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ttn

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  1. I have a 2 and half year old I read to every night. Currently we enjoy Where the Wild Things Are, Curious George, Margaret Wise Brown and Eric Carle books. I recently discovered Oliver Jeffers children's books which we like very much. Anyone else have any good recommends for me?

    Check out the "frog and toad" books by Arnold Lobel. There are four different books that I know of, each with five or six short stories. They're fun and well-written in general, and a few of the stories (e.g., "the kite" from "days with frog and toad") have particularly good philosophical themes.

    We've also really enjoyed some of Robert McCloskey's books, especially "one morning in maine" and "blueberries for sal". Nothing particularly Objectivist or philosophical about these, but they're good stories with some nice science/nature-ish and pro-values themes, and they have a very calm, measured style that I find refreshing.

  2. I did study it, up until the point I grasped that any reverse wave theory contradicted the results of the Aspect experiment. It doesn't take a PhD to make it that far, so I have my doubts about what the PhD's that can't even reach that conclusion are really up to.

    Objectivism comes into this in the following fashion: once one understands a particular idea is false, it is immoral to continue to act as though it were true. It becomes difficult to continue to associate with those who do not yet grasp their mistake, even if they are not immoral.

    Well said.

  3. Let's see... catching up...

    Thomas, there is no need for you to apologize to me. If anything, Lewis Little should apologize to you and others who got, from his writings, a very wrong impression about the state of contemporary thinking in the foundations of physics. Little works very hard to make it sound like he is the first person in the history of the universe to think that orthodox QM is a bad theory, that physicists' positivist and operationalist and anti-realist and anti-causal tendencies are unscientific and wrong, etc. Actually this kind of misinformation is a crucial part of his sales pitch. If people understood, for example, that Bohm (and to a much more significant degree, Bell) shared these sorts of reasonable motivations, they would first-handedly explore those other thinkers and find there the kind of serious scientific work that, well, makes TEW look like embarrassing crackpot nonsense by comparison. So, Thomas, I'm glad I helped you get unswindled. That's precisely the sort of thing I wanted to achieve by investing this time writing publicly about TEW. I hope others get a similar benefit from this thread.

    Then there's this historical question:

    I don't think I've ever seen the derivation of psi; I just know that Schrödinger came up with it, but I'm not sure how. And he didn't think of it as a probability function. So, how did he come up with it?

    It was Louis de Broglie who really first came up with the physical idea of waves somehow guiding the motion of associated particles. Actually, de Broglie came up with pretty much the whole "pilot wave" theory (i.e., what is sometimes today called Bohm's theory or Bohmian Mechanics) before the eventually-orthodox "quantum mechanics" was created by Heisenberg et al. For anyone really interested in the history here, probably the best source is "Quantum Theory at the Crossroads" by Valentini and Bacciogallupi, which I think is still forthcoming, but an earlier draft of the whole book is available for free on arxiv.org. Anyway, Schroedinger's contribution was "merely" to cook up a mathematical equation to describe the time-evolution of the waves de Broglie had already postulated. His physical interpretation was that |psi|^2 represented a mass or charge *density* for the electron. This is more or less still the picture that is taught to chemists... remember those pictures of fuzzed-out electron "clouds" surrounding atoms from your high school chem textbook? That was Schroedinger's theory. Of course, it is false, or at least very misleading. It was Max Born who introduced the now-standard "probability interpretation" of |psi|^2. I haven't studied the history here *really* carefully, but Born's writings have always struck me as seeming to presume a very good, de Broglie-ish understanding of the *meaning* of the probabilities -- that is, Born tends to speak of the probability of *finding* an electron at a certain place (with the implication that this is a mere passive revealing of a state of affairs that obtained prior to one's looking), as opposed to the eventual Copenhagen view that the looking itself causes the particle to (for the first time) acquire a definite location. That is, Born's own views don't seem to be as stupid as the views that are usually attributed to him in (e.g.) quantum physics textbooks.

    By the way, and just because someone made a remark that suggested some confusion about this, there is nothing whatsoever wrong with interpreting |psi|^2 as the probability for finding a particle. This is true according to both Copenhagen and Bohm. The rightness or wrongness is to be found in the underlying physical theory and the role that this probability plays in the theory. For example, in Copenhagen, psi is taken as a complete description of the physical state of the system, but it really is never clear if that means there is a real physical wave, or if psi is merely some kind of "complete description" of the *knowledge* a person can have about the system, or what. And probability enters by magic, i.e., as a special (actually contradictory) postulate about what happens when a "measurement" occurs. So the problem with Copenhagen is not the probability interpretation of psi, it's the ontological unclarity and the "unprofessional vagueness and ambiguity" created by the tension between the two different sorts of laws pertaining to "measurement" and "non-measurement" situations (whatever those are supposed to mean exactly). By contrast, in Bohm's theory, psi is a real physical wave, which guides the trajectory of real physical particles according to a clean and clear mathematical law which applies all the time no matter if someone is "measuring" something or not. And it turns out that the probability of finding a particle in a particular spot is proportional to the intensity |psi|^2 of the wave at that spot. What possible basis could there be for complaining about that? Maybe that clarifies something for someone.

    Let's see. I also wanted to respond to another bit of ridiculousness I saw on the speichers' site. PhilO there recommended Joy Christian's recent papers purporting to have refuted Bell's theorem. This just proves that PhilO is merely an ignorant partisan in this debate. His recommendation is equivalent, say, to some unthinking person hostile to Objectivism (and who has never seriously studied any philosophy) casually recommending the recent "refutations" of Rand on the Maverick Philosopher website. I suppose I should actually say something about what's wrong with Joy Christian's "refutation" of Bell, else I will be accused of flinging empty ad hominem. OK, fine. His whole paper is based on the *stupid* idea of making the A's and B's (from my derivation of Bell's theorem in the book review which began this thread) into non-commuting numbers. Thus, he contemplates theories which predict that, for a given physical state of the particle pair and given orientations of the two polarizers, Alice's photon will yield outcome "A" and Bob's photon will yield outcome "B" -- but where "A times B" is not necessarily equal to "B times A". Now if you for one second take your head out of Plato's heaven and remember what these symbols A and B are supposed to mean, you realize that this is completely stupid. The whole thing is a brilliant example of what's wrong with so much of theoretical physics today. It's impeccable and sophisticated mathematics that makes perfect sense so long as you completely and totally forget that you are supposed to be doing *physics*, which requires that you remember *what you are talking about*. Anyway, in the paper Joy Christian does a nice little algebraic dance with these non-commuting numbers, and shows that the correlations (which remember are calculated precisely by multiplying the A's by the B's and then averaging over various things) can exceed the limit expressed by Bell's inequality, and in particular can agree with the experiments. So it is supposed to be a counterexample to Bell -- a locally causal theory which nevertheless makes predictions consistent with the experiments. It is no such thing, because the theory's *actual* predictions for the experiments are not even wrong -- which I actually mean here in its literal, as opposed to rhetorical, sense. A wrong prediction would be one that says a given particle goes up when in fact it goes down, i.e., that says A = +1 when actually A = -1. That's a wrong prediction. What kind of prediction do you have if your theory says that the value of A (which remember denotes whether a certain particle goes up or down) isn't *either* of +1 or -1, but is instead some kind of mathematical operator which fails to commute with other similar operators? Such a "prediction" does not rise to the level of achieving a wrong prediction.

    The lesson here is that if you want to actually make a useful contribution to discussions on these issues, you have to do a little more than spend 5 seconds googling for "Bell theorem refutation" (or however PhilO found this paper) and then posing like you understand the issues and have read the relevant literature. There's a name for people who do only that: frauds. To save PhilO some of his valuable time in future rounds of the debate, here are some other completely stupid things he could google up and cite to his fellow ignorant crackpot-supporting friends as bolstering their position: the infamous Hess/Phillipp "refutation" of Bell's theorem, Ghose's various (proposed) experimental "refutations" of Bohmian Mechanics, Bohr's "refutation" of the EPR argument, etc.

    Since this thread seems to be dying down (which I do not consider a bad thing), let me also underscore some of the high points of the discussion so far.

