Many theists believe there is an objective morality to be discovered. However, since you can't uncover such a morality in the same way you can lift a stone and find a pill bug, empirical systems are not use for this process. Instead, many rely on various works that they give implicit trust to, except when the advice of such books goes against their innate beliefs. Hence, we see homosexuals barred from military service, but don't see single women non-virgins barred in such a fashion, much less executed for being a single non-virgin.
Some attempt a seemingly more sophisticated approach of creating a morality based upon a few accepted notions and creating a formal system to reflect it. That's when you see people like the Maverick Philosopher examining the details on what their basic positions entail when examined in detail. Below the fold, I'll go into why I think this helps to pinpoint the inherent lack of objectivity in this construction of a moral system.
I'm not really concerned with the particular argument that Dr. Vallicella is making in his post, rather, I want to highlight what happens when he finds his argument is inadequate. In particular, he doesn't like the breadth of the conclusion of the argument, so he proposes a new starting point. That is, in creating this supposedly objective moral position, he changed his starting point to get the conclusion that he felt was the right one.
Now, I have no objections to this activity per se. In fact, this is one of the better advantages of operating strictly within a formal system. If the starting positions lead you to a situation you can't use, changing the starting positions is to be expected. If you are tracking the movements of ships on the surface of the earth, you don't pretend that the surface of the earth matches Euclid's parallel postulate; instead you assume that no lines (aka great circles) are parallel and use a Riemannian geometry. It will have the tools you need to look at ship movements around a globe.
However, the process of choosing these starting positions is strictly based on the conclusions you want to derive. That makes the starting positions arbitrary, and those positions will be carefully chosen so the results conform to the desired outcome. So, far from getting some objective morality that can be applied to all, you get a tailored morality designed to support a specific set of positions. Some of these systems, like natural law, were debated for hundreds of years before they were codified, and even then still generate disagreements around the edges.
When people come up with another method of knowing things that can exhibit certainty, reality, and demonstrability, that method of know may indeed lead to an objective morality. Until that time, there will be no such creature. All the construction within formal systems will not be able alter the shaky foundation upon which they rest.
Tuesday, December 7, 2010
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«Oldest ‹Older 601 – 800 of 2208 Newer› Newest»Al himself goes on to use his operational definition of "simultaneity" to show (as does the author we have been discussing) that it will not be met by a passenger at the midpoint of a moving train BECAUSE the midpoint is moving in that case:
"If an observer sitting in the position M’ in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated. Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A."
But at least he does not make the same mistake as our author. He has already said that "in reality" they are moving, he then concludes that: "Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B took place earlier than the lightning flash A."
The problem is that Al here is conflating perceptions with necessary "conclusions." There is no reason they MUST come to such a conclusion. Given their situation there is a good reason for them NOT to come to such a "conclusion" (conclusions being distinct from raw perceptions). There IS a reason while they will perceive it that way, which he has just elucidated. But, and here's the important point, their conclusion would be erronous if it matched their perceptions, because "in reality" they are moving, Al says.
What he should have said is "Observers who take the railway train as their reference-body must therefore HAVE THE PERCEPTION [not "come to the conclusion"] that the lightning flash B took place earlier than the lightning flash A."
What Al really means is that they must PERCEIVE the flashes as non-simultanous. But that alone would not force them to conclude that their subjective perceptions are accurate, or represent "reality." By Al's own presuppositions, they are moving with respect to the tracks and therefore to the stationary observer he used to create his operational definition of simultaneity. Therefore the train passengers have every reason to believe that their misperception of "non-simultaneity" is simply a product of their motion, and not of "reality."
Unfortunately, like our author, Al is trying to suggest that his "operational definition" of simultaneity for a stationary observer would ALSO apply to a moving observer. But it can't. It's not the same definition in that case. He is equivocating on his use of the term "midpoint" if he tries to equate the two. A moving "midpoint" is NOT the same "midpoint" as is a non-moving midpoint. The "midpoint" for the passengers on the train is different from, not the "same as," the midpoint for the stationary observer. To treat them as though they are the same would simply be a fallacious form of equivocation, i.e., a case of using the same term to designate different things, and then claiming that, since the term is the same, the two things must be the same thing.
Can you see that, Eric?
Another problem with Al's "operational" definition, apart from the equivocal application of it to train passengers, is the question of whether it's really accurate.
Again, his idea (definition) is more or less this: Measure, say, 10 miles each way in opposite directions from a "midpoint." Send light flashes, at the same time, from each of those points back toward the midpoint. If they reach you at the same time, then they were sent simultaneously.
But the question is: Would they reach you at the same time? Al simply implicitly assumes that they would.
But his example presupposes railroad tracks which are laid on a rotating earth. Given the Sagnac effect, they would NOT reach the midpoint at the same IF they were in fact sent simultaneously. If they were actually sent simultaneously, they would reach you at different times (assuming and east/west axis, at least).
They would not reach you at the same time for the very same reason they would not reach the train passengers at the same time, i.e., because you have a moving midpointt on a rotating earth. His example "seems" to be one where the two emission points have been established, as a matter of actual measurement, not mere "deduction," to be equidistant from the midpoint. In one sense they are. But not in the sense that they would be equidistant for the purpose of measuring light coming from each direction. That's because the "distance" from the emission points to the midpoint would be constantly changing (due to the earth's rotation) while the light beams are "in transit." They are NOT equidistant for that purpose.
Again, an "operational definition" does not automatically eliminate all problematic aspects of the definition.
So, kinda summarize my thoughts on time, distance, and "speed," let me recap with these prior points in mind.
1. The distance from NY to SF *IS* (really) the same as it is from SF to NY. It (the distance) does not change, depending on which way you are travelling. Two equally accurate odometers would end up registering the same number of miles if one were in a car going east to NY (from SF) and the other was in a car going west to SF (from NY)
2. That does not mean you would get there in the same amount of time driving each way. That would of course depend on your speed. That said, your speed, whatever it is, does NOT define the time it takes to get there. Time is a function of regularity, not "speed." One revolution of the sun by the earth, for example, takes the same amount of time (one year) whether you spend that year sitting still, driving a car at 100 mph or flying a jet at 1000 mph.
3. Your speed is determined by dividing the actual distance travelled by the actual time elapsed, not vice versa. In other words, the speed at which you might be moving does not dictate either the time elapsed or the "actual" distance travelled.
So, what about the travelling twin in the twin paradox? He is said to age more slowly. Let's assume he "really" does. Would that because "time itself" slowed down? No, it wouldn't. The earth would have still completed 10 full revolutions in 10 years, whatever speed he is going, or whatever speed some other person or object might be going somewhere else in the universe. If he returns in 10 years, but has only aged 5 years in the interim, it is NOT because time itself slowed down.
It could only be because, for him, due to his faster speed, the rate of all recurring phenomena, including such phenomena as the ticking of his clocks, his respiration, his metabolism, his heartbeat, etc. have slowed down while he was moving. It seems mysterious that a mere change in speed could effect the rate of all recurring processes, but, as they say, relativity can be difficult to fathom.
When Magellan circumnavigated the globe an extremely accurate log was kept. Once he returned to Spain (or Portugal, or wherever he came from) about a year later, the logs were a day short. It was soon concluded that the missing day was due to the fact that the earth had been rotating while he was sailing, and he therefore "lost" a day.
So, did the duration of a year change for him? did his year only contain 364 days, while everyone else's contained 365?
No, the duration was the same for both. Magellan only saw 364 separate risings and settings of the sun, but the duration of the year was still the same. Nor did the length of a "day" change as we define it. Neither the length of a day nor of a year "really" changed just because his perception of those things was slightly different, due to his motion. Perceptions do not change time or distance anymore than "speed" does.
I said: "It seems mysterious that a mere change in speed could effect the rate of all recurring processes, but, as they say, relativity can be difficult to fathom."
Perhaps no more or less mysterious that the strange effects temperature changes can have, though, eh?:
"Suspended animation is the slowing of life processes by external means without termination. Breathing, heartbeat, and other involuntary functions may still occur, but they can only be detected by artificial means. Extreme cold can be used to precipitate the slowing of an individual's functions; use of this process has led to the developing science of cryonics. Cryonics is another method of life preservation but it cryopreserves organisms using liquid nitrogen that will preserve the organism until reanimation. Laina Beasley was kept in suspended animation as a two-celled embryo for 13 years."
http://en.wikipedia.org/wiki/Suspended_animation
"Laina Beasley was kept in suspended animation as a two-celled embryo for 13 years."
Laina, one of three triplets, had two "twins" who were already 13 years old when she was born. Did "time itself" slow down or stop as they were aging, while she wasn't?
I don't think so. If it would have, then they too would have been born at the same time, not 13 years earlier, and they too would have been newborns when Laina was. Laina was just a little slow--retarded, ya might say, that's all.
I noticed there only 7 posts on the last comment page, even though the counter said there were 22. Fun, eh?
Also, I did read every word you posted and looked at the links. Any parts I have not responded to, I generally agree with the point you are making from the point of view you are using.
I guess I didn't answer that particular question because I don't understand what you are asking.
You pointed out that the path you take between two points changes the distance you travel, but not the distance between those points. My questions relates to whether you can see this applying to time. Without getting into how you would change a path in time, is time the sort of thing we have a path (schedule, if you prefer) in, much like we move in a path through space? Or, is time fundamentally different in that regard for you?
But the author also clearly implies that the light DOES not have to travel the same distance to reach him, and you agree with this. Therefore that assumption is, by the author's own premises, WRONG.
We know his presumption is wrong because we know the train accelerated.
I assume you agree, but I could be making a wrong assumption here. Do you agree?
Yes.
Of course, this (latter) is as it should be, since speed is computed reference to time and distance. Distance is not defined by speed.
I have no problem with this, but you do realize this is a philosophical preference, right?
3. The mere fact that no "natural choice" may be readily apparent to me also says nothing about what "choice" accurately reflects nature.
However, sometimes even when there is no obvious choice, we need ot make a choice of reference just so all the units are judged the same way.
4. And, of course, the simple assumption that even if you have two (or more) options from which you can choose, then regardless of which one you do choose, they can't BOTH be the "right" choice if they are mutually exclusive and contradictory.
True. However, each can be equally useful in accurately describing the situtation and making prediction (aka "valid"). So, when we are looking at the movements of two meteorites and how they effect each other, we can remove from our calculations the need to worry about which reference frame is the "true". Any inertial frame will allow us to make predictions.
We don't seem to think so. We seem to think we can just cut straight across "curved space" unaffected.
If space is curved as GR suggest, and you follow the light beam that you think is going "staight" to Mercury, you are following the curvature of space already. All light beams do so. If we think we are going straight, it's because in the practical experience we have the difference between following a straight line and following a geodesic if far below our ability to tell them apart, so we abstrct our movement into the simpler idea. If you wanted to follow a Euclidean straight line, you would need to point away from Mercury for a little while.
Einstein's light postulate is invalid ...
The refer to "Postulate I*: The velocity of light in free space is a constant c irrespective of the velocity of source or receiver in any coordinate system which is not in rotation." The current version would be "any inertial system". I'm not sure what the 1907 version was, but nothing in their paper addressed the current version.
I said: "4. And, of course,... even if you have two (or more) options from which you can choose, then regardless of which one you do choose, they can't BOTH be the "right" choice if they are mutually exclusive and contradictory."
This author routinely and consistently ignores this logical "truth" when he says such things as: "Both Alice and Bob are completely correct."
They both form a workable model. However, youare looking for a different idea of correct than the author.
The question he is asked is: "According to relativity, two moving observers always see the other moving through time slower. Doesn’t one have to be faster?"
His answer is "no." His answer is also wrong. By his own reasoning, and that of SR, the one which has been previously accelerated is faster.
The questions is what they see, but I agree the answer is wrong. For example, in the twin paradox, when the ship twin returns (but not on the way out!), he sses his earth twin's clock running slower, while the earth twin does not see this for the ship twin.
If this is correct the Sagnac effect has nothing to do with rotations and accelerated motion, rather it is a peculiarity of relative motion relevant to the old debate about the one- or two-ways measurement of the speed of light."
Yes, if that is correct. Since the light in questions when through different inertial frames, it's not surprising the sppeds would seem different.
If you haven't proven your assumption, then you certainly haven't proven your conclusion, even if it necessarily follows from your conclusion. And, needless to say, it would be fallacious (affirming the consequent) to say that, if your conclusion turns out to be true, then that proves your premises are true.
One of the many reasons I read "proof is for mathematicians" from scientists.
Can you see that, Eric?
I can see the point you're making, sure. You're aiming for a notion of correct scientists seldom fuss about. I can see why that might annoy you.
If they were actually sent simultaneously,
You are trying to use an absolute notion of simultaneous. It's a nice idea that we as of yet have no method to realize in pratice. So, Einstein used a model that had ideas we could realize and work with.
One Brow said: "I noticed there only 7 posts on the last comment page, even though the counter said there were 22. Fun, eh?"
Eric, I have found that if I go to the "newest" page, and, from there, click on "older," then I will see the posts which the blog apparently considers to be 601-615. They will follow the comment which was formerly designated as 600.
One Brow said: "I have no problem with this, but you do realize this is a philosophical preference, right?"
Well, you can view it that way. I suppose most scientists, and other people, have a natural "philosophical" preference for internal consistency. They can understand A = A without difficulty. They find it difficult to process or comprehend that A does NOT equal A. That second statement could only seemingly be consistent IF one is equivocating.
Implied in the assertion that A = A are such qualifications as "at the same time, in the same respect, from the same perspective, etc." Hericlitus can, with good basis, claim that it is impossible to step into the same river.
twice. But, in such a case, the "same river" (A) is not really the same river at the same time, in the same respect, from the same perspective, etc.
Does "the Mississippi River" (A) = "the Mississippi River?" In one sense, yes; in another, no. So it is important to understand what what intends by "A."
I said: "The problem is that Al here is conflating perceptions with necessary "conclusions." There is no reason they MUST come to such a conclusion. Given their situation there is a good reason for them NOT to come to such a "conclusion" (conclusions being distinct from raw perceptions)."
Think about it...Everyday, perhaps hundreds or thousands of times a day, we routinely reinterpret (correct) our "raw perceptions" in order to arrive at "conclusions" that differ from our raw perceptions.
For example, suppose I'm out on the ocean and see what looks like a luxury cruise liner that is only an inch or two long. Do I say: "Wow! There goes a miniature model of an ocean liner!" Of course not. I immediately assume that it is a "full size" liner which happens to be many miles away.
If I'm also on an ocean liner, the people on the other liner will perceive (and similarly correct their perception of) my liner the same way. Anyone who would try to literally claim that (1) Both see the other's ship as shortened, (2) Both are correct, so, therefore (3) both ships REALLY are shortened would be laughed out of town.
It is tautological to say "I see what I see." As a tautology, my subjective perceptions simply CANNOT be falsified, no matter how inconsistent they might be with "reality." However, if I try to give my raw perceptions some concrete "meaning," rather than merely describe them, then I have entered a realm where my "perceptions" (or, more accurately, my interpretation of my perceptions) can indeed be WRONG.
Al was trying SO hard to realize, in his scientific theories, the philosophical ends he desired, that he tried to equate raw perception with legitimate "conclusions" in order to give the appearance that his ends had been met.
This is just one of many ways in which both the creation and the interpretation of a "scientific theory" can be heavily influenced by philosophical premises (prejudices).
Neither the creation, nor the interpretation, of a "scientific theory" is a matter of cold, unbiased objectivity. Same is true for moral theories, of course.
I said: "Anyone who would try to literally claim that (1) Both see the other's ship as shortened, (2) Both are correct, so, therefore (3) both ships REALLY are shortened would be laughed out of town."
Well, by the majority, anyway. There would also be that naive minority who would see this claim as a profound philosophical insight which revealed the deep, hidden truth, I spoze.
One Brow said: "True. However, each can be equally useful in accurately describing the situtation and making prediction (aka "valid"). So, when we are looking at the movements of two meteorites and how they effect each other, we can remove from our calculations the need to worry about which reference frame is the "true". Any inertial frame will allow us to make predictions."
Yes, I agree entirely. That's what I'm trying to say, too. However, all too often, people, even scientists, think this means, or personally intend to mean, that the two views are "equally valid" in "reality' (i.e., are "equally valid" as a matter of objective physics, rather than simply mathematically).
That when the confusion really starts.
One Brow said: "You pointed out that the path you take between two points changes the distance you travel, but not the distance between those points. My questions relates to whether you can see this applying to time. Without getting into how you would change a path in time, is time the sort of thing we have a path (schedule, if you prefer) in, much like we move in a path through space? Or, is time fundamentally different in that regard for you?"
Well, some of the posts I made subsequent to that one (the "magellan" post, just for one example) were directed toward your question, if I now understand it correctly. If there's still some question I'm missing, let me know. If you rephrase it, I might understand what you're asking more correctly.
One Brow said: "You are trying to use an absolute notion of simultaneous. It's a nice idea that we as of yet have no method to realize in pratice. So, Einstein used a model that had ideas we could realize and work with."
Well, Eric, I think you are overlooking some of the main points I am trying to make here. For example:
Despite his claims to the contrary, Al did NOT use, or "work with," his presumably "operational definition at all. That is, he did not use it to go out and "test" it, which, he says, is it's sole purpose.
What he DID do, is to immediately that his defintion was physically correct. This becomes apparent when he starts discussing the passengers on a train. There he says:
"If an observer sitting in the position M’ in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated."
He is telling what a non-moving observer "would" observe. He obviously didn't test this, or else he would know his assumption was false (due to the Sagnac effect).
That's just how quickly a supposed "operational defintion," supposedly designed for the SOLE PURPOSE of establishing a concrete example to "test," can be turned into an assumption of actual fact.
Of course, that (mistaken) assumption of fact soon leads him to deduce other supposed "facts," and so on, on down the line to points where he essentially claims his finished theory reflects "fact."
There is a reason why the "one way speed of light" is still debated, and that "reason" is not "because demented cranks like Van Flandern exist."
"
I am now at the point where, having responded to some of your other posts, and then later seeing them posted, they are now gone. If this recurs, I will simply quit posting until this thing straightens itself out. To do otherwise would just create waste and confusion, I figure.
One Brow said: "The questions is what they see, but I agree the answer is wrong."
No, the question is not what they see. In the introduction to his question, the interrogator summarizes the claims of SR about what they see, but that's not his question. His question is: "Doesn't one have to be faster?"
Going back a way now:
One Brow said: "My understanding was that Michelson-Morley was a test to detect ether, not absolute motion."
Well, the idea was that the "absolute motion" of the earth (at the rate of 30 mps around the sun) through the ether would be revealed by this experiment. As a sidenote, it is now claimed that a Michelson-Morley type of inferometer DOES reveal this motion (as well the the motion of the galaxy as a whole) but only if the inferometer is operated in gas mode. Failure to use "gas mode" (whatever that is) renders the inferometer incapable of detecting "absolute motion," they say.
What is more interesting to me (beyond the question of why we should even expect the motion of the earth to be detected by a Michelson-Morley inferometer) is the part this played in the acceptance of SR (which is probably relatively minor, compared to the role Minkowski's geometrical analogies played).
The picture I get is this:
1. As we know, Al was obsessed with symmetry, and felt that the perceived asymmetry of the Maxwell equations was intolerable. Whether that intolerable asymmetry could have been just as easily accomplished by Hertz's equations I will leave to others, more qualified, to decide.
2. Maxwell's equation's contained some factors which were dependent upon c. But the question was "c as measured with respect to what?"
3. Had the Michelson-Morley experiment detected the earth's motion, then a consistent (symmetrical) answer, applicable in all reference frames, could have simply been "c with respect to the (always non-moving) ether." In this sense, the detection of the ether was crucial, although the supposed "means' of detecting it was the "absolute motion" of the earth.
4. The absolute motion, and hence "non-moving" ether was NOT detected.
5. Lorentz (and Fitzgerald) came up with an equation which would explain why we did not detect the earth's absolute motion, even though we "knew," by virtue of the Copernican hypothesis, that it existed.
6. In essence, the Lorentz equations said (in an indirect way) that IF the speed of light was always X with respect to absolute space (the ether), then his equations would explain we would also arrive at the "true" speed of light (x), which was properly measured with respect to absolute space, not the earth's frame of reference, EVEN THOUGH we can't detect our absolute motion.
7. Enter Al. If we cannot "operationally" show that the c in Maxwell's equations is "c with respect to absolute space," then we can't have the same system of reference in ALL inertial frames of reference.
8. So the only way to make the c in Maxwell's equations easily transformable to ALL inertial frames, was to make c relative to each particular frame, whatever it was.
9. Since Lorentz's transformations already provided the equation for "transforming" the presumed value of c in the "absolute" or "universally preferred" frame, Al didn't need to do anything. He just extended Lorentz's equations for transforming c to one particular frame of reference (earth's) to ALL intertial frames, as Galileo had done.
