Hi Flavio,

I like your essay a lot -- well argued and well written! Very nice food for thought!

Perhaps two remarks / questions:

1. I suppose that your main hypothesis is quite independent of the specific construction of FIQs? Probability theory would probably give you many alternative ways to implement finite information quantities, without spoiling your conceptual conclusions?

2. Your remarks at the end of Section IV are somewhat disjoint from the rest. Isn't this all about the interpretation of conditional probability, P(A|B), as what you can *learn* about A given what you know about B, not as causal influence? I didn't really get the point of this part.

Otherwise I enjoyed reading it a lot!

Best,

Markus

    Dear Markus,

    thanks so much for your kind apprecition and comments, which I will try to address.

    1. I fully agree -if I understand correctly what you meant- that the model of FIQs we construct is just one possibility. In fact, there could be many more approaches to formalize the concept of finite information quantities. In particular, the attribution of a propensity to each digit could perhaps be replaced by some different mathematical modeling. One concrete way is the one that Gisin is currently pursuing (partly together with me) of considering intutitionistic mathematics. How exactly "probability theory would probably give [me] many alternative ways to implement finite information quantities" is not clear to me. I would be glad to discuss this, should you have any thoughts on this.

    2. Admittedly, the last paragraphs of my Section IV are not spell out in as much detail as I would have liked. The aim there was to briefly comment, mostly as a matter of completeness, on the logical relation between determinism and causality. Following the philosophical tradition of probabilistic causality, which I extensively quote, in fact, there seem to be consensus that while determinism implies causality, the opposite does not hold. I have myself stated this in an older paper. Hoowever, I recently found out (thanks to D'ariano's pupil Marco Erba) that in the paper I cite they disprove this belief. This gave me a lot to think, and I am now quite convinced that neither determinism implies causality nor causality implies determinism, but for a reason more elementary than the ones the authors of that work claim. Unfortunately, I have perhaps been not clear enough in explaining this in my essay. But I am working on making my thoughts on the subject matter more clear.

    All the best!

    Flavio

    Flavio,

    Good essay. Well written & pertinent. I certainly agree the option that nature is causal without being entirely deterministic.

    A couple of questions;

    How do you see the question of "exchange of momentum", and so OAM 'vector addition', as a key measurement criteria?

    And, can you provide me a link or link to a paper regarding the finding I recall from the Vienna web site a few years ago that "after interaction there is no memory of previous polarisation." I assume that hasn't changed?

    I agree that digging down to the deepest foundations is required, and indeed present some interesting results from dong so in my own essay.

    Well done,

    Peter

    4 days later

    Dear Flavio Del Santo,

    Isn't a child, an effect resulting from more than just a single cause, father and mother? In other words, weren't reductionist monotheism and the following to it physics naive when they believed in just one cause and in particular in initial conditions?I got the impression, your conclusion confirms Karl Popper. You and me seem to entirely agree with him.

    However I slightly disagree when you wrote:"Again, determinism assumes that given an initial state of the universe and universal laws everything causally follows. But this is misleading because there is only one specific initial state and, without alternatives, causation seems avoid concept. On the contrary, indeterminism introduced ...". Creationists need an initial condition. Are there any consequences?

    Alan Kadin might be wrong. Nonetheless, if he is correct, this will have serious consequences.

    Regards,

    Eckard Blumschein

      "constructive mathematics, perhaps intuitivism, seems most promising."

      Perhaps you meant intuitionism?

      Dear Flavio,

      I thought your essay was very good, and enjoyed reading it. When tackling questions like these, it's good to remove any myths and false ideas at the outset.

      I think with classical physics, what many thought would turn out to be fully deterministic was not just the known laws, but also future physics with the undiscovered laws. They were probably wrong, but that's why Laplace said "...an intelligence which could comprehend all the forces by which nature is animated...".

      There's also the risk, though it doesn't invalidate your points, of looking back at classical physics with the hindsight of quantum theory, and finding things (particularly at a small scale) that didn't add up as a result. So at times you may be updating classical physics to align it with more recent discoveries. But some excellent points, and in distinguishing between the different approaches that still exist to some extent within our present ideas, you clarify physics generally. To me, the issues about determinism also raise questions about block time, and the tension between that and the open future of QM.

      What you say about chaos theory is very relevant - incidentally, some recent work, referred to in my essay, shows that some chaotic paths (of the three-body problem modelled with black holes) cannot be traced in principle, due to the limitation of the Planck length.