    1. Three or four times in the past, Little has put forth detailed attempts to predict, using TEW, the correct predictions for the EPR-Bell type experiments. Each of these specific proposals has been retracted (sometimes amid great rhetorical displays of dishonesty). In his new book, Little simply dodges the whole issue, presenting a bunch of misguided polemics against Bell and Bohm, and *not* presenting any actual demonstration or calculation to back up his (empty and false) claim that TEW can correctly account for the results of these experiments. It can't. If it really could, Little would have shown us how. This is not the case of a theory which "has yet to address" a certain point. It is a case of outright fraud and evasion. Think I'm wrong? Then you can win a thousand of my dollars.

    2. We can be certain, even without knowing anything about TEW other than that relativistic local causality is one of its foundation stones, that TEW is false. Bell's theorem and the results of the relevant experiments prove that no such locally causal theory can make the right predictions for these experiments. Any proponent of TEW who wants to be taken seriously by serious people must first acquire and then display a genuine understanding of Bell's work. Lewis Little should lead by example here. Of course, anybody who did acquire that understanding would then necessarily cease to be a proponent of TEW.

    3. In probably my most important post in this thread, I explained in some detail how TEW in fact cannot even account for the results of the two-slit experiment (which TEW's advocates, including Little, universally take as the most clear-cut and most dramatic evidence in favor of the theory). This deserves a serious response from anyone who wants to maintain that TEW deserves even a moment's further consideration. One of the innocent young things who posts to the speichers' site should raise this question there and see what kind of response follows from the theory's last-remaining supporters.

    4. People need to understand that, even leaving aside for the moment the question of TEW's truth, Lewis Little as a "commentator" on foundational issues in physics, simply cannot be trusted. He badly misunderstands (really, just fails to even approach proper understanding) and/or deliberately distorts Bell's work. Same for Bohm's theory. And same for the orthodox/Copenhagen views. If you think Lewis Little is some kind of original or important thinker because he had the courage and intelligence ("north of 200"!!) to stand up to the corrupt physics establishment, you simply need to grow up and get out more. Every crackpot in the history of the universe has tried to create precisely this same impression, and typically succeeds in fooling a few foolish people. Don't be foolish, people, and don't get fooled. Especially when you are wearing your Objectivist hat.

    5. Being ignorant about a given field is OK. But being ignorant *and nevertheless supporting embarrassing crackpot garbage from a field of which you are ignorant, and doing so qua Objectivist* is not OK. If a self-proclaimed Objectivist got interested in astrology, or the magical healing power of crystals, or intelligent design, and started talking about their wonderful "alternative to scientific orthodoxy" on Objectivist websites, listing the crackpot originators of such theories as "experts" on forums for ayn rand fans, linking to stupid refutations of darwin, etc., the appropriate response of sensible Objectivists would *clearly* be to SHUN and REPUDIATE these people. This is what should happen to TEW supporters.

  4. In your original post you didn't appeal to the novel feature of Aspect-like experiments at all, only the results of EPR-Bell type experiments.

    By "EPR-Bell type experiments" I just mean the experiments of Aspect, Weihs, and the other similar ones that are specifically designed to test Bell's inequality. So there must be some sort of confusion here (perhaps my fault) if you thought I was referring to something *other* than Aspect's experiment here. Hopefully all is clear now.

    That this is a fundamental fact of reality and therefore important, is the most significant content of your original book review not merely the "negation of the negative" of refuting TEW in the eyes of that book's intended audience (laypersons). The positive value of your original post is primarily that it teaches an unfamiliar truth, only secondarily that a particular falsehood is pointed out. You could have followed the path of pointing out that reverse wave theories are ruled out by Aspect, but that would not teach anything about locality. I'm glad you composed the argument as you did, otherwise I for one would not have learned anything new.

    It's certainly true that the fact that relativistic local causality (i.e., "locality") is refuted by these experiments is an important and surprising discovery. Most physicists are still in denial about it, which I guess puts the TEW crowd (for once) in good company.

  5. Travis , it seems obvious to me ,but there seems to be some confusion as to what you mean by "non-local". Some think you are asserting the following :

    [1]. "instantaneous action" of any kind [as opposed to simply "supraluminal"]

    [2]. "super positions" as in two locations at the same time.

    [3]. That a particle is "everywhere and nowhere at once"

    [4]. That a partical can travel from [a]. to . without crossing the space in between.

    I think this will clear up a whole lot of confusion for others.

    Don't confuse confusion with the desire not to know.

    But, since it's so simple, here you go.

    By "non-locality" I mean (unless the context specifically indicates otherwise): faster-than-light causation, of the sort ordinarily thought to be prohibited by relativity.

    Perhapsa further comment I made on HBL last night would be worth adding: "the whole idea of instantaneous action-at-a-distance is a complete red herring -- it should *never* have been in play in these discussions at all. That it has been (and [...] continues to be) is only a result of obfuscation and misinformation on the part of TEW's supporters. Whether the misinformation campaign is deliberate, or merely based on ignorance, is irrelevant. If one is ignorant enough of the technical details to be able to innocently proffer that kind of misinformation, one shouldn't proffer it. And of course nor should one do so if one knows better. Given that there is such misinformation in play, people watching from the sidelines and trying to decide whom to believe need to be extremely cautious. There is such a thing as a sensible-sounding argument whose (perhaps tacit) premises are total fabrications and distortions of the truth."

    I hope that clarifies. Though I can guarantee you that certain dishonest individuals will, no matter how many times this is explained to them, continue to insist that what I really mean by "non-locality" is ... something other than what I do mean. Such people are not interested in the truth and, after a point, can no longer be dealt with rationally.

  6. I'm pretty sure now that the Aspect experiment is why I personally ruled out TEW back in the day. You could have appealed to Aspect in your original post, but chose not to. I could guess why, but so long as you are here it would better if you could explain why you chose the more general, but harder to understand refutation over the more specific but easier to grasp refutation. (Yes, I am presuming Aspect is easy to understand, in that the idea that the photons can't change after they are produced is easy to understand.)

    I'm not sure exactly what you're asking. Are you asking why I didn't appeal to Aspect, but instead appealed to the more recent Aspect-like experiment done by Weihs et al in Innsbruck in 1998? If that's it, there's no real reason or answer. The later experiment is just better, though in ways that probably don't matter for the level of the discussion here. Appealing to Aspect instead would have been equivalent. Or did you mean: why didn't I appeal to experiments (like Aspect's) at all? If that's it, I think the answer is: I thought I did. It's certainly a crucial piece of the puzzle. The way we know that faster-than-light causation exists is precisely from the Aspect (and other similar) experiment(s), interpreted using Bell's theorem.

    I understood that up until the parenthetical "in addition". There multiple types of non-local causation? As mentioned above I'm reading further into this.

    Well, multiple types of non-locality maybe. The two that were in play in this discussion were the following. The first type was the sort of "nonlocal state description" that one has explicitly in QM, in which (for example) two spatially-separated entities (like the two photons in an EPR-Bell experiment) fail to have individual distinct polarization states, but are instead part of a sort of holistic, joint 2-particle polarization state. Then the second type of non-locality is the non-local *causation* shown to exist by Bell's theorem and the associated experiments. Note that there isn't really any *causation* involved in the first type of non-locality. So the point I was making was that one directly practical reason Bell probably formulated the theorem the way he did (and this is in addition to the fact that it makes the theorem *stronger*, which other things equal is obviously a good thing) was to be able to show clearly that the nonlocality proved by the theorem is *not* the (familiar, subtle) sort that is manifest in QM (and not in any *obvious* way in conflict with relativity theory), but is instead a more blatant non-local *causation* which *is* obviously in conflict with relativity theory -- or at least with what everybody took to be an implication of relativity theory all those decades.

    Hope that clarifies. If not, it's probably not worth pursuing. It was really only a pointless speculation about why Bell presented something one way rather than a slightly weaker, but maybe more physically transparent, other possible way.

    Got it. Possible followup questions on the way if you choose to stick around.

    Sure. I won't be reading and posting as much as last week, but I'd be happy to answer any of your follow-ups about this stuff.

