Silence Suggests Sim?

In 2010 I explained why I guess I’m not in a sim. In 2011 I explained why sims should be small, and focus on “interesting” folks. In 2001 I explained why it matters if you live in a sim.

Here is Tyler today:

If we are living in a simulation, does that resolve the Fermi paradox? I would think so. The “aliens” would be here, we just would not “see” them as such. … Should we expect to find alien civilizations in a simulation? The priors are not so clear. … For the time being, we are still in a “no aliens” do loop. … The Fermi paradox raises the likelihood that we are living in a simulation.

I don’t buy it. Let’s try two extreme cases. First, assume that the creatures who make your sim copy their own universe in the sim – if it has aliens, then you get aliens; if not, not. Here not seeing aliens says nothing about if you are in a sim.

Now assume the opposite, that whether the creatures running your sim give you aliens has no relation to whether or not they have aliens in their world. They decide whether to give you aliens based on the “story” (= useful sim) value of aliens, regardless of how realistic that seems to them. In this case if the scenario of your world seems to have especially high story value (relative to a real scenario), you should increase your suspicion that you are in a sim. And if your scenario seems to have an especially low story value, you should reduce your suspicion that you are in a sim.

It seems to me that if anything aliens would add to a story value. So not seeing aliens should lower your suspicion you are in a sim. And if you can’t tell if aliens help or hinder a sim story, then not seeing aliens gives no info about if you are in a sim.

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  • EB Hansen

    Maybe our sim is like “Against a Dark Background” by Banks

  • Matthew Baker

    When you say high story value I feel a bit confused. I tend to discredit that view of a future simulation as a complex story and view it more as a testing apparatus for a competing set of theories tested in an ancestral environment.

  • Matt

    It seems a bit bold to assume the likelihood of a simulation depends on how entertaining it is for the creator, and then evaluate the entertainment value of various universes from the point of view of an alian. It’s one possible framework to pick out of a hat, but I don’t see why its a controlling one.

    You’ve probably read Solaris by Lem. One of the themes of that book (and many religions) is how difficult it would be for humans to understand the workings of a truly higher level of intelligence. I think here you are applying very human motivations and evaluative techniques to the simulator. For example, you think aliens are more interesting than non-aliens. Fine. Why would you assume an intelligence capable of creating a universe would share your taste in what constitutes “interestingness”?

    • Adrian Ratnapala

      Well I have no idea about alien motivations and aesthetics. However, if they are motivated by trying to create a story that humans might like, then I feel the world not feel like God – if he exists – is hiding and covering every possible track.

  • Ben

    It seems to me that if anything aliens would add to a story value.

    It seems to me that having space for aliens but not knowing whether they’re out there may add even more story value–it’s the ultimate suspense story.

    Assuming our universe is a simulation, its creator could have made it without outer space. The existence of outer space thus increases my suspicion that I’m living in a simulation

  • Nancy Lebovitz

    Any thoughts about us being in a sim based in our universe (in other words, running on something built from the sort of matter we’re used to) vs. being in a sim running on something that has different physics?

  • zmil

    The probability of not having aliens in a sim does not have to be higher than the probability of having aliens in a sim. It just has to be higher than the probability of not having aliens in the real world. It is relatively easy to imagine that at least some Gamemasters decide to have at least some sims with no aliens. It is perhaps harder to explain the absence of aliens in the real world- i.e. Fermi paradox.

  • Sigivald

    And if you can’t tell if aliens help or hinder a sim story, then not seeing aliens gives no info about if you are in a sim.

    Since we can’t even guess as to what the simulator’s motive is, we can’t tell if we’re in a sim or not.

    (I maintain, as I think I have here previously, that the entire question is moot; it’s impossible to tell if “we’re simulated”, and it wouldn’t matter anyway.)

    • IVV


      Why ignosticism isn’t more popular I don’t understand.

