17 ms·

Your yearly dose of is-the-universe-a-simulation

251 points by evanb 10y ago

FrankyHollywood 10y ago
You only need to simulate one mind actually, it's all a dream :) https://en.m.wikipedia.org/wiki/Solipsism https://en.m.wikipedia.org/wiki/Solipsism
powera 10y ago
I'm yet to hear a simulation theory with more explanatory power than the much simpler theory of "God did it". Most of the claims are variants of "but computers, so science", which is not an argument at all.
- codebolt 10y ago
  To me, even if we ignore the God debate, there are some big problems with theories like these because they irreverently presuppose that everything including the human mind can be reduced to mechanical/mathematical principles. This ignores things like the problem of qualia (which I'm subjectively convinced is real), and the Penrose-Lucas argument for why there is a non-computational component to human consciousness.
  - TekMol 10y ago
    I don't experience any qualia. And I don't believe you that you do. Do you have any arguments that could convince me to believe you?
    - rectangletangle 10y ago
      Well that's because you're a zombie.
    - SomeStupidPoint 10y ago
      Why do I need to convince you I experience qualia? You're welcome to propose models that omit it, but they'll fail basic logic to me: they fail to explain the only experiment Im absolutely sure of the results of and which is continually running while I'm existing. Im less sure gravity exists than that qualia does for me. It's entirely possible no one else does, or that they experience a different qualia. It's also not possible to prove that you do to others. I see no point in trying to convince non-qualia-experiencing entities that I experience it, because they fundamentally don't have experiences and I don't think it's possible to bridge that gap.
      - simonh 10y ago
        To me that, and 'I think therefore I am' are just I'm a special snowflake arguments. I take the simulated Intelligence argument the same way. Suppose you could create a simulation of an intelligence that was indistinguishable from a real one? Well then, you'd have created an artificial intelligence. If such a thing reported that it experienced qualia I'd have no reason to doubt it. Edit: to put it differently. Suppose I built a model of a Formula 1 engine. I used different materials at a different scale and used a different fuel, but to precise tolerances so that it could actually run. Would it be a Formula 1 engine? No. Would it be an internal combustion engine? Of course, nobody would doubt it.
        SomeStupidPoint 10y ago
        I think you're wrong about them being "special snowflake" arguments, and likely miss the point of them. Those arguments are very low-level in the intellectual stack, and can only address matters of subjective self because what they seek to establish or discuss is more fundamental than concepts like objectivity. (Well, cogito ergo sum is establishing an objective fact from a subjective one to give a basis for later objective discovery.) Any full accounting of the world must explain the mechanism by which I experience it, or it hasn't explained the only part of the world Im sure exists (my experience of it), and hence can't be a full accounting. You can have a very good predictive model for features of that experience, but neglecting that experience -- qualia -- is leaving a major thing unexplained. Similarly, cogito ergo sum is likely better phrased as "computation ergo existence" -- the process of doubting is a form of doing something, and so something must exist which is doing that (or is that process). This establishes that there must be some sort of existence, even if it's just a brain in a jar, random memory from quantum noise, etc. You can't doubt there's an existence, because the very act of doubting is proof of existing. You can only doubt the form of it. I also disagree that we'd have no reason to doubt the claim, but I agree we have no a prior reason to reject it. Your edit also makes a major assumption: that we know what causes qualia (our brain structure). That's the very thing being debated, so you're just begging the question.
        simonh 10y ago
    - codebolt 10y ago
      All I know is that I experience qualia. And I believe that you and all other humans do too, but perhaps some people just aren't aware of it in the same way as I am. As someone who has a pretty good grasp of both physics and computer science, I am personally convinced that there is no way a circuit board could give rise to the same type of subjective experience of qualia that I am experiencing. I know that's not really an argument, but just because I can't express my conviction in clearer terms doesn't make it any less real to me.
  - michaelmrose 10y ago
    The universe is composed of particles, waves, or strings or whatever you prefer math describes each constituent part so why does math not describe the whole?
    - codebolt 10y ago
      Like I said, I don't accept this physicalist assertion, because it ignores the problem of qualia and the Penrose-Lucas argument (which demonstrates quite clearly how the human mind is able to violate Gödels incompleteness theorems, and therefore is not equivalent to any purely computational system).
      - Sunset 10y ago
        >the human mind is able to violate Gödels incompleteness theorems This is why philosophy majors should lay off the math and biology arguments.
        codebolt 10y ago
        I was never a phil major. On the contrary, I have degrees in physics and computer science. My introduction to this idea came from reading the books of Roger Penrose, a man I have a great deal of intellectual respect for.
      - gjm11 10y ago
        No, the Penrose-Lucas argument does not demonstrate any such thing quite clearly. In fact, the argument was refuted in print before Lucas ever published it, in a nice paper called "Minds and machines" by Hilary Putnam. Exactly where it fails depends on exactly how it's stated, but here's a sketch: Goedel proved that a formal system powerful enough to talk about mathematics either is inconsistent or else cannot prove its own consistency. Lucas and his followers claim that human mathematicians have no such limits; presented with such a system they can just see that it's consistent. In Lucas's version we look at some particular candidate system that might implement a human being, and just see it's consistent. In Penrose's version we look at mathematics as a whole and just know it's consistent. But this is all nonsense. Real human mathematicians don't look at the sort of system that might implement a human being (still less, the totality of all mathematicians working together) and "just see" it's consistent. They don't even look at the nice streamlined formal systems they've made specifically for doing formalized mathematics in and "just see" that. Frege's system was inconsistent and he didn't notice after writing two volumes on it. (Russell famously pointed out an inconsistency.) Quine's ML was inconsistent and he didn't notice until Wang pointed it out. For all we know there might be some inconsistency lurking in ZF; it seems like a very good guess that there isn't, but that's all. And, I repeat, those are highly streamlined systems that don't attempt to do anything nearly so complicated as describing the complete behaviour of an actual mathematician's mind. We do sometimes attempt to study computer hardware and software -- systems a bit more like actual human minds, but still orders of magnitude simpler -- using formal methods. Sometimes we try to prove them correct. These proofs are also often wrong, which is why hardware and software have bugs. (In some cases we're pretty confident about relatively large systems; guess what?, the correctness proofs for those are done by computer and there's no "just seeing" about them.) The idea that a human being could look at a formal system representing the entirety of what their brain does and "just know" that it's consistent is not just wrong, it's one of the wrongest things any otherwise intelligent human being has ever suggested. But that is (part of) what it would take to show that the formal system didn't really model them perfectly. This is far from being the only major error in the Lucas-Penrose argument, but it's the worst one.
  - ravitation 10y ago
    The fact that it ignores two things that are controversial at best seems to not really be a problem... Qualia's existence is more or less unprovable given its definition, and there are numerous objections to the Penrose-Lucas argument. Using either as a basis for an argument is essentially the same as basing an argument in faith.
    - visarga 10y ago
      In my opinion, qualia is just a word that stands in for agent-centric perception. For a reinforcement learning agent (such as human, animal, robot or AlphaGo) qualia is the combined effect of perception and value function. I think Chalmers tries to introduce a kind of dualism here - he's saying that human experience is something special, unlike other mechanical processes (which can only be mere p-zombies). I don't think it is a good idea to turn to dualism because it has been proven flawed and leads to philosophical conundrums. I think current day philosophy doesn't properly appreciate the insights coming from AI. We have seen AI give amazing results in perception : images, sounds, video - it's no mystery any more. You just put 100 layers deep convolutional nets to solve the problem from data. Philosophers still talk like we don't know how perception works, or that it results in ontologically special qualia. Another very important AI insight that is being ignored by contemporary philosophers is Reinforcement Learning. We have made great advances in intelligent behavior, and RL concepts (agent, environment, reward, and learning) are better suited for explaining human consciousness than traditional concepts such as free will, qualia and Chinese Rooms. Wittgenstein's concept of language games is apparent in reinforcement learning. There has been a recent paper about agents evolving a new language by trying to solve a problem together. Also, language philosophy should take a look at word embeddings. Maybe philosophy needs more grounding in AI.
- TekMol 10y ago
  Could you define "explanatory" in this context? When you say "God did it" - how did he do it? The simulation idea often involves concepts like computers and turing completeness. Not sure those meet your idea of "explanatory" here. But they explain how it could be done. While I never saw an explanation how God did it.
- sebleon 10y ago
  *disclaimer: no explanatory power, just food for thought 'cogito, ergo sum' We could very well be 'real' consciousnesses being fed artificial sensory data. While we would exist outside the simulation, our perception of objective reality might be fake.
  - bambax 10y ago
    That's the Matrix, exactly. But they have flip phones there.
    - sebleon 10y ago
      Ha, the flip phones are key. They must have algorithmically calculated that the 90s were the optimum time to live a false life. I wonder why the machines made people live boring lives - seems like a great way to get them to wonder "is there more to life than this?"
- RyanCavanaugh 10y ago
