Whatever reality might be considered to involve -- mass, energy, entropy, time, whatever -- it's information that we actually consider in our minds.
In grade-school physics, it may be all too easy to confuse the map for the territory, because everything's just so simple that students might feel little compulsion to put much thought into things. But it's always been information.
If someone wants a string 2-meters long, they might measure out two lengths of 1-meter strings, then tie them together. If the result isn't close enough to 2-meters, then they might reason that they ought to be more precise -- they ought to better measure the 1-meter strings, consider the length-contraction due to tying the knot, and so forth. And then, they might think that there's a difference between the string and their information about it.
But further away, in more exotic contexts like in sub-atomic quantum-mechanical arenas or near black-holes, there might be less intuition about the things like strings -- folks may be pushing harder, working more heavily with information without a background sense of naturalness. Inferences may be drawn based on information, and then more built upon that information, until it seems like it's all information.
But, to be clear, this isn't some new quality of reality; it's how stuff's always worked. It's just how intellectual-computation works. It's just that, when things were simpler, folks didn't care to consider it.
That said, reality isn't quite "information"; it's just our perceptions of reality that're information. This is, reality's the territory, and our conceptions of it are the map. More involved computational-modeling just helps make that more apparent by undermining more naive modes of thinking about it.
I think there is an inversion here, though. The question implicit in this context is not whether the map is the territory, but whether the territory is the map. Now one can see these as homophonic statements, but is this the case? When is it or not?
"...In that Empire, the Art of Cartography attained such Perfection that the map of a
single Province occupied the entirety of a City, and the map of the Empire, the entirety
of a Province. In time, those Unconscionable Maps no longer satisfied, and the
Cartographers Guilds struck a Map of the Empire whose size was that of the Empire, and
which coincided point for point with it. The following Generations, who were not so
fond of the Study of Cartography as their Forebears had been, saw that that vast Map
was Useless, and not without some Pitilessness was it, that they delivered it up to the
Inclemencies of Sun and Winters. In the Deserts of the West, still today, there are
Tattered Ruins of that Map, inhabited by Animals and Beggars; in all the Land there is
no other Relic of the Disciplines of Geography."
I find it interesting that today we can very easily make a digital map of the world whose size would not only be the size of the world, but more so, much magnified to be larger than the size of the entire world.
It's only a few extra zoom levels from the standard zooms on the standard internet maps and in terms of data isn't that much more, as cartography is mainly about what you don't show than what you do.
To explain: Normally, folks grow up seeing the world through the lens of [realism](https://en.wikipedia.org/wiki/Philosophical_realism ): the belief that there's a "real world" being interacted-with. For example, if you see a table, then it's probably because there's a table -- in a true, objective sense.
You may have a friend also see the table. They may've perceived the table differently, having a slightly different notion of it. So, maybe you and your friend would have different "maps" -- though there's an objective-truth, the "territory", i.e. the concrete-existence of the table.
Realism can be compelling. For example, if someone denies that the table necessarily exists, you might feel inclined to pick up the table and hit them with it -- proof by demonstration! Or, should they continue to deny that the table exists, then clearly you didn't hit them with the table because there was no table to hit them with, and so you'd seem free-and-clear.
Except, the above-argument can fail. For example, what if you picked up the table to hit your friend with it in protest to your friend's denial that it exists -- and then, just as you're about to hit them, POOF! -- it disappears! Oh, wait, tables can't disappear... oh, blah, your alarm-clock's going off... weird dream, right? Okay, time for work.. wait, you're now waking up -- you were in an immersive VR-MMO that blocked your memories of the real-world, but apparently you were just playing a video-game. So the table was... a virtual-(dream-table), apparently. Except, wait.. you're coming to.. apparently you were in a coma, just imagining a VR-MMO in which you were dreaming. Except it turns out that you weren't in a coma, but rather just suspended as you entered Heaven -- and, by the way, Earth was sort of a virtual-testing-ground for AI before letting them into Heaven (and, also, you're an AI -- but then who isn't?). Hah, JK -- all of that was just a really trippy dream! Time to sit down infront of your actual, REAL table that totally couldn't possibly be a complex illusion created by the advanced alien-race that's studying you in their zoo (don't worry, they'll use force-fields to levitate anything you try to place on the totally-real table).
