5 ms·

Mathematical proof debunks idea the universe is a computer simulation

30 points by dxs 1y ago

deleted 1y ago
[deleted]
mihaic 1y ago
Would be fascinating if true, but I'd be very curious what kind of model of "reality" they actually have. The paper itself [1] seems quite compact and extremely high level, so I'm sure some heavy hitters would try to reformulate it. Would be the most unintuitive thing to happen since Bell's theorem [2]. [1] https://jhap.du.ac.ir/article_488.html https://jhap.du.ac.ir/article_488.html [2] https://en.wikipedia.org/wiki/Bell%27s_theorem https://en.wikipedia.org/wiki/Bell%27s_theorem
karmakaze 1y ago
> "Therefore, no physically complete and consistent theory of everything can be derived from computation alone. [...]" It wasn't stated why all truths need to be provable though. Perhaps the paper goes into this detail that I'd like explained.
- galaxyLogic 1y ago
  I think you nailed it. There are true statements which cannot be proven, yes. But those could be true statements also in the simulated universe. The simulation does not need to calculate the correct ANSWER to every question.
  - karmakaze 1y ago
    The incompleteness theorem doesn't even say that correct answers can't be computed, only that they can't be proven to be correct using the axioms of a consistent system.
    - galaxyLogic 1y ago
      Good point. But you can say there is always the question "Can this be proven with our rules of logic?" It's a curious thing, I wonder how to precisely define "proving without logic". Proof by "meta-thinking"?
- theturtlemoves 11mo ago
  Feels like the Halting Problem all over again...
ozb 1y ago
Almost every statement in this paper is wrong. The central claim in particular is not proven because a physical theory P need not be able to express statements like "there exists a number G, which, when interpreted as the text of a theory T, essentially states that the theory T itself is unprovable in the broader physical theory P" as an empirical physical fact.
- NoahZuniga 1y ago
  It's also very hard to verify the sources for some claims: I would expect the snag to be that many model theory results we have (Such as Gödel theorems) require quantifying over an infinite set, but that seems plausibly not possible to model in the physical universe. I quickly found this quote from the paper: > Arithmetic expressiveness; LQG can internally model the natural numbers with their basic operations. This is important as quantum gravity should reproduce calculations used for amplitudes, curvature scalars, entropy, etc in appropriate limits. Both string theory [34, 37] and LQG [35, 38] satisfy this by reproducing GR and QM in appropriate limits Here the citations are four entire books. How am I supposed to very that LQG can model N with that?
  - roywiggins 11mo ago
    Here's a dumber argument: suppose you simulate a Newtonian universe in a computer. We do this at a coarse scale all the time. Now, suppose we dedicate a few percentage of solar output to this project and out pops functioning artificial life that can think more or less like we do. Such an "organism" would be able to discover Gödel incompleteness just as well, and thus eventually conclude via the same chain of logic as this paper that the simulation hypothesis is false. While inside a simulation. Sure, I'm assuming here that nothing Gödel's brain did is fundamentally non-computable, but that's a pretty easy lift I think. Math is hard but it's not that hard.
    - ozb 11mo ago
      For what it's worth, while I find this "obvious" as well, given the Church-Turing Thesis etc, Nobel Prize-winning physicist and philosopher Roger Penrose famously does think that human brains require access to non-computable insights to do math.
ralph84 1y ago
Even if they prove our universe can’t be simulated in a computer built the way we build them, how can they prove there aren’t other ways to build computers?
- abemiller 1y ago
  Yea I mean a more generic version of the simulation theory is just that there is an "outside world" within which our universe exists in containment. Seems probably impossible to disprove (or prove) that for the same reason that proofs about the existence of God are hard. But, making proofs about the capabilities of the exact types of computation we currently use can still be interesting.
nojvek 1y ago
The way we build computers can’t simulate quantum fields. Just means our computers are limited. Doesn’t mean the universe isn’t a simulation. Everything you perceive is through the brain. Brain could be in a jar receiving the same neuron signals, it wouldn’t be able to know if it is in a simulation or not. There is no way for a program to know if it’s inside a virtual machine or not.
- f4uCL9dNSnQm 11mo ago
  There is no disagreement about that. But the simulation hypothesis claims that is is more likely that what we perceive as reality is a simulation, run by someone else, than that we are in "real" world. I think it is worse hypothesis than even Drake's equation - there, at least we know all factors, we just have no idea what their value is and with sample size of 1, the current uncertainly is like 40+ orders of magnitude. That still brings us closer to "is there inteligent life in universe" answer than we ever got with "is this universe a simulation".
ticulatedspline 1y ago
The universe is a simulation, question is whether we're running on original hardware or not. Seems at best they may have proved you can't simulate the universe on hardware that exists within this universe, which is a bit of a no-duh kinda thing. Imagine running a simulation in our universe and using a hardware random generator. And AI mathematicians inside your simulation proclaiming confidently that it would be impossible for them to be in a simulation because all randomness must be algorithmic and thus impossible to generate such randomness.
- xwolfi 11mo ago
  A simulation to what purpose ? What's the difference between a simulation and reality ? What is more "real" about the original hardware than about us ? It doesn't make obvious sense to waste such vast amount of energy for absolutely no purpose that we can observe: surely you could add a grain of doubt in your absolute statements no ? The universe is probably nothing very interesting, and reality depressingly obvious once we figure it out. It's like all these astrological sky maps they were doing to predict the mood of the gods above, before we realized we were a rock turning around an hydrogen ball, itself turning around the galactic center, completely non-special, like every other block of rock out there. Being in a simulation is just a way for you to replace god with a machine equivalent. You want a purpose, a father figure, an observer and a designer. Sadly, I think you and I are as precious as an ant, completely not part of any simulation, having no purpose and barely any effect on the universe. We're here because we could and we'll disappear because we must, with barely a blip, while everything in the universe is turning around senselessly.