[Continued in next post]
[continued from last post]
At bottom of the whole thing was the (essentially philosophical) demand for "symmetry." Even assuming that symmetry is indispensable, there are other ways of achieving it, probably including ways which required no "transformations" whatsoever, but rather interpret things in such a way as to conclude that there is no "actual asymmetry" to begin with.
Again, historical contingencies, subjective interpretation, and aesthetic considerations often play a major role in determining which of two or more "equivalent" alternative theories end up being accepted as "correct."
I find it ironic that many relativists, who want to insist that 'equivalence" must be acknowledged as something extremely significant, fail or even refuse to comprehend/acknowledge the "equivalence" of LR to SR.
Go figure, eh?
I would like to elaborate on one of my prior posts (one not currently being displayed) which may involve some repetition.
First, recall that Al was very reassuring that he was NOT assuming anything about the "nature" of light with his one-way speed hypothesis. He said:
"I maintain my previous definition nevertheless, because in reality it assumes absolutely nothing about light....That light requires the same time to traverse the path A —> M as for the path B —> M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity.”
But, even though he expressly states that he is making no "supposition or hypothesis about the physical nature of light," he turns around and does just that: He treats his implied claim as a "true" hypothesis about the nature of light.
He does NOT use his definition to actually TEST his hypothesis (which he first claimed was the only reason he created). He simply assumes, as an assumption about the nature of light, that he already KNOWS what the outcome of the experiment he is proposing will be.
The outcome, he assumes, will be that the two light beams coming from opposite directions WILL, in fact, reach the midpoint simultaneously. This would be contrary to the experiments detecting the Sagnac effect, which shows the two beams would NOT reach the midpoint simultanously.
That he assumes that he knows, a priori, what the experiment will show is clearly demonstrated in the very next section where he talks about the passengers on a train. There he says:
"If an observer sitting in the position M’ in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated."
You see what's happening here? It is in such disguised and subtle ways that assumptions get imported into an entire theory, all while the creator of the theory denies that he is making those very assumptions.
Another seemingly plausible hypothesis about the varying speed of light "in a vacuum" kinda stems from GR itself. As we know, we must know the actual time elapsed (in addition to distance travelled)to correctly and confidently pronounce the speed at which an object is travelling. If either our watches or metersticks are distorted, we will get an erroneous measure of at least one of the necessary components of speed, and will therefore calculate an erroneous speed as a consequence.
GR says that "time" (an essential component of speed) slows down the deeper one goes into a "gravitational well." Changing times would therefore seems to result in changing speed calculations.
It has been suggested that this type of consideration could account for the seemingly anomalous "pioneer effect." The suggestion is that the farther way from the center of gravity of the solar system (basically the sun) the pioneer gets, the faster it's "clocks" tick. Given our ways of "communicating" with the pioneer (which I don't purport to fully understand) and given our a priori assumption that the speed of electromagnetic waves is constant, we assume that the pioneer should be in a position which it isn't. At least that's one claim. If true, it would to be just another strike against the unqualified assertion that the speed of light in a vacuum does not vary.
Actually there seem to be a lot of phenonmena, including many at the quantum level), that can be most easily explained by assuming the the speed of light is NOT constant.
I don't find the suggestion that the "constancy postulte" of SR could be advantageously abandoned at all repulsive when LR, which abandons this postulate from the get-go, gives all the same predictions which SR does.
Nor do I see why anyone else should find it so repulsive, given the circumstances.
One Brow said: "They both form a workable model. However, youare looking for a different idea of correct than the author."
How is a model which says "They're both completely correct" workable in any way? That isn't SR's model, because SR does NOT conclude that "both are correct," does it?
If "both are correct," then each twin would in fact be younger than the other. That seems to be logically impossible. But, even assuming that logic is totally irrelevant, and that "anything is impossible, no matter how illogical," it still is NOT the conclusion SR reaches, is it?
What is this author's "idea of correct," ya think?
And, again, how is the "model" that "both are correct" workable? It's not SR's model, but evidently an entirely new model independently devised by this author.
One Brow said: "youare looking for a different idea of correct than the author."
Second question: Once you tell me what this author's "idea of correct" is, can you tell me why in the world he's "looking for" that idea?
It seems me that we have both agreed that, although Bob's logic is correct, his premises are wrong, so therefore his conclusion is wrong.
Why would this author want to insist that a wrong premise is "correct?" What is the benefit of calling wrong "correct"
http://www.pbs.org/wgbh/nova/body/suspended-animation-au.html
That is a link to a NOVA podcast (about 5 minutes long) where a cell biologist is interviewed. It is quite interesting, I think, and says, for example that seeds and spores can remain in suspended animation for hundreds of thousands, and even million of years. A case is also cited where a skier, exposed to cold, was "clinically dead," but came "back to life" after nine hours.
A couple of times, the cell biologist talks about "stopping" or "slowing down" time for the individual in question. What he is actually talking about, though, is reducing the metabolism rate, the rate of oxygen consumption, etc., and he makes that clear.
So, loosely speaking, "time slows down." But, all he is really saying is that the rate at which certain processes normally occur slows down. Is there a difference?
We "measure" time by counting the rate of certain periodic events. But are we measuring "time itself?" Or are we just measuring the rate of periodic events? This is basically the same question I asked you a long time ago, but I don't think you ever responded.
The question being: Is there a difference between our "measurement" of time, and "time itself?" (or our measurment of distance, and "distance itself"). One encounters grave logical problems and generates multiple consistencies if his response is "no, there is no difference."
When asked what time is, Einstein, in his full (at that time) positivistic glory, is reported to have said: "Time is what clocks measure." Is this "true?" Are the two things "identical?" Is Einstien's response just a form of tautology or is there some profound substantive meaning to it?
One man's meat is another man's poison, they say. Protagoras said: "The same wind that feels cool to one man can feel warm to another. Therefore the same wind is both hot and cold."
Was Protagoras right? If so, in what sense what he right? Protagoras is obviously equating(as Einstein was prone to do) "what is perceived" with "what is" (real). Is this strictly the subjectivist view of reality the correct one, as Berkeley claims, ya think?
Edit: Probably obvious, but I meant to say:
One encounters grave logical problems and generates multiple [IN]consistencies if his response is "no, there is no difference."
Well, some of the posts I made subsequent to that one (the "magellan" post, just for one example) were directed toward your question, if I now understand it correctly. If there's still some question I'm missing, let me know. If you rephrase it, I might understand what you're asking more correctly.
Your Magellan response addessed the traking of time by recording sunrises and sunsets. However, I think we would agree that he experienced approximatelyh the same number of hours, even though there was one less sunrise. I'm not asking if you can see recording time in different ways or different circumstance will give different results. I'm asking if you think there can be a physical reality to changing a path in time, just as there is to changing a path in space. However, your very inability to see the question can be asked is probably my answer.
He is telling what a non-moving observer "would" observe. He obviously didn't test this, or else he would know his assumption was false (due to the Sagnac effect).
I don't think the movement of the train in a line is technically the Sagnac effect.
There is a reason why the "one way speed of light" is still debated, and that "reason" is not "because demented cranks like Van Flandern exist."
It's because scientists don't have any specific evidence, and so are reluctant to draw conclusions.
I am now at the point where, having responded to some of your other posts, and then later seeing them posted, they are now gone. If this recurs, I will simply quit posting until this thing straightens itself out. To do otherwise would just create waste and confusion, I figure.
Defeated by the spam filter? Have let any of your comments languish there?
It seems me that we have both agreed that, although Bob's logic is correct, his premises are wrong, so therefore his conclusion is wrong.
Why would this author want to insist that a wrong premise is "correct?" What is the benefit of calling wrong "correct"
Because when you don't know that Bob is the one who accelerated, you don't want to allow that position to stop you for analyzing the situation.
Second edit:
I said "We "measure" time by counting the rate of certain periodic events. But are we measuring "time itself?" Or are we just measuring the rate of periodic events?"
I keep mistating this, and thereby create confusion. That sentence, as written, does not express what I meant to say. We don't count the "rate," we count the number. We then establish the "rate" by comparing it to "time elapsed."
It therefore follows that we must ALREADY have an (independent) notion of time elapsed before we can talk about the "rate" at which periodic events recur. So, logically speaking, we cannot get our concept of time from counting events. That is because the raw number of events, considered without regard to time elapsed, can tell us nothing about time. We must have a notion of time first, and then apply that notion to the number we count in some way that we presume is meaningful.
One Brow said: "I'm asking if you think there can be a physical reality to changing a path in time, just as there is to changing a path in space. However, your very inability to see the question can be asked is probably my answer."
Well, you're right, I guess. The phrase "path in time" seems to have a very clear denotation in your vocabulary, but it doesn't in mine. What is a "path in time?" What are you trying to convey by using this phrase? Are you referring to a geometrical concept?
I asked: "Why would this author want to insist that a wrong premise is "correct?" What is the benefit of calling wrong "correct"
You responded: "Because when you don't know that Bob is the one who accelerated, you don't want to allow that position to stop you for analyzing the situation."
Well, I can definitely see the benefit of not having your powers and methods of analysis curtailed or eliminated. What I can't see is how the two things are related. Would I have to assert that "Bob is correct" (even when I know he isn't) in order to "analyze" things from his perspective?
Would I have to assert that "it is correct that the the sun revolves around the sun" in order to have the ability to "analyze" things from a geocentric perspective, for example? It doesn't seem necessary to me
One Brow said: "I don't think the movement of the train in a line is technically the Sagnac effect."
Well, whatever you want to call it, it is the "same effect," I figure (a "midpoint" that is moving).
We just recently discussed experiments reported in a wiki article on the "sagnac effect," and articles(s) cited therein, which concluded that the "sagnac effect" has nothing to do with rotation per se, and also applies to "linear motion." But again, it is not important to me if the effect I'm referring to is called the "sagnac effect" or not, as long as you understand the "effect" I'm talking about.
Here's what SR is essentially telling us, as I see it.
If I ask a relativist what the "speed of light" would be in the absolutely motionless frame of the ether, he will probably say:
WE CAN"T KNOW WHICH FRAME THAT IS!!
I will then say: Assuming that the claim you just made is absolutely true, it's not responsive to the question. I just asked you what the speed of light would be, not whether we could detect that frame.
Now, to be consistent, the relativist would have to say 186,000 mps. Such a frame would be an inertial frame, and the speed of light is 186,000 in ALL inertial frames (including this one) per SR.
OK, so now we have 186,000 mps in the motionless ether frame. So what is it in the earth's frame, which we know is "moving" around the Sun?
His answer: The same, 186,000 mps.
My next question: Why don't we get a different speed, then, since we're moving, and it isn't?
His answer: Because you must apply the Lorentz transformations to the earth's frame to make it "equal to" the absolute rest frame of the ether. On earth, your rods contract and your clocks slow down relative to the ether frame.
So, in essence, Al simply supplied a formula which explains why, relative to the absolute rest frame, every other inertial frame has it's rods and clocks distorted.
Do you agree?
Now, extending this to the twin situation, the only conclusion would be that, as between the earth's frame of reference and the frame of reference occupied by the motionless ether, it is the earth's rods and clocks which have "really" been distorted, while those in the motionless ether frame remained unchanged. And, of course, being "always" motionless, with respect to all other inertial frames, the rods and clocks in the ether frame would therefore be the ones which never "really changed." Only rods and clocks in other frames "really change."
Where would Al be, without the absolute rest frame as an ultimate reference point?
Not nowhere, that's where.
Needless to say, the relativist would want to come back and say something like this to me:
You're forgetting on thing about SR. If you are on earth and, from earth, you looked at the rods and clocks in the motionless frame of the ether, then you would perceive the clocks and rods in THAT frame to be distorted.
My response would be: No, I'm not forgetting that at all. You're right, that is how I would see the rods and clocks in the absolutely motionless frame. I didn't forget that SR tells me that. I simply remembered that SR also tells me that I would be WRONG in my perception of the rods and clocks in the motionless frame, because, with respect to it, I am the one moving.
I said: "My response would be: No, I'm not forgetting that at all. You're right, that is how I would see the rods and clocks in the absolutely motionless frame."
But, what I am really saying here is that I would "see" the rods and clocks in the absolutely motionless frame to be distorted IF, and ONLY IF, I presupposed that *I* was absolutely motionless. If I didn't make that (false) assumption, then I would "see" my own clocks and rods as being distorted, NOT those in the motionless frame.
In that case, I would reach the correct conclusion, because it would be based on the correct assumption, instead of a false one.
I would kinda like to tie the things I've said back into "moral theories" somehow. To do that, I'd like to first discuss a couple of general "truths" about human thought and perceptions.
I saw a video which demonstrated how a particular "optical illusion" works once. It's hard to explain, in words, but I'm gunna try.
In this video, right in front of you, was a large rectangle, like a picture frame. The rectangle appeared to be rotating at a relatively slow pace. It just kept making one 360 degree turn after another (it was mounted to a pole which ran through it's (empty) center, or something, I forget exactly.
Everyone who saw it seemed to agree about what they were seeing. Then the "rectangle" was shown from a side view. It was not actually making 360 degree revolutions. It was making 180 turns, and then reversing directions.
OK, so what? Well, the "illusion" was created because it was NOT a rectangle, and not even close to being one. It was a strongly skewed parallelagram, or trapazoid, or something. The "image" it gave was the same you would get if you WERE watching a true rectangle rotate 360 degrees, that's all.
Two points can be made about this, one perhaps less obvious than the other:
1. If you are watching a true rectangle rotate, the images you see will NOT maintain the actual dimensions of a rectangle. Even so, our tendency is to naturally "adjust" our perceptions in such a way that we "see" it as a rectangle the whole time. We "expect" a rectangle to change it's literal appearance "as a rectangle" as it revolves, so the changing appearance is simply "to be expected."
2. It was claimed, however, that members of certain other cultures were much less likely to be deceived by what they saw. They were much more likely to report that was they saw was a parallelogram making a half revolution, then reversing directions. These "other cultures" were ones where "grass huts," hollowed logs used as canoes, and such were the "norm" of architectural design, and where most shapes, sizes, etc., they looked at were "natural" ones like trees, rocks, rivers, or whatever. Right angles are rarely encountered "in nature," and these cultures were much less likely to "assume" that any four-sided shape they saw was rectangular.
So, it seems, even with "raw perception," what we "see" (i.e., how we interpret the "true meaning" of our perceptions) can depend a lot on what we "assume" about the things we are observing.
That's the first "general truth" I wanted to discuss. Second is in the next post.
If you take a "moral" issue, like, say, whether the death penalty, or abortion, is right or wrong, and present the question to people, the people you address will fall into 3 general groups:
1. Those who 'strongly believe" in the death penalty (staying with that),
2. Those who strongly oppose the death penalty, and
3. Those who have no "strong" opinion, either way.
Now, studies have been done where "persuasive" rhetorical presentations, both supporting and opposing the legitmacy and desirability of the death penalty, have been made and then presented to the various groups. Without going into all the variables, I'd like to discuss one set of the findings.
One form of the study was to select participants only from the groups who already had "strong opinions" and then have them listen to the presentation which opposed their favored view. The almost invariable outcome of this was that, after the "opposing" view was presented to them, they were EVEN MORE convinced that their pre-existing view was right than they were before listening to the presentation. Virtually every argument made was ridiculed as "stupid" and "totally unpersuasive" by these members.
Yet, when the same arguments were presented to people who started as "neutral" on the issue, the "persuasive" value of the same presentation(s) was generally rated as ranging from "persuasive" to "highly persuasive."
From prior discussions with you, Eric, I know that you will not find such studies to be the least bit surprising. In fact, you would probably say such results would be what you would expect to begin with.
To me, the somewhat surprising thing is that the opininated ones did not simply say their opinion remained "unchanged." They actually found the (opposing) presentations "highly persuavive" in a reverse sense because it actually helped "persuade them," even more, that their initial opinion was correct.
The moral? Well, I dunno, exactly. Maybe it's this: If you "really" want to persuade an opininated person to consider another view, maybe the best way is to tell him how indisputably right he is, and keep telling him all the reasons he's right. That way, he may feel compelled to "correct" you, now and again, and, in the process, perhaps change his own opinion to some extent.
But, more to the point, as with "raw perceptions," it seems the conclusions we reach may well be strongly influenced by our assumptions and expectations.
Whether the topic is moral or "scientific" in nature, pre-existing opinions, assumptions, beliefs, and preferences probably play a strong part in determining which "arguments" and which "observations" we are likely to emphasize and accept/reject. People don't stop being human just because they change the topic of conversation.
Well, you're right, I guess. The phrase "path in time" seems to have a very clear denotation in your vocabulary, but it doesn't in mine. What is a "path in time?" What are you trying to convey by using this phrase? Are you referring to a geometrical concept?
Would you call taking a different path in space a "geometrical concept"? If one day you decide to take State Street from 87th down to 7th to go the the hospital,and a week later you instead use Highway 15, is that a geometric concept? I can see where you you can apply geometric concepts to the path, and can'treally discuss it without geometric concepts. Is that what you mean? Because I mean a different path in just that sense, traveling a different way in time (and possibly going though a different duration) just as you would travel a different way in space (and possibly going a different distance).
It's not a concept we naturally consider, so if I won't be surprised if you think it's not possible. In fact, I rather expect it.
Would I have to assert that "Bob is correct" (even when I know he isn't) in order to "analyze" things from his perspective?
That depends on the point you are trying to make.
So, in essence, Al simply supplied a formula which explains why, relative to the absolute rest frame, every other inertial frame has it's rods and clocks distorted.
Do you agree?
I agree this is how you interpret relativity, and that your version is compatible with observations.
So, it seems, even with "raw perception," what we "see" (i.e., how we interpret the "true meaning" of our perceptions) can depend a lot on what we "assume" about the things we are observing.
No problem there.
From prior discussions with you, Eric, I know that you will not find such studies to be the least bit surprising. In fact, you would probably say such results would be what you would expect to begin with.
The first time I heard of this effect, I was a little surprised. But that was 3-5 years ago.
But, more to the point, as with "raw perceptions," it seems the conclusions we reach may well be strongly influenced by our assumptions and expectations.
Whether the topic is moral or "scientific" in nature, pre-existing opinions, assumptions, beliefs, and preferences probably play a strong part in determining which "arguments" and which "observations" we are likely to emphasize and accept/reject. People don't stop being human just because they change the topic of conversation.
I agree. However, there is also a strong difference and limitation between morals and scientific issues, which allow the former to be truly arbitrary based upon our subjective preferences and require the latters to be grounded. A moral claim that enoucrages cannibalism of the disabled can be shunned, villianized, and rejected, but you can't show it is wrong. If you have an idea of a moral position that you can demonstrate to be wrong )as opposed to inconsisent with other moral positions), what would it be and how would you demonstrate it? A scientific claim that the two-way speed of light in a vacuum on earth will be 450,000,000m/s can be proven wrong.
One Brow said: "I agree. However, there is also a strong difference and limitation between morals and scientific issues, which allow the former to be truly arbitrary based upon our subjective preferences and require the latters to be grounded."
Well, there are some issues that are strictly subjective, which are a matter of perception ONLY, and which cannot be said to be objectively true or false. An example might be: True of false?: Cherry pie tastes good.
The very substance of the question is about a sense perception here (taste) and that can differ which each individual. As I said before, sensations, per se, are unfalsifiable. Whether his conclusions about his perceptions is "objectively" right or wrong, a person still "sees what he sees."
But there is still a distinction between what one sees (as raw sense data) and what one concludes about what he sees. One can percieve optical images which he "concludes" are generated by a revolving rectangle and be wrong about his conclusion, even when no one can legitimately question or dispute the images he sees.
Is "the death penalty" just a "cherry pie" type of question? I'm not convinced it's merely that. If we're talking about "moral reasoning" (as opposed to raw emotional reaction) there are some "conclusions" involved, and, in that sense at least, it goes beyond mere sense perception. Some talk metaphorically about a "moral sense," and maybe there is something like that, akin to physical sensation. But, even if there is, the "moral sense" would not be the ultimate and sole arbiter of all conclusions about morality, any more than physical senses are about "objective reality."
Person A: The death penalty is always wrong, as a punishment.
Person B: The death penalty is sometimes the right punishment.
===
Person A: Special relativity is "right" in the sense that it accurately describes and explains what "really" happens in the physical world.
Person B: Special relativity is "wrong" in the sense just presented, and LR is correct.
Person A and person B disagree on two things, one of which is a moral issue, and the other which is a claim about objective reality as embodied in a scientific theory.
If the criterion is which one can be proven or demonstrated to be right, does Person A have any advantage over Person B (or vice versa) on either question?
I completely agree that physics and morality are distinct areas of inquiry, with some very significant and some very real differences pertaining to the nature of the topics being studied and the methods used to investigate them.
But I was not making a general comparison between physics and morality to begin with. I was comparing systematic moral theories with systematic scientific theories.
With either one, you can say, as a matter of logic, at least, that "if the premises are true, then the conclusions must be true." But, again, with either one, you cannot "prove" the premise. It is a starting point which cannot be proven or disproven within the context of the theory.