In the above paragraph, we referenced a few different things not normally taken seriously in Realism: dreams, coma-like-fictions, cognitive-alterations, deities, advanced-aliens trolling people, etc.. Realism is obviously incomplete if we allow that any of those things might apply to the current-moment, but if we just decide to ignore those possibilities, realism's fine, right?
Now it's science time! Huh, weird.. turns out that there're particles, e.g. neutrinos, that can go through the table. So maybe it's not solid -- but it's still there, right?
Except, there's General-Relativity apparently denying that there's an objective, universal time. So apparently the table doesn't exist with you in precisely the same moment of time.. in fact, it may be somewhat unclear if there's even a good notion of what it'd mean for the table to co-exist with you at the exact same point-in-time.. but.. let's ignore that.
Then there's quantum-mechanics.. apparently the table might quantum-tunnel outside, such that it's not actually there. ..or is it, just it's a delocalized thing? Except energy's not really conserved, so.. if we allow for delocalization, would it necessarily be a "thing" if it could actually just be nothing and disappear?
Now, if you ask a physicist how likely a large, human-scale object (like a table) would be to spontaneously disappear, they might not bother even trying to estimate the figure beyond just saying that it's basically zero. In fact, to quote the abstract of [this paper (2020-06-01)](https://www.nature.com/articles/s42005-020-0371-x ):
> Quantum tunnelling is a phenomenon of non-equilibrium quantum dynamics and its detailed process is largely unexplored.
Even after consideration of the above, would a person necessarily feel that reality-isn't-real?
I'd speculate that Realism can make so much sense because it seems to work so often. For example, if you try to reach out to that table, perhaps you'd find your expectation that it'ld be solid justified. Perhaps you'll predict various things under the hypothesis that it's real, and perhaps you'll find yourself consistently correct.
This is, Realism seems defensible in every-day experience where we can keep testing it and it keeps working. And if it's simple-and-reliable, what's not to love? Why yield to weird, speculative-sounding non-realist arguments?
But for scientists working at the boundaries, there're frequently things discussed that may turn out to be phantasmal. For example, the dark-matter -- folks discuss it as though it's real, but if it's not.. then what? Or what about particle-physics, where folks are looking for new particles: if there seems to be a new particle, but it's not verified yet despite possibly having seen it many times, how does a realist handle that? Or, in Chemistry, what's the enthalpy of some mixture -- if it depends on the model, how can it have a precise value?
> I think there is an inversion here, though. The question implicit in this context is not whether the map is the territory, but whether the territory is the map. Now one can see these as homophonic statements, but is this the case? When is it or not?
In the domain of Realism -- when things are simple and near-human -- the map (cognition) might be mistaken for the territory (reality). But even in Realism, folks might tend to accept that that's a simplification of a situation; that the reverse doesn't really hold except as a simplification.
However, if Realism is rejected in favor of a more general perspective, then the notion of reality (the territory) is lost. It becomes more about maps of other maps. Folks might even recognize themself as unknowable and their cognition as potentially flawed, denying certainty on just about anything.
Then it's "non-realism" because we simply stop talking about reality. ..kinda -- taking that too naively can lead to all sorts of absurdities (https://www.smbc-comics.com/comic/2010-09-08 ).
---
It's hard to really talk about this stuff at any decent level -- stuff gets so weird that conceptual-correspondence is lost over time, making it difficult to discuss non-trivial things. So, instead, try to lay a conceptual-foundation that might be built from. Sorta like telling kids that the Earth circles Sol -- it's kind of a starting place.
