Hi Antony,

Thanks for the nice comments! I haven't thought much about black holes lately, but was just informed today how I might apply some of my ideas in that context, so maybe that will get put on the research list. I'll try to get to your essay as well.

Best,

Ken

Hi Paul,

Thanks! But I'm not sure I'd go so far as to say that 3D slices are "unreal", just incomplete. (After all, a 2D slice of a chair is certainly not "unreal", is it?)

You're absolutely right that I need a better description of what I mean by "dynamical evolution"; I probably neglected this because it was the main thrust of last year's essay entry, "The Universe is Not a Computer". So I'd recommend putting that on the top of the pile before tackling anything else.

Your phrase "bouncing back and forth in a timeless fashion" reminds me of how I used to think about retrocausal stories before I settled on the block universe as the only safe framework for coming to careful conclusions about such things. So I'd recommend putting Huw Price's book, "Time's Arrow and Archimedes' Point" on your list, which was the book that clarified many of these issues for me, and pointed me in some promising directions.

Best,

Ken

Hi Michel,

I'm glad you found it interesting. I didn't notice any obvious connections to that arXiv paper you mentioned, I'm afraid.

I'm not sure if my arguments allows one to "reject many arguments in favour of the 'it from bit' perspective", so much as attacks their key premise that there is no possible "it" in the first place.

And as far as contextuality goes, the story is complicated... You might read my exchange with Ian Durham on the issue, above.

Best,

Ken

Thanks, Howard!

High praise indeed... I was quite pleased to see (from your own essay, which I need to comment on, still!) that you've been grappling with the spacetime implications of the operationalist viewpoint. So I'll count the essay as a success if I can keep you thinking in those terms for a bit longer... :-)

I do think that reading Rob's essay from last year would be useful, but you might try my last year's essay as well. Rob's point -- that it's not so crucial whether one encodes the physics into the kinematics or the dynamics -- is perfectly fine *whenever there is such a dual interpretation available*. The fact that you can always seem to go back and forth for certain classes of theories is certainly interesting. But my point was (and is) that there are some classes of kinematics-only theories that *have* no dynamical version. (Or at least, if there is one, it's nonMarkovian and crazy-looking.)

Take the toy model in this essay, here. How would you couch the 5:4 vs 25:16 probabilities in dynamical language? I don't see any way that it could be done. And if I'm right about the parallel to the double slit experiment, then it's crucial to quantum foundations that one takes care to consider such kinematics-only stories that have no dynamical counterpart.

I wonder if your worries about a history-based story leading to decoherence are related to this point, in that getting rid of dynamics would avoid the problem. Certainly I would think the future-boundary conditions would help as well, so long as it's that boundary (the future measurement settings) that are effectively selecting out a particular set of histories to be overwhelmingly probable. (For an example of how this might work in practice, see IV.C of 1301.7012.)

As far as retrocausality vs. superdeterminism, I agree that they're similar in that they're both ways to break the Independence Fallacy... But I think that at any other level, the only way to confuse them is if one starts out thinking in retrocausal terms and then lapses back into forward-causal thinking. For example, in the retrocausal story, a future measurement setting M is naturally correlated with a past hidden variable L. But if you grant such a correlation, and then lapse back into forward-causal thinking, in cases where L clearly doesn't cause M you would come to the Reichenbach-conclusion that both L and M must be conspiratorily linked via some even further-past hidden variable. In the retrocausal story, no other variables are required.

For example, in my toy model, one *could* explain the story by linking the decision of the agent who selects the geometry (2A or 2B) to the hidden variables in the system, via some conspiracy, but it's so far from the stated explanation that it hardly seems possible to confuse those two options.

> And surely we *do* think we can predict, with high probability, that macroconfiguration from stuff in its past light cone...