  Let's say that for a given set of physical laws, you get some "computational power" P, which characterizes how hard it is do to computation using those laws. You could imagine a universe with lower P than ours, where light was much slower, or the only workable transistor had a switching time on the order of seconds. Given a universe with computational power P, you can simulate a "universe" of something like P * 10^-100. For example, a Minecraft world is a universe with different physical laws, in which you could perform even slower and worse simulations, and you can make "turtles all the way down" at lower and lower P. The claim that our universe is not simulated, then, is nearly equal to the claim that the physical laws we have is the absolute highest P that could ever exist. Since we know we can simulate universes of much lower P than ours, we ought to have very good reason to assert that there is no universe of much higher P than ours. Given a finite speed of light in our universe, yet nonlocal effects (Bell inequalities) which appear to take instantaneous effect, we could perhaps fathom a universe of higher P created by having a method of communication which occurred instantaneously. Add to this more dimensions in time and space, etc... literally nothing is off the table for a "smarter" universe to be conceived of, because the containing universe's physical laws need bear no resemblance to our own. Barring a literal divine intervention, though, it's all completely unfalsifiable, but I think it's more nuanced than "God did it".
  - teraflop 10y ago
    I think the Minecraft analogy is illustrative. In Minecraft, you can use redstone circuits to construct logic gates, and use those gates to build computational devices that are Turing-complete, in theory. But it's not possible to scale such devices up arbitrarily; you can build a simple CPU, but nothing that even approaches being able to run a nested copy of Minecraft. There are hard upper bounds on the amount of data that the simulation can cope with at once. (You can imagine patching Minecraft to allow keeping more chunks loaded at once, but you can't scale it up by very many orders of magnitude before you end up with something that can't run efficiently on any hardware that physically exists.) Similarly, as Scott Aaronson describes in the article we're discussing, it's likely that there are finite bounds on how much computation can possibly be done before the heat death of our own universe. So it's fair to be skeptical that a tower of "turtles all the way down" could ever possibly exist, at least on a universal scale. If there's no tall hierarchy, then the anthropic argument (which says that we're unlikely to be at the top) breaks down. You can certainly hypothesize higher levels which have infinitely fast communication, or other kinds of special properties that make deep simulations more feasible. (Greg Egan proposed one such cosmology in his novel Permutation City.) But you don't get to assume that and still use simulations within our own universe as examples, because you're talking about something entirely different.
snowwrestler 10y ago
Here's what I wrote in a comment here last year about the Bostrom simulation argument specifically: The simulation argument, going back to Bostrom, relies on two flaws. 1) It leverages our optimism to corrupt our understanding of statistics and logic. It essentially says that if you think humanity doesn't destroy itself, then our descendants will probably try to simulate us. But of course if you just take a statistical view of the potential future ordered states of the universe, there are FAR more potential future states in which we don't exist, than states in which we do. The chances we are living in a simulation now are equally as small. 2) Bostrom hypothesizes that our descendants will try to simulate us. But it is impossible to completely simulate a system from inside that system--that's basic thermodynamics. So simulation proponents argue that our simulated reality is running in a more complex universe than we experience. But if that is the case, then the beings running the simulation are not our descendants! They're the descendants of whatever more complex beings came before them. Once again the central logic of the argument fails.
- baddox 10y ago
  > But it is impossible to completely simulate a system from inside that system--that's basic thermodynamics I haven't heard quite that argument before. Couldn't it just be simulated slower than real-time? Or is memory the issue?
  - fsloth 10y ago
    "I haven't heard quite that argument before. Couldn't it just be simulated slower than real-time? Or is memory the issue?" The "real time" in simulation is not affected by how long a single time step takes to evaluate in the real world. https://xkcd.com/505/ https://xkcd.com/505/
  - psyc 10y ago
    Regarding "Basic Thermo", everything we 'know', we subjectively acquired over a tiny period of time, through a game of telephone that refers to the current universe. We're really in no position to comment, in absolutes, on the nature of the parent universes.
  - 10y ago
AnonNo15 10y ago
I had thought about this idea and came to the conclusion that if the full universe simulation is ever possible, it is highly likely that we are living in one right now. And the only way to prove it is possible, is to attempt to simulate one.
- baddox 10y ago
  Your first sentence is precisely Bostrom's argument, which is pretty much the canonical argument for the simulation hypothesis.
  - visarga 10y ago
    And thus we open the door again for Intelligent Design. If we live in a simulation, then we could be the creation of an intelligent and powerful designer.
    - AnonNo15 10y ago
      The point about unfalsifiability is still valid. Even if we can simulate sentient life we still can't prove we ourselves are simulated or not.
deleted 10y ago
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moomin 10y ago
Until someone demonstrates a jailbreak, I'm going to regard this hypothesis as moot.
- deleted 10y ago
  [deleted]
- ftlio 10y ago
  Timothy Leary is a double entendre here...
planetjones 10y ago
But couldn't our universe be being simulated by a species far more advanced and discrete to anything the human race has ever encountered? How do we know that another form of life doesn't find everything that we find super complex extremely trivial ?
- moxious 10y ago
  It could be the case that we are being simulated by a far superior alien species. It could also be that invisible pink unicorns in the 15th dimension control all of our thoughts and only want us to believe this. Without being tongue in cheek, I'll observe that the empirical evidence for both of these ideas is equal in quantity. We don't know for sure that these things aren't true. But to ask that question is to inappropriately shift the burden of proof away from the claimer. Whoever claims something (we live in a simulation) should put up the evidence or get out. It's not up to bystanders to disprove the assertion. Connecting this to current events, even the president of the USA doesn't get to make baseless claims that his predecessor wiretapped him and get away with shifting the burden of proof to the FBI to prove he wasn't. This "reversal of burden of proof" is a classic but invalid way to make a point.
  - sillysaurus3 10y ago
    There are many questions in life that are interesting to consider, independent of whether they're falsifiable. It tends to get boring to consider only questions that can be experimentally proven, though different people have different interests. Questions about society and human nature are worth considering, for example, but it's difficult to do controlled experiments. There's some truth to "watch out for wishful thinking," but usually conversations about the actual topic are more interesting.
    - Swizec 10y ago
      The part where "is this a simulation" becomes an uninteresting question is when you ask "Does it matter?". Would answering the question of whether we're in a simulation have any impact on your behavior, thoughts, and actions? Probably not. So what does it matter? My high school physics teacher once said that, if we ever find something that is outside the universe, then we will obviously be smart enough to call that the universe also. Because "universe" is a definition that means "everything". Similarly, if we ever find a reality beyond reality, we'll just call it reality. Because that's how it's defined. It means "everything". Or put another way: Of course we live in a simulation. Your experience of the world is just an emergent property of how your senses and neural system interact. There's no real reality. You're already trapped in a dark box doing fly-by-instruments using signals processing to interpret what your nervous system is detecting. Is that not already a simulation anyway? Maybe not. Maybe it depends on how you define "you". Fundamentally, would knowing that you're in a simulation change anything?
leni536 10y ago
The statement "we live in a simulation" is not falsifiable. For me this question is simply not interesting.
- intjk 10y ago
  At the end of the article, Scott essentially says the same thing, but emphasizing the other side of the coin: > [...] the question of whether the universe “really” “is” a simulation has barely come up. Why would it, when there are so many more fruitful things to ask?
  - inopinatus 10y ago
    I always felt that the point of asking this question was not the answer itself, but that theorising how it might be implemented could lead to hacking the sandbox. IANATP but I've read, for example, that violating Lorentz invariance is an active research area.
    - XorNot 10y ago
      Or looking for aliasing from a lattice QCD simulation in cosmic microwave background...
- fsloth 10y ago
  That's my take on it too. The history of physics has shown, though, that it pays in interesting ways to go through every crazy idea until it's actually refuted or understood to be wrong.
  - Cookingboy 10y ago
    But this is not physics, or science, unless you can have falsifiable claims. Otherwise it's just philosophy or metaphysics, which does not warrant a scientific discussion.
- bambax 10y ago
  Also, it doesn't explain anything, and esp. nothing about the simulators: are they themselves simulated (and so it's turtles all the way down, again) or are they not? And if not, why not, and who are they? etc.
pilingual 10y ago
It's amusing that the point of the blog post was how refreshing it was to be at the Stanford conference with bright minds talking about stimulating new topics; yet the comments here on HN continue to discuss the tired topic.
- tempodox 10y ago
  You couldn't simulate that if you tried.
z3t4 10y ago
I've been thinking about distributed databases lately and how such a system should be designed. How does nature do it ... ? (quantum mechanics)
polotics 10y ago
Contributing to the debate: How frequently do you fire up sim-city / how frequently do you fix up lunch?
Myrmornis 10y ago
Can someone explain the first bit of the last sentence? > if our world is a simulation, then whoever is simulating it seems to have a clear preference for the 2-norm over the 1-norm Is it basically saying that space looks Euclidean at a range of scales and Pythagoras crops up everywhere or is it saying something else / more sophisticated? What would the Universe look like if its creator favored a 1-norm?
