Olaf - nice essay highlighting the issue with information. I believe we met briefly at the Perimeter Institute a few years ago.

I'm not sure I like this essay as much as your previous work, but thank you for introducing me to the concept of generalized rigidity, which I was previously not aware of.

I wonder, how does that tie in with, say, an entangled system? Does entanglement create a physical rigidity in condensed matter?

As you will see, I have an interest in this topic as I explore the notion of entanglement in an argument that will at first seem quite absurd:

http://fqxi.org/community/forum/topic/1897

Good luck with the contest.

Kind regards, Paul

    Dear Olaf

    I'd like to report something that I have already said in my thread, answering to your post, about your nicely written and interesting essay. To be honest I should confess that I share essentially nothing of your essay, though I rated it high since it is pleasant to read, provocative, and complementary to mine as Giovanni Amelino-Camelia says.

    What I do not share is the "linguistic" notion of information, i.e. with a "meaning". This may make sense for classical information, which is sharable. But what is the meaning of quantum information, which is not sharable, but is secret? If you don't thing that quantum information is technically a kind of information (and for you information is only classical), I strongly suggest you the Pavia axiomatics for QT (PRA A 84 012311 (2011) http://pra.aps.org/abstract/PRA/v84/i1/e012311). The difference between classical and quantum information, is that the quantum one is purifiable, namely is only apparently lost, it is always preserved as long as you have control of the environment.

    I can accept your assertion that "meaning arises through interaction, it is dynamic, and it is internal". But you should be more specific about it. How do you qualify the meaning in terms of the interaction? You cannot deny that interaction is ultimately only quantum. What is the quantum meaning in terms of the unitary operator? Internal to what? You should be more specific. How I describe mathematically the meaning? In your post you say: "Think of the list of positions of the atoms and molecules that make up the river (or ship). What does this list of numbers mean? To give meaning to these numbers you have to give a procedure of how to position the atoms. This requires material objects (like the standard meter that used to be in Paris)." My answer is: There is no such a way of measuring position of atoms. There are only outcomes from an indirect inference of the atom position within a theoretical description. The only position measurement in your sense is the classical measurement: then the meter is emergent notion at the topmost level.

    You say: "Without matter information is literally meaningless". Here we are really at the opposite sides. For me matter is emergent! You are talking of the usual linguistic information, with a semantic, the one that we are using here in the blog, Not the one made of bits or the qubits. What are the meanings of the bit values 0 and 1? Information is processed by a computer in a "meaningless" way as a binary code. It seems to me that you missed the meaning of the theme of the essay competition: "It from Bit or Bit from It?" Not information in usual semantic sense.

    However, apart from our manifest disagreement, I liked your essay, and I rated it well.

    Best wishes,

    with friendship

    Mauro

    Dear All

    A standard-issue big city all-glass high-rise stands across the street from my usual bus stop. When I look up the high-rise facade, I can see the reflections of the near-by buildings and the white clouds from the sky above. Even when everything else looks pretty much the same, the reflections of the clouds are different, hour to hour and day to day.

    After I boarded the bus, I rushed to get a single seat facing four others on a slightly elevated platorm. From my vantage point, I can't help noticing the shoes of the four passengers across from my seat are not the same, by either the make , the design, or the style, and that is true even when the four passengers happen to be members of the same family.

    I could change the objects of my fascination from shoes to something else, to buttons on the dresses for example, but I do not think the result would have been any different. Diversity or Uniqueness would still rule the day! (There is a delightful essay on the subject of uniqueness by Joe Fisher in this contest.)

    I am pretty sure people are fascinated by the diversity and the uniqueness in the world, when the other side of it is the inevitable boredom of sameness every time.

    However, we have a need to know where all this beautiful and enchanting diversity comes from. Borrowing Wheelerian phraseology of "How come the quantum?", I ask "How come the diversity?" A standard physics answer is "Entropy always increases." (I am not a physicist, and I don't know if that is the final answer.)

    Whenever I'm out of my depth, I go back to my theory of everything (TOE), which is a mental brew of common sense, intuition, gut, analogy, judgement, etc. etc. , buttressed when I can with a little thought-experiment.

    The thought-experiment is simple. Imagine cutting a circle into two precisely, identical, and equal parts. Practically, there is no way we can get the desired result, because one part will be bigger or smaller in some way.

    Physics - especially quantum physics - says it don't matter, do the superposition!

    But superposition is fictive, an invention like the Macarena dance, and it has given us a cat, alive and dead at the same time.

    I have heard that angels can dance on the tip of the needle, and now I'm finding out some of us can too!

    Cheers and Good Luck to All,

    Than Tin

      Dear Than:

      Thanks for the wishes.

      All the best.

      Olaf

      P.S.: Have you looked at http://xkcd.com/1240/.

      Dear Paul:

      Thank you for your interest in my essay!

