With all due respect I wonder how people talk about the digital view and computation without even mentioning the seminal ideas of Turing, or the current developments of information theory beyond Shannon's theory developed in the 1930s. Only a couple of essays in the contest actually have some contributions considering the state of the art in the field.
Julian,
Thank you for addressing a topic that apparently needs addressing. I have nothing but respect for Wheeler, but 'It from Bit' went way over the edge.
I have argued on these threads that information is descriptive, not physically real, and been amazed that it could be thought otherwise. I attribute this partly to the "information-in-Black Hole-->area-of-Black hole", wherein 'information' is discussed as if it were particles. (Exactly the same area relation can be derived in terms of energy impinging on the Black Hole with no mention of information at all.)
It is probably the extreme confusion that accompanies the interpretation of 'non-locality' associated with the so-called 'violations' of Bell's (incorrectly calculated) inequality that has led to so much confusion about information. If I believed in non-locality and non-realism, it's hard for me to say what I would be willing to believe to be 'real'.
You state "Wheeler's thesis mistakes abstraction for reality." Korzybski's central message in 'Science and Sanity' is that "the map is not the territory." There would not appear to be anything simpler to understand, yet evidence is found everywhere that maps are confused with the territory. There must be something about the way our brains are structured that leads to such confusion. Clearly it may sometimes be useful in a Darwinian fashion for a brain to use the model "as if" it were the reality, but who would suspect that so many brilliant physicists would fail to discern the difference?
So thanks again for stating the obvious in a way that I hope most will follow.
Edwin Eugene Klingman
The essay is beautiful and I agree with the conclusion "Bit from It", in a way I will try to make clear. But I disagree with the way the conclusion was reached - it seems to me that the central part of Wheeler's 'ontology' "It from Bit" was overlooked, and this makes it look naive, while it is in fact very profound.
In a classical world, Wheeler's "It from Bit" would be obviously silly. When we measure something, we can write down the outcome as a string of digits, and by collecting all these digits we can determine the state. In such a world, "bit" would indeed originate from "it".
But Wheeler is discussing the quantum world. And for Wheeler, the quantum world is not just "classical world" plus "probability". Julian Barbour said: "Crucially, even if individual quantum outcomes are unpredictable, the probabilities for them are beautifully determined by a theory based on 'its'", but this is not the whole story. If this would be all, then he would indeed be right to say "I see nothing in Wheeler's arguments to suggest that we should reverse the mode of explanation that has so far served science so well". Julian Barbour tries to understand how Wheeler could do so trivial mistakes: "Wheeler's thesis mistakes abstraction for reality", and "A 'bit' has no meaning except in the context of the universe". Yet, there is no such a gross mistake.
Wheeler's "It from Bit" can be understood in the context of the "delayed choice experiment". He realizes that it is not enough to specify the outcome, but also what we measure - for example "which way" or "both ways" in the Mach-Zehnder experiment. But he realizes that our choice of what to measure determines how the state was (yes, in the past). This is the key problem of quantum mechanics, and this is the fundamental obstacle of all realistic interpretations of quantum mechanics: we choose "now" what to measure, and our present choice dictates how the state was, long time before we made our choice. We can think that there is an ontology behind the outcomes of our measurements, as in the classical world. But the "delayed choice experiment" shows that the "elements of reality" depend of the future choice of our measurements. And the outcomes depend of these choices too. So, it is in fact "the choice of what to measure" (Hermitian operator) plus "the outcome" (eigenvalue) that forms the "Bit" from Wheeler's "It from Bit". And the "It" is in fact the eigenstate corresponding to the obtained eigenvalue, given that the observable was that particular Hermitian operator. Wheeler was not that naive to think that eigenvalues determine eigenstates by themselves, without considering the Hermitian operator, so he accounted well for the prescription "A 'bit' has no meaning except in the context of the universe".