- gjm11 10y ago
  I think he's referring less to the geometry of space(-time) and more to the structure of quantum mechanics. Classical probabilities are positive real numbers that add up to 1. (The 1-norm of the vector of probabilities is 1.) Quantum ampltiudes are complex numbers whose squared absolute values add up to 1. (The 2-norm of the vector of amplitudes is 1.) A universe made by someone who preferred 1-norms would more likely be classical rather than quantum. For more on this from the author of the linked blogpost, see here: http://www.scottaaronson.com/democritus/lec9.html http://www.scottaaronson.com/democritus/lec9.html or the corresponding bit in his excellent book "Quantum computing since Democritus".
  - Myrmornis 10y ago
    Thanks! That was a really helpful reply. Started reading the Aaronson intro to QM you linked and it does seem like a very direct and understandable approach to the subject.
tazjin 10y ago
I experienced a series of extremely unlikely coincidences recently and one of my first thoughts was that if The Sims was a sufficiently advanced game I'd be doing those sorts of things to the characters.
- lwhalen 10y ago
  Do tell!
- egeozcan 10y ago
  I used to take writing lessons and the teacher always said that the coincidences only happen in real life, not in stories because that wouldn't be realistic.
js8 10y ago
I don't understand why is simulation even necessary. Simulation argument says that our universe and consciousness is pretty much just some sort of mathematical structure, that is being manipulated according to some simple laws as it evolves through what we call time. But then, isn't the only requirement for beings inside this structure to perceive it as such that the structure exists? Do you need to really physically manipulate it? To put it differently, what if the designers of the simulation could come up with some theorem that would let them correctly skip hundreds of years of simulating something. Would beings in those hundreds of years still existed, even though it wasn't actually executed? What if they just calculated the final answer? Would we then exist? So, to me, either this is nonsense, and we are not in simulation, or, any kind of mathematical structure that can possibly exist somehow "exists" and no "creator" is needed. But neither of those two options is a good argument for existence of simulation creator.
- pka 10y ago
  That's intersting. If the universe could be simulated, you could, in theory, run that simulation on a (very large) piece of paper by hand. Running the simulation would then be equivalent to calculating some numbers and writing them down. Basically, if I wrote down the correct sequence of numbers, I could simulate you. But is calculating those numbers actually necessary? Is it enough to just have the result of that computation without performing the actual steps to obtain it? If yes, then a random number generator would be all that is needed to simulate our (and infinitely many other) universes. And if that's the case, maybe it's not such a big leap to imagine that the mere existence of the physical laws as an abstract concept is enough to give rise to a simulation?
  - carry_bit 10y ago
    > And if that's the case, maybe it's not such a big leap to imagine that the mere existence of the physical laws as an abstract concept is enough to give rise to a simulation? Calculating it just provides a window into the simulation; it still exists (in an abstract mathematical sense) even if you're not looking.
  - xinyhn 10y ago
Insanity 10y ago
I am not sure what to make of the whole universe-is-a-simulation argument. The problem is that, this is as far as I know, not an hypothesis we could ever hope to prove. Not any more than we can proof that a diety exists outside of this world. I highly doubt that there is a higher creature, whether that would be a God of some kind, or a whole civilization outside of our universe that somehow simulates us. But let's for entertainment suppose that we are in fact a simulation. Would that not immediatly raise the question "why"? If we are a simulation I would really like to know the reason for being simulated. What do they hope to reach with simulating a life like ours? I fear we could never find a satisfactory answer to these questions. I also agree with the statement that this brings us back to a more mythological explanation of the universe and life around us. It'd make more sense to try and explain our universe without that hypothesis to me. Another argument that I'd like to raise against the universe-simulation hypothesis is the following. Humans like to see the world around them in terms of the technology that, at that moment, is considered modern and which they like. For example, Freud compared the human brain to the steam engine, which at that point was modern technology. Today, we compare the brain to a computer, and we even go as far as to consider the whole universe might be similated in one. Maybe just because that is what we consider 'modern' at the moment? In 1000 years from now, humans might think it's silly to think of the brain as a computer and rather think of it in terms of technology X, and the universe is technology Y.
- glaberficken 10y ago
  > But let's for entertainment suppose that we are in fact a simulation. Would that not immediatly raise the question "why"? If we are a simulation I would really like to know the reason for being simulated. What do they hope to reach with simulating a life like ours? They would hope to reach the exact same answers that we do when we simulate things inside our own computers. To understand our own reality better. Imagine for a second you are that "external" (to us) God or civilization. You simulate this whole other universe (ours) to find out if it's possible that your own reality is a simulation.
- simonh 10y ago
  I think it's interesting to speculate what the simulation argument means for religion. The existence of a simulation creator doesn't actually disprove the existence of an ultimate god, after all the beings running the simulation might have a divine creator, so it just pushes the question up a level. But it does pose a problem for imminent religions that believe that god intervenes in the world to cause miracles. How do you know that any given miracle was caused by the ultimate god and not the simulation sysadmins editing the simulation? The whole question of miracles and divine providence becomes deeply problematic.
TelmoMenezes 10y ago
Something that most people never consider in these discussions: If you accept the hypothesis that mind is generated by a computation, and that this computation is finite, then the same computation that produces "you" can be performed in different places and at different times. The same computation can be performed inside a simulation, inside a simulation inside a simulation and so on. Whatever environment around you can be included in this computation. As long as the computation is finite the larger and/or more temporally extended the universe is, the higher the probability that the computation that is generating this current moment for you is being executed more than once. If the universe is infinite in some sense, this probability converges to 1. And yet you would have no way of knowing that this is happening. So I claim that, if you assume that mind is generated by a computation, then then question of wether we are in a simulation or not can be replied with "both" or "it doesn't matter".
- GuiA 10y ago
  Except that your mind is not an isolatable computation - it is influenced by your body, which is in turn influenced by its immediate environment, in turn influenced by the rest of the universe in an ever expanding nested fashion. So if you want to simulate yourself, you have to simulate the universe.
  - deleted 10y ago
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  - Ntrails 10y ago
    > So if you want to simulate yourself, you have to simulate the universe. This doesn't gel with me. I go back to brain in a jar stuff - I'm just streaming packets of data from nerves and processing them. Whether the "body" I'm responding to is real is pretty hard to guarentee.
    - GuiA 10y ago
      There's evidence that your brain is influenced by e.g. certain chemicals in your bloodstream produced by gut bacteria. https://www.theatlantic.com/health/archive/2015/06/gut-bacteria-on-the-brain/395918/ https://www.theatlantic.com/health/archive/2015/06/gut-bacte... So the brain in a jar model where the only interface with the real world is through nerves is most probably wrong; now your jar also needs a stomach with a fully developed microbial ecosystem. And that's just one recent mechanism that was investigated; there are probably many others.
Aeolun 10y ago
I recently read a short story about this exact subject: https://qntm.org/responsibility https://qntm.org/responsibility I think it quite accurately represents the mind-fuck that this causes.
- jfries 10y ago
  Wow that's quite a thought experiment. Fun twist at the end, I wonder how society would react to this realization.
julianpye 10y ago
Regarding AI and God and religion - here is a blog post that I wrote that suggests that being in a simulation actually increases our chances for a religious afterlife. https://medium.com/@photodiary/implementing-religion-in-ai-life-simulations-45e6e293b8aa#.giqw4s25n https://medium.com/@photodiary/implementing-religion-in-ai-l...
- sillysaurus3 10y ago
  This runs into the question of whether you're a single person. https://www.youtube.com/watch?v=nQHBAdShgYI https://www.youtube.com/watch?v=nQHBAdShgYI https://www.youtube.com/watch?v=qjfaoe847qQ https://www.youtube.com/watch?v=qjfaoe847qQ If you transplant half your brain into another body, and both of you wake up, which one is you? If you start swapping your atoms one by one with someone else, and neither of you die, at what point do you become the other person? Unfortunately questions like that are necessary in order to address the idea of a simulation afterlife. If our bodies are literally who we are, and our bodies disperse, it may not make sense to say that we can still be simulated after our bodies disappear.
- jonathanstrange 10y ago
  That's a non-sequitur you have there, because you do not even attempt to explain why there should be a case distinction. To be fair, even Nick Bostrom's original simulation argument is also based on several fairly unfounded and not very plausible assumptions (e.g. what extremely advanced societies would do). Much of the debate seems to be based on speculation.
  - julianpye 10y ago
    Well, my blog-post is half-serious. The bigger question from it would be why the hell the Universe would be implemented in Java :)
    - evanb 10y ago
      Honestly, we hacked most of it together with perl. https://www.xkcd.com/224/ https://www.xkcd.com/224/
KCFforecast 10y ago
How to solve any problem quickly: Program your computer to solve a problem in a million years time, then go for a travel at the speed of light, come back to your home and consult the solution of your problem, you have been traveling only a few days but your computer has been doing computation a million of years, so you now have the solution, a quick one. Just alter that system to use the relative time to have computer working millions of years to solve problems for you and you can have the solution in days. Call it photon computation to give the system a name.