We can all ridicule, reject, and disavow the "moral theory" that child abuse is "right," just as we can the "scientific theory" that geocentricism is "right." But, ultimately, beyond appeal to conventionally-accepted notions, how do you prove either claim to be wrong? Geocentricism was deemed to be literally correct and indubitable by many brilliant men for many centuries. Strictly speaking, it still cannot be "disproven."
If, with respect to a moral theory, you accept the proposition that "action a" is wrong, and that "action b" is wrong, then you will conclude that "action c" is wrong if it entails action a or b. If you don't accept those propostions, then maybe you won't conclude that action c is wrong.
In the realm of moral theory one can, and perhaps often does, make an appeal to common or popular opinion to "establish" his premises. The exact same thing can, and often is, done with respect to the premises of a scientific theory. Beyond that, what is there, when it comes to the fundamental, axiomatic, starting point(s) of your theory?
One Brow said: "Because I mean a different path in just that sense, traveling a different way in time (and possibly going though a different duration) just as you would travel a different way in space (and possibly going a different distance)."
Well, the analogy still doesn't really compute with me, so I guess my answer to your underlying question would be "yes, I see time and distance as being fundamentally different things in certain aspects."
I can agree that apples and oranges are both "fruits," but I would not agree with anyone who said that they are the same thing in the sense that any claim that was true about an apple would also have to be true about an orange.
No, I don't believe that you can literally go "back and forth" in time, because time, as conceived (by me at least) is simply not the kind of thing that would permit such a thing.
In one sense, you can say that a person, born in 1000 A.D., put in suspended animation in 1010 A.D., and reanimated in 2010 has "taken a different path in time" than all of his long-dead contemporaries, and that he has therefore "travelled" into the future. But that would just be a strictly metaphorical sense, as I see it, and the very term "travel" is just a metaphor (making a comparison to space) when applied to "time."
For me, it makes no literal sense to suggest that you "travel through" time.
I asked: Do you agree?
You responded: "I agree this is how you interpret relativity, and that your version is compatible with observations."
Heh, quit fudging. How do you "interpet" relativity in a way that is different? For example:
1. Do clocks "really" slow down with increased speed?
2. Whether you answer yes or no, my next question would be: "Why is that, what is the explanation?"
Some talk metaphorically about a "moral sense," and maybe there is something like that, akin to physical sensation.
Even then, different people's moral sense will respond differently to the same stimulus.
But, even if there is, the "moral sense" would not be the ultimate and sole arbiter of all conclusions about morality, any more than physical senses are about "objective reality."
Let me know if you get a good candidate for a final arbiter.
Person A: The death penalty is always wrong, as a punishment.
Person B: The death penalty is sometimes the right punishment.
===
Person A: Special relativity is "right" in the sense that it accurately describes and explains what "really" happens in the physical world.
Person B: Special relativity is "wrong" in the sense just presented, and LR is correct.
As long as there is no empirical difference in the two theories, the preferences will be a matter of tase. Some people will find the the compressions in LR act too arbitrarily uniform on different obejcts for example, while others will submit your objection below.
I was comparing systematic moral theories with systematic scientific theories.
Even systemic scientific theories still need to be grounded in what happens. There are no systemic thoeries that the speed of light is 1,000,000miles/second in a vacuum. Can you come up wtih a moral theory that faces that sort of obstacle?
Geocentricism was deemed to be literally correct and indubitable by many brilliant men for many centuries. Strictly speaking, it still cannot be "disproven."
Perhaps, but the consequences of geocentrism are the loss of the principle of Conservation of Energy, but just for objects orbiting earth. In so doing, you toss homogenity out the door. When you do that, you no longer have a scientific position. Some positions can't be scientific, even if they can't be disproven. This is in contrast with moral positions.
Well, the analogy still doesn't really compute with me, so I guess my answer to your underlying question would be "yes, I see time and distance as being fundamentally different things in certain aspects."
In that case, I think the LET interpretations of the Lorentz equaitons are pretty much the only option open to you.
No, I don't believe that you can literally go "back and forth" in time, because time, as conceived (by me at least) is simply not the kind of thing that would permit such a thing.
I specifically excluded "back-and-forth" earleir, but suspect that is actually irrelevat to your answer.
Heh, quit fudging. How do you "interpet" relativity in a way that is different? For example:
1. Do clocks "really" slow down with increased speed?
2. Whether you answer yes or no, my next question would be: "Why is that, what is the explanation?"
1. No
2. The clocks themselves are not affected by relativistic motion.
However, if you can't conceive of the possibility of taking different paths through time, my explantion will just seem like abstract nonsense to you.
I asked: "Would I have to assert that "Bob is correct" (even when I know he isn't) in order to "analyze" things from his perspective?"
You responded: "That depends on the point you are trying to make."
Is science, or "objective reality," simply an exercise in polemics where the claims you make about what is "correct" are all-dependent upon the point you are trying to make? I don't see it that way. Let me ask you:
1. What "point" is this author "trying to make?"
2. Does his "point" have anything whatsoever to do with physics, or is it just a philosophical point along the lines of the one Protagoras was "trying to make" when he said:
"Man is the measure of all thing; Of thing that are, that they are; Of things that are not, that they are not."
2. Whether you answer yes or no, my next question would be: "Why is that, what is the explanation?"
1. No
2. The clocks themselves are not affected by relativistic motion.
So, then, do you reject the reported empirical finds of such experiments as the Hafele-Keating one (and others reportedly confirming it, to greater accuracy) that clocks actually register less time when moving.
The claim here (just a fictitious example) is that if two clocks are synchronized to both read 5:00 and one is then accelerated, then, an "hour" later, once reunited, the non-accelerated clock will read 6:00 while the other one might read 5:45?
Have such experiments been misreported, or misinterpreted?
1. What "point" is this author "trying to make?"
The the universe makes as much sense from Bob's point of view as from Alice's.
2. Does his "point" have anything whatsoever to do with physics,
As a physics lesson, I would expect that it is from the point of view of physics.
So, then, do you reject the reported empirical finds of such experiments as the Hafele-Keating one (and others reportedly confirming it, to greater accuracy) that clocks actually register less time when moving.
I fully accept the results of those experimetns. The clocks do indeed experience less time.
Have such experiments been misreported, or misinterpreted?
As far as I know, they have not been misreported. There are a variety of interpretations, as you well know, and they can not all be correct.
One Brow said "This is in contrast with the consequences of geocentrism are the loss of the principle of Conservation of Energy, but just for objects orbiting earth. In so doing, you toss homogenity out the door. When you do that, you no longer have a scientific position. Some positions can't be scientific, even if they can't be disproven. moral positions."
But how is it really "in contrast?" Along parallel lines, I can say:
"The consequences of advocating the torture of small children are the loss of the principle that human life has inherent value. In so doing, you toss humanity out the door. When you do that, you no longer have a moral position. Some positions can't be moral, even if they can't be disproven."
One Brow said: "The the universe makes as much sense from Bob's point of view as from Alice's...As a physics lesson, I would expect that it is from the point of view of physics."
Ya think? I say take it to the phychology class. It has nothing to do with physics. The universe makes as much sense to a delusional psychotic as it does to a normal person. So what? What does that have to do with physics?
We have already agreed, that Bob and/or the author, is WRONG in two ways:
1. Bob makes assumptions that are mistaken as a matter of phsyics (i.e., that he is motionless with respect to the earth, but that the earth is "really" moving), and
2. The author makes, and conveys assumptions about the scenario he creates, and then reverses those very assumptions when he claims "Bob is absolutely correct." Therefore the author is being blatantly inconsistent.
Is THAT supposed to be a good "physics lesson?" I can't see how.
1. "The clocks themselves are not affected by relativistic motion."
2. "I fully accept the results of those experimetns. The clocks do indeed experience less time."
Well, I don't think you are expressing yourself clearly. If the clocks actually give a different time reading, then they are, is some sense "affected." The clock, as a clock, is affected.
What "causes" this affect can be debated, but, the faster you accelerate a clock, the more it slows down (the less passage of time it registers), so you can't really say the clock isn't affected. It is.
We have aleady discussed the basic principles on which all clocks are based, regardless of construction, or type. You haven't indicated that we disagree on those principles, but maybe you do.
The "principles" I'm talking about are:
1. Device a way to count the number of (presumably) regularly recurring "instants" that accumulate, then
2. Correlate that raw number with a presumed "rate" of recurrence, then
3. Translate that into a measure of time elapsed.
Do clocks work in some different way, or on the basis of some different principles, as you see it?
Going back to our discussion from "way back when" about celsium clocks, it seems they work something like this:
Electrons will orbit the nucleus about 9 million times every second in a celsium atom (note that we must already have a definition for "second")
If we count, say, 18 million such orbits, then we will say two seconds have elapsed in duration from the time we counted the first such orbit until the time we counted the 18th million such orbit.
So we will construct a "read-out" display which tells us 2 seconds have passed every time our counter counts 18 million orbits. That is our "clock."
aintnuthin said...
In so doing, you toss humanity out the door.
Moral systems are not required to be humane. Many systems that people say they hold to are not.
We have already agreed, that Bob and/or the author, is WRONG in two ways
This agreement is based on assumed knowledge about Bob that is not present in the actual problem.
Well, I don't think you are expressing yourself clearly. If the clocks actually give a different time reading, then they are, is some sense "affected." The clock, as a clock, is affected.
Incorrect. Given your stated metaphysical assumptions, I do not think it is possible to get you to tsee this how I see it.
Do clocks work in some different way, or on the basis of some different principles, as you see it?
No.
Eric, you may well think I'm a smartass, but I know right now that you are headed into indefensible territory if you continue to make the inexplicable, ineffable assertions you have made about "time" in the past.
Your position is indefensible in terms of known and recognized physical prinicples, I mean. One can endlessly make vague mystical assertions, all while refusing to advance any type of physical explanation, and all without making even any apparent connection to, or compliance with, established principles of physics and physical laws, of course. Those with the "woo" mentality do it all the time. And, despite their inability to give any coherent, comprehensible explanation of their claims, it's still all "very obvious" to them.
Here's an excerpt from a paper I vaguely referred to before:
"...what we proved is that a [Lorentzian] theory is completely identical to special relativity: relativistic spatiotemporal conceptions + the relativity principle (governing the physics of moving objects). They are not only “empirically equivalent”, as sometimes claimed, but they are identical in all senses; they are identical physical theories.
Consequently, in comparison with the classical Galileo-invariant conceptions, special relativity theory tells us nothing new about the spatiotemporal features of the physical world. As we have seen, the longstanding belief that it does is the result of a simple but subversive terminological confusion."
http://philsci-archive.pitt.edu/5339/1/leszabo-lorein-preprint.pdf
The part I am stressing in this post is this: "Consequently, in comparison with the classical Galileo-invariant conceptions, special relativity theory tells us nothing new about the spatiotemporal features of the physical world."
This conclusion is preceded by 23 pages of rigorous analysis which you may, or may not, want to read.
Minkowski's "spacetime," however useful as a tool on geometrical analysis, can be just as easily applied to Newtonian mechanics and tells us "nothing new about the spatiotemporal features of the physical world," or so this author claims, and I agree with him. Einstein's postulation of SR did not suddenly reveal a new, previously undiscovered, aspect to the "physical reality" of space and time.
Did Minkowski come up with a novel way of conflating space and time for geometrical purposes? Probably. Did his invention of this formal novelty entail, require, or suggest a new PHYSICAl understanding of space and time? No.
A view other assertions made by this author:
1. According to this widespread view, special relativity was, first of all, a radically
new theory about space and time...in comparison with the pre-relativistic Galileo-invariant conceptions, special relativity tells us nothing new about the geometry of space-time.
2. Many believe that it is an essential difference between the two theories that relativistic deformations like the Lorentz–FitzGerald contraction and the time dilatation are real physical changes in the Lorentz theory, but there are no similar physical effects in special relativity....there is no difference between relativity theory and the four statements (18)–(21) are true in both theories. If, in the Lorentz theory, facts (18)–(19) provide enough reason to say that there is a real physical change, then the same facts provide enough reason to say the same thing in relativity theory....Thus, relativistic deformations are real physical deformations also in special relativity theory. One has to emphasize this fact because it is an important part of the physical content of relativity theory.
3. Putting all these facts together (see Schema 1), we must say that the null result of the Michelson–Morley experiment simultaneously confirms both, the classical rules of Galilean kinematics for xˆ and tˆ, and the Lorentzian kinematics for the space and time
tags x, t. It confirms the classical addition rule of velocities, on the one hand, and, on the other hand, it also confirms that velocity of light is the same in all frames of reference.
4. According to the conventionalist thesis, the Lorentz theory and Einstein’s special relativity are two alternative scientific theories which are equivalent on empirical level (see Friedman 1983, p. 293; Einstein 1983, p. 35)...there are no different theories; consequently there is no choice, based neither on internal nor on external aspects.
5. Due to the popular/textbook literature on relativity theory, there is a widespread aversion to a privileged reference frame. However, like it or not, there is a privileged reference frame in both special relativity and classical physics. It is the frame of reference in which the etalons are at rest. This privileged reference frame, however, has nothing to do with the concepts of “absolute rest” or the aether; it is not privileged by nature, but it is privileged by the trivial semantical convention providing meanings for the terms “distance” and “time...
6. Many of those, like Einstein himself (see Point 25), who admit the “empirical equivalence” of the Lorentz theory and special relativity argue that the latter is “incomparably more satisfactory” (Einstein) because it has no reference to the aether...I want to clarify that Lorentz’s aether hypothesis
is logically independent from the actual physical content of the Lorentz theory.
7. It is to be noted that our analysis is based on the following very weak operationalist/verificationist premise: physical terms, assigned to measurable physical quantities, have different meanings if they have different empirical definitions. This premise is one of the fundamental pre assumptions of Einstein’s 1905 paper and is widely accepted among physicists. Without clear empirical definition of the measurable physical quantities a physical theory cannot be empirically confirmable or disconfirmable.
As I said before, I am becoming more and more inclined toward the view that Einstien attempted to SR as a vehicle for importing an unwarranted and incompatible relationalist claims into "physics." His attempt to do so was characterized, first and foremost, by an ongoing tendency to equate raw perception with "truth." This led to a number of implicit inconsistencies. The "twin paradox" is just one case where the incompatibility of the philosophy with the physics becomes readily apparent.
A secondary philosophical approach he employed was based on the premise that any concepts without a physical referrent were metaphysical, fictitious, and meaningless.
Closely related to this was the epistemological claim that if we don't know the answer to a question, then there can be no answer (a thoroughly subjectivist viewpoint).
Mach, the relationalist, and Berkeley the radical empiricist, were his implicit mentors. Such views always end up in a radically subjective philsophy. This is ironic in light of the fact that they goal they are seeking is one of hard-headed, no-nonsense, "objective" truth which purportedly rejects all "subjectivity."
Unfortunately, his misguided philsophical premises, as well as the suspect solipsistic arguments he used to advance them, seem to have had more influence on theoretical physics than the physical contents of his theory.
I asked; "Do clocks work in some different way, or on the basis of some different principles, as you see it?"
You answered: "No."
OK, then, with that answer in mind, let me go back to the completely arbitrary example I used before when I said: "... if two clocks are synchronized to both read 5:00 and one is then accelerated, then, an "hour" later, once reunited, the non-accelerated clock will read 6:00 while the other one might read 5:45."
Let's look at this phenomenon in light of the basic principles on which we agree that clocks are constructed. For mathematical simplicity, let's say our standard "instant" occurs once per minute (on earth). And, again purely for reasons of simplicity which have nothing to do with "reality," let's say our "instant" is one full revolution of an electron around it's nucleus in a celsium atom. So, 1 revolution = one minute, OK?
Now our display reading is strictly the consequence of a mechanical counting process. It merely displays what it counts, and does not "adjust" it's counting because someone comes along and "tells" it to make adjustments to the numbers it actually counts.
Given that assumption, the moving clock will presumably have counted only 45 revolutions, while the stationary clock counted 60 revolutions.
How do explain this discrepancy in counting?
Did the speeding clock suddenly "miscount" what were actually 60 revolutions and report that number to be only 45? What happened to this clock?
If there were actually only 45 revolutions, and the clock correctly counted them as such, what happened within the "atom" whose revolutions were being counted? Did something called "time" order that atom to start revolving more slowly? In other words, did "time" simply reach in and "adjust" the operation of the clock, just like a watch-maker might do when adjusting the mechanisms of slow-running clock to make it report time accurately, only in reverse (i.e. in the way a watch-maker would adjust a properly-functioning watch if he wanted it to run slow, as part of some practical joke, or something)?
How would you explain the change in the clock's behavior after being accelerated?
Einstien said "Time is what clocks measure." In the particular example I used above, wouldn't it be more accurate to say that "revolutions of an electron are what a celsium clock measures?"
Or does a clock actually and literally measure "time itself" totally independently of how many electron revolutions occurred?
If a "true" minute passed, as determined by "time itself," would a celsium clock always then display the passage of one minute, whether it had counted 0 revolutions, 10 revolutions, 10 million revolutions, or whatever?
We have already agreed, that Bob and/or the author, is WRONG in two ways
One Brow said: This agreement is based on assumed knowledge about Bob that is not present in the actual problem.
How can you say that? You and I know it because the author told us, so he knows it too. Bob "knows" it too and/or has every obvious reason to know it. But suddenly the author acts like "Bob is correct" when Bob effectively denies what he knows to be true. The author praises Bob's "reasoning" when Bob's "reasoning" is obviously deficient. I don't get what you're trying to say.
A view other assertions made by this author:
How about these:
This privileged reference frame, however, has nothing to do with the concepts of “absolute rest” or the aether; it is not privileged by
nature, but it is privileged by the trivial semantical convention providing meanings for the terms “distance” and “time”; by the fact that of all possible measuring-rod-like and clock-like objects floating in the universe, we have chosen the ones floating together with the International Bureau of Weights and Measures in Paris.
...
Many of those, like Einstein himself (see Point 25), who admit the “empirical equivalence” of the Lorentz theory and special relativity argue that the latter is “incomparably more satisfactory” (Einstein) because it has no reference to the aether. As it is obvious from the previous sections, we did not make any reference to the aether in the logical reconstruction of the Lorentz theory. It is however a historic fact that, for example, Lorentz did.
Take the absolute reference frame and the ether out of Lorentzian relativity, and it sure does look a lot like SR.
Eric, you may well think I'm a smartass, but I know right now that you are headed into indefensible territory if you continue to make the inexplicable, ineffable assertions you have made about "time" in the past.
You mean assertions that don't comport with the vision of spacetime you have selected to comply with your preferecnces. I don't feel the need to be limited by your preferences, and never have.
Your position is indefensible in terms of known and recognized physical prinicples, I mean.
Name one.
One can endlessly make vague mystical assertions,
"Time is a dimension much like the spatial dimensions, and our actions have consequences on how we pass through it" -- mystical. "There is a medium that caries light, but can't be detected in any way except to match the predictions of the Lorentz equations, and concentrates around gravity fields even though it can't be detected by gravity" -- not mystical. Believe that if you want.
I have really enjoyed watching the projection here. The person who can't get around their preconceived notions of time and space was not Einstein nearly as much as it is you. It's natural, we all assume everyone thinks like us.
all while refusing to advance any type of physical explanation,
"Propulsion changes your passage through the dimension of time, just as it changes it through the dimension of space" is a physical explanation, just one that you don't accept for your own philosophical preferences.
How do explain this discrepancy in counting?
Did the speeding clock suddenly "miscount" what were actually 60 revolutions and report that number to be only 45?
No. There were only 45 revolutions to count.
What happened to this clock?
Nohting happened to the clock. Its passage through time was altered as its passage through space was altered. It's like asking what happened to the odometer on a car because you took Rte. 15 instead of State Street, and the odometer showed more miles to get to same point. The odomoeter just recorded more miles because you traveled a longer distance. The clock shows less time because it travgels through less time.
If there were actually only 45 revolutions, and the clock correctly counted them as such, what happened within the "atom" whose revolutions were being counted?
Nothing happened to the atom.
Did something called "time" order that atom to start revolving more slowly?
No.
In other words, did "time" simply reach in and "adjust" the operation of the clock, just like a watch-maker might do when adjusting the mechanisms of slow-running clock to make it report time accurately, only in reverse (i.e. in the way a watch-maker would adjust a properly-functioning watch if he wanted it to run slow, as part of some practical joke, or something)?
No.
How would you explain the change in the clock's behavior after being accelerated?
There is no changed behavior to explain.
Einstien said "Time is what clocks measure." In the particular example I used above, wouldn't it be more accurate to say that "revolutions of an electron are what a celsium clock measures?"
Yes.
Or does a clock actually and literally measure "time itself" totally independently of how many electron revolutions occurred?
No.
If a "true" minute passed, as determined by "time itself," would a celsium clock always then display the passage of one minute, whether it had counted 0 revolutions, 10 revolutions, 10 million revolutions, or whatever?
No one is claiming "time" controls anything.
How can you say that?
The author did not say Bob was originally in the same inertial frame as Alice, and then accelerated on the train. That is our assumption based upon our knowledge of people and trains.
