A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Ste on 22 Feb 2010 14:45 On 22 Feb, 01:12, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 21, 8:01 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > Newton, then, discovered that this is a special case of the > > > conservation of angular momentum, which is a much more general > > > principle--however, conservation of angular momentum MUST be able to > > > reproduce the elliptical orbits of planets, or else it is wrong. > > > Kepler's rules constrained Newton's theories. > > > > Special relativity then changed Newton's laws, a bit. The basic > > > principles, like F = dp/dt remained, but Special relativity says that > > > space and time must transform differently than they do in Newtonian > > > mechanics. However, Newtonian mechanics is still a special case of > > > special relativity--as the speed of an object approaches zero, the > > > laws begin to reproduce Newton's laws. > > > In other words "Newtonian mechanics are valid, as long as nothing is > > moving". Which somewhat defeats the purpose of mechanics, which is to > > describe movement, no? I think you're rewriting history Mark. > > No, you are completely misunderstanding this. It almost seems > deliberate. > > SR must have Newtonian mechanics as a limiting case. That is, as > speed->0 SR must approach Newtonian mechanics. If SR approaches > something OTHER than newtonian mechanics when speed goes to zero, then > it is wrong. > > But the equations of SR *DO* approach the equations of Newton when > speed goes to zero. This is not a tough concept. Ah perhaps I can agree this time, where you say any theory must *approach* the predictions of previous laws under some circumstances. But that's just what I said, which is that all previous laws have been approximations (and therefore mathematically incorrect).
From: mpalenik on 22 Feb 2010 14:49 On Feb 22, 2:45 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 22 Feb, 01:12, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > On Feb 21, 8:01 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > Newton, then, discovered that this is a special case of the > > > > conservation of angular momentum, which is a much more general > > > > principle--however, conservation of angular momentum MUST be able to > > > > reproduce the elliptical orbits of planets, or else it is wrong. > > > > Kepler's rules constrained Newton's theories. > > > > > Special relativity then changed Newton's laws, a bit. The basic > > > > principles, like F = dp/dt remained, but Special relativity says that > > > > space and time must transform differently than they do in Newtonian > > > > mechanics. However, Newtonian mechanics is still a special case of > > > > special relativity--as the speed of an object approaches zero, the > > > > laws begin to reproduce Newton's laws. > > > > In other words "Newtonian mechanics are valid, as long as nothing is > > > moving". Which somewhat defeats the purpose of mechanics, which is to > > > describe movement, no? I think you're rewriting history Mark. > > > No, you are completely misunderstanding this. It almost seems > > deliberate. > > > SR must have Newtonian mechanics as a limiting case. That is, as > > speed->0 SR must approach Newtonian mechanics. If SR approaches > > something OTHER than newtonian mechanics when speed goes to zero, then > > it is wrong. > > > But the equations of SR *DO* approach the equations of Newton when > > speed goes to zero. This is not a tough concept. > > Ah perhaps I can agree this time, where you say any theory must > *approach* the predictions of previous laws under some circumstances. > But that's just what I said, which is that all previous laws have been > approximations (and therefore mathematically incorrect).- Hide quoted text - > > - Show quoted text - If you take any equation from SR and set v = 0 or c = infinity (or if you want to be fancy, take a limit), you reproduce the same equations of motion that Newton had. If SR could not do this, the theory would be wrong. In this sense, Newton's laws constrain the behavior of any new laws that we want to develop to supplant them. This is the point I've been making. It's not a case of "the old laws were wrong, throw them out," it's "the old laws give us an idea of how any new laws must behave in a certain limit."
From: Peter Webb on 22 Feb 2010 17:22 Frankly no. But as I say, I would avoid drawing too many conclusions from what happens in the classroom - it is simply a fallacious appeal to both majority and authority. After all, you'd surely object if I replaced the classroom with the church, and pointed out the unanimity of opinion on the existence of God amongst the congregation. _____________________________ No, but if you were able to shove a priest inside a particle accelerator, accelerate him to 0.999c, slam him into some gold foil, and time his ascent to heaven to three significant figures of accuracy - then I might believe in God.