The central point of Wheeler's "It from Bit" is that the reality of today depends on the choices we make tomorrow, when we decide what to observe, and of the outcomes of the observations. He compares this with the game of 20 questions, when we try to guess a word by asking 20 yes/no questions, under the prescription that the choice of the word is not done at the beginning. The person who "knows" the word changes it by wish, so long as it remains consistent with the answer she already gave to our question. Wheeler wants to emphasize by this the similarity with the quantum state we try to determine, but which depends on what we choose to observe. This is why he was led to the idea that the state of the universe (it) results from the observations (bit).
I give more credit than Julian Barbour to the "It from Bit" philosophy - I view it as a way to present a central problem of quantum mechanics. I think, nevertheless, that it is exaggerated to conclude from this, as many do, that the world is digital. It may be or it may be not, but we should not force the conclusion. After all, the "It from Bit" philosophy is intended to clarify some points of a theory based on continuum - Quantum Mechanics.
My viewpoint on "It from Bit" is that we should regard the outcomes of measurements as "delayed initial conditions" for the Schrödinger's equation. I presented my view in this article and this video. A solution of a partial differential equation like Schrödinger's is determined by a set of initial conditions. Classically, the initial conditions can be determined from future observations. In Quantum Mechanics, the future observations determine the state in the two meanings of the word "determine": passive - "find out what it is" (by the selection of an eigenvalue of the observable), and active - "choose what it is" (by the choice of that observable). Another central problem is that two consecutive observations of the same quantum system are incompatible, if the observables do not commute. That is, they impose incompatible initial conditions to the wavefunction. But, the second measurement is not, in fact, a measurement of the same system. The system interacted with the first measurement device, and this measurement device has many degrees of freedom which are not determined yet. So, the second observation measures in fact the composed system - the observed system plus the apparatuses used for the previous observations, and all the past interactions of the observed system. This may offer enough degrees of freedom to maintain the unitary evolution and to avoid a discontinuous collapse of the wavefunction.
My interpretation comes with a realistic wavefunction, which is not yet determined among the possible wavefunctions, but whose "delayed initial conditions" are determined by all future and past observations. I think that we cannot avoid the idea of "delayed initial conditions", no matter what "It" we choose to consider as the underlying ontology.
My view is therefore that "It from Bit" and "Bit from It" are reciprocal: a set of possible "It"s (solutions to the Schrödinger's equation), a set of possible "Bit"s (observations, delayed initial conditions) and the Universe is a pair (It, Bit), so that the "It" and the "Bit"s are compatible.
On the other hand, the "Bit" itself is part of the solution of the Schrödinger's equation, that is, of the "It". This is why I said at the beginning that I agree with "Bit from It". But if we have some "delayed initial conditions" - the "Bit"s - the "It" that satisfies to them is not necessarily unique. So, in fact, what we have is not a pair (It, Bit), but a pair ("It"s that satisfy to the observed "Bit", the observed "Bit"). There is a relation "one-to-many" between the "Bit" and the "It"s. The "Bit" appears to be discrete, but the "It" may very well be continuous. So, although "It from Bit" reflects an important aspect of Quantum Mechanics, it should not be taken too far.
Dr. Barbour,
Hi. Your essay was very good. In regard to your thinking about a "thing" with "The way that they [the distinguishing attributes of a thing] are knit together defines the structure of the thing", I would strongly agree and made the same point in my essay ("Reality is digital, but its perception as digital or analog depends on the perspective of the observer"). There and elsewhere, I conclude that a "thing" exists if it is completely defined as to what is contained within, or meant by, that thing. This complete definition is an edge or boundary defining and delimiting what is contained within. This complete definition/edge/boundary gives substance and existence to a thing. I go on to show how this definition can be used in thinking about the question of "Why is there something rather than nothing?".
Again, very nice essay, and I would be interested in any feedback you might have. Thank you.
" There must be something about the way our brains are structured that leads to such confusion. Clearly it may sometimes be useful in a Darwinian fashion for a brain to use the model "as if" it were the reality, but who would suspect that so many brilliant physicists would fail to discern the difference?"
Edwin Eugene Klingman
Eugene,
Glad to see you here in the contest. This is not "brilliant" the physicists need. It is the visceral courage to address concepts that are in violent contradiction with all the assumptions required for our reality to be. It is scary and disturbing, but we must overcome this in order to move forward. My essay tells you about it, without any warning.
