They already have, as I said in response to your other version of the same question :)
Edit: Additionally the model seems very flexible. To the point that I’m unsure whether it’s surprising to be able to recover GR and other properties. I’m out of my depth here but given that string theory seems to face a similar problem of model selection have you looked at equivalences between those or does this not make sense in your eyes?
"However, once one has truly absorbed and internalized this realization, it leads to an exceedingly tantalizing possibility: that perhaps, lying somewhere out there in the computational universe, is the rule for our physical universe[2]. If an entity as remarkable as Rule 30 could be found just by an exhaustive search,then perhaps so too can a theory of fundamental physics.[3] The idea that there could exist some elementary computational rule[4] that successfully reproduces the entirety of the physical universe at first seems somewhat absurd, although there does not appear to be any fundamental reason (neither in physics, nor mathematics,nor philosophy) to presume that such a rule could not exist. Moreover, if there is even a remote possibility that such a rule could exist, then it’s slightly embarrassing for us not to be looking for it. The objective of the Wolfram Physics Project is to enact this search.[5]"
[0] There is in fact only one idea in that book, and this is that idea. But is this an original idea? When computer scientists and mathematicians come up with novel results in programming language theory or type theory (or whatever) what is to stop them claiming that they are empirically exploring a "computational universe"?
[1] Probably, but not to programmers, or the computationally literate.
[2] An extraordinary leap within the context of the introduction. Though note, neither is this an original idea, that the universe may be "digital" is not an idea original to Wolfram and it redates his magnum opus by I don't know how many years. Note there are actual physics projects that seek to kick the tyres this hypothesis.
Have you got that so far? A recasting in lofty terms of an unoriginal idea followed by a a giant leap to another unoriginal idea which serves only to motivate the project.
[3] So you say, but this is a giant non-sequitur.
[4] Why just one rule? And the rule hardly runs itself. What does it run on? Great you have a generalised term-rewriting system (how completely un-novel). "What rewrites the terms?* How is this not the first question you ask yourself?
[5] Hey, why not just say: “You know that "it from bit" idea? We have a hunch that term rewriting hypergraphs is the way to go. These are our explorations. We've encountered stuff that echoes contemporary physics.” Why not write the intro like that? Not grandiose enough for you?
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Any sufficiently worthy "it from bit" project must answer the following questions.
(1) Given that we know that any sufficiently powerful computing system can emulate any another what motivates your choosing this particular computational system and model?
(2) Demonstrate convincing physics (not toy models)
(3) Make testable predictions – this is not something for "down the line", this is what theories of anything must do. No predictions, no dice, no matter how nice.
(4) Is it software all the way down? If so, how? If not, what is the hardware and what does that imply?
(5) I would direct this last point at all TOE-heads like Wolfram and Weinstein and whoever. Why does it have to be simple? Why does it have to be elegant? Why is it always encoded in the formal systems you happen to play around with (geometry for Weinstein, term-rewriting systems / cellular automata for Wolfram).
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I think the wider scientific community needs to call time on savants like Weinstein and Wolfram.
Is a specific combination of rules not itself a rule? A lot of descriptions of Conway's Game of Life describe it as multiple rules, and other places refer to its whole setup as a "rule". Rule 30 is sometimes called a "rule set". I don't think there's a strict difference between a rule set and a rule, though the simpler rule(set) the better seems to be easy to agree on.
...
>(5) I would direct this last point at all TOE-heads like Wolfram and Weinstein and whoever. Why does it have to be simple? Why does it have to be elegant?
A theory with fewer free parameters is better than one with more. I think this extends to the complexity of the theory too: a theory with more rules (rule A applies to small stuff, rule B applies to big stuff, rule AB-patch applies to mediumish stuff) is worse than as a theory that explains the same stuff with fewer rules (a single rule X that naturally has A-behavior with small stuff and B-behavior with big stuff) in the same way a theory with more free parameters is worse than a theory with similar predictions and fewer free parameters.
It's Occam's Razor. Complex theories can have lots of different variants that each match the existing evidence but make different predictions in untested scenarios. Simpler theories have fewer variants that successfully match the existing evidence and tend to be more useful for making predictions, indicating that they match reality better.
>And the rule hardly runs itself. What does it run on? Great you have a generalised term-rewriting system (how completely un-novel). "What rewrites the terms?* How is this not the first question you ask yourself?
Is that not an obstacle for any theory? Tons of theories are meant to model what we see, without presuming some underlying mechanism. Newton came up with a theory of gravitation that modeled how objects tend to pull each other in without any idea of why nature chose for that to happen.
Even if the idea that not explaining what executes the rule of reality is a problem, then a simpler theory with fewer rules is obviously better because there's fewer unexplained rules.
>[5] Hey, why not just say: “You know that "it from bit" idea? We have a hunch that term rewriting hypergraphs is the way to go. These are our explorations. We've encountered stuff that echoes contemporary physics.” Why not write the intro like that? Not grandiose enough for you?
Personally, I found their intro to have a lot more background detail and motivation explained. Is your primary objection really that they were too grand for a few paragraphs?
>(1) Given that we know that any sufficiently powerful computing system can emulate any another what motivates your choosing this particular computational system and model?
Any system capable of having relativity and QM-like effects emerge out of it as described is interesting enough to study, even if it did end up having defects that meant it couldn't be a good model of reality overall.
