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FQXi FORUM
September 19, 2021

CATEGORY: Undecidability, Uncomputability, and Unpredictability Essay Contest (2019-2020) [back]
TOPIC: Putting the 'Pre' in 'Unpredictability' by Emily Christine Adlam [refresh]
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Author Emily Christine Adlam wrote on Mar. 16, 2020 @ 16:44 GMT
Essay Abstract

Making predictions is a fundamental part of doing physics. Or is it?

Author Bio

Emily Adlam studied Physics and Philosophy at Oxford University and then did a PhD in quantum information and foundations at Cambridge University.

Download Essay PDF File

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Yehonatan Knoll wrote on Mar. 16, 2020 @ 20:40 GMT
A well written essay!

You may be interested in my concrete proposal for such a non mechanistic universe (ECD). It shows that we have been looking wrongly not only at QM (as you anticipate), but also at almost everything else.

A crucial feature of ECD, being an `all at once' ontology, which you have ignored in your essay, is quasi-locality. PDE's, being local, guarantee that apples are localized solutions irrespective of almost anything. You want to, at most, replace the constraint imposed by a PDE on the variables in an infinitesimal neighborhood of a spacetime point, by a constraint in a finite (but small enough) neighborhood.

With quasi locality, the universe becomes fundamentally non mechanistic (non IVP in my terminology) as opposed to the superficially non mechanistic Lagrangian formulation of classical mechanics. I think that the notion of `retrocausality' can them be more easily sold to the general physics community, as it is no longer a statement about machines, which just propagate in time their initial conditions, oblivious to any interaction in their future.

Yehonatan Knoll

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Yehonatan Knoll replied on Mar. 17, 2020 @ 12:32 GMT
Let me be more accurate with regard to quasi locality: In discretized form, a PDE relates finitely many dynamical variables in the neighborhood of a spacetime point, all (almost) equally weighted. The ECD generalization involves infinitely many such variables, but those are highly non uniformly weighted, with weights rapidly decreasing with covariant distance to that point. This allows only for an approximate, rather than deterministic, time propagation of a system based only on its past and present states. The degree to which such an approximated local propagation departs from the exact solution is determined by its measure of `chaosity'.

Note, nonetheless, that even if you somehow got access to the future state of a system (you `remembered' its future as well) which would allow you propagate it exactly, that information about the future would be represented in your present, so you would still be pre-dicting the future in a strict sense.

Yehonatan

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:25 GMT
Thank you, this sounds very interesting? I presume it's discussed in your essay? I will take a look!

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H.H.J. Luediger wrote on Mar. 16, 2020 @ 21:39 GMT
Dear Emily,

"Of course, this way of thinking does depend on the assumption that there exists an external reality and there are objective facts about the laws governing it. If you don’t believe this, we’re unlikely to have much common ground."

I'd like to encourage you to think of the meaning of EACH of the the obove 39 words and then restate that " there exists an eternal reality and there are objective facts...".

Heinz (nonbeliever)

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:08 GMT
I'm impressed that you counted the number of words in that footnote! Which word in particular do you object to?

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David Brown wrote on Mar. 16, 2020 @ 22:58 GMT
"Where and how does the mathematics required to determine the dictates of the laws of nature actually get performed? Most physicists shy away from these questions, and not without reason – they are very difficult questions, and we don’t really need to answer them if our only concern is to produce correct empirical predictions." Consider 2 hypotheses: (1) If quantum probability distributions are irreducible then we get string theory with the infinite nature hypothesis. (2) If quantum probability distributions can be explained in terms of Fredkin-Wolfram information then we get string theory with the finite nature hypothesis. Have the string theorists underestimated Milgrom (as well as Fredkin and Wolfram)? What are the 2 greatest scientific predictions of the 21st century? My guess is that the answer to the preceding questions is the following: (1) The Riofrio-Sanejouand cosmological model is (approximately) empirically valid. (2) dark-matter-compensation-constant = (3.9±.5) * 10^–5 — contradicting Newton and Einstein (who assumed that this constant = 0). The vast majority of experts believe the Gravity Probe B science team — and not me — concerning the 4 ultra-precise gyroscopes — but are these experts correct?

"At Long Last, Gravity Probe B Satellite Proves Einstein Right" by Adrian Cho, 4 May 2012, Science

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:10 GMT
Thank you for your comments! Some interesting things to think about there.

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John C Hodge wrote on Mar. 17, 2020 @ 14:11 GMT
I suggest Survival is a goal of humanity. To act on another major goal is to fail at surviving. Knowledge about our surroundings aids survival. Animal behavior demonstrates they have some ability to know and predict events in their world. Humans study science and religion to better predict and then to cause events because it aids survival. Thus we get TV, cars and guns. History (another study area that helps predict social events) has demonstrated those that advance (make better predictions ) physics tend to survive and conquer other societies that don't advance science.

