Information as the key underlying physical principle

[Feeble Wonk]

If there is information, it is information about something. Else, I would not name it information. So, information IMHO presupposes the existence of something, else it would be meaningless. Thus, it is something derived from real existence. So, "bit is about it", which makes "it from bit" circular.
Moreover, information is always stored in something which really exists. This storage is, of course, something completely different than what the information is about. The nice pictures on the stick are usually not pictures of the stick. But, nonetheless, this is a second direction where the bit is impossible without a preexisting it.And this reality is what I miss in the "it from bit" concept.

Precisely IIja! This is exactly the discussion I was hoping for. This seems to be the intuitively obvious position that I've always believed myself.
Yet, I struggle with being able to conceptualize an objective, substantive "it" that is consistent with the physical action described by quantum physics (at least to the feeble degree that I understand it).

So, again, I was hoping for atyy to clarify what he meant by his statement that "information" is "physical".

 

[Feeble Wonk]

But perhaps one should also remember that "information is physical" :)

I don't mean to press, but I know that your posting on multiple threads which take your attention. So I just wanted to bump this thread in hopes that you would take a little time to explain what you meant.

The definition of *physical* (other than the biological meanings) according to dictionary.reference.com is..."of or relating to that which is material:
the physical universe; the physical sciences."

The freedictionary.com is slightly more inclusive, offering two (nonbiological) definitions that might apply... "3. Of or relating to material things: a wall that formed a physical barrier; the physical environment.
4. Of or relating to matter and energy or the sciences dealing with them, especially physics."

All of these refer to "material" existence with respect to being something *physical*. In what manner do you view information as being physical.

 

[Paulibus]

I suspect that there is an elephant in this particular room, namely the distinction between what we are and what we do.

Just as an elephant is an animal, so are we. And, although elephants do communicate well enough for elephant purposes, we excel in this respect -- as in this interesting thread --- having invented various languages to serve the human purpose of exchanging 'information'. But a language, even quantitative mathematics, is only a mental construct; not something as physical as say, a brick, despite the way we physically represent it as 'squiggles on paper' or binary bits.

That's why I also

... struggle with the conceptualization of physical existence (as) consisting of only information.

. Could this concept be just a bit of human foolishness?

 

[friend]

If there is information, it is information about something. ...
Moreover, information is always stored in something which really exists.

But the basis of matter is the quantum mechanical wave function, which seems to be a probabilistic creature by nature. So it seems the basis of reality is probabilistic. What is the wavefunction a distribution of, if not pure possibility from which we get information?

 

[Feeble Wonk]

Just as an elephant is an animal, so are we. And, although elephants do communicate well enough for elephant purposes, we excel in this respect -- as in this interesting thread --- having invented various languages to serve the human purpose of exchanging 'information'. But a language, even quantitative mathematics, is only a mental construct; not something as physical as say, a brick, despite the way we physically represent it as 'squiggles on paper' or binary bits.

Very well written Paulibus. I would agree that, intuitively, the assertion that information (and only information) is the fundamental essence of *physical* existence would appear on its face to be utter "human foolishness".
Yet, having said that, I'd also suggest that there is a fundamental difference between human spoken/written language, which is a human creation, and quantitative mathematics, which is not. I've often heard it said that Newton and/or Leibniz created "The Calculus". But that's sheer silliness. It's like claiming that some ancient pebble pusher created "The Addition"... as if 2+2 had not equaled 4 prior to that. At best, Newton and/or Leibniz "discovered" calculus. Or you could say that they developed the mathematical "language" to manipulate the formulas that represent the underlying mathematics itself. However, the logical and quantitative relationships expressed by the mathematical "language" simply are what the are because they are what they are. That self referential consistency, which appears to be reflected in nature, gives me sufficient pause to not reflexively give into my intuitive inclinations.

 

[Paulibus]

I'm afraid I agree with the ancient pebble pusher. Even at the risk of being thought silly , I resist the proposition that two and two make four can be characterised as some sort of eternal truth, and prefer to think of calculus as an evolved and heroic human invention; certainly not as a complex of discoveries. When I walk in the woods I don't expect an abstract descriptive label like a number to jump out of a bush and bite my leg, as it were. I maintain that abstractions are invented, however cleverly, and not discovered; and that it's only long familiarity that tempts us to confuse abstract concepts with real things. Perhaps a matrix is more easily recognised as an abstraction than a counting number formula? I see mathematical language not as compendium of relationships that 'simply are what they are because they are what they are', but as a human construct that wonderfully serves to usefully describe the physical situation we find ourselves in. Viva mathematics, viva!