From: PD on 22 Feb 2010 17:31 On Feb 22, 12:35 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > Frankly no. But as I say, I would avoid drawing too many conclusions > from what happens in the classroom - it is simply a fallacious appeal > to both majority and authority. I gather you think of physics classes as being all passive absorption. You do know this is a laboratory class, where students are expected to apply principles to see if they actually work? > After all, you'd surely object if I > replaced the classroom with the church, and pointed out the unanimity > of opinion on the existence of God amongst the congregation. Nah. But if even one clergy member could show me how to calculate the measurable outcome of a set of circumstances I could set up in real life, based on God's presence and influence, and that outcome did in fact turn up when those circumstances prevailed, and this prediction was different than the prediction of other applicable theories, then this would indeed be scientific evidence for God. So far, this has yet to happen. PD
From: Ste on 23 Feb 2010 00:16
On 22 Feb, 04:07, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 21, 6:38 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > Hmmm. So there appears to be two models for what has happened in such > > > > > cases: > > > > > 1) the student who went through those classes had reason and good > > > > > sense *stripped* of them to the point where they would believe > > > > > nonsense, and this result is inherent to the process undergone. > > > > > 2) the student who went through those classes learned something new, > > > > > including how to test unambiguously for extra dimensions (regardless > > > > > whether it has been yet determined by test) and what the motivations > > > > > for even considering them might be, so that what seems like nonsense > > > > > to the novice no longer seems like nonsense. > > > > > I dare say there is a third. The student went into the class without > > > > having any "good sense" in the first place, and therefore they were > > > > willing to accept anything that they were told there. > > > > Thereby implying that those who have expertise in the field are those > > > who lacked good sense to begin with and whose common feature of > > > gullibility is the parameter for success in the field. Nice. > > > I have suggested that this is a third possibility. I also note you > > read this outside of the qualifying statement I made immediately after > > the above (now shown further below), the essence of which is to say > > that the hobble of a purely mathematical approach may be that the > > maths ends up totally at large, unconstrained by the requirements of > > (and lacking the further inspiration of) a qualitatively physical > > explanation. > > The "may be" could well be a concern of yours, but it does not appear > to be borne out by fact. As I've repeated to you several times, the > prevailing theories DO all have underlying physical conceptual > frameworks. > They are not all cogs-and-levers of the form that you would like to > see, but that does not mean that they are purely mathematical > exercises. > It's remarkable that you have this apparent false dichotomy of cogs- > and-levers and, failing that, purely mathematics. I haven't really argued such a dichotomy. What I have said is that things like "backwards causation" are just totally irreconcilable with any physical reality as I know it, and it was you who then characterised this as "cogs and levers" and small-minded. And as I've said, repeatedly, what you call my "cogs and levers" approach is far more flexible than your caricature would imply. > > > Conversely, you also imply that those who have good sense to begin > > > with, and who do not suffer from gullibility, are naturally OUT OF the > > > field. > > > I am suggesting that those in the field may be selected by factors > > that are not obvious, but which undermine their collective claims to > > credibility, reliability, and objectivity on the broader questions of > > their field of study. > > As you wish. Basically, you're saying that you don't believe anything > that group of people put forward, because you can convince yourself > that any such group of people self-select to be nonsense-generators > (especially since they disagree with you). This puts yourself in > admirable position of being impervious to becoming convinced that > you're wrong, at least at the hands of any representative of this > group of people. You're characterising my position as being far more hardline than it is. What I'm saying, at it's most simple, is that I'm not willing to simply take the word of "authority". Separate from that, I've also made it clear that I have certain axioms that are not in principle unquestionable or irrefutable, but which would require such an overwhelming amount of evidence to overturn that they are, in practice, probably irrefutable. > > Incidentally, I once heard a fictional story that a mathematician and > > a gangster are both witnessing a coin toss. The coin shows heads ten > > times in a row. They are asked to estimate the probability of the next > > result. The gangster says "almost certainly heads". The mathematician > > guesses the gangster's logic, laughs, and says "an equal probability > > of heads or tails - the past results do not influence the future > > probabilities". The gangster suggests "it does if the coin is > > weighted". And regardless of the true nature of the coin, both gave > > answers that were heavily contingent on unstated assumptions (most of > > which will have been wholly implicit and unexamined as far as the > > conscious mind is concerned), and both raised issues that the other > > will almost certainly not have considered before giving an answer. > > Precisely! And you will note that there is an experimental test to > check which of these two models, including the presumptions of each of > their models, is at work. Note that it is not possible to determine ON > THE FACE of it I'll forgive this atrocious pun. ;) > which of these two models is correct or even more > likely, even if you have a hunch or a personal preference for one. But > both the gangster and the mathematician have put forward models with a > testable prediction. In particular, if you tossed it another 100 > times, the two theories would have remarkably different predictions, > and the *coin itself* will tell you which of the two models is a > better description of it. That's not true. A further 100 tosses would not discern definitively between the two theories, for the outcome would still be technically consistent with either theory. > Notice how different this approach is from sitting back and trying to > decide whether mathematicians (or gangsters) are groups of people who > self-select themselves into delusions, and therefore their models are > not to be trusted. Why do that kind of nonsense, when you can simply > ask the coin to show its colors? Because in the real world it is not simply a case of flipping the coin an infinite number of times. Let's face it, we both submit to evidence - that cannot be the difference between us. > > > > Of course I'd rather avoid saying that these students have "no sense". > > > > I'm much more willing to believe that they are simply not concerned > > > > with a practical-mechanical explanation, possibly because beforehand > > > > they don't have any well-developed intuitions for it, and secondly > > > > it's vogue in science at the moment to emphasise purely mathematical > > > > explanations over practical-mechanical explanations. > > > > > > Now, how might one test which of these two claims is what has really > > > > > happened? > > > > > > Let me suggest one. If (1) were the case, then because of the inherent > > > > > flaw in the process, then it would have likely been observed up to > > > > > this point that there is a whole class of former students who have > > > > > come to believe some principle that is objectively falsifiable. It > > > > > would be falsifiable perhaps by the construction of a whole class of > > > > > devices whose design is based on that principle and which (because the > > > > > principle is false) obviously don't work in practice. Perhaps you can > > > > > point to some cases like that where devices with designs based on > > > > > relativity or quantum mechanics simply do not work because the > > > > > principles are wrong. Or is it your claim that all such devices happen > > > > > to work by accident, even though the design principles are wrong? > > > > > If you're suggesting that it's improbable that a theory could work not > > > > because its premises were correct, but because it simply promoted > > > > correct behaviours, then wonders why religion has fared so well. > > > > I don't know of any practical, artificially created devices that are > > > used in everyday life whose designs are based on religious principles. > > > Do you? > > > But the form of the question is designed to confirm your > > preconception. > > I don't think so. Perhaps if you gave an example from the most recent > century of physics. I'm not arguing that religious principles have been used directly to create "practical, artificial devices". What I did suggest was that a theory can work because it promotes correct behaviours, independent of the truth of its explicit premises. Incidentally, for a long time I never understood the role of "oath- helpers" in the context of the common law historically, until I realised the religious significance of the oath - that is, you were putting your eternal soul on the line if you didn't tell the truth. And even though the premises of religious beliefs are obviously ludicrous, in this case they served a social function of encouraging honesty amongst those who believed. And if a notoriously God-fearing member of the community was willing to put his own soul on the line to support the word of the witness, then that was compelling reason to accept the testimony of the witness. > > If we are to judge theories based on their tendency to bring about > > desirable outcomes (which I think is one of the unspoken assumptions > > in your question) then it does not seem to me that a theory's premises > > need to be factually correct; only that it produces the desired > > outcome. Which is what I said in the first