- StavrosK 10y ago
  That's not "quickly". That's your consciousness slowing down to a rate of one day per million years.
  - KCFforecast 10y ago
    You don't solve the problem by yourself, that problem is solved for you on system A, in system A a million years have lapsed but in your life only a few days have passed.
    - StavrosK 10y ago
      I know, but that's not "quickly". It's just that time passes slowly for you. "Quickly" would be if my friends and family were still alive and the world were recognizable (and there) by the time I got back.
      - KCFforecast 10y ago
        Try this version instead: There is a rocket to be launched for people to upload problems to solve, the rocket travels in such a way that it is able to solve all the problems and come back to tell people the solution. The way it solves the problem is by orbiting around a tiny planet full of computers devoted to compute the problems they are communicated of. The problem seems to be how to locate the observers. Edited: time dilation and computation: https://arxiv.org/pdf/0907.1579.pdf https://arxiv.org/pdf/0907.1579.pdf
tempodox 10y ago
Eventually, it comes down to the question whether any self-respecting non-simulated universe would actually tolerate that amount of the-universe-is-a-simulation braincrackery. My simulation of Occam is turning in his grave.
mrleiter 10y ago
Immanuel Kant foresaw all this. In his seminal work "Critique of pure reason" he argues that our pure reason, as opposed to the pure mind, always tries to look for the absolute, the absolute of all conditionals. This leads our reason to look beyond empirically observable objects. Those objects that have their origin only in pure reason is what he calls "ideas". Those ideas can be separated into three categories, namely psychologia rationalis (Soul), cosmologia rationalis (World) and theologie transcendentaus (God, or Being of all Beings). Ideas can never be proven or falsified for that matter. But they have their use: be a guideline for our living. This is where Kant's famous practical philosophy stems from.
- Aqueous 10y ago
  What Kant said about the world of appearances (phenomena) and the world of objects in themselves (noumena) is also interesting especially for this discussion. He said we can know that there is a noumenal reality - a reality completely independent of our perception - but we just can't say anything meaningful about its character at all, since we can only perceive the world of appearances, or reality as it is subject to the conditions of our perception. For Kant it might not be meaningful at all to say that our 'world of appearances' is actually a simulation, for that would be implying something about the character of reality-in-itself that we simply cannot apprehend. As an aside, his proof that a world of objects-in-themselves exists at all is incredibly interesting and provides what in my view has been one of the only compelling answers to the radical skepticism of Hume (the idea that we cannot prove the existence of an external world).
  - CuriouslyC 10y ago
    The problem with Kant's view of an objective outside world is that it is to some degree demonstrably false. Quantum physics shows us that the observed and the observer constitute a system, and the nature of the observer influences the properties of that system as a whole. That influence might be small enough on very large scales to call the observed to some degree "objective" but we don't know that for sure.
    - deleted 10y ago
yk 10y ago
Putnam has a very nice argument in his Brains in a vat paper. [1] Basically he argues that a brain in a box lacks any causal connection to the box, the brain does never learn any information about the box. The idea "I am a brain in a box" lacks a reference and any reasoning about it is at best a lucky guess, even if true. The issue is the similar, but more fundamental, as me claiming "you have a misplaced comma in the second sentence of your next email." That may or may not be true, but if it is true it is certainly not based on sound reasoning. [1] http://ieas.unideb.hu/admin/file_2908.pdf http://ieas.unideb.hu/admin/file_2908.pdf
wallace_f 10y ago
The author writes about exceptional attendees at the conference: >...from Lenny Susskind and Don Page and [and..., and..., and...] This is what I don't like about academia. It's equivalent to "shout outs" you see 12-year-olds do in Call of Duty tournament games. I know everyone knows academia is filled with politics, but if scientists are going to circle jerk, please jerk on ideas, not each other.
deleted 10y ago
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Geee 10y ago
My hypothesis is that we are in a natural simulation, i.e. simulated by a computer which evolved by itself. Or layers of simulations. The "base universe" should be the simplest possible universe that is very simple, but capable of evolving the first simulation, which is more complex universe.
wnkrshm 10y ago
I don't understand how rejecting that the state of the universe is fundamentally computable is the same as rejecting the Church-Turing Thesis. Rejecting the computability of the universe's state is more fundamental: It rejects one of the assumptions of the Church-Turing Thesis, namely that there is a function to compute at all.
amelius 10y ago
My personal favorite (untested) theory is that the universe does not exist at all in reality, but only in an abstract way through a rewrite system that combines "nothingness with nothingness" ad infinitum [1, 2] [1] http://www.worldscientific.com/worldscibooks/10.1142/6544 http://www.worldscientific.com/worldscibooks/10.1142/6544 [2] http://www.youtube.com/watch?v=W2XdhzCORbo http://www.youtube.com/watch?v=W2XdhzCORbo
umanwizard 10y ago
Casually using phrases like "the absolute of all conditionals" as though anyone is supposed to understand what that means makes your whole post sound like gibberish. This is why philosophy is the butt of jokes.
- bgilroy26 10y ago
  We have the Internet. If the parent commenter thought a more digestible summary or paraphrase of "the absolute of all conditionals" would have been helpful, they would have written it that way. If you're frustrated that it's opaque, and you care about understand the chance to do so is as near as googling "Kant absolute of all conditionals". If you don't care about understanding, why complain?
  - consz 10y ago
    I spent about a minute looking at the results for "Kant absolute of all conditionals" on google, that phrase doesn't have any close hits, I think its fair to describe this phrase as non-trivial to understand just through googling, so I think your snark is unwarranted.
    - sesqu 10y ago
      I spent a minute looking at the results of that phrase on ddg, and got a hit on the book in question. While it's not a direct quote, a search of the book finds this line: > On the one hand: We set limits to reason, preventing it from leaving the guiding-thread of empirical conditions and straying into the transcendent and explaining things in terms that can’t be cashed out empirically. And also, on the other hand (this being my present point): We set limits to the law of the purely empirical use of the understanding, preventing it from making decisions about the possibility of things in general—i.e. of things of any sort—and ruling that intelligible things are not merely incapable of explaining appearances but are impossible. I assume that's what OP meant.
  - umanwizard 10y ago
    Are you trolling or something? I did google it and there were no relevant results. Putting "absolute of all conditionals" into Google gives a bunch of stuff about absolute convergence in calculus without quotes, and no results at all with quotes.
jmcdiesel 10y ago
I think its a great question to ponder on, and I think anyone making a claim in either direction is wrong... To claim it is a simulation is just overreaching, because there is no real evidence. To claim its not, that its not possible, is hubris - just because we can't simulate it now doesn't mean in a million years a society following ours wouldn't be able to, and if you say even a society in a billion years would be able to, then you're saying its possible, and if its possible, than you can't say we're not. I love unanswerable questions. Especially with a little sativa in my bowl. :)
draw_down 10y ago
I'm reminded of when I was in school, and took western philosophy to try to get some help with how to think about life and the world. Instead what I got was a bunch of, like, Descartes staring at a candle and trying to figure out if it's real. My thought then and now has been, it doesn't matter. This existence has certain rules to it. Drink poison and you die, hurt people and go to jail. It's up to us to figure out how to navigate that for a time, and that's all we get. As far as we know. Even if you knew what was outside what we call reality, even if you knew the form of the simulation- what could be done with that information? I wonder if this sort of thinking is ultimately propelled by a fear of death or some other impetus compelling people to deny that reality is what it really is. Maybe it's somehow comforting to think that your loved ones don't really die and neither do you, suffering isn't real, it's just qubits being shuffled around in a formal game that lacks higher meaning.
6stringmerc 10y ago
I'm nurturing a thought that the experience of Human Life is much more akin to a biological radio antennae picking up on a cosmic "living" code base being broadcast somewhere out there which encompasses the entire known universe. That's where the postulation stops and I just go with "turtles all the way down" after that.
akssri 10y ago
I'm a string in X^*, and the universe is a real number.
ouid 10y ago
This question is so fundamentally bullshit that a new, stronger form of the word fundamental is required to truly describe it. Of course the universe is a simulation. There are either more fundamental processes occurring which explain the behavior of our observations, or it is the identity simulation. Newtonian laws are simulated with quantum laws, atoms are simulated with quarks, time is simulated by statistical relationships, and chemical interactions within the rules of the other abstractions are sufficient to simulate our observations. If you believe that this question is about whether or not there is some anthropomorphic supervisor of the simulation, then THAT is the hypothesis you should be putting forward, not that the universe is a simulation, which is meaningless.
mannykannot 10y ago
Maybe I am just not following, but the arguments of Sabine Hossenfelder, Scott Aaronson, and of a great many posts here seem to assume that reality is something like what we (or should I say I?) experience. If our (my) universe is a simulation, nothing we (I) perceive about it is trustworthy, and that applies as much to odds as to absolutes. Has there been any argument against the possibility that does not either beg the question by tacitly assuming that our perceptions inform us about the ultimate reality, or alternatively squeeze the essence of the problem into a tight little knot and thereafter avoid dealing with it directly, as I think Kant (among others) did? I do not actually think I am a simulation, but I cannot argue against it.