 

[Feeble Wonk]

I see mathematical language not as compendium of relationships that 'simply are what they are because they are what they are', but as a human construct that wonderfully serves to usefully describe the physical situation we find ourselves in. Viva mathematics, viva!

I certainly didn't mean to belittle the accomplishments of mathematicians throughout history. On the contrary, advanced mathematics, particularly its application in the physical sciences, would have to be considered one of the pinnacles of human intellectual achievement.
Yet, as miraculous as that achievement is, it still seems to me that what they have done is to recognize, decipher and manipulate the extant mathematical patterns, not create them. Can you tell me that the ancient brute, before our pebble pusher, when holding two rocks in one hand and two in the other was not holding four rocks?

 

[Paulibus]

Again, what we actually are (walking, talking, and now writing primates) is key here. We describe what matters to us because we can. In your example the ancient brute created a four-rock pattern which you so described with the help of the extant language of arithmetic; an ancient abstract , human construct, not an eternal truth that always existed to be recognised. Mathematics is revered because it has a predictive and therefore verifiable character, which helps amazingly with living, prospering and surviving in this physically complex universe, so strangely equipped with past, present and future. But I think that mathematical patterns are 'only' intangible constructs of our minds, rather than tangible realities. As they say in France, à chacun son goût .

 

[marcus]

I suspect that there is an elephant in this particular room, namely the distinction between what we are and what we do.

Just as an elephant is an animal, so are we. And, although elephants do communicate well enough for elephant purposes, we excel in this respect -- as in this interesting thread --- having invented various languages to serve the human purpose of exchanging 'information'. But a language, even quantitative mathematics, is only a mental construct; not something as physical as say, a brick, despite the way we physically represent it as 'squiggles on paper' or binary bits.

That's why I also .
[as Feeble Wonk # 42 said:]
"... struggle with the conceptualization of physical existence (as) consisting of only information."
Could this concept be just a bit of human foolishness?

I think its fair to be skeptical of ideas about what existence IS or CONSISTS of. But I wouldn't object to the idea that "physics is ABOUT information".
Physics is about measurement and interaction, which are exchanges of information. Time is about changing from one quantum state to another and this is a change of information. Entropy is unavailable or irrelevant information to the observer. The idea of "observer" is an information theoretical idea. Rovelli channeled Bohr when he said "we are not concerned with what Nature IS but with how she responds to measurement" or something like that. Theories do not say what Nature IS, they predict, again information.
So maybe we can throw this idea of nature "consisting" of information into the garbage.

OK Physics is ABOUT information---we all know that, and it is not a new idea, but that is not the same thing as "Nature consists".

Excuse me if I am talking vaguely and haven't studied the thread enough. Just saw a couple of posts that I liked, and wanted to say something.

 

[marcus]

... prefer to think of calculus as an evolved and heroic human invention; certainly not as a complex of discoveries.
... viva!

I think that is right. And the idea of numbers as mental constructs agrees verbatim with how numbers appear in the foundations of mathematics. Based on axiomatic set theory, the cardinal number 3 is the set of all sets with three elements. there is a one-to-one mapping between a set of three tigers to a set of three lions and so both those sets are elements of the cardinal number 3.
and the ordinal number 3 is {∅, {∅, {∅}}}
If S is an ordinal number you take the NEXT ordinal by forming the set consisting of the empty set ∅ and S, so the next ordinal is {∅, S}. You can see how I formed the ordinal number 3, by taking the number 2 and forming the next ordinal after that. One can also represent the ordinals as a sequence of tree graphs.

Clearly the numbers, in mathematics, are not "discovered" :w They did not jump from behind a bush and bite Pythagoras on the leg as he was ambling through the woods in Magna Graecia, as per Paulibus example.

However it is just possible that some aliens orbiting a nearby star, perhaps only 1000 lightyears from here, who were busy developing their civilization, could ALSO have thought up numbers. If they have thought of axiomatic set theory, all the better! It could be a bond between us, so that love or at least toleration, could grow up between intelligent (to use a flattering term) species.

 

[marcus]

..., which helps amazingly with living, prospering and surviving in this physically complex universe, so strangely equipped with past, present and future. But I think that mathematical patterns are 'only' intangible constructs of our minds, rather than tangible realities.

D'accord.

 

[Stephen Tashi]

I suggest that the participants in this thread return to technical issues and avoid the vague philosophical discussions because Philosophical threads on the forum get closed as a matter of policy.