I don't get what you're trying to say.
That our additonal knowledge allows us to call Alice right and Bob wrong.
One Brow said: "Nohting happened to the clock."
One Brow said: "Nothing happened to the atom."
One Brow said: "There is no changed behavior to explain."
One Brow said: "Propulsion changes your passage through the dimension of time, just as it changes it through the dimension of space."
OK, got it. Says it all.
One Brow said: "The author did not say Bob was originally in the same inertial frame as Alice, and then accelerated on the train. That is our assumption based upon our knowledge of people and trains."
The lengths you will go to to affirm totally fallacious claims amazes me, Eric.
One Brow said: "The author did not say Bob was originally in the same inertial frame as Alice, and then accelerated on the train."
The author didn't say he didn't either, did he? Oh, wait, my bad. Yes the author did say he didn't ever accelerate, indirectly.
In effect, he says:
"Bob does not think he ever got on a train. Bob thinks he is absolutely motionless, and that all the trees, houses, rocks, etc., which are attached to the earth are rushng past him.
Bob is absolutely correct!"
Since Bob is correct, then it follows that the girl, who thinks the train is moving, is wrong. Despite the delusions she has about not moving past the train, given that Bob is absolutely correct, she IS moving past the train.
Author: No, she is absolutely correct!
Got it. Says it all.
Once you deny the validity of the logical "law" of non-contradiction, you have tossed logic, and all possiblity of logical analysis, out the window. This is convenient, because now everything can be both true and false at the same time.
Every moral and scientific theory is now true (if you want it to be). Here's the great part, though:
Every moral and scientific theory is now false (if you want it to be).
Heads, I win; Tails, you lose, Sukka!
aintnuthin said...
The author didn't say he didn't either, did he?
True enough. If Bob and alice were real people, instead of illustrative constructs, that would even be relevant.
Once you deny the validity of the logical "law" of non-contradiction, you have tossed logic, and all possiblity of logical analysis, out the window.
First, there is no tossing of non-contradiction out the window.
Second, while it is not relevant here, you can create some simple, useful, interesting logics that do not contain non-contradiction.
One Brow said: "If Bob and alice were real people, instead of illustrative constructs, that would even be relevant."
C'mon, Eric, you've now given 5-6 weak-ass "reasons" for insisting this author is justified in saying "both are correct."
Are you suggesting that a physics professor is justified in presenting any old self-contradictory claim as "valid," so long as he's not using "real people" as examples in his illustrations?
One Brow said: "First, there is no tossing of non-contradiction out the window."
OK, whatever you say.
Bob thinks he is motionless and Alice is moving. He is correct.
Alice thinks she is motionless and Bob is moving. She is correct.
Therefore, we can justifiably conclude that both of the following statements are true.
1. Bob is moving, and Bob is motionless.
2. Alice is moving, and Alice is motionless.
It RULES when you don't violate the law of non-contradiction, eh?
I asked you this question a long time ago, and I have asked a number of similar questions which you don't bother responding to:
"One man's meat is another man's poison, they say. Protagoras said: "The same wind that feels cool to one man can feel warm to another. Therefore the same wind is both hot and cold."
Was Protagoras right? If so, in what sense what he right? Protagoras is obviously equating(as Einstein was prone to do) "what is perceived" with "what is" (real). Is this strictly the subjectivist view of reality the correct one, as Berkeley claims, ya think?"
I guess such questions don't really interest you, or don't seem significant enough to bother with, eh?
One Brow said: "...you can create some simple, useful, interesting logics that do not contain non-contradiction."
Yeah, I see people create that kinda *special* logic most every day, eh? Quite interesting, and very useful (for them).
Woooo.
Protagoras: Man is the measure of all things.
Socrates: Why man? Why not say pigs are the measure of all things?
Protagoras: Because you, Socrates, are a pig, and you aint knowwin nuthin.
Are you suggesting that a physics professor is justified in presenting any old self-contradictory claim as "valid," so long as he's not using "real people" as examples in his illustrations?
I'm saying the actual claim is not self-contradictory, although the interpretaion of the claim you are imposing on it is. The professor is making a claim about what can be detected empirically. Whether he means that as saying that emipircal truths are the principle truths or not, he has the empirical results accurate, as best I can determine. You want to add in additional ideas for who is correct that go beyond the empircal. I have no objection to that, but since the professor did not add them in, they don't factor into whether the professor is wrong in his statements.
I asked you this question a long time ago, and I have asked a number of similar questions which you don't bother responding to:
"One man's meat is another man's poison, they say. Protagoras said: "The same wind that feels cool to one man can feel warm to another. Therefore the same wind is both hot and cold."
Was Protagoras right? If so, in what sense what he right? Protagoras is obviously equating(as Einstein was prone to do) "what is perceived" with "what is" (real). Is this strictly the subjectivist view of reality the correct one, as Berkeley claims, ya think?"
You think that I believe there is a correct view of reality?
Is the heat of the wind determined by it's wind chill or by its effect on human appendages? If wind chill factor, the wind can't be both hot and cold. However, it can warm the hands of a man just out of a freezer yet cool the hands of a man just out of a steam bath. I think either of dicussing the effects fo the wind has merit.
One Brow said: "I'm saying the actual claim is not self-contradictory, although the interpretaion of the claim you are imposing on it is. The professor is making a claim about what can be detected empirically."
Wrong. A questioner, who was WELL AWARE of SR claims about what two people "see" asked this guy the question: Doesn't one have to be faster?
Per SR, the correct answer to that is "Yes, the one who has previously been (more) accelerated will be slower, and the other will be faster."
This guy's answer, in effect: "No, one doesn't have to be faster than the other. In fact each one is slower than the other."
That answer is wrong.
And self-contradictory, of course.
This guy, just like what seems to be thousands of other "experts,' seems utterly incapable of making any kind of distinction between subjective and objective reality.
The question rephrased: If both assume the other's clock is slower, doesn't one have to be wrong in his assumptions?
In other words, the questioner is, VERY SPECIFICALLY, asking if there doesn't have to be a difference between subjective and objective reality when two "subjects" see contradictory things.
This guy's answer: No, there doesn't. Self-contradiction is the order of the day with SR, and everything I'm telling you is 100% accurate as a matter of physical reality.
That's the kinda thing I had in mind when I said such things as:
"...Einstien attempted to SR as a vehicle for importing an unwarranted and incompatible relationalist claims into "physics." His attempt to do so was characterized, first and foremost, by an ongoing tendency to equate raw perception with "truth." ... Unfortunately, his misguided philsophical premises, as well as the suspect solipsistic arguments he used to advance them, seem to have had more influence on theoretical physics than the physical contents of his theory."
It seems that once these kinda guys are solemnly assured that some self-contradiction is "actually true" by a professor they trust, they will faithfully and thoughtlessly repeat it forever after.
This physicist is just all over the board about what "really is" happening, and he just can't consistently distinguish appearances from "reality."
For example, at one point he flatly states:
"If you were to run over to Alice at the moment that her stop watch reads 5 (using a TARDIS or something), she would say “right now my stopwatch reads ‘T=5′ and Bob’s reads ‘T=3.5′”. Also being clever, she realizes that this is because Bob’s clock is running slower, and she’s right."
Notice the last sentence: "She "realizes" that Bob's clock IS running slower." This presupposes that it really is running slower. This would be true if Bob, not her, was in fact the one who is moving, of course, any viewpoint where one can be considered to be "really moving" is a viewpoint to which he denies all validity. But, needless to say, he is NOT consistent about this.
He is called on this by a person who comments, and says:
"... Alice wouldn’t say that _Bob’s_ stopwatch read 3.5, she’d say that from *her point of view* a stopwatch on that train has only counted 3.5."
This reader is (properly) trying to keep a distinction between subjective perception and "objective reality." The reader is right.
So what does the physicist say in response? He refuses to acknowledge the distinction, but, instead, he now tries to equate Alice's view with "reality." He says:
"If you were moving like Alice (and so have the same moment planes) but happened to be where Bob is at T=5, then you could read his stopwatch directly, and it would definitely read 3.5."
"DEFINITELY read 3.5, eh? This is wrong. NOW he's saying that, IF you were in Bob's frame of reference, then, from his frame, you would see things exactly as Alice sees them from her frame. The whole idea behind the Lorentz transformations is that Bob will NOT "see" things in his frame the way Alice sees them in hers. If Alice "sees" the time elapsed in his frame as 3.5, then Bob will NOT "see" it as 3.5 in his. Again, this is just wrong.
In Bob's frame, when Alice's watch said 5, HIS would say 7, because, from his frame, her watch is running slower.
Notice that, when you say "in Bob's frame" you are really saying in the frame where it is assumed that Bob is not moving and that Alice is. Conversely, "Alice's frame" is the frame where you assume Alice is not moving, and that Bob is.
This type of eternal shifting from one point of view to another (while treating them the same), of shifting from the claim that "no one is right" to claims which imply one of the two is in fact right, etc., is so typical of these types of "edifying lectures."
As long as you never think straight, as long you never consistently distinguish between two contrasting viewpoints, as long as you keep shifting ground with your claims about what is "real," in short, as long as you equivocate at any point where it seems to help reach the conclusion you are determined to prove, then you can always "prove" both that A is A and that A is not A.
This is why the author I cited says such things as:
"Consequently, in comparison with the classical Galileo-invariant conceptions, special relativity theory tells us nothing new about the spatiotemporal features of the physical world. As we have seen, the longstanding belief that it does is the result of a simple but subversive terminological confusion."
"Subversive teminological confusion" he says. What I might simply call "equivocation."
I also find it amusing that this physicist refers his readers to a video clip which (he thinks) experimentally demonstrates his claim that: "there’s no physical way to say who’s moving and who’s not."
The clip he references is here: http://www.youtube.com/watch?v=akLC_JMjpjA
What's funny is that this is just the type of situation where you CAN tell if you're moving by virtue of whether or not you experience accelerative forces.
What's also amusing is that, in this clip, the body of the non-accelerating party "lurches" when the moving party accelerates, as though he had experienced an acceleration. This certainly enhances the "optical illusion" that is being perpetrated, but it hardly speaks well of the physicist's judgment to cite it as an "experiment." Even if it was a valid, non-doctored-up experiment, it would DISPROVE, not prove, his flat claim that "there’s no physical way to say who’s moving and who’s not."
As soon as you're about 5 seconds into the clip, it's very clear who is moving, and who isn't, thereby proving that there ARE means by which this issue can be decided.
This kind of "lecture" is simply typical, unthinking propaganda which attempts to persuade one to adopt an unwarranted "relationalist" philosophy about SR when, in fact, SR is incompatible with such a relationalist view.
Wrong. A questioner, who was WELL AWARE of SR claims about what two people "see" asked this guy the question: Doesn't one have to be faster?
Per SR, the correct answer to that is "Yes, the one who has previously been (more) accelerated will be slower, and the other will be faster."
Based on your philosophical preferences, this is the only answer you can give. I will make no further effort to change it.
This guy, just like what seems to be thousands of other "experts,' seems utterly incapable of making any kind of distinction between subjective and objective reality.
Objective, or absolute? Because the experince of both Alice and Bob are objective and empirical. It's not a matter of opinion, it's a matter of measurement. But I agree the answers don't fit in with an absolute reality.
One Brow said: "However, it can warm the hands of a man just out of a freezer yet cool the hands of a man just out of a steam bath. I think either of dicussing the effects fo the wind has merit."
Well, I agree there is some value to discussing such things too, if for no other reason than to understand what Protagoras claims are and whether they are accurate. But beyond that, it might help us to recognize what we, ourselves, or some other person, is really saying when similar claims are made.
Protagoras' claim brings up more than one interesting point, one being the relativity of pereception and further how context and perspective can create perceptual differences.
But how about an ontological point? Wheher a man just came out of a freezer or just came out of a suana, we are still talking about a human perception. Ultimately "where" is such a thing located? In the man, or in the wind? One should not carelessly impute what is in the man to what is in the wind.
Yet people arguing for a certain subjectivist view of relativity often want to impute the "man's perception" to the "wind itself." Like Protagoras, they want to impute subjective perception to objective reality and, in effect, claim that "Man is the meaure of all things."
Consider these two separate statements. Are they the same? Is there any meaningful distinction to be made between the two?
1. If Bob (1) assumes that he is motion, (2) assumes that two light beams originate at points that are equidistant from him and (3) assumes that each light beam travels at the same speed, then a conclusion that if he sees one first, then that one must have left it's point of origination first would be "logically correct," even if one or more of his premises were wrong. If one of his assumptions is incorrect, then his conclusion will be unsound, even though his "logic" is correct.
2. If Bob (1) assumes that he is motion, (2) assumes that two light beams originate at points that are equidistant from him and (3) assumes that each light beam travels at the same speed, then a conclusion that if he sees one first, then that one must have left it's point of origination first would be ABSOLUTELY correct as a matter of objective reality.
If they are not the same, should a good physics teacher make statement 2, when all he intends is statement 1? Should a good physics teacher even trouble himself with understanding the difference?
But how about an ontological point? Wheher a man just came out of a freezer or just came out of a suana, we are still talking about a human perception.
Science is more empirical than ontological, even if scientists occasionally for get that. Also, Bob's seing one lightning bolt before the other is not subjective, it's objective.
Yet people arguing for a certain subjectivist view of relativity often want to impute the "man's perception" to the "wind itself."
There can be different, objective poihnts of view. Objective means different people in the same positon would see the same thing, not necessarily that people in different positions see the same thing.
One Brow said: "Objective, or absolute? Because the experince of both Alice and Bob are objective and empirical. It's not a matter of opinion, it's a matter of measurement. But I agree the answers don't fit in with an absolute reality."
If a guy riding a train thinks he's not moving, "assumes" things about the speed of light, "measures" distance by making assumptions, etc., those are not strictly "empirical" experiences or empirical "observations." They are mental conclusions.
I said: "Per SR, the correct answer to that is "Yes, the one who has previously been (more) accelerated will be slower, and the other will be faster."
You responded: "Based on your philosophical preferences, this is the only answer you can give. I will make no further effort to change it."
If, as you are now saying more and more regularly, you think the conclusions about motion which are provided by SR are a matter of philosophy, then motion itself must be a matter of philosophy, like, for example, morality.
Or is it, as you often seem to claim, that YOU have no philosophical influences whatsoever and you discern raw, unadorned, uninterpreted facts to guide you as a matter of objective truth? Only those who fail to see the objective truth about the "path of time" are hampered by philosophy, whereas the enlightened ones, who have embraced the "path of time" can see raw, physical reality? So it not really a matter of philosophy at all. It's really that some idiots can't see the obvious truth, because THEY have a philsophy.
What is your "answer" to the question about whether one clock must be faster? Let me guess, you would, like this guy, reinterate what he's been told and say:
"there’s no physical way to say who’s moving and who’s not."
If he's right, then Al wasted his time on his theory, and no one should pay any attention to it or care in the least about "motion." It is indiscernable and beyond detection by means of methodological naturalism, like God. Only the mystics would have the answer about how and why things happen in the universe. The old physics, concerning with "matter in motion" was never anything more than a metaphysical pretense to know the unknowable--motion.
If this guy is right, each clock really is moving slower than the other. That's PHYSICAL REALITY, right there, not philosphy. Heh.
One Brow said: "Science is more empirical than ontological, even if scientists occasionally for get that. Also, Bob's seing one lightning bolt before the other is not subjective, it's objective."
I agree that the raw sense perception is "objective." The man who feels a wind does, generally, anyway, actually feel a wind. That said, neither the conclusions he draws about that perception nor the qualitative judgments he makes about how it "feels" (warm or cool) to him are "in the wind."
Bob "sees" one bolt first, that's objective. From that sensation, he "reasons" that they left their point of origination at different times. The "reasoning" in not "empirical."
The author I previously cited made this claim:
"Putting all these facts together (see Schema 1), we must say that the null result of the Michelson–Morley experiment simultaneously confirms both, the classical rules of Galilean kinematics for xˆ and tˆ, and the Lorentzian kinematics for the space and time tags x, t. It confirms the classical addition rule of velocities, on the one hand, and, on the other hand, it also confirms that velocity of light is the same in all frames of reference."
What does this mean? Well, I'm not 100% sure exactly what he intends by this claim, but I take it to be something like this:
1. First of all, the Michelson-Morley experiment presupposed that, if the earth was in motion around the sun, then the experiment they were conducting would reveal that motion. It would detect an "ether wind." I'm still not sure why they would make this assumption to begin with, but it is obviously based on other, underlying assumptions. On it's face, it just sounds like the old medieval arguments which were used to "prove" that the earth could NOT possibly be in motion, they said, because, if it was, we would feel a "wind."
2. But, did their failure to detect the ether wind prove that light was not subject to straight Galliean transformation (simple addition of velocities)? No, it didn't. Keep in mind that corrections for the sagnac effect are straightforward Galliean c + v or c - v. It simply "proved" that we cannot detect the ether, which implies that we cannot detect the speed of light relative to the ether. If we can't detect the speed of light, relative to the ether, then we can't know the speed from which we should add or subtract other motions in order to arrive at the speed in other (moving) frames of reference.
3. Once one "reasons" that it is the deformation of our measuring instruments that prevents us from measuring the motion of light accurately, then one can deduce the Galliean transformations that apply to light. Think of my example where, one hour later, we see a beam of light receding from an object moving at high speed at only .5 c.
4. It is simply a matter of adjusting for the real physical deformation that occurs, and then treating all measurements on a CONSISTENT, rather than on a "it varies frame-to-frame" basis.
5. So, in that sense, the Michelson-Morley experiment proved that the Galliean transformations DO apply to light, when uniformly measured.
As far as your "path of time" philosophy (whatever it is) goes, this author clearly denies what appears to be one of your basic premises about what SR tells us. He says:
"Thus, relativistic deformations are real physical deformations also in special relativity theory. One has to emphasize this fact because it is an important part of the physical content of relativity theory."
Obviously, he could be wrong. But if he is right, then the physical (not philosophical) content of SR itself implies that the "physical deformations" are "real," and that is an important part of the theory.
I kinda look at the "new-age" view of relativity, the "path of time" interpretation of SR, as giving the poor skeptical, "scientific," atheistic types the kind of "mystical" belief system, of the type that only the enlightened ones can comprehend, that they would otherwise be deprived of by trying to be "objective" and maintaining a "no-nonsense" attitude.
It's almost as good as religion as a vehicle for fulfilling the "need" for an inexplicable "spiritual" explanation of things. It allows physicists to thoroughly indulge the types of fantasies that subjectivism likes to generate.
My view is based, in no small part, on the lack of critical analysis they reveal when they readily accept and espouse the relationist views advocated by Al in their interpretation of SR when SR is, in content, incompatible with such views.
In reading relativists "explain" relativity, it is typical to encounter emphatic expressions of how "mind-blowing" relativity is. The claim is often made that one must be very sophisticated, very free from "prejudice," and must devote hours of cleansing himself from "superstition" in order to comprehend SR in it's full, world-shaking glory. Of course, only the select few are truly capable of comprehending this "radical" revelation about the "truth" of physical reality.
I said: "If this guy is right, each clock really is moving slower than the other. That's PHYSICAL REALITY, right there, not philosphy. Heh."
When I said "if this guy is right, then...," I didn't mean to imply that his (obviously mistaken) claim that "there’s no physical way to say who’s moving and who’s not" would imply that each clock is slower than the other. His claim would NOT imply that, even if it were actually true (which it aint).
The guy simply makes the raw claim that "each clock is slower than the other as a matter of physical reality," on the basis of assertion, not on the basis that it is entailed by anything else he refers to.
How, and why, does he, in effect, assert a claim that is blatantly self-contradictory? What leads him to such a point?
I assume your answer would be something along the lines of: There is no self-contradiction whatsover. The author understands that the "path of time" concept is objectively true, and that concept eliminates any and all otherwise-percieved self-contradictions, when properly understood.
If so, maybe you can explain to me exactly how the "path of time" approach, properly understood, would entail the conclusion that each clock is slower than the other.
If a guy riding a train thinks he's not moving, "assumes" things about the speed of light, "measures" distance by making assumptions, etc., those are not strictly "empirical" experiences or empirical "observations." They are mental conclusions.
I agree they are not strictly empirical observations. They are inductive leaps based upon empirical observations, the positions of homogeneity, etc. That doesn't make them subjective.
If, as you are now saying more and more regularly, you think the conclusions about motion which are provided by SR are a matter of philosophy, then motion itself must be a matter of philosophy, like, for example, morality.
I think the conclusions you are reaching about who is truly moving, who is really at rest, etc., are based in philosophical preferences that go beyond the relatively common set scientists take for granted.
Or is it, as you often seem to claim, that YOU have no philosophical influences whatsoever ...
If the assumption of a position is a philosophical preference/influence, than the refusal to accept that position is also a philosophical preference/influence. No fingerpointing or diminuation was intended.
What is your "answer" to the question about whether one clock must be faster?