  7. Thomas, we're going in circles, so after this post I won't discuss it any further. Your point seems to be that it's a logical fallacy to infer from "Mr. X is an Objectivist" and "Mr. X believes special-scientific theory Y" to "Y is part of or endorsed by Objectivism." That's of course true. But don't you agree that it's nevertheless reasonable for some honest person to form a negative judgment of Objectivism if he sees someone (who loudly proclaims himself an Objectivist) endorsing and proselytizing for a bunch of dishonest crackpot garbage (and worse, doing so at least in part on nominally Objectivist grounds, e.g., by citing Ayn Rand's statements about causality)? People do, and should do, this kind of thing all the time. It comes down to what I said before: it is not unreasonable to assume that a person's actual cognitive functioning reflects his explicitly endorsed epistemological beliefs. So if a person claims to be an Objectivist, but can't tell the difference between good science and pseudo-science (e.g., say, they are into astrology and the magical healing power of crystals), rational observers will be inclined to infer, validly if wrongly, that Objectivism itself is pseudo-scientific.

    You keep mentioning Rand's alleged agnosticism about the theory of evolution. (I'm not really sure where this claim comes from, hence "alleged.") But there's an important difference between *not* taking a position on some scientific issue because one doesn't have the expertise to take such a position (which is what AR supposedly did), and *taking* a position *despite not having* the relevant expertise. I think I have made it clear from the very beginning that the people I mean to criticize are those who are ignorant of physics, but nevertheless respond to the superficially-Objectivish-sounding sloganry in Lewis Little's writings by forming a favorable judgment of TEW as a scientific theory. People who are ignorant of physics and know it and so refrain from forming a favorable judgment of TEW (or Bohm's theory or any other theory) will catch no flack from me.

    You wrote: "If you want to get to the epistemological method of TEW and show that this is wrong, and that it could not have come from a rational approach to science, then that is a different (though related) point." That is precisely what I have been showing.

    You wrote:

    So, yes, insofar as a scientists makes a claim that flies in the face of reality, philosophy can veto that conclusion. And if one follows evidence and reason and non-contradictory identification, that theory will be more accurate in its epistemology, but still Objectivism qua philosophy can't say whether the conclusion is right or not. It is not the job of philosophy to do the special sciences, except to outline the general rational approach and epistemological methods. There is a limit as to what philosophy covers, and philosophy per se does not cover whether Bohm or TEW is correct in the particulars.

    I'm sorry, but this is just the same old false dichotomy. Yes, physics is not deduced from philosophy. We all get that. Neither is, say, the question of whether the alignment of the stars and planets has a causal influence on human activities. But does that mean that if some crackpot astrologer gains a following among some self-described Objectivists, we should all just turn the other cheek and say "well, if anyone forms a negative judgment of Objectivism based on this, it's their problem, not ours, since astrology isn't part of philosophy and they should know that." Clearly not. The right response is to repudiate the crackpot and his followers and ask them to please take their crazy pseudo-scientific nonsense as far away from Objectivism as possible.

    You wrote: "I don't know enough to reject TEW". Don't confuse "rejection" with "lack of endorsement." Actually, this is an example of an important point in Objectivism, namely, that there isn't a symmetry between the positive and negative. (Knowledge is not the same as a lack of ignorance, you don't build by refraining from demolishing, etc.) If you don't know enough about physics or TEW to have a positive position one way or the other on any of the relevant options, it is OK to simply not have a positive position. Don't endorse TEW, don't endorse Bohm's theory, don't endorse my/Bell's interpretation of Bell's theorem, etc. That, ultimately, is all I'm asking of anyone. I'm *not* asking anyone to take my negative judgment of TEW (involving, as it does, certain advanced technical things like Bell's theorem) on faith. (Though I have to also say that there is plenty of evidence, available to any honest non-expert, that Little is a dishonest crank, so you don't actually need to understand fully how to prove that TEW is false, to know that it and its author and supporters are embarrassments to and dangers to Objectivism.) All I'm asking is that people who don't know enough physics to (say) answer the many objections I've raised, be honest with themselves, and refrain from endorsing and proselytizing for TEW, especially under the banner of Objectivism.

  8. An additional note for windows users:

    If you can translate '03BB" into decimal, you can hold down the Alt key and type that number on the keypad (not the numbers at the top of the keyboard.) Character map should supply this, BTW, but you can use the calculator (Open calculator, view in scientific mode, toggle the Hex radio button, type in 3BB, then toggle the decimal button, and the number will convert). Alt+955 in this example. Of course you have to be in the appropriate font for this to work, and it doesn't seem to work in this reply window but I believe it would work in Chat. It works in wordpad but not notepad.

    If there is some symbol you use a *lot* it's worth writing down or memorizing the number.

    I'm no dummy, but that's all way too complicated for me! Much easier to just type out l-a-m-b-d-a. I will also say: thank god for latex!

  9. On a different site, SoftwareNerd wrote:

    At the core I understand Norsen to be saying: if you're convinced about TEW, do not misrepresent Objectivism by saying that TEW's"non-locality"-rejecting view of causality is based on the Objectivist view of causality.

    SN, you are making a good point on that other site, namely, that the TEW supporters do, in fact, explicitly base their support for TEW on Objectivism. But your claim here about what I am saying "at the core" isn't right. I mean, I certainly agree that anyone who is convinced (favorably) about TEW, shouldn't misrepresent Objectivism by saying that TEW is uniquely consistent with Objectivism metaphysics (which claim is simply preposterous). But *at the core* what I'm saying is this: if you're convinced (favorably) about TEW, you are an ignorant fool who has been swindled by a crackpot. And any perceived affiliation between such people (both the swindler and the swindlees) and Objectivism can only hurt Objectivism.

  10. Let's see...

    Thomas suggested that I'm calling TEW "aribtrary (less than wrong)". I never said that and don't think that. In terms strictly of its truth/falsity, TEW is false. What makes it worse than false is the evasive and dishonest character of its advocates' advocacy of it. But it is not arbitrary (in the technical Objectivist sense). It is not so much put forward in defiance of the need for evidence (and so ultimately meaningless), it is rather put forward in defiance of the fact that it contradicts known evidence and in massively negligent defiance of the proper methods for generating and attempting to validate scientific theories. (That's the "crackpot" point.)

    Thomas, in your other comments, I still detect a confused and invalid desire to ask, about any proposed new existent in physics, "but what's it made of?" or something to that effect. I think you could, with equal legitimacy, ask the same questions you are asking about (e.g.) "real waves being involved in QM" (and that you were asking about gravitational fields on the other thread), about atoms or electric/magnetic fields in the late 19th century, or about electrons around 1900, or about neutrinos and the host of other particles discovered since then, or about dark matter today, etc. For all of these I would ask you: what kind of answer are you looking for? The whole point of proposing new entities in theoretical physics is that they aren't made out of anything like the stuff known about previously -- else they wouldn't be "new". Now, maybe sometimes some future context of knowledge will allow an answer to that kind of question -- as, for example, it turns out atoms are made out of electrons, protons, and neutrons. But there is no basis for thinking that electric fields are "made of" some more elementary objects. So there is simply no answer to that kind of question. But I don't think further discussion of this is going to go anywhere useful, so take the last word if you want it on this.

    Regarding "the moon is made of green cheese" and the associated discussion of the relation of physics to philosophy, there is a false dichotomy being presented. It is not true that "physics has nothing to do with philosophy", but nor, as Thomas pointed out, is it true that physics is simply deduced from metaphysics. But there is a third alternative -- which is the truth -- namely, one *uses* (and hence *displays*) a certain epistemological approach in arriving at ideas in physics (just as in any other field). So if one claims to be an Objectivist, and/or is supported by self-proclaimed Objectivists, and/or is listed as a physics "expert" on websites (literally) under the banner of Ayn Rand, etc., reasonable people out in the world would be perfectly justified in assuming that the epistemological approach to ideas one displays are somehow expressive of Objectivism. And so if the "one" in question here is in fact a complete crackpot, including all of the aspects I listed in my book review, it reflects *very poorly* on Objectivism. This doesn't seem like a really tricky point to me.