I'd like to hear from anyone who can discuss the mathematical details of an information theoretic approach to a physical theory.

 

[marcus]

I suggest that the participants in this thread return to technical issues and avoid the vague philosophical discussions because Philosophical threads on the forum get closed as a matter of policy.

I'd like to hear from anyone who can discuss the mathematical details of an information theoretic approach to a physical theory.

Why sure, Stephen :) Let's take a look at these and see if we want to discuss them. I am especially interested in the frontier physics questions where there is no other explanation besides the information theoretical one.
For example in the context of GR there is no concept of thermal equilibrium! Because two systems can be in contact and nevertheless be at a different temperature. In GR, temperature is affected by position in gravitational potential. (Tolman effect). To arrive at a workable concept of thermal equilibrium you must actually introduce the concept of information flow between the systems. Temperature alone is not enough.

http://arxiv.org/abs/1309.0777
Coupling and thermal equilibrium in general-covariant systems
Goffredo Chirco, Hal M. Haggard, Carlo Rovelli
(Submitted on 3 Sep 2013)
A fully general-covariant formulation of statistical mechanics is still lacking. We take a step toward this theory by studying the meaning of statistical equilibrium for coupled, parametrized systems. We discuss how to couple parametrized systems. We express the thermalization hypothesis in a general-covariant context. This takes the form of vanishing of information flux. An interesting relation emerges between thermal equilibrium and gauge.
8 pages, 3 figures Physical Review D 88, 084027 (2013)

A paper for wide audience that is related to the Chirco Haggard Rovelli one mentioned above.
http://arxiv.org/abs/1311.0054
Relative information at the foundation of physics
Carlo Rovelli
(Submitted on 31 Oct 2013)
Shannon's notion of relative information between two physical systems can function as foundation for statistical mechanics and quantum mechanics, without referring to subjectivism or idealism. It can also represent a key missing element in the foundation of the naturalistic picture of the world, providing the conceptual tool for dealing with its apparent limitations. I comment on the relation between these ideas and Democritus.
3 pages. Second prize in the 2013 FQXi context "It From Bit or Bit From It?"

Another interesting question: why are gauge theories so prevalent in physics? A clue to this riddle is provided by considering how systems couple, so that information can flow between them. Gauge quantities can be mathematically redundant if the system is described in isolation, but essential (not redundant at all!) with the system coupled to the outside world. The very reason we have gauge theories could be information theoretical.
http://arxiv.org/abs/1308.5599
Why Gauge?
Carlo Rovelli
(Submitted on 26 Aug 2013)
The world appears to be well described by gauge theories; why? I suggest that gauge is more than mathematical redundancy. Gauge-dependent quantities can not be predicted, but there is a sense in which they can be measured. They describe "handles" though which systems couple: they represent real relational structures to which the experimentalist has access in measurement by supplying one of the relata in the measurement procedure itself. This observation leads to a physical interpretation for the ubiquity of gauge: it is a consequence of a relational structure of physical quantities.
8 pages published in Foundations of Physics 44 (2014) 91-104

 

[Paulibus]

However it is just possible that some aliens orbiting a nearby star, perhaps only 1000 light years from here, who were busy developing their civilization, could ALSO have thought up numbers.

I vaguely remember that NASA folk have already acted on this possibility. The human artefact that is now remotest from planet Earth is, I think, an early space probe (Pioneer?) that is now traveling away, far beyond the solar system. It carries a plaque with an engraved message to any alien folk 'out there' that may encounter it. This message consists of mathematical truths about geometry and/or numbers. The hope was that mathematics, as a universal language, could be understood by intelligent aliens who would then recognise that the plaque was evidence that another intelligent species existed.

I still hope that if this happened, the aliens would be benign folk who don't come looking for us as food!

Enough philosophic musings. Apologies.

 

[Stephen Tashi]

Let's take a look at these and see if we want to discuss them.
http://arxiv.org/abs/1311.0054

That philosophical paper would send us back to Philosophy.

It puts the burden of specifics on a reference to:
"Relational Quantum Mechanics" (1996) http://arxiv.org/pdf/quantph/9609002.pdf.

We could discuss that paper, although, just from scanning it, I'm not sure it establishes a formal structure for dealing with information in a quantitative way.