Good luck,
Marcel,
I'm not sure how it is possible (I have not read Roger's essay yet though) to define a "delimiting boundary" for a "thing" in the context of information, where "things" both create information, which we convert into various "bit" forms *and* are created by information from a more fundamental level. Can a "thing" be considered as complete in isolation from it's causes? For example a logic gate ("it") creates information by a given state, open/closed, which we interpret in bit form, yes/no, 1-0 etc. The gate itself is however constructed from more fundamental elements such as atoms which have supplied "information" that we have used to construct the physical gate. Atoms in turn are composed of elementary particles in a way determined by laws according to the "information" those laws carry. A regression by decreasing (more fundamental?) scale would seem to then leave us ultimately with just "laws of nature".
What status should we attribute to those laws? Are they primary in the sense that, as Dr Barbour says - "message sources could not exist if the universe were not subject to laws of nature". This would seem to attribute informational status to the laws. On the other hand, to quote Dr Barbour again - "I claim that the configuration carries intrinsic semantic information in the sense that different intelligent beings can in principle deduce the law or process that explains the observed structure". This implies "bit from it" whereas the former implies "it from bit"!
I guess it all depends on your definition of information, but I see physical laws as primary and "informational" in the above sense. Should the goal of science ideally be to find and describe necessary and sufficient causes for all "things" at ever more fundamental scales? This is in fact what the history, at least of physics, shows to be the case. Are there global natural laws , in the sense of (dare I say) a "multiverse" or "string landscape", which are primary even though there may be different mass spectra and gauge couplings locally and perhaps more fundamentally, compactified manifolds/brane geometries which are "informed" by these primary, global laws? Or perhaps a Bohm type primary "information field" giving form to what we see manifested as the "explicate" physical world? Again, "it from bit", but in a different sense to Wheeler's (I think absurd!) "self observing universe" meaning.
Cheers
Hi Marcel-Marie,
I can not agree. I know we are deceived by the limitations of out sensory capabilities and only imagine the experience to be objective reality itself. I do not accept that there is not a foundational level source of the input that is interpreted and also misinterpreted. Space-time is the appearance of reality that is observed but the sub atomic reality, that is unobserved, is in the most concrete sense of the word real. I have said this for a long time.
Mr Smith in his competition entry last year spoke of the timeless spatial configuration that Julian Barbour here names Onta. Which is a nice catchy term, relevant to what it -is- and is short and easy to say. The word is original (as far as I know) but the concept is not. There are a number of people, some have been conversing on FQXi blogs, who think this realism is necessary. Some have also entered the competition. Though perhaps it takes someone with Julian's reputaion and experience to say it for it to become an acceptable concept.
Without this kind of realism we are creating fantasies and making them real or believing that the magic of incomplete information is more real than solid objects that can not be observed. Quantum magic rabbits!
Roy states: "Atoms in turn are composed of elementary particles in a way determined by laws according to the "information" those laws carry. A regression by decreasing (more fundamental?) scale would seem to then leave us ultimately with just "laws of nature".
While this is probably the consensus, it begs the question of where the 'laws of nature' come from. Originally everyone knew that laws came from the 'king' and the laws of Nature came from the 'King', ie, God. But over the last century or two the King has been banished but his 'Laws' have been retained. In my model this is not kosher, and the laws must evolve from the 'self-interaction' of the basic substance of which the universe consists.
It does appear that we are capable, as conscious beings, of abstracting these behaviors in such a way that coded 'laws' can be derived that effectively generate an infinite amount of information, in the same way that the relation y=x^2 generates an infinite amount of information. I have developed the theory of such 'evolution of theories' in The Automatic Theory of Physics.
But do the 'laws' exist 'out there' governing what's happening 'in here' or are we simply part of a self-evolving, self-interacting 'substance' (for lack of a better word) that behaves according to Marcel's "law of non-contradiction". If the latter, then we have a unitary universe, complete in itself, and capable (despite Roy) of eventually 'observing itself'. Otherwise, we have a dualistic (schizophrenic?) universe where we have not only to figure out what 'reality' is, but where and how the 'laws' came to be. It's an easy choice for me.