    • Sister Y

      One thing we can say about our simulators, if they exist, is that they lack certain moral commitments: they do not care about our suffering, and they do not allow suffering participants to opt out. They certainly do not follow RH’s model of who should exist. The Problem of Evil applies to our simulators as much as to God.

      • nazgulnarsil

        not necessarily, the examples you see of extreme suffering might have no internal experience simulated.

      • Sister Y

        Yes – Bostrom-style, we can say that one of the following is true: (a) the simulators are evil, or (b) all suffering people are NPCs. Since I know I’m not an NPC, I know the simulators are evil, but cheery folks are in a more difficult epistemic position.

      • Finch

        I think there’s a third option: the simulators might not know about your existence. The simulation could exist for some other purpose, with humanity as an obscure and unexpected side effect.

      • Sister Y

        Ah yes, good point – the third prong of the Problem of Evil, omniscience.

      • Finch

        Fourth option: the simulators know that the suffering is somehow worthwhile or outweighed by other benefits it makes possible. Religious people often make similar arguments about gods.

        Fifth option: we are just over-weighting suffering in our analysis. Maybe it’s not really that bad and we shouldn’t take it so seriously. It’s just a dashboard indicator of your prospects for longevity and reproduction.

        I find the simulation argument implausible because either (1) it’s about the whole universe (which the Copernican in me thinks is most plausible), in which case that’s a lot of resources to expend, or (2) it’s somehow focused on me (the minimal alternative), and frankly while I’m an overconfident guy, I just don’t think I’m worthy of that kind of attention.

  • Mark M

    As species-centric as we are, we see Earth and humans as the star actors in our little Sim drama, but we may just be an unexpected and mostly unnoticed byproduct of a Sim ecosystem. The aliens may be out doing alien things with other aliens, and we’re noise in the background.

    Or we could be a Sim experiment to see if the world would have been better without prematurely aliens providing advanced technology to a world that wasn’t ready for it. Or to see if we would have eventually developed that technology on our own, or destroyed the world, without alien intervention.

    Or we’re an experiment to find what kind of life develops in a more (or less) oxygen rich environment. Aliens play no part in this experiment so there is no reason to include them.

    The point is that there are lots of reasons a Sim creator would include or exclude aliens in a Sim. Presence or absence of aliens is not evidence either way.

  • Larks

    Aliens might violate experimental conditions. I wouldn’t want my petri dishes being turned into paperclips.

  • arch1

    Robin, your analysis seems to sidestep Cowen’s point, which focuses on the need to better explain the no-aliens observation. Assume for the sake of argument that this observation has no decent explanation if we’re not in a sim. Since sim-without-aliens can provide such an explanation, our no-aliens observation should increase its plausibility.

    So I don’t buy the upshot of your analysis (which upshot is “no-observed-aliens -> sim-no-more-likely”) since your analysis leaves the no-aliens observation puzzlingly underexplained.

    Rather, I conclude (as I think Cowen does) “no-observed-aliens -> sim-without-aliens-more-likely.” (And as to why aliens don’t appear in the script, I frame no hypotheses:-).

  • jb

    I think a single civilization in an entire galaxy is an incredibly interesting story, myself.

    An even more interesting story is ‘create 100 nearly identical planets distributed evenly across the galaxy. Set them up so they achieve sexual reproduction at the exact same time. See what happens.”

    And then there’s the terrifying:

    “Set up a planet with an intelligent species, and let it run in isolation until it achieves technology X. Then unleash an alien invasion or some other catastrophe, and see what happens.”

  • richard silliker

    “The “aliens” would be here, we just would not “see” them as such.”

    I suspect it would matter if the aliens were organic or inorganic. It is all about the behaviour of mass.

    If and when an “artificial intelligence” is implemented I suspect it to be inorganic and unable to detect us.

