitting on 3-4 out of 4 on the 'are we in a simulation' scale. Not looking good.

  • Exactly! We need to look not just at how we run simulations, but theoretical limits on them though, surely? If we could run evolutionary-iterative calculations on how to do simulations, we might do them very differently, and far more efficiently
    – CriglCragl
    Commented Feb 2, 2018 at 12:18
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    The universe does not "update all objects once, and then paint them to the screen simultaneously"
    – user22917
    Commented Feb 2, 2018 at 15:24
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    You seem to be assuming that it has to be a digital simulation. Why? Commented Feb 2, 2018 at 22:41
  • 1
    You haven't shown that the universe is likely to be a simulation. You've shown that, if the universe is a simulation, then it probably isn't being simulated on an analog computer. You haven't provided any evidence to distinguish a quantized universe from a universe being simulated on a digital computer.
    – Mark
    Commented Feb 2, 2018 at 23:01
  • 2
    @user22917 Could you clarify what you mean by that? No-one's arguing that we're literally appearing as images on some extrauniversal screen; but very many of the simulations we perform do have quantised time, and a quantisation of time is a pretty good way to give the illusion of continuity. Commented Feb 3, 2018 at 15:07

Suppose that what we call this reality is a simulation. Then by analogy, it is plausible that within this reality we can build machines that contain simulations. Also by analogy one can infer that it is plausible that the reality that simulates our current reality can itself be simulated. This implies that for any particular one of these 'realities', it may be simulated by one, and also simulate one (or more).

Then the question is ... where does it stop? One can infer that you can keep making simulations inside of simulations, and likewise infer a simulator for every one. In either direction it can keep going. So whether it stops above or below or keeps going forever in either direction, we are just one along that chain.

It's fun to imagine these situations, as in popular culture: The Matrix movies and derivatives, dreams within dreams, counterfactual time travel, a Minecraft world that simulates a Turing Machine that simulates a Game of Life that simulates a 3D-printer that prints off a VR-headset.

Thought can reflect on itself. That is all this is.

  • What about energy and entropy limitations? Computations involve energy costs
    – CriglCragl
    Commented Feb 1, 2018 at 20:43
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    @CriglCragl: In this universe, computations involve energy costs. :) Outside of this reality, we can't even say what we know as energy exists, much less any limitations our universe has imposed on it -- and within this reality, we could create a simulation where computations create "energy", if we wanted.
    – cHao
    Commented Feb 1, 2018 at 21:01
  • @CriglCragl What about them? Those 'costs' are taken into account by the simulation. If each level of simulation takes up costs at the higher level, then there might be a limit to the number of sub-sub-sub-simulations can be made. But then it's turtles all the way up.
    – Mitch
    Commented Feb 2, 2018 at 0:00
  • Could we? Not everything is a free variable. We think there are 20 something fundamental constants, forming a landscape, plus various points non-determinate quantum events interact with the macro scale making a further landscape (& maybe many worlds). If anyone can show a point the clock's mechanism altered, skipped etc, fair enough. But otherwise, it is logical to assume it was set running and then not interfered with.
    – CriglCragl
    Commented Feb 2, 2018 at 0:20
  • @CriglCragl Maybe your god walks away from his creation, but my gods are all over the place, messing with mortals, abducting them, like in their face. It's madhouse. So since this is all thought funhouse, anything goes, and you can't really assume one way or the other.
    – Mitch
    Commented Feb 2, 2018 at 1:00


Suppose that these simulated people are conscious (as they would be if the simulations were sufficiently fine‐grained and if a certain quite widely accepted position in the philosophy of mind is correct).

John Searle’s Chinese Room Argument (CRA) (“Minds, Brains and Programs”) provided evidence that computers running programs are not adequate to generate human understanding of language. Since we can understand language, we can conclude that we are not living in a computer simulation based on the CRA.

One can pick with confidence between the three alternatives Bostrum offered in the paper’s abstract:

This paper argues that at least one of the following propositions is true: (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 posthuman stage is when we have enough knowledge and technology to simulate humans with computers. Given CRA, there is no posthuman stage since the proposed technology is impossible. So the first alternative is true.

  • 3
    Lots of people (myself included) don't believe the CRA; I think it is worth pointing out in your answer that the CRA by no means closes the book on whether computers can be conscious. Commented Feb 3, 2018 at 15:09
  • 1
    @PatrickStevens I think it does close the book on strong AI producing conscious human understanding through programming on a Turing machine. The problem with strong AI is that it has presented a complete solution in using a Turing machine to simulate mind. It is easy to counter. The next question to ask is how far can physicalists, such as Searle, reduce consciousness to the brain (or body). Their position is too vague to counter as easily. I suspect some panpsychist approach would be necessary to describe mind such as what Chalmers proposes. However, even that might not be enough. Commented Feb 3, 2018 at 21:24
  • But you do agree that many people disagree with you, at least? I merely propose the edit "While not everyone agrees with its validity, John Searle's Chinese Room Argument…". Commented Feb 3, 2018 at 21:28
  • @PatrickStevens I have already mentioned in my answer that my conclusions are "based on the CRA" and "Given CRA". If you don't accept the CRA you may come to other conclusions. Commented Feb 3, 2018 at 23:42

I'd argue there are, at least, 3 good identifiers that we're in a digital simulation:

  1. That there are globally applicable physical laws i.e. the simulation is algorithmic
  2. That there's a limit to the granularity of the simulation and, if you probe below that granularity, the simulation would start to get a bit fuzzy
  3. There is an enormous, flaming message half way between here and Jupiter that says "Level 4"

As Meatloaf once said. Two out of three ain't bad.