The two answers here are that 1) "being able to predict in principle" and "being correlated in a specific, reproducible way" are two wildly different things, and 2) No, I don't think we can predict such configurations in general, even from a complete accounting of past HVs, because I've given up on the causal-determinism of dynamical equations. (Including stochastic equations.)

I realize that 2) may seem like a fairly drastic step to take, but I think my last year's essay provides a reasonably solid motivation for at least considering the possibility.

Thanks again for the kind words!

Ken

Hi Ken,

I finally got to your essay and gave it the best mark.

One minor criticism. A definition of dynamics would have helped less sophisticated readers like myself.

I invite you to visit my essay and see how I "give up dynamics", If you visit please be critical..... There is too much agreement around here.

Thanks,

Don Limuti

    Dear Ken,

    This is miles better!

    First of all, I'm glad that you don't think acceleration resolves the twins paradox. But I do wonder why you would use 'acceleration' rather than saying something like 'the boosted twin', especially since acceleration has been wrongly thought by many to resolve the paradox.

    But now to important stuff. I was talking with someone yesterday about my concerns with using verbs to describe space-time points, events, all of space-time, etc. What I learned was that a B-theorist uses the word "exist" non-existentially. Personally, I consider it nonsense to use language that doesn't actually apply to things by redefining words in such a convoluted way. Moreover, I think it leads to a lot of confusion, especially because it's so hard to not fall into the trap of thinking of these non-existential things that 'exist' as *existing*. (As an example, when you read what you wrote, don't you find it hard to not think of a *static* block? I think it's really hard to think of the block as a temporally singular, non-existential thing. I honestly can't make sense of "a thing that doesn't exist." Then I also have a tough time not thinking of existence *and* motion along the block when you write "updating is performed by a 3D agent over time"). And finally, I think if what's being proposed is so nonsensical that it can't even be properly described because the language comes to mean something else entirely, that's a pretty good indicator that it really is just nonsense.

    So what's my point: I do understand what you've written here, insofar as every time you say "I'm" you're really speaking non-existentially about what you "are". I'm actually pretty okay with the description until the last paragraph, because I don't think you're being too cavalier with your use of non-existential verbs until that point. But in the last paragraph, I think you're getting a bit carried away when you use three in a row ("updating is performed") in a way that tends to give the impression that you're not only talking of the block as something that 'exists' but doesn't really exist, but also of a sequence of updates that move up the world line.

    Alternatively, you could say (with the use of single quotation marks to indicate non-existential use of verbs) "The whole 4D block 'exists'. My world-line 'exists' in it. At each point along my world-line, I 'have' some knowledge of the entire 4D block; i.e., as I may 'know' something about past, present, and future events at each point of my world-line. At 'later' times, my knowledge of the block is more complete than at 'earlier' times." (I know "earlier" and "later" are adjectives, but I think it's good to still use the single quotes there). Maybe you could sum that up by saying, "one's incomplete knowledge of the 4D block 'is' a monotonically increasing function of one's worldline, where at each point along the worldline, that incomplete knowledge 'is' 4D".

    I think we're now on the same wavelength about what you want to describe, and I think the description of 'subjective updating', if stated carefully in this way, making sure to note the non-existential meaning of 'exist', etc., is about the best you can do. But then I simply have to wonder why you want it to be that way anyway. One reason, from our discussion above, might be that you don't like quantum non-locality. But I have a tough time seeing how a fear of existence in a world in which magic happens, can lead one to want to 'live' in a world where one doesn't actually *live* at all; where one doesn't actually *exist*. I think it's better to try to sort out our problems than just give in to unrealistic implications--and I honestly think a realistic version of quantum theory, or really quantum gravity, will come about after we've taken the more immediately necessary step of properly interpreting and understanding relativity.

    I guess that brings the discussion back to the one we were having above. Would it be at all possible to take that up again now? I think I've shown an ability to really understand this position that I think needs to be rejected, being very open to thoughtful consideration of its meaning and implications. I think you'll find if you do read what I wrote there, that I've given the same thoughtful consideration in coming to my own position on the matter.