 

[marcus]

Stephen and Paulibus,
the one I would prefer is the one published in Physical Review D about inventing a concept of equilibrium that works in general covariant settings.
It quantifies information flow between two systems. And also relates that to the passage of time. Remember that TIME proceeds at different rates for things at different gravitational potential. So you see it is quite an intriguing problem. In ordinary statistical physics when two systems are placed in contact they implicitly experience the same time. One is not time-dilated relative to the other. But in the real world (GR) this is not true. If one is upstairs and one is down they have different time.
As well as (by the Tolman effect) different temperature even though they be closely coupled.

The only way to solve the contradictions is to introduce the idea of information. So I would vote for reading and discussing this one by Chirco Haggard Rovelli (CHR)

==excerpt from previous post==
For example in the context of GR there is no concept of thermal equilibrium! Because two systems can be in contact and nevertheless be at a different temperature. In GR, temperature is affected by position in gravitational potential. (Tolman effect). To arrive at a workable concept of thermal equilibrium you must actually introduce the concept of information flow between the systems. Temperature alone is not enough.

http://arxiv.org/abs/1309.0777
Coupling and thermal equilibrium in general-covariant systems
Goffredo Chirco, Hal M. Haggard, Carlo Rovelli
(Submitted on 3 Sep 2013)
A fully general-covariant formulation of statistical mechanics is still lacking. We take a step toward this theory by studying the meaning of statistical equilibrium for coupled, parametrized systems. We discuss how to couple parametrized systems. We express the thermalization hypothesis in a general-covariant context. This takes the form of vanishing of information flux. An interesting relation emerges between thermal equilibrium and gauge.
8 pages, 3 figures Physical Review D 88, 084027 (2013)

 

[Stephen Tashi]

http://arxiv.org/abs/1309.0777

Related to that paper we can add http://www.theorie.physik.uni-goettingen.de/forschung/qft/theses/dipl/Paetz.pdf to the Parade of Links. It might be an easier read.

I'm not particular about what papers are discussed. Discussing several at once will probably be no more or no less confusing to me that discussing one paper. I prefer to go through them step by step, starting to where the technicalities begin. I won't understand them if the discussion begins in the middle - but if there are forum members who can jump to the middle, don't let me hold you back.

 

[naima]

I am reading "Black Hole: a war of savants". In this very good book, Susskind writes that there is a limit in the quantity of bits that can be stored in a given region or on a given surface. Wheeler thinks in his "it from bit" point of view that space IS a set of elementary grains which contain 0/1 bits. Is LQG very far from this quest?

 

[Feeble Wonk]

I am not being argumentative just for the sake of the debate, but I believe this is a critical point in our discussion... perhaps THE critical point. I will concede that the "language" of mathematics is a human creation of abstract thought. Further, I will concede that through sheer human ingenuity we have progressively mastered the ability to manipulate the abstract mathematical concepts described by that language. As Paulibus has suggested, the "predictive" and "verifiable" nature of these abstract concepts has enabled us to use them as a mental tool, in combination with carefully designed and controlled experimentation, to learn about the world we live in.

Yes, yes and yes. And yet... In any physical system, "quantities" are an observable of sorts, either as a multitude or magnitude. The ancient brute holding 2 stones in each hand IS holding 4 stones, whether he can count them or not, let alone have the cognitive ability to perform the mental operation of addition. 2 such brutes, each holding 4 stones, WOULD have 8 stones in total, whether the abstract concept of multiplication had ever been conceived or not. Regardless of the language one uses to "represent" the quantities of 2,4 and 8, the quantities exist and, in that sense anyway, they are "real". The quantitative relationships exist in a spatial relation as well, and those relationships are similarly real, even in the absence of the abstract mathematical and/or geometric "representation" of the relationships.

Several millennia before the birth of Newton, if our ancient brute had thrown his stone up in the air, it would still have followed the classical parabolic trajectory described by Newton's calculus. Given, the calculus does not just describe an existing quantitative/geometric relationship, but a change in that relationship over time as a factor of gravity and momentum. Change implies action, which is just a fuzzy philosophical step away from causation. This is admittedly a slippery slope I think we should shy away from.
I would like to make it clear that I am not suggesting the quantity of stones ARE the stones themselves, or that the calculus describing the stone's trajectory IS the actual stone flying through the air. I am simply trying to establish that quantitative and spatial relationships exist in nature, as described by the increasingly abstract mathematical language created by humans, even in the absence of that language... indeed, even if humans had never evolved to begin with.
Furthermore, as we all know, the very human ingenuity that we've discussed, with the use of abstract mathematical concepts and carefully controlled experiment, has demonstrated with as much scientific certainty as can reasonably be expected that the stone, the brute that throws it, and even the beast that jumps from the bush to bite the leg of our clever primate, are all "course grained" human perceptions of physical processes that are quantitative ("quantumtative" if you will >_<) at a more fundamental level.