But to try to answer the question directly: there's not really a solid territory to be a map, unless you're considering something cognitively-local, at which limit it might seem like a practical-fiction. At the most extreme, territory becomes the map when it's part of the mind -- the thing that a mind might most convincingly claim to know to be real (https://en.wikipedia.org/wiki/Cogito,_ergo_sum ).
---
Alternative perspective, for a scientific-mind who'd tend to favor Realism:
Let's get back to Earth -- it's 2022 on Earth. We're talking about the real-world: no dreams, aliens, whatever. Reality is simple, clean, and objective. In fact, tomorrow, physicists will announce that they've disproven modern-theories and the world's actually purely Newtonian afterall.
We'll keep advancing AI. We'll make a huge super-cloud-computer (or whatever) that'll host many AI-minds in a virtual-world (like an MMORPG, but more realistic for the AI's; they'll have avatars as bodies and believe their world real).
We'll try to implement realistic-physics. But we might do some lazy-evaluation; we might not fully compute some stuff until it's relevant, at which time we might go back and calculate it. We might fill in the gaps with random-values.
We might make it weird. For example, if we're interested in what's happening in one part of the virtual-world, we might invent some sort of de-coupling to approximately break it off from other parts. Then we can devote our computational-power to simulating what we're interested in; we can back-calculate other stuff later. Perhaps artifacts that the in-world-AI might become suspicious of, but as long as we keep it realistic enough, probably fine.
The AI, themselves, are part of the world -- their neural-networks are also simulated in the world itself. So if we freeze part of the world, we freeze the AI there too. If we fudge part of the world, then we fudge the AI too.
So, obviously, those of us on Earth are real, and Realism is obviously correct. But for the AI in our simulation, what would they be correct to believe?
Then, if an AI's mind contains a mental-proxy for something they observed in their virtual-world -- what of that's "information" vs. "reality"?
---
PS: I realize that last bit may seem to offer two different models for reality: naive-realism vs. we're-AI-in-a-simulation. To avoid that, I just wanted to be clear that neither of those models is even close to being correct. They're both just toy-models to consider.
All matter is information, all information is functional, and perception is therefore the lazy evaluation of the universe.
(in the Greg Egan edition of this thesis, the speed of light emerges as a property of evaluative propagation through a functional universe, and new forms of consciousness are encountered living within the Lisp machine of the cosmos)
Our universe is a busy beaver program. The longest running BB programs are self-modifying. Any program that reserves static areas necessarily loses out on potential runtime.
> [matter-antimatter annihilation] converts all the mass of the annihilating particles into energy, typically gamma photons. However, if the particles do contain information, then this also needs to be conserved upon annihilation, producing some lower-energy photons. In the present study, I predicted the exact energy of the infrared red photons resulting from this information erasure, and I gave a detailed protocol for the experimental testing involving the electron-positron annihilation process.
Looking at the paper linked to in the article[1], I'm having a hard time not dismissing this immediately. There are several implications to this theory:
- Information has mass.
- Information cannot exist at absolute zero.
Does this mean that bringing a hard drive to absolute zero changes its mass and erases its contents? Does the information somehow come back after the drive is warmed up? Also there are many ways to represent information: magnetic charges on a spinning platter, electrical charges in SSDs, physical impressions on metal, graphite on paper, etc. Do all of these get destroyed at absolute zero? I don't know how that's reconcilable with the rest of physics.
Former mathematical physicist here. I haven't read the article yet so don't take this comment as a defense nor as a rebuttal, but I just want to point out that your reasons for immediate dismissal are not obviously valid.
- The Bekenstein-Hawking black hole entropy directly relates information to entropy. There has been an "it from bit" program (and more recently "it from qubit") dating back decades that tries to treat information as somehow fundamental with matter/energy emergent. The jury is still out, but I wouldn't consider it to be particularly controversial (at least not moreso than other speculative theoretical physics).