  • Globally applicable = algorithmic..?
    – CriglCragl
    Commented Feb 1, 2018 at 12:31
  • @CriglCragl In the sense that the simulation is just following prescribed formulae that are applicable to everything in the simulation. Oh, and the rules appear to be reversible but they only ever move monotonically forward. Which is kind of weird unless you're in a simulation.
    – Alex
    Commented Feb 1, 2018 at 13:17
  • 7
    For (1), I fail to see the point you are making. Even if you established that an algorithmic simulation would imply universal laws (which is itself highly dubious), that is eons away from the claim that universal laws imply an algorithmic simulation. For (2), you seem to imply that a non-simulated world would have unlimited "granularity" (again, dubious), and you also don't bridge the gap between observable granularity and objective (for lack of a better word) granularity.
    – brianpck
    Commented Feb 1, 2018 at 17:47
  • @brianpck While I think the answer could express its reasoning far better, I think the logic being implied is that it would be computationally simpler for a simulation to have universally consistent laws of physics, and to have a finite granularity. While I do not consider this sufficient evidence to soundly conclude a higher likelihood of us being in a simulation, I can see the intuition/appeal: we have some reason to think (from a basis of understanding modern computing) that a simulation is likelier to be this way than not this way, while we know nothing about the odds for a non-simulation.
    – mtraceur
    Commented Feb 2, 2018 at 3:48

I am a bit surprised by the hostility to the concept of this question, given that it is a classic problem restated by nearly every serious philosopher. If your stance is, 'I don't want to think about it', fair enough. No one is making you. This thread is clearly stated as being about evidence for or against. You might have saved everyone time if you didnt want to address that.

I found this great article, that I'd say answers my question as thoroughly as it's going to be. Please consider what it has to say if you have been argueing this is a meaningless question.

"David Chalmers has argued that we should consider the 'simulation hypothesis' not as a skeptical hypothesis that threatens our having knowledge of the external world but as a metaphysical hypothesis regarding what our world is actually made of. " http://philosophycommons.typepad.com/flickers_of_freedom/2014/08/the-case-for-libertarian-compatibilism-a-brief-overview.html

The Peer-To-Peer Reality model framed here seems to me directly comparable to the Yogacara Mind-Only school's stance. The objection around nested or recursive realities can be seen as being directly addressed by Nagarjuna, as described here: https://absoluteirony.wordpress.com/2014/09/17/nagarjuna-nietzsche-rorty-and-their-strange-looping-trick/ Buddhist thought acknowledges reality is confusing, it does not throw hands up and refuse to engage. This avenue of thought looks to be a route towards recognising the sophistication of some Buddhist thinkers.


Science requires proofs. Sometimes scientific theories are built on a number of Axioms or Assumptions.

We cannot prove or disprove that we live in simulation. Though there are many so called "hints" proving that we live in simulation. There are very few "hints" that we don't live in simulation. I welcome everyone to collect more hints proving or disproving the simulation theory. When we get enough hints we can judge the probabilities of one or the other side being more likely.

Some of the hints proving that we live in simulation:

  1. Duality of light. It is both particle and wave. Scientific community didn't find any good explanations of that. This duality is very nicely fitting into simulation theory because waves are less computationaly expensive to simulate at the large scale, than simulating each individual particle. Read more on Double slit and Delayed choice experiments.

  2. Limitation of the speed of light and connection of speed and time at relativistic speeds. This makes no sense unless looked from the point of view of simulation. "Swapping","Refresh rate" and "Lagging" are well known terms in computer games. When games try to go faster than the computer hardware you get lagging, refresh rate and swapping issues. So limiting speed to certain constant makes perfect sense.

  3. Quantum Entanglement makes absolutely no sense unless looked from the prism of simulation hypothesis. Quantum entanglement is instantly connecting two quantums regardless of distance. This can be easily done in computer memory but not in the physical space.

There are many more hints listed in the book I just finished called "Answers In Simulation" by Iurii Vovchenko.

  • Maybe explain what "prism of simulation" is?
    – christo183
    Commented Aug 20, 2019 at 15:43
  • oh, sorry it is just an expression. It means "from the simulation theorie's perspective" Commented Aug 20, 2019 at 15:44

If we say "yes" to this question, its implications would confuse most people and they might say that it is nonsense. But we cannot blame them. Those who follow logical thought cannot admit that idea...there would be a discontinuity in the logical line of thought. Also, there is a possibility of misinterpretation of the words of great men who transcended the dual-state.

