Talk:History of the Actor model

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[edit] Clarification badly needed

You wrote:

However, the notion of global times later proved useful in [Will Clinger 1981] for the development of a denotational theory for the Actor model because the fundamental orderings in the Actor model are invariant with respect to the frames of reference of (general relativity). The Actor model builds on the global times of General Reltivity instead of the more specialized global times of intertial reference frames in Special Relativity because experiments have verified the slowing of clocks in higher gravitational fields (see Gravity Probe A).

Looks like you are in the middle of rewriting this article, so I'll give you a chance to explain, but you need to convince us that you didn't misunderstand Clinger (or that Clinger didn't misunderstand Einstein). Yes, I realize that Clinger is your former student, but that doesn't mean you might not have badly misunderstood (or misrecall) something he wrote. I am not anxious to try to obtain the thesis and look for myself since I have other fish to fry; it is up to you to make sure you accurately present his views and that you stand on solid ground in choosing to present his views as established knowledge.

Also, I think you need to be very careful in expressing yourself; if you are completely unfamiliar with the way physicists use the words you are using here (which appears to be the case), you are likely to make a terrible mess of things. Right now, the quoted sentences are enough for an accuracy flag, so I hope you've removed or fixed them by the time I return.

As far as I can see from what you've said so far, you are really concerned with general problems of clock synchronization, but not with any aspect of relativistic physics per se. I think you would enjoy the recent book by Peter Galison, Einstein's clocks, Poincaré's maps: empires of time, which might help clarify this. You might also look for some preprints which have appeared in the last five years in the arXiv, speculating on the next generation of GPS type navigation systems. If you can explain yourself much, much better, you may want to strike up a correspondence with the authors. Best, CH (talk) 10:26, 16 September 2005 (UTC)

The article currently reads:
However, the notion of global times later proved useful in [Will Clinger 1981] for the development of a denotational theory for the Actor model because the fundamental orderings in the Actor model are invariant with respect to the frames of reference of (general relativity). The Actor model builds on the global times of General Reltivity instead of the more specialized global times of intertial reference frames in Special Relativity because experiments have verified the slowing of clocks in higher gravitational fields (see Gravity Probe A). If Moore's law continues long enough, there might be a detectable effects affecting the Actor model for satellites in highly elliptical orbits!
I am sure that the wording could be improved. You are welcome to consult the published literature on the Actor model including Clinger's dissertation. Probably the most important thing is that the fundamental orderings in the Actor model are relativistically invariant by design. Also Clinger [1081] settled an important conjecture about nonlocality in the fundamental orderings of the Actor model using the global times of relativity.
Thanks for the pointer to Galison. I will take a look.--Carl Hewitt 17:55, 16 September 2005 (UTC)
Prof Hewitt, respectfully, you will need to provide some substantial arguments from Clinger's thesis. Physicists and mathematicians understand GR in terms of a frame bundle which is a kind of fiber bundle on a pseudo-Riemannian manifold, or a Riemannian manifold. These manifolds may be of arbitrary dimension; GR is associated with a particular class of manifolds with a metric with a (3,1) signature. Are you stating that the actor model admit representations ONLY on manifolds with metric signature (3,1)? How about (N,1)? How about (N,M)? Can an actor model be laid out on a Riemann surface? How? details ... GR has a tangent space with a symmetry algebra of so(3,1). Does the actor model work only with so(3,1) or can it be made to work with any Lie algebra? Does it work on general symmetric spaces? Or maybe, because it singles out "time" as a special dimension, and time is conjugate to energy, and energy is described by Hamiltonians, and so actor models only work on symplectic manifolds?
Fortunately, Clinger's results do not depend much on the fine details of relativity theory. See below.--Carl Hewitt 06:02, 17 September 2005 (UTC)
I am personally aware of very specific theories that relate finite state machines to hyperbolic manifolds, but these are intricate, detailed theories on a firm mathematical foundation. (The relationship is through ergodic theory, which is associated with hyperbolic geometry, which frequently has SL(2,C) tangled into it.) But I do not get any sense from this article that these are the connections being pursued. linas 17:32, 16 September 2005 (UTC)

Thanks for your comments. The current version is quoted below. Your comments, questions and suggestions are appreciated.--Carl Hewitt 10:36, 17 September 2005 (UTC)

Clinger [1981] settled an important conjecture about nonlocality in the fundamental orderings of the Actor model using the global time of a frame of reference in relativity. Since the Actor model aims for universality, it builds on global times from General Relativity instead of more specialized global times of inertial reference frames in Special Relativity because experiments have verified the slowing of clocks in higher gravitational fields (see Gravity Probe A). If Moore's law continues long enough, there might be a detectable effects affecting the Actor model for satellites in highly elliptical orbits!

Clinger's results strongly depend on the globality of time for a frame of reference. If the astrophysicists determine that there is a fundamental problem with the possibility of time globality in our current universe, then the applicability of his results must be considered and the scope of the Actor model may need to be restricted to a locale, e.g., our solar system. This restriction would be unlikely to make any practical difference!