    Thomas wrote that "that part of [my] thesis is overblown" -- meaning the part about my thinking TEW is an embarrassment to and danger to Objectivism. His grounds for this was a reference to the Maverick Philosopher, who thinks Objectivists are kooks on some grounds having nothing to do with scientific claims. I just don't get that argument at all. Yes, there are some dishonest or otherwise hopeless people who think Objectivists are kooks. But there are also lots of honest and sensible people (including, say, your average physics professor) who have no real opinion one way or the other about Objectivism. These are the people that matter, and they are the ones whose opinion may be *rationally* swayed *against taking Objectivism seriously* if they find it to be associated with something like TEW that they are in a position to recognize for the dishonest crackpot garbage that it is. Again, not a really tricky point.

  11. Grames, thanks, these are all very good questions/points.

    Didn't TEW at one time incorporate reverse waves from the detectors/polarizers to the photon source?

    That's the whole essence of the theory, so yes -- but not just "at one time". Still.

    Of course Aspect (setting the polarizers only after the photons are in flight) is not compatible with any reverse wave theory.

    That's right. Actually maybe it's worth amplifying for people who don't know the history. Aspect's experiment was in 1982. In the decade or two prior to that, there had been a number of tests of the correlations that are supposed to be restricted by Bell's "locality inequality". But all of these tests used static polarizers, and so (as everyone recognized all along) it would have been possible to account for the results in a locally causal way by positing some kind of influence propagating (at or slower than the speed of light) from the polarizer on one side, to the particle/polarizer/detector on the far side. That is, if the polarizers are just sitting there in place, then there is no real argument from relativity's prohibition on superluminal causation to the premise of Bell's theorem you describe below (namely, that the outcome on one side shouldn't depend on the setting, the orientation of the apparatus, on the other side).

    This maybe clarifies the way in which it is disingenuous for TEW supporters to say things like "well, there's just this one experiment that Little hasn't yet figured out how to account for". The truth is that this experiment -- and then the much cleaner and better version of the same thing that Weihs et al did in 1998 -- was done *precisely* to rule out the possibility of a broad class of theories of which TEW is one example. And the results of these experiments are pretty unambiguous.

    The general derivation of Bell's inequality (correlation <= 2) is from the statistical independence of two variables, the measurements A and B. Quantum mechanics predicts a specific correlation value, -2√2. The experiment measures -2√2. The conclusion must be made that the measurements A and B are not independent.

    That's right.

    One thing I don't follow is equation 10, where the presence of possible multiple factors lambda in computing both M and N doesn't prevent the claim that M and N incorporate a hypothesis of local causality. Sure M|a,λ is no function of b, but it is of λ whch also appears in N|b,λ. Is the presence of 'a' enough to make M independent from N? (I suppose it is but I wonder why).

    The lambda (not sure how you managed to produce the symbol here??!!) refers to some kind of "complete state description" for the pair of particles. Let me say that again in a different way because it's important: lambda provides a description of the *pair* of particles, jointly, i.e., the pair treated as a unit. Now, I'm not entirely sure I understand what's bothering you, so correct me if this is wrong, but I *think* your question is: doesn't this allow a certain subtle sort of non-locality and hence weaken the claim that all of this is being derived from the premise of local causality?

    If that's right, you're absolutely right. Bell's presentation here actually permits (say) the outcome on one side (M, or more precisely the probabilities for different possible outcomes M, since Bell is here not assuming determinism) to depend on the instantaneous state, not only of the particle that's getting measured there, but also, in principle, on the state of the distant particle. And there's indeed no locally causal way in which such dependence could be explained -- the distant particle being, after all, distant. So if, for example, you have a theory in which the states of the individual particles (say) changes randomly after they leave the source, such that the state of one particle would not necessarily allow you to infer with certainty the state of the other particle, you could sneak some nonlocality into the theory and it would *still* respect the correlation limit expressed in Bell's inequality.

    But let's be very clear about what that means. It means that any theory which *fails* to respect that limit, i.e., any theory which predicts violations of Bell's inequality, has to be *really* non-local. That is, this subtle weakening of the premise actually strengthens the overall argument.

    Of course, as you raise below, we can already at this stage of the argument assume determinism if we want, because we can already infer that separately, from local causality, using the EPR argument. So this point is really somewhat moot. I think Bell did it this way because the relevant state description *in orthodox quantum theory* is not "separable", i.e., you can't reduce it to "the one particle is in the state such-and-such, and the other particle is in the state so-and-so". Rather, it's irreducibly of the form: "both particles jointly are in the state such-and-such." That's admittedly weird and hard to understand. But, for Bell's purposes, everything is much clearer and better if you simply leave that aside and focus on the more radical sort of non-local causation that violation of his inequality entails. And plus, this way, there is an unambiguous (though not uncontroversial) argument that orthodox quantum theory itself already displays the problematic sort of non-local causation (in addition to the sort I think you are raising a question about here).

    I understand the argument that EPR inferred determinism from local causality (page 4). Can determinism still follow from non-local causality? (I would think yes.)

    No, definitely not. The argument was that, in the special case where the two experimenters measure along the same axis, it's an experimental fact that the outcomes on the two sides are always perfectly correlated. And, say EPR and also Bell, the *only* way to account for this correlation -- *if* you don't allow the possibility of nonlocal causation -- is that the outcomes were determined all along and somehow encoded into each particle separately at the source. But if you *do* allow the possibility of nonlocal causation, then you could have a model like this: neither particle is determined to produce either particular outcome for any of the possible measurements you could make on it -- but then one of the particles gets measured, is forced to "make an arbitrary, non-pre-determined "decision" about which outcome to produce, and (say) calls the other, distant, not-yet-measured particle on a little tiny faster-than-light cell phone to tell it which outcome it decided to produce. Then, should the other particle be measured along the same axis, it will "know" how to answer so as to guarantee the perfect correlations. The point is, such a model is explicitly nonlocal and explicitly non-deterministic. Yet it produces the right correlations for this special class of experiment. So clearly you're not going to be able to infer determinism from these correlations if you allow nonlocal causality. Make sense?

  12. I've just read the Standford article on Bohmian Mechanics and since we are basically comparing Bohm's pilot wave to Lewis Little's TEW ....

    I'll try to answer your questions, Thomas, but for the record: no, that isn't what we're talking about, if what you mean is that a positive assessment of Bohm's theory is somehow part of the argument for the

    worse-than-false status of TEW. You can know with absolutely certainty that TEW is wrong and that Lewis Little is a crackpot without knowing *anything* about Bohm's theory. The only relevance of Bohm's theory to this conclusion is that Little's book contains a number of very deceptive polemics against Bohm's theory, so understanding something of the truth on that point adds a little bit of evidence in support of the claim that he is, at best, negligently ignorant of what he's writing about.

    OK?

    Your main question about Bohm's theory seems to be: where do the waves come from? You are correct that there's not really any answer to this question in the theory. Probably the best way to think about what the theory says on this point is this: the waves have always been there, accompanying the particles. So, for example, a device that emits particles dosn't *produce* a new wave for that particle ex nihilo, nor is the wave "emitted" by the particle as it travels. Rather, that particles has always had some kind of accompanying wave, and what the particle emmitter does is to somehow reconfigure the structure of the wave.

    The main point, though, is that your question isn't a *necessary* one in the contemporary context of knowledge. It's just the same as your question about Newton's theory of gravity. There is no need whatever to answer this kind of question before believing in the theory. (I'm not saying anyone *should* necessarily believe in it, just that such belief can be fully justified without having any particular answer to the question of "where the waves came from originally".) A parallel here might be: you can rationally believe that the theory of evolution by natural selection is true, and even have certainty on that point, without having any answer to: "But how did life get started originally?" It's not that it's an invalid question, it's just not one that necessarily arises as part of the answer to: "By what mechanism did man and other species evolve into their current identities?" So maybe in 10 or 100 or 1000 years, once we figure out (say) exactly what's happening in the double slit experiment, then some future generation of theories will address something like your question in some way. Or maybe not. The point is just that, now, that kind of question is no kind of valid objection to the theory, nor even a proper basis for "concern" about it.