You might have heard that Advaita Vedanta gives very great importance to logic/reasoning.

If you say that we are living in a simulation, it implies that the original/real 'we' are living/existing somewhere else.

Also, (if the answer is "yes"), since 'we' are living in a simulation each 'I' would also be living in a simulation. [Each 'I' must be a part of 'we'.] This means, since all 'I's are always living in a simulation, nobody can come out of it (simulation) and realise the Truth or speak it out. I mean, they can't say about that permanent state without realising it. Also, then Truth realisation/liberation would always be a mirage in all aspects. But the truth is not so.

If one's duality is not ended completely he/she can say this to his followers: "'we' are not awaken".

But when his duality is ended completely he would say this to himself: "Actually not we, I didn't know that I was 'sleeping' (means: what I believed as, I was in ignorance)". Or some great men may keep mum about it. This is because they are in a so higher level that ordinary people can't understand.

A person who is not awaken can wake up. Then he has another state. But a person who is living in a simulation has no other choice--just live in simulation and die there. If all of us were living in a simulation we would have no other choice.

So, instead of confusing by 'splitting' the term jagat into 'we', 'living' etc they (those who could transcend duality ... when they speak about the Absolute Truth) denied all the plurality and said, "Brahma satyam jagan-mithya". [Brahman is real, the universe is mithya (it cannot be categorized as real or unreal)].

Since everybody's abilities are not alike, their (those great men's) advice is for self-realisation, for serving fellow beings etc. They didn't say that we are living in a simulation. By such statements (approval) people may become inactive/disappointed/gloomy because if it is true there would be no scope for realising the Truth). If such a society is created by this confusing statement, I would say that this is the ugliest face of philosophy. But we can say, we (those who didn't realise the Truth) are not awaken in the true sense. Since there is a higher level of awaken state, there is no mistake in it.

You should compare the meanings of mithya and simulation. You can see the variance if you could replace the phrase--'in a simulation' by 'mithya'.

Please google for explanations of jagan-mithya:



Maybe I am very naive, but I know I am not living in a simulation. My evidence is my free will!
I interact with other people and see that they also have free will. Therefore, I conclude that we are not living in a simulation.
I am aware of the controversy relating to free will, but from my point of view, there is no controversy.

  • You seem to be assuming consciousnesses with free will can't be simulated. Any reasoning for that? Being in a simulation doesn't mean you can't know anything, any more than if you are in a dream.
    – CriglCragl
    Commented Feb 5, 2018 at 23:04
  • 1
    You've picked a pretty flimsy concept to base your rejection on. If it is possible for any being that can observe this universe (from within or without) to know its future with certainty, then "free will" is ignorance, simply the rats' view of the maze.
    – cHao
    Commented Mar 13, 2018 at 17:35

The idea of the illusory nature of reality has been around since the beginning of humanity. Perhaps the Vedas 1100-1700 BC were the first ones who deeply pondered about it. The simulation hypothesis is just a new technological possibility to create fake realities or distort them which is no different than holding people captive in a dark cave (Plato) or blinding them(Bible).

Ordinary dreams and astral projections produced by sleep, deep meditations or psychedelics remind us of the illusory nature or reality and how persistence and consistency are its defining characteristics.

"Reality is merely an illusion, albeit a very persistent one" Albert Einstein

What evidence is there? It's all about probability. If something may happen then it will happen or it has already happened.

"There’s a ‘One in Billions’ Chance Reality Is Not a Simulation" Elon Musk.

What if we awoke from this reality into another reality? Would this new reality be "real" or just another illusion? How can we know? What if it was a simulation within a simulation? Could we have endless simulations embedded into one another?

I guess the problem with the whole simulation hypothesis thing is within the human psychology and mind. Why do we want reality to be "real"? Perhaps we are afraid of digging any deeper because we are emotionally dependent on our past, ego, physical bodies, skills, culture, social status etc. and many other impermanent things and that illusory/impermanent nature of reality confuses us and makes our ego feel threatened but it's only reminding us of what we are not as said in Buddhism.

"I knew that most people never see this reality because they attach to the material aspect of the world. Illusions of self and other fill their vision. I also realized there are those with little dust limiting their vision." Buddha

I guess the problem with the simulation hypothesis is the same problem with religion and a creator god. Sometimes when there is no proof in favour or against it's hard just to be agnostic.

  • "It's all about probability." Surely you have to reason to that, induction can't justify induction? What about unlikely or unrepeatable events?
    – CriglCragl
    Commented Aug 27, 2019 at 22:35

Categorically this question only has one correct answer:
(a) If we are living in a perfect simulation such that there is no discernible difference between the simulation and reality then by definition there is nothing telling the difference.

(b) If there is a discernible difference then discerning this difference tells this difference. Instead of hypothesizing every possible way that this difference could be discerned let's cut to the chase. The difference that proves that we are living in a simulation is that physically manifest reality can be changed by thoughts kept silently in the mind.

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