- To me it seems absolutely physically plausible that cooling a hard drive to absolute zero would destroy its contents. As another example, you can destroy the information contained in DNA at much warmer temperatures than absolute zero. Why would heating it back up restore the information? Most thermodynamic processes are irreversible. And by the way, thermodynamic irreversibility is related to entropy change, which is a measure of information lost.
> To me it seems absolutely physically plausible that cooling a hard drive to absolute zero would destroy its contents.
Cool, cool. It doesn't, but enjoy.
Why would you imagine this would happen? The magnetic domain is not affected thus, and neither are MOSFETs.
You're a mathematical physicist? You're the single least likely person on Earth in my imagine to say "oh, you reduced the speed of some atoms? That must mean magic happens."
What could possibly wipe a hard drive from the action of cooling it down?
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> Why would heating it back up restore the information?
In short form "it doesn't."
You may be confusing that some heating processes create damage with the idea that warming something up will harm it.
As any schoolchild can tell you, DNA has survived billions of years on this planet, being heated and cooled somewhat rapidly throughout.
> And by the way, thermodynamic irreversibility is related to entropy change, which is a measure of information lost.
This is a very "consider a spherical cow" approach to physics.
The reason physicists are made fun of on those grounds is that the abstractions they bring to the discussion are frequently so far divorced from the real world situation that by the time you start bringing the real world back to the discussion, their abstractions fall apart.
Real world objects that were not designed for durability have not suffered this damage on the timescale of a fifth of the length of the universe.
That things are irreversible and related to one another isn't much use when you look at the real world and the things you're describing aren't actually happening at large scale, even in uncontrolled natural conditions.
An insect that's been in amber for 500 million years typically has DNA loss on the order of ~5%. It has been exposed to a wild range of temperatures.
If you genuinely believe that exposing a hard drive to absolute zero would destroy it, help us understand why Voyager is still running.
Maybe it's because it's still a tenth of a degree kelvin above absolute, or something?
There's a huge difference between exactly zero and close to it. Space isn't even that close compared to what's been done in a lab, and even in lab experiments the temperatures involved don't correspond to such effects happening.
Indeed, it's a purely theoretical scenario, and I don't think anyone is claiming otherwise: the paper simply notes that one consequence of the theory is that information cannot exist at absolute zero, and then someone who considers this weird questions what would happen to an object storing data were this to happen. Your response was 'nothing, because data storage on space probes still works', which is a non-sequitar: the theory does not predict that data storage at space temperatures will cease to hold information.
But one specific mechanism exists: at a certain point there's entropy in simply the structure of the macroscopic object which prevents lowering its temperature further. So if you were to cool it as close to absolute zero as possible it would require turning it into something which was not a hard drive (again, this is something would occur far below the current achieved temperatures with even microscopic objects).
Theory says that this scenario cannot occur, so it's actually not a theoretical scenario.
Temperature is defined as the brownian net motion of a bag of particles. No reference point is involved.
How do you make that zero temperature? Are these particles zero-motion with respect to themselves? Then they aren't with respect to the planet, or the sun, or the galaxy.
Are they zero-motion with respect to the sun? Then they're hot enough to melt in seconds.
The conceptual idea of zero-temperature is not a real thing.
These people doing their fake-wise "but weird things happen at zero temperature" are just snake oil salesmen plying false knowledge.
There is no such thing as zero temperature.
In the meantime, there's nothing theoretical about the practical scenario, either. Voyager's hard drives have been in the absolute zero of outer space for more than half a century. Its heater, which did not reach the hard drives, has been off for more than a decade.
Those hard drives have been sub-1-kelvin for years and nothing changed.
These people are trying to speculate about what would happen if in a situation we've already had a dozen times, because they don't know the truth, and are filling their lack of knowledge with guesswork.
When it's presented to them that facts exist, they attempt to move the goalpost to theoretical limits which physics says aren't actually real at all, and then from there try to lean on their depth in physics.