    One more thing I wanted to say before I quit, in relation to the point you made early on about symmetry, is this: last night at the summer school on physics and philosophy of time that I'm attending, Stephan Hartmann gave a talk about the No-Alternatives Argument, which basically runs as, "Physicists have identified certain constraints, C, and have a set of data, D, that they want to use to construct a quantum gravity. To date, only string theory seems to meet all of C and D. Given the amount of effort that's been put into the construction of an alternative, we can be optimistic to some extent that there reall are no alternatives." The "some extent" is evaluated using Bayesian analysis.

    My objection to this entire line of reasoning comes in at the very beginning. It's true that having identified C, the usual goal is to try to construct a theory that adds C explicitly into the framework. But we know of cases in history, where ideas have been rejected for a long time just because they were naively thought to be at-odds with some constraint or other that people thought necessary to hold onto. For instance, given a butterfly's ability to easily flutter about, or even the fact that the Earth retains its atmosphere, people felt quite strongly for a long time that the Earth has to be fixed at the centre of the solar system, and this constraint was violently held onto (e.g., Bruno). But then Galileo showed (with a simple thought experiment that didn't even need to be conducted) that butterflies can flutter around just as well in the cabin of a ship, as they can when it's back at harbour, and it was realised that this constraint wasn't necessary to the realisation of the data, and the Solar System could, for all that constraint had mattered, be heliocentric. In light of what I've written about symmetry above, I would like you to consider that perhaps the standard symmetry constraint of modern physics maybe is being made too explicitly, for all the observed symmetries that must be reconciled.

    Cheers,

    Daryl

    Dr. Wharton

    Richard Feynman in his Nobel Acceptance Speech (http://www.nobelprize.org/nobel_prizes/physics/laureates/1965/feynman-lecture.html)

    said: "It always seems odd to me that the fundamental laws of physics, when discovered, can appear in so many different forms that are not apparently identical at first, but with a little mathematical fiddling you can show the relationship. And example of this is the Schrodinger equation and the Heisenberg formulation of quantum mechanics. I don't know why that is - it remains a mystery, but it was something I learned from experience. There is always another way to say the same thing that doesn't look at all like the way you said it before. I don't know what the reason for this is. I think it is somehow a representation of the simplicity of nature."

    I too believe in the simplicity of nature, and I am glad that Richard Feynman, a Nobel-winning famous physicist, also believe in the same thing I do, but I had come to my belief long before I knew about that particular statement.

    The belief that "Nature is simple" is however being expressed differently in my essay "Analogical Engine" linked to http://fqxi.org/community/forum/topic/1865 .

    Specifically though, I said "Planck constant is the Mother of All Dualities" and I put it schematically as: wave-particle ~ quantum-classical ~ gene-protein ~ analogy- reasoning ~ linear-nonlinear ~ connected-notconnected ~ computable-notcomputable ~ mind-body ~ Bit-It ~ variation-selection ~ freedom-determinism ... and so on.

    Taken two at a time, it can be read as "what quantum is to classical" is similar to (~) "what wave is to particle." You can choose any two from among the multitudes that can be found in our discourses.

    I could have put Schrodinger wave ontology-Heisenberg particle ontology duality in the list had it comes to my mind!

    Since "Nature is Analogical", we are free to probe nature in so many different ways. And you have touched some corners of it.

    With regards,

    Than Tin

    Hi Daryl,

    I'm glad we're coming to some agreement... And yes, it's not exactly fair to deny the use of the verb "to be" to B-theorists by insisting on an A-theory definition! (There's a "Be-theorist" joke in there somewhere...) I'll encourage you go re-read some of that piece by Price with this fact in mind.

