Thanks for the comments, Dean. And that's rather sneaky of you to pull out Eddington as a counter-argument! ;-) Seriously, though, you're absolutely right that you could interpret his "physical universe" definition in that manner. I guess I am simply showing my admitted bias towards an objective reality (and I suppose I am doing the same thing in my implication of a realm of "things in themselves").

On the other hand, it's useful to note that really the physics itself *didn't* change. Newton's laws are as true now as they were then. Engineers use them every day to build machines and buildings and all sorts of things. What Einstein found was that their realm of applicability was limited or, rather, they were a limiting case of a more general theory (and there's an argument that could be made that they can even be generalized anyway). What changed was our understanding of the variables involved (in this case, time).

Thanks for your comments Syed! I think you make a good point. It is possible to interpret what I say as formally anchoring science logic and mathematics, though I think it would be in a rather unusual way. It might be more correct to say that logic and mathematics are anchored to physics, rather than the other way around. Just a thought. Anyway, thanks again for the comments!

I think your question about a 3D box versus a 3D sphere is an interesting one. I don't have an immediate answer, though.

Hi Georgina, I think you make a very good point about what it means to "make a sound". And I agree that a subjective, uncorroborated view is not necessarily wrong. My point is simply that it is precisely that: subjective and uncorroborated.

Hi Steve, I am not sure what you mean when you keep leveling the charge of "vanity" at me. If it is because I have not responded to you yet, please excuse me. I'm just having a hard time following what you're saying and so I don't have anything to add to the conversation yet.

Sneaky indeed.

Just a quick follow up: you write "On the other hand, it's useful to note that really the physics itself *didn't* change. Newton's laws are as true now as they were then"

True, but, if we push the Eddington line, it's because we still know how to ask those questions and construct those experimental contexts (and agree on the invariants) as before.They are now stable, in terms of phenomena generated. Though that aspect has not changed, there were new phenomena (e.g. QM) that were generated as a result of new contexts/questions that could be posed, and on which objective agreement is reached. So the Physical Universe has expanded its list of characters and its plot.

I know you are not buying into something as extreme is this kind of Eddingtonianism, but it seemed that you wanted to say that the objective facts were in some sense co-created by the subjective elements along with the universe. In this sense, I think you might have to say there is change in the objective facts as the subjective elements change.

Cheers

Dean

Hi Professor Durham, I can understand your answer. I fight myself my defaults and we try to evolve and be humble in continuing to search our place inside this universe and why we are , I told all this because you work about this free will in fact, I have remarked that this Vanity is an important paramter to take into account considering the free will and I tell this for all persons , myself also, I have remarked that the education, the psychology, the encodings in our Environments create a free will about the beliefs and choices, what I tell is that this free will is under a pure psychological persuaded state for us. A sure thing is that this evolution and wisdom and this consciousness can permit a kind of humility and can change the opinions. That must be taken into account for me in the algorythms about this free will. An AI cannot really have this free will, it is probably just for these biological Creations. The determinism can converge with this consciousness evolving correlated with the universal deterministic truths, it is this that I tell, it exists things deterministic and other no and the choices can converge. The Humans generally are non deterministic , probably our global system creating this fact and our Young age at this universal scale. We are not robots but humans , there is a big difference. But we evolve. Like I said I have nothing against nobody, hope it is the same in the other sense, I am a nice guy, sometimes a Little bit crazy and arrogant but I work on me. I beleive returning about my Project to convice this UN that it is important, hope the thinkers and others shall be ok to follow a group of global collabotration without Vanity, because here we speak about the well of all and not about us, I just want to create a mannifest of solutions, Concrete and deterministic where the sciences and consciousness are the main chielfs of orchestra, I hjave remarked that this Vanity is a very big problem when you try to unite, it is odd, the persons have difficulties to follow, hope that their free will and choices can change, we must sometimes forget our own Lifes and work in team and complementarity for the common interest , general and global here, this planet must be optimised for me and the responsabilities of real universalists, skilling thinkers are essential.Alone I cannot convice and make all.

Hi Ian,

Thank you for a wonderfully written essay. I enjoyed it and I am largely in agreement with your conclusion, particularly when you wrote ``The fact remains that in order to say we comprehend some element of the universe we must necessarily obtain some information about that element. But obtaining that information is a physical process that necessarily has a context which constrains the nature of that information; the very act of acquiring information shapes the information acquired''.