30 points by dxs 1y ago

deleted 1y ago

[deleted]

Would be fascinating if true, but I'd be very curious what kind of model of "reality" they actually have. The paper itself [1] seems quite compact and extremely high level, so I'm sure some heavy hitters would try to reformulate it. Would be the most unintuitive thing to happen since Bell's theorem [2]. [1] https://jhap.du.ac.ir/article_488.html https://jhap.du.ac.ir/article_488.html [2] https://en.wikipedia.org/wiki/Bell%27s_theorem https://en.wikipedia.org/wiki/Bell%27s_theorem

karmakaze 1y ago

> "Therefore, no physically complete and consistent theory of everything can be derived from computation alone. [...]" It wasn't stated why all truths need to be provable though. Perhaps the paper goes into this detail that I'd like explained.

galaxyLogic 1y ago
I think you nailed it. There are true statements which cannot be proven, yes. But those could be true statements also in the simulated universe. The simulation does not need to calculate the correct ANSWER to every question.
- karmakaze 1y ago
  The incompleteness theorem doesn't even say that correct answers can't be computed, only that they can't be proven to be correct using the axioms of a consistent system.
  - galaxyLogic 1y ago
    Good point. But you can say there is always the question "Can this be proven with our rules of logic?" It's a curious thing, I wonder how to precisely define "proving without logic". Proof by "meta-thinking"?
theturtlemoves 11mo ago
Feels like the Halting Problem all over again...

ozb 1y ago

Almost every statement in this paper is wrong. The central claim in particular is not proven because a physical theory P need not be able to express statements like "there exists a number G, which, when interpreted as the text of a theory T, essentially states that the theory T itself is unprovable in the broader physical theory P" as an empirical physical fact.