251 points by evanb 10y ago

You only need to simulate one mind actually, it's all a dream :) https://en.m.wikipedia.org/wiki/Solipsism https://en.m.wikipedia.org/wiki/Solipsism

powera 10y ago

I'm yet to hear a simulation theory with more explanatory power than the much simpler theory of "God did it". Most of the claims are variants of "but computers, so science", which is not an argument at all.

codebolt 10y ago
To me, even if we ignore the God debate, there are some big problems with theories like these because they irreverently presuppose that everything including the human mind can be reduced to mechanical/mathematical principles. This ignores things like the problem of qualia (which I'm subjectively convinced is real), and the Penrose-Lucas argument for why there is a non-computational component to human consciousness.
- TekMol 10y ago
  I don't experience any qualia. And I don't believe you that you do. Do you have any arguments that could convince me to believe you?
  - rectangletangle 10y ago
    Well that's because you're a zombie.
  - SomeStupidPoint 10y ago
    Why do I need to convince you I experience qualia? You're welcome to propose models that omit it, but they'll fail basic logic to me: they fail to explain the only experiment Im absolutely sure of the results of and which is continually running while I'm existing. Im less sure gravity exists than that qualia does for me. It's entirely possible no one else does, or that they experience a different qualia. It's also not possible to prove that you do to others. I see no point in trying to convince non-qualia-experiencing entities that I experience it, because they fundamentally don't have experiences and I don't think it's possible to bridge that gap.
    - simonh 10y ago
      To me that, and 'I think therefore I am' are just I'm a special snowflake arguments. I take the simulated Intelligence argument the same way. Suppose you could create a simulation of an intelligence that was indistinguishable from a real one? Well then, you'd have created an artificial intelligence. If such a thing reported that it experienced qualia I'd have no reason to doubt it. Edit: to put it differently. Suppose I built a model of a Formula 1 engine. I used different materials at a different scale and used a different fuel, but to precise tolerances so that it could actually run. Would it be a Formula 1 engine? No. Would it be an internal combustion engine? Of course, nobody would doubt it.
      - SomeStupidPoint 10y ago
        I think you're wrong about them being "special snowflake" arguments, and likely miss the point of them. Those arguments are very low-level in the intellectual stack, and can only address matters of subjective self because what they seek to establish or discuss is more fundamental than concepts like objectivity. (Well, cogito ergo sum is establishing an objective fact from a subjective one to give a basis for later objective discovery.) Any full accounting of the world must explain the mechanism by which I experience it, or it hasn't explained the only part of the world Im sure exists (my experience of it), and hence can't be a full accounting. You can have a very good predictive model for features of that experience, but neglecting that experience -- qualia -- is leaving a major thing unexplained. Similarly, cogito ergo sum is likely better phrased as "computation ergo existence" -- the process of doubting is a form of doing something, and so something must exist which is doing that (or is that process). This establishes that there must be some sort of existence, even if it's just a brain in a jar, random memory from quantum noise, etc. You can't doubt there's an existence, because the very act of doubting is proof of existing. You can only doubt the form of it. I also disagree that we'd have no reason to doubt the claim, but I agree we have no a prior reason to reject it. Your edit also makes a major assumption: that we know what causes qualia (our brain structure). That's the very thing being debated, so you're just begging the question.
        simonh 10y ago
  - codebolt 10y ago
    All I know is that I experience qualia. And I believe that you and all other humans do too, but perhaps some people just aren't aware of it in the same way as I am. As someone who has a pretty good grasp of both physics and computer science, I am personally convinced that there is no way a circuit board could give rise to the same type of subjective experience of qualia that I am experiencing. I know that's not really an argument, but just because I can't express my conviction in clearer terms doesn't make it any less real to me.
- michaelmrose 10y ago
  The universe is composed of particles, waves, or strings or whatever you prefer math describes each constituent part so why does math not describe the whole?
  - codebolt 10y ago
    Like I said, I don't accept this physicalist assertion, because it ignores the problem of qualia and the Penrose-Lucas argument (which demonstrates quite clearly how the human mind is able to violate Gödels incompleteness theorems, and therefore is not equivalent to any purely computational system).
    - Sunset 10y ago
      >the human mind is able to violate Gödels incompleteness theorems This is why philosophy majors should lay off the math and biology arguments.
      - codebolt 10y ago
        I was never a phil major. On the contrary, I have degrees in physics and computer science. My introduction to this idea came from reading the books of Roger Penrose, a man I have a great deal of intellectual respect for.
    - gjm11 10y ago
      No, the Penrose-Lucas argument does not demonstrate any such thing quite clearly. In fact, the argument was refuted in print before Lucas ever published it, in a nice paper called "Minds and machines" by Hilary Putnam. Exactly where it fails depends on exactly how it's stated, but here's a sketch: Goedel proved that a formal system powerful enough to talk about mathematics either is inconsistent or else cannot prove its own consistency. Lucas and his followers claim that human mathematicians have no such limits; presented with such a system they can just see that it's consistent. In Lucas's version we look at some particular candidate system that might implement a human being, and just see it's consistent. In Penrose's version we look at mathematics as a whole and just know it's consistent. But this is all nonsense. Real human mathematicians don't look at the sort of system that might implement a human being (still less, the totality of all mathematicians working together) and "just see" it's consistent. They don't even look at the nice streamlined formal systems they've made specifically for doing formalized mathematics in and "just see" that. Frege's system was inconsistent and he didn't notice after writing two volumes on it. (Russell famously pointed out an inconsistency.) Quine's ML was inconsistent and he didn't notice until Wang pointed it out. For all we know there might be some inconsistency lurking in ZF; it seems like a very good guess that there isn't, but that's all. And, I repeat, those are highly streamlined systems that don't attempt to do anything nearly so complicated as describing the complete behaviour of an actual mathematician's mind. We do sometimes attempt to study computer hardware and software -- systems a bit more like actual human minds, but still orders of magnitude simpler -- using formal methods. Sometimes we try to prove them correct. These proofs are also often wrong, which is why hardware and software have bugs. (In some cases we're pretty confident about relatively large systems; guess what?, the correctness proofs for those are done by computer and there's no "just seeing" about them.) The idea that a human being could look at a formal system representing the entirety of what their brain does and "just know" that it's consistent is not just wrong, it's one of the wrongest things any otherwise intelligent human being has ever suggested. But that is (part of) what it would take to show that the formal system didn't really model them perfectly. This is far from being the only major error in the Lucas-Penrose argument, but it's the worst one.
- ravitation 10y ago
  The fact that it ignores two things that are controversial at best seems to not really be a problem... Qualia's existence is more or less unprovable given its definition, and there are numerous objections to the Penrose-Lucas argument. Using either as a basis for an argument is essentially the same as basing an argument in faith.
  - visarga 10y ago
    In my opinion, qualia is just a word that stands in for agent-centric perception. For a reinforcement learning agent (such as human, animal, robot or AlphaGo) qualia is the combined effect of perception and value function. I think Chalmers tries to introduce a kind of dualism here - he's saying that human experience is something special, unlike other mechanical processes (which can only be mere p-zombies). I don't think it is a good idea to turn to dualism because it has been proven flawed and leads to philosophical conundrums. I think current day philosophy doesn't properly appreciate the insights coming from AI. We have seen AI give amazing results in perception : images, sounds, video - it's no mystery any more. You just put 100 layers deep convolutional nets to solve the problem from data. Philosophers still talk like we don't know how perception works, or that it results in ontologically special qualia. Another very important AI insight that is being ignored by contemporary philosophers is Reinforcement Learning. We have made great advances in intelligent behavior, and RL concepts (agent, environment, reward, and learning) are better suited for explaining human consciousness than traditional concepts such as free will, qualia and Chinese Rooms. Wittgenstein's concept of language games is apparent in reinforcement learning. There has been a recent paper about agents evolving a new language by trying to solve a problem together. Also, language philosophy should take a look at word embeddings. Maybe philosophy needs more grounding in AI.
TekMol 10y ago
Could you define "explanatory" in this context? When you say "God did it" - how did he do it? The simulation idea often involves concepts like computers and turing completeness. Not sure those meet your idea of "explanatory" here. But they explain how it could be done. While I never saw an explanation how God did it.
sebleon 10y ago
*disclaimer: no explanatory power, just food for thought 'cogito, ergo sum' We could very well be 'real' consciousnesses being fed artificial sensory data. While we would exist outside the simulation, our perception of objective reality might be fake.
- bambax 10y ago
  That's the Matrix, exactly. But they have flip phones there.
  - sebleon 10y ago
    Ha, the flip phones are key. They must have algorithmically calculated that the 90s were the optimum time to live a false life. I wonder why the machines made people live boring lives - seems like a great way to get them to wonder "is there more to life than this?"
RyanCavanaugh 10y ago
Let's say that for a given set of physical laws, you get some "computational power" P, which characterizes how hard it is do to computation using those laws. You could imagine a universe with lower P than ours, where light was much slower, or the only workable transistor had a switching time on the order of seconds. Given a universe with computational power P, you can simulate a "universe" of something like P * 10^-100. For example, a Minecraft world is a universe with different physical laws, in which you could perform even slower and worse simulations, and you can make "turtles all the way down" at lower and lower P. The claim that our universe is not simulated, then, is nearly equal to the claim that the physical laws we have is the absolute highest P that could ever exist. Since we know we can simulate universes of much lower P than ours, we ought to have very good reason to assert that there is no universe of much higher P than ours. Given a finite speed of light in our universe, yet nonlocal effects (Bell inequalities) which appear to take instantaneous effect, we could perhaps fathom a universe of higher P created by having a method of communication which occurred instantaneously. Add to this more dimensions in time and space, etc... literally nothing is off the table for a "smarter" universe to be conceived of, because the containing universe's physical laws need bear no resemblance to our own. Barring a literal divine intervention, though, it's all completely unfalsifiable, but I think it's more nuanced than "God did it".
- teraflop 10y ago
  I think the Minecraft analogy is illustrative. In Minecraft, you can use redstone circuits to construct logic gates, and use those gates to build computational devices that are Turing-complete, in theory. But it's not possible to scale such devices up arbitrarily; you can build a simple CPU, but nothing that even approaches being able to run a nested copy of Minecraft. There are hard upper bounds on the amount of data that the simulation can cope with at once. (You can imagine patching Minecraft to allow keeping more chunks loaded at once, but you can't scale it up by very many orders of magnitude before you end up with something that can't run efficiently on any hardware that physically exists.) Similarly, as Scott Aaronson describes in the article we're discussing, it's likely that there are finite bounds on how much computation can possibly be done before the heat death of our own universe. So it's fair to be skeptical that a tower of "turtles all the way down" could ever possibly exist, at least on a universal scale. If there's no tall hierarchy, then the anthropic argument (which says that we're unlikely to be at the top) breaks down. You can certainly hypothesize higher levels which have infinitely fast communication, or other kinds of special properties that make deep simulations more feasible. (Greg Egan proposed one such cosmology in his novel Permutation City.) But you don't get to assume that and still use simulations within our own universe as examples, because you're talking about something entirely different.