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> So if you were to cool it as close to absolute zero as possible it would require turning it into something which was not a hard drive
This is a fantastic point, and something I hadn't even thought of.
I like this a lot.
I'm still wondering about "what, you think ball bearings in a vacuum don't work when it's chilly?"
Like I can't even think of why they think it'll fail, except some magical belief that the fact that it's cold just causes magical breakage
The operation of the damn drive is friction based. It'll heat up! Crimeny.
I'm mostly done with this conversation, but I'll note that space is not as cold as you're thinking: The coldest that voyager is gonna get in the next million years is 2.7K (thanks to the cosmic background radiation this is the equilibrium temperature of any object in deep space), not sub-1K, and it's a lot warmer than that now, latest report is about 200K (though that's about 8 years ago). It also doesn't have hard drives, though this is a pedantic point because it does use another form of magnetic storage. You're talking about a 'practical scenario' which is so far away from the theory being discussed it's completely and utterly irrelevant, like if you were talking about the temperature of the sun it'd make little difference in how much hotter you're talking relative to the relevant temperatures.
You seem very arrogant discussing things that are purely theoretical (absolute zero objects). A healthy debate includes space for speculation, and you are shooting this speculation down with arguments like ”it just doesn’t work like that”, which does not bring anything to the discussion.
When people are speculating that effects will happen, even though we've done this and they didn't, by asserting that an impossible goal wasn't reached, it's appropriate to ask them how.
If you feel that it's appropriate to use emotive words like "arrogant" when someone says "please tell me how that's possible," then I guess I'm not that worried about your opinion.
We can get close enough to absolute zero that very weird quantum effects being to happen which one could argue are associated with information loss.
Cooper pairs is one such example, where at very low temperatures electrons pair up and begin to behave like a new combined particle with integer spin. Thus they morph from fermions to bosons which are no longer subject to pauli exclusion and can all occupy the same state. The information required to describe such a system decreases substantially as the potential state space is now quite limited.
This manifests in physical phenomenon like superconductivity and superfluidity.
I will repeat my protest which you ignored from the previous comment.
1) We have never reduced even a single atom to absolute zero. Practicioners debate whether it's actually possible.
2) Your discussion of bose-einstein condensates is neat and all, but the explicit context is a hard drive. Nobody has ever condensed a macroscopic object (the breathless article about condensing a tardigrade isn't actually correct.)
There has never been a superfluid or superconductive hard drive.
Please focus on the question being asked, in the context being asked, if you must reply.
How do you propose to reduce a hard drive to actual non-almost zero degrees? Not a few particles, not electron pairs. A hard drive.
Once it's at absolute zero, formally, so what? Yes, I saw you guys handwaving "spooky stuff happens," but in reality, we've had hard drives within a tenth of a degree kelvin and nothing happened.
If you're going to propose effects, please have a specific mechanism in hand that creates the specific effects asked about, in a context that is the hard drive and not two electrons
The CERN CMS magnet is a 10,000 ton superconductor. 6-meter diameter and 13-meters long.
For the vast majority of materials (of any size), strange things do happen when you hit the critical temperature. You can take any amount of mercury for example and when it hits 4.1 K it loses all its electrical resistance.
Hard drives are not the only items that can contain information.
Correct. The current zero point energy is believed to be a false vacuum (local minimum). One of the end-of-the-universe scenarios involve it tunelling to a lower state (bubble nucleation). Things become progressively more dire the lower the energy of the next (false or real) vaccum is, including matter and gravity ceasing to exist. Not only does this sound a lot like "no information at absolute zero," it is also a terrifying existential crisis (you're welcome).
Well I understand that information, like energy, cannot be destroyed (hence Hawking radiation) so it couldn't just be reduced to zero, it'd have to be transformed. Also the parent's argument about freezing and then reheating to destroy and restore information is a good one because that would be reversing entropy in a closed system (assuming the info was indeed destroyed) and thus impossible.