In the advance of physics, whenever a new set of observations is found, the first attempt at prediction is statistical. Thus when studies of disease started in the early 19th century, statistics help address the cholera disease before a microbe model was created. So to has Quantum Mechanics been created while awaiting a smaller particle model. The basic experiment to be explained is Young's double-slit (interference) experiment. The STOE (my model) has a computer simulation of a deterministic nature of Young's and other experiments that reject wave models of light.

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:12 GMT
That's interesting - I certainly agree that we have been too quick to jump to the conclusion that quantum mechanics is inherent probabilistic, but how does your model deal with the Colbeck-Renner theorem and similar results?

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John C Hodge wrote on Mar. 17, 2020 @ 14:32 GMT
I noted your paper "Underlying Assumptions in physics:..." on RG. The STOE also suggests the universe is NOT adiabatic isolated which follows the Quasi Steady State Cosmology (QSSC).So, the universe is NOT time symmetric. The STOE has yet to address entropy but I'm thinking about it. The one study I did looked at the CMB temperature. A feedback model was formed which calculated (the only model to do so) the Temperature to be withing a few microkelvin of the measured value. This model suggests the input of energy (also suggested by the QSSC) balances the outpu. Hence, "time symmetry" is really input energy balances output in physical systems.

I'll be loooking at a few more of your papers.

Thanks

Hodge

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Steve Dufourny wrote on Mar. 19, 2020 @ 10:16 GMT
Hello Dr Adlam,

I liked your general analyse , it is well said about these unpredictabilities and uncomputabilities due to our limitations. Limitations that we must accept with wisdom after all.It d be pretentious and odd to beleive that we have all the answers, we just know a so small part of our universal quant and cosmol problems. But we improve our knowledges each day after all in respecting a kind of pure universal determinism. Wish you all the best in this Contest, regards

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:14 GMT
Thank you! Yes, I certainly agree that it's important to recognise that our perspective on the world is limited and thus the laws of nature we are able to write down are not necessarily identical to the `true' laws of nature (whatever that means!)

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Harrison Crecraft wrote on Mar. 19, 2020 @ 15:20 GMT
Hi Emily,

Thank you for a well-written and thought-provoking essay. You present an excellent analysis of the problem of a purely predictive physics within the orthodox conceptual model of physics. Your examples (references [37, 38]) are very telling. Both cases “prove” that what nature does (or likely does) cannot be algorithmically decided in finite time. You offer two potential...

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Harrison Crecraft replied on Mar. 19, 2020 @ 21:04 GMT
Someone who reads to the end of my comment might rightfully conclude that an interpretation of physical reality that is objective, local, and causal violates Bell's theorem. I respond that the notions of locality and causality, described in my essay's reference [12], are more nuanced than in Bell's theorem, and that such an interpretation is fully compatible with Bell.

Harrison

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:15 GMT
Thank you for your comments! Your third way out of the problem sounds very interesting and I'll read your essay as soon as possible.

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Satyavarapu Naga Parameswara Gupta wrote on Mar. 21, 2020 @ 07:35 GMT
Hi Prof.Emily Christine Adlam,

Well written essay, after seeing your words .......after all, even if you are only interested in making predictions, you will most likely be able to make better predictions if you are using a theory which comes closer to the true laws of nature..................in the finishing part of the essay,

I thought I should ask you to see the predictions of Dynamic Universe Model's that came true. For that you dont mind seeing my essay “A properly deciding, Computing and Predicting new theory’s Philosophy” and give your learned comments please

Best

=snp.gupta

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:15 GMT
Thank you very much! I'll have a look at your essay as soon as possible.

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S.E. Grimm wrote on Mar. 21, 2020 @ 21:01 GMT
Emily, when I read the title of your essay some days ago I thought it was about the usual “stuff”. Nevertheless, I read your essay today and I am really impressed. I didn’t keep my code to rate essays but in my opinion it is a 10.0.

With kind regards, Sydney

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:16 GMT
Thank you very much, you're very kind!

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Dale Carl Gillman wrote on Mar. 21, 2020 @ 23:46 GMT
Hello Dr. Adlam,

- I enjoyed your essay. What are your thoughts on (local and non-local) hidden variables? (“…there are still physicists who argue that the conclusion of Bell’s theorem can be avoided, for example by the rejection of the statistical independence assumption[13], and if they’re correct then perhaps we can actually have both locality and determinism…”

- Do...

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:24 GMT
Thank you very much for your comments!

Yes indeed, I've thought a lot about retrocausality. Basically, I think there are two different `types' of retrocausality - either you can have both a forward and backward arrow of time, or you can just have global laws (e.g. optimizing some constraint over the whole of history) which implies that what happens at one moment affects what happens at all other moments, past and future. I agree that the first type leads to contradictions of the type you mention, but I think the second type avoids that problem because the global equations will necessarily be solved in a consistent way.

Yes, I enjoyed Dr Hossenfelder's essay very much. It's a very interesting question to determine exactly which problems of pure maths translate over into physical reality - I'm sure there are many applications which we are yet to discover!