    > As an example, when you read what you wrote, don't you find it hard to not think of a *static* block? I think it's really hard to think of the block as a temporally singular, non-existential thing. I honestly can't make sense of "a thing that doesn't exist." Then I also have a tough time not thinking of existence *and* motion along the block when you write "updating is performed by a 3D agent over time"

    I *try* to think of a static block, because my innate-but-wrong time intuitions are too strong to fight any other way (you'll best be able to fight your "motion" intuitions in exactly this manner). The DVD example is useful, but perhaps not going to help you. Maybe the idea of a 4D block in the mind of a 3D person may help, although this 4D block isn't real in the same way that the actual universe is. What it really comes down to is that you don't *need* to think of the block as temporally singular; after all, it's not, any more than a full description of the universe written on a blackboard is spatially singular. (One needs different language to talk about the representation vs. the actual; perhaps where we're getting into all of our linguistic problems.)

    > But then I simply have to wonder why you want it to be that way anyway.

    What I "want" has nothing to do with it. That's what relativity tells us. Sure, I can go down your road of denying certain features of relativity, but "why do you want it to be that way anyway?" :-)

    Your last point about starting from bad premises is right on target with me -- after all, that was the topic of last year's contest, and I effectively wrote about this very issue. But this point is *only* salient if most people are indeed making the wrong assumption. So when I look around at quantum physics and see that 99.9% percent of theories are assuming a dynamical framework, and 0.01% are analyzing histories 'all at once', I don't see myself on the side of a widespread but wrong assumption. Physicists implicitly break time-symmetry in their ontology all the time, often without even realizing it. I happen to think it's the common-sense, A-theory side of things that's the impediment to progress, precisely because it's far too easy to fall into that style of reasoning without thinking it through carefully.

    Okay, I'm running out of time (ha) before I'm off to a conference, but I'll head back up to that first comment on simultaneity and see if I can say anything useful.

    Best,

    Ken

    Thanks, Don! I'll try to get to yours as well; I see it's very highly ranked.

    Yes, I definitely should have gone more into the definition of "dynamics", but perhaps was overly shy of rehashing last year's essay.

    Too much agreement...? See above. :-)

    Best,

    Ken

    > I'd ask how it is that that *doesn't* appear to be inherent in the phenomena? I mean, if all the information we ever receive is *always* about events that occurred in the past, and that is about phenomena that never appear to be influenced by future events, then how does a past-future asymmetry *not* appear to be inherent in the phenomena?

    Because every microscopic process is time-reversable. (read: time->CPT for precision.) You're talking about macroscopic arrows, which can be traced to low-entropy cosmological boundary conditions, not asymmetric laws. If you ask me what breaks the symmetry of the boundary conditions, I'll answer that we're now asking the same questions, and on some days I'll start speculating if perhaps they're not broken after all. (As for our knowledge about the past, consider what we would know about the future EM field if our eyes were actually atomic-recoil detectors, detecting their own emissions instead of absorptions.)

    If there is a cosmic rest frame defined by distant events, then this view is somewhat nonlocal, right from the start. And it would seem to be rather convoluted to keep maintaining this rest frame near black holes. I'll note without comment that your "common sense" examples seem to be posed in the Earth's frame, not this cosmic rest frame.

    I'm not sure the rest of your comments can be better addressed than via what I've already said, above and below. (You start getting into this "exists" business above, which we're coming into some agreement on below.)

    Finally, I will caution you that I recently learned there is a term "time snob" as applied to A-theorists who believe that only *they* take time seriously, and who believe that B-theorists don't take time seriously. So don't be a time-snob. Or an existence-snob. :-)

    Thanks again for all your careful thoughts on the subject, and I hope we will continue to agree to disagree, if only to encourage us both to be as precise and careful as possible.

    All the best,

    Ken

    Dear Ken,

    Kindly indulge me. Probably no better place to clarify things with the experts than this forum.

    Is it being implied by the relational view of space and as suggested by Mach's principle that what decides whether a centrifugal force would act between two bodies in *constant relation*, would not be the bodies themselves, since they are at fixed distance to each other, nor the space in which they are located since it is a nothing, but by a distant sub-atomic particle light-years away in one of the fixed stars in whose reference frame the *constantly related* bodies are in circular motion?