And lastly, as our Friend has reminded us, physical action at that fundamental level appears to be probabilistic by its very nature.

But the basis of matter is the quantum mechanical wave function, which seems to be a probabilistic creature by nature. So it seems the basis of reality is probabilistic. What is the wavefunction a distribution of, if not pure possibility from which we get information?

So, I am compelled to suggest that what we are questioning in this thread is not just "what physics is about", but what physical existence is about.

 

[Feeble Wonk]

Apologies about the philosophical tone of my last entry. I couldn't help myself. I'll drop the matter at this point.

 

[Stephen Tashi]

So, I am compelled to suggest that what we are questioning in this thread is not just "what physics is about", but what physical existence is about.

If we do that, I predict the thread will be closed since the nature of Existence is a metaphysical question.

If the thread is going to about "information as the key underlying physical principle", then someone should explain how information can be any sort of principle, key or otherwise. I mean someone should give a definition and some assumptions, not just post links and allude to the philsophical views of writers. For example, there is no definition of "information" in the paper by Hardy that I read.

 

[Feeble Wonk]

Agreed. Again, my apologies. That was initially my point when I asked if Atyy could expound on his statement that "information is physical". That sounded as if it might offer an avenue to an operating definition of the concept. It seems to me that I've read a similar argument by Charles Seife in one of his books (possibly Decoding the Universe), but I don't remember it clearly. I'll see if I can find it again.

 

[naima]

As it is difficult to define an information we could ask if there is a law for information conservation.
Even if information is ill defined we would have I_after - I_before = 0. (ambiguity could disappear while we subtract them.
There was a debate when Hawking said that information was lost if it felt in a black hole even if the Black hole evaporates.
I think that he believes that information is physical not only a thing in our minds.
Let us stop philosophy.

 

[Feeble Wonk]

...we could ask if there is a law for information conservation.

I have asked this question before on PF, with the thought that if a "law of information conservation" was formalized, then through Noether's theorem, we should be able to relate this to some type of fundamental symmetry. I couldn't get much feed back on that idea though.

 

[naima]

When a drop of ink fall in water we see where it is. later the water becomes grey and the location of ink is dissolved in the bottle. This is the usual growth of entropy. Entropy = hidden information.
When Susskind writes that information cannot be lost and when Hawking agrees but wrote "except in black holes" what are they talking about?
They are not talking about the shape of the statue of liberty.
Susskind says that when it falls in a BH , after it evaporated the information in the statue is back to our universe. It is clear that both are talking about something else.
Susskind writes that if you want to send one bit in a given BH one solution is to send it a photon whose wavelength is its Schwartzschild radius. With another BH you will need another wavelength but for all BH the surface of their horizon will increase of the same area.
A clear definition of "their information" is still lacking here.

 

[Feeble Wonk]

A clear definition of "their information" is still lacking here.

The way that I frequently see the term "information" used in physics is almost synonymous with "history"... the general idea that you can run the history back in time. In this sense, the information of previous times is always maintained. But I don't think this is consistent with the way the term is used in information theory, which seems to be more related to a system's entropy level, as you were suggesting Naima. I found Siefe's book last night, but haven't had time to read it yet. Unfortunately, it appears to be written more for the general public, so I doubt it will have a formalized definition for us. At first glance, he appears to lean heavily on Shannon's concept of information though.

 

[Ilja]

But the basis of matter is the quantum mechanical wave function, which seems to be a probabilistic creature by nature. So it seems the basis of reality is probabilistic. What is the wavefunction a distribution of, if not pure possibility from which we get information?

You think quantum theory is basic? I don't think so.
And the wave function is information about the configuration q(t). At least in realistic interpretations like dBB.

 

[Feeble Wonk]

You think quantum theory is basic? I don't think so.
And the wave function is information about the configuration q(t). At least in realistic interpretations like dBB.

"Realistic"?

 

[Ilja]

"Realistic"?

Of course. "Realistic" as used by Bell in the proof of his inequalities. dBB is even more, deterministic.

 

[Dale]

Closed pending moderation

 

[Nugatory]

Everyone, please read the rules for discussions in "Beyond the Standard Model": https://www.physicsforums.com/threads/forum-rules-please-read-before-posting.178075/.

This thread is closed.