Indeed [ Asher Peres and Daniel Terno 2004] states:

In the present review on quantum information theory, we shall not attempt to use the full machinery of general relativity, with Einstein’s equations. We still consider spacetime as a passive arena, endowed with a Riemannian metric, instead of the Minkowski metric of special relativity. The difference between them is essential: it is necessary to introduce notions of topology, because it may be impossible to find a single coordinate system that covers all of spacetime. To achieve that result, it may be necessary to use several coordinate patches, sewed to each other at their boundaries. Then in each patch, the metric is not geodesically complete: a geodesic line stops after a finite length, although there is no singularity there.

Also by taking a dependency on both quantum physics and general relativity the Actor model may be "living dangerously" because of the well known difficulties in reconciling these two fundamental theories (see Quantum information and relativity theory).

Your usage of "global time" and "reference frame" do not appear to correspond to the way those terms are employed in the context of gtr, which raises red flags. You should probably look at Hawking & Ellis (see General relativity resources) with Clinger's thesis in hand to see if you can figure out exactly what he was talking about (if indeed he knew what he was talking about, which I must say I am starting to question). The bottom line is this: if you want to describe in Wikipedia articles some "theory" as part of the established scientific literature, you need to be able to cite published papers, including a review paper discussing a large and active literature concerning the theory in question. In contrast, as far as I know, the work of Clinger is entirely unknown in relativistic physics, and if so, you cannot accurately refer to subjects which do not yet exist in the literature.
The bottom line is that it appears that you are trying to write up unpublished speculations in a Wikipedia article, which is often dubious even extended speculations are described as such, and implying that these speculations consistitute and established field of research, which is inaccurate and unacceptable. I say againt: in my view, what you should be doing is writing and submiting a paper explaining your speculations to Class. Quant. Grav., which will enable you to get comments from expert referees who know the gtr lingo and literature. You should certainly study GTR at the first year graduate level first though, and I would suggest reading existing papers/preprints on the future of satellite navigation systems, since I guess your best bet of interesting researchers working in relativistic physics in your ideas might be to say something novel in this area. An additional reason why you might pursue this is that the papers I have in mind (search the arXiV) are themselves somewhat speculative.
(I myself will avoid taking on the role of a referee, since I have no professional obligation to do that and so far I don't see this as a worthwhile activity for myself. I am not trying to supress your ideas, just pursuing my own existence. For the same reason, I don't intend to look up Clinger's thesis so I can try to help you figure out if whatever he said really has anyting to do with gtr.)
Another warning: you may have fundamentally misunderstood the paper you cite: if you don't already, make sure you know about "Riemannian" versus "pseudo-Riemannian" or "semi-Riemannian" and "local chart" or "local patch" versus "global chart" (in general, a manifold may have no global charts at all, but always have infinitely many local charts whose domains may overlap). I am just guessing, but from the sentence you cite, it appears that the paper in question is talking about something quite different from what you want it to be talking about, so to speak.
A warning about behavior in Wikipedia: you should not have created the second category while a CfD vote was in process for the first one. This makes it appear that you were trying to evade a CfD vote and this is poorly regarded in the Wikipedia community. Such behavior could ultimately result in sanctions if you continued. Similarly if the vote went against you and you created yet a third category. If you write an article or create category and this comes up for deletion, you should argue your case in the VfD page and wait for the outcome before taking further action. If you haven't already done so, this might be a good time to read or reread a range of Wikipedia policies and guidelines to get a better feel for how to avoid upsetting other users.
No-one who is currently objecting to your activity here has any problem (as far as I know) with "interdisciplinary scholarship". The problem is that you are doing things backwards. First you need to establish the scholarly field which you think should exist (but which does not yet exist) by writing papers and generating a genuine literature in established journals with more than one author, with papers published in both CQG and CS journals. Yes, this could take ten or twenty years, but I can't help that. It's all part of the self-corrective nature of Science, which is one of the most powerful aspects of our subject. If you succeed in creating a new interdisciplinary field, once there is a review article of that literature, someone will no doubt eventually write a Wikipedia article on the subject.
Complaining about "supression" and using technical terms with murky but nonstandard meanings are both very bad ideas because this just makes you sound like a crank. Remember, PdN and I both said independently that we thought there might a germ of a useful idea somewhere buried in what you are trying to say, but to tease this out, I think you need to work on a speculative but publishable CQG paper with the help of their referees, after first having learned enough gtr to understand the preprints I mentioned which do concern clock synchronization.---CH (talk) 20:43, 17 September 2005 (UTC)

[edit] Pseudoscience

Based on Carl's answer to my questions:

Fortunately, Clinger's results do not depend much on the fine details of relativity theory. See below.--Carl Hewitt 06:02, 17 September 2005 (UTC)

I am forced to conclude that this stuff is pseudoscience, viz. it is fundamentally wrong. Carl claims that this stuff is "relativity" but when I asked him if space+time had to be 3+1 dimensional in his theory, or whether it could be some different set of dimensions, say, seven-dimensional space and three-dimensional time, a reply that this is a "fine detail of relativity" demonstrates a complete disregard of reality.