    You can reply me here or on my blog. And please pardon my naive view of physics.

    Accept my best regards,

    Akinbo

    Dear Ken,

    Thank you so much for your posts. It means an awful lot knowing that you feel you've benefitted from this exchange, as I certainly have. Honestly, I really hope we can continue to agree to disagree, because for me it's all about getting things right, and being precise and careful at every step is such a huge part of that. In that regard, I don't know if it could be more beneficial than to have an opponent who truly understands and can appreciate both sides of the argument for what they are.

    I have some specific responses to what you wrote. Copying isn't working on my phone, so I'll only quote a few words.

    >if there is a cosmic rest frame...

    Is a whole 3d space that exists any more non-local than a 4d block that 'exists'? Also, Shelly Goldstein sure gave a persuasive argument last night in favour of Bohmian mechanics.

    >And it would seem to be rather convoluted...

    Do you have Hawking and Ellis handy? Can you flip to the section on spherically symmetric gravitational collapse? It refers to observers O and O', and there's an E-F diagram... Consider the implicit definition of time that's being used--I.e. the variable they use to refer to time's passage. You know I think there's an objective time variable for the whole universe. It's not the E-F advanced time parameter. In any case, I think we both agree that descriptions of actual temporal passage are inconsistent with einsteinian notions of the relativity of simultaneity, which is what they're implicitly assuming--I.e. they give a dynamical account of temporal passage while assuming a physical definition of simultaneity that's inconsistent with that.

    Now look at the statical coordination of de sitter space in the images I posted above. The r coordinate becomes imaginary at the coordinate singularity. It's simply no good after that, for all t. I talked about this with Gordon Belot today, and he thought Felix Klein showed that this was the right way of interpreting the line element. I actually think the Schwarzschild 'event horizon' is also such a coordinate singularity. Remember, I think space-time is globally hyperbolic at a fundamental level.

    Now, to get back to the E-F description. Do you have Kip Thorne's black holes and time warps? He recalls a conversation with Lipschitz, where he called Finkelstein's paper a revelation that lifted a fog (or something like that). It was what convinced Wheeler that black holes exist, etc.

    Personally, I find all of this convoluted. I think you can only have my sense of existence or your sense of 'existence' and neither admits of the dynamical emergence of black holes in the universe. I think it's entirely inconsistent.

    >I'll note without comment...

    Ah, but I'm allowed to conduct my thought experiments assuming absolute simultaneity in the Earth's rest-frame due to the principle of relativity. The important thing in assuming a cosmic rest-frame is whether the empirical evidence supports that. Right?

    >Finally, I will caution... (whole paragraph)

    :) Can I say I feel justified to be just a little snobbish about these things, insofar as I personally think a non-existential definition of "exist" (and all other verbs) is a convoluted and misleading way of speaking, which has led to a mountain of confusion (by the way, a good chunk of my essay is devoted to discussing this)?

    Again, thank you so much for discussing all of this. I can't tell you how much it means to have the opportunity to debate with you. It's been very clarifying. By the way, do you think Greene is really thinking non-existentially about the block? It seems to me in the quote I posted below, that he's really emphasizing the block's existence.

    Best regards,

    Daryl

    Dear Ken,

    Replying to post on physical basis for introduction of principle of least action (dated Jul. 13, 2013 @ 10:41 GMT)

    Having (time x change), or (time x energy) comes naturally by way we introduce the principle of least action. But this introduction is done on the level of effective systems, i.e. not at fundamental level at all. The bigger picture, with places to introduce spacetime as one piece on both low and effective levels, is painted in http://www.fqxi.org/community/forum/topic/1597 Notice there that notion of time is connected to the system, i.e. it is not a global time (can we call it local time?). And since it is not a global time, a little special place of time in Lagrangian method does not produce global problems, which none of us want :) .