NoahZuniga 1y ago
It's also very hard to verify the sources for some claims: I would expect the snag to be that many model theory results we have (Such as Gödel theorems) require quantifying over an infinite set, but that seems plausibly not possible to model in the physical universe. I quickly found this quote from the paper: > Arithmetic expressiveness; LQG can internally model the natural numbers with their basic operations. This is important as quantum gravity should reproduce calculations used for amplitudes, curvature scalars, entropy, etc in appropriate limits. Both string theory [34, 37] and LQG [35, 38] satisfy this by reproducing GR and QM in appropriate limits Here the citations are four entire books. How am I supposed to very that LQG can model N with that?
- roywiggins 11mo ago
  Here's a dumber argument: suppose you simulate a Newtonian universe in a computer. We do this at a coarse scale all the time. Now, suppose we dedicate a few percentage of solar output to this project and out pops functioning artificial life that can think more or less like we do. Such an "organism" would be able to discover Gödel incompleteness just as well, and thus eventually conclude via the same chain of logic as this paper that the simulation hypothesis is false. While inside a simulation. Sure, I'm assuming here that nothing Gödel's brain did is fundamentally non-computable, but that's a pretty easy lift I think. Math is hard but it's not that hard.
  - ozb 11mo ago
    For what it's worth, while I find this "obvious" as well, given the Church-Turing Thesis etc, Nobel Prize-winning physicist and philosopher Roger Penrose famously does think that human brains require access to non-computable insights to do math.

ralph84 1y ago

Even if they prove our universe can’t be simulated in a computer built the way we build them, how can they prove there aren’t other ways to build computers?

abemiller 1y ago
Yea I mean a more generic version of the simulation theory is just that there is an "outside world" within which our universe exists in containment. Seems probably impossible to disprove (or prove) that for the same reason that proofs about the existence of God are hard. But, making proofs about the capabilities of the exact types of computation we currently use can still be interesting.

nojvek 1y ago

The way we build computers can’t simulate quantum fields. Just means our computers are limited. Doesn’t mean the universe isn’t a simulation. Everything you perceive is through the brain. Brain could be in a jar receiving the same neuron signals, it wouldn’t be able to know if it is in a simulation or not. There is no way for a program to know if it’s inside a virtual machine or not.

f4uCL9dNSnQm 11mo ago
There is no disagreement about that. But the simulation hypothesis claims that is is more likely that what we perceive as reality is a simulation, run by someone else, than that we are in "real" world. I think it is worse hypothesis than even Drake's equation - there, at least we know all factors, we just have no idea what their value is and with sample size of 1, the current uncertainly is like 40+ orders of magnitude. That still brings us closer to "is there inteligent life in universe" answer than we ever got with "is this universe a simulation".

ticulatedspline 1y ago

The universe is a simulation, question is whether we're running on original hardware or not. Seems at best they may have proved you can't simulate the universe on hardware that exists within this universe, which is a bit of a no-duh kinda thing. Imagine running a simulation in our universe and using a hardware random generator. And AI mathematicians inside your simulation proclaiming confidently that it would be impossible for them to be in a simulation because all randomness must be algorithmic and thus impossible to generate such randomness.

xwolfi 11mo ago
A simulation to what purpose ? What's the difference between a simulation and reality ? What is more "real" about the original hardware than about us ? It doesn't make obvious sense to waste such vast amount of energy for absolutely no purpose that we can observe: surely you could add a grain of doubt in your absolute statements no ? The universe is probably nothing very interesting, and reality depressingly obvious once we figure it out. It's like all these astrological sky maps they were doing to predict the mood of the gods above, before we realized we were a rock turning around an hydrogen ball, itself turning around the galactic center, completely non-special, like every other block of rock out there. Being in a simulation is just a way for you to replace god with a machine equivalent. You want a purpose, a father figure, an observer and a designer. Sadly, I think you and I are as precious as an ant, completely not part of any simulation, having no purpose and barely any effect on the universe. We're here because we could and we'll disappear because we must, with barely a blip, while everything in the universe is turning around senselessly.