IANA physicist though, just a lay person with an interest in information theory.
According to the paper, the amount of information that can be stored decreases as one gets closer to absolute zero. Our current information storage technologies and refrigeration technologies don't let us actually test this, but with a high enough information density and a low enough temperature, one should expect to lose information if this theory were true.
The connection between information entropy and thermodynamics entropy is pretty well established, as well as theories which relate the destruction of information to irreversability. This part of the article is actually not particularly controversial. The idea of a storage device gaining some mass when information in placed on it is not particularly new, but it is something which would be extremely difficult to measure. In terms of the question of absolute zero, you have to consider that the physical reality of a system at zero temperature (truely zero, not femtokelvin) and thus zero entropy is extremely weird: it would basically require a perfect crystal lattice extending infinitely in all directions. This is one of the reasons why it can't be reached. So the answer is basically that if you were to cool a hard disk to absolute zero (which is impossible), it would first require turning it into something not recognisable as a hard disk. (And if you're thinking we've come close to absolute zero in experiments, remember that the difference in scales between thermodynamic information/entropy and other information (even the information contained in the shape of a solid object, let alone any amount of information our current technology could store) is incredibly vast: the temperatures reached in labs don't really come close to that.
So while this is still basically a theoretical idea (and likely will stay that way for some time without a very clever experimental design and a lot of resources: notice they basically propose building a LIGO to perform their experiment), it's not as weird as you might think, and the ways in which it is apparently weird reflect a weirdness that is already present in thermodynamics.
First, worth clarifying that "information" can be misleading because it sounds like a very general term. For example, it may sound like it implies that there's some underlying super-reality that requires ~1.509 bits to model an electron. Which isn't (generally) the case.
Instead, "information" in that context often refers to how much information humans estimate that they could record using some amount of energy -- or, various things like that (depending on the model).
Mass can warp reality -- such as through gravity, and as noted with relativistic-effects. And apparently energy counts toward mass (e.g., the E=mc^2 thing), where adding energy to a system adds mass to it, affecting its gravity.
So, if energy and mass are linked, and energy and information are linked, then is information linked to mass? For example, would a sufficient amount of information-density create a black-hole? Kinda like an informational-[energy-based black-hole](https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics) )
That's kinda how they appear to be considering it.
That number is an average number of bits per elementary particle. I presume that information can be found not only in particles, but also in how they're arranged.
On the other hand, information need not come in whole bits: there are three quark "colors." Storing the color of a quark takes, what, 1.5 bits on average?
> Since every particle is supposed to contain information, which supposedly has its own mass, then that information has to go somewhere when the particle is annihilated. In this case, the information should be converted into low-energy infrared photons.
How does this compare to the very very low amount of heat released when a bit is erased under Landauer's principle? How many bits does a particle store? Does it store its location? Does the number of bits needed to store that depend on a choice of units, frame of reference, and resolution?
A couple of questions from someone struggling to put this in more relatable terms:
Isn't information in theoretical physics just mean something that repeats, or perhaps relatable, in some way - for example an underlying structure similar to other structures - and in that sense is measurable information another form of describing mass/energy, like moving between frequency and time domain in signals? (side note: could the significance of information be a by product of using math to describe physics, as math can only describe properties of repeating systems, so high information is equilivant to being easily captured in mathematical terms)
And on his experiment, assuming his theory is correct - why would a hard drive represent "pure data", such that writing to it would constitute adding an exact measure of information to mass? For example, in an erased state the drive would have ambient information from surrounding electrical fields, is there some mechanism to erase the drive that ensures it lacks any information? And why would data that a computer can read not be inefficient in some way and contain information irrelevant to the hard drives usage, causing it to measure higher even if this exact mass of information is correct? The weights seem so small that even the smallest bit of environmental interference would make this experiment fail.
My pet hypothesis is that information is the wave, and particles are just particles. For example, the information about an entangled pair propagates at (or above) the speed of light the instant that they are created. Therefore, the shared state would already be determined at the place of measurement.