  • Brian Nachbar

    To put zmil’s and arch1′s criticism on a more rigorous footing:
    “And if you can’t tell if aliens help or hinder a sim story, then not seeing aliens gives no info about if you are in a sim.”
    This claims that p(sim|silence) = p(sim) if p(silence|sim) is unknown. But actually, since p(sim|silence) = p(silence|sim)*p(sim)/p(silence), the claim is that “if you can’t tell if aliens help or hinder a sim story,” then p(silence|sim) = p(silence). But this doesn’t follow; if you have no information about p(silence|sim), you might set it equal to 1/2; if p(silence|not sim) is lower than that, silence is evidence for being in a sim.

    I agree that aliens probably add to a story, so I would set p(silence|sim) below 1/2, but I’m nowhere near certain enough to put it at the astronomically low values that constitute the low range of estimates for p(silence|not sim), and I’d be shocked if anyone claimed to be.

    • zmil

      Exactly. Thanks.

    • arch1

      Brian, really well put – thanks.

      I would just add that IMO Robin’s simplifying assumption that ‘story value’ is the only consideration affecting inclusion of aliens in a sim is a bit rash. It seems to me that there are a number of other considerations which might affect that decision (some of which are mentioned in other comments). Given this, basing one’s estimate of p(silence|sim) on story value alone may introduce a bias. I find it difficult to say more because we’re getting pretty far out on a speculative twig, if not leaf:-)

  • Pandaemoni

    Maybe they are running the simulation to determine what would have happened to Earth if humans had never met aliens.

  • multifoliaterose

    I’m surprised that nobody’s mentioned that it could be much less computationally intensive to run a sim of human experiences on earth than to run a sim of the entire apparent observable universe.

    The information content that gets through to earth is presumably many orders of magnitude lower than the information content of the information content that describes the observed universe if we’re not in a sim.

    Indeed, Robin has touched on the theme of the implications of bounded computational resources on sims in one of the blog posts that he links to:

    Today, small-scale coarse simulations are far cheaper than large-scale detailed simulations, and so we run far more of the first type than the second. I expect the same to hold for posthuman simulations of humans – most simulation resources will be allocated to simulations far smaller than an entire human history, and so most simulated humans would be found in such smaller simulations.

  • Robert Koslover

    1. By Occam’s razor, we are not in a sim.
    2. If we were in a sim, there would exist (or have existed) at least one set of “aliens” – the beings that created and/or are running the sim. And in that case, those beings would seem to be the only “aliens” that should actually matter much to us.

  • Zubon

    May I presume that we have some Civilization players in the reading audience? I’m usually a more peaceful than warlike player. There are three settings for barbarians: normal, off, or “raging.” Raging barbarian hordes can certainly make things more interesting, but they also tend to muck up my neat plans for civilization development. Sometimes you want to control or eliminate those potentially interesting variables.

    I’m also with Brian Nachbar and multifoliaterose.

  • TGGP

    Robin, what do you think of Jeff Kauffman’s take on brain emulation? It was linked in the comment’s at MR.

    • Robin Hanson

      This is his entire analysis:

      I think we’ll probably have a nematode simulation in about ten years. People have been working on this for at least 15 years [1], so that would be 25 years for a nematode simulation. The amount of discovery and innovation needed to simulate a nematode seems maybe 1/100th as much as for a person. [4] Naively this would say 100 * (15+10) or 2500 years for human whole brain emulation. More people would probably work on this if we had initial successes and it looked practical, though, giving us maybe a 10x boost? Which still is (100/10) * (15+10) or 250 years.

      He pulled these factors of 100 and 10 out of the air as far as I can see.

  • Peter Gerdes

    Presumably by not having aliens one could run a simulation of life on one world with considerably less computational costs by simply using vague approximations to handle all the physics outside of a narrow region around the planet of interest.

    • xxd

      @Peter Gerdes:


      So the question becomes this:
      If the mediocrity principle is true then would the universe create more computationally limited sims or more computationally unlimited sims?

      I think the evidence is in favor of more computationally limited sims but we don’t have sims running on quantum computers yet so the answer is not in…