snowwrestler 10y ago

Here's what I wrote in a comment here last year about the Bostrom simulation argument specifically: The simulation argument, going back to Bostrom, relies on two flaws. 1) It leverages our optimism to corrupt our understanding of statistics and logic. It essentially says that if you think humanity doesn't destroy itself, then our descendants will probably try to simulate us. But of course if you just take a statistical view of the potential future ordered states of the universe, there are FAR more potential future states in which we don't exist, than states in which we do. The chances we are living in a simulation now are equally as small. 2) Bostrom hypothesizes that our descendants will try to simulate us. But it is impossible to completely simulate a system from inside that system--that's basic thermodynamics. So simulation proponents argue that our simulated reality is running in a more complex universe than we experience. But if that is the case, then the beings running the simulation are not our descendants! They're the descendants of whatever more complex beings came before them. Once again the central logic of the argument fails.

baddox 10y ago
> But it is impossible to completely simulate a system from inside that system--that's basic thermodynamics I haven't heard quite that argument before. Couldn't it just be simulated slower than real-time? Or is memory the issue?
- fsloth 10y ago
  "I haven't heard quite that argument before. Couldn't it just be simulated slower than real-time? Or is memory the issue?" The "real time" in simulation is not affected by how long a single time step takes to evaluate in the real world. https://xkcd.com/505/ https://xkcd.com/505/
- psyc 10y ago
  Regarding "Basic Thermo", everything we 'know', we subjectively acquired over a tiny period of time, through a game of telephone that refers to the current universe. We're really in no position to comment, in absolutes, on the nature of the parent universes.
- 10y ago

AnonNo15 10y ago

I had thought about this idea and came to the conclusion that if the full universe simulation is ever possible, it is highly likely that we are living in one right now. And the only way to prove it is possible, is to attempt to simulate one.

baddox 10y ago
Your first sentence is precisely Bostrom's argument, which is pretty much the canonical argument for the simulation hypothesis.
- visarga 10y ago
  And thus we open the door again for Intelligent Design. If we live in a simulation, then we could be the creation of an intelligent and powerful designer.
  - AnonNo15 10y ago
    The point about unfalsifiability is still valid. Even if we can simulate sentient life we still can't prove we ourselves are simulated or not.

deleted 10y ago

[deleted]

moomin 10y ago

Until someone demonstrates a jailbreak, I'm going to regard this hypothesis as moot.

deleted 10y ago
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ftlio 10y ago
Timothy Leary is a double entendre here...

planetjones 10y ago

But couldn't our universe be being simulated by a species far more advanced and discrete to anything the human race has ever encountered? How do we know that another form of life doesn't find everything that we find super complex extremely trivial ?

moxious 10y ago
It could be the case that we are being simulated by a far superior alien species. It could also be that invisible pink unicorns in the 15th dimension control all of our thoughts and only want us to believe this. Without being tongue in cheek, I'll observe that the empirical evidence for both of these ideas is equal in quantity. We don't know for sure that these things aren't true. But to ask that question is to inappropriately shift the burden of proof away from the claimer. Whoever claims something (we live in a simulation) should put up the evidence or get out. It's not up to bystanders to disprove the assertion. Connecting this to current events, even the president of the USA doesn't get to make baseless claims that his predecessor wiretapped him and get away with shifting the burden of proof to the FBI to prove he wasn't. This "reversal of burden of proof" is a classic but invalid way to make a point.
- sillysaurus3 10y ago
  There are many questions in life that are interesting to consider, independent of whether they're falsifiable. It tends to get boring to consider only questions that can be experimentally proven, though different people have different interests. Questions about society and human nature are worth considering, for example, but it's difficult to do controlled experiments. There's some truth to "watch out for wishful thinking," but usually conversations about the actual topic are more interesting.
  - Swizec 10y ago
    The part where "is this a simulation" becomes an uninteresting question is when you ask "Does it matter?". Would answering the question of whether we're in a simulation have any impact on your behavior, thoughts, and actions? Probably not. So what does it matter? My high school physics teacher once said that, if we ever find something that is outside the universe, then we will obviously be smart enough to call that the universe also. Because "universe" is a definition that means "everything". Similarly, if we ever find a reality beyond reality, we'll just call it reality. Because that's how it's defined. It means "everything". Or put another way: Of course we live in a simulation. Your experience of the world is just an emergent property of how your senses and neural system interact. There's no real reality. You're already trapped in a dark box doing fly-by-instruments using signals processing to interpret what your nervous system is detecting. Is that not already a simulation anyway? Maybe not. Maybe it depends on how you define "you". Fundamentally, would knowing that you're in a simulation change anything?

leni536 10y ago

The statement "we live in a simulation" is not falsifiable. For me this question is simply not interesting.

intjk 10y ago
At the end of the article, Scott essentially says the same thing, but emphasizing the other side of the coin: > [...] the question of whether the universe “really” “is” a simulation has barely come up. Why would it, when there are so many more fruitful things to ask?
- inopinatus 10y ago
  I always felt that the point of asking this question was not the answer itself, but that theorising how it might be implemented could lead to hacking the sandbox. IANATP but I've read, for example, that violating Lorentz invariance is an active research area.
  - XorNot 10y ago
    Or looking for aliasing from a lattice QCD simulation in cosmic microwave background...
fsloth 10y ago
That's my take on it too. The history of physics has shown, though, that it pays in interesting ways to go through every crazy idea until it's actually refuted or understood to be wrong.
- Cookingboy 10y ago
  But this is not physics, or science, unless you can have falsifiable claims. Otherwise it's just philosophy or metaphysics, which does not warrant a scientific discussion.
bambax 10y ago
Also, it doesn't explain anything, and esp. nothing about the simulators: are they themselves simulated (and so it's turtles all the way down, again) or are they not? And if not, why not, and who are they? etc.

pilingual 10y ago

It's amusing that the point of the blog post was how refreshing it was to be at the Stanford conference with bright minds talking about stimulating new topics; yet the comments here on HN continue to discuss the tired topic.

tempodox 10y ago
You couldn't simulate that if you tried.

z3t4 10y ago

I've been thinking about distributed databases lately and how such a system should be designed. How does nature do it ... ? (quantum mechanics)

polotics 10y ago

Contributing to the debate: How frequently do you fire up sim-city / how frequently do you fix up lunch?

