Essay Abstract

What questions can ever be answered by a physical entity? In this essay, we examine this question by studying the predictive powers of Laplace's demon. We find that the powers of a physical Laplace's demon are considerably diminished by limits on what is knowable due to quantum mechanics, (classical and quantum) chaos, incompleteness, and physical limits on computation. Because the helplessness of Laplace's demon naively conflicts with the shocking comprehensibility of the world around us, we imagine a new demon intended to model what questions can ever be answered. The approach and capabilities of this demon are found to strongly resemble those of scientists. We touch on some consequences of our arguments, including for free will and predicting versus understanding.

Author Bio

John Vastola is a fourth year Ph.D. student in the Department of Physics and Astronomy at Vanderbilt University.

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Hi John,

Great essay, I really enjoyed it!

I'm curious whether you are treating the idea of Laplace's demon as an equivalent to a Universal Turing machine? The five tools you equipped the demon with are very similar to the indelible tools of a Turing machine i.e read, write, process and memory. As you point out, the unanswerable questions of the demon are also undecidable problems of a Turing machine.

Michael

    Dear John Joseph Vastola,

    Wonderful essay on Laplace's demon!!

    I will make three or four posts on your nicely argued essay on different subjects. Each discussion will have its own thread, Ok?

    I worked and developed on Dynamic Universe Model for the last 40 years under Maa Vak's guidance, which is an N-Body problem solution, Mathematically stable,and many of its predictions came true. See my paper / essay here for further details...

    "A properly deciding, Computing and Predicting new theory's Philosophy"

    I did a lot of theoretical and practical experimentation on this model which gave positive results.

    With this introduction I will go for analyzing and discussing in the next posts

    Best wishes

    =snp

      Dear John Joseph Vastola,

      Subject: Flipping the wings of Black witch moth evaporates whole universe into vacuum!

      How such thing happens, then what happens to the all the matter in Universe, will change into energy by exploding into a Bomb???

      On what conditions it may happen for example like a Bigbang!!

      Thought provoking essay

      Best Wishes

      =snp

      Dear JJ Vastola,

      Subject: Laplace's demon, the hypothetical vast intelligence

      Your words:

      ......................First described by the eminent scholar Pierre-Simon Laplace in an 1814 essay. If the universe really did consist of nothing but a large number of particles obeying Newton's laws of motion, Laplace reasoned, then an intellect that (i) knew the positions and momenta of all particles at one time and (ii) could accurately solve Newton's equations of motion given that data, could know any future or past state of the universe with absolute certainty.............

      Main problem comes in Newtonian Physics or Einstein type Relativity based Physics is , they assume a single body and develop gravitation field around it in their own way. Multiple bodies of different sizes and different three dimensional positions are not taken.

      But in Dynamic Universe Model, a similar concept was taken, or in other words as what you mentioned in your essay posted as above, was taken about 40 years back. 132 bodies were taken, with some realistic positions and masses on a computer and tried to solve for exact positions and trajectories under mutual gravitation.

      Why 132 bodies you may ask. Then at that time i could afford to buy a Computer two floppy drives. In one I used to load lotus 123, and the second drive is filled with data .

      The same Model software "SITA" developed at that time worked well excellently. Solved all the problems, Ofcource, Now "SITA" is transported to "Excel"....

      Have a look at Blog...

      ' http://vaksdynamicuniversemodel.blogspot.com/p/blog-page_15.html '

      Please tell few words about this.....

      Best

      =snp

        Dear JJ V,

        I am continuing with another post.... Your words for reference.....Suppose for the moment that Newtonian physics offers the correct description of the universe, and that Laplace's demon knows the current positions and momenta of all particles in the universe to only Finite precision...............

        Now coming to "Dynamic Universe Model"

        I took all this work to be in Cosmology only, did not go into Quantum Physics; was under guidance by Maa Vak, took masses from NASA, Positions from Astronomical Ephemeris as on 01,01;2000 at 00.00 hrs as a starting basis for calculations....

        Dynamic Universe model calculates UGF the Universal gravitation force acting on a perticular body by all the bodies in the Universe at that instant of time for that positional setup. This UGF is not a constant, but varies with time and position, as all the bodies are moving DYNAMICALLY all the time.

        I hope this is clear....

        Best

        =snp

          Dear JJV,

          I forgot to add the precision in calculations is " 10-16 %" parts accuracy as available in Excel.