I feel like you're treating this as if he's asking everyone to commit themselves fully to this model instead of to explore it.
>(5) I would direct this last point at all TOE-heads like Wolfram and Weinstein and whoever. Why does it have to be simple? Why does it have to be elegant? Why is it always encoded in the formal systems you happen to play around with (geometry for Weinstein, term-rewriting systems / cellular automata for Wolfram).
Presumably they chose those systems to play around to begin with because they believe those systems were promising.
Okay then. Why just one rule or rule set? I meant as much when I wrote what I wrote.
Why a tiny/simple initial starting state and one rule (or rule set). Sure, simple elegant formal systems are enticing to our brains but why assume that of our universe? Why not even try to explain why you feel this to be true? It's a pretty huge assumption in my eyes.
> A theory with fewer free parameters is better than one with more.
Sure. But the full statement is – the theory which is in best accordance with reality and with fewer free parameters is better. Starting from some entirely arbitrary simple formal system and working upwards and hoping you'll bump into reality along the way is very, shall we say, optimistic. And I do mean entirely arbitrary. Because you haven't motivated why this system rather than another this system is entirely arbitrary.
> Is that not an obstacle for any theory?
Yes, and with good reason. Because TOEs claim to be fundamental – how can they be fundamental if there's something underneath them so to speak. Which came first: the PC or Windows? Can't have one without the other.
> Personally, I found their intro to have a lot more background detail and motivation explained.
I didn't.
> Is your primary objection really that they were too grand for a few paragraphs?
I object to it on stylistic grounds and also, you know, I'll be the judge of the intellectual consequences of your theory. Lay out your theory and leave others hype it up if they so wish. (I'm so sorry if asking for a little intellectual humility is asking for too much these days. /s)
But mostly I object to the huge leap in their argument (as I said). It'd be nice for once if people like this were more honest that intuitively speaking there clearly are big gaps in their reasoning.
> I feel like you're treating this as if he's asking everyone to commit themselves fully to this model instead of to explore it.
Yes, that's exactly what I'm doing. Why should I explore it if you don't give me a compelling reason to explore it?
> Presumably they chose those systems to play around to begin with because they believe those systems were promising.
No. They chose the formal system they were familiar with.
And you skipped my whole part about making testable predictions. Which is a pretty big part.
If I want to read breathless computer science / physics / mathematics articles I've got Quanta Magazine for that: https://www.google.com/search?q=+%22fundamental%22+site%3Aww...
Honestly, I think this is a great way of describing what they're trying to do. I guess I think it's a little more realistic than you do: if our universe's physics could be described by a program on the order of tens of bits (I give an argument below for why we could expect that), then it's possible for us to come up with something like it from scratch by trying to construct a simple program that could have rich dynamics. If someone came up with a tiny model that happened to have physics emerge in it resembling our own, I'd be really interested to see how much we could learn from the model. They're trying to show that they happened to bump into interesting parts of relativity and quantum mechanics.
If they really did bump into relativity and QM from a simple system, then I think this is significant enough for more attention, even if they don't have any testable results yet, because it's possible that testable results will come from it. It might be that this model deeply resembles reality and we can flesh it out further, or it might just be that there is a class of models (that includes our physics) where relativity+QM arises (but not the rest of our physics, like the standard model), and we can learn about relativity and QM by studying models where the pair of them arise. Investigating this model is hard and it makes sense they want help.
> Sure, simple elegant formal systems are enticing to our brains but why assume that of our universe? Why not even try to explain why you feel this to be true? It's a pretty huge assumption in my eyes.
>Yes, and with good reason. Because TOEs claim to be fundamental – how can they be fundamental if there's something underneath them so to speak.
I've always imagined (and given the article's talk about "rule space", I think what Wolfram believes is something roughly similar) that the true-root TOE looks like the mathematical universe hypothesis / UDASSA (http://fennetic.net/irc/finney.org/~hal/udassa/) where in some sense, every possible computation exists, and they have measure (~the probability we find ourselves in it) inversely related to the length of information describing the computation (because if every possible computation existed, then every finite-length program would be instantiated infinite times by equivalent infinite-length programs with lots of ignored garbage code, and shorter programs would be instantiated proportionately more often).
From that, you would expect at large probability that our own universe's physics is described by the shortest possible program/rules that gives dynamics as rich as we see. If we imagined some universal computational language, it seems like specific cellular automata and hypergraph-rewrite systems could maybe be specified in tens of bits, so they're prime candidates for exploring. Even if those systems specifically aren't how reality works, then if they can produce dynamics about as rich as reality, then it implies that our reality's rules might be even shorter (or else we'd be more likely to exist in a cellular automata or hypergraph-rewriting system). At such short program lengths, the strategy of guess-and-check could be realistic, though the check part is really hard since we can't directly compute a significant number of timesteps, and instead have to try to reason about what large-scale patterns must emerge from the program.
(Wolfram specifically seems to believe that the hypergraph-rewriting system is universal enough to fill the role of the universal computational language, but I don't think that's strictly critical. As long as it's sufficiently simple to represent in whatever the root-TOE computes by, then it could be a candidate for our universe's physics. Hmm, I guess it would make sense that the way the root-TOE computes would have structure in common with whatever our universe's physics program is, because then our universe's program could be specified with fewer bits.)
So be it.