Myrmornis 10y ago

Can someone explain the first bit of the last sentence? > if our world is a simulation, then whoever is simulating it seems to have a clear preference for the 2-norm over the 1-norm Is it basically saying that space looks Euclidean at a range of scales and Pythagoras crops up everywhere or is it saying something else / more sophisticated? What would the Universe look like if its creator favored a 1-norm?

gjm11 10y ago
I think he's referring less to the geometry of space(-time) and more to the structure of quantum mechanics. Classical probabilities are positive real numbers that add up to 1. (The 1-norm of the vector of probabilities is 1.) Quantum ampltiudes are complex numbers whose squared absolute values add up to 1. (The 2-norm of the vector of amplitudes is 1.) A universe made by someone who preferred 1-norms would more likely be classical rather than quantum. For more on this from the author of the linked blogpost, see here: http://www.scottaaronson.com/democritus/lec9.html http://www.scottaaronson.com/democritus/lec9.html or the corresponding bit in his excellent book "Quantum computing since Democritus".
- Myrmornis 10y ago
  Thanks! That was a really helpful reply. Started reading the Aaronson intro to QM you linked and it does seem like a very direct and understandable approach to the subject.

tazjin 10y ago

I experienced a series of extremely unlikely coincidences recently and one of my first thoughts was that if The Sims was a sufficiently advanced game I'd be doing those sorts of things to the characters.

lwhalen 10y ago
Do tell!
egeozcan 10y ago
I used to take writing lessons and the teacher always said that the coincidences only happen in real life, not in stories because that wouldn't be realistic.

js8 10y ago

I don't understand why is simulation even necessary. Simulation argument says that our universe and consciousness is pretty much just some sort of mathematical structure, that is being manipulated according to some simple laws as it evolves through what we call time. But then, isn't the only requirement for beings inside this structure to perceive it as such that the structure exists? Do you need to really physically manipulate it? To put it differently, what if the designers of the simulation could come up with some theorem that would let them correctly skip hundreds of years of simulating something. Would beings in those hundreds of years still existed, even though it wasn't actually executed? What if they just calculated the final answer? Would we then exist? So, to me, either this is nonsense, and we are not in simulation, or, any kind of mathematical structure that can possibly exist somehow "exists" and no "creator" is needed. But neither of those two options is a good argument for existence of simulation creator.

pka 10y ago
That's intersting. If the universe could be simulated, you could, in theory, run that simulation on a (very large) piece of paper by hand. Running the simulation would then be equivalent to calculating some numbers and writing them down. Basically, if I wrote down the correct sequence of numbers, I could simulate you. But is calculating those numbers actually necessary? Is it enough to just have the result of that computation without performing the actual steps to obtain it? If yes, then a random number generator would be all that is needed to simulate our (and infinitely many other) universes. And if that's the case, maybe it's not such a big leap to imagine that the mere existence of the physical laws as an abstract concept is enough to give rise to a simulation?
- carry_bit 10y ago
  > And if that's the case, maybe it's not such a big leap to imagine that the mere existence of the physical laws as an abstract concept is enough to give rise to a simulation? Calculating it just provides a window into the simulation; it still exists (in an abstract mathematical sense) even if you're not looking.
- xinyhn 10y ago

Insanity 10y ago

I am not sure what to make of the whole universe-is-a-simulation argument. The problem is that, this is as far as I know, not an hypothesis we could ever hope to prove. Not any more than we can proof that a diety exists outside of this world. I highly doubt that there is a higher creature, whether that would be a God of some kind, or a whole civilization outside of our universe that somehow simulates us. But let's for entertainment suppose that we are in fact a simulation. Would that not immediatly raise the question "why"? If we are a simulation I would really like to know the reason for being simulated. What do they hope to reach with simulating a life like ours? I fear we could never find a satisfactory answer to these questions. I also agree with the statement that this brings us back to a more mythological explanation of the universe and life around us. It'd make more sense to try and explain our universe without that hypothesis to me. Another argument that I'd like to raise against the universe-simulation hypothesis is the following. Humans like to see the world around them in terms of the technology that, at that moment, is considered modern and which they like. For example, Freud compared the human brain to the steam engine, which at that point was modern technology. Today, we compare the brain to a computer, and we even go as far as to consider the whole universe might be similated in one. Maybe just because that is what we consider 'modern' at the moment? In 1000 years from now, humans might think it's silly to think of the brain as a computer and rather think of it in terms of technology X, and the universe is technology Y.

glaberficken 10y ago
> But let's for entertainment suppose that we are in fact a simulation. Would that not immediatly raise the question "why"? If we are a simulation I would really like to know the reason for being simulated. What do they hope to reach with simulating a life like ours? They would hope to reach the exact same answers that we do when we simulate things inside our own computers. To understand our own reality better. Imagine for a second you are that "external" (to us) God or civilization. You simulate this whole other universe (ours) to find out if it's possible that your own reality is a simulation.
simonh 10y ago
I think it's interesting to speculate what the simulation argument means for religion. The existence of a simulation creator doesn't actually disprove the existence of an ultimate god, after all the beings running the simulation might have a divine creator, so it just pushes the question up a level. But it does pose a problem for imminent religions that believe that god intervenes in the world to cause miracles. How do you know that any given miracle was caused by the ultimate god and not the simulation sysadmins editing the simulation? The whole question of miracles and divine providence becomes deeply problematic.

TelmoMenezes 10y ago

Something that most people never consider in these discussions: If you accept the hypothesis that mind is generated by a computation, and that this computation is finite, then the same computation that produces "you" can be performed in different places and at different times. The same computation can be performed inside a simulation, inside a simulation inside a simulation and so on. Whatever environment around you can be included in this computation. As long as the computation is finite the larger and/or more temporally extended the universe is, the higher the probability that the computation that is generating this current moment for you is being executed more than once. If the universe is infinite in some sense, this probability converges to 1. And yet you would have no way of knowing that this is happening. So I claim that, if you assume that mind is generated by a computation, then then question of wether we are in a simulation or not can be replied with "both" or "it doesn't matter".

GuiA 10y ago
Except that your mind is not an isolatable computation - it is influenced by your body, which is in turn influenced by its immediate environment, in turn influenced by the rest of the universe in an ever expanding nested fashion. So if you want to simulate yourself, you have to simulate the universe.
- deleted 10y ago
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- Ntrails 10y ago
  > So if you want to simulate yourself, you have to simulate the universe. This doesn't gel with me. I go back to brain in a jar stuff - I'm just streaming packets of data from nerves and processing them. Whether the "body" I'm responding to is real is pretty hard to guarentee.
  - GuiA 10y ago
    There's evidence that your brain is influenced by e.g. certain chemicals in your bloodstream produced by gut bacteria. https://www.theatlantic.com/health/archive/2015/06/gut-bacteria-on-the-brain/395918/ https://www.theatlantic.com/health/archive/2015/06/gut-bacte... So the brain in a jar model where the only interface with the real world is through nerves is most probably wrong; now your jar also needs a stomach with a fully developed microbial ecosystem. And that's just one recent mechanism that was investigated; there are probably many others.

Aeolun 10y ago

I recently read a short story about this exact subject: https://qntm.org/responsibility https://qntm.org/responsibility I think it quite accurately represents the mind-fuck that this causes.

jfries 10y ago
Wow that's quite a thought experiment. Fun twist at the end, I wonder how society would react to this realization.

julianpye 10y ago

Regarding AI and God and religion - here is a blog post that I wrote that suggests that being in a simulation actually increases our chances for a religious afterlife. https://medium.com/@photodiary/implementing-religion-in-ai-life-simulations-45e6e293b8aa#.giqw4s25n https://medium.com/@photodiary/implementing-religion-in-ai-l...

sillysaurus3 10y ago
This runs into the question of whether you're a single person. https://www.youtube.com/watch?v=nQHBAdShgYI https://www.youtube.com/watch?v=nQHBAdShgYI https://www.youtube.com/watch?v=qjfaoe847qQ https://www.youtube.com/watch?v=qjfaoe847qQ If you transplant half your brain into another body, and both of you wake up, which one is you? If you start swapping your atoms one by one with someone else, and neither of you die, at what point do you become the other person? Unfortunately questions like that are necessary in order to address the idea of a simulation afterlife. If our bodies are literally who we are, and our bodies disperse, it may not make sense to say that we can still be simulated after our bodies disappear.
jonathanstrange 10y ago
That's a non-sequitur you have there, because you do not even attempt to explain why there should be a case distinction. To be fair, even Nick Bostrom's original simulation argument is also based on several fairly unfounded and not very plausible assumptions (e.g. what extremely advanced societies would do). Much of the debate seems to be based on speculation.
- julianpye 10y ago
  Well, my blog-post is half-serious. The bigger question from it would be why the hell the Universe would be implemented in Java :)
  - evanb 10y ago
    Honestly, we hacked most of it together with perl. https://www.xkcd.com/224/ https://www.xkcd.com/224/

KCFforecast 10y ago

How to solve any problem quickly: Program your computer to solve a problem in a million years time, then go for a travel at the speed of light, come back to your home and consult the solution of your problem, you have been traveling only a few days but your computer has been doing computation a million of years, so you now have the solution, a quick one. Just alter that system to use the relative time to have computer working millions of years to solve problems for you and you can have the solution in days. Call it photon computation to give the system a name.