The confusion of descriptive information, of meaning only to certain observers, with substantial reality that exists for all observers, leads to problems. In another thread it was suggested that "Watch out for the bus!" has consequences and so this information should be considered 'real'. But if you only speak Chinese, "Watch out for the bus" means nothing. Yet the energy of the moving bus is real in all cases. Information has reality only with respect to an observer. To deny the substantial reality one should stand in front of the bus and argue this point.
Edwin Eugene Klingman
Dr Barbour,
There are sections of your essay where you seem to be arguing against yourself. For example, you argue that QM "probablities are determined by the wave function/configuration space and the Schrodinger wave equation" and go on to say the probabilities are the "bits based on the its". Yet, by it's very nature, the standard interpretation of QM must deny real physical status for the wave function and therefore it's state space, as it is explicitly interpreted as representing only our knowledge of the system (information) and probabilities for *measurement outcomes* with *no reality in between observations*. It would seem that you are therefore attributing primacy to *information* contained in the state evolution.
You then equate the QM "laws and configurations" with classical mechanics, yet classical configurations have real physical status. By applying the analogy between QM and classical "laws" you would be arguing more along the lines of my previous post wherein primary laws are primary information content. This would seem to clash with - "Try eating a 1 that stands for an apple" in the sense that it would become - Try eating a law that describes the particles and interactions that compose what we call an apple!
Congratulations on the essay though. It is as usual, most thought provoking, just as "The End Of Time" was!
Good luck!
Roy,
Hi. Thanks for reading my posting. By "thing", I meant any existent state. This could be a typical "it" like a car or a logic gate, but it could also be concepts, information/bits, physical laws, etc. These are all existent states. A car exists outside the brain, but a mental image or concept of the car or information about the car can also exist inside the brain. There, it's composed of electrical gradients, neurons, etc., but it's still an existent state. To exist, all these things must be defined as to what is contained within, or meant by, those things. This definition is an edge or boundary giving substance or existence to the existent state.
In regard to physical laws, I pretty much agree with what Edwin wrote in that these laws also must be existent states. Many physicists and mathematicians say they exist in a Platonic realm somewhere that we can't see or examine. I can't argue with or refute that point. But, I could also say that a cheeseburger exists in that realm and that it is the source of all reality (sorry for the stupid joke). But, even if this Platonic realm does exist somewhere, it and the physical laws inside it are still existent states.
I think real progress in physics will come not when we decide what to call the most fundamental of all existent states (ie, call it a physical or mathematical law, information/bits, things, etc.) but when we can figure how and why that existent state can exist in the first place and what its properties are and use these to build a physical model of the universe. That's what I was trying to get at in my essay.
Thank you!
Roger
Dear Julian,
As my second favorite writer on time (you get three guesses as to the favorite--it's not I--and the first two don't count) -- you never disappoint. And when you speak geometry and information theory, it's with the same crisp authority and delightfully melodic prose that captivates from the beginning and carries to the end.
So it's not easy to suggest to a master of his subject that he's missed an opportunity. Fools rush in. Appendices are not part of the competition, so you're still a safe "10" -- still, I would point out in appendix B that your diagram for translations and rotations in Euclidean space, if my arithmetic is correct, is Euler characteristic 2. That of course implies a closed manifold of dimension 3 which corresponds to your N = 3 dimensionality. What's missing from this picture is what you're famous for; i.e., those rotations and translations are time dependent, and if there is nothing "left over," so to speak, through any transformation of points in 3-space, then time as least action has disappeared from your domain and quantum configuration space is static, as you hold. Nevertheless, the dynamics of mass points (Mach's principle) necessitates the inverse of Einstein's universe which is finite in time and unbounded in space -- i.e., to one which is finite in space and unbounded in time. Unbounded in time in this context gets you T = 1, and your static quantum universe holds.
A superior essay. Thank you.
Tom
Georgina,
All I wanted was to understand the universe by allowing it to exist and evolve by itself. i.e. without us in the way. "Understanding" logically the universe requires that we remove the observer.
