5 ms·

Not if compression is involved.

qingcharles 2y ago
This is why I have a totally unhinged belief that it might be possible to emulate the universe inside the universe itself.
- joseph_b 2y ago
  Everything sounds so simple until we try to explain it. If the emulation is contained inside the universe being emulated, do you think the emulated universe includes the emulation contained within it? Does the emulation now contain another emulation? If so, now many emulations?
  - TuringTourist 2y ago
    And if that is the case, the odds are basically 0 that we happen to be the first of an infinite number of universes emulating themselves
    - airstrike 2y ago
      But that really has no bearing on our emulated selves. For us, this is the one reality that matters
  - ridgeguy 2y ago
    Pretty sure it's emulations all the way down.
- phkahler 2y ago
  I don't think that's unhinged. One might think the emulation must contain a subset of the state variables of the universe. But if there are no state variables that problem goes away. I have reason to believe there are no state variables.
- bongodongobob 2y ago
  I don't think there's any reason you couldn't but the simulation might move so slowly that it's not useful.
  - qingcharles 2y ago
    There are two problems -- storing the state of your emulated universe (storage space) and the operating speed. You can undoubtably run it at less than realtime, and might even be able to find a way to scrub fwd/rev through time to the interesting bits. The bigger issue is how to store the data. If the universe is compressible we might be able to store it and operate on it. If it's not sanely compressible then we either need to use a large chunk, or all of, the universe's matter/energy to store the state of our emulator and any inhabitants of our universe would need to file written complaints in advance at Alpha Centauri if they did not consent to being subsumed into the Giant Grey Blob(tm).
- nonameiguess 2y ago
  It's frankly not all that clear what this even means. When cosmologists talk about the "universe," the generally mean the observable universe, which is all events that have ever happened in the past light-cone of the observer. Since space is expanding, that is constantly changing, with the expectation being that at some point, from the perspective of anything in our current galactic supercluster, everything else will become causally disconnected when the expansion rate exceeds the speed of light and will no longer be in "our" observable universe, where even then it isn't clear what "our" means as it's also likely by then that black holes will be the only baryonic matter still in existence, and there will no longer be humans, life, planets, or even light most of the time. As those black holes degrade via Hawking radiation over however many quadrillions of quadrillions of year, without gravitationally bound superstructures of any kind, eventually all fundamental particles will be causally disconnected from all others, permanently. What then does it mean to "emulate the universe inside the universe itself?" How do you emulate a single fundamental particle with only a single fundamental particle? What is the distinction between the emulation and the real thing? The real thing has nothing else to interact with, so it can't compute. It's state can't be measured because there is nothing to measure with. In short, I hesitate to speculate about what can and can't be done with the universe because what the universe even is will change quite drastically over long enough spans of time.
  - qingcharles 2y ago
    Well, I feel like an emulator for our universe should be able to boot off simply the initial seed value and a copy of the Total Laws of Physics(tm). If you could emulate it then you could access and see into all the parts of our universe which are currently unobservable. Of course, if you could emulate it sufficiently you should be able to scrub the timeline into the future and visit Milliways too.
  - joquarky 2y ago
    There's no point simulating a universe that lacks agents. When the last agent dies, the simulation should halt.
rbanffy 2y ago
Why would you think it’s not already? What we see is the observable state, not it’s underlying representation.
mr_toad 2y ago
As far as I understand it, the pigeonhole principle would mean that you can’t losslessly compress the entire universe.

This is why I have a totally unhinged belief that it might be possible to emulate the universe inside the universe itself.

joseph_b 2y ago
Everything sounds so simple until we try to explain it. If the emulation is contained inside the universe being emulated, do you think the emulated universe includes the emulation contained within it? Does the emulation now contain another emulation? If so, now many emulations?
- TuringTourist 2y ago
  And if that is the case, the odds are basically 0 that we happen to be the first of an infinite number of universes emulating themselves
  - airstrike 2y ago
    But that really has no bearing on our emulated selves. For us, this is the one reality that matters
- ridgeguy 2y ago
  Pretty sure it's emulations all the way down.
phkahler 2y ago
I don't think that's unhinged. One might think the emulation must contain a subset of the state variables of the universe. But if there are no state variables that problem goes away. I have reason to believe there are no state variables.
bongodongobob 2y ago
I don't think there's any reason you couldn't but the simulation might move so slowly that it's not useful.
- qingcharles 2y ago
  There are two problems -- storing the state of your emulated universe (storage space) and the operating speed. You can undoubtably run it at less than realtime, and might even be able to find a way to scrub fwd/rev through time to the interesting bits. The bigger issue is how to store the data. If the universe is compressible we might be able to store it and operate on it. If it's not sanely compressible then we either need to use a large chunk, or all of, the universe's matter/energy to store the state of our emulator and any inhabitants of our universe would need to file written complaints in advance at Alpha Centauri if they did not consent to being subsumed into the Giant Grey Blob(tm).
nonameiguess 2y ago
It's frankly not all that clear what this even means. When cosmologists talk about the "universe," the generally mean the observable universe, which is all events that have ever happened in the past light-cone of the observer. Since space is expanding, that is constantly changing, with the expectation being that at some point, from the perspective of anything in our current galactic supercluster, everything else will become causally disconnected when the expansion rate exceeds the speed of light and will no longer be in "our" observable universe, where even then it isn't clear what "our" means as it's also likely by then that black holes will be the only baryonic matter still in existence, and there will no longer be humans, life, planets, or even light most of the time. As those black holes degrade via Hawking radiation over however many quadrillions of quadrillions of year, without gravitationally bound superstructures of any kind, eventually all fundamental particles will be causally disconnected from all others, permanently. What then does it mean to "emulate the universe inside the universe itself?" How do you emulate a single fundamental particle with only a single fundamental particle? What is the distinction between the emulation and the real thing? The real thing has nothing else to interact with, so it can't compute. It's state can't be measured because there is nothing to measure with. In short, I hesitate to speculate about what can and can't be done with the universe because what the universe even is will change quite drastically over long enough spans of time.
- qingcharles 2y ago
  Well, I feel like an emulator for our universe should be able to boot off simply the initial seed value and a copy of the Total Laws of Physics(tm). If you could emulate it then you could access and see into all the parts of our universe which are currently unobservable. Of course, if you could emulate it sufficiently you should be able to scrub the timeline into the future and visit Milliways too.
- joquarky 2y ago
  There's no point simulating a universe that lacks agents. When the last agent dies, the simulation should halt.

rbanffy 2y ago

Why would you think it’s not already? What we see is the observable state, not it’s underlying representation.

mr_toad 2y ago

As far as I understand it, the pigeonhole principle would mean that you can’t losslessly compress the entire universe.