Dear Noson,

This is a very interesting paper, brilliantly written as might have been expected from you, and food for thought. Very Kantian, in a way. It struck me that the overall idea, that human limitations induce the unpredictability of quantum mechanics, is quite explicit in the Copenhagen Interpretation as originally intended by Bohr and Heisenberg, namely (as I try to explain in detail in the Introduction of my 2017 book): the need for a classical description of the apparatus leads to the uncertainties in QM. However, you seem to believe this is true in all of physics. I doubt this myself, and your examples rather show that often one uses idealizations where in principle one could be more precise. The point of QM (but only of QM) is that in principle one cannot be more precise. I am increasingly beginning to believe that we should incorporate intuitionistic mathematics into (quantum) physics in order to deal with such issues.

But overall, anything stressing human limitations in setting boundary conditions on science has my deepest sympathy! All the best, Klaas

    Dear Jochen,

    I am sorry I did not write earlier. All the structure in the universe has gone out the window.... We live in crazy times.

    You wrote "I don't believe (although some do) that this structure has any existence beyond its being instantiated in concrete objects---so this is rather more an 'Aristotelian' than a Platonic picture."

    In what sense is this structualism then? Why not call it nominalism? How does your structures really exist?

    I will get to your essay soon.

    Be safe!

    All the best,

    Noson

    Dear snp.gupta,

    Thank you for looking at my essay.

    I will look and comment on your essay soon.

    All the best,

    Noson

    Thank you. I hope you got positive responses. The more the merrier!

    All the best,

    Noson

    Dear Jim,

    Thank you for the kind words. I will look at your essay soon and comment on it.

    All the best,

    Noson

    Dear Edwin Eugene Klingman,

    I plan on reading and commenting on your essay soon.

    It, indeed, looks interesting.

    You wrote: "This is compatible with my belief that physicists project mathematical structure on the world and then believe that physical reality has this structure."

    You might want to look at an old essay where I write about this.

    https://fqxi.org/data/essay-contest-files/Yanofsky_Why_Mathematics_Wo_1.pdf

    All the best,

    Noson

    Dear Israel Perez,

    Thank you for taking an interest in my paper.

    I have no reason to believe that we live in some "simulated illusory reality". The lack of objects is a fact of existence in this world. Thankfully, it is us who make objects of things.

    I look forward to reading your paper. I will read it and comment on it soon.

    I love Bohmian mechanics. I am not sure it is correct. But I hope it is. Be that as it may, what I said about quantum mechanics stands for Bohmian mechanics also.

    The Kochen Specker theorem shows that even with Bohmian mechanics, objects do not have properties till they are measured. The only thing that Bohmian mechanics adds is some type of determinism, not value definiteness.

    All the best,

    Noson

    Dear Klass,

    Thank you for the kind words.

    I hope you and yours are safe and healthy in this strange and dangerous universe that we live in.

    I will comment on your paper soon.

    All the best,

    Noson

    Noson,

    I am rating those I have missed today. My rating will be your 7th. I say this because there is someone who gives a 1 w/o comments.

    Jim.

    Dear Noson

    Thanks for your reply. I appreciate it. Perhaps it was not your intention, but the way you expressed it left me with that impression. Nick Bostrom put forward the simulation hypothesis some years ago; I definitely do not see a point in this hypothesis. If our reality is simulated or not, makes no difference in the way we live.

    Best wishes!

    Israel

    9 days later

    Dear Noson,

    yes, I am finding it hard to juggle the multiple conversational thread on here, and balance it with the general craziness of the world out there. The world has undergone a strange phase transition since this contest began.

    Regarding your question, my structuralism, following Russell, is essentially an epistemic one---I don't believe that 'structure is all there is', as an ontic structural realist does, but rather, that our scientific inquiry tells us only about the structure of stuff---for instance, events that reliably correlate with one another, how things react when prodded (i. e. in experiment), and so on.

    This sort of structuralism is threatened by Newman's objection: if that's truly all we can say about the world, then all we can say about the world is exhausted in statements of cardinality. Against this, one can hold that in experience, we have 'direct access' to the intrinsic properties of the world, which singles out a preferred structure, which overcomes Newman's objection.

    In this sense, that structure of the world that's appreciable to us in experience does have an objective character, and thus, I would not call it nominalism---it's not merely a conventional issue. The ordering relation embodied by the books on my shelf is something that's real. I could define all sorts of other relations on that set---just take any collection of pairs of books, or triples, or what have you---, but they wouldn't necessarily connect to anything out there, and thus, be conventional---nominalist---in this sense.

    Does that make sense to you?

    Hope you're staying well!

    Cheers

    Jochen

    14 days later

    Dear Noson,

    I was first reluctant to read your essay, because I am not interested to learn how our mind imposes limits on physics. Or is it the other way round? I am interested to learn, how the world is. But I must agree with you, we can't.

    I certainly also agree that our mind performs incredibly well in ordering the world. And also that the naive, object like reality we attribute to our sensations is a construction of our mind. Also Poincaré shows, that our mental reconstruction of the outside world distilles the invariant features of our mulitdimensional sensory input. The description of the sensory input as a process is also a mental reconstruction (by the way).