The Copenhagen school knew about the underlying reality and said: There is nothing there worth our attention" They did quit in our name, so close .... They got scared and physics has been in a "refuge" mode since. Loitering around exotic ideas when they knowvery well were to look for answers...
Maybe, we are not looking for the same thing...? Me, I found what I was looking for.
Good luck,
Marcel,
Dear Julian,
I enjoyed your "Bit from It" essay. It was well-written, good examples were given, and I agree with your perspective (or clarification) of "Bit from It" being more fundamental than Wheeler's "It from Bit". I was a little disapponted (I still think that your paper deserves a perfect "10") that you addressed the continuous vs. discrete nature of reality in just a footnote (#7), but I was likewise guilty of addressing the concept of information in a mere footnote. I enjoyed your clarification of information vs. entropy - the two are similar enough that they often get mixed-up.
One example was how the explaination (from Aristotle to Ptolemy and ultimately to Kepler) of planetary motion on a 2-D background of space implied motion in a 3-D space. I think that clues exist in our apparantly (3+1)-D existance that imply more dimensions.
I also liked your example that "1" - by itself - is meaningless without units, thus emphasizing that the "It" is more fundamental than its "Bit" length of measure. Your example was that you can't eat "1" unless your "units" are something like "apple". Peter Van Gaalen's essay discusses various combinations of "units", and I think that each distinct type of unit may imply a distinct type of dimension.
You also mentioned that we can only observe half (at most) of the variables in a given experiment. My essay emphasizes that this is due to wave-particle duality and reciprocally-scaled dynamic variables (such as position and momentum). I also think that this implies that dimensions (and degrees-of-freedom - i.e. SUSY) need to be doubled.
Regarding Qubits, I recommend Larence Crowell's and Philip Gibbs' essays.
Have Fun!
Dr. Cosmic Ray
Yes I agree Marcel-Marie we do need to remove the observer but not entirely or the Universe vanishes entirely. No brain, no conception of an idea, no universe.
I do not seek answers in metaphysics or in magic. So we are looking in different realms. You have found what you were looking for and I have found what I was looking for in a kind of presentist realism. Newton considered his great work mere pebbles, found on the beach, near to the whole uncharted ocean. Shall we compare our little pebbles or just admit that we each prefer our own?I think the second choice is the most amicable solution.
Kind regards and Good luck to you too.
Dr Barbour,
You say: "What we observe and interpret as the outcome of an individual quantum event does not reside in space and time; it is embedded in a configuration."
If the configuration is in space and time and the 'outcome' is embedded in a configuration, then the 'outcome' should at least be in time if not in space.
The 'outcome' of an 'event' is 'embedded' in a 'configuration'. I supposed this simply means that "the abstract information is embedded in the corporeal formation". Is it?
You said nothing that clearly names and describes the fundamental component of the 'event' or 'configuration'. What is the fundamental component of the 'event' or 'particle' or 'configuration'? If for instance there is the quantum event or the quantum particle or the field configuration, then what is its fundamental component? Or if 'components', then what components? What is being vented, particulated or configured? And what components belong to the 'it' and what components belong to the 'bit'?
-
Regarding the "it from bit" or "bit from it", I think it has always been and ever will be that we have "it and bit" in unison and thus neither one derived from the other!
From my point of view, we have the kinematic configurations (the phenomena) - from the kinematic voids to the kinematic black holes and all the kinematic things in-between (e.g., the quantum particles, the familiar life-forms, etc.). The noumena are 'embedded' in all these phenomena -- all the realized events of the past as resolved in the present and all the possibilities of events of the yet to be resolved future.
In every kinematic configuration is the input-process-output (IPO) capability of intelligence or consciousness; and there are all degrees of intelligence or consciousness according to the IPO capabilities of the kinematic configurations.
The noumena and the phenomena are always realized in unison - concurrently. The current noumenal 'mental' state is always realized in unison or concurrent with the phenomenal 'brain' state.
I think phenomenal events generate phenomenal events; and the noumenals simply occur along with the phenomenals -- the bits along with the it, information along with the formation.
