The Dimension of Time
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From: Dirk Van de moortel on 5 Jan 2010 12:18 PD <thedraperfamily(a)gmail.com> wrote in message 4fe06327-388d-4589-b508-f5c8d02b43e9(a)r24g2000yqd.googlegroups.com > On Jan 4, 5:22 pm, "Dirk Van de moortel" > <dirkvandemoor...(a)nospAm.hotmail.com> wrote: >> PD <thedraperfam...(a)gmail.com> wrote in message >> >> 53496da8-2831-45a3-9289-39230b80d...(a)j14g2000yqm.googlegroups.com >> >>> On Jan 1, 9:47 am, Ste <ste_ro...(a)hotmail.com> wrote: >>> [Snipping for length] >> >> [yes, snipping to save heat] >> >>> And this implies what about the physics? That it is wrong because you >>> can't make sense of it? >> >> PD, this is the best reply I have read on Usenet in years! >> >> Do you mind my entirely posting it (tomorrow) on >> http://users.telenet.be/vdmoortel/dirk/Physics/ImmortalGems.html >> under the header >> "How to make mince meat of an armchair philosopher?" >> >> MultiCheers and a happy productive 2010! >> >> Dirk Vdm > > Of course you may. I'm flattered. Done: http://users.telenet.be/vdmoortel/dirk/Physics/Gems/MinceMeat.html Thanks! Dirk Vdm
From: Ste on 5 Jan 2010 12:22 On 4 Jan, 21:39, PD <thedraperfam...(a)gmail.com> wrote: > On Jan 1, 9:47 am, Ste <ste_ro...(a)hotmail.com> wrote: > [Snipping for length] > > > > > > > I knew you'd say that. But the truth is that what I'm positing about a > > > > symmetry of fundamental forces *is* a scientific theory, in that it > > > > can theoretically be tested against the material world. > > > > Where is the experimental test that distinguishes this theory from the > > > currently held thinking? > > > More to the point, why is current thinking more legitimate than this > > theory, if by definition the observations are consistent with either > > theory? > > But this is the precisely the point I'm making. In science, competing > models are judged on the basis of where they make DIFFERENT > predictions of measurable phenomena, and then experiments are set up > to determine which of the two made the better prediction. I'm afraid that's nonsense. Observations regularly fail to tally with the predictions of theory. And also, often experiments do not have sufficient accuracy to discern whether a theory is correct. Unfortunately the reality is that once a theory is implicitly accepted, much less collective effort is put into refuting it and developing better alternatives. > Science really doesn't give a damn about two models that make > completely identical predictions about everything in their domain of > application. But my model does not make "identical" predictions. It makes far fewer predictions. For example my model rules out the notion that the past or future exist materially at all. The question is why do *scientists* choose one model over another (esp. a more complex and less intuitive model), where the current stock of observations are consistent with either? > There is no sensible basis (in science) for favoring one > model over the other in that event. There is in fact no such case in > history where there have been two models that have made identical > predictions and claimed a common domain of application. Indeed. > > > Well, first of all, I would say it at best does a swap of one exotic > > > prediction for another. For example, you claim that symmetry will only > > > be restored long after humans are dead and gone, and so the > > > experimental test of that appears to be inaccessible. This is not > > > exotic? > > > I would say it is not exotic in that it doesn't resort to anything but > > the fundamental mechanisms that we are already able to observe. > > That is, it is favored because it is familiar? Familiar in that it is conceptually quite simple and uses known physical mechanisms of action. > > The > > only way humans would be able to survive a full run of the whole > > system would be to exist outside of that system, but of course the > > real question then is why such an impossibly high burden of proof is > > being placed on my hypothesis, while the same burden is not placed on > > existing thinking. > > The same burden IS placed on existing thinking. Where do you think it > is not? It simply isn't PD, because as we've just established, you place the burden of proof on me to show that all processes in the universe will reiterate (an obviously impossible obligation), whereas you implicitly accept (even if you don't expressly commit yourself) that the universe will not reiterate. You also accept the classical model of time, even though there is no observable proof of the past existing, and even though your thermodynamic "proofs" of the concept are anything but proof. Clearly, classical time is accepted implicitly (having suffered no burden of proof), with the burden of proof being placed on any theory that challenges it. > > > Secondly, nature is no more exotic than what it really is. There is > > > nothing in current theories that should be taken as "difficult" to > > > swallow, as long as it matches what is seen in experiment or makes > > > predictions that can be tested in the foreseeable future. > > > Indeed there was nothing "difficult" about the geocentric model. > > Except, of course, the model itself. > > And the fact that it lacked *predictive* power. It only had > postdictive power. How so? It predicted accurately that all stars move in the sky in an apparently regular pattern. The fact that it didn't predict *where* each individual star would move, well, the heavens are controlled by God and are not deterministic, after all. > This is the difference between a theory and an > empirical fit. The heliocentric model had *predictive* power where the > geocentric model with epicycles did not. No it doesn't. We still have to determine empirically the orbits of planets and stars. The only difference is that it is actually *simpler*, in that it says all plantets are subject to a common force based on a few measurable properties (like mass and velocity), rather than explaining each unique orbit with florid mathematics and diverse forces (or God). > This is what an epicycle > *means* -- it is a postdictive FIT to additional data, so that the > model *changes* to accommodate the new data. The advantage of the > heliocentric model is that the model did not have to change with the > addition of data. I know. And yet you don't recognise this retrodictive process in modern physics, where credible theories have apparently accreted 20- odd inaccessible dimensions, movement backwards in time, effect preceding cause, etc. I mean honestly, what theory would not fit if the world's finest physicists and mathematicians were told they could introduce as many variables as necessary, as many constants as required, and the theory does not have to be deterministic and causes can follow effects in time, and the only test of this theory will be that it have some predictive power in aggregate (i.e. its predictions will be proven given an infinite number of iterations, and an infinite amount of time)? > > > I'm sorry, but your interpretation of time is not the relativist > > > interpretation of time. I've already mentioned some aspects of the > > > relativist interpretation (fast and future light cones, for example) > > > which you find hard to swallow. Your interpretation is your own and > > > needs to have a new label rather than appropriating one reserved for > > > something else. > > > Well I don't really want to get into a long argument simply about what > > to call my interpretation. But there is nothing about the light cone > > model that is time-relative. On the contrary, it implicitly requires > > the classical model of time in order to understand, and the classical > > model of time is not a relative model of time. > > No, it doesn't. I think you are confused about what relativity means > and says. You are under the impression somehow that relativity should > insist that past and future light cones should be symmetric ACCORDING > TO principles of relativity, when it does no such thing. No I wasn't saying that. Essentially what I'm saying is that the "light cone" implicitly reinforces the classical model of time. I personally see no value in the model. > > To reillustrate the difference, the classical model of time measures > > events by reference to their distance from a common past event, not by > > reference only to the time-separation between the two events being > > compared. The classical model requires an absolute benchmark (the > > birth of Jesus, for example), the relative model does not. > > I'm afraid you're mistaken. Would you like a decent reading reference > on introductory relativity so you can learn what relativity really > says, rather than continuing this string of misapprehensions? I *know* what relativity says. Can you hear me when I say I'm *not challenging* relativity? I'm challenging the non-relativistic baggage that apparently accompanies any current interpretation of relativity. > > The light cone model does not work without classical time (and the > > conversions required for different frames of reference). > > > Personally I would utilise a different model to describe what the > > light cone model attempts to describe. I would simply draw a sphere of > > radius r around some point in space, and the radius determines the > > time interval required for events