    You also said there's no equation in Bohm's theory for the "force" exerted on the particle by the wave. The equation you seek is right there in section 4 of the article ("the guidance equation"). This is an equation for how the *velocity* of the particle depends on the structure of the wave. This is the cleanest and most revealing way of defining the theory mathematically. But if, for some reason, you insist on couching the theory in Newtonian terms, you are free to take the time derivative of this equation (to get the *acceleration*) and then multiply by the particle's mass to get the literal *force* exerted on the particle by the wave. Turns out you can write it as minus the gradient of something, which is nice, because then that "something" can be interpreted as an extra, purely quantum contribution to the particle's potential energy field. This is how Bohm himself originally formulated the theory. (See section 5 of the article for more on the "quantum potential".)

  13. First, some quickies...

    Grames: good for you! It's probably my all-time favorite physics paper. I mean, even just the first sentence is completely brilliant and hilarious. I hope you enjoy it, and I would be delighted to help if there's anything in there you get stuck on, or want a different formulation of, or don't think is right, or whatever.

    AisA: There are lots of schematic pictures of this sort of experiment online. I just googled "EPR Bell experiment" and found a wikipedia page with a semi-acceptable (but highly schematic) diagram: see here. I'm sure if you spend just a minute and look at other hits, you'll find something better. You can also check out the actual paper by Gregor Weihs, et al, who did the infamous Innsbruck experiment. (By the way, nobody but people on one side or the other of the TEW debate calls the experiment that. Same with "double delayed choice.") The paper is too technical to follow all the details of unless you are trained in physics, but there's another good schematic diagram, and some pretty careful description of the real details.

    softwareNerd: thanks for clarifying the ground-rules about the content of the thread (viz., no meta-discussion and no off-topic discussion of other theories). Hopefully the following quick remarks won't violate the rules. (If they do, you have my blessing to just delete them.) A reader wrote me privately and made a good point: a lot of people here seem to misunderstand the concept of "ad hominem." This is properly understood as a logical fallacy, i.e., as a kind of argument that isn't valid because it substitutes or sneaks in a personal attack where a genuine premise should be. But what I said about "altonhare" was simply not in this category. And neither is anything I have said about Lewis Little. And neither, by the way, is a statement like "Kant was not only wrong, but evil, because..." The point is, it isn't the fallacy of ad hominem merely to criticize someone. If you say "he's wrong because he's a jerk" that's an ad hominem fallacy. But if you say "he's a jerk, because he tripped me and spit on me" that is just a regular old valid argument which has, as its *conclusion*, a statement about someone's character. Maybe that will be helpful to some people in trying to understand and assess all these claims that I'm attacking the person instead of discussing the physics, etc. Let me finally stress something that I probably should have clarified better earlier on. If TEW was merely a wrong theory, it of course wouldn't deserve the things I've said about it or its supporters. Nor would it be any kind of danger or embarrassment to Objectivism. But my whole thesis is that TEW is *worse* than "merely wrong". It is, for someone with the relevant background knowledge, *obviously* wrong, *obviously* unprofessional and unserious, and its supporters have repeatedly engaged in dishonesty and evasion. That's why I described the theory as "dishonest crackpot garbage" as opposed to, say, "false." I am saying all of this now just to further clarify why I introduced terms like "crackpot" and "dishonest" into the discussion from the very beginning (and thereby unwittingly brought about the flood of meta-discussion). It's because these things are an *essential part* of the conclusion I am arguing for -- TEW should be shunned, not because it is false, but because it is dishonest crackpot garbage. Hopefully that clarification isn't out of bounds.

    Now finally let me say something about this essay Olex linked to:

    The following is a great and simple explanation of a double slit experiment.

    http://speicher.com/tew1.html

    Actually I think this is, at best, highly misleading. I mean in particular the part around "figure 3" where Mr. Speicher tries to argue that there is strong evidence for the basic TEW "reverse waves" hypothesis in the fact that an interference pattern is still observed even if the detection screen is moved forward or backward. This is actually complete hogwash. Maybe it would be good to pause here and allow interested readers a minute to contemplate what massive tacit premise is smuggled into the argument.

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    Seriously, take a minute and think about it.

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    Got it yet?

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    If this were a class, I would actually wait in silence until you volunteered something. But, OK, fine, I'll just tell you.

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    Here's what I have in mind. The whole discussion just assumes that *particles move in straight lines* (except where they don't, e.g., at the slits). But if you drop that assumption, then there is *no grounds at all* for inferring, from the fact that the interference pattern is preserved when you move the screen, that the screen is somehow causally operative in determining the trajectories of the particles. See, for example, the figure about halfway down the page on this article about Bohm's theory. What's plotted are simply a bunch of representative trajectories for the 2-slit experiment, as predicted by Bohm's theory. Note that they aren't straight lines, and so (I think obviously, looking at the picture) you're going to get a nice interference pattern no matter where you put the screen. (According to Bohm's theory, a particle just makes a flash/spot wherever it in fact hits the screen.)

    Actually, the situation for this pro-TEW argument is even somewhat worse than merely that there's no evidence supporting the claim that the particles go in straight lines. There's I think a problematic inconsistency in the theory here. For, according to the theory itself, the particle trajectories *do bend* at the slits. That of course would be fine if there was, in the theory, some clear account of why that happens there and not elsewhere. And of course, if TEW were really a serious and clearly-formulated theory, there'd be no question here -- we'd just go look at the paper or book or whatever where the theory is presented and this kind of question would be addressed. But in fact this is the kind of thing that isn't actually addressed, which is why I say TEW isn't a serious and clearly-formulated theory. Anyway, my point is that it seems like there really is an inconsistency here for the theory -- what, after all, is a "slit"? It's a place where there is... nothing. I mean, if the idea was supposed to be that the trajectories bend at the location of some blob of physical stuff, that would be perfectly plausible, because the waves could scatter off of the stuff or whatever. But there's no blob of stuff at a slit. A slit is precisely where the blob of stuff isn't. That is, what's there at the slit (where according to TEW the waves all scatter and the trajectories all bend) is precisely the same as what's there at any other random location behind or in front of the slits -- namely nothing (meaning, you know, stray air molecules, or whatever electromagnetic fields and whatnot are present in the "vacuum", etc.). But if this nothing can so effectively scatter waves and hence bend trajectories at the slits, why can't it do it at other locations in front of or behind the slits?

    And if you follow that, you see why it's then inconsistent to have assumed at the beginning that (other than at the slits) the trajectories have to be straight lines. In fact, it's even a little worse than that, because if the waves can scatter off of the "nothing" that's (say) behind (from the point of view of the reverse waves, i.e., in front of vis a vis the motion of the particles) the slits, then the whole claim that the waves emitted by (say) a point right in the middle of the detector will interfere constructively at the particle source, totally falls apart. Because now there won't just be these two constructively interfering paths, there will be infinitely more possible routes from that point on the screen back to the source (e.g., paths made of two straight line segments, but with the "vertex" at some other point in front of or behind the slits, and then also paths made of 3, 4, 5, ... straight line paths) and the net effect will be no particular simple pattern of interference at all. The whole alleged "explanation" of the double slit experiment falls apart.

    Or maybe it doesn't fall apart. Who knows. The point is, there's just no way to know because the theory is just a half-baked idea rather than a definite and clearly-formulated proposal. This is the kind of question that, if posed to Little or some pseudo-knowledgeable proponent of TEW, would result in new and ad hoc additions to the theory, which would in turn raise further questions and risk further inconsistency. And since (as I think I indicated in an earlier post in response to something Thomas had said) questions *just like this* proliferate in all directions as soon as you try to figure out how/whether this theory actually works, it's just not worth pursuing any of them. Especially when the EPR-Bell stuff so clearly and unambiguously rules out the relativistic local causality that Little has defined as a fundamental pillar of the theory.

  14. Or, is it that this is not considered unsurprising, but is indeed considered yet to be explained. Perhaps one explanation that some suggest is that there is some other aspect about the photon that we don't know about, which causes it to act one way or the other (is this the so-called "hidden variable" idea?).

