Yes it seems to be nonsense. Yes the universe has non algorithmic knowledge. All the universal constants and theories fall into that category. The speed of light is 2.99x10^8 m/s and constant in all reference frames. That's what it is. There's no algorithm to derive it. (Yes you can use other universal constants to get c but it's the same deal.)

Depends on what is being observed or tested. For example, if end-stage heat death is the experiment, a complete indexing of all possible heat sources would require more or less a complete simulation.

This.

The models we have of reality are based on observations and forming theories that attempt to describe the observations.

Our models are, by definition, models and not the reality itself.

Since the paper is only based on the models and not on reality itself (which it can't be since we don't have access to the real inner workings of reality, so to say the "source code of reality"), the paper cannot actually say anything about reality, only about our understanding of it.

And pretty much any physicist worth their salt will freely admit that our models and our understanding of reality are flawed and imperfect. They are good and good enough to be used for a ton of real-world applications, but they are far from perfect and physics is far from solved.

Yeah, the opening of the second paragraph on the page marked twelve basically says “we don’t have a true theory so we look at some proposals.” If anything, all it’s shown is that these specific proposals fall prey to the normal inability of mathematical systems to fully describe themselves, not that quantum gravity actively disproves a simulation. Everything after that might be sound if we trace all the sources. Nothing stood out as implausible or anything beyond some logical leaping. There was nothing that showed adding more to the system won’t fix the issues, which is the whole point of things like the updates their choice of set theory added to ZFC.

Stupid rebuttals for stupid ideas tbh. Simulation hypothesis should never have been taken seriously

I doubt the idea this can be proven at all. It makes the assumption that a simulation would have to function in a particular way. Why would that have to be the case? Anything you find could just be a quirk of the simulation. Hell, the simulation could be made in a universe with entirely different rules and logic, so you can't make assumptions about anything. It's really not something that I think could be disproven or proven.

(Because it can't be disproven or proven, and it doesn't change anything either way, you should live as if it isn't real probably. It's a fun thought experiment, but you probably shouldn't hold an active belief in it, because it seems like something that could mess with your mental health.)

Yeah, it seems all talk and no real substance.

I am also not a physicist nor a logician, just interested in the subject matter.

full of assertions not backed up by arguments

Can you provide some examples from the paper of assertions that aren't being backed up by arguments so I might try and look further into it? Thanks!

This article leads me to think their "proof" isn't proof at all, but I am curious as to why you think we couldn't be in a simulation?

That's exactly the sentence that made me pause. I could hook up an implementation of Conway's Game of Life to a Geiger counter near a radioisotope that randomly flipped squares based on detection events, and I think I'd have a non-algorithmic simulated universe. And I doubt any observer in that universe would be able to construct a coherent theory about why some squares seemingly randomly flip using only their own observations; you'd need to understand the underlying mechanics of the universe's implementation, how radioactive decay works for one, and those just wouldn't be available in-universe, the concept itself is inaccessible.

Makes me question the editors if the abstract can get away with that kind of claim. I've never heard of the Journal of Holography Applications in Physics, maybe they're just eager for splashy papers.

Yeah, there is no consensus on quantum gravity. There are competing theories, none of which have any viable path to test.

Here's the abstract from a paper from last year at https://arxiv.org/pdf/gr-qc/0601043 (PDF, unfortunately):

Freeman Dyson has questioned whether any conceivable experiment in the real universe can detect a single graviton. If not, is it meaningful to talk about gravitons as physical entities? We attempt to answer Dyson’s question and find it is possible concoct an idealized thought experiment capable of detecting one graviton; however, when anything remotely resembling realistic physics is taken into account, detection becomes impossible, indicating that Dyson’s conjecture is very likely true. We also point out several mistakes in the literature dealing with graviton detection and production.

Edit: That said, the paper does address this. They cover a variety of QG theories and try to address the fundamental requirements any theory must meet.