Each clock moves at the same speed, relative to the amount of time it passes through. They only seem faster or slower compared clocks moving through time differently. Similar to the notion that if two cars travel at the same speed and different paths to the same location, one will often get there faster, but not because it had a different speed.
I agree that the raw sense perception is "objective." The man who feels a wind does, generally, anyway, actually feel a wind. That said, neither the conclusions he draws about that perception nor the qualitative judgments he makes about how it "feels" (warm or cool) to him are "in the wind."
I agree.
If we can't detect the speed of light, relative to the ether, then we can't know the speed from which we should add or subtract other motions in order to arrive at the speed in other (moving) frames of reference.
You mean, since we can't detect teh speed relative to ether, if it exists, we can't detect the speed at all?
As far as your "path of time" philosophy (whatever it is) goes, this author clearly denies what appears to be one of your basic premises about what SR tells us. He says:
"Thus, relativistic deformations are real physical deformations also in special relativity theory. One has to emphasize this fact because it is an important part of the physical content of relativity theory."
They are not real locally, only the observer in a different inertial environment. There is no disagreement here, just a different emphasis.
How, and why, does he, in effect, assert a claim that is blatantly self-contradictory? What leads him to such a point?
Each is correct in a specific inertial frame. Since the professor does not share your burden of the notion of an absolute frame, each position is equally valid.
If so, maybe you can explain to me exactly how the "path of time" approach, properly understood, would entail the conclusion that each clock is slower than the other.
That would entail the notion that there is no absolute frame from which to judge the clock movements. After that, it is a matter of something similar to perspective. Did you wan't/need more detail that?
I said: "What's also amusing is that, in this clip, the body of the non-accelerating party "lurches" when the moving party accelerates, as though he had experienced an acceleration. This certainly enhances the "optical illusion" that is being perpetrated, but it hardly speaks well of the physicist's judgment to cite it as an "experiment."
Notice also that the clip begins with the picture of an engine, sounding it's whistle, blowing steam, and presumably "all set to go." This is the engine which will presumably accelerate Van Kilmer in his passenger coach. This "steam" keeps streaming past him from a direction "front" of him as we anticipate that he is about to commence moving.
With the use of such"suggestive" gimmicks it is not hard to decieve a person who is viewing it from a remote, non-moving, two dimensional perspective. But who else would, like this physics professor, seem to think that optical illusions provide a valid experimental demonstration of what we can "say" about objective reality? Again, the equation of (mistaken) subjective perception with "reality" seems self-apparent. Well, self-apparent to those not enlightened by an understanding of the "path of time" concept, at least.
One Brow asked: "You mean, since we can't detect teh speed relative to ether, if it exists, we can't detect the speed at all?
No. What I meant was basically this. The expectation was that if light travels at 186,000 mps with respect to earth, then it would presumably (under Galliean transformations) be moving faster than that with respect to something "motionless," like maybe 200,000 mps. Then 200,000 mps could then be the "standard" for the speed of light. By comparison, the "speed of light" for something travelling at 50,000 mps with respect to the "ether" would then be 150,000 mps. And we could deem it to be that, even if, in that frame of reference, using the deformed rods and clocks in that reference, it might still be "measured" at 186,000.
In that case the 186,000 mps "as measured' would just be an artifact of the deformed measuring standards while the "true" speed would be 150,000 mps. In other words, the Gallean transformations could still be applied if you just stuck with one "standardized" set of rods and clocks, rather than change standards every time you changed reference frames.
That's what I think this author must be saying. SR does NOT preclude the use of Gallean transformations. It all just depends on what units of measurement you designate as "standard." It just a matter of making a distinction between "as measured in this particular frame" and "as measured by the "standard" units. Kinda like converting miles to kilometers, or vice versa, ya know?
One Brow said: "I think the conclusions you are reaching about who is truly moving, who is really at rest, etc., are based in philosophical preferences that go beyond the relatively common set scientists take for granted."
Well, all so-called "scientific" conclusions have a "philosophical" aspect to them, if you want to call it that. There are deductions, based on premises, in any "rational" conclusion. If I suggest, for example, that we can "tell" the earth is rotating, based on the behavior of a Foucault pendulum, I don't mean that the pendulum shouts at us: "Hey! Look at me! I'm staying steady while the earth rotates!"
I don't see my notions of motion as being particularly unique. If I see a horse running across the pasture, I simply say that it is moving and that I can "see" that it is moving (the "see" in in scare quotes there because there is still an element of assumption, and deduction therefrom, even in my "running horse" example).
It is a deduction, not an "empirical observation," that ultimately leads to that conclusion, even when it is based upon (starts with) an "objective" sense impression.
To complete the thought, Parmenides, as a matter of "philosophy" would argue that I do not, and can not" really see a horse moving because all such perceptions are "illusion."
As you (properly) observed, my rejection of the Parmenidean philosophy implies a different philosophy, and I DO reject his. Therefore, all my notions of change have a "philosophical" basis, because I believe, unlike Parmenides, that change "really" occurs.
But, again, I don't think my notions of movement, philosophy and all, are "unscientific." They could be, though. Why do you think that?
One Brow said: "Each is correct in a specific inertial frame. Since the professor does not share your burden of the notion of an absolute frame, each position is equally valid."
Well, we've been through this a dozen times, but again, the ultimate question is "equally valid" in what sense? As a matter or "physical reality?"
Can't be, at least not if SR is correct. In the sense that each of two men, one who judges the wind to be cool, and one which judges the same wind to be warm, are both "correct" (have equally valid subjective perceptions)? OK, I'll buy that second sense. I just wouldn't equate it with a sense that means "objectively real and valid as a matter of general physical laws."
If the professor accepts SR (again, I mean the physical content of SR, not the relationist philosophy) then he should readily accept the notion of a "preferred" (if not absolute) frame from which all motion, or lack thereof, is determined as a matter of "objective reality." SR does NOT hold that Bob and Alice are "both correct." If he's gunna purport to be an expert on SR, then he could at least give correct answers, I figure.
One Brow said: "That would entail the notion that there is no absolute frame from which to judge the clock movements. After that, it is a matter of something similar to perspective. Did you wan't/need more detail that?"
Well, yeah, I would like a little more detail. I have admittedly been a little snide about this concept, hoping to "provoke" you into an explanation.
I think I understand the lack of an "absolute frame" OK, and I think I have some appreciation of the role perspective can play in perception. But, even so, I really can't even begin to comprehend your claims about the (non) change in clock behavior. You indicated that this is because I do not apprehend the "path in time" concept, and, I admit, I do NOT understand it. I don't even understand what's intended by reference to it.
One Brow said: "That would entail the notion that there is no absolute frame from which to judge the clock movements."
I think it's worth keeping in mind that Newton, too, was well aware of the virtual "impossibility" of pinpointing an absolute frame of reference. He said, that, in theory, the point that was "motionless" with respect to all moving bodies, would be the center of gravity of the entire universe. But he made no pretense to being able to say just where that point was.
Hence all Newtonian mechanics is based upon a "preferred" frame, which makes no pretense to being "absolute." SR is no different in this respect.
It is really the philosophy of relationalism that wants to make the lack of an absolute frame an impenetrable stumbling block. In the background there is the demand for either (a) absolute truth or (b) no possibility of truth at all. It's kinda Platonic in that sense.
How does SR change things?
Let's go back to Bob on the train for a minute. The physicist who tries to "explain" this does a poor job in more ways than one, I think. One thing he just states, as a presupposed fact advanced without any elaboration on how that alters one's "calculations," is that the the speed of light is constant. So let's break it down a little.
We know that, from Alice's perspective, the two lightning beams are simultaneous, and also that she can also conclude that Bob will see the one from the front of the train first. The way she explains Bob's perception is due to the fact that (from her perspective) he is moving toward the flash coming from the front of the train. This, then, affects the "distance" each beam must travel to reach him. So the ultimate explanation really comes down to the "distance travelled" by each beam (which changes due to the motion of the train).
The ramification of all this for the nature of space (distance) and time? Nothing, really, at least nothing new.
But what if we assume that Bob "really is" motionless? How would we explain things if we assumed his subjective perceptions represented "objective reality?"
Well, to begin with, if he wasn't really moving, then he "really" would be at the midpoint between the two flashes, right? So now the question is: "Then why doesn't he "see" them at the same time?" Simplified answer, without math, is "because length (and time, which I'm ignoring right now) has changed in his frame."
So the transformations play the same role in SR as they did for Lorentz with respect to the (undetected) ether frame. The reason we can't "tell," by means of the Michelson-Morley experiment, that the earth is moving is because the rods and clocks have changed. In the same fashion, Bob (supposedly) can't "tell" that he's really moving because the etalons for time and distance have changed in his frame due to his (undetected) motion.
The premise for Lorentz is basically that: We know that we are moving, but can't detect it. The problem then becomes: "How do we explain our failure to detect motion?" The "answer" is given by time and distance distortion caused by a physical change in our rods and clocks.
This same premise, when applied to Bob, is essentially that Bob's knows he is moving, but can't detect it, so the same transformations apply to explain why he can't detect it.
So, to repeat, but stated another way the idea seems to be this:
1. "We" know Bob is moving, but he doesn't
2. Since he (purportedly) doesn't think he is moving, let's explain why he doesn't "think" he is moving, even though we know he is.
3. The explanation? That his rods and clocks have been distorted, relative to ours.
Of course if Bob "thinks" he is moving (rather than assumes that he isn't), everything changes. Now he no longer concludes that the beam of light from the front of the train "really" originated first. Now he concludes that he simply saw it that way BECAUSE he is moving, and realizes that he might well have seen the two simutaneously if he were NOT moving.
SR does NOT, in effect, assume that Bob is motionless. In effect it assumes that Bob is moving with respect to Alice's frame, but further assumes that "he doesn't know it" (even though "we" do). SR does not say "Bob is correct." It simply explains why he might think he is correct if he assumes that he is motionless, even though we know that he is NOT motionless.
Edit: These two sentences were intended to be the last paragraph, not the 3rd, in my last post:
The ramification of all this for the nature of space (distance) and time? Nothing, really, at least nothing new."
I said: "The premise for Lorentz is basically that: We know that we are moving, but can't detect it. The problem then becomes: "How do we explain our failure to detect motion?" The "answer" is given by time and distance distortion caused by a physical change in our rods and clocks."
By "time and distance distortion" here, it should be obvious that what is meant is that we arrive at a different "measure" of distance (leaving time aside) with "distorted' rods than we would have arrived at had our rods remained undistorted. FOR THIS REASON (rod distortion), we arrive at a different answer for "how long" a given distance is than we would have arrived at for the same distance if we were using undistorted rods. What we might have measured to be 100 yeards with an undistorted rod, we might now measure to be 110 yards with our distorted (shortened) rods. In other words, the EXACT SAME distance would be measured to be 100 yards with "proper" rods, but measured to be 110 yards with altered rods. The distance has not changed. The only thing that has changed is our measurement of that very same distance.
As an analogy, a meter is not the exact same length as a yard (although they are fairly close). If we measure THE SAME distance with a yardstick and then with a meterstick, we will get a different number of "sticklengths." But the distance itself has not changed. If we want to convert meters to yards, or yards to meters, it's fairly simple to do so. But the important thing to see here is that the choice of a meterstick over a yardstick does NOT change the distance measured. It just gives us a different number of sticklengths.
Let's assume one observer accelerates with respect to another to the point where the accelerated observer's rod have been shortened by 50%. We, with our unaltered rods, measure the distance between two stars (neither of which is moving with respect to the other) to be, say, 1 lightyear.
He will measure that same distance to be 2 lightyears. Is the distance between the two stars now BOTH 1 lightyear AND 2 lightyears? No, it is the same distance, however it is measured. If still another observer measures it to be 3 lightyears with (further) distorted rods, it is still the SAME DISTANCE.
Who's right? Well, let's forget that question for now because it's irrelevant to the point. All three may be wrong, but we know for sure that all 3 cannot be right. Whatever different observers might measure with rods which are distorted with respect to each other, the distance remains the same. 10 observers, all with different measurements would not change that. It's STIL the same distance. 20 different observers, 50 different observers, 100 different observers, it wouldn't matter. The distance between the two stars is still the same distance (assuming that the two are not moving with respect to each other).
"Space" (distance) does not change just because different observers use different lengths of sticks to measure it.
What I just said about space itself not changing is, according to the author I cited, critical to the theory of SR. He is right, I believe.
Does his claim have to be "true?" No, not absolutely, but he didn't claim it was "absolutely" true. He just said in was true within the theory of SR. If, as a matter of "true" physics, the distance between the two stars *actually* does change itself for every observer who measures it differently, then SR is simply WRONG, that's all.
In that case, a whole new theory must be devised to explain that, and SR must be chucked out the window as being hopelessly wrong.
If your claim is that space actually does change for each observer who happens to measure it differently, then I'm certainly curious to hear the details about how you have been able to utterly disprove SR.
That's what I think this author must be saying. SR does NOT preclude the use of Gallean transformations.
I flight travles in a universal ether field (as opposed to a locally inertial field) that can affect it's velocity, then the Michael-Morley experiment should have turned out differently, because light going back and forth with the ether would have a different travel time than light.
Let's say you have a uniformly flowing stream of water 1 mph, and that water waves move at exactly 5 mph. You set up a wave generator/detector, and a put a wave deflector 3 miles away. When you set this up perpendicular to the current, the current does not affect the speed of the wave. Moving at 5 mph, it takes 72 minutes for the wave to be detected. When you set this up parallel to the current, the waves move at 6 mph going to the target (30 minutes) and 4 mph on the way back (45 minues) for a total of 75 minutes. It will be out of phase.
Similarly, if you use Galilean relativity on a universally uniform ether field on which light travels, then Michael-Morleson will see light out of phase at somte point. Current LET responds to this by having ether collect in gravitational fields and share the inertia of those fieleds, but that has other problems.
But, again, I don't think my notions of movement, philosophy and all, are "unscientific." They could be, though. Why do you think that?
Phuilosphy is not a scientific enterprise (not even the philosophy of science), so all philosophy is ascientific. I said your preferences went beyond the set typically held in common by scientists. I suppose that means that in practice, you might see as settlesd some questions other scientists might see as needing an answer, but outside of that, I would not call it anti-scientific.
Well, we've been through this a dozen times, but again, the ultimate question is "equally valid" in what sense? As a matter or "physical reality?"
As a matter of objective, physical perspective.
I don't even understand what's intended by reference to it.
First, I want to clarify three different things with different names in space, that I beleive we both recognize as being different. There is something that is the physical separation of two objects, which I will call true distance. There is the measurement of this distance using a yardstick, or something similar, that our acceptance of isotropy says always measures off the same amount of true distance. I'll call that the measurement distance. Finally, there is the distance that we actually travel between the two locations, which can vary in size depending on the path we take. The is the path distance. We can measure the path distance using the same measuring device as we use for the true distance, and under isotropy, that means that we get a valid comparison of the true distance to the path distance.
Now, we can apply each of these concepts to time. There is something that is the physical separation of two events, which I will call true duration. There is the measurement of this distance using a clock, or something similar, that our acceptance of isotropy says always measures off the same amount of true duration. I'll call that the measurement duration. Finally, there is the duration that we actually travel between the two events, which can vary in size depending on the path we take. The is the path duration. We can measure the path duration using the same measuring device as we use for the true duration, and under isotropy, that means that we get a valid comparison of the true duration to the path duration.
For you, as far as I can tell, the true duration is always equal to the measurement durations is always equal to the path duration, and the true distance is always the measurement distance. I can see them as being different.
Before I talk about what this means for altered clocks and yardstick, is any of this confusing to you?
One Brow said: "Before I talk about what this means for altered clocks and yardstick, is any of this confusing to you?"
Well, yeah, it is. I basically understand what you're saying about distance, I think. I might interject a couple of qualifying phrases if I were trying to say it. I don't want to just nitpick but I do think it is obvious from some of my posts however, that I don't think a "yardstick" always measures "true" distance unless it remains unaltered, i.e., unless it is a "true yardstick." So I wouldn't agree to this claim in an unqualified manner: "There is the measurement of this distance using a yardstick, or something similar, that our acceptance of isotropy says always measures off the same amount of true distance."
I just think it's crucial to realize that "measurement of a distance" is distinct from the thing being measured. Just like a clock can run slow, a measurement device for distance can be miscalibrated. This is a distinction that some "positivists" want to deny.
It is the attempt to draw a strict parallel between time and distance with all of these same distinctions that loses me. The whole "path duration of time," analogy escapes me. It is easy to see that one can take a virtually infinite number of "paths" between two points in space.
But there seems to be a lot of reliance on mixed metaphors when one talks about different paths between two "points" in time. Granted, if I want to make dot on a page of paper, call it a point, and then say "THAT is a point in time," then I can still easily visualize an infinite number of paths between that "point" and any other "point" on any other place in the universe. But that is simply because each such "point" is still a "place" in space. It is NOT a point of time, and calling it that can't change what it is, which is a point in space, not a point in time.
I said: "But what if we assume that Bob "really is" motionless?...if he wasn't really moving, then he "really" would be at the midpoint between the two flashes, right? So now the question is: "Then why doesn't he "see" them at the same time?"
I meant to include something like this, at this point in that post:
One could say, well, then, the answer is obvious: If he truly is at the midpoint, and if the two beams do not reach him at the same time, then light simply does NOT, for whatever reason, travel at the "same speed" in both directions.
But that is not the answer given (because it has been conclusively presumed that the speed IS the same), so what's left? Well, short answer, distance (and/or time) changes for him.
The point is, one answer is no more obvious, prima facie, than the other, all postulation aside. IF the speed of light is constant THEN the distance and,or time MUST change, because speed is simply a quotient of distance/time. Conversely, if time/distance are constant, the speed must change.
Any "lack of certainty" about time, distance, simultaneity, etc. applies just as equally to any "certain" answer which Al gives to the question about the constant (one way) speed of light The "it's all a matter of perspective" approach ALSO applies to SR. Take a different perspective, and the constancy of light is simply false.
I asked: "Well, we've been through this a dozen times, but again, the ultimate question is "equally valid" in what sense? As a matter or "physical reality?"
You answered: "As a matter of objective, physical perspective."
Easy to say, but what do you mean by "objective physical perspective? Are you saying, for example, that is "equally valid" as a matter of physical fact (not just "perspective") to say that the horse which I "see" running is ACTUALLY motionless while I (and everything else I see as stationary) am moving as it is for me to say that the horse is running?
If you say "yes," that's what I mean, then there is no "physics" as any kind of intelligible subject of study. If you say "no," then why is it relevant to physics? Why keep bringing it up as something pertinent?
As a matter of linguistics, one might use a phrase such as "At that point in time...."
More literal would be the phrase "At that moment in time....."
But we all know what the guy means. A "point," by literal definition, refers to something like "a fixed location" and is something that exists "in space." Using the term "point" when referring to a moment in time is simply a non-literal, metaphorical type of useage.
Likewise, if I say "Al Jefferson is a tiger," no one thinks that I am saying that "Al Jefferson" is the name of some bengal tiger roaming the plains of asia. Nor do they think that I am trying to say that the person who people normally identify as "Al Jefferson" is, in reality, a tiger wearing a "human costume."
If someone said to me: "No, you just don't get it...Al Jefferson REALLY is a tiger...I mean, like, literally....no joke...He IS a tiger," I would just ask him if I could have some of whatever he had been smoking.
I would not "understand" what he was saying as being anything comprehensible.
I just think it's crucial to realize that "measurement of a distance" is distinct from the thing being measured. Just like a clock can run slow, a measurement device for distance can be miscalibrated. This is a distinction that some "positivists" want to deny.
I understand that you see this phenomenon behind the Lorentz equations.
It is the attempt to draw a strict parallel between time and distance with all of these same distinctions that loses me. The whole "path duration of time," analogy escapes me. It is easy to see that one can take a virtually infinite number of "paths" between two points in space.
But there seems to be a lot of reliance on mixed metaphors when one talks about different paths between two "points" in time.
That why I said that, for you, all three durations were always equal. I'm not trying to convince you of anything, just offering an explanation that you asked for, and checking to see if you understand the concept, even while disputing its reality.
Here's an example. Ship A takes off on a journey of length 24 light-hours, moving at .6c compared to the take-off point, and then stops. The take-off point calculates the journey as taking 40 hours, the ship experiences this as 32 hours. Following the same path in space and launching at the same time, ship B moves at .8c to the same location, then stops. Again, calculating from the rest frame of the take-off point, ship B requires 30 hours for the journey, but experiences only 18 hours. After they stop, they wait another ten hours for ship B, for a total of 28 experienced hours, versus the 32 for B.
Since they followed the same spatial path, the difference does not come from that. You would acribe this difference to altered clocks, biological functions, etc. I would ascribe it to traveling differently through time.
Easy to say, but what do you mean by "objective physical perspective? Are you saying, for example, that is "equally valid" as a matter of physical fact (not just "perspective") to say that the horse which I "see" running is ACTUALLY motionless while I (and everything else I see as stationary) am moving as it is for me to say that the horse is running?
That would violate physical principles like the conservation of energy.