at the central point to be observed > > at the periphery (or the other way around). > > This is what a light cone IS. I think you should start by reading up a > little on relativity first. I'm afraid that isn't what a light cone is, and you've obviously not understood the difference (or the significance of the difference) between what I described and the light cone model. > > That's a somewhat > > different model, but it illustrates the same principle, and unlike the > > light cone model, one can draw the whole "light-globe" model by > > reference to the 3 dimensions that everyone is familiar with. > > > Of course, I'm happy to discuss the implications of this with you, but > > I expect the discussion can be moved forward by you actually > > discussing it, not by telling me that I don't understand and that I > > need to learn more. > > This is the point where I politely let you know that a newsgroup is > not a place to get a general education about relativity or about > physics. But it is supposed to be a place of discussion. > It is well-suited to answering specific and tightly > constrained questions, or for discussing fine points, or for relaying > buzz about interesting news in the field. However, once it becomes > clear that a poster is just lacking in background, this no longer is > the forum for correcting that problem. At that point, what experienced > and informed posters here do (which included a fair number of > practicing physicists) is to recommend good reading resources for that > background material. If you don't actually want to discuss the subjects you're preaching about, then you should have just said. My prior experience of newsgroups is that they are places of discussion, not book clubs. I've come here with a few relatively simple questions, for example about the flow of time, and from what I've seen there is a dearth of information elsewhere - what information I have found suggests that it's a problem in physics. Obviously, I'm come here expecting that there will be people here familiar with the issue, and looking to discuss it. In the event, I've found a few abusive cranks and an inept "proof" by way of thermodynamic laws. Clearly, the theory that needs revision was my theory that there might actually be some interesting people here willing to have a frank discussion. Instead we've discussed almost everything *except* the subject on which I actually wanted some detailed discussion. > > Wormholes are paradoxical simply because they suggest movement in > > space can be achieved without a commensurate amount of acceleration > > (and therefore without the expected level of energy input). > > And what is paradoxical about that? A paradox is where there are two > statements made by a theory that are in direct conflict. > Are you under the impression that physics includes a statement that > motion in space MUST be achieved with a commensurate amount of > acceleration (and therefore without an expected level of energy > input)? That seems a fair hypothesis, given that we do not observe movement in space without acceleration. Of course, you can go further and conjecture that movement may be possible without acceleration, but without any pre-existing observation of it, such conjecture seems unfalsifiable. > Please be careful to distinguish "paradoxical" from "conflicts with my > own expectations about what should be true". Indeed. For physicists who have no expectations, except that nature be more complex than it first appears, nothing is ever going to conflict with expectation. > > Of course, > > again, no doubt the concept will be tempered in due course to point > > out that such a wormhole would require an equal or greater amount of > > energy than traditional acceleration (thus robbing the concept of all > > real meaning). > > Why would it rob the concept of all real meaning? Are you under the > impression that the MEANING of a wormhole is "travel for cheap and > easy"? Where other than comic books would you get that impression? Where else indeed. > > > And relativity does not admit classical time travel, and I don't know > > > where you got the idea it did. > > > I never said relativity did - on the contrary, I've been repeatedly > > being saying quite the opposite, as you can observe from my previous > > posts. > > Then you and relativity are not in disagreement on this point. I know that! > Time > travel into the past is not permitted by *current* physics either. > Therefore, lodging the possibility of time travel as a complaint > against current physics is simply a misplaced accusation. If travel into the past is not permitted by current physics, then why do people talk of time as though it is navigable, and as though we are actually physically moving through it? Why do they put the dimension of "time" on the standing as the dimensions of space? > > I have said that existing interpretations of time, that which I am now > > consistently referring to as "classical time", require a navigable > > dimension of time in the sense that "going backwards" in time means > > restoring the universe to a previous state (and, of necessity, > > observed change implies that time is moving forward). Whereas my > > relativistic time says that "going backwards" is what happens to the > > astronaut in the twins paradox, and "going forwards" is what happened > > to the homebody, even though by classical time both went forwards > > (because neither returned to a previous state). > > I'm not really interested in "your" relativistic time. Then clearly that is the problem here. > I'd rather > clear up your misapprehensions about what relativity says about > relativistic time. But I don't have any misapprehensions about what relativity says. You merely misapprehended my views, and while you were at it appear to have misapprehended thermodynamics, too. > > I'm sure you're sensible enough PD to see the radical differences > > between those models, and regardless of what you think personally I'm > > sure you'll accept that most physicists, when they think of time, > > still necessarily think of time in classical terms, where the past and > > future continue to exist in some material sense. > > ??? I have no idea what you mean by "continue to exist in some > material sense", nor do I have any idea where you got the notion that > most physicists think of it in that way. I got that idea from reading about physics, believe it or not. That's *why* I want to actually discuss these issues with people who purported to know something about the subject. > > > That's the nice thing about experimental evidence. It's usually pretty > > > unambiguous. > > > Surely you can't be serious? > > As an experimental physicist, I'm quite serious. Here's how it works. > In model A, circumstance set C are predicted to produce a measurable > outcome X in quantity QA. > In model B, circumstance set C are predicted to produce a measurable > outcome X in quantity QB, where QB is different than QA. > Then in experiment, the circumstance set C is set up, and outcome X is > measured with sufficient precision to discern whether the measurement > agrees with QA and disagrees with QB, or agrees with QB and disagrees > with QA. > > Then the measurement quite unambiguously distinguishes model A from > model B. > > This comparison can be extended to more than two models where they all > predict measurably different outcomes QA, QB, QC, and so on. > > In some cases, a given experiment is sufficient to rule out, say, > model A, but cannot discern models B and C, because QB and QC are too > close together for that measurement to distinguish them. In such a > case, then the models are reapplied this way: > > In model B, circumstance set D are predicted to produce a measurable > outcome Y in quantity QB'. > In model C, circumstance set D are predicted to produce a measurable > outcome Y in quantity QC', where QB' is different than QC'. > Then in another experiment, the circumstance set D is set up, and > outcome Y is measured with sufficient precision to discern whether the > measurement agrees with QB' and disagrees with QC', or agrees with QC' > and disagrees with QB'. > > In this fashion, the *body* of experimental evidence, including the > tests under circumstance sets C and D, determines which of the three > models survives. > > It's absolutely straightforward. I'm a little surprised you thought it > was more ambiguous than this. To forgive your ridiculously technical description of how theories are tested, we return to the real issue that was raised, namely, how is experimental evidence "unambiguous"? > > And anyway, as Einstein said, "it is the theory that > > determines what you can observe" - by which of course he did not mean > > the observation itself changes, only the interpretation of it. > > Einstein's comment is off the wall and often misinterpreted I think you'll find my interpretation of what he said (and meant) is correct, whether or not you agree with the notion being expressed. > to mean > something that just about every physicist would vociferously disagree > with. I think you should read more about Einstein, and yes I agree that just about every physicist would disagree with Einstein - they certainly did back then. > > > > And although I don't know what specific cosmological evidence you > > > > refer to, I have of course heard a