    De facto, when we look for a new theory (i.e. suggesting new Lagrangian), we watch out not to have bad things like negative energy. And, although it is beautiful to have complete time-space (t-x) symmetry, we avoid certain theories specifically based on this aspect of time being experimentally a little different.

    Sincerely,

    Mikalai

      Hi Ken,

      OK, a little more in the way of a response to your response:

      1. I'm still not sure that what Eddington is talking about is unphysical. He's just talking about probability theory. Chains of probabilities are naturally asymmetric. It's just the way they are. Which leads me to...

      2. Again, I think relativity is mis-interpreted. The arrow of time is built into it via the very fact that the sign of time in the metric is opposite that of space. It's easier to see if you work through relativity graphically using diagrams, but once you see it you can't "unsee" it, as they say. The only way to make time perfectly symmetric in relativity is to either drop the basic notion of cause and effect or allow for things like complex-valued masses and strange things like that. So, in short, I think it's incorrect to say that all the laws of modern physics are time-symmetric. They're not.

      Ian

      Hi Ken (and Howard),

      As an addendum to the things I mentioned above, what occurred to me while reading Howard's comments was that, in a nutshell, I think we're overcomplicating things by missing the obvious. I know the retrocausal approach has become quite popular, but, again, it seems to be based on a certain set of notions that we seem to be clinging to for dear life --- the time-symmetric nature of modern physical theories, the absolute correctness of the Standard Model, etc. --- and I have no idea why. Again, I don't think the Standard Model needs replacing. I just see it like I see most theories: it is a highly accurate description of a limited set of phenomena. [And for the sake of people who don't want to go digging for my other comments, relativity is simply not time-symmetric. There's a neat little gedankenexperiment that you can do with a type of light clock that shows that if you run it backwards you don't get the Minkowski metric. You only get it if you run it forward in time.]

      Ian

      *Lifshitz. Sorry. I think it was him and not Landau, but he was talking about Landau as well, I believe. It's been a while since I read that, though. By the way, I'm not thinking of geodesic incompleteness, anymore than there is geodesic completeness past the coord singularity in dS space, described in those coords.

      Hi Wharton,

      I like the trend that this essay encompasses about not dwelling on the spacetime view of things and also its emphasis on returning to the big picture. It put some critical controversies in history in a more viewable, and relate-able, light.

      Thanks,

      Amos.

        Dear Professor Wharton

        Do you have opinion about my essay?

        Yuri

        Ken,

        We agree. In my "It's Great to be the King" I tend to satirically rebuke the Anthropic Principle, especially "It from Bit.

        For example, you say, "where everything about the present was encoded in some initial cosmic wavefunction," I deny the existence of consciousness w/o a body during the BB and bodies not possibly existent until 1 billion years after the BB after heavier-element stars.

        The connection between consciousness and reality and the subatomic and the macro worlds I say are philosophical / metaphysical with their arguments. They are confused in attributing similar behavior to micro and macro, much like your concept: "case quantum information can plausibly be about something real . Instead of winning the argument by default, then, \It from Bit" proponents now need to argue that it's Better to give up reality. Everyone else need simply embrace entities that fill ordinary spacetime - no matter how you slice it."

        Thanks for a well-thought-out read. I am interested in seeing your thoughts on my essay.

        Jim

          Dear prof. Wharton,

          Your statement, "with no objective 'now', there is no objective line between the past and the future", indicates the causality of "microhistory", and implies discrete-time.

          With this, dynamic time evolution in configuration space is adapted in string-matter continuum scenario, in that one-dimensional observer for one-dimensional source is ascribed to express the emergence of other dimensions with realistic information continuum rather than probabilistic that indicates the observational plausibility of real-time information continuum on molecular dynamics of simplex in linear time with reference to holarchical discrete time.

          With best regards,

          Jayakar