Hmmm, interesting - my intuition is that undecidable problems would become decidable if you allow yourself infinite time to solve them, but I'm not aware of any results one way or another on this question!

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Flavio Del Santo wrote on Mar. 22, 2020 @ 09:59 GMT
Dear Emily, thank you for a very creative, well-argued and provoking essay. Although quite speculative, the ideas you introduce are remarkable and perhaps could help to oppose some form of scientific reductionism and take into serious account the possibility of more "holisitic" (in the sense of inputting the whole history of the Universe), as you say: "Insisting that all theories should...

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Author Emily Christine Adlam replied on Mar. 23, 2020 @ 20:07 GMT
Thank you very much for your incisive comments!

With regard to the arrow of time - this is a good point, and I certainly agree that the arrow of time does need to be explained. However, I don't agree that `predictive' (i.e. temporally directed) laws of nature are the only possible explanation for this phenomenon - it could, for example, arise from global time-symmetric laws together with...

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John David Crowell wrote on Mar. 30, 2020 @ 20:22 GMT
Emily I loved your essay. To me it is “on stream”. Probably because it describes what I did in developing the Successful Self Creation theory described in my essay. I got rid of all of the laws, rules, impossibles, etc. of current physics, started from a very different beginning and developed a theory with causes, retro causes and global causes in every SSC progression. In doing so I was able to derive a complete, mathematically consistent, explanation of the creation process that provides measurements that match the “generally accepted as true” measurements of the visible universe as well as the Planck measurements and the measurements of the major components solar systems, galaxies, etc.. In my derivation, I did not assume the laws and constants of physics were wrong - they just were not in existence before the beginning and are not in effect everywhere, all of the time and never change. The are created by the process as a component of the observed results. If you want to see your ideas put into actions and results read my paper. “Clarification of Physics: A Derivation of a Complete, Computable, Predictive Model of “Our” Multiverse”. While the paper may seem simplistic, the differences from current theories are profound. For example the process makes its own mathematics as a component of the processing, gets rid of infinities and zero which allows for a complete mathematical explanation. I would appreciate your comments. John

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John David Crowell replied on Apr. 8, 2020 @ 08:23 GMT
Emily I have “revised” my essay. In that revision I develop in more detail how the SSC processing produces its own mathematics and algorithms. The system in its encapsulation step also solves its own “halting problem”. It instills it’s own limits and boundaries. It solves the problems we are trying to impose on it. It creates its own temporal progression. In the revision I also extend the SSC fundamentals and their role in the other disciplines of science, philosophy, mathematics and religion. If you have already read the first edition of my essay, I suggest you read the revision and base your comments on it. John

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Author Emily Christine Adlam replied on May. 15, 2020 @ 19:56 GMT
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.

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Eckard Blumschein wrote on Apr. 16, 2020 @ 04:03 GMT
Dear Emily Adlam,

You might be surprised: My essay tries putting the pre into mandatory physics. That’s why I carefully read your essay. If I understand you correctly, you are hoping that accepting the weird retrocausal theory may yield better predictions by removing a constraint. Is there any evidence?

I suggest calculating for convenience as usual, as if Einstein was correct and the now that does distinct between pre and after, past and future was an illusion. While I like backpropagation NNs, my point is that the map, the theory including the laws of nature is not the territory, not the reality. My stance has unwelcome consequences. Do you feel in position to defend?

Regards,

Eckard Blumschein

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Author Emily Christine Adlam replied on May. 15, 2020 @ 20:20 GMT
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.

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Jonathan Kerr wrote on Apr. 17, 2020 @ 12:03 GMT
Dear Emily,

I think your essay digs around some questions that have become crucial in physics this century, and can be seen as part of a self-searching process that science is now engaged in. To some, it's an identity crisis, but however one takes it, it's very helpful to shine a searchlight on these questions, as you do.

I also tend to take an overview kind of position, standing...

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Author Emily Christine Adlam replied on May. 15, 2020 @ 20:12 GMT
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!

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Peter Jackson wrote on Apr. 17, 2020 @ 16:17 GMT
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

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Author Emily Christine Adlam replied on May. 15, 2020 @ 20:16 GMT
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!

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Edwin Eugene Klingman wrote on Apr. 26, 2020 @ 23:13 GMT
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

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Author Emily Christine Adlam replied on May. 15, 2020 @ 20:23 GMT
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!

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Michael James Kewming wrote on May. 2, 2020 @ 22:02 GMT
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

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Author Emily Christine Adlam replied on May. 15, 2020 @ 19:54 GMT
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.

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Member Markus P Mueller wrote on May. 15, 2020 @ 09:53 GMT
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

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Author Emily Christine Adlam replied on May. 15, 2020 @ 19:38 GMT
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).

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Member Markus P Mueller replied on May. 26, 2020 @ 12:32 GMT
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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Vladimir Nikolaevich Fedorov wrote on May. 18, 2020 @ 07:20 GMT
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

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Neil Bates wrote on May. 19, 2020 @ 03:59 GMT
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.

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