    That's definitely on the right track. Most physicists wouldn't really consider the issue of whether or not it's "surprising" to be scientifically meaningful. They'd say: quantum mechanics just predicts that, for plane polarized light incident on a polarizer at a certain orientation, there's a certain probability for it to pass and a certain probability for it to get absorbed. What more could one want?

    Of course, one can and should want more -- ultimately. But it's also valid to knowingly postpone questions about "what's really going on" or "how to visualize it" until some future date at which there will be some actual evidence on which to base answers to those questions. So, I'm not in favor of "shut up and calculate" as a philosophy or a mantra, the way many physicists seem to be, but it is sometimes the perfectly reasonable thing to do.

    I will also mention that in *classical* E&M, we don't have photons (i.e., individual "particles" of light) at all -- just electromagnetic waves. And what that theory says is that a polarized plane wave incident on a polarizer will be *partially* absorbed and *partially* reflected. (More precisely: the component that is parallel to the polarizer's axis will be transmitted, and the component that is perpindicular will be absorbed.) And in a sense this gives the same math that one has at the photon-level in the quantum theory of the same phenomenon: the quantum mechanical *probability* for a single photon to be absorbed, is identical to the *fraction* of the wave's intensity or energy that gets absorbed according to the classical theory. This correspondence between the numbers probably counts as some kind of rough way of "understanding" the QM formulas, and would be cited as such by most physicists. Of course, to really understand what's going on causally, you'd need a consistently causal version of quantum theory. But this is at least something.

    For what it's worth, I also find Mr. Speicher's "pencil" analogy to be more confusing than illuminating, for precisely the reason you bring up.

    The way I understand Bell's Theorem is that he's saying that no such unknown aspect can explain the experimental results. Even if we assume some relationship exists between the effect that the unknown aspect has on one photon of the pair and the effect it has on the other photon of a pair, we are still unable to explain the experimental outcomes.

    That's basically right. I think part of what you had in mind here (but didn't quite say explicitly) is that Bell's theorem is not in any way based on some particular proposed candidate "story" or "theory" about how it works, how it should be visualized, etc. Bell's theorem actually doesn't have any specifically physics-related premises at all, beyond the assumption of relativistic local causality -- which is just the assumption that, *however* this actually works down at the micro-level, the outcome of the experiment over here shouldn't depend on how the experimenter over there chooses to orient her polarizer, and vice versa.

    Which means you don't actually have to know "how to visualize" what happens when a photon passes or fails to pass a polarizer, in order to *completely* understand Bell's theorem.

    Does that help?

  15. It may well be that the field is comprised of something more fundamental, but we haven't discovered that yet.

    That's certainly true. For example, it turns out tables are composed of something more fundamental. Of course, that doesn't mean that tables don't exist or aren't physically real or can't function as agents in causal explanations.

    I don't understand what you are talking about with the equation involving "change in something". Sorry.

  16. Several quick points.

    First, I agree completely with Atlas51184's post above. I couldn't have said it better myself.

    Second, all of this meta-talk about who is being rude or guilty of flinging ad hominem or whatever, is really pointless. In regard to altonhare, he is obviously just what I said -- a troll and a crank. The former means that he posts the same meaningless blather and links to the same crackpot sites online, on practically every thread on this site, obviously hoping that someone will engage with him on it. It is perhaps telling that as of this writing, the "last action" in the 4 most-recently-active physics/math threads (leaving aside this one and the one with Thomas) was a post from altonhare. His posts consistently have zero to do with whatever they are allegedly in response to, which is why they tend to terminate threads, i.e., end discussion. Their content is a bunch of completely made-up physics nonsense. It's several steps below Lewis Little, for god's sake. He is, in summary, a troll and a crank. That is not an ad hominem, because I am not even attempting to be engaged in any kind of argument with him -- precisely the opposite in fact. Calling him those things is merely a statement of fact and an invitation to others to stop responding to his inane crap. It only encourages more of it. (By the way, I am *not* the first person here to identify him as a "troll" and I only looked around for about 5 seconds.)

    Third, I just want to say that when I volunteered to stick around this site and chat with people for a while about my book review, what I had in mind was primarily that people would be interested in asking some questions about physics -- e.g., making sure they understood the derivation of Bell's theorem I presented in the review. It is profoundly disappointing that so far there has not been even one single question of that type. Maybe it's that my writing is so eloquent and clear that it leaves no possible follow-up questions. But I seriously doubt that. In any case, I still welcome such questions, whether from people who are inclined to agree with me, or from those who think what I've said is wrong or unwarranted. But I have very little respect or tolerance for people who, for example, *don't read* the whole body of my essay, then accuse me of engaging in unscientific ad hominem, and don't take advantage of my offer to answer questions about or elaborate on or defend the *many* physics points I brought up (or alluded to in passing) in the review. Whatever anyone else will say, what this behavior *actually* proves of such people is that they are unserious about ideas, and hence extremely dangerous to this intellectual movement. (Perhaps it's worth mentioning here, as a foil, Dr. Binswanger -- who scrutinized my essay extremely carefully and asked me about a thousand detailed questions, and then about a thousand more follow-up questions, and so on for several rounds, especially about the math-heavy part. I can't speak for him, but my impression is that he recognizes that this is a very important issue, and insisted on investing the time required to achieve rational certainty in a first-handed way. And only *after* doing all this hard work, he endorsed my review on HBL. This is more or less the approach that I thought surely at least some people here -- including especially my critics -- would take, too.)

    Fourth, in regard to my alleged "personal attacks", the charge is frankly preposterous for exactly the reasons pointed out by Atlas51184. That Lewis Little is a dishonest crackpot is a conclusion, from massive amounts of data, some of which I went to great lengths to present and explain in the review (and in subsequent posts). If my book review had consisted *exclusively* of saying "This book sucks, don't buy it or read it, because the author is a dishonest crackpot" that would indeed be a personal attack and would be inappropriate and non-objective. That's not at all what I did, people. And I agree with Atlas that anybody who can't see that is themselves not being honest. (Oh my god, another personal attack!!) Everybody agrees that there is such a thing as a dishonest crackpot, right? I mean, such people are really out there. And if one of them claims to be an Objectivist and presents his ideas under an Objectivist banner, that is a really serious and dangerous threat to Objectivism that people who care about the philosophy should take very seriously. The idea that calling someone a dishonest crackpot, no matter how much evidence is presented to defend the assertion, is a "personal attack" and hence ipso facto out of bounds, is frankly just stupid. What matters is whether the assertion is true. What I see in the behavior of those who act offended by my "personal attacks" against Lewis Little, is an acute lack of concern with assessing the truth of my assertion.

    Finally, I have to say I wonder if maybe I shouldn't have taken more time to explain the whole decade-long history of TEW and its proponents behavior. If people don't know at least some details about the several failed attempts by Lewis Little to account for this same one experiment, and the way that he and his supporters acted during these episodes, maybe an important part of the case for dishonesty (as opposed to just erroneousness) is missing. I don't really think so, but I'll give it the benefit of the doubt. So here is just one example.

    Here is the announcement (can you hear the trumpets in the background?) that, after at least one failed and retracted attempt (I don't remember the exact sequence), Lewis Little had finally solved this problem and figured out how to explain the results of these experiments with TEW. (The subsequent message on that list, which there's no point linking to now, is from Lewis Little and contains a web link to the new explanation. Of course that link is no longer active.)

    Now here and here are two posts from just a few days later pointing out two (different!) fatal flaws in Little's paper. Here is Stephen Speicher's reply to the first criticism, which I already pointed to earlier as a rather obvious and self-contained example dishonesty. Here is Mr. Speicher's response to the mistake I had pointed out. (Way to address the physics and not the person, there, Mr. Speicher!)

    And now here's the really fun part. Just a few days later, Mr. Speicher comes out with this. Interesting, right? Well at the time I was certainly interested in understanding the nature of the "discrepancy" that had been discovered in Little's paper -- not to mention ever so slightly dubious about the claim that it had nothing to do with the two (different!) fatal flaws that Al Tino and I had pointed out. So I asked the various people involved to please explain. The response was that I was kicked off the list. The same exact thing happened to Al Tino.