place. > > Whether a theory's premises are factually correct IS DETERMINED by > whether it produces accurate predictions of measurements. That's how > science makes that determination in the first place. Not really. Once you factor in technological constraints, margins of error, empirical constants, domains of applicability, sheer complexity, implict knowledge, and probably innumerable other issues, it becomes very difficult to discern whether the explicit body of knowledge is true or whether it simply produces sufficiently correct behaviours without there being any truth to its explicit form. > If two theories make the same predictions in a given experiment, then > the two theories are mined to find the place where they make DIFFERENT > predictions, and that becomes the place where the measurement is made, > because that's where the discernment is to be obtained. And it is via > this channel that you determine which set of premises are correct. > There is no other way to reliably make that determination. We both agree that reality is the final arbiter, but I've already said that I think you fail to capture how science is really practiced. > > If we approach both science and religion from that direction, then it > > leads to some interesting questions and some interesting explanations. > > > > > In > > > > any event, I'm willing to accept Feynman's argument, basically that QM > > > > amounts to a workable mathematical model, and makes no claim to any > > > > truth more fundamental than that. > > > > This under-represents Feynman's position. A deeper examination of what > > > he wrote, other than what has been sound-bitten for your viewing > > > pleasure, shows that he actually is responsible for the underlying > > > physical explanation behind the math. > > > Well I'm not giving a comprehensive treatment of Feynman's position, > > and on some points I would strongly disagree with him. Indeed, I'm > > pretty sure that at one time or another he had said that anything > > beyond a mathematical model was superfluous to physics. > > I don't recall anything ever written by him that said that. Reference > please. If not available, then permit me to consider your statement to > be unreliable propaganda. I'm afraid I couldn't find anything definitive after spending quite a bit of time looking, so if you don't recognise this as Feynman's position then I'd probably rather move on to a different point. I did however stumble over this, which you may find interesting as I did: http://www.friesian.com/feynman.htm > > But one cannot > > criticise him in that he seemed fairly open about his axiomatic > > position and, from what I've read, did not seem to represent the > > mathematical models as being anything other than what they are. > > > > > > > > The point is, your argument boils down to "the only people I see > > > > > > > convinced of alternate dimensions are the people who believe in > > > > > > > alternate dimensions," but that's a circular argument. > > > > > > > It's not circular. It's a simple statement that there is, to a certain > > > > > > degree, a self-selection process, wherein the people who have a > > > > > > susceptibility to these sorts of arguments are precisely the ones who > > > > > > adopt and build on them. > > > > > > Or, to couch this in terms of the second option listed above, this > > > > > selection process happens to find those who are susceptible to > > > > > learning something new and which is in conflict with their incoming > > > > > presuppositions? > > > > > I really don't think everyone has particularly strong preconceptions > > > > (i.e. they'll believe anything), and nor do I think everyone has a > > > > taste for challenging authority. As I say, my argument is that the pre- > > > > existing interests, aptitudes, and psychology of students probably > > > > determines to a large extent what they're willing to accept as > > > > credible and coherent. > > > > > To identify a relatively small minority of people (that is, > > > > physicists), who have necessarily been weeded from a very large > > > > population, and then appeal to a further subset of those in order to > > > > somehow prove that additional dimensions are credible is just silly. > > > > Oh, come on. Scientific theories don't rise to the top because their > > > proponents are just predisposed to be gullible and are willing to > > > believe anything. > > > You know there's far more to it than that. Surely you've had enough > > discussions with me to know that I'm not making such a simplistic > > argument. > > > > Science doesn't judge truth on the basis of what > > > you're willing to believe. > > > Fundamentally, it does precisely that. > > No, sir. > I've discussed this at length with you, and your mathematician vs > gambler parable above points to where this falls apart. I don't know whether you misunderstood my meaning, but accepted scientific knowledge does fundamentally come down to people's willingness to believe and nothing else. As I've said, we both submit to the external world, but you don't seem to recognise the limitations of this. > > > Things aren't true in science just because > > > scientists are willing to