This is an excellent point and the principle of comprehensibility is certainly a reflection of the physical limitations handed down by the uncertainty principle. As you point out, if the context of the questions being asked don't agree because we choose two incompatiable measurements---say x and p---then their is a fundamental limit to the comprehension we can achieve.

You then moved onto the price about the price of comprehension which fundamentally boils down to errors arising due to incompatible measurements. As you point out, if I'm computing pi to 50 trillion decimal places using two different algorithms, then surely they will reach different conclusions if they are not identical.

The uncertainty principle is certainly the fundamental limit of your essay, as it it in contextuality. If you ask an incomprehensible question, then it requires an infinite amount of energy to extract all the information about a particular variable. That is, localising your particles position does requires that you infinitely squeeze along p.

I largely agree with you and your essay and wrote a very similar essay focusing on the limits of computation, although focused from the perspective of open systems and dissipation---the errors arising from incomprehensible questions if you like---titled noisy machines. I hope you get a chance to take a look!

Well done on the great essay! I really enjoyed it!

Cheers,

Michael

    Dear Professor Ian Durham,

    Thanks for replying and sharing your thoughts!

    Well, the way I interpreted this is when posing questions and constraining the universe of answers, we make sure it corresponds well to certain underlying grammar and semantics; and thus physics gets anchored to logic and mathematics.

    In other words, science is projection of our observation onto the canvas of formal systems, such as logic and mathematics; hence why I stated physics gets anchored to mathematics and logic rather than the other way around.

    In many way your work resonates well with Wittgenstein's seminal work Tractatus Logico-Philosophicus where he emphasis the centrality of language in understanding the world.

    Best Wishes,

    Raiyan Reza

    Dear Ian,

    This is a well-written essay for a general science readership that explains and defends thought provoking ideas. In other words, a perfect fqxi contest essay. It was fun to read and I think you had fun writing it. I hope you do well.

    You do blame the state of the Physics on observers in the Universe, but your statements would offend only people in that category. On the serious side, the mechanics of creating valuable questions is the most important skill needed in science.

    Sincerely,

    Jeff Schmitz

      Hmm. I'll have to think about that. It's a very interesting observation. Thanks for offering some stimulating ideas!

      Fair enough. I can see how that comes across. Maybe my thinking has evolved on the subject. I absolutely firmly believe in objective reality, but maybe my work on consciousness has gotten me to realize just how constrained our view of the world is.

      Thank you for your wonderful comments, Michael! I think that the uncertainty principle may be related to what I say, but I'm not entirely certain if it is the logical limit of my argument. Technically the uncertainty principle is related to non-commuting observables so there would have to be some way to represent comprehensibility in this manner. It might be possible, but I'm not sure. But, yes, I do believe the two ideas are related.

      Hi Jeff, thank you so much for your kind comments! I am so glad it was an accessible essay. I think the art of creating valuable questions and its importance to science, is vastly underappreciated. I tell my students that knowing which questions to ask is often more important than obtaining the answers.

      Hi Ian,

      My essay "Why your Robot is just not that into you" is mathematically out of the running, but I would like your opinion (bad or good). Any comments would be helpful for the next contest.

      Sincerely,

      Jeff

      Dear Ian,

      "Why is the Universe so comprehensible?" A great topic to which you have written a most stimulating essay.

      I think our world is comprehensible because humans are good at searching out and then explaining patterns. First in natural science, then in our own creation - mathematics. As our science progressed, some of the patterns, or our deductions about them became established as our principles or laws - especially where symmetry was involved.

      I believe, like Einstein, that `comprehensibility' means a scientific understanding of the universe's functional composition. In my essay I cover how the 3 Un's have impinged on my thinking as I work towards my goal of 'Structural Physics'.

      If a condition of comprehensibility is one of measurement, and as you quoted "Feynman once famously said, if something disagrees with experiment then it's wrong", then isn't defining the experiment and its measurement in a truth-conditional way extremely important. Some might argue that is where EPR experiments have come unstuck. Part of the price of comprehensibility is the way we design our experiments.

      On another thought-line, you stated: "Markus Muller recently constructed a self-consistent theory in which an objective external world emerges from more fundamental observer states." Isn't this similar in some way to applying Susskind and 't Hooft's idea of a holographic black hole event horizon to the Universe through multiple observer states? After all, Muller thinks the link between entropy and information remains, possibly leading to a holographic principle.