    Now would anyone like to explain to me how the actions of Lewis Little and Stephen Speicher (and the ridiculous list moderator) here can be understood as honest? And this is only *one of many* such episodes that occured.

    And I actually don't even intend this as proof of the dishonesty I have been claiming (though it is). I just want to share this bit of history so everybody can understand the extent to which Lewis Little has been beating his head against this particular brick wall for roughly a decade. That is, it's not like, in the months or years leading up to the publication of his new book, he didn't realize that these EPR-Bell experiments might be a particularly important thing to straighten out, in order to establish the viability of his theory. The honest thing for him to have done would simply have been to say, in chapter 6 of his book, that even after many years of trying, he couldn't figure out how to understand these experiments from the point of view of TEW, but was still going to try to work on it. That would be really stupid, because it would show that he was still suffering from serious delusions in regard to Bell's theorem. But at least it would have been honest. What did he actually do, though? He wrote a deliberate smear-job against Bell and Bohm and pretty much anything else in sight that he thought might distract the reader's attention away from the fact that his theory cannot account for the results of these experiments and he knows it. *That* is the over-the-top, blatantly unscientific, years-in-the-making kind of dishonesty that, I submit, deserves *precisely* the kind of treatment I gave it in my review.

  17. Somewhere along the line in physics, a field meant the assignment of forces in a volume and came to mean the actual thing there. So, the question becomes: Can the term "field" be used in the same way of the term "electron" that is both a higher level concept (since it comes after conceptualizing regular visual matter) and an actual particle? I think that is what you are basically getting at. You want to say that, yes, "field" is a higher level concept, but that it also refers to an actual something there, like "electron". I'll have to think more about why I don't think this is so. I will definitely grant you that there are real forces at work and that one can mathematically compute the energy of those forces within a volume of space. I think so long as one knows there must be a real physical thing there to impart those forces, it may not matter if you call it "the activation of the aether" or if you call it "the field." It's just the way the term field came about that leads me to think that isn't the proper way to think about it.

    Were you thinking that "field" couldn't refer to something real because the concept is so *abstract*? I definitely don't think that's right. "Electron" is a good example to explain why. Or "atom". Or "DNA". Or "modem".

    So,let me ask you another related question along the same lines, do you think Einstein's "space-time" is a real physical thing or just a conceptualization of something real that is going on?

    There are a lot of subtle interpretive issues with GR, so that's hard to answer straight. And I don't have the same expertise in GR I have in some other subjects. So, that said, my somewhat tentative sense is that the metric tensor in GR should be interpreted basically as the gravitational field. That's not exactly the same thing as "space-time" but is rather the mathematical object which is usually taken (I think dubiously) to describe "space-time" directly. So I wouldn't say that "space-time" is a real physical thing, but I am saying that what people actually mean when they talk about GR as involving warping space-time, etc., is not nearly as wrong as it might look. The words ("curving space-time", etc.) are dubious, but what they're actually saying -- that matter distorts *something*, which something in turn affects the motion of matter -- is probably true. I just think it'd be less confusing and misleading to call that something the gravitational field.

    One thing I do have against fields is that it is conceived as being able to impart a force without itself changing. In other words, fields are not thought of as something that is active and thereby acting on the test particles. The physics is basically, there is a field and therefore a force on the test particle.

    That's just not true. Fields (both in E&M and gravity) genuinely *interact* with matter (charged particles or masses) -- the matter affects the fields, and the fields affect the matter.

    you are saying the field is the cause of those forces.

    Right.

  18. I think it really comes down to whether or not one considers the field to be a real physical thing or a conceptualization of forces that would act on a "point test particle" in a volume of space surrounding the source.

    Yes, OK, that's true. It all comes down to that. You think the field is merely a conceptualization of possible forces (that *would* act *if* a test particle were placed somewhere). But what argument do you have for this? Or rather, what argument do you have *against* the counter-claim, that the field is a real physical object? The E&M version of this question is a completely standard one in undergraduate E&M courses, so you probably encountered it once. The field is indeed first introduced as a "conceptualization of possible forces" but then you discover that you can write the energy of a certain configuration of charges as an integral over an energy density defined in terms of the field, you discover that certain basic laws like the conservation of momentum only make sense if you attribute a momentum density to the field, etc. In short, it emerges in short order that the field is a real dynamical player -- it's a real something that carries energy and momentum and acts and interacts with charged particles. It's not just a "bookkeeping device" for keeping track of pair-wise relational properties between the charged particles. And of course *all* of this has an exact parallel for gravitational theory. To summarize, there is a bunch of really powerful evidence that the field should be treated as a real physical object.

    Do you have some kind of rebuttal to or objection to this evidence? Or maybe you just never heard of it, and were taught that the field is merely this abstract bookkeeping device.

  19. Thomas, I'm starting a new thread for any subsequent discussion of your idea that something was or is missing from Newton's theory of gravitation. It's not germane to the TEW thread.

    In your first post on this (on that other TEW thread) you wrote:

    If I take an apple and drop it from my outstretched hand, the apple goes from being stationary to moving faster and faster. Insofar as Newton was talking about observables -- i.e. the apple and the earth -- there is nothing wrong with his equations (omitting relativity for the moment). However, there has to be something surrounding the apple that is active and imparting that activity to the apple such that the apple moves. In other words, to use David Harriman's terminology, there cannot be any disembodied force; and yet, Newton never gave an equation for that which is acting on the apple.

    That's not really true. Newton gave an equation for the force, and disembodied or not, that force is supposed to be a real thing that expresses the relevant "action" on the apple. Maybe what you're getting at, though, is that we should be able to give some account of what entity exerts that force on the apple (the force being, otherwise, "disembodied"). Of course, Newton has an answer there, too: the Earth exerts the force on the apple. But then there's maybe a further problem: how can the Earth, which is over there, exert a force on the apple, which is over here? That would imply a kind of nonlocality, which Newton (and others) found anathema. This is precisely where Newton said: "yeah, there's some underlying causal story that needs to be filled in here... I'm all in favor of that... but to assert any particular such causal story now would be empty, arbitrary speculation." That is, he rejected on principle the idea that you had to provide an underlying causal explanation for something, in order to have adequate grounds for asserting that something.

    So much, I say, for the idea that Newton made some kind of *mistake*. But if your point is only that, at some subsequent point in history, people should have engaged with this question, I would (on the one hand) agree with that -- but would (on the other hand) then wonder what you're upset about, since in point of fact people *did* engage with this question. The concept of a "field", which was introduced into the developing field of electricity/magnetism in the 19th century, is just what's needed here. The idea is just that there's a field occupying all of space, and the Earth somehow distorts the field surrounding it, and that distortion somehow or other propagates out *through the field* to the place where the apple is, and then it's the "distorted" field *at the location of the apple* that exerts (directly) a force on the apple. So there is no dubious nonlocality (of the action-at-a-distance sort -- we're not talking about the faster-than-light-influences sort here at all), and no "disembodied" forces. The *gravitational field* at the location of the apple is the physically real thing which exerts the force on the apple. And this whole ontological picture is supported and further precisified in General Relativity. What more could you possibly want?

    I also don't understand at all what connection you seem to think exists between the body which exerts the gravitational force on the apple (which body is, I claim, the gravitational field) and de Broglie waves. You seem to have in mind that these are or must be the same thing. I don't understand that at all. Same with your bringing in of "inertia." Why should there be any need for a special underlying mechanism for inertia at all? Why can't it just be a physically basic fact that massive objects, because of their mass, require an external force to accelerate them?

    Oh, let me also mention one sentence from your second post that left me very puzzled. You wrote: "there is something there, the activity of which, that accounts for all fields and even inertial mass." If I understand correctly, you are looking for an infinite regress. Let me explain. You seem to be saying: "There's a force on the apple, but what object exerts that force? You, Travis, say it's the gravitational field. But what object's activity accounts for the field? There must be something deeper that physicists have failed to identify." But why in the world should you insist a priori that there is some further underlying object, of which the gravitational field is merely an effect? What's wrong with just saying: the field exists, and acts a certain way, and part of that is its ability to exert forces on stuff. At *some* level you're going to just have to accept that something exists as "basic" and acts in a certain way. Otherwise you have an infinite regress -- even supposing I allow you to posit meta-energy-puffs (or whatever you think is the real object underlying and "accounting for" the gravitational field), then you will (or if you don't, I will, for the sake of this argument) just ask: but there's gotta be something else there, the activity of which accounts for the meta-energy-puffs. And so on.