number of conclusions drawn from > > > > what has been observed in the cosmos. I've heard for example that > > > > matter at the edge of the universe is moving outwards at more than the > > > > speed of light. > > > > Relative to us, yes. Is there a problem? > > > Yes, insofar as matter is not supposed to be able to accelerate beyond > > the speed of light. Or have I misunderstood, in that two objects > > accelerating in diametrically opposite directions at .6c will appear > > relative to each other to be accelerating at 1.2c? > > OK, this is where your thin background is showing through. > First of all, the statement that nothing can be observed to be > traveling at faster than c is a LOCAL statement or a statement that > applies in flat space only. If you'd like to have that misconception > cleared up, I might suggest an article for layfolk in Scientific > American from Feb 2005, which I'm sure you can find at the local > library.http://www.scientificamerican.com/article.cfm?id=misconceptions-about.... I'm afraid I don't have access to that publication. If you have full access to the article you mention then can you post the text (or email me with it) please. In any event I've realised my mistake - see below. > Secondly, yes, in a frame of reference two objects that are receding > from each other at 0.6c will have a *closing* velocity of 1.2c in that > frame. (Please don't confuse acceleration and velocity. That's a > freshman error.) I'm sure I hadn't confused that. Acceleration is a change in velocity. > However, that does NOT mean that in the reference > frame of one of those objects, the other object will have a relative > velocity of 1.2c. There is a careful and physical distinction between > closing velocity and relative velocity in physics, and moreover, > closing velocity is not a frame-independent quantity -- it changes > values when you change reference frames. I've just realised that it would be impossible to accelerate two objects to .6c in opposite directions from a central point - to do so would require more than an infinite amount of energy (because the total force between the objects would need to be 1.2c's worth of energy). > > > > I've heard that energy goes into black holes and never > > > > comes out. > > > > Aside from radiation, yes. Is there a problem? > > > Only insofar as the exception of radiation would disprove the > > hypothesis that nothing ever comes out. > > Not so. The theory of relativity doesn't say that nothing comes out. > Comic-book explications of relativity say so. But relativity fully > affords the prospect of radiation emerging. It's been calculated by > the theory, in fact. I know. The point I'm making is that the statement that "what goes in must come out in some way" is perfectly consistent with intuition, but then the black hole simply becomes a place of dense matter and high gravity. I take your point though that comic-book treatments have probably led to misconceptions, and that when physicists say "the laws of physics break down" what the public hears is "physical laws break down" and not "it turns out physicists do not know the physical laws after all". > > > Note that there are gravitational objects that are absorbing huge > > > amounts of energy and mass and do not shine, as seen in direct > > > observation. > > > Agreed. The question, then, is how does the energy come out again? And > > the answer is EMR. Matter goes in, EMR comes out. > > No, it does NOT. That's what "shine" means. You mean observed black holes do not shine presently, or that they never shine? > > Because of course whenever anyone implores science to adopt a > > conceptually simpler model with aspects that cannot be observed except > > in the fullness of time, the response comes back simply "our existing > > model is adequate for what we already observe". > > "Conceptually simpler" or "embraces nothing that I find confusing" is > not a value proposition in physics. I'm quite willing to embrace things that I find confusing. > It is being able to make *distinguishing* predictions of measurable > phenomena that are different than other theories that counts in > science. Sorry, but that's what it is. I agree, but that proves my point, that if two broader conceptual frameworks are competing to explain the same observations, then something *other* than the scientific method determines which framework is held to be correct. That's why I said the other day that science is really just religion, and is also why the prevailing ideology in society largely determines what theories scientists (and others) are willing to implicitly accept and work with. > > I hope you realise PD that the difference is not between "scientists" > > and "non-scientists", it's between scientists who insist on only > > adding to existing models, and scientists who insist on challenging > > existing models. > > And I've already told you how that challenge is mounted: by making > *distinguishing* predictions of *measurable* outcomes. But like I've already told you, that gives the incumbent framework an advantage. > > > > > Entropy is related to the > > > > > number of available microstates. The energy of a closed system can > > > > > remain completely constant and the entropy increase nonetheless. > > > > > I'm afraid I don't agree. > > > > Then I suggest you take a course in thermodynamics to learn what the > > > *definition* of entropy is. > > > Let me start with the OED definition then: "A thermodynamic quantity > > that represents numerically the extent to which a systems thermal > > energy is unavailable for conversion into mechanical work". > > > The first question is, "unavailable for conversion" by whom? > > I see. So the basic problem is that your exposure to what entropy is, > is limited to dictionary definitions and so you naturally have open > questions. I know what entropy is, but the OED definition is as good a place to start as any. > Has it occurred to you that open questions is not innate to > the subject matter but is instead a feature of your limited material? > > Unavailable for conversion means by ANY physical process, human- > involved or not. This includes processes in the sun, at galactic > centers, in plant cells, cosmic rays, whatever. Fair one. So I suppose we can test this hypothesis by asking for an example of some thing that is unconvertible from its final state by any physical process. That is, we'd expect to find somewhere a hard- core of material or energy that is utterly unavailable to any physical process or force. So, do you have such an example? > > > > Clearly there many fundamental phenomena > > > > that can only exist in discrete states. An electron, for example, > > > > apparently has a discrete level of charge. If you have a closed system > > > > in which fundamental forces never tire or wear out, and in which there > > > > is energy that can only take discrete forms, and in which states can > > > > only change at a finite speed, then entropy can't increase - you get > > > > an oscillation of states, or a rotation of states. > > > > I didn't say there weren't closed systems where entropy didn't stay > > > constant. > > > Of course you didn't, because that would have contradicted the 2nd > > law. > > > > What is true is that in closed systems, entropy doesn't DECREASE. > > > And what is also true is that in many closed systems, entropy DOES > > > increase. > > > That is false, because you have *never observed a closed system*. > > We've already discussed this. No we haven't discussed it. This is the only discussion we've had on the issue. > You have some misapprehensions about the > application of models. You brought up entropy as a proof of classical time. I'm simply putting to you the faults in that proof. > Consider Newton's first law, which describes the behavior of objects > that are under the influence of zero net force. By *your* measure, > this law would never be applicable and therefore would be a completely > empty statement. Scientists vigorously disagree. > The same goes for the laws of Mendelian genetics, which NEVER strictly > apply. Are those empty laws? Yes. A law that only applies vaguely does not prove anything about the underlying nature of the phenomenon. > > > > Like the kinetic balls toy - without friction, the mechanism would > > > > never tire, because gravity never tires, and the momentum of the balls > > > > would always be conserved. The only reason the mechanism does tire is > > > > because it is not a closed system (and in any event the toy is not > > > > designed to be in balance with all the fundamental forces of nature). > > > > That's not entirely correct. I don't know what you think is going on > > > in that system that causes it to wind down. > > > A number of things cause that system to wind down (i.e. lose > > momentum). Off the top of my head I would say mainly air resistance > > (i.e. friction) - although I don't discount sound, heat, plastic > > deformation, chemical change, etc. But I'm willing to be shocked, if > > you have news for me. > > The influence of air and losses to sound can be removed by putting > Newton's cradle in a vacuum. You will find that the balls still wind > down, though not as quickly. Indeed, as one would expect. > This tells you that the case with the air present is not a closed > system unless the air is included in