          Precision in measurement is may be " 1% " as the data available....

          Your comments please

          Best

          =snp

          Dear JJV,

          Your words.............. Laplace's demon knows the current positions and momenta of all particles in the universe to only finite precision instead of infinite precision; in other words, suppose that there is a small amount of error in its knowledge of the current state of the universe.

          How much does this initial inaccuracy affect its ability to predict the future, or retrodict the past? It turns out that most deterministic dynamical systems|like collections of interacting particles obeying Newton's laws|exhibit chaos, ...............

          NO CHAOs ANY TIME You verify published books and papers of Dynamic Universe Model........... !!

          Best

          =snp

          Dear JJV,

          I will stop for now, by seeing your response, I will discuss some more..........

          Best

          =snp

          I really appreciated this analysis and taking to task of Laplaces' demon. As someone unfamiliar with a lot of these examples I found myself still gripped and interested by the elegant and matter of fact writing style you had. It really made the subject much more tenable to grasp for all kinds of readers, something not easily done by many in your field. All in all an eloquent paper that satiated my curiosity while at the same time piqued my interest for more understanding of the other topics and examples you brought up.

          -M. Perry

            John,

            Quite a bit to unpack, John, but quite accessible and interesting. With somewhat of a liberal arts background, I appreciate the imagery of the black witch moth and the legendary specter of death it depicts. Chaos theory for this subject is appropriate as well. Like the way you characterize the problem the contest assigns. I like it that you don't pretend to know the answers but impose on us many relevant truths. One point suggested is that our cognitive powers have evolved to suit our environment, something I believe I touch upon, and our classical level perceptions have necessarily not incorporated quantum truths, which I also touch upon. My rating is your fourth, which I mention because we have an evaluator who gives 1s w/o comments sometimes choosing to time it with those who comment. I rate it among the highest.

            Jim Hoover

              Dear JJ Vastola,

              I really enjoyed reading your discussion and analysis of Laplace's Demon and quantum mechanics. You have a very creative style of exemplifying complex ideas into simple notions without losing the true essence of the concepts. Your essay raised many ideas in my head about the attempt of different mathematicians who attempt to come up with a single equation that describes the underpinnings of this universe, and in some sense, it made me think more about the P vs. NP problem as well. I know I am connecting all these things, but I am genuinely intrigued by the honesty reflected in your essay. Thank you for sharing your work.

              Best,

              SV

                6 days later

                Thanks for reading!

                That's a good question. Since, at the end of the day, Laplace's demon is essentially just a really high-end computer, you're probably on to something. I never thought about the parallels between reading/writing/processing memory and thinking/doing experiments, but they seem pretty striking now that you point them out.

                If there is any difference between them, it is probably only the moral difference that I'm emphasizing the demon's ability to 'think' in terms of different (possibly emergent) vocabularies. It calls to mind our own ability to do such a thing: how can we so adeptly switch between thinking about a shirt, its fabric, and the atoms that make it up? There must be a way to compute when it's appropriate to use one vocabulary or another, but it seems hopelessly difficult to pin down what that algorithm might look like in general.

                Thank you for the thoughtful comments! I'll definitely take a look at your essay.

                Judging the correctness of your theory is beyond my pay grade, I'm afraid. It looks very interesting, though.

                Thank you for the kind words, Jim. Yes, I found the imagery of the black witch moth (and some of the surrounding folklore) quite captivating as well.

                The point about our cognitive powers evolving to suit our environment is important, I think. I'm not sure what it would be like to wield a different set of cognitive powers, but I'm sure some kind of different brain architecture (or maybe even no centralized brain at all, a la jellyfish) is physically conceivable. And if it was appreciably different, maybe our ability to understand the world would be appreciably different too.

                I'll definitely take a look at your essay!

                Thank you for reading! Yes, it's fascinating to wonder about the possibility that we can describe the universe in complete detail via some equation or set of equations. What might that equation look like? Could we comprehend it? We can comprehend things like the Schrodinger equation quite well, but it remains to be seen whether it or something like it offers the full story.

                John,

                It's always good to see that someone reads your essay with some interest and with keen comments. I thinks it helps to promote the kind of analysis and thinking the foundation means to foster. Thanks, for reading and for your incisive remarks. I didn't get a chance to rate yours before, but I will now. It will be your 6th since people bomb at the time of comments.

                Jim