believe them. This is the point of > > > experimental test -- to consult NATURE on what should be believed and > > > not believed. > > > But then we come back to "the theory deciding what you observe". > > As I've said, this does not happen, Einstein's bon mot > notwithstanding. You keep repeating this statement as though it were > an accepted maxim. It's not. I'm not repeating it as though it is accepted. I'm repeating it as it characterises my position so well, but I see no sign that you acknowledge that there is even a modicum of sense to what I'm saying, which is unfortunate. > > People tend to find a way of consulting the external world in a way > > that is consistent with their preconceptions. > > Not scientists. Haha. Bollocks! > This is certainly true for you, and you've both > confessed it and demonstrated it. Scientists try to break out of that > time and time and time again. It is undoubtedly true for me to a certain extent, although I generally consider myself to have intellectual integrity and a fair amount of self-awareness. As for "scientists trying to break out of it", I think this is just a ridiculous generalisation about the conduct of scientists, and in any event says nothing about whether they successfully break free (they don't, of course). I don't know whether you're just a bulldog of your profession Paul, in which case it's not going to do any good to break you down on these statements (because it's a waste of my time if I fail, and if I succeed it leaves you alienated), but in a lot of ways you seem to typify the very problem you say science needs to overcome: the problem of preconceptions and closed-mindedness. And unlike me, you appear not to acknowledge that preconceptions permeate and probably dominate science - indeed I dare say that the more important the question, the more the answer is permeated by preconceptions. > > > I understand your contention, that surely any experimental test should > > > be accountable by a theory which contains principles that ANYONE can > > > believe, not just those who are predisposed to be more open-minded. > > > I'm not necessarily saying this. What I am saying is that there is > > potentially a fallacy in appealing to the opinions of scientists. > > It's not a matter of opinion. It's a matter of what the product of the > scientific method is, which is designed to *remove* opinion. Granted, > this process doesn't work perfectly. It doesn't work at all in that respect. > But it does beg the question of whether the *method* is the one to be > pursued to determine the truth. You've said you're not sure you > believe it is, but you don't have a better way of proceeding. Because like I say Paul, I'm not here to sell anything. After hours of chiselling, conservatives always fall back on the question "is there any better way?", and of course the very method you're espousing may well be better if only its proponents actually acknowledged it's systematic deficits and failings. > > > However, historically this hasn't panned out, and you have yet to > > > provide a proof of principle. > > > But are we implicitly back to a test of "achieving a desirable > > outcome" again? Is it possible that people would reject the truth > > because it would lead to an undesirable outcome? > > Anything is possible. Is it likely? Here you have a guess. Not really. I think you'll find the psychological literature is awash with data that points to cognitive biases that, I suppose at a very broad level, all tend to have in common the theme of putting those beliefs which are desirable above those which are factual. > So summarizing briefly, you would like to propose that investigation > should be structured in such a way that experimental data should be > accountable by a model with principles that are believable by ANYBODY. That's not an accurate summary. > And yet at the same time, you say such an investigative structure > might possibly be rejected because it leads to an undesirable outcome. > Thus, you have no evidence that your investigative approach is even > possible, whether there is any historical precedent for it ever having > been pursued, or that it was rejected in the manner you fear. I can only assume that you've misunderstood, though I'm struggling to identify where. I'm not advocating any particular alternative investigative approach. I'm making a criticism of your characterisation of the existing approach. If you somehow think I've described an alternative approach, then you've wildly misunderstood what I've written and indeed what I intended to say. > > > > whereas for me I'm more likely to think of a pendulum or > > > > basically some sort of clock. And then, when one mentions "time > > > > slowing down", people who imagined the "t-axis" may be inclined to > > > > develop the view that time has "fundamentally" slowed down (because > > > > the mechanical details of how time is measured is not actually within > > > > the realm of their primary interests), whereas I'm more likely to say > > > > "well, what is to stop the clock slowing down without time itself > > > > slowing down?", or even "what if it just *appears to the eye* that the > > > > clock has slowed