As we do not have a fully consistent theory of quantum gravity, several different axiomatic systems have been proposed to model quantum gravity Witten:1985cc ; Ziaeepour:2021ubo ; Faizal2024 ; bombelli1987spacetime ; Majid:2017bul ; DAriano:2016njq ; Arsiwalla:2021eao . In all these programs, it is assumed a candidate theory of quantum gravity is encoded as a computational formal system

ℱQ​G={ℒQ​G,ΣQ​G,ℛalg}.

It's over my head, personally.

We don't understand gravity to the point where we have a consistent algorithmic explanation for it. As suggested, there are competing theories, all of which are algorithmically based. The holy grail of modern physics is to find the algorithm that explains gravity as that is the last missing piece to finalize the theory of everything.

The results of this research are implying that it is not possible to prove, algorithmically, that gravity is quantum but rather that quantum gravity as the foundation of the universe is non-algorithmic and therefore non-computational. And so a theory of everything is impossible, implying that the universe cannot be simulated by computing the theory of everything.

This research builds on a lot of the work that Roger Penrose did in the 90s in exploring the potential non-algorithmic nature of consciousness (https://en.wikipedia.org/wiki/Roger_Penrose#Consciousness). If you read his book "Shadows of the Mind" published in 1993 you will find a prediction of future computational abilities that is a shockingly accurate description of AI deep fakes and the AI slop we see today with LLMs.

The no-simulated universe idea is one interesting conclusion of this research, but in my opinion, a more interesting conclusion of this research is that if you believe Penrose's argument for consciousness being non-algorithmic, than this research is implying that AGI is also impossible.

I'd point out that 'an observation event' is just hitting one thing with another thing, which is always going to have some kind of effect. And wave-particle duality is probably more of a spectrum than we give it credit for. Particles vibrate constantly and can be easily made to do wave-like things, like resonance. Collapsing a waveform into a particle may be less of a mode or type change and more like putting your finger on a resonating tuning fork.

I had this thought ever since i first heard about that in quantum physics that, it must be for resource optimisation.

Then what would the real world look like, huh?

But if we do discover we are in a simulation, totally hacking that computer...

This was my exact thought as well. There's really no reason why sufficiently advanced computers couldn't eventually simulate anything and everything. I'm going to go a bit off-topic but there's a theory about the simulation in The Matrix operating from a different set of laws from the real world. Hence the reason why humans can actually work as human batteries very efficiently compared to other forms of energy.

So, there's the possibility that if we are in a simulation then the "real world" might be operating by a different set of laws and physics to what we know in here. If that's the case then I really don't know where the limit actually is or how we could tell from inside here.

Also nothing that says the computers running the simulation have to behave the same as ours, or even that the laws of physics in the simulating universe have to be the same as ours.

All they proved is that we currently aren't capable of simulating our universe. Congrats guys, great science thanks for the contribution to human knowledge.

Yeah it seems more than likely that we will be able to make a universe in a computer and plug ourselves in one day. Which for me proves that it's possible that we already live in a simulated universe. Not likely or unlikely, but not impossible.

When you use the word simulated do you mean to imply intent? Or are you speaking to something that is computational in nature?

From skimming through the actual paper, it seems that quantum gravity is a theory of physics, more general than general relativity, where spacetime itself is something that's generated by a formal system of a formal language, a finite or small infinite set of axioms (fundamental physical laws) and rules for the creation of algorithms. What's seemingly proved in the paper is that there are theorems in this system which cannot be proven, because they are too complex. But theorems in this sense mean states of spacetime or energy or whatever, meaning that ultra-complex states cannot be modelled with this model. And allegedly these kinds of ultra-complex states occur in high-energy situations.

I'm not saying it's gospel but the article isn't as absurd as it first seems. Still I doubt this actually proves us not living in asimulation.

Is this what is called a finite-state-machine?

The repetition in the article itself makes me wonder if AI had a hand in the writing as well

unfortunately articles with images keep people reading longer and i doubt there are many "universe simulation" stock photos.

How?
Would not having any images change the article at all? Maybe photos of puppies and kittens would be better?

You did not evaluate it. Composition of your statements does not equate to original one. "It is true" and "it is unprovable" correspond to the whole sentence, you cannot just divide it in two parts.