the system. And then, of course, > the entropy of the system increases, though the momentum and energy of > the system does not. > > In the vacuum case, there are conversions of translational kinetic > energy into thermal, stochastic kinetic energy (which increases the > temperature of the balls). Again, energy and momentum are conserved, > while entropy increases. But what is your point? I described exactly these processes that would cause the toy to wind down. None of it proves that the entropy of the universe has increased when the toy winds down. > > > > Thinking scientifically I suppose the problem with testing this > > > > hypothesis is that a closed system is unmeasurable by those outside > > > > it, and incomprehensible to those within it. In this way, closed > > > > systems can theoretically exist, but are untestable. > > > > That's also wrong. > > > There are two ways this can be done. > > > One is that the measuring device be INCLUDED in the system, and the > > > entropy change of that device is included in the closed system sum. > > > But even that requires the measuring device to be loaded with > > information gleaned from outside the system itself. And then the > > system must be opened, first to add the measurement device, and then > > again to gather data from the measuring device. > > Yes, and those end effects can be accounted for. But did you account for the effects of setting the initial state? > Note that the > measuring device can be set to only record during the interval while > the boundary is not breached. I know. I think you're still failing to understand why you haven't proved classical time at all with observations of "closed" systems. > > > The other way is to prepare a state and then close the system, let a > > > process operate, and then open the system and measure its final state.. > > > This can be done in such a way that the end-effects can be accounted > > > for. > > > But then you didn't measure a closed system. You measured an open > > system - the system was open at the start when the initial state was > > set, at at the end when the measurement was taken. A "closed system" > > that is not closed for all time is not in fact a "closed system" at > > all. > > And that's nonsense. There is nothing in the definition (except your > own) that a closed system is closed for eternity. Of course there is. That is the definition of a closed system, that it does not interact with anything outside of it. And yet you seem to think that setting up an initial state, "closing" the system, and then reopening it a very short time later to inspect, somehow "proves" classical time. > > > Why is increasing entropy epicyclic again? > > > Increasing entropy isn't the epicycle. Increasing entropy is the false > > assumption. It is the false assumption that necessitates epicycles in > > the *whole body of theory*, in order that there can be functional > > movement around the false assumption. > > Increasing entropy between two states A and B is not an assumption. It > is a MEASURED QUANTITY. Entropy is MEASURABLE. I never said it wasn't measurable. The question is whether the entropy of the universe is always increasing. > What epicycles in the whole body of the theory? I see none. I'm talking to you about them. > > > I just said that the universe is > > > not the only closed system for the purposes of experimental test. > > > I see. This is clearly one point on which we disagree. I am not aware > > of any such experimental closed system. At the very least, this closed > > system would have to exclude the forces of gravity and > > electromagnetism (note I say "exclude", not "overcome" or > > "disregard"). > > Not so! See my comment about Newton's first law above first of all. > Secondly, your notion of closed system is not the same as what > physicists mean by the therm. Of course not. Because of course a "closed system means what physicists mean by it". We're really into the realm of Humpty Dumpty here. Why don't you just accept that, whatever you mean by a "closed system", the universe isn't such a thing, and therefore the laws of thermodynamics (which are derived from observations of "closed systems") do not apply to the question? > > Secondly it would have to have been closed, and remain > > closed, for all time. > > This again is NOT the meaning of "closed system" as used by > physicists. It is purely your own. Of course. Because you're a physicist. And that's not what you meant by it. > If you want to discuss the meaning of the 2nd law of thermodynamics, > which makes reference to closed systems, then you need to learn the > meaning of that term AS IT IS USED by physicists. I'll ask you then, what is a closed system? And we can discuss the definition. > > > What? Why? Continuousness does not imply isotropy. Anisotropy does not > > > imply discreteness. > > > I think you'll find it does. But if you have some examples where there > > is both continuous-variability and anisotropy, then perhaps we can > > discuss them. > > Of course! The electric field surrounding a charge dipole is > continuous. But it is anisotropic. > Believe me, this is just one example. So the level of charge in the field can be infinitely large, and nothing will ever happen that is liable to transform the charge into another form of energy (i.e. there is no limit to the level of charge that can be maintained for all time)? Or are we at cross-purposes here? > > It is non-deterministic, and it doesn't purport to explain why > > the underlying mechanism cannot be determined. > > OK, first off, I have to ask you WHY you think that any physical model > MUST be deterministic. That is, it is your belief that any model that > accurately describes nature MUST be deterministic at root, with the > implication that nature itself MUST be deterministic. WHY do you > believe that? It's not that nature must be deterministic, but that it is hard to see how you can do science without determinism. Science doesn't really go any further unless you believe there is an underlying physical mechanism to be discovered. And indeed, there is nothing about the world that leads us to believe that it is fundamentally probabilistic. Everything before now that has appeared probabilistic has merely been a complex system. > > > > > Whether you believe it or not is not really relevant. What matters is > > > > > whether there is any *evidence* that it is fundamentally reversible. > > > > > This is where observation plays a key role and what separates physics > > > > > from philosophy. > > > > > Science does have a philosophy you know. > > > > But it invokes things that philosophy does not, and this is the part > > > you ignore. > > > Such as? > > Experimental test! Just to clarify, are we talking about what might be termed the 'principles of science', or are we talking about "what scientists do"? > > > And you are the one that is complaining about nonintuitive ideas like > > > wormholes, etc. > > > No, I'm complaining about ideas like wormholes (or singularities, > > classical time, etc.) that *remain* counter-intuitive even after > > exposure to the concept. > > I'm sorry, but there's nothing counterintuitive about wormholes or > singularities or classical time. Just because YOU have difficulty > being comfortable with the concepts doesn't mean that experience is > shared. A little humility, please. I'm not saying everyone has difficulty with them. All I'm saying is that those who do not have difficulty with them do not impose on themselves the rigor of reality. And no doubt, you surely need a creative element in society. Unfortunately there seems to be too much of it in science at the moment. > > > Please do not tell scientists how science should be done. Science is > > > DEFINED by the activity of scientists. > > > That's strange, I was led to believe earlier that you thought the > > activity of scientists was defined by science, not the other way > > around. > > No, I didn't say that. No, you didn't. That's why I said "led to believe". > > If science is defined merely as "what scientists do", then > > that is a bulletproof rejoinder to anyone who points out that what > > scientists are regularly doing is not at all in accordance with the > > commonly-apprehended principles of science. > > Then perhaps the "commonly-apprehended principles of science" are > misapprehensions, eh? Perhaps. I know a lot of law, and concepts like "reasonable" notoriously mean quite different things to lawyers than they do to the man on the street. Of course, I might be forgiven for assuming that when you appealed to the "principles of science", you meant you were appealing to some objective principles which could be compared to what scientists actually do. > If you want to know what science is, ask a scientist. If this > conflicts with your common apprehensions, then consider those > corrected. Of course, that presupposes that scientists know explicitly what they are doing, and are both able and willing to communicate it. > > > No, I'm sorry. The onus is on the person who presents a new model to > > > use that model to cite predictions that distinguish it from other > > > models. That is how science operates, and with good reason. > > > But how does that work when the new model makes *fewer* unverified > > predictions in some respect than the existing model? > > It doesn't