down?". > > > > And yet there are tests for those questions as well. > > > For example, let's suppose "What if there is something that is going > > > on that is slowing the clock down without time itself slowing down?" > > > (First of all, physicists don't say time itself slows down. This is a > > > comic-book statement that does not represent the conceptual picture > > > physicists have for this.) > > > You know Paul I will hear your arguments if you contend that you > > personally disagree with a particular statement or interpretation, but > > you can't simply claim that everything that you don't agree with > > amounts to a "comic book treatment of physics". I can't recall a > > single occasion where you've said "some physicists may hold that view, > > but I disagree and my view is...". > > If you were talking about any subject on which there is any > substantial controversy, then I'd be relating that. > However, on the stuff that you are talking about, and in particular > special relativity, there really isn't much controversy about what > special relativity actually says or means. > There is plenty of controversy about *other theories* which may > compete with special relativity, but not about what special relativity > says. I don't think there's much controversy about the mathematial form of SR, but there certainly seems to be a fair amount of conceptual vagueness. > There is also plenty of superficial claptrap available on the web that > inaccurately represents what special relativity says, and plenty of > popularizations that render the statements in sufficiently vague > language that misinterpretation is quite common, if not completely > assured. Yes, those darn comic books. > > Indeed, according to what you'd have me believe, respectable > > scientists seem to spend so much time writing "popularisations", > > "comic books", and "falsehoods to entice the reader", it makes you > > wonder how they have ever got around to doing real science, and indeed > > no wonder that the average person does not understand when they spend > > so much time consuming bullshit which I presume you justify on the > > basis that the man on the street "can't handle the truth" and even > > people otherwise interested to learn physics would find the truth > > incomprehensible and aversive if delivered from the outset in an > > unvarnished form. > > Oh, but you have it completely backwards. Scientists spend relatively > little time writing popularizations, comic-book presentations, and > enticements to the reader that risk reader confusion. However, that > seems to be the majority of what you've read. If instead you read some > of the materials that scientists actually spend most of their time > producing -- and I've recommended a small, entry-level sample of that > -- you'd find many of these problems averted. I cannot help that you > choose to read rotten materials, and that you have the temerity to say > that appears to be all that is available to you. I was of course being sarcastic Paul. The real issue is that your answer for virtually everything you don't agree with is that I must have got it from a comic book (or some other publication that it in some way not meant for serious scientific consumption) and that it totally misrepresents the views of "physicists" (who are always referred to as some sort of homogenous group, with the entirety of whom you are totally familiar). > > > This question would lead to the following > > > test. If something is happening to the clock, then surely varying the > > > operating principle of the clock or choosing clocks of vastly > > > different construction would produce a different time-slowing effect. > > > After all, vibration affects some clocks and not other clocks, for > > > example. So if a theory predicts a certain amount of rate change, and > > > that rate change is observed in 19 different varieties of clocks of > > > all different operational principles, then it seems unlikely that what > > > is going on is some effect that is altering all these different > > > mechanisms in EXACTLY THE SAME WAY. Or one can even do this more > > > succinctly. If I predict that a clock's rate will see a certain rate > > > effect, regardless of clock mechanism, and if I RANDOMLY select a > > > clock out of a pool of four dozen clocks of widely different > > > operational principles, then the chances of the prediction being > > > exactly right for that randomly selected clock is quite low. > > > But of course this presumes that there exist a variety of suitable > > clocks that measure time by methods that employ qualitatively > > different principles. > > And there are! Would you like a small list? > *Mechanical oscillators, such as spring-based mechanisms. > *Potential well oscillators, using any of a variety of conservative > forces. > *Particle populations with well-determined half-lives > *Atomic clocks > *AC circuits > *Digital oscillators > *Optical oscillators When we are at the level where the fundamental principles of the universe is in question, I think you underestimate the difficulty in finding a diverse set of clocks which are not all subject to the same fundamental principles. |