If you say "no," then why is it relevant to physics? Why keep bringing it up as something pertinent?
Let me give you an analogy. We prove a few things in Geometry class before we introduce the Parallel Postulate, such as "Veritical angles are congruent". Any such proof is valid in non-Euclidean geometries. Knowing the principles from which a result comes helps you keep track of when that result will still be valid, should your principles need to change.
Knowing that the determination of whether the horse is moving or the earth comes from the conservation of energy, as opposed to relativity, means that if conservation of energy is ever overturned, we know whatever replaces it has to account for why the horse moves instead of the earth. However, if relativity is overturned, that would not affect our determinaiton that the horse moves instead fo the earth.
I just made a post quoting H. R. Brown that the spam filter apparently took, but it kinda relates to this too, as you can see once it is revitalized:
"You would acribe this difference to altered clocks, biological functions, etc. I would ascribe it to traveling differently through time."
Well, I simply say that if the number of orbits a celseum electron makes changes from 60 to 45 in the same amount of time then that physical process (orbiting) has slowed down (changed).
I don't pretend to know why (although Lorentz seemed to have a half-way decent explantion based on a theory of atomic processes). It just follows from what we know about clock construction and the principles upon which clock construction is based.
It is easy to glibly "ascribe" this change to some vague unspecified generalization like "traveling differently through time." But, in itself, such a statement is entirely devoid of meaningful physical content, and does not even address the changed behavior of the atom. To deny that the behavior has changed, when it has, does not enhance the consistency or comprehensibily of whatever claim is being made in my view.
There is no possible way to discuss the changed behavior if one denies it occurred. If I see a guy steal my wallet, tell him to give it back to me, and he simply claims he didn't steal it, all "discussion" is off. Time to kick some ass.
One Brow said: "Following the same path in space and launching at the same time, ship B moves at .8c to the same location, then stops. Again, calculating from the rest frame of the take-off point, ship B requires 30 hours for the journey, but experiences only 18 hours. After they stop, they wait another ten hours for ship B, for a total of 28 experienced hours, versus the 32 for B."
I haven't really tried to analyze this example (even though I should). I simply note that making comparisons back and forth between different frames with, in effect, different "definitions" of such terms as "hour," does not make much impression on me.
To me, each traveler "lands" when he lands, no question about it. He knows when he lands. How multiple other parties might "measure" the time at which he lands (or the duration of his flight) that can't change the undeniable tautology that "he lands when he lands."
The event must be "simultaneous" with itself. I will grant that the "slowing of clocks" ala Hafele-Keating is very mysterious. When time "slows down" for one party is time "different" for him? Absolutely! But, like I said, the earth will (presumably) still complete 10 revolutions of the sun in 10 years even if millions of objects across the universe are all travelling at millions of varying speeds with respect to us.
If some object, coming from an origination point from millions of lightyears, lands here, it will "land when it lands," for both us, and the object, however anyone else might "see it."
The physical 'reality" is that it lands when it lands. If, from some other perspective, it "seems" to land weeks before (or after) the time it actually meets with earth, those will just be false appearances, not matters of "physical reality."
aintnuthin said...
I just made a post quoting H. R. Brown that the spam filter apparently took,
Sorry, not this time.
Well, I simply say that if the number of orbits a celseum electron makes changes from 60 to 45 in the same amount of time then that physical process (orbiting) has slowed down (changed).
I understand and accept this is your position.
But, in itself, such a statement is entirely devoid of meaningful physical content, and does not even address the changed behavior of the atom.
Again, an analogy. We each get a basically identical car with basically identical tires. You go from 49th & State to 4th & State via 255 and 64, I just drive down State street. When we meet up, your odometer has more miles on it. I ask you why. You tell me you drove a longer distance. I tell you that such a statement is devoid of meaningful physical content, and does not even address the changed behavior of the odometer, because odometers should always show the same number of miles going from place to place. Do you think my objection is accurate, or indicates comprehension?
To deny that the behavior has changed, when it has, does not enhance the consistency or comprehensibily of whatever claim is being made in my view.
You mean, like I see you denying ther change in the behavior of the odometer in my example?
There is no possible way to discuss the changed behavior if one denies it occurred.
Even less so if there was no change.
The time at which I "become aware of" an event which happened in the past is irrelevant. The time of the occurrence is no different, even if it is "different for me" (in terms of when the "news" reaches me).
If I just learned yesterday that Lincoln was shot in April, 1865, that doesn't mean that it happened at a different time (yesterday) for me than it did for, say, a guy who just learned it a week ago, or from the time that it happened for J. W. Booth.
It is the failure to see such "subjective" differences are just that, merely subjective, that seems to confuse some people. They want to insist, in effect, that the time of Lincoln's death "really is" different for me. Perhaps they will just say that I took a "different path in time" than, say, Lincoln himself, to "explain" this difference, I don't know. If so, that would still not be the explanation.
One Brow said: "Again, an analogy. We each get a basically identical car with basically identical tires. You go from 49th & State to 4th & State via 255 and 64, I just drive down State street. When we meet up, your odometer has more miles on it. I ask you why. You tell me you drove a longer distance. I tell you that such a statement is devoid of meaningful physical content, and does not even address the changed behavior of the odometer, because odometers should always show the same number of miles going from place to place. Do you think my objection is accurate, or indicates comprehension?"
I've already answered this, I think. All you have to point out to me is that I travelled a longer distance, and that explains everything quite adequately.
That said, two "points" on a graph are NOT points in time, so the whole "path" analogy becomes senseless. Your implicit assumption is that time is, and can be treated as, identical to space. I can implicitly assume that apples are "identical" to oranges to "explain" why everything that is true about an apple MUST also be true of an orange.
It would be the assumption, not the logic, that I would question.
Al Jefferson is NOT a tiger (literally).
A point in time is NOT a point in space (literally).
Any pretense to the contrary does not change that.
Suppose you ask why the Lakers are ahead of the Jazz, and I answer "Because the Jazz are behind the Lakers."
Have I said anything that wasn't already implied in the question? Have I "explained" anything? Of course not.
I've already answered this, I think. All you have to point out to me is that I travelled a longer distance, and that explains everything quite adequately.
All the explanation I need to give for ship B is that it travelled through less time, and that explains everything adequately (with regard to why the clocks read 28 hours have passed instead of 32 for Ship B or 40 for the launch point). Now, just as you can further explain the various turns and changes you made in the traveling of a different distance, so I can further exlain the various twists that altered the directions of ships A and B through time. But the basic physical explanation is "wnet through less time", and it's no different than "went a longer distance", to me. Just as apples and oranges are both fruits, so time and distance happen to share this particular feature (they are indeed different in other ways).
I understand, and accept, you disagree.
Suppose I forget to wind my watch, and it stops. I ask you why. You say it stopped because it "experienced time differently" than a properly-working watch and therefore followed a different "path in time."
That might be your "answer" and your "explanation." Mine would be "Because you forgot to wind it, fool.
aintnuthin said...
Suppose I forget to wind my watch, and it stops. I ask you why. You say it stopped because it "experienced time differently" than a properly-working watch and therefore followed a different "path in time."
That might be your "answer" and your "explanation." Mine would be "Because you forgot to wind it, fool.
I suppose anything "might be" my answer. If you wanted my actual answer, it would be that energy was no longer being transferred from the spring to the hands because you forgot to wind it, fool.
Again, I'm not asking for your acceptance. If you don't understand the concept, I'll explain it further. If you understand and reject it, I will go on to explain why this affects lengths, as I see it.
One Brow said: "Sorry, not this time."
Heh, well, as much as I hatee to do it all again, I will recompose it.
H.R. Brown is a philosopher of physics at Oxford with a long-standing interest in the "ontology of spacetime." He wrote (among others) a book entitled "Physical Relativity. Space-time structure from a dynamical perspective (Oxford University Press), 2005."
Not long ago he also wrote (together with another Oxford philosopher of science, Oliver Pooley) an essay entitled: "Minkowski space-time: a glorious non-entity."
Non-entity, eh? What's that about? Well, their basic claim is that "Minkowski space-time cannot serve as the deep structure within a “constructive” version of the special theory of relativity, contrary to widespread opinion in the philosophical community."
They say that those who (like I take you to be doing) try to claim that Minkowski spacetime "explains" the length contraction and time dilation of SR are clearly putting the cart before the horse. An except:
"Talk of Lorentz covariance “reflecting the structure of space-time positedby the theory” and of “tracing the invariance to a common origin” needs to be fleshed out if we are to be given a genuine explanation... Otherwise
we simply have yet another analogue of Moliere’s dormative virtue...
What has been shown is that rods and clocks must behave in quite particular ways in order for the two postulates [of SR] to be true together. But this hardly amounts to an explanation of such behaviour. Rather things go he other way around. It is because rods and clocks behave as they do, in a way that is consistent with the relativity principle, that light is measured to have the same speed in each inertial frame."
http://philsci-archive.pitt.edu/1661/1/Minkowski.pdf
I agree with them. Minkowski's spacetime did not "cause" SR. On the contrary, SR caused Minkowski to devise a geometrical representation of the Lorentz equations (which Lorentz had already produced in full reliance on classical spacetime).
These authors also note that:
"[In 1949, Einstein was] articulating clear misgivings about key aspects of his 1905 principle theory approach...he warns against imagining that space-time intervals “are physical entities of a special type, intrinsically different from other variables (‘reducing physics to geometry’, etc.).”
Leave it to the mathematicians to try to "reduce physics to geometry" and then claim that geometry completely explains physical reality, eh?
One Brow said: "Again, I'm not asking for your acceptance. If you don't understand the concept, I'll explain it further. If you understand and reject it, I will go on to explain why this affects lengths, as I see it."
Well, I understand that you are equating time with distance in a way which I wouldn't. If you have a further explanation of why you make this equation, that would be nice also. But, either way, if you can explain why this affects lengths, I would be interested in hearing it.
I'm sure many people share H. R. Brown's thoughts on the matter.
Time for another analogy. You're looking at a some other guy's yardstick with the short edge being in the direction of your sight, so it looks like a flat rectangle of the long and medium sides. Someone turns it 30 degrees around the middle, so the long side looks shorter. You have a yardstick to compare it to, but yours doesn't swivel. So, if you measure the turned yeardstick along the long axis, you'll measure it to be less than a yard. Also, you can mesure a second face, made by the medium and short sides. When the other guy measures your yardstick, he'll also see your long edge as being shortened, but another edge as being longer.
When you are traveling in a different inertial frame from someone else, they are basically pointing away from you into time, and you are pointing away from them. You each see the other's yardstick as being shortended, and clock as running slower.
Well, Eric, a couple of comments/questions on your last post.
1. You said: "When you are traveling in a different inertial frame from someone else, they are basically pointing away from you into time..." See, here again, I find some of the assumptions underlying your descriptions puzzling. I can "point" east, or west. Those involve spatial dimensions. But how do I "point" with respect to time?
2. Everything in your explanation seems to revolve around how two different people, in two different frames, will "see" the other. OK, I get this. What I don't get is any explanation of "so what?" I can, and have, described how two different people can "see" the same object differently. My question has been, and still is: So what? What do the differing observations have to do with physical reality? Does it prove that "both are correct" in their subjective perceptions? If so, so what?
SR says that the guy who has been accelerated will "see" the situation from an erroneous perspective, and that the one who is has remained unaccelerated will see the situation as it "really is" (as between the two). It says that one guy is "right" and that the other is wrong, not that "both are correct."
What is the(physical, not psychological) relevance of the fact that each "sees" the other's yardsticks differently. Does that explain "why" one guy's has "really" contracted, and one guy's hasn't?
aintnuthin said...
But how do I "point" with respect to time?
By moving in a different inertial frame.
So what? What do the differing observations have to do with physical reality?
Each can describe an empirical reality. Physical reality goes beyond just science.
Does it prove that "both are correct" in their subjective perceptions? If so, so what?
Their perceptions are not subjective, they are objective within their inertial frame. As for both being correct, only in th4 sense that you can use either frame to get a consistent picture of the world.
What is the(physical, not psychological) relevance of the fact that each "sees" the other's yardsticks differently.
Time dilation became relevant for the GPS system. I don't know if length contraction is or will ever be relevant for anything.
Does that explain "why" one guy's has "really" contracted, and one guy's hasn't?
As far as I am concerned, neither yardstick has really contracted.
One final from me to you on LET. You are in a rest frame with respect to the ether. I come by you at .6c, so you see my clock slowed by a factor of .8 because the ether wind is slowing me down.
Why don't I see your clock as running faster?
One Brow said: "As far as I am concerned, neither yardstick has really contracted."
Well, OK, then! That quickly answers any and every question that could possibly be raised by the Lorentz contractions SR relies on. Like Phipps said, no theory is less frangible than one that relies on NOTHING!
One Brow said: "One final from me to you on LET. You are in a rest frame with respect to the ether. I come by you at .6c, so you see my clock slowed by a factor of .8 because the ether wind is slowing me down.
Why don't I see your clock as running faster?"
I thought it was clear, Eric, but I guess it never really is. All this talk about "seeing" other's clocks is metaphorical and probably literally impossible. In any event, what one "sees" is based upon what one assumes, and is ultimately based on deduction, not merely raw observation. Assuming you "notice" that my clocks are running slower, you will NOT assume that the ARE slower, because you will NOT assume that YOU are stationary. You will therefore not assume that you are unaffected by increased speed. You will assume that MY clocks are correct, and then deduce that it is, in fact, YOUR clocks that are "really" running slow, while mine are correct. Using the Lorentz equations, you can then "correct" your clocks and determine what the "correct" time-keeping says.
aintnuthin said...
Well, OK, then! That quickly answers any and every question that could possibly be raised by the Lorentz contractions SR relies on. Like Phipps said, no theory is less frangible than one that relies on NOTHING!
Identifying that a question is moot, because it is based on a false premise, is a legitimate answer.
I thought it was clear, Eric, but I guess it never really is. All this talk about "seeing" other's clocks is metaphorical and probably literally impossible. In any event, what one "sees" is based upon what one assumes, and is ultimately based on deduction, not merely raw observation.
So the answer is irrelevant because it would never happen in real life.
Assuming you "notice" that my clocks are running slower, ...
Why would I notice them running slower, as opposed to faster? My clocks are supposedly being slowed by ether, but what is up with yours?
One Brow said: "Time dilation became relevant for the GPS system."
Now that you mention GPS, keep in mind that it demonstrates many of the points I've been making (about assumptions and measurements, for example).
Recall that, for operational purposes, the GPS system relies on a "preferred" non-rotating ECI frame as the standard for "absolute" time, just as LR would do.
With the GPS, the ECI is the ONLY frame in which the speed of light is "constant," because all other clocks, on the satellites, monitoring stations, etc. are moving with respect to the ECI. Light is calculated to travel at varying speeds relative to cities on earth, travellers on roads, etc., because (1) they are moving with respect to the ECI, and (2) because the satellite clocks are preadjusted to be synchronized with the "universal" time kept by the ECI clock. The clock on a satellite will always read the same as a clock in the ECI, despite the fact that it is moving.
This proves nothing about whether LR (or SR) is correct, but it does show that clock synchronization and calculation of the "speed of light" is merely conventional. Different assumptions and/or different methods used by LR simply result in different "calculations," that work just as well (or in the case of the GPS system, better) in practice than SR.
One Brow said: "Why would I notice them running slower, as opposed to faster? My clocks are supposedly being slowed by ether, but what is up with yours?"
What gives you the idea that the "ether" is slowing clocks in LR? It is increased speed, not the ether, which slows clocks down. That is true for either SR or LR.
One Brow said: "Identifying that a question is moot, because it is based on a false premise, is a legitimate answer."
Got it. Says it all.
There is no length contraction or time dilation. Kinda funny that Al can somehow force the Lorentz equations to work under such circumstances, but, hey, he's a genius, ya know
Recall that, for operational purposes, the GPS system relies on a "preferred" non-rotating ECI frame as the standard for "absolute" time, just as LR would do.
What other type of preferred frame would have been a better choice?
Different assumptions and/or different methods used by LR simply result in different "calculations," that work just as well (or in the case of the GPS system, better) in practice than SR.
Since the calculations of SR and LR match perfectly, as you have told me many times, how are they now different?
What gives you the idea that the "ether" is slowing clocks in LR?
That was the explanation on one of the meta-research links. Compression of molecules by passing through the ether.
It is increased speed, not the ether, which slows clocks down. That is true for either SR or LR.
Why should speed slow down time? What's the mechanism?
Kinda funny that Al can somehow force the Lorentz equations to work under such circumstances, but, hey, he's a genius, ya know
Indeed.
One Brow said: "So the answer is irrelevant because it would never happen in real life."
No that is not the answer. Nor is it the one I gave.
One Brow said: "That was the explanation on one of the meta-research links. Compression of molecules by passing through the ether."
As I said before, I'm not really conversant with the particulars of any particular theory, but I suspect that the "compression of molecules" portion is probably meant to explain length contraction generally, whereas the "ether" (gravity) within the earth's immediate vicinity may be used to explain why we don't detect motion.
One Brow asked: "Why should speed slow down time? What's the mechanism?"
Good question. One I've asked you. You're all over the lot, Eric, and completely inconsistent.
THERE MUST be length contraction and/or time dilation for it to even be theoretically possible for the speed of light to be measured as equal in all inertial frames. THAT'S WHY Al had to incorporated "transformations" for time and distance in his "theory."
You seem willing to flatly repudiate any and/or all aspects of SR theory if it suits your claims about what happens, and what doesn't. Whether it "happens" or not, the theory presupposes that it does.
The question of "why" it happens is a separate one, but the answer is NOT that it "doesn't happen." If it doesn't happen, SR is just plain WRONG.
I said: "The clock on a satellite will always read the same as a clock in the ECI, despite the fact that it is moving."
Which helps demonstrate the point that there is no "necessary" reason why either observer must "see" the other's as moving any differently. It's simply a matter of converting (via the Lorentz transformations) from one "system" to the other, and setting your clock accordingly.
One Brow said: "Since the calculations of SR and LR match perfectly, as you have told me many times, how are they now different?"
The predictions are the same, the calculations are different, but only in the sense that the assumptions are different and therefore give you different numerical answers. The form of the calculation remains the same.
As I have said many times:
1. IF the speed of light is to remain constant in all initial frames, THEN time, distance, or both MUST change.
2. If time and distance do not change, then the speed of light MUST change.
If you keep the same time, then the speed of light changes. So you calculate a different "number" for the speed of light in LR, even though you are using the same conversion formulas. GPS does this, because it keeps time (not speed of light) constant between frames.
You might want to ponder how this fact affects your claims along the lines of "nothing happens to the clock, nothing happens to the atom," etc.
Once you start making those claims, it is impossible to discuss anything with you so long as you continue to say SR is correct. It is just a blatant inconsistency to try to maintain both positions.
Back to the original issue, moral theory vs scientific theory, and the role of subjective preference (as opposed to objective "necessity") in each. This author articulates two views of SR, one which he calls "naive" and one which he calls "sophisticated:"
1. "According to the most "naive" physics textbooks, the emergence of Einstein's special relativity is one of the usual scientic discoveriesof new facts of nature. Certain experimental findings necessitate us to draw the conclusion that the geometry of space-time is something different from what we believed before, that, contrary to what we thought before, the speed of light is the same in all inertial frame of reference, that the transformation rules of the space and time tags belonging to different inertial frames are not the Galilean transformations, as it was believed before, but the Lorentz transformations, that, contrary to the classical views, the concept of distance, duration, and simultaneity are not invariant, but they are reference-frame-dependent concepts.
2. According to a more sophisticated approach, popular among philosophers of physics, experimental findings do not imply special relativity theory alone, but they imply either special relativity or its contemporary rival Lorentz theory...[which]remains completely within the framework of the Galilei invariant classical theory of space and time. So, according to this view, the switch to the relativistic theory of space-time is a convention, rather than an unambiguous theoretical conclusion drawn from the empirical facts."
http://philosophy.elte.hu/leszabo/Preprints/twoessays.pdf
Which view do you adhere to, Eric? If 2, then how can SR be "empirically" superior to LR any more than a pro-abortion moral stance can be "empirically" superior to an anti-abortion moral stance?
View number 1: "...contrary to the classical views, the concept of distance, duration, and simultaneity are not invariant, but they are reference-frame-dependent concepts."
View number 2: "...the Galilei invariant classical theory of space and time." Put another way: Our concepts of distance, duration, and simultaniety are INvariant.
How did Newton define our "concept" of time? Like this:
"Absolute, true, and mathematical time, in and of itself and of its own nature, without reference to anything external, flows uniformly and by another name is called duration. Relative, apparent, and common time is any sensible and external measure (precise or imprecise) of duration by means of motion; such a measure - for example, an hour, a day, a month, a year - is commonly used instead of true time." -Principia
Like Liebnitz and the relationalists, Newton did not consider either time or space to be real "substances." But he is not talking about a substance here, he is talking about a concept, which is merely an abstaction which we (conceptually) create.