      Thanks for your essay as it has extended the boundaries of my thinking.

      Lockie Cresswell

        Dear Ian,

        I am absolutely delighted by this essay. One of the things you touch on is the separability (for lack of a better word) of the universe. We can make sense of it because of how explanations remain "in their proper bounds".

        One thing I'm curious about: are there examples in "normal" life where explanations go out of bounds? i.e., you write "While it is impossible to prove that the answer to the question "what color is my hair?" will never be "narrow" or "dog", the fact remains that it is highly unlikely." It is possible to come up with an example that (however unlikely) violates the Principle of Comprehensibility?

        Yours,

        Simon

        (You can find some remarks on "mutual explainability" in my contribution this year, for which I'd love to have your thoughts--please feel free to drop me a line by e-mail or as you please, because I think there's a lot of philosophical literature for me to learn from.) https://fqxi.org/community/forum/topic/3492

          Dear Professor Ian Durham,

          Thanks!

          And, I am glad you found my remarks worthwhile.

          Best,

          Raiyan Reza

          Hi Ian,

          I waited a while to read your essay as I thought, comprehensibility is a too incomprehensible expression in order to get something comprehensible out of it. I was wrong. It was a clear enjoyable read. A few questions however remained that I would like to ask and a few remarks I would like to make.

          It seems to me, that you the context, under which a question can be comprehensive, must be classical. I completely agree, that the very meaning of a spin, implies the possibility to make an experiment along some direction and that we can know in which direction has been made (and share this information). This means that the directions must be somehow classically distinguishable. They can be constructed as coherent spin states. But could you imagine, that someone holds a superposition of two such 'classical' states as context and not being able to agree with you in which direction the spin measurement has been done? Or do you see limits in the applicability of the superposition principle?

          I personally cannot really get some operation meaning from such a superposition, as normally the superposition is not an eigenstate of a generator of the group SU(2) representation except for the lowest non trivial representation 1/2. But then one of the main principles of the QM seem to have only limited applicability.

          In a similar matter you seem to look for a reconciliation between the subjective view and an objective one. This seem to me is a problem brought to us mainly in QM and specifically by Wigner's friend type experiments. Does the stability of the universe also here play a role for the comprehensibility of the experiment?

          The stability of the universe sounds for me extremely dramatic and I do not know what you exactly count as stable. I asked this last question, because in my essay, the condition for an experiment to be comprehensible (I call it definable or measurable in my essay), is to be unitary and symmetric. So if Wigner tries to measure his friend being in the superposition with the probe, he breaks unitarity and symmetry within the friends subsystem. So Wigner trying to make a incompatible measurement on his friend would be enough to destroy the stability of his friends lab experiment.

          You actually do not answer the question of why the universe is comprehensible, but of under which conditions it is. I would be happy, if you would find the time to read and comment on my essay that has a similar topic. I ask under which physical condition physical concepts are definable.

          Luca

            Dear Ian,

            Good essay, interesting view. I agree there "..exist problems that are undecidable for physical reasons" and "The universe has fundamental limits baked into it." but can we not reduce them to 'infinitessimals'? If you interact with a spinning sphere at the equator and I ask; 'Is it + or - rotation?' Can you tell me? But how CLOSE to the equator must we be get 50:50 certainty? Is that not, as I think you suggest, just a matter of experimental precision, so can be reduced!? Now that +/- decidability also INCREASES, by CosTheta Latitude, from 0 to 1 towards the poles.

            So now consider your Stern-G Fig.1.; We know all light has ellipticity, as do all orbitals, so if we hypothesise polariser interactions can change ellipticity (major axis orientation) as well as polarity, then we can say the magnets divert the 'state' BOTH WAYS, but only ONE channel corresponds to major axis amplitude so can 'click'.

            Now in THAT case, with some simple conditions (shared axis, and vector additions) we can surely reduce 'quantum uncertainty' to the physical limit you suggest!? I've found that a powerfully resolving hypothesis, as I discuss in my own essay, giving Bells inequalities physically, as he always suggested was possible.

            We can then ask the truth value question; "is my hair blond?" and get answers of recursively reducing precision of HOW blonde!? So a 'reducing' not 'excluded' middle between Blonde and Brunette.

            You struggled with that concept last year, perhaps even ran from it as some do. Now I think it should be more comprehensible from your own viewpoint. Do let me know.

            Very best

            Peter