      You gave my earlier essay on 'what is fundamental' a high rating, and we had a good exchange. At the time I could only hint at my interpretation for QM, but since then it has been completed, this time it's outlined in my essay. It's a new approach, and a documentary has been made partly on it, with a conversation about the interpretation with Rovelli. It adds, or attempts to add, a further layer of explanation underneath RQM. As I see you work in quantum optics, you might find it of interest.

      With best wishes,

      Jonathan

        Dear Jonathan,

        thank you for your comments and inputs.

        I will have a look at the filmed conversation you had with Carlo and at your paper soon. Will come back to you if I have something sensible to say.

        If fact, my research and main interest is not at all quantum optics, but foundations of quantum physics.

        All good wishes,

        Flavio

        Hello, I have put this post because I find this totally odd , you don t merit this kind of comportment, so I wrote this on the blogs

        Hi FQXi, it is totally not neutral the comportment of one or TWO members inside the community, because Del Santo was First with 13 or 14 votes with 8,4 and now with one or 2 votes he is at 7,9 , What is this stoty, of memebers prefer the bad compettion instead to be neutral and rational so we understand why this planet does not turn logically, this kind of comportment shows that this memeber is not a real universal generalist, I don t understand how it is possible inside a Community of conscious and intelliegnt persons, it is a shame because the member has probably put a 0 , see in your algorythms this member because he does not merit to be in your team,simply lets name a cat a cat,Friendly

          Dear Dufourny, I truly appreciate you stepping up for me here. Some time ago when I was first in the partial rating Dmitri Martila wrote me a comment stating that he rated my essay "not so well" and gave me a 1 (the minimum you can give!). The other day, without even leaving a comment, one person gave me 1 again. No much to say, it's just unfortunate to see people feeling this initiative as such a competition that makes them act dihonestly and irrational.

          It would be much better if the votes were not visible during the rating period, because they only introduce a strong bias on the judgement.

          Thank you again for the support!

          Flavio

          You are welcome, these comportments irritate me a lot and I don t know why FQXi accept this, they could maybe sort the fake searchers, You merit to have very good votes simply and it is a game but we must be just and neutral.

          I have put this too on blogs

          Frankly let s consider the human conportements and the Vanity because it is totally sad. These comportments prove that the person having made this is nor a generalist nor a universalis, maybe just a simple intelliegnt for some details prefering the competion and strategies without really understanding the real meaning of the theory of Game. For me this comportment does not merit to be a member inside the FQXi Community and maybe you could change the algorythms to have a pure tyransparence , like that we can see who are the real universalists, just, logic , neutral and the others forgetting the basis. Even If I had a problem with a searcher, never I d make this, I d be neutral and just. We know why this planet is in this state, just due to these comportments at big scale for decisions. Can we accept this , is it democratic, no I don t Think, these persons decrease the velocity of evolution and they just satisfy their Vanity.

          My best regards, and I repeat your essay is one of the best and it is sad to see the comportments against your essay, they don t merit to be members of FQXi simply, take care

          Thanks Flavio,

          and great to hear that your main interest is quantum foundations. I don't know if you'll like my interpretation, but I hope so, I do think your work is among the best I've seen on this site.

          About the conversation below, yes, there's someone going through the new essays and marking them down - several have had only one rating, of 1/10. The problem with that is, others tend not to read it if they see a rating of 1, so it stays like that. Mine was given that soon after being posted, I don't know if they even read it. Ah well... J

          6 days later

          Dear Flavio,

          I don't know if you've read my essay yet, but when you do, I'd appreciate it if you'd rate it - just for relevant/interesting, you don't have to agree with it, though I'd very much like to hear any comments. It has only had one rating so far, and people aren't reading it as a result, even though Carlo found what's in it interesting.

          Thanks a lot, best regards,

          Jonathan

          Flavio,

          This was an excellent read. Very clear, which I value highly. Thank you for the work put into this.

          Could I ask what your stance is on the many-worlds interpretaion is, if you take one? I saw your footnote about it, but as you know, it ended there.

          Thank you,

          Ernesto

            Dear Ernesto,

            thank you so much for your kind words.

            Frankly, I don't like the many-world interpretation very much. Firstly, as Carlo Rovelli always puts it, there is a cost for every interpretation that you have to be ready to pay. Many worlds has an enourmous ontological cost, for it requires to assume this irrisonable moltiplication of worlds, universe, or whatever. Secondly, interpretations not only provide a consistent backstory to a theory, but are also supposed to solve some conceptual issues. In particular the interpretaion of QM should address the nptorious measurement problem. The many-world interpretation claims to provide a nice (deterministic) solution, but this is clearly not true. Indeed, whiile it "solves" the problem of which outcome occurs and has even some arguments on how probabilities emerge from determinism (so, it somehow recovers the Born rule), it does not tell when the branching occurs.Why the universe splits when you go in the lab and activate a photodetector, but not in most ofother interactions?