Our "concept" of time is NOT frame-dependent, and a change of frames therefore cannot alter our "concept." It can alter the frame, but not the concept, which is itself wholly independent of frames.
It is only if one starts thinking that "time" is a thing, a physical subtance, that he can even begin to challenge Newton's claim. If time is NOT a concept, but is instead a physical substance, then it goes without saying that Newton has misconceived the nature of time.
Newton makes a clear distinction between time as a concept (true time) and time as sensibly and externally measured (relative, apparent, and common time). In other words, for Newton, the "measurement" of time is not "time itself" (which is an invariant concept).
The attempt to deny any such distinction (logical positivism with a "verificationalist" definition of meaning) is itself a "philosophy" that has been discredited due to inherent inconsistencies and self-contradiction. Einstien later realized this, and abandoned his early positivism. The change in his philosophical position is apparent in some of the quotes of his that I have previously posted (e.g., the one where he says Newton's "absolute space' equals Lorentz's "ether" which equals SR's "spacetime interval" and where he concludes that space is, in fact, something "real" even if not something "subtantial."
If you are interested in subscribing to the positivistic philosophy, Eric, I would recommend that you first read up on it, it's rise and fall, during the first half of the 20th century, and also see the basis upon which it was ultimately rejected as a viable philosophy.
http://library.thinkquest.org/06aug/02088/newton.htm
At this site, there is an interesting superimposition of an erratic, irregular orbit over a perfectly symmetrical and circular one representing the earth's orbit around the sun.
The "perfect" one is based on "apparent, relative" time, as measured, and based upon the (once-common) assumption that the duration of every rotation of the earth is equal. The irregular orbit represents the "correction" of common (apparent, relative) time, by an appeal to "true" or "absolute time."
The two are different, and the difference is indeed "meaningful."
I said: "1. IF the speed of light is to remain constant in all initial frames, THEN time, distance, or both MUST change.
2. If time and distance do not change, then the speed of light MUST change.
If you keep the same time, then the speed of light changes. So you calculate a different "number" for the speed of light in LR, even though you are using the same conversion formulas. GPS does this, because it keeps time (not speed of light) constant between frames."
http://library.thinkquest.org/06aug/02088/newton.htm
At the very bottom of this page is a five minute video clip explaining just how Einstein "reconciled" the claim of the constancy of the speed of light with time and distance. Like our physicist friend, this video starts with the unquestioned assumption that the speed of light is constant.
As a consequence of that assumption, he makes time and distance change. This clip reviews (with pictures) just what what we have already talked about at some length with respect to the "Bob" on the train. It should be obvious that one only need assert that time and distance (being concepts) do not change and the "reconciliation" is that the speed of light changes.
The "reconciliation" I was talking about was this: How do we reconcile
1. The empirical fact that the guy on the spaceship "sees" the light coming from the front on his ship first, with
2. The assumption that time and distance do not vary and that he is midway between the front and back of the ship?
But, actually, the "speed" of light" does not have to change. The whole "discrepancy" can just as easily be eliminated by recognizing that he is moving, rather than assuming that he is stationary. Once we recognize that, then we EXPECT him to see the light from the front of the ship first, IF the speed of light is constant.
When we use this this method of reconciliation, then the implications are that:
Neither "true time" nor "true distance" really change (they can't, because they are concepts which don't change with speed), but, as a result of motion, "apparent" time and "apparent" distance change due to a deformation of the rods and clocks. This fact ends up giving a distorted measurement of true time and true distance. This is where Newton's distinction between true time (conceptual) and relative time (as measured by gauging motion) explains (reconciles) things.
I cited this source:
http://library.thinkquest.org/06aug/02088/newton.htm
To get to the video I was referring to, you have to:
1. First click on "Go back to what is time." That will take you to another page where there is a pictue of a clock with several names on it, including "Einstien." Then...
2. Click on "Einstien." That will take you to yet another page. It is at the bottom of THAT page where the video I was referring to can be found.
I don't know how to get directly to this page by using a direct link.
I said: "If you are interested in subscribing to the positivistic philosophy, Eric, I would recommend that you first read up on it, it's rise and fall, during the first half of the 20th century, and also see the basis upon which it was ultimately rejected as a viable philosophy."
Heh, just for the hell of it, I looked up wiki's entry on "logical positivism." It ends as follows:
"Most philosophers consider logical positivism to be, as John Passmore expressed it, "dead, or as dead as a philosophical movement ever becomes." [16] By the late 1970s, its ideas were so generally recognized to be seriously defective that one of its own chief proponents, A. J. Ayer, could say in a interview: "I suppose the most important [defect]...was that nearly all of it was false."
Another commentary on the sorry fate of positivism, eh?:
[Logical positivism profoundly affected the whole of analytical philosophy, and mixed itself in with the foundations of modern physics, Einstein, Bohr and Born being sympathsizers and occasional attenders of conferences organized by the movement.
In the end the combined talents of all the Postivists and their associates (not exactly trifling) were quite defeated, and I don't think verificationism has a single living defender. This "justly famous episode of black comedy in the history of philosophy", as David Stove calls it, played out..."
http://cscs.umich.edu/~crshalizi/notabene/logical-positivism.html
The typical relativist that I have seen:
1. Undertakes to spout slogans and conclusions stemming from a philosophy that is incompatible with SR,
2. Claims that he is merely elucidating the scientifically "proven" postulates of SR, and therefore
3. Implicitly contradicts himself freely and frequently, and then
4. Tells anyone who points out his inconsistencies that they are scientifically ignorant, and mentally incapable of understanding indisputable science, but sympathizes that
5. Their mystification of time and space is indeed extremely difficult for the unenlightened to comprehend. They then suggest that their listeners would do well to spend some time cleansing themselves of all naive notions which prevent them from comprehending and accepting the (self-contradictory) claims of the relativist as the proven truths that they are.
As I said before, I'm not really conversant with the particulars of any particular theory, but I suspect that the "compression of molecules" portion is probably meant to explain length contraction generally, whereas the "ether" (gravity) within the earth's immediate vicinity may be used to explain why we don't detect motion.
I thought is was also the explanation for time differential.
Good question. One I've asked you. You're all over the lot, Eric, and completely inconsistent.
On the occasions when I have expressed my understanding, it has been that different intertial frams pass through time differently.
You seem willing to flatly repudiate any and/or all aspects of SR theory if it suits your claims about what happens, and what doesn't. Whether it "happens" or not, the theory presupposes that it does.
I flatly reject some of the interpretatiobns you bring to SR. The time dilation and length compression are real in that same sense that when you see a yardstick at an angle, it looks shorter.
Which helps demonstrate the point that there is no "necessary" reason why either observer must "see" the other's as moving any differently. It's simply a matter of converting (via the Lorentz transformations) from one "system" to the other, and setting your clock accordingly.
If the GPS clocks didn't see the earth's clocks as running slower, they wouldn't need to have been slowed down.
Once you start making those claims, it is impossible to discuss anything with you so long as you continue to say SR is correct. It is just a blatant inconsistency to try to maintain both positions.
You see an inconsistency where none exists.
Which view do you adhere to, Eric? If 2, then how can SR be "empirically" superior to LR any more than a pro-abortion moral stance can be "empirically" superior to an anti-abortion moral stance?
If all the experiements so gfar can not tell the difference, then the difference is not empircally based, nor do I recall claiming that it was. Rather, Lorentz theory strikes me as not credible for the unlikely properties the ether assumes, and SR is preferable because it narturally leads to GR.
Still, there should be a fairly easy test for LET. Have a really fast observer on a plane compare a clock in the plane to a clock on the ground. If your understanding of LET is correct, the clock on the ground will run faster, not slower.
Our "concept" of time is NOT frame-dependent, and a change of frames therefore cannot alter our "concept." It can alter the frame, but not the concept, which is itself wholly independent of frames.
I agree.
One Brow said: "You see an inconsistency where none exists."
I see an obvious inconsistency where one obviously exists.
One Brow said: "The time dilation and length compression are real in that same sense that when you see a yardstick at an angle, it looks shorter."
Is it real, or aint it? I don't give a rat's ass how something "looks." Does SR use a non-imaginary, non-illusory length contraction and time dilation to compute at it's results, or not?
One Brow said: "On the occasions when I have expressed my understanding, it has been that different intertial frams pass through time differently."
Heh, Eric, stop with the vague mumbo jumbo and THINK for a minute, eh? Now you have "inertial frames" passing "through time?"
Now you have hypostatized and reified not one, but TWO abstract concepts. I aint seen no "inertial frames" buyin nobody drinks down at Red's Road House, know what I'm sayin?
One Brow said: "If the GPS clocks didn't see the earth's clocks as running slower, they wouldn't need to have been slowed down."
Actually, it is the satillite clocks which are "speeded up" while the earth clock remains unaltered. But you just can't seem to make a clear distinction between "seeing" something and understanding what's behind (which may be quite different from the "appearance." Here, once the clocks are synchrozied to the ECI, then all the clocks used "show" the same time. Therefore, there is no difference to "see," although there is definitely a difference (which has been adjusted for as far as the clock "readout" goes) in the rate at which physical processes (such as atomic orbits of an electron) recur.
The point is simply what I said it was...a simple correction and you will "see" no difference, even if there is a real, underlying but unseen, one.
The broader point is that there is no reason to ASSUME that you are at rest at all times. As used by the proponents of SR, this is exactly what a "frame of reference" is. It is not a frame of reference which YOU are in UNLESS you assume you are not moving. If I ride a horse, and don't assume that everything is moving past me and the horse while we remain motionless, then, per SR advocates I am in somebody else frame of reference, not my own. An unnecessary, arbitrary, and unreasonable way to define it, needless to say.
One Brow said: "SR is preferable because it narturally leads to GR."
Heh, SR does not "naturally" lead to GR. Al sweated over GR for 10 years, with God only know how many false starts, and how many trials and errors of different field equations, fundamental concepts, etc. In the end, he had to dump fundamental postulates of SR (constant speed of light) to get GR to work.
Who told you that SR "naturally" leads to GR?
I asked: "If 2, then how can SR be "empirically" superior to LR any more than a pro-abortion moral stance can be "empirically" superior to an anti-abortion moral stance?"
You didn't really respond to the question when you said this:
"Rather, Lorentz theory strikes me as not credible for the unlikely properties the ether assumes, and SR is preferable because it narturally leads to GR."
Yeah, and I prefer the anti-abortion stance because Bush told me to think that way. But the question was about an empirical contrast, not a personal preference, eh?
As far as this part goes "Lorentz theory strikes me as not credible for the unlikely properties the ether assumes..." It's like a thief condemning theft. SR is faced with the exact same problems of explaining a mechanism...but it just refuses to address such questions (an aspect of SR which Al greatly regreted in later life).
Saying "they don't exist" is pure wishful thinking, where you impute limitations to your opponents which fully apply to your theory, too, but instead of acknowledging and facing that, you stick your head in the sand and deny the existence of a problem in order to "resolve" it.
Cheap and easy. Too cheap. Too easy.
Suppose I gave you a 24" "ruler" calibrated to read 12." After I give it to you, I tell you what I've done. To reinforce the point, I hold up a regular, 12" ruler, next to yours. We both agree that mine is shorter.
Now suppose you go walking down the street, and, God forbid, can no longer compare your 24" ruler with a standard ruler. Now what!?
Will you completely forget that your ruler is miscalibrated to read one foot when every standard ruler reads two feet?
Will distance "shrink" for you? When you measure a 300 foot-long football field to be only 150,' will you tell yourself that it "really is" only 150 feet, because that's what you just measured?
What kinda clown would do that? You may "see" only 150 feet, but you will NOT conclude that is "really is" only 150 feet long. Well, unless maybe you're some kinda mentally handicapped soul, know what I'm sayin?
I see an obvious inconsistency where one obviously exists.
I accept your position as being determined, and have no inclination to change it.
Is it real, or aint it?
When you look at a yardstick at an angle, is the shortness from the veiwing angle real?
Does SR use a non-imaginary, non-illusory length contraction and time dilation to compute at it's results, or not?
Can something based in perspective be non-illusory and non-imaginary?
I'll let you answer those questions for yourself.
Now you have hypostatized and reified not one, but TWO abstract concepts.
I accept your correct. It would have been better to say "On the occasions when I have expressed my understanding, it has been thatobjects in different intertial frames pass through time differently."
Actually, it is the satillite clocks which are "speeded up" while the earth clock remains unaltered.
Yes, once they are in orbit they speed up to keep pace with the clocks on earth. Sorry if that was unclear in my phrasing.
Heh, SR does not "naturally" lead to GR. Al sweated over GR for 10 years, ...
"Naturally" =/= "easily".
In the end, he had to dump fundamental postulates of SR (constant speed of light) to get GR to work.
Even in SR, the speed of light changes according to its environment. No postulate was dumped.
Who told you that SR "naturally" leads to GR?
We've gone over the basic postulates before.
You didn't really respond to the question ...
I felt "... the difference is not empircally based, nor do I recall claiming that it was." to be a sufficient response.
It is not the least bit surprising that, after pages of trying to tell me that scientific theories are really just preconceptions of the scientists that cram empirical data inside of it, you have chosen a theory that fits your preconceptions of what distance and time are, and are happy to stuff all the data inside of it, since those preconceptions see other notions as being contradictory. Good for you.
I see nothing contradictory in the notion of moving differently in time (not quite in the same manner you can move differently in space), and noting what some of the effects of those movements are. I can go on repeating that used a yardstick twisted in a different direction will of course measure things differently, not because the yardstick is wrong, but because you are not measuring things straight-on, but it seems it will fall on deaf ears. Such is life.
I'm not signing off the conversation, and I will continue to read and respond as I see fit. I just wanted to get that off my chest.
One Brow said: "When you look at a yardstick at an angle, is the shortness from the veiwing angle real?"
We've been over the notion of optical illusions, and the difference between objective and subjective "reality" hundreds of times, and you're still asking questions like this?
If I look at a yardstick from angle, does it "really" become less than 3 feet long? Answer: no.
If a physicist does an "experiment" and is thereby temporarily deceived into thinking that a party is moving when he isn't, was the guy he was watching "really" moving so long as the physicist was deceived? Answer: No.
Do you think otherwise?
One Brow said: "I see nothing contradictory in the notion of moving differently in time (not quite in the same manner you can move differently in space)..."
Your metaphors are not reality, Eric. One does "move" through time, one moves through space. Time will continue to flow, even if you are absolutely motionless. All this talk about "travelling paths through time," etc., is just poetic license, unless you can explain what it means, as opposed to simply making rhetorical assertions that are hollow at bottom.
Poetic symbolism, playing on language, is for mystics. Physics deals in objective reality, not subjective imagination and wordplay.
Think about it, Eric...Finally, after all this talk, you are now trying to claim that there IS NO length contraction/time dilation in SR. Tell me, then, when the travelling twin returns, why isn't he the exact same age as his stay at home brother?
Why don't they both have a good laugh about how they were mutally deceived into thinking the other was aging slower, when, in fact, they are identical ages?
Many, like Dingle, have said this (no "real" age difference) was the necessary consequence of SR, and you seem to agree with him.
Dingle was right, insofar as that would be the only acceptable conclusion from a relationalist viewpoint. But Dingle made the mistake of taking all the completely bogus "relationalist" rhetoric about SR promulgated by advocates of SR (including Al) who were trying to cram that philosophy into SR, when SR rejects it. You seem to be making the same mistake as Dingle, except you are not as consistent as him. If you were, you too would insist that SR CAN'T be correct.
One Brow said: "I accept your position as being determined, and have no inclination to change it."
Just like you, when you insisted the odds were 2:1 against, when they were 50/50, way back when. NOTHING anybody could say could get you to understand your mistake and re-evaluate your claims.
You're right, I will not change my position just because you continue to insist that an erroneous claim is true. You would have to give a credible explanation of your claims for me to do that.
I have, over and over again, pointed out the flaws in your position. You never address them head-on, you just reject them, out of hand, as being a product of my blind stupidity. And, of course, you continue to insist that your vague, ill-considered, and unexplained assertions to the contrary are true.
As Russell once said (paraphrasing: "Asserting, rather than demonstrating, has all the advantages that stealing has over honest labor."
One Brow said: "Can something based in perspective be non-illusory and non-imaginary?"
Somethng "based in perspective" will be EXCLUDED from any and all mathematical formulas which strive to represent objective, physical, reality.
Al would have left all calculations of length contraction and time dilation out of his formula they were merely "based in perspective." Perceptual psychology might strive to explain the dynamics underlying questions of illusion and subjectivity, but physics doesn't.
I said: "You seem to be making the same mistake as Dingle, except you are not as consistent as him."
Just to be extra-clear about the "mistake" I am talking about:
SR purports to be (and is) a physical theory. It provides (without any "explanation" whatsoever) mathematical formulas which are used to predict actual (not subjective) physical outcomes. In that sense, it just is what it is. There is no "philosophy" involved in it.
Even so, certain "interpreters" of SR try to import certain claims, maxims, and assertions of a philosophical nature into SR. Nothing wrong with that, per se, but if the philosophy is utterly inconsistent with the predictions of SR as a physical theory, then the philosophical claims about what SR "says" are simply wrong.
Dingle treated the misguided and mistaken philosphical assertions about SR, made by those of the logical positivist persuasion, to be primary, and to be the "substance" of the theory. This was his mistake. He (correctly) said that, IF the philosophy being espoused is correct, the SR CAN"T be correct. He was right about that, but he was wrong in treating SR as a matter of "philosophy," because it isn't. It is a physical theory, and the imputation of false philosophical notions to SR can't change the physics of it.
You too have substituted the conclusions which would follow from an incompatible philosophical stance into SR, and claim that those philosophical conclusions MUST give you the same answer about "reality" as SR does. But SR does NOT reach the same conclusions as the philosophy would dictate.
If you want to cling to your philosophy, then REJECT SR. On the other hand, if you want to cling to the physical predictions of SR, then REJECT your (incompatible) philosophy.
One or the other. You can't consistently have both.
We've been over the notion of optical illusions,
The change in appearance form a change in perspective is an optical illusion? That I can measure .7 yards for a yardstick in a specific direction, when the yardstick does not point in that direction, is an illusion? The yeardstick extends a yard in every direction at all times, and I'm just misinterpreting it to extend .7 yards in a specific direction?
... you're still asking questions like this?
I'm still unsure of your answer, frankly.
If I look at a yardstick from angle, does it "really" become less than 3 feet long? Answer: no.
Now, could you answer the question I posed, instead of some other question about what "really" happens to the yeardstick?
Answer: No.
Do you think otherwise?
No, but you didn't answer my question.
Your metaphors are not reality, Eric.
As I have mentioned, I don't expect you to see this as being more than a metaphor. I see it as a description of reality.
... unless you can explain what it means, ...
It's a fairly fundamental concept, so I can't break it down into smaller concepts. I have given you a couple of analogies for similar concepts, but can't really improve on that. I accept I will not convince you.
Think about it, Eric...Finally, after all this talk, you are now trying to claim that there IS NO length contraction/time dilation in SR.
More precisely, it is not a local phenomenon. The clock seen as moving slower is not actually slowed.
Tell me, then, when the travelling twin returns, why isn't he the exact same age as his stay at home brother?
Because he passed through less time on his journey.
NOTHING anybody could say could get you to understand your mistake and re-evaluate your claims.
In our discussions over the years, you have caused me to re-evaluate several claims, occasionally even resulting in a change of opinion. I don't know if you can say the same about me, I don't recall you acknowledging such. It just happens that in this case, reagrding this claim, your position relies on a philosophical need for an absolute concept of time that I don't share.
IYou never address them head-on, you just reject them, out of hand, as being a product of my blind stupidity.
I certainly don't think you hold your positions out of stupidity, nor blindness.
Somethng "based in perspective" will be EXCLUDED from any and all mathematical formulas which strive to represent objective, physical, reality.
Isn't the length of a shadow based on teh perspective of the light source to the pole whose shadow is seen? Do you think we exclude such perspective when calculating the length of the shadow?
Perceptual psychology ...
When I use perspective, I am referring to something closer to "The appearance of objects in depth as perceived by normal binocular vision". No psychology involved.
You too have substituted the conclusions which would follow from an incompatible philosophical stance into SR,
Incompatible with what, beside your vision of reality? It's certainly quite compatible with SR.
One Brow said: "Now, could you answer the question I posed, instead of some other question about what "really" happens to the yeardstick?"
I've answered your question a million times. As I walk away from a man who is 6 feet tall, the farther I walk, the "smaller" he gets in my perception.
Is my perception real? Yes, as purely subjective matter. Is it "true" (i.e., does the man "really" get smaller and smaller as I walk away)? No, it is false from an objective standpoint.
You can't seem to fathom any difference between subjectivity and objectivity, which, of course, goes a long way toward explaining all the confusion you display.
One Brow said: "Because he passed through less time on his journey."
Yeah, right, and it is the "dormative quality" of opium that make you sleepy, eh?
But, the point is, that the age difference is NOT merely illusory, and not merely the product of (deceptive) subjective perception. AGING really does slow down. Are you still claiming that "real" age differences result from an "illusory" slowing of physical processes?