Also, wouldn't a full hard drive weight less than an empty one (unless "empty" means initialized to all zeroes)?
Either this uses the word "information" in a way that is 99% divorced from common usage or the philosophical implications of this are massive. It would essentially mean that truth or falsity is an inherent property of the universe. Is this string gibberish or is it information? Might even change cryptography forever, too
The reality of information is pretty well accepted. Take the black hole information paradox for example, which observes that 1. Hawking radiation means that black holes eventually evaporate, and 2. information about the infalling matter cannot be destroyed, so where does the information go after the black hole is evaporated? This study proposes a different way to test the reality of information that is a bit more... experimentally accessible than an event horizon.
How could this possibly be a "state of matter" ("the fifth" in contrast to sold, liquid, gas and plasma, the standard four)? Entropy and information are qualities which all states of matter have.
And Information as a quality of matter is already taken into account by a variety of physical theories - none of which label information a "state of matter"?
The theory is saying that energy (or mass) can be converted to information and that it isn't a quality of matter.
How could possibly be? Information is an arrangement of elements - the elements are normally matter, what else would they be? Oppositely, how could you have matter without information? Matter and energy are characterized by multiple states, which is what allows and forces them to carry information.
You should read the paper. The conjecture seems to be that arrangements of particles of lower information entropy are more massive than those which do not. Weird? Yes. More weird than the weirdest aspects of quantum mechanics? Not in my opinion.
You should read the paper. The conjecture seems to be that arrangements of particles of lower information entropy are more massive than those which do not.
My time is limited. You haven't given any reason why this isn't incoherent Malarkey and I've given some good reason imo why it is.
Sure, spew out random balderdash and then point to some unusual pattern somewhere and say "see that proves it".
HN used to be good in the sense of having skepticism to everything. Now someone has found some formula that can push idiocy to the front page.
>My time is limited. You haven't given any reason why this isn't incoherent Malarkey
You don't _have_ to read or understand everything. It's fairly evident that this is an article in the field of theoretical physics, and as such assumes certain understanding of the current thinking in the field.
Now, I'm not an physicist, and I can't personally judge the underlying paper. _Especially_ because of this, I'm careful not to immediately dismiss this as "incoherent Malarkey" and "random balderdash". I like seeing this type of content on HN in the off-chance someone who _does_ know more can chip in their thoughts.
Having said all this, what the paper proposes is not entirely inconceivable on its face. It's reasonably accepted in Quantum Mechanics that there's something special about "information" [0][1], so who knows? Maybe there's something here.
Uh, I just read the paper and am trying to explain what’s in it to you. I don’t have a strong opinion about the conjecture’s validity. In the time it took you to ask basic questions you could have read it.
This is a point of view originating from physics to look at the world and combining with information theory. I think it's more likely the other way round: information/patterns dictate how particles are structured and their interactions. This goes for energy as well.
For something to exist, it has to be observed.
For something to exist, it has to have a position in time and space.
And this explains why nine-tenths of the mass of the universe is unaccounted for.
Nine-tenths of the universe is the knowledge of the position and direction of everything in the other tenth. Every atom has its biography, every star its file, every chemical exchange its equivalent of the inspector with a clipboard. It is unaccounted for because it is doing the accounting for the rest of it, and you cannot see the back of your own head. (except in very small universes).
Nine-tenths of the universe, in fact, is the _paperwork_.
When studying physics (simple stuff like electromagnetism and gravitational forces) I always wondered how the universe "knows" what's the distance between two planets when it comes to calculating forces amongst them. If the data (the distance) actually exist, where is it stored? Is it perhaps calculated "on the fly" so it doesn't need to be "stored"?
Totally sure that's not how it works in real life, but for us humans, that model is the best theory we have so far, so it's difficult to think differently.