  20. JeffT,

    You question my suggestion that people not talk up TEW with their friends or professors. I don't see what you think the problem is. If someone is known to be an Objectivist, and starts talking to his physics professor about this wonderful revolutionary new theory, and the physics professor subsequently looks into it and realizes it's crackpot garbage allegedly inspired by or based on Objectivism, that is one presumably intelligent and well-educated person who will never again take Objectivism seriously. Same goes for any friends who happen to be well-enough educated to subsequently form the correct judgment of the theory. This kind of thing (done by many people many times each) does real damage.

    You also suggest that I am asking people to ignore what they know of the character and intelligence of "highly respected" "prominent Objectivist supporters." Let's not beat around the bush here. There is only one person who possibly qualified under this description: Stephen Speicher. (Other vocal supporters, like Betsy Speicher and Prodos, do not have anything like the required context of knowledge to be proponents of TEW or any other physics theory.) I have no interest in getting into a discussion of the late Mr. Speicher's overall character, but I will point you -- as just one example of his behavior in support of TEW -- to the following post from the old TEWLIP archive

    TEWLIP message 876

    in which Mr. Speicher defends a (later retracted) TEW "explanation" of the Innsbruck experimental data -- which involved assigning to certain events *negative probabilities* -- by making up the most convoluted bit of gobbledygook obfuscation I've ever heard. This was, for whatever it is worth, the precise moment when I became absolutely convinced that his advocacy of TEW was dishonest (and I restrict this claim *only* to that advocacy, because outside of this realm I simply have no idea). But there is simply no other possible explanation for what he wrote in this post. Someone who has his technical background (and who is hence even able to *come up* with such a plausible-sounding pseudo-technical bit of total nonsense) simply cannot have produced such a thing honestly. (And this was not atypical of Mr. Speicher's defenses of TEW against rational criticisms.) I don't think you need much physics expertise to see and understand that. If you think or thought this sort of answer to a rather fatal objection to (that particular now-retracted version of) TEW was sound and convincing and scientifically respectable, it is because you got swindled. Sorry to be the bearer of bad news.

    Or perhaps you had some other "prominent Objectivist supporter" in mind?

  21. Thomas, I'm sorry, the "rant" was not directed at you. I thought that was clear, but I guess it wasn't. It was directed at people who support and proselytize for TEW without having the kind of knowledge required to justify their support.

    That said, the "rant" was... let's say... triggered by what you wrote. Let me explain why. You said you had a background in physics and had looked into Bohm's theory and found it problematic, so I asked you what you thought the problems were. Now, when I asked that, I didn't understand that your background in physics was a long time ago and that you maybe didn't remember much about Bohm's theory. I took what you said at face value, and inadvertantly backed you into a bit of a corner by doing so. For that I'm sorry. But there is some culpability here on both sides. Whatever the reasons or justification, your answer to my question about what you thought the problems with Bohm's theory were, amounted to you claiming something that isn't even true of Bohm's theory. It's a bit as if I had asked someone why they didn't like Objectivism and they said "because Rand advocated eating babies" or something. That's a little melodramatic, but I think legitimately parallel. The point is, if someone said that, you'd be entirely right to be a little annoyed and maybe censure them a little bit for having an avowedly anti-Rand stance on obviously insufficient grounds. (For example, nobody who had read even a single one of AR's books could honestly believe that she advocated that.) So that is a bit how I felt when you claimed to have some physics expertise and to have looked into Bohm's theory, but then, when asked, came out with "the particles couldn't keep up with the waves, so the theory can't be right." That is simply not even remotely true of the theory, which tells me you don't actually have the knowledge you would need to have an opinion pro or con on Bohm.

    That said, you strike me as a very nice, intelligent, and honest person. So let's just forget this and move on, OK?

    You brought up another interesting point that maybe would be good for a different thread so we don't get too distracted from TEW here:

    I've brought this up with Harry Binswanger a while back when I was on HBL, and I think Newton "made a mistake" in formulating gravity in that he didn't come up with an active agent giving rise to gravity; and others took that approach for electric and magnetic fields. It's like something was left out at the beginning, and now it is hitting physicists over the head that there is something there. But Harry cautioned me in calling it a mistake, because Newton didn't have the evidence we have today.

    I address just this issue about Newton in the opening section of my "Bell's concept of local causality" paper that was linked to before. Maybe you'd like to read that and then we could discuss it. From what you said here, I am inclined to think I'd agree with Harry that what you're criticizing Newton for not having done is (a) something he couldn't possibly have done given the context of knowledge available at the time and (:) something that is certainly not required as any part of the proof of what Newton *did* (I think properly) assert. But I'd like to discuss it further if you're interested.

  22. One thing about Bohm that is puzzling is the nature of the interaction of the wave and the particle. If the source sends out a wave and emits a particle, it is difficult for me to imagine how that works, since the particle will be moving at less than the speed of light whereas the wave (presumably) moves at the speed of light. So, I'm unsure how they stay in sync as the particle travels.

    In Bohmian Mechanics, the particle moves with a velocity that is basically the group velocity for the wave that's guiding it. (I say "basically" because that way of talking really only makes sense if the guiding wave has the structure of a wave packet, like a little lump, which is only a special case.) What that means is that the "waveform" and the particle move together. So there's no worry about the wave outrunning the particle or vice versa. Also, the waves do not just automatically propagate at the speed of light. Where did you get that idea?

    I also just want to say, in general, that this whole way of coming at these questions is rationalistic and superficial. I don't mean that as any criticism of *you*, Thomas, because I understand that it's been a long time since you've thought seriously about any of this, so you're just going by rusty memories, and I did kind of put you on the spot to say *something*. So, sorry for pushing you into a corner like that.

    But still, the idea that one can just sort of "contemplate" the "overall reasonableness" of these different theories (based on a kind of superficial understanding of what they say and how they work) and get anywhere useful that way, is really rationalistic. It amounts to the idea that you can ascertain (or at least approximate) the truth of a theory by looking at its internal consistency and how it squares with metaphysics and/or common sense. Which, granted, maybe you can do for certain really obvious cases of crazy/wrong theories. For example, anybody who learns about the Many Worlds Interpretation and doesn't feel a little queasy (and form some judgment like: this just sound a little too crazy and extravagent to be taken seriously) is probably off. But I don't think TEW, or Bohm, or (say) GRW is in that category at all, where you can just look at them roughly and "intuit" that they do or don't "make sense". All these theories say (or purport to say) that there's one world, there's some waves and also some other stuff, and there are some equations (or in the case of TEW, words) that are supposed to describe how those things act and interact, and they all claim to be able to correctly predict the outcomes of experiments. So there's really nothing in any of them that could possibly be vetoed by either metaphysics or common sense. And so if that's all you've got in your toolkit to assess them with, you're kind of stuck -- which is *fine*!!! It just means you shouldn't have an opinion one way or the other on these things, and so probably shouldn't be proselytizing in public for any side of any of them. [end rant]

  23. I recomend to others reading Travis' paper on Bells concept of local causality.

    http://arxiv.org/abs/0707.0401

    Thanks for the recommendation. That paper, though, was really a rough draft which on hindsight was too sprawling. I've sort of broken it in half. The half containing the polemic against Jarrett is forthcoming in Foundations of Physics -- an earlier (but still pretty tight) draft is freely available here

    Local Causality and Completeness: Bell vs. Jarrett

    That paper includes a much briefer, but still I think illuminating, discussion of Bell's concept of local causality. But I am working (slowly) on a new shorter paper which focuses on that specifically. For now, though, I'd probably recommend the "Bell vs. Jarrett" paper (perhaps even skipping the sections about Jarrett) as a first thing to read if you want to understand Bell's concept of local causality and its role in his theorem. Then maybe read the older sprawling draft that Plasmatic recommended only if you really want to pursue it further.

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