make FEWER. It just puts some of those predictions out past > our accessibility. That makes it LESS useful. Not really. If a theory predicts that some events will only happen once humans have been and gone, then it's hard to see how the existence of such predictions could make a theory less "useful" at the present time in terms of predictive power. > > > > The question is whether *any* coherent theory requires it. I haven't > > > > heard any explanation yet for why the curvature of spacetime is > > > > distinguishable from forces acting acting on matter in the classical > > > > way in Euclidean space. > > > > Because they make different predictions of observable phenomena! You > > > aren't aware of these? > > > Indeed I'm not aware of any observable phenomena that cannot be > > trivially described in 3 dimensions. Even the effects of SR can be > > readily understood in 3 dimensions. Of course I'm willing to be > > corrected. > > Wait a second. Let me see if I understand you. You are saying, "My > present understanding of nature requires only three dimensions. If > nature exhibits itself to require an understanding of more than three > dimensions, then I'm not interested in such a model. That is, nature > must conform to MY current parameters of understanding, and I will not > accept any model of nature that does not accomplish that." Indeed, any model must conform to the requirement of understandability, and secondly any model of the real world must conform to the requirement of actually describing the real world. And you have to ask yourself whether a theory that rests on multiple, un- navigable dimensions, is not losing touch with mechanisms of action in the real world. > > > Well, as it turns out, you may be interested in quantum eraser > > > experiments. You can google that. > > > I've studied it again now scrupulously and I don't find anything > > shocking about it (even though the last page I read -http://www.bottomlayer.com/bottom/kim-scully/kim-scully-web.htm-said > > as a layman I ought to be). > > > Surely the outcome of the QE experiment is easily understandable if > > you conceive of there being a sort of EM field (i.e. a potential > > force, that "charges" space) which is distinct from the photon (i.e. > > an energy packet causing observable change of state) itself? I know > > that sounds like going back to the luminiferous aether, but it's > > surely more physically credible that "action at a distance" or "a > > particle in two places at once". > > When you can come up with a model that can *quantitatively* predict > those results like quantum mechanics can, rather than vaguely waving > your hands and saying "Surely something simpler can be made to > work..." There is no need to sell one's soul to the devil for a predictive theory! Clearly, the maths of quantum mechanics works to some degree. The question is whether the premise that it rests upon, of the "photon" being a particle of some sort, is correct, and clearly the QEEx ought to prove to any sane person that the premise isn't correct.
From: PD on 5 Jan 2010 16:14
On Jan 5, 11:22 am, Ste <ste_ro...(a)hotmail.com> wrote: > On 4 Jan, 21:39, PD <thedraperfam...(a)gmail.com> wrote: [Snipping a great deal. Rather than respond to everything I'd like to in this post, I will try to stick to areas where I will not repeat myself.] > > > But this is the precisely the point I'm making. In science, competing > > models are judged on the basis of where they make DIFFERENT > > predictions of measurable phenomena, and then experiments are set up > > to determine which of the two made the better prediction. > > I'm afraid that's nonsense. Observations regularly fail to tally with > the predictions of theory. And also, often experiments do not have > sufficient accuracy to discern whether a theory is correct. > Unfortunately the reality is that once a theory is implicitly > accepted, much less collective effort is put into refuting it and > developing better alternatives. I *completely* disagree. As to your first note, when this happens, it is a flag that there is a potential problem with a theory. That's what "falsification" means. On your second point, what is necessary in a well-designed experiment is that the measurement is sufficiently precise to force a choice between two theories with different predictions. If the experiment is not precise enough to do that, it is a failed experiment. Finally, the reason for implicitly accepting a theory is that other competitive theories have been ruled out by those distinguishing measurements. If a new competing theory emerges that is not ruled out, then the place where the new and incumbent theories disagree on predicted measurable quantities is rooted out, and this becomes the focus of new experimental tests. Keep in mind that my background is in experimental physics. > > > Science really doesn't give a damn about two models that make > > completely identical predictions about everything in their domain of > > application. > > But my model does not make "identical" predictions. It makes far fewer > predictions. For example my model rules out the notion that the past > or future exist materially at all. This is not a prediction of a *measurable outcome*. Please reread what I wrote about how two models are compared. What is the *measurable* quantity that is different because "past or future [don't] exist materially at all"? Theories are not judged by their *conceptual* distinctions. They are judged by the differences in predictions of *measurable* quantities. > > The question is why do *scientists* choose one model over another > (esp. a more complex and less intuitive model), where the current > stock of observations are consistent with either? They don't. For example, general relativity appeared (at first) to be less intuitive and more complex than Newtonian gravity. But Newtonian gravity made a prediction about the amount precession of the perihelion of Mercury, and general relativity made a *different* prediction about the same quantity. Measurement of the actual precession quantity to sufficient precision showed that general relativity got it right and Newtonian gravity got it wrong. > > > > I would say it is not exotic in that it doesn't resort to anything but > > > the fundamental mechanisms that we are already able to observe. > > > That is, it is favored because it is familiar? > > Familiar in that it is conceptually quite simple and uses known > physical mechanisms of action. And this is not a figure of merit in scientific theories, nor should it be. > > > > The > > > only way humans would be able to survive a full run of the whole > > > system would be to exist outside of that system, but of course the > > > real question then is why such an impossibly high burden of proof is > > > being placed on my hypothesis, while the same burden is not placed on > > > existing thinking. > > > The same burden IS placed on existing thinking. Where do you think it > > is not? > > It simply isn't PD, because as we've just established, you place the > burden of proof on me to show that all processes in the universe will > reiterate (an obviously impossible obligation), whereas you implicitly > accept (even if you don't expressly commit yourself) that the universe > will not reiterate. No, you are trying to ask for a comparison of predictions of measurements that are not accessible to us. What I am telling you is that the burden with existing thinking is prediction of *accessible* measurements. This is the domain where testing must happen and does happen. Any theory that produces no predictions relevant to measurements accessible in the foreseeable future is USELESS. > > > > Indeed there was nothing "difficult" about the geocentric model. > > > Except, of course, the model itself. > > > And the fact that it lacked *predictive* power. It only had > > postdictive power. > > How so? It predicted accurately that all stars move in the sky in an > apparently regular pattern. The fact that it didn't predict *where* > each individual star would move, well, the heavens are controlled by > God and are not deterministic, after all. And that is PRECISELY the point. > > > This is the difference between a theory and an > > empirical fit. The heliocentric model had *predictive* power where the > > geocentric model with epicycles did not. > > No it doesn't. We still have to determine empirically the orbits of > planets and stars. The only difference is that it is actually > *simpler*, in that it says all plantets are subject to a common force > based on a few measurable properties (like mass and velocity), rather > than explaining each unique orbit with florid mathematics and diverse > forces (or God). This is NOT the case. The heliocentric model demonstrated that it could *predict* the distance of the planets from the observed orbital periods or vice versa, which is something the empirically fit geocentric model could never do. Furthermore, by observing the perturbations of the orbits on the observed planets, the very *existence* of a new planet was predicted -- the model predicted precisely where Neptune could be found, and when they looked, there it was. Thus, there is FAR more to it than simplicity of concept and elegance of the math. It is the *predictive* power that marked the difference. > > > This is what an epicycle > > *means* -- it is a postdictive FIT to additional data, so that the > > model *changes* to accommodate the new data. The advantage of the > > heliocentric model is that the model did not have to change with the > > addition of data. > > I know. And yet you don't recognise this retrodictive process in > modern physics, where credible theories have apparently accreted 20- > odd inaccessible dimensions, movement backwards in time, effect > preceding cause, etc. Those are not epicycles. Those are scrapping old and starting afresh. These are not layers on top of classical physics. It is NOT the addition of new mechanisms on top of old ones. If you had a little more background and understood what these things really are, you might understand that better. > > > I'm afraid you're mistaken. Would you like a decent reading reference > > on introductory relativity so you can learn what relativity really > > says, rather than continuing this string of misapprehensions? > > I *know* what relativity says. Can you hear me when I say I'm *not > challenging* relativity? I'm challenging the non-relativistic baggage > that apparently accompanies any current interpretation of relativity. Then you don't understand relativity. The "baggage" that you think is not essential to relativity IS essential to relativity and what you think is essential to relativity does not constitute what relativity is. You have a very superficial understanding of what the word "relativity" means. In order to demonstrate that, let me just ask you what you think the underlying principles of special relativity and general relativity are. > > > > Of course, I'm happy to discuss the implications of this with you, but > > > I expect the discussion can be moved forward by you actually > > > discussing it, not by telling me that I don't understand and that I > > > need to learn more. > > > This is the point where I politely let you know that a newsgroup is > > not a place to get a general education about relativity or about > > physics. > > But it is supposed to be a place of discussion. > > > It is well-suited to answering specific and tightly > > constrained questions, or for discussing fine points, or for relaying > > buzz about interesting news in the field. However, once it becomes > > clear that a poster is just lacking in background, this no longer is > > the forum for correcting that problem. At that point, what experienced > > and informed posters here do (which included a fair number of > > practicing physicists) is to recommend good reading resources for that > > background material. > > If you don't actually want to discuss the subjects you're preaching > about, then you should have just said. My prior experience of > newsgroups is that they are places of discussion, not book clubs. It is an area of discussion where the participants are expected to have at least a modicum of background in the basics. When it is discovered that this is not the case, then a discussion forum does not become an avenue for education in the basics. This is NOT a good venue for that. You do not have a decent understanding of even the basics of relativity, and "discussion" will not provide that to you. > > > > Wormholes are paradoxical simply because they suggest movement in > > > space can be achieved without a commensurate amount of acceleration > > > (and therefore without the expected level of energy input). > > > And what is paradoxical about that? A paradox is where there are two > > statements made by a theory that are in direct conflict. > > Are you under the impression that physics includes a statement that > > motion in space MUST be achieved with a commensurate amount of > > acceleration (and therefore without an expected level of energy > > input)? > > That seems a fair hypothesis, given that we do not observe movement in > space without acceleration. Then this is not a paradox. It is a conflict of a statement in relativity against what you consider to be a fair hypothesis -- that is, it is counter to your expectations. Conflict with common expectations does NOT constitute a paradox. Relativity DOES demand that some preconceived notions have to be let go of. You are of the mind, "But I don't want to." This does not make relativity paradoxical. It only means that it conflicts with concepts that you cling to. > > > Please be careful to distinguish "paradoxical" from "conflicts with my > > own expectations about what should be true". > > Indeed. For physicists who have no expectations, except that nature be > more complex than it first appears, nothing is ever going to conflict > with expectation. Counter to intuition is NOT the same thing as "more complex". Relativity is a *simplified* picture compared to classical physics. People frequently mistake the clash with intuition as necessarily implying an increase in complexity. > > If travel into the past is not permitted by current physics, then why > do people talk of time as though it is navigable, and as though we are > actually physically moving through it? Why do they put the dimension > of "time" on the standing as the dimensions of space? They DON'T. A worldline does not MOVE. We do not have the freedom to change our rate of time lapsing, nor can we choose our location in time. You do not have a good understanding of what relativity says on this point, nor for that matter classical physics. > > > ??? I have no idea what you mean by "continue to exist in some > > material sense", nor do I have any idea where you got the notion that > > most physicists think of it in that way. > > I got that idea from reading about physics, believe it or not. That's > *why* I want to actually discuss these issues with people who > purported to know something about the subject. Cite the reference, please. > > > > > That's the nice thing about experimental evidence. It's usually pretty > > > > unambiguous. > > > > Surely you can't be serious? > > > As an experimental physicist, I'm quite serious. Here's how it works. > > In model A, circumstance set C are predicted to produce a measurable > > outcome X in quantity QA. > > In model B, circumstance set C are predicted to produce a measurable > > outcome X in quantity QB, where QB is different than QA. > > Then in experiment, the circumstance set C is set up, and outcome X is > > measured with sufficient precision to discern whether the measurement > > agrees with QA and disagrees with QB, or agrees with QB and disagrees > > with QA. > > > Then the measurement quite unambiguously distinguishes model A from > > model B. > > > This comparison can be extended to more than two models where they all > > predict measurably different outcomes QA, QB, QC, and so on. > > > In some cases, a given experiment is sufficient to rule out, say, > > model A, but cannot discern models B and C, because QB and QC are too > > close together for that measurement to distinguish them. In such a > > case, then the models are reapplied this way: > > > In model B, circumstance set D are predicted to produce a measurable > > outcome Y in quantity QB'. > > In model C, circumstance set D are predicted to produce a measurable > > outcome Y in quantity QC', where QB' is different than QC'. > > Then in another experiment, the circumstance set D is set up, and > > outcome Y is measured with sufficient precision to discern whether the > > measurement agrees with QB' and disagrees with QC', or agrees with QC' > > and disagrees with QB'. > > > In this fashion, the *body* of experimental evidence, including the > > tests under circumstance sets C and D, determines which of the three > > models survives. > > > It's absolutely straightforward. I'm a little surprised you thought it > > was more ambiguous than this. > > To forgive your ridiculously technical description of how theories are > tested, we return to the real issue that was raised, namely, how is > experimental evidence "unambiguous"? Is it not clear from the above? Did you find the above confusing? What is technical about it? Please reread the above with care. It is essential to how science works. If you do not understand this part, then you will not understand how science operates. > > > OK, this is where your thin background is showing through. > > First of all, the statement that nothing can be observed to be > > traveling at faster than c is a LOCAL statement or a statement that > > applies in flat space only. If you'd like to have that misconception > > cleared up, I might suggest an article for layfolk in Scientific > > American from Feb 2005, which I'm sure you can find at the local > > library.http://www.scientificamerican.com/article.cfm?id=misconceptions-about.... > > I'm afraid I don't have access to that publication. If you have full > access to the article you mention then can you post the text (or email > me with it) please. In any event I've realised my mistake - see below. I do, but that would be a copyright violation. You do have access to the article, via the link above. You may purchase access to that one article only. People who work in the field and hope to contribute routinely pay for access to literature in the field. I don't know why you think you should be excused from this. > > > Secondly, yes, in a frame of reference two objects that are receding > > from each other at 0.6c will have a *closing* velocity of 1.2c in that > > frame. (Please