            I hope this addressed your question. All of this, however, is not really pertinet to my essay.

            Thank you again and all the best,

            Flavio

            Flavio,

            Yes, it was a tangential question, but I appreciate you taking the time to answer. I like your point of view.

            Best,

            Ernesto

            Dear Flavio,

            I enjoyed reading your essay! It's well written, well documented, and interesting, giving a fresh perspective on classical mechanics. And I loved the way you concluded, with the epistemic modesty coming from the acknowledgment that both classical and quantum mechanics can be interpreted both deterministically and indeterministically, without the experiment being able to tell them appart.

            You wrote: leave the dynamical equations of Newtonian mechanics unchanged

            Considering that you reject the ontological principle of infinite precision, what do you think happens with the dynamical equations of Newtonian mechanics? Should them also be replaced with some computable dynamical equations?

            Your essay raises many interesting questions. Some of them are of course related to my own interest. One is the following. Do you think that in classical mechanics indeterminism enters at various times, as part of the dynamics, or only in the initial conditions? This interests me personally because of the way I see quantum mechanics, but I decided to take this part of discussion in private, since I think your FQXi page should stay about your essay.

            Thanks for the great reading, and I wish you success in this contest!

            Cheers,

            Cristi

              Dear Cristi,

              thank you very much for appreciating my work! Indeed, my main motivation is to show that what is considered one of the greatest novelties of quantum mechanics, indeterminism, is not necessarily inherent in that theory. I don't claim, of course, that there are not fundamental differences between classical and quantum theory, but one can surely be more thoughtful and symmetrize the situtation a bit than is customary in textbooks.

              As for your comment on the dynamical equations, this is a very good point. In my previous [link:arxiv.org/abs/1909.03697]paper[link], with Nicolas Gisin, although we have focused primarily on relaxing the principle of infinite precision, by acting on the initial conditions, we briefly discussed possible modifications of the dynamics. I report you here the passage that we wrote about this, because it still reflects what I think about that:

              "The laws of motions are fundamentally stochastic. In this case, however, we cannot speak of an interpretation of the theory, but an actual modification of the formalism is required. In fact, in this case not only chaotic systems but also integrable ones would exhibit noisy outcomes, leading to experimentally inequivalent predictions. This case is the analogue of spontaneous collapse theories in quantum mechanics [22-25], which modify the Schr ¨odinger's equation with additional non-unitary terms."

              Of course, as you hint at, one can also combine two levels of indeterminacy, both at the level of the dynamics and in the initial conditions. Yet, so far I have deliberately focused on the latter case only, because I wanted to maintain the formalism unchanged and only play with interpretations thereof.

              Thank you once more, and I wish you the best for the contest too!

              Cheers,

              Flavio

              Dear Flavio

              I think that, in one way or another, we (physicists) have been aware that the way we are mathematically representing our physical experience has not been the most suitable. For instance, (1) measurements always have an associated uncertainty that arises from the limited resolution of the instruments. (2) It is assumed that the measurement process does not affect the system under study. (3) Physical objects are extended objects. All of this is ignored in the mathematical representation of classical physics. The novelty that I see in your essay is that by a deep and well documented analysis you are showing a way to relax this problem. You are setting an equilibrium between experience and mathematical representation. Your essay and the work behind have the potential for a breakthrough in physics. In my view, it is also a knock down to modern mathematics which, as Scott Guttery argues (another participant), has been completely disconnected from experience, and it is better for us to invent our own mathematics.

              My essay discusses how physics has given too much importance to mathematical representation and measurements on top of our physical understanding, perhaps you will find it interesting.

              By the way, just as feedback, to my knowledge the photoelectric effect was discovered in 1887 by Heinrich Hertz, you say that in 1895 no quantum effect was discovered. Congratulations for your great essay, I am sure it will make to the finals.

              Best Regards

              Israel

                Dear Israel,

                I am flattered by your compliments on the potential you see in my modest work. I am glad that you find it interesting. I will look at your essay as well and comment if I have something to say about it.

                Best regards,

                Flavio

                6 days later

                Dear Dr Flavio Del Santo

                Thank you for presenting a wonderful essay... Your words ..... classical physics (i.e., Newton's mechanics and Maxwell's electrodynamics) would allow, in principle, to predict everything with certainty.....are very much true in case of Dynamic Universe Model. Many of its predictions came true.

                Let me hope you will have time visiting my essay to have a CRITICAL examination of my essay... "A properly deciding, Computing and Predicting new theory's Philosophy".....

                Best Regards

                =snp