I'm sorry, but this guy is either not the real Carl Hewitt, or MIT should be considering disciplinary proceedings. This is scandalous and inappropriate behavior in the hard sciences. I have nothing against speculation, and have heard some of the wildest speculation come out from the mouths of the very finest. However, Carl seems to be unable to distinguish fact from speculation, and that iis very bad in an academic.

I'm planing on categorizing this article as pseudoscience. We need to figure out if this person is the real Carl Hewitt, and we need to talk to someone at MIT to find out what this is all about. I am pretty angry right now. linas 20:38, 17 September 2005 (UTC)

Oh wow. Linas, I've been pretty irritated by this too, and I although I missed the exchange you mention, of course I agree that this would be this mess into a crankier classification than would-be protoscience. However, let's give him one more chance.
Carl, I propose that you immediately remove the speculative portions of your articles claiming a connection to relativity and quantum physics, at least until such time as you and others have published papers in leading journals in those fields explaining your views. You could cut this material out of the articles and move it to your user page for the next few years.
Oh, another thing, Linas--- I understand why you feel that "Carl Hewitt the CS professor", versus "Carl Hewitt the crank" does not compute, but unfortunately, based on what I've seen so far, I don't question that the Wikipedia user Carl Hewitt is Carl Hewitt, Prof. Em. at MIT.
(Carl, frustrated cranks tend to get very sneaky and manipulative, so we too have had our bad experiences which are no doubt coloring our skeptical or even somewhat paranoid reactions, although I am trying to give a chance to back out of the mess you are making with your reputation perhaps somewhat damaged but more or less intact. Again, trying to put yourself in our shoes by imagining someone making weird claims about computer science might help you see that, emotional outbursts aside, we do have a point. The very fact that noone has spoken up in favor of your claims should tell you that this cannot be described as anything like established knowledge, or even as widely discussed speculation, as could be said for "information paradox".)---CH (talk) 20:58, 17 September 2005 (UTC)
It may be difficult for someone who has not read the published literature, but I am reporting on it. As I mentioned before, I can understand how many physicists feel burned by what the popular media have often done with their stuff. It's not been pretty.
You should not read very much into the fact that my colleagues have not yet shown up here. Many have indeed read the material that I have written and have commented on it in email communications among computer scientists. Just about everyone mentioned in the material that I have written knows about it.
In fact I recently gave a seminar at MIT on "The Present and Future of the Wikipedia in Academia" that was well received. I can tell you that my colleagues are extremely skeptical of the Wikipedia. They regard my efforts as a pioneering experiment. Typically they do not believe that the Wikipedia has sufficient social mechanisms to make it worthwhile for them to participate other than as casual readers of material of dubious accuracy.
P.S. Just notice the flag. Carl, I have to agree this flag is appropriate until you remove the objectionable speculations. I doubt anyone will object if you move that to your user pages and describe it as comentary or speculations which has been questioned by physics minded users.---CH (talk) 21:00, 17 September 2005 (UTC)

[edit] Article clarified

I have clarified the article. See what you think. Thanks, Carl--Carl Hewitt 06:53, 21 September 2005 (UTC)

Looks like you have replaced the original claim of an alleged connections to relativistic physics, which I thought suspect, with other stuff. That's all I care about, I think.---CH (talk) 20:45, 26 September 2005 (UTC)

[edit] Connections to quantum mechanics needs work

There are still some rather long sections that try to link quantum mechanics to the actor model that seem to not quite go anywhere or establish anything. In particular, here is a long quote from Einstein, there is a long quote about the EPR paradox, and there's a shorter quote about incompleteness.

  • I feel that this is not the correct article to ruminate about the interpretation of quantum mechanics. We already have a bulging category of such articles, at Category:Quantum measurement.
  • The inclusion of these quotes does nothing to establish any connection whatsoever between the actor model and quantum mechanics. From what I read here, I can only conclude that these are completely unrelated topics which just happen to be mentioned in the same paragraph. I just don't see the connection, and the article doesn't make one.

The discussion of QM doesn't seem to serve any purpose; I'd suggest cutting ou the quotes entirely. Isn't it enough to just say that the actor model was inspired by QM?

My complaint is that there is a standard, orthodox interpretation of QM, and that is that QM is described by a complete set of commuting observables in a Hilbert space aka a C* algebra. I can't imagine how anything the actor model might say would lead to this standard, orthodox interpretation. This is why I am question this part of the article.

Now, there's some slight implication that the actor model might make some sort of non-standard predictions? In that case, what are these non-standard predictions? Are they in accordance with QM, or do they contradict it? Have they been measured in a lab? If not, why not?

Let me rephrase. There is a statement that the actor model itself has certain "unobservables". This statement is far from obvious; it even seems wrong, and so this statement itself requires explanation. If, for example, an actor model was implemented in a matrix of several digital computers communicating via analog signals, then certainly, its quite possible to monitor the system completely. This is commonly done by chip design companies during prototyping stages, where giant chip emulators and simulators collect all sorts of info, without "disturbing the state of the observed system". In principle, every last bit can be monitored. So, in what way, exactly, is some part of the actor model not observable? linas 23:14, 26 September 2005 (UTC)

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