don't confuse acceleration and velocity. That's a > > freshman error.) > > I'm sure I hadn't confused that. Acceleration is a change in velocity. Rate of change in velocity. A change in velocity has the same units as velocity; acceleration does not. You can see for yourself where you made the error in your own words. > > > However, that does NOT mean that in the reference > > frame of one of those objects, the other object will have a relative > > velocity of 1.2c. There is a careful and physical distinction between > > closing velocity and relative velocity in physics, and moreover, > > closing velocity is not a frame-independent quantity -- it changes > > values when you change reference frames. > > I've just realised that it would be impossible to accelerate two > objects to .6c in opposite directions from a central point - to do so > would require more than an infinite amount of energy (because the > total force between the objects would need to be 1.2c's worth of > energy). No, it would not. It would require 2 times the energy to accelerate an object to 0.6c, which is certainly finite. I'm sorry, but it's things like this that make it clear that you haven't even attempted to learn the basics. > > > Not so. The theory of relativity doesn't say that nothing comes out. > > Comic-book explications of relativity say so. But relativity fully > > affords the prospect of radiation emerging. It's been calculated by > > the theory, in fact. > > I know. The point I'm making is that the statement that "what goes in > must come out in some way" is perfectly consistent with intuition, And that intuition is WRONG. We have EVIDENCE that it is wrong. > but > then the black hole simply becomes a place of dense matter and high > gravity. I take your point though that comic-book treatments have > probably led to misconceptions, and that when physicists say "the laws > of physics break down" what the public hears is "physical laws break > down" and not "it turns out physicists do not know the physical laws > after all". And I agree that the way to learn physics is not to rely on material aimed for public, hobbyist consumption. Popularizations are aimed to intrigue and interest, and to spark further reading. They are NOT aimed to carefully educate. That is the difference between popularization and textbooks. If you want to LEARN a subject, stop reading popularizations and start reading more carefully prepared materials. > > > It is being able to make *distinguishing* predictions of measurable > > phenomena that are different than other theories that counts in > > science. Sorry, but that's what it is. > > I agree, but that proves my point, that if two broader conceptual > frameworks are competing to explain the same observations, then > something *other* than the scientific method determines which > framework is held to be correct. No! In *science*, it is ALWAYS the case that two competing models must differ in some prediction of measurable quantities or in scope of application. Any appeal to some other metric (such as the "more intuitively appealing" one you are clinging to) is OUTSIDE of science. > > > And I've already told you how that challenge is mounted: by making > > *distinguishing* predictions of *measurable* outcomes. > > But like I've already told you, that gives the incumbent framework an > advantage. No, it does not, if you stick to areas where there is accessible measurement. Any theory whose only distinguishing differences are in regions that are inaccessible to measurement is USELESS scientifically. > > > Unavailable for conversion means by ANY physical process, human- > > involved or not. This includes processes in the sun, at galactic > > centers, in plant cells, cosmic rays, whatever. > > Fair one. So I suppose we can test this hypothesis by asking for an > example of some thing that is unconvertible from its final state by > any physical process. That is, we'd expect to find somewhere a hard- > core of material or energy that is utterly unavailable to any physical > process or force. So, do you have such an example? Certainly. The thermal energy in a gas can only be *partially* convertible to useful work, even theoretically, where that fraction is determined by a function of the hot and cold reservoir temperatures. See the Carnot theorem and the Carnot cycle. This is material that is covered in a *freshman* physics class. > > > Consider Newton's first law, which describes the behavior of objects > > that are under the influence of zero net force. By *your* measure, > > this law would never be applicable and therefore would be a completely > > empty statement. Scientists vigorously disagree. > > The same goes for the laws of Mendelian genetics, which NEVER strictly > > apply. Are those empty laws? > > Yes. A law that only applies vaguely does not prove anything about the > underlying nature of the phenomenon. I rest my case. If you do not take Newton's 1st law and the laws of Mendelian genetics to be scientific laws, then you are simply in disagreement with science about what a scientific law is. This is another case where when using terminology that is used in science, it is important to know the meanings of the terms AS USED IN SCIENCE. > > > This tells you that the case with the air present is not a closed > > system unless the air is included in the system. And then, of course, > > the entropy of the system increases, though the momentum and energy of > > the system does not. > > > In the vacuum case, there are conversions of translational kinetic > > energy into thermal, stochastic kinetic energy (which increases the > > temperature of the balls). Again, energy and momentum are conserved, > > while entropy increases. > > But what is your point? I described exactly these processes that would > cause the toy to wind down. None of it proves that the entropy of the > universe has increased when the toy winds down. The entropy of the *closed* system has increased when the toy winds down. This is not a guess, it is an observation, because entropy is a *measurable* quantity. (And in a manner that is distinct from just "winding down".) It has a *value* that can be *measured*. > > > > > The other way is to prepare a state and then close the system, let a > > > > process operate, and then open the system and measure its final state. > > > > This can be done in such a way that the end-effects can be accounted > > > > for. > > > > But then you didn't measure a closed system. You measured an open > > > system - the system was open at the start when the initial state was > > > set, at at the end when the measurement was taken. A "closed system" > > > that is not closed for all time is not in fact a "closed system" at > > > all. > > > And that's nonsense. There is nothing in the definition (except your > > own) that a closed system is closed for eternity. > > Of course there is. That is the definition of a closed system, that it > does not interact with anything outside of it. Not so! What has to be true is that the interactions do not affect the variables being examined. And moreover, there is nothing that says that this must be true for eternity. A system can be closed for a period of interest only. > > > Not so! See my comment about Newton's first law above first of all. > > Secondly, your notion of closed system is not the same as what > > physicists mean by the therm. > > Of course not. Because of course a "closed system means what > physicists mean by it". We're really into the realm of Humpty Dumpty > here. > > Why don't you just accept that, whatever you mean by a "closed > system", the universe isn't such a thing, and therefore the laws of > thermodynamics (which are derived from observations of "closed > systems") do not apply to the question? I think it's going to be helpful for you to understand what the meaning of "closed system" is first, before you start asking whether this system or that system is one of the closed ones. Doncha think? > > > > Secondly it would have to have been closed, and remain > > > closed, for all time. > > > This again is NOT the meaning of "closed system" as used by > > physicists. It is purely your own. > > Of course. Because you're a physicist. And that's not what you meant > by it. That's RIGHT. And since the 2nd law of thermodynamics is about the behavior of entropy in a closed system AS THAT TERM IS UNDERSTOOD BY PHYSICISTS, and not necessarily as that term is understood by you, then it serves no value to ask questions about the 2nd law when connoting something else by "closed system". > > > > > What? Why? Continuousness does not imply isotropy. Anisotropy does not > > > > imply discreteness. > > > > I think you'll find it does. But if you have some examples where there > > > is both continuous-variability and anisotropy, then perhaps we can > > > discuss them. > > > Of course! The electric field surrounding a charge dipole is > > continuous. But it is anisotropic. > > Believe me, this is just one example. > > So the level of charge in the field can be infinitely large, and > nothing will ever happen that is liable to transform the charge into > another form of energy (i.e. there is no limit to the level of charge > that can be maintained for all time)? What? The electric field is the continuous quantity here. Does continuity imply to you that the variable has to go to plus infinity or minus infinity? Is the cosine of an angle a continuous function or not? Is the value of that function ever infinite? Do you have ANY idea what you're talking about? > > Or are we at cross-purposes here? > > > > It is non-deterministic, and it doesn't purport to explain why > > > the underlying mechanism cannot be determined. > > > OK, first off, I have to ask you WHY you think that any physical model > > MUST be deterministic. That is, it is your belief that any model that > > accurately describes nature MUST be deterministic at root, with the > > implication that nature itself MUST be deterministic. WHY do you > > believe that? > > It's not that nature must be deterministic, but that it is hard to see > how you can do science without determinism. Ah. And here is where your education really needs to take off. Just because YOU have a hard time understanding how a scientific explanation can not presume determinism does not mean a) that science has the same limitation and b) that nature has the same limitation. > Science doesn't really go > any further unless you believe there is an underlying physical > mechanism to be discovered. And indeed, there is nothing about the > world that leads us to believe that it is fundamentally probabilistic. > Everything before now that has appeared probabilistic has merely been > a complex system. I disagree. I suggest some reading on Bell's Theorem and the results of experiments by Alain Aspect and following. > > > > > > > Whether you believe it or not is not really relevant. What matters is > > > > > > whether there is any *evidence* that it is fundamentally reversible. > > > > > > This is where observation plays a key role and what separates physics > > > > > > from philosophy. > > > > > > Science does have a philosophy you know. > > > > > But it invokes things that philosophy does not, and this is the part > > > > you ignore. > > > > Such as? > > > Experimental test! > > Just to clarify, are we talking about what might be termed the > 'principles of science', or are we talking about "what scientists do"? Both! Experimental test is *essential* to the principles of science, and it is what scientists do. > > > > > And you are the one that is complaining about nonintuitive ideas like > > > > wormholes, etc. > > > > No, I'm complaining about ideas like wormholes (or singularities, > > > classical time, etc.) that *remain* counter-intuitive even after > > > exposure to the concept. > > > I'm sorry, but there's nothing counterintuitive about wormholes or > > singularities or classical time. Just because YOU have difficulty > > being comfortable with the concepts doesn't mean that experience is > > shared. A little humility, please. > > I'm not saying everyone has difficulty with them. All I'm saying is > that those who do not have difficulty with them do not impose on > themselves the rigor of reality. Which means WHAT exactly? And how do you determine what the rigors of reality are, INDEPENDENT of your intuition? After all, reality is what it is, whether that makes sense to us or not. What nature IS, is what's rigorous, whether we find that loosey-goosey or not. > > > > If science is defined merely as "what scientists do", then > > > that is a bulletproof rejoinder to anyone who points out that what > > > scientists are regularly doing is not at all in accordance with the > > > commonly-apprehended principles of science. > > > Then perhaps the "commonly-apprehended principles of science" are > > misapprehensions, eh? > > Perhaps. I know a lot of law, and concepts like "reasonable" > notoriously mean quite different things to lawyers than they do to the > man on the street. Of course, I might be forgiven for assuming that > when you appealed to the "principles of science", you meant you were > appealing to some objective principles which could be compared to what > scientists actually do. > > > If you want to know what science is, ask a scientist. If this > > conflicts with your common apprehensions, then consider those > > corrected. > > Of course, that presupposes that scientists know explicitly what they > are doing, and are both able and willing to communicate it. They are. Just not necessarily in the customer's venue of choice, such as a free discussion newsgroup. This is the reason why there are schools, you see. > > > > > > The question is whether *any* coherent theory requires it. I haven't > > > > > heard any explanation yet for why the curvature of spacetime is > > > > > distinguishable from forces acting acting on matter in the classical > > > > > way in Euclidean space. > > > > > Because they make different predictions of observable phenomena! You > > > > aren't aware of these? > > > > Indeed I'm not aware of any observable phenomena that cannot be > > > trivially described in 3 dimensions. Even the effects of SR can be > > > readily understood in 3 dimensions. Of course I'm willing to be > > > corrected. > > > Wait a second. Let me see if I understand you. You are saying, "My > > present understanding of nature requires only three dimensions. If > > nature exhibits itself to require an understanding of more than three > > dimensions, then I'm not interested in such a model. That is, nature > > must conform to MY current parameters of understanding, and I will not > > accept any model of nature that does not accomplish that." > > Indeed, any model must conform to the requirement of > understandability, and secondly any model of the real world must > conform to the requirement of actually describing the real world. And > you have to ask yourself whether a theory that rests on multiple, un- > navigable dimensions, is not losing touch with mechanisms of action in > the real world. OK, a couple of comments here. When you say that any model must conform to the requirement of understandability, this is an onerous and irrational requirement, because there is the question of "understandable by whom?" and "by when?" and "with what level of background?" What is true is that any model that makes the best match to experimental observation in the widest set of applications is the one that wins, EVEN IF the lay public finds that model completely confusing and difficult to understand. What is often found is that experimental results defy common expectations and intuition. In those events, it is intuition that must give way EVERY TIME. What is certainly true is that every model to date is certainly understandable, because there are at least a handful of people working on it who do understand it at an intuitive level. What happens then is that there is the incontrovertible fact that the model does the concrete job of prediction demonstrably and objectively better than other competing models. This is used as the driver for those who do not presently understand it, to acquire that understanding, because it is most likely to be right. As for the second comment about unnavigable dimensions, one does not need to navigate them to have solid evidence for their existence. This is precisely the matter of *measurable* -- and I emphasize *measurable* -- predictions of those theories that speculate on their existence. We do not have to have a living, breathing dinosaur to know where, when, and that they existed, either. This is why I suggested the Lisa Randall book, so that you can get a feel for what some of those *measurable* quantities are. > > > > > Well, as it turns out, you may be interested in quantum eraser > > > > experiments. You can google that. > > > > I've studied it again now scrupulously and I don't find anything > > > shocking about it (even though the last page I read -http://www.bottomlayer.com/bottom/kim-scully/kim-scully-web.htm-said > > > as a layman I ought to be). > > > > Surely the outcome of the QE experiment is easily understandable if > > > you conceive of there being a sort of EM field (i.e. a potential > > > force, that "charges" space) which is distinct from the photon (i.e. > > > an energy packet causing observable change of state) itself? I know > > > that sounds like going back to the luminiferous aether, but it's > > > surely more physically credible that "action at a distance" or "a > > > particle in two places at once". > > > When you can come up with a model that can *quantitatively* predict > > those results like quantum mechanics can, rather than vaguely waving > > your hands and saying "Surely something simpler can be made to > > work..." > > There is no need to sell one's soul to the devil for a predictive > theory! That is, whether you like it or not, the bread and butter of science, and the sole figure of merit of a scientific theory. > Clearly, the maths of quantum mechanics works to some degree. > The question is whether the premise that it rests upon, of the > "photon" being a particle of some sort, is correct, and clearly the > QEEx ought to prove to any sane person that the premise isn't correct. That's not the point of the quantum eraser experiment. It's apparent that your background in the development of quantum mechanics is also seriously deficient -- but that would be easily solved with recourse to a *freshman* physics *textbook*. In the interim you may want to look up single-photon detectors, the photoelectric effect, direct photon production experiments, gamma rays, and facilities like the Advance Photon Source. |