The mental conception of an idea may occur before the 'object' idea's incorporation; the conception precedes the incorporation, which suggests "it from bit" -- essentially the "thing in itself" before the "thing".
But, evidently, the current noumenal conception of the 'object' idea is that which is in the current phenomenal state of the brain -- the current incorporation of the current mental conception but not the remembered or predicted 'object' idea's incorporation itself. There is thus the "thing in itself" (the information) and the "thing" (the formation) in unison.
Therefore, it may be the "it and bit" -- and not the "it from bit" nor the "bit from it"!
Rafael
Dear Julian,
You write at the bottom of p.2 of your essay that "my position is that something that one does not directly observe exists if it explains phenomena."
However, there are often multiple distinct explanations for the same phenomenon (i.e., under-determination of theory by the facts). Thus, on this definition, existence is not unique, and the ontological basement of reality is a collection of different realities, each corresponding to a different way of saving the phenomena. Could you comment on this?
Regards,
Dear Julian,
The one problem I might have with what you say is that information in the Shannon sense does not include what appears to be a sematic depth you associate with it. The association of ontology seems to imply something with respect to realism which may not be quite operative. This is in particular since a quantum bit is just a particular way of formulating a quantum state. In effect there is an isomorphism between the quantum state and qubit. We then have nonlocality issues with quantum states, and Bell inequality violations which illustrate there is no underlying realism to quantum mechanics.
I have done work with quantum information with respect to black holes and it is in Discrete Time and Kleinian Structures in Duality Between Spacetime and Particle Physics. This covers some of the issues which the associated AdS sspacetime. There is a discrete quotient group, which as it turns out subsequent to submitting this has to do with a discrete structure on the Calabi-Yau form. This results in a "stringy derivation" of integer paritions.
The Bit from It or It from Bit I touch on in my essay, but where in effect I leave that up in the air. Quantum mechanics is really in effect devoid of reality outside of its measurement or reduction of states in some classical setting. The classical reality, though it is built up from quantum states, or may interfering quantum paths, or further from lots of quantum bits, is what we can say has "ontology," or is what we can tangibly identify as real. It also is what we might call "continuous, even if that breaks down when a small enough of a unit is looked at. This appears to connect with the ρ as evaluating the probability for some outcome, which you state in your paper.
I rather suspect the answer to this question is beyond our grasp, at least at this time. The process by which certain quantum states are stable under decoherence or quantum noise, and thus constitute a classical world, is marginally understood. Further, this einselection model requires invoking a prior estimate on such stability, which makes the einselection somehow observer dependent. The role of consciousness is utterly beyond our scope. It might require that to understand this in completion requires we have an understanding of how the universe through IGUS (information gathering and using systems) within the universe are able to completely characterize the universe itself. So the universe as a quantum computer, if we are to use that idea here, in effect generates a Turing machine which is capable of executing everything, including how that universal Turning machine is classical. This seems mathematically impossible.
Cheers LC
I much enjoyed reading your essay as to find it to be both a clarification and continuation of J.S. Bell's central complaint regarding the confusion inflicted when 'words' find themselves into theory as to be taken to have meaning exceeding what is reasonable.
"The concepts 'system', ' apparatus ', 'environment', immediately imply an artificial division of the world, and an intention to neglect, or take only schematic account of, the interaction across the split. The notions of 'microscopic' and 'macroscopic' defy precise definition. So also do the notions of 'reversible' and 'irreversible'. Einstein said that it is theory which decides what is 'observable'. I think he was right - 'observation' is a complicated and theory-laden business. Then that notion should not appear in the formulation of fundamental theory. Information? Whose information? Information about what? "
-J.S. Bell, "Against 'Measurement' ", Physics World (August, 1990)
Dr. Barbour,
I have read a book of yours in the past about Dynamics and Newton's Laws of Motion and I liked it. However, I do not agree that you proved that things, not information, are primary.
When we observe things, it is not the things themselves we observe but the electromagnetic energy they emit. Therefore, physically, we cannot verify this realism and it remains in the realms of metaphysics.