Are you still saying that there IS no length contaction and/or time dilation?
Please take your pick, and stop with the blatant inconsistencies.
One Brow said: "When I use perspective, I am referring to something closer to "The appearance of objects in depth as perceived by normal binocular vision". No psychology involved."
You just showed that you don't know the difference between physics and psychology either. "Appearance" is not physical reality.
Physics may well end up explaining why certain appearances and subjective perceptions (such as the subjective appearance and conclusion that the "earth does not move") are false, but that is not it's subject matter.
The subject matter of physics is to explain the underlying, objective reality about matter in motion, not the psychology of human perception.
Preface: Spam filter just ate one or more of my posts (including one about math);
One Brow said: "... your position relies on a philosophical need for an absolute concept of time that I don't share."
You, or I, can have any subjective view about "time" that we choose, just like you are free to believe in any God (or lack thereof) that you choose to. That is not, and has never been, my ultimate point here, as I have repeatedly pointed out.
I am talking about SR, it foundations, premises, and content. SR could well be completely WRONG. I am not arguing that it is right or wrong. I am simply discussing what it says, and what claims are consistent/inconsistent with it.
At bottom, SR relies on an "absolute" concept of time, whether you like it, or agree with it, or not. If you reject that notion, then reject SR. Don't distort and mispresent SR to make it comply with your notions. Just reject it, be consistent, and be done with it.
I said: "Don't distort and mispresent SR to make it comply with your notions. Just reject it, be consistent, and be done with it."
As Mach, and every other self-consistent relationist, did, ya know?
Dingle, like Mach, and like you, to the extent you hold any kind of coherent position, was a relationalist at bottom. For years he extolled the virtues of SR.
Then, at some point, it hit him--SR is NOT consistent with relationalism. So, he said, SR in NOT consistent!
Dingle was a very intelligent man, yet he did not, for many years, understand that, despite all the in-vogue claims to the contrary, SR was NOT relationalist in either conception or predictions. Some, less intelligent, may NEVER see that, once they have bought into the false claims that SR actually IS a relationalist theory of relative motion.
Dingle was wrong. SR is internally consistent, it is simply not consistent with the logical positivistic relational philosophy held by Mach (and Dingle).
It is, instead, consistent with abolutist notions of space and time.
One Brow said: "On the occasions when I have expressed my understanding, it has been thatobjects in different intertial frames pass through time differently."
That rephrasing wouldn't change my response in the least. Objects are not "in" inertial frames. They may be "in space," but an "inertial frame" is merely a mental concept, which refers to a particular observer.
Like I said before, I am not IN an inertial frame when I am riding a horse. SR tells me that, if I don't assume I am motionless, then I am not "in" the inertial frame where I am located (i.e., on the back of a moving horse). In that case, I am "in" the "inertial frame" of the earth (but only if I assume the earth is also motionless). If I don't assume that anything is motionless, then I can't be in any inertial frame.
The existence of an inertial frame is completely dependent upon my subjective, mental assumptions about what is (or is not) moving, and it is not something which exists apart from my arbitrary assumptions.
Your whole claim here is reminiscient of the one where the guy claimed that gravity is due to "time pointing downward." It disregards all matters of actual phsyics, and assumes that mathematical conceptions are what "cause" physical events. This is precisely the type of "analysis" that Einstein warned against.
There is nothing wrong with the concept of an inertial frame, don't get me wrong. The concept is basically a necessary element of making any statement at all about motion. Newton relied on it, Einstein relied on it, and so does anyone else (at least implicity) who tries to make any claim whatsover about motion.
The only point I'm making is that objects do not exist "in" inertial frames, and that an inertial frame is not something "physical," but rather mental and conceptual.
As such, inertial frames cannot physically "cause" length contraction or time dilation. They cannot make a clock slow down, or a yardstick get shorter.
Compressed atoms or temperature changes at least "can" (not saying they do, in every particular case), in theory, cause and explain length contraction and the slowing of physical processes in rods, clocks, and other things.
Inertial frames cannot, in principle. They are not physical things (like atoms) which can have different levels of "agitation," compactness, speed, etc.
One Brow said: "Isn't the length of a shadow based on teh perspective of the light source to the pole whose shadow is seen? Do you think we exclude such perspective when calculating the length of the shadow?"
I don't even know what you're trying to say here. I may measure the length of the shadow made by a pole to be 37 feet at 6:00 A.M and only 2 feet at high noon.
Either way, I measure it with a tape measure. Different people doing the same thing will NOT (in the absence of error) get different measurements.
If some physicist/mathematician wants to reduce the measurement I get in each case to a mathematical formula, he can do so (based upon the angle of inclination, etc). But his formula will neither determine nor alter the distance I measure. The tape measure does that.
One Brow said: "The clock seen as moving slower is not actually slowed."
You should systematically revise physics and present your theory to guys doing Hafele-Keating type of experiments. Those guys take two identical clocks, reading the exact same times, then send one into space at increased speeds. When it comes back, the clock has "actually" slowed, or so they say. If you are right, they are completely deluded, and I'm sure they would be interested in knowing just how they are completely misled by their sense impressions. Your "new physics" theory could no doubt enlighten them.
I like clocks. I have eight of them on one shelf. For the most part, they are highly reliable. Day in, day out, the all say 7:00 at the same time and, an hour later they all say 8:00 at the same time. But one day, last year, they all said 7:00 at one time, but an hour later, only 7 of the 8 read 8:00. The other one read 7:45. And here I thought the explanation was that the one clock "actually slowed." This assumption was shared by my clock maker, who told me it was running slow, made an adjustment, and its been keeping time with the other 7 ever since.
Kinda surprising how wrong you can be. Turns out, the clock never "actually slowed," I guess. Go figure, eh?
Preface: Spam filter just ate one or more of my posts (including one about math);
Sorry, didn't see them in the spam filter.
"Appearance" is not physical reality.
Fine, then instead of "perspective", let's call it "angle of incidence". I see an angle of incidence is a real thing with real effects. For example, when you hold a yardstick so the long side is parallel to the sun's rays, it casts a smaller shadow then when the shortest side is parallel to the sun's rays. Even though the yardstick doesn't change, there is a real change in the shadow. I've been calling that perspective, but you seem to be getting hung up on the word, so I'll try using a different phrase to express the idea.
Let me make this perfectly clear: as long as you are answering based on something subjective, and not objective, you are not answering my question. Can you see the difference between objective and absolute? For example, the yardstick casts a shadow objectively, but there is no absolutely correct version of the shadow, because it changes with the angle of incidence?
So, is the change in appearance from a change in angle of incidence an illusion? In particular, if you think it is an illusion, how can such a change make a measurable change in an object's shadow?
Yeah, right, and it is the "dormative quality" of opium that make you sleepy, eh?
Going back to the example of taking two different routes from point A to point B, when you come up with a more explanatory reason for different odometer readings depending on the path chosen than "went a different distance", I'll agree that there is a better explanation than I provided. Until then, I don't see the need to distinguish the "dormative quality" of different durations for different paths in time any more than different distances for different paths in space.
Are you still claiming that "real" age differences result from an "illusory" slowing of physical processes?
Since I never made that claim in the past and am not making it now, I can hardly be "still claiming" it.
Are you still saying that there IS no length contaction and/or time dilation?
I am saying there is no change to the yardstick/clock. Length contraction/time dilation is a result of path, not instrument.
At bottom, SR relies on an "absolute" concept of time, whether you like it, or agree with it, or not.
At bottom, this characterization of SR is wrong, whether you like it, or agree with it, or not.
Dingle was wrong. SR is internally consistent, it is simply not consistent with the logical positivistic relational philosophy held by Mach (and Dingle).
It is, instead, consistent with abolutist notions of space and time.
It's also consistent with non-relational, non-absoluist notions of time and space.
They may be "in space," but an "inertial frame" is merely a mental concept, which refers to a particular observer.
If acceleration is an absolute quantity, then teh lack of acceleration (an inertial frame) is also an absolute quantity, not merely a mental concept.
As such, inertial frames cannot physically "cause" length contraction or time dilation. They cannot make a clock slow down, or a yardstick get shorter.
I agree, which is why I have not claimed that they do.
aintnuthin said...
You should systematically revise physics and present your theory to guys doing Hafele-Keating type of experiments.
My explanation is actually quite consistent with those results.
Hey, I forgot something..who's to say that the one clock "actually slowed" to begin with? It's possible that the other 7 all just speeded up, aint it? No one can ever say for sure which one happened...every clock in the world could have speeded up, and they would all agree...they would just be wrong, that's all.
But, wait...that can't be right either. Since these kinda things can't be known with absolute certainty, you can't even say the 7 were wrong. There is only one conclusion, I guess, to wit:
All the clocks are right. There can be no "correct" answer. All the clocks in the world that say 8:00 are correct. So is the one clock which says 7:45. Yeah, that's the ticket!
One Brow said: "At bottom, this characterization of SR is wrong, whether you like it, or agree with it, or not."
I have already quoted a bunch of experts saying it is correct. Not that you would have actually read/understood any of them, I guess.
Like poor Dingle, you seem incapable of distinguishing the philosophical propaganda about what SR "says" from what it's formulas and conclusions say. The propaganda is right, the theory is wrong, except, of course, it's not wrong because...well, because the propaganda is right and it says SR agrees with it.
Spacetime intervals in SR are "absolute." They have to be. You must have some immutable standard(s), which do(es) not change, willy-nilly every second, in order to arrive at ANY reliable prediction, about anything.
SR could not possibly conclude that one twin "actually" ages more (or less) than another without standards.
Here the standard is set by the preferred frame. Length contraction and time dilation are NOT the result of relative motion between two objects. They are the result of absolute acceleration with respect to the preferred frame of reference chosen by SR.
Both observers may "see" the other's clock as being slower (and these perceptions, considered in isolation, WOULD be the result of relative motion alone). But they will not both actually BE slower, because it is NOT caused by "relative" motion, but rather by absolute motion.
That means one is "seeing" an illusion, and the other is "seeing" things as they really are. It is only the clocks of the guy who has accelerated which have "really" slowed in SR, while those of the stationary observer have not changed in the least. That is because he remains in the preferred frame which sets the "absolute" standard (which doesn't change).
In SR, the stationary observer is RIGHT when he says the traveller's clock slows down. On the other hand, the accelerated observer is simply WRONG when he claims the other's clock have slowed down.
I've only pointed this out (myself, and by way of quoting experts) about a hundred times. If you still don't get it, you never will. The effect of over-exposure to propaganda at an impressionable age can be virtually impossible to overcome, I guess.
One Brow said: "I am saying there is no change to the yardstick/clock. Length contraction/time dilation is a result of path, not instrument."
Eric, can't you see that you contradict yourself in this very sentence? You're like the lawyer defending a client accused of damaging a borrowed vase, who said: "First, I will prove that my client never borrowed the vase. Secondly, I will prove that the vase was already cracked when he borrowed it. Finally, I will prove that my client returned it in perfect shape."
The question is NOT about what "causes" the effects (i.e., what it "results" from, be it path in time, or whatever). The question is about whether these effects occur to begin with. First you deny they occur, then you "explain" why they do in fact occur.
First: "I am saying there is no change to the yardstick/clock." Here you are saying there is no length contraction or time dilation.
Then: "Length contraction/time dilation is a result of path, not instrument." How could something which never happened to begin with "result" from anything?
Your thinking is quite confused, I'm afraid.
One Brow said: "If acceleration is an absolute quantity, then teh lack of acceleration (an inertial frame) is also an absolute quantity, not merely a mental concept."
Don't confuse an "inertial state of motion" with an "inertial frame of reference." One is talking about actual motion. The other is simply talking about a "perspective" from which motion is viewed. Even assuming that an object could "move" through "time," a frame of reference cannot. An object has physical reality. A frame of reference does not. An object can have "inertial motion," a frame of reference cannot have any "motion." It's not that kinda thing.
Speaking of inertial "states of motion," that too is something to be posited. For Newton (and for Al in SR) the moon was NOT in a state of inertial motion (it was accelerated). In GR, it is in an inertial state of motion (unaccelerated). Which one is an empirical fact? In which type of "inertial frame" would the frame "cause" time dilation?
One Brow said: "Can you see the difference between objective and absolute? For example, the yardstick casts a shadow objectively, but there is no absolutely correct version of the shadow, because it changes with the angle of incidence?"
If by "absolute" you mean the platonic notion of something immutable, eternal, and absolutely correct in ALL circumstances, sure, I can see the difference. If you want to say that nothing is "absolute" (well, apart from a priori concepts used in formal systems such as math and geometry) in the platonic sense, then I would certainly agree with you.
Every single observation, mental (which we usually call conclusions) or physical (sense perception) is AlWAYS conditional and made with reference to a particular perspective. It is nothing unique to SR.
But physics does NOT concern itself with making an exhausting catalogue of subjective perceptions of a infinite number. It does not try list how long Patui would measure the length of a shadow at 6:01 A.M. on December 27th in Punjab, India, then list what he would see at 6;02 A.M. and, eventually list what Eric would see at 4:07 P.M. on June 8th in St. Louis, Missouri, etc.
Physics in not concerned with the particulars of individual perception. It is concerned with principles, based upon PHYSICAL, not mental, phenomena. It does not have a separate set of "laws" for what you see if your vision is 20/20, and another set for what you would see if your vision was 20/30, etc. That is not its subject matter.
The relationalists (who call themselves relativists) want to make subjective perceptions (rather than objective physical occurences) the very basis for the laws of physics. That approach is misguided. NO science ever does that, physics, or any other science. No "rational" thought of any kind does it.
One Brow said: "So, is the change in appearance from a change in angle of incidence an illusion."
No, it is not an illusion. The length of the perceived shadow has in fact changed, and the reason for the change can be explained completely apart from whether the "observer" is blind or not. It is not based upon subjective perception (or lack thereof). It is based on an actual distance measured, which does not vary from person to person. The reason for the changed distance can be (and is) explained without any regard whatsoever to the idiosyncratic circumstances of any observer.
I said:"In SR, the stationary observer is RIGHT when he says the traveller's clock slows down. On the other hand, the accelerated observer is simply WRONG when he claims the other's clock have slowed down."
But, as I've also pointed out many times, no intelligent accelerated observer, familiar with the laws of SR, would EVER conclude that the stationary clocks have "slowed down," while his hasn't. He would realize that HIS clocks slowed down, and further realize that the stationary clocks had not changed.
Nor would you conclude that a regulation-sized football field is "really" only 50 yards long if I sent you out walking with what you knew to be a two-foot long "ruler."
In the same way, a guy who bought a train ticket would NOT reasonably conclude that a light beam from the front actually occurred before one from the rear, just because he "saw" the one from the front first.
All these claims about what an accelerated observer "sees" are based upon the knowledge that he is accelerated, and he is therefore moving. We know that, and, unless he is an utter dumbass, he knows it too (that he is moving).
You would "see" or "measure" only 50 yards with the distorted rod, but you what not conclude that what you measured or saw was "correct."
What SR says if that IF you accelerate, then, and only then, your clock will actually slow down, and that this "fact of nature" holds true whether you know it, or accurately perceive it, or not.
If you don't accelerate, it won't happen. If someone else accelerates, then THEIR clocks, not yours, will slow down.
The mystics want to say that both are correct; that both mutually exclusive possibilities "actually occur." If that's their true belief, then they should vehemently deny all the predictions of SR, rather than adopt it as something which they say "proves" their non-sensical "theory."
Not that you would have actually read/understood any of them, I guess.
Of course, it's not possible that you've misunderstood any of them, I suppose.
You must have some immutable standard(s), which do(es) not change, ...
All you need a consistent standard for a problem to be able to solve that problem. It does not need to be any sort of absolute standard.
SR could not possibly conclude that one twin "actually" ages more (or less) than another without standards.
However, it does not need an absolute standard to make that determinaiton, just one consistently applied.
But they will not both actually BE slower, because it is NOT caused by "relative" motion, but rather by absolute motion.
They, why does the one that is really slower see the other as being slower at all? Until you answer that, your interpretation has a very large hole.
On the other hand, the accelerated observer is simply WRONG when he claims the other's clock have slowed down.
Why does he see a wrong thing?
Eric, can't you see that you contradict yourself in this very sentence?
I can see why you interpret it this way.
First you deny they occur, then you "explain" why they do in fact occur.
First: "I am saying there is no change to the yardstick/clock." Here you are saying there is no length contraction or time dilation.
Then: "Length contraction/time dilation is a result of path, not instrument." How could something which never happened to begin with "result" from anything?
Because the inertial state where the contraction/dilation occurs is different from the inertial state where they do not occur.
Don't confuse an "inertial state of motion" with an "inertial frame of reference."
I'll try to be more careful in my vocabulary.
Speaking of inertial "states of motion," that too is something to be posited. For Newton (and for Al in SR) the moon was NOT in a state of inertial motion (it was accelerated). In GR, it is in an inertial state of motion (unaccelerated). Which one is an empirical fact?
They use different definitions of acceleration, so each is an empirical fact under the defintion of acceleration used. In our discussion, we have agreed that the second case will not be called unaccelerated motion, but geodesic motion. So, by our usage, the moon is accelerated and moves geodesically.
In which type of "inertial frame" would the frame "cause" time dilation?
The motion itself is not a direct cause of time dilation.
No, it is not an illusion. The length of the perceived shadow has in fact changed, and the reason for the change can be explained completely apart from whether the "observer" is blind or not. It is not based upon subjective perception (or lack thereof).
Since the shadow changes, and the area of the shadow is the area of the light intercepted, I am assuming you will agree that the area of the light intercepted changes. If you don't, please ignore the next paragraph.
Now, without relaying on the shadow, if you have two people with yardsitcks, and the yardsticks are placed so that the extended lines would intersect in a 45-degree angle, then each person seens teh area of light intercepted by the other persons yardstick as being smaller than if the yardstick were parallel to his. This is not subjective, not an illusion, but a real physical trait which can cause other physical traits, like altered shadow. Note that each person sees the others yardstick as being shorter. Neither yeardstick is actually shorter, but the apparent shortness is a real, physical trait that has physcial effects (like altered shadows).
Similarly, an object moving in a different inertial state than I casts a different shadow than the same object moving in an identical inertial state. I see the changes as reduced length in the direction of movement and increased time, and those effects are as real. However, they are not due to a change in the object in a differentinertial state, but due to a difference in our inertial state. We are pointing away from each other, so to speak. Time dilation and length contraction are real, but not because anything changes the clocks and yardsticks.
One Brow said: "They, why does the one that is really slower see the other as being slower at all? Until you answer that, your interpretation has a very large hole."
I answered that in the sentence immediately preceding the one you quoted: "Both observers may "see" the other's clock as being slower (and these perceptions, considered in isolation, WOULD be the result of relative motion alone). But they will not both actually BE slower, because it is NOT caused by "relative" motion, but rather by absolute motion."
Regardless of who is moving, certain visual effects will be mutual and reciprocal. As you and I get closer to each, we will each "appear" bigger to the other, for example. That would be true whether I'm approaching you at 100 mph or your approaching me at 100 mph.
Where's the "hole?" The reciprocity of appearance certainly does not mean we're BOTH going 100 mph. It doesn't, in itself, tell you "who" is moving (or not moving), it happens either way. No big mystery there. That effect would happen regardless of who is moving.
Do you deny SR's conclusion about the matter:? "But they will not both actually BE slower, because it is NOT caused by "relative" motion, but rather by absolute motion."
Do you think both must actually BE slower?
Do you think such effects can only be caused by "relative motion," but would not occur with absolute motion?
One Brow said: "Neither yeardstick is actually shorter, but the apparent shortness is a real, physical trait..."
Eric, you are describing this as a pure matter of perspective, with no "real" physical effect. I can certainly understand that as a theoretical possibility. The problem here is that we are working within SR. SR may be COMPLETE BULLSHIT, I'll grant you that. But, for purposes of this discussion, we are assuming that it is correct and trying to determine the implications IF it is correct. Your suggestions are incompatible with the theoretical aspects of SR. They are also incompatible with the reports of certain finding and practical applications, like GPS. First, a few quotes:
"Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect..."
http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html
"According to special relativity, a properly functioning clock moving relative to you will tick slower than your clock, assuming that measurements are made in inertial reference frames. The moving clock will show a smaller number of seconds have passed if it is used to measure the duration of the same event that your clock is used to measure....Time dilation is not an illusion of perception; and it's not a matter of the second having different definitions in different reference frames."
http://library.thinkquest.org/C005644/Philosophy/ph6.htm
"...the two most important e ects predicted by the theory are derived: time dilation and length contraction....It is emphasized that the predicted e ects are real,not just apparent."
http://www.physics.nyu.edu/hogg/sr/sr.pdf
Why does this physicist emphasize that "the predicted e ects are real,not just apparent?" Well, for one thing, they are built into the mathematics of SR's formulas. These are designed to reflect "reality," not appearance. As I said before, in SR time dilation with increased speed is a FACT OF NATURