Bit from It by Julian Barbour

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,

Tom

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.

I am confused how this essay is not rated higher than 7.3.

Albert,

You seem to deny that it is "the things themselves we observe but [only] the electromagnetic energy they emit." Why is the 'electromagnetic energy they emit' to be granted reality?

By your remarks it would seem that absolutely nothing is 'provable', and everything is meta-physical. I don't disagree with that, but it not only applies to Dr Barbour, but to everyone here.

I found your remarks on Dean Rickle's thread much more cogent.

Edwin Eugene Klingman

"I am the recipient of two large FQXi research grants, the current one for ``The nature of time and the structure of space''. "

What does the author of "The End of Time" have to say about the nature of time? A specific question: Why is space real and time is not?

For this contest from Dr. Barbour I am reading about different definitions of information. I wonder though: Intelligence needs information in order to reveal itself, so, what is information from the point of view of intelligence? In other words: What is interpreted by experience before theory begins?

James

Dear Sir,

Thank you for your sensible elucidation of 'information'--much needed. I fully agree that information must reflect real structure, and that 'bit' is a concept derived from experience with real things, not the other way around.

You are quite right that "A dot on a screen is not the unadorned answer to a straight question." Your example of the information preserved in rocks, about their geological history, is very much to the point. It amazes me that some thinkers see information "encoded" everywhere, without asking, encoded by whom and for what purpose? Yet, as you note, "Wheeler is explicit: bits are detector-elicited answers to yes or no quantum binary choices." This forcing of answers from nature as a binary decision response seems to be the latest evolution of an idea expounded by Aristotle (and which, ironically, he feared could produce only "monsters of nature", not true descriptions). It then progressed as Bacon's procuring nature's secrets under "torture". What next, one wonders?

I believe there are cultural reasons for the current information craze. I explore some of these in my own submission ("topic/852"), which I invite you to read. I also suspect that interest in the utility of 'information' as an ontological basis for 'reality' probably stems in part from its promise as a common bridge between the categories of 'mind' and 'matter'. In that context, its adaptation into physics from cognitive psychology can be no better than the understanding of physicists of the mind-body problem.

Best wishes,

Dan Bruiger

Information certainly has to do with 'its' but not with 'bits'. Why not, because bits are truncated, frozen, pieces of code. While a code can be considered information, for the sake of argument, it is only an incomplete symbol used to represent information.

James

Dr. Barbour,

You are welcome to use whatever description your deem to be appropriate to describe the value of what I ask or what I say. Perhaps silly is the correct description; however, I request that you say that is so. Otherwise, I assume that my points are irrefutable.

James

Dear Julian,

Congratulation for your clear essay on a fundamental Skakespearian question: bit from it or it from bit, (to bit or not to bit). I totally agree with your conclusion than "The set of all onta is the ultimate Shannon source." and argue that the answer is "It from bit from thing".

I would like to reconcile your point of view with Wheeler's and his followers. You write "It is a mistake to believe that the digits 0 and 1, being abstract, represent the immaterial". The main point is there: what does sounds that a bit is immaterial ? Is it totally abstract and not made of any 'thing' where a thing is not necessarily made of matter; or is it just not made of matter.

An immaterial bit can be both, not made of matter for Wheeler and made of thing for you. Here is how:

For me a bit is a topological feature of a very fundamental structure, a trivalent network in graph theory, or a set of cardinal 3 subsets in set theory (both are equivalent); This feature may be that if the node is in a 3-loop it holds value 1 otherwise value 0.

With this definition, I agree with you, bit is made of thing, the thing being one or three nodes, or cardinal 3 subsets; but remains immaterial, not made of any matter, nor having coordinates in any space background; because matter only get sense at a larger scale (a supernode of 48 bits). So, "They do not exist in isolation. A bit is not a single-digit atom of reality as it from bit implies."

But they exists together in a simple network that is a proto-space, encoding space, bosons and fermions.

Time is another story. Configurations (spin networks) are linked by pachner moves, forming spin foam, with a causality but no need of absolute clock. So my conclusion is: "It from bit from thing"; This "thing" is well documented in my essay.

Best regards

Ray

Dear Julian,

Your essay is very interesting. However, I have a remark. You use the Shannon theory of information in your essay. The Nyquist-Shannon sampling theorem gives a result on the frequencies showing when it is possible to discretize a continuous signal without losing information. This result is often used in engineering. Considering the Planck time, the Nyquist-Shannon sampling theorem implies that the frequency of a particle must be limited if we don't want to lose information. For instance, it implies that the energy of a photon must be limited.

Best regards,

Emmanuel

Dr. Barbour,

With all due respect for your qualifications: I think that your theoretical positions are near, actually beyond for me, to being unrealistic. Good luck to you in this contest and in the future.

James

Dear Julian

"The catch, all too often forgotten, is that an inertial frame of reference is needed to define the motion."

That sentence alone sums up the problem that remains central today. Do you think physics may recognise it one day?

Peter