    But I do not agree with the consequences you take. And here I want to start to promote the view I take in my essay.

    The main critic is an inconsistency in the argumentation: in a way you seem make a point, that the underlying reality is not the way we picture it and on the other hand you seem still to assume the existence of some true reality, that is not knowable, but to which you compare the minds reconstruction as false, approximate or illusory.

    Of course if there is no such thing to which our models can be compared, then the notion of truth becomes somehow vague.

    Regarding the mental reconstruction, I have another view. Since we and our mind are part of the physical world, our mental constructs got it approximately right for the specific environment. "The ship swims." is a good an true proposition, if we live in a world, where there is water and gravity. The meaning of 'ship' lies not in how it is composed, but in his mesoscopic properties.

    Regarding the classical physics, you are certainly right. They apply on systems that must be completely isolated from the rest of the universe. Ideally empty. But this separability is a necessary approximation to have well defined properties and objects and well defined laws. Then we are able to model the environment as disturbance. If these disturbances are to strong, such that the approximation does not work any more one might need look for other separable systems and objects. For new concpts. (More on this in my essay.)

    This approximate applicability of concepts and laws might be all there is. This means that these concepts are neither illusory nor false.

    I might have twisted your words a bit in order to make them fit my argument. Sorry for that. Last but not least you wrote an enjoyable, well written, thought provoking essay.

    There is nothing one could do better.

    Good luck in the contest.

    Luca

      Dear Noson,

      What is the world made of?

      This issue does not affect the problem of "the Ship of Theseus".

      Because the Universe is a mathematical creation, which does not change.

      Regards,

      Branko

        Noson,

        Hope you have time to check mine out before the deadline: https://fqxi.org/community/forum/topic/3396

        Jim Hoover.

        Dear Professor Landsman, Dear Professor Yanofsky,

        Kindly permit me to comment on Prof. Landsman's suggestion that QM cannot be more precise. I respectfully disagree. QM has not been tested at higher energies, in particular at the Planck scale. Prof. Stephen Adler and I have independently developed theories [Trace Dynamics, Spontaneous Quantum Gravity] in which there is a deterministic matrix dynamics at the Planck scale. When this theory is coarse-grained over time intervals much larger than Planck times, there emerges, at lower energies, quantum theory, along with its indeterminism. Quantum indeterminism is a consequence of coarse-graining an underlying deterministic theory. Pretty much the same way that the apparently random [Brownian] motion of a pollen grain in a glass of water is a result of coarse-graining the underlying deterministic motion of water molecules. I like to say that nature does not play dice at the Planck scale.

        I am currently reading Prof. Yanofsky's absorbing essay, and hope to share my thoughts on it subsequently.

        Thanks and best wishes,

        Tejinder

        Dear Professor Yanofsky,

        It was a pleasure to read your well-written and enjoyable essay relating limitations of physics to the working of the human mind. I wholly agree that how the world around us appears to us must also have to do with how the mind functions and interprets the world.

        I have a comment on the said quantum indeterminism and the so-called collapse of the wave function during a measurement. As you may know, the Ghirardi-Rimini-Weber theory of spontaneous localisation provides a dynamical explanation for collapse of the wave function. The collapse is still random, but is now a law of nature, even if phenomenological.

        More recent research shows where spontaneous localisation comes from, and why it is random. The guiding principle for understanding this is: coarse-graining an underlying deterministic system can induce apparently random behaviour in the emergent dynamics. This is what is happening to quantum mechanics: it is a coarse-grained approximation to a deterministic matrix dynamics operating at the Planck scale.

        Thus perhaps this property of QM and classical world [absence of macroscopic superpositions] can be attributed to the mind not being able to probe very small length scales, without supporting experimental technology.

        My thanks and best wishes,

        Tejinder

        Professor Noson,

        I learned a great deal from reading your Outer Limits of Reason just as I have learned much from reading your current essay.

        You have a way of expressing complex philosophical ideas in concise, clearly understood language that I deeply admire.

        Best of luck in the contest!

        Rick Searle

          Noson - Thanks for your essay. I admire your work, and I enjoyed your essay. I agree that the idea that the structure of the mind imposes itself on the world it interacts with is a powerful insight. What I did not see you address are the inherent limitations on mind that you so carefully articulate in The Outer Limits of Reason. The firm fixtures of incompleteness and complexity that beset the mathematical also beset the mental, and hence our understanding of the physical. Perhaps (as I suggest) these limitations are fundamental in all realms (mental, mathematical and physical) and that the qualities of autonoetic consciousness carry throughout: entanglement, agency and self-reference.

          Good luck!

          George Gantz: The Door That Has No Key: https://fqxi.org/community/forum/topic/3494

            Dear George,

            You are right. There were some types of limitations that are not a product of our mind. For example, limitations caused by self-referential paradoxes seem to be inherent in the universe rather than in the mind perceiving it. There are many different types of limitations. In this essay I focus on the limitations that come about from our minds.

            I look forward to reading your essay and commenting on it.

            Thank you.

            All the best,

            Noson

            Dear Rick,

            Thank you for the kind words.

            I look forward to reading and commenting on your essay.

            Sincerely,

            Noson Yanofsky