Emily

Great Job. It's almost as if you're giving a conceptual analysis of my essay! I can't then help but to agree just about all. And so well analysed and expressed. But I would like you to examine my concrete proposals for what you suggest.

But let deal with the one discordant thing; your apparent agreement that we now "definitely can't have locality" AT ALL!

Could you answer these questions about a row of 20 spinning balls with random orientations of axis. Wear a blindfold and try an 'exchange of momentum' with your finger tip, (representing polariser electron 'absorption'), then answering each time;

1. Is the surface moving UP? or DOWN?

2. Is it rotating clockwise? (PLUS) or anti clockwise? (MINUS).

Fundamentally easy Yes? ..Or is it!?

You encounter one with perfectly vertical motion, easy. BUT how certain is you +/- answer?

You then touch one on a pole. +/- is easy Yes. So how certain are you then about UP/DOWN?!

That is the natural physical PROPENSITY, and the more you test the more divergence from certainty.

I gave the full Stern-Gerlach A/B 'measurement' sequence for that last year, giving Cos2Theta & Diracs QM equation, verified by Trails essays computer plot, but few even understand the problem, & most that do run a mile in the blindfold! (as Jochen Sz). I suspect you may see be less scared of it's consequences Emma?

I touch on it again this year, but mostly on the consequences of updating our most fundamental ageing 'Laws'. I look forward to discussing.

Very well done for yours. I have to down for a well earned top score.

Very best

Peter

    9 days later

    Dear Emily Christine Adlam,

    A very interesting essay. John Schultz's essay suggests that the limitations on knowability posed by algorithmic patterns are not applicable to non-algorithmic patterns. As a consequence, this escape from algorithmic limitations on knowability would have the side effect of limiting predictions, seemingly in agreement with your essay. A further consequence is that knowledge of ontology might become feasible, as opposed to the position of one commenter who claimed it is hubris to claim to know ontology. Feynman: "more can be known than can be proven."

    My updated essay proposes a means of understanding that is not based on predictions and I think you might find it interesting and worth thinking about.

    Deciding on the nature of time and space

    Best regards,

    Edwin Eugene Klingman

      6 days later

      Hi Emily,

      Thanks again for another really well written essay! You make an excellent point when you write that if we take the 'pre' literally in prediction, then we appear to be bound to two perspectives; either a fundamentally probabilistic theory, or hidden variables. Given we know local hidden variables seem to be bogus from Bell's theorem and further results experiments, it's pretty clear we need a global theory as you beautifully articulated.

      You mentioned several proposed undecidable physical systems i.e gapped vs ungapped energy bands. It would seem to me that these experiments would necessarily need to be built as local subsystems of the universe in a lab. By construction, they would be immersed in a thermal environment. Unless your experiment is perfectly decoupled from the world, it would necessarily be subject to the laws of thermodynamics which may induce a symmetry breaking in the system and force a solution and making it unpredictable simply because you're ignorant of the state of environment.

      Thermodynamics and statistical mechanics are certainly emergent theories, but do you think this is only the case because if how we constructed modern science? I guess my question would then be, do you think thermodynamics in itself is a consequence of 'pre' way of thinking about nature?

      Again, thanks for the great essay! If you get chance, I'd love to get your take on mine if you get a chance :)

      Cheers,

      Michael

        12 days later

        Dear Emily,

        I enjoyed reading your essay! I find it well-argued and well-written, and you point to several important insights and questions. For example, I really liked your point about "objective chance": it's much more than just having "arbitrary" outcomes, and one may wonder about the structural peculiarities of such a claim. In particular, how come we can navigate the world successfully by betting on those probabilities *in the long run* if the events are assumed to somehow happen *locally*? Given this, then global constraints of the kind you imagine seem like a plausible idea to pursue.

        However, let me ask you about a question that you formulate: "How are the laws of nature enforced?" Are you really sure that in a "universe [...] made up of tiny objects undergoing various sorts of local interactions, it's natural not to worry too much about how the laws of nature get enforced"?

        Even in this case, one could imagine asking: what is *actually, in all detail* happening when two particles (or billiard balls) collide? Why don't they just move across each other? Or, perhaps with a more religious ancient mindset: what kind of god is actually enforcing the collision laws, by making the balls turn when they come close?

        It seems to me that the "how-enforced"-question can indifferently be asked in all settings whatsoever. And that many physicists refrain from asking it not because it would be a hard question, but because they see it as an all-too-human non-question (like: which god enforces the collision laws?) which we have learned to give up.

        How would you argue against such a view? I'd be curious about your opinion.

        Best,

        Markus

          Thank you very much for reading the essay, and for your comments!

          I actually agree entirely with what you say - I think the 'how-enforced' questions is just as difficult for the billiard ball case as for the global constraint case. However, the point I was trying to make is that for many people, the 'how-enforced' problem looks worse in the global case, because we can't resort to the intuitive picture of small particles colliding that we have all internalised. Thus global theories are often viewed as less plausible than local theories, even though the problems of principle are really the same in each case.

          I also have a lot of sympathy with the idea that the 'how-enforced' question isn't actually well-formed and that physicists should learn not to ask it. My concern, however, is that even if physicists don't raise such questions explicitly, nonetheless we may still have ideas of this type in the back of our minds when we evaluate the relative plausibility of various theories, and this can potentially lead to unjustified prejudice against certain types of theories (such as global ones).

          Thank you for reading, and for your comments!

          I'm glad you raise the subject of thermodynamics, because I think it's a really interesting example of a theory which mixes physical laws with perspectival elements. The Boltzmann entropy, for example, is in some sense a summary of how much information we have (or rather, lack) about the microstate of a system, and so the second law of thermodynamics can in some sense be thought of as a reflection of the fact that if we prepare a system in a known state and then let it evolve, we will inevitably lose information about it. (I am grossly oversimplifying of course!). So the fact that it takes the form it does is certainly a consequence of our interest in taking initial states and projecting them forward in time.

          Thank you very much for reading and for your comments! I'm excited to hear that you're working on ideas similar to this and I'm looking forward to reading your essay.

          Thank you very much for reading! I definitely agree with your comments on the importance of conceptual understanding - as you say, we never fully came to grips with the conceptual elements of quantum theory, and this has affected all the physics that has been done since. So studying the interpretation of quantum mechanics isn't just a matter of intellectual curiosity, it's a promising route toward making new progress in physics.

          I look forward to reading about your new approach to the interpretation problem!

          Thank you for reading, and for your comments!

          I'm very interested in what you have to say about locality. I should clarify that I don't necessarily believe physics definitely can't be local - what I intended to convey in the essay was that if we accept Bell's theorem then we can't have locality (regardless of whether we have determinism) - but of course there are various ways of getting around Bell's theorem, such as the Everett interpretation or superdeterminism. For various reasons I'm a bit sceptical about both of those, but I'm always interested in new takes on this issue and I look forward to reading your essay!

          Thank you for your comments!

          At present I don't know of any examples of retrocausal theories actually yielding new predictions. However, there seems to be quite a lot of evidence that quantum mechanics may actually be retrocausal in character (e.g. see the recent paper by Leifer and Pusey). And if the laws of nature are in fact retrocausal in character, then it seems to me likely that the best way to make progress is to allow ourselves to write down laws which are retrocausal and try to understand what their consequences would be for the world as we observe it.

          Thank you for reading! I'm interested to see how limitations on knowability affect predictability, and I'm intrigued by the suggestion that there could be some way to have definite knowledge of ontology, so I look forward to reading your essay!

          Dear Emily,

          I greatly appreciated your work and discussion. I am very glad that you are not thinking in abstract patterns.

          "Insisting that all theories should takea predictive form from the start places an unnecessary and unjustified constraint on thespace of possible theories, and by removing that constraint we will probably be able todo better physics, no matter what the purpose of physics might turn out to be".

          While the discussion lasted, I wrote an article: "Practical guidance on calculating resonant frequencies at four levels of diagnosis and inactivation of COVID-19 coronavirus", due to the high relevance of this topic. The work is based on the practical solution of problems in quantum mechanics, presented in the essay FQXi 2019-2020 "Universal quantum laws of the universe to solve the problems of unsolvability, computability and unpredictability".

          I hope that my modest results of work will provide you with information for thought.

          Warm Regards, `

          Vladimir

          Dear Emily,

          As you note, the very concept of probability is tricky and unclear. Yet we "find" it and have to work with it anyway. I find the issue of correlated quantum measurements even more baffling than just the measurements by themselves.

          7 days later

          Ah, I see! Yes, I entirely agree with this! It *looks* worse in the global case, but it isn't really.

          Good luck for the contest!

          Best, Markus

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