      Regarding the question of entanglement and rigidity it seems that there is no direct connection because standard examples of rigidity are not entangled (think of the product state of all spins up). This is an ongoing and hot research topic right now: How important is entanglement for the low energy properties of large quantum systems? (Papers by Verstraate should have answers)

      I'll have a look at your essay!

      All the best.

      Olaf

      Dear Torsten:

      Thank you for looking at my essay!

      An application sounds very interesting. I'll definitely have a look.

      Cheers

      Olaf

      Dear Hugh:

      Thanks so much for your thoughtful reply to my essay!

      I have actually thought about the similarities between the layers in my essay and the layers that appear when programming. I think though that there is a clear difference. Think of a subroutine in a computer program:

      procedure DoStuff( var1, var2, ... )

      begin

      ...

      return stuff;

      You can use this procedure from a higher level and you do not care how it looks on the inside. You can replace the whole thing and as long as the new routine accepts the same variables and returns the same kind of data you'll be fine.

      The important point is now that you have to know what kind of data to hand the procedure and what to expect back (c++ overloading is just a slight weakening of this). This part of the procedure is external to it. What I was describing is more internal. The meaning of a procedure becomes clear by kicking it.

      I think our real difference becomes clear when you say: "Yes, but a dictionary is just information, more bits. It does not have to contain (even pointers to) Its." You are pointing to an infinite regression here that I want to end. The way I do this is by having Its interact. That is the key part of my argument.

      Looking forward to reading your essay.

      Cheers

      Olaf

      Dear Charles:

      Thanks so much for reading my essay and the kind comment!

      I think the connection of emergence and randomness is important. In particular in connection with the measurement problem.

      Cheers

      Olaf

      Dear Jim:

      Thanks for reading my essay and commenting on it so kindly.

      Looking forward to your essay.

      Cheers

      Olaf

      Dear Amazigh:

      Thank you very much for the good wishes (and rating the essay)!

      I'll have a look at your essay.

      Cheers

      Olaf

      Dear Carlo:

      Thanks for the interest in the essay and acknowledging the point. It was important for me to capture enough of the a notion of information (and the shortcomings of the old notion) that it becomes apparent how it is related to the solution of a number of problems (like the measurement problem).

      A tighter definition will appear in a longer article.

      Cheers

      Olaf

      P.S.: I think emergence is a really important concept that has not been properly understood yet. I think it is also important in quantum gravity and allows for results like these (alternative to inflation):

      http://arxiv.org/abs/1307.6169

      Dear Vladimir:

      I think your quote is spot on! Thanks for the kind comments.

      I'll have a look at your essay (so many essays to read!).

      Cheers

      Olaf

      Dear John:

      Thanks for the interest in my essay. I am going to have a look at your essay and see if I can answer your question.

      Cheers

      Olaf

      Dear Yuri:

      I liked the quote from Wheeler. I am not sure I get the claim. It would really help if you could state the claim more clearly. What are the places where the angle of 18 appears? Are there exceptions? What works? What does not?

      The point with these kind of things is that they might signify something deep or they might just lead you astray. People have invested a lot of time on the fact that the fine structure constant is 1/137. Why 137? As far as I can tell no good reason has been given yet.

      It would really help if you'd work on the presentation.

      Cheers

      Olaf

      Dear Amos:

      Sorry if I wasn't clear. About the asymmetry:

      When the system reaches a ground state it has fewer symmetries than before. Think of a system of spins. Before the transition they point in all possible directions after the transition all spins point in one direction. Which direction is determined by random fluctuations. That is the connection between randomness and asymmetry.

      Thanks for the interest.

      Cheers

      Olaf

      Dear Olaf

      Thank you for constructional criticism of my essay. It benefits rather than complimenting from nonprofessionals.

      I will try to answer your questions.

      1.My observation 18 deg concerning only pseudoscalar mesons where spin=0 and two charged leptons(mu and tau) where spin=1/2.But 18 deg no so important than symmetry around proton.This is an amazing symmetry was not noticed until now.

      2.Puzzle of 137 is more sophisticate than 1836,because contains 3 components (c,e,h) whereas 1836 contains only one(m) component

      Cheers

      Yuri

      Dear Yutaka:

      Thank you for the interest in my essay. I have just read your essay and I very much like the operational point of view. I think I am not clear what you mean when you say

      Operational thinking has been formalized as information theory.

      Can you explain what you mean here?

      Cheers

      Olaf

      Dear Yuri:

      I guess the number of different contributions to this essay contest attest to the difficulty of coming up with a good description of what we mean by information. I am not sure that this the greatest riddle though.

      Cheers

      Olaf

      Dear Joe:

      Thanks so much for the kind words. Can you explain a bit more what you mean when you use the word once? I am not sure I understand.

      Cheers

      Olaf

      Dear Giovanni:

      Thanks for these remarks! I guess I have to read Lee's book now.

      The discussion with Mauro has just started (further down).

      Cheers

      Olaf