Good question; I think the answer from general relativity is that it doesn't, and that those changes are propagated out locally at the speed of light. So it's a Newtonian fudge to have variables like "distance between two bodies" in the equations.
Mass changes spacetime curvature, and spacetime curvature pushes masses around, back and forth in a grand dance!
I definitely don't know much about general relativity, but isn't it yet another model/theory? A better one I bet, but one that still relies on information, so when we talk about "mass changes spacetime...", well my question remains: "how does the universe know, for instance, the mass of the sun in order for the universe to allow the deformation of spacetime that the sun causes?" I know it's probably not a rational question, but I used to ask that question to myself when I was a student.
Moving to a field theoretic model is precisely what allows you to abstract away at least some of those questions.
Space-time is distorted by energy, rather than just mass, which reduces the number of things the universe has to be prescient to. We can further eliminate some more prescience, by thinking in terms of density rather than mass: The laws of physics stated locally require only (say) a number and a field, rather than a pesky integral.
"Space tells matter how to move,
Matter tells space how to curve"
And asking these questions is a good thing. I've been sitting down and really thinking about special relativity recently, it's fun going through old papers and seeing about how to
derive the algebra in the most smugly experiment-less way.
On of the (self-admitted) flaws in Newton's conception of gravity is that it's in terms of forces (or potentials) that act across large distances; it's part of his "hypotheses non fingo".
One of the philosophically more pleasing things about GR is that it is local. But, of course, Newton's conception is a small-mass / low-velocity limit, so how can that be?
GR says that the effect of stress/energy at a place x changes the metric at that place. But the metric is something made of derivatives, so the space in some small neighborhood (this is the local part) nearby gets deformed. That deformation is itself a form of stress, and so places in the neighborhood of x effect places THEIR neighborhoods and so on.
So there's nothing built-in that's long-distance. Big long-distance effects are built up out of everybody talking to their immediate neighbors.
When studying electronics I fell down the rabbit hole. Electricity and magnetism are inseparable. I knew of EMF but why did magnetism push something, where did the magnetism come from, what are domains, how is magnetism emitted from domains, how are the atoms involved, what are virtual particles...and so on.
When really as an electronics technican all I needed to know was magnets can move things.
My understanding is probably also incorrect / incomplete, but I use the "trampoline" mental model where objects on the medium both update and react too the local geometry, ex. a tennis ball will roll towards the bowling ball, but doesn't "know" about the bowling ball.
Though it begs the question _how_ a given particle has read/write privileges with the geometry.
interesting, this feels quite close to verlinde's entropic gravity theory, that "gravity is a consequence of the "information associated with the positions of material bodies" (https://en.wikipedia.org/wiki/Entropic_gravity)
> "A map is not the territory"
Whatever reality might be considered to involve -- mass, energy, entropy, time, whatever -- it's information that we actually consider in our minds.
In grade-school physics, it may be all too easy to confuse the map for the territory, because everything's just so simple that students might feel little compulsion to put much thought into things. But it's always been information.
If someone wants a string 2-meters long, they might measure out two lengths of 1-meter strings, then tie them together. If the result isn't close enough to 2-meters, then they might reason that they ought to be more precise -- they ought to better measure the 1-meter strings, consider the length-contraction due to tying the knot, and so forth. And then, they might think that there's a difference between the string and their information about it.
But further away, in more exotic contexts like in sub-atomic quantum-mechanical arenas or near black-holes, there might be less intuition about the things like strings -- folks may be pushing harder, working more heavily with information without a background sense of naturalness. Inferences may be drawn based on information, and then more built upon that information, until it seems like it's all information.
But, to be clear, this isn't some new quality of reality; it's how stuff's always worked. It's just how intellectual-computation works. It's just that, when things were simpler, folks didn't care to consider it.
That said, reality isn't quite "information"; it's just our perceptions of reality that're information. This is, reality's the territory, and our conceptions of it are the map. More involved computational-modeling just helps make that more apparent by undermining more naive modes of thinking about it.