StavrosK 10y ago
That's not "quickly". That's your consciousness slowing down to a rate of one day per million years.
- KCFforecast 10y ago
  You don't solve the problem by yourself, that problem is solved for you on system A, in system A a million years have lapsed but in your life only a few days have passed.
  - StavrosK 10y ago
    I know, but that's not "quickly". It's just that time passes slowly for you. "Quickly" would be if my friends and family were still alive and the world were recognizable (and there) by the time I got back.
    - KCFforecast 10y ago
      Try this version instead: There is a rocket to be launched for people to upload problems to solve, the rocket travels in such a way that it is able to solve all the problems and come back to tell people the solution. The way it solves the problem is by orbiting around a tiny planet full of computers devoted to compute the problems they are communicated of. The problem seems to be how to locate the observers. Edited: time dilation and computation: https://arxiv.org/pdf/0907.1579.pdf https://arxiv.org/pdf/0907.1579.pdf

tempodox 10y ago

Eventually, it comes down to the question whether any self-respecting non-simulated universe would actually tolerate that amount of the-universe-is-a-simulation braincrackery. My simulation of Occam is turning in his grave.

mrleiter 10y ago

Immanuel Kant foresaw all this. In his seminal work "Critique of pure reason" he argues that our pure reason, as opposed to the pure mind, always tries to look for the absolute, the absolute of all conditionals. This leads our reason to look beyond empirically observable objects. Those objects that have their origin only in pure reason is what he calls "ideas". Those ideas can be separated into three categories, namely psychologia rationalis (Soul), cosmologia rationalis (World) and theologie transcendentaus (God, or Being of all Beings). Ideas can never be proven or falsified for that matter. But they have their use: be a guideline for our living. This is where Kant's famous practical philosophy stems from.

Aqueous 10y ago
What Kant said about the world of appearances (phenomena) and the world of objects in themselves (noumena) is also interesting especially for this discussion. He said we can know that there is a noumenal reality - a reality completely independent of our perception - but we just can't say anything meaningful about its character at all, since we can only perceive the world of appearances, or reality as it is subject to the conditions of our perception. For Kant it might not be meaningful at all to say that our 'world of appearances' is actually a simulation, for that would be implying something about the character of reality-in-itself that we simply cannot apprehend. As an aside, his proof that a world of objects-in-themselves exists at all is incredibly interesting and provides what in my view has been one of the only compelling answers to the radical skepticism of Hume (the idea that we cannot prove the existence of an external world).
- CuriouslyC 10y ago
  The problem with Kant's view of an objective outside world is that it is to some degree demonstrably false. Quantum physics shows us that the observed and the observer constitute a system, and the nature of the observer influences the properties of that system as a whole. That influence might be small enough on very large scales to call the observed to some degree "objective" but we don't know that for sure.
  - deleted 10y ago

yk 10y ago

Putnam has a very nice argument in his Brains in a vat paper. [1] Basically he argues that a brain in a box lacks any causal connection to the box, the brain does never learn any information about the box. The idea "I am a brain in a box" lacks a reference and any reasoning about it is at best a lucky guess, even if true. The issue is the similar, but more fundamental, as me claiming "you have a misplaced comma in the second sentence of your next email." That may or may not be true, but if it is true it is certainly not based on sound reasoning. [1] http://ieas.unideb.hu/admin/file_2908.pdf http://ieas.unideb.hu/admin/file_2908.pdf

wallace_f 10y ago

The author writes about exceptional attendees at the conference: >...from Lenny Susskind and Don Page and [and..., and..., and...] This is what I don't like about academia. It's equivalent to "shout outs" you see 12-year-olds do in Call of Duty tournament games. I know everyone knows academia is filled with politics, but if scientists are going to circle jerk, please jerk on ideas, not each other.

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Geee 10y ago

My hypothesis is that we are in a natural simulation, i.e. simulated by a computer which evolved by itself. Or layers of simulations. The "base universe" should be the simplest possible universe that is very simple, but capable of evolving the first simulation, which is more complex universe.

wnkrshm 10y ago

I don't understand how rejecting that the state of the universe is fundamentally computable is the same as rejecting the Church-Turing Thesis. Rejecting the computability of the universe's state is more fundamental: It rejects one of the assumptions of the Church-Turing Thesis, namely that there is a function to compute at all.

amelius 10y ago

My personal favorite (untested) theory is that the universe does not exist at all in reality, but only in an abstract way through a rewrite system that combines "nothingness with nothingness" ad infinitum [1, 2] [1] http://www.worldscientific.com/worldscibooks/10.1142/6544 http://www.worldscientific.com/worldscibooks/10.1142/6544 [2] http://www.youtube.com/watch?v=W2XdhzCORbo http://www.youtube.com/watch?v=W2XdhzCORbo

umanwizard 10y ago

Casually using phrases like "the absolute of all conditionals" as though anyone is supposed to understand what that means makes your whole post sound like gibberish. This is why philosophy is the butt of jokes.

bgilroy26 10y ago
We have the Internet. If the parent commenter thought a more digestible summary or paraphrase of "the absolute of all conditionals" would have been helpful, they would have written it that way. If you're frustrated that it's opaque, and you care about understand the chance to do so is as near as googling "Kant absolute of all conditionals". If you don't care about understanding, why complain?
- consz 10y ago
  I spent about a minute looking at the results for "Kant absolute of all conditionals" on google, that phrase doesn't have any close hits, I think its fair to describe this phrase as non-trivial to understand just through googling, so I think your snark is unwarranted.
  - sesqu 10y ago
    I spent a minute looking at the results of that phrase on ddg, and got a hit on the book in question. While it's not a direct quote, a search of the book finds this line: > On the one hand: We set limits to reason, preventing it from leaving the guiding-thread of empirical conditions and straying into the transcendent and explaining things in terms that can’t be cashed out empirically. And also, on the other hand (this being my present point): We set limits to the law of the purely empirical use of the understanding, preventing it from making decisions about the possibility of things in general—i.e. of things of any sort—and ruling that intelligible things are not merely incapable of explaining appearances but are impossible. I assume that's what OP meant.
- umanwizard 10y ago
  Are you trolling or something? I did google it and there were no relevant results. Putting "absolute of all conditionals" into Google gives a bunch of stuff about absolute convergence in calculus without quotes, and no results at all with quotes.

jmcdiesel 10y ago

I think its a great question to ponder on, and I think anyone making a claim in either direction is wrong... To claim it is a simulation is just overreaching, because there is no real evidence. To claim its not, that its not possible, is hubris - just because we can't simulate it now doesn't mean in a million years a society following ours wouldn't be able to, and if you say even a society in a billion years would be able to, then you're saying its possible, and if its possible, than you can't say we're not. I love unanswerable questions. Especially with a little sativa in my bowl. :)

draw_down 10y ago

I'm reminded of when I was in school, and took western philosophy to try to get some help with how to think about life and the world. Instead what I got was a bunch of, like, Descartes staring at a candle and trying to figure out if it's real. My thought then and now has been, it doesn't matter. This existence has certain rules to it. Drink poison and you die, hurt people and go to jail. It's up to us to figure out how to navigate that for a time, and that's all we get. As far as we know. Even if you knew what was outside what we call reality, even if you knew the form of the simulation- what could be done with that information? I wonder if this sort of thinking is ultimately propelled by a fear of death or some other impetus compelling people to deny that reality is what it really is. Maybe it's somehow comforting to think that your loved ones don't really die and neither do you, suffering isn't real, it's just qubits being shuffled around in a formal game that lacks higher meaning.

6stringmerc 10y ago

I'm nurturing a thought that the experience of Human Life is much more akin to a biological radio antennae picking up on a cosmic "living" code base being broadcast somewhere out there which encompasses the entire known universe. That's where the postulation stops and I just go with "turtles all the way down" after that.

akssri 10y ago

I'm a string in X^*, and the universe is a real number.

ouid 10y ago

This question is so fundamentally bullshit that a new, stronger form of the word fundamental is required to truly describe it. Of course the universe is a simulation. There are either more fundamental processes occurring which explain the behavior of our observations, or it is the identity simulation. Newtonian laws are simulated with quantum laws, atoms are simulated with quarks, time is simulated by statistical relationships, and chemical interactions within the rules of the other abstractions are sufficient to simulate our observations. If you believe that this question is about whether or not there is some anthropomorphic supervisor of the simulation, then THAT is the hypothesis you should be putting forward, not that the universe is a simulation, which is meaningless.

mannykannot 10y ago

Maybe I am just not following, but the arguments of Sabine Hossenfelder, Scott Aaronson, and of a great many posts here seem to assume that reality is something like what we (or should I say I?) experience. If our (my) universe is a simulation, nothing we (I) perceive about it is trustworthy, and that applies as much to odds as to absolutes. Has there been any argument against the possibility that does not either beg the question by tacitly assuming that our perceptions inform us about the ultimate reality, or alternatively squeeze the essence of the problem into a tight little knot and thereafter avoid dealing with it directly, as I think Kant (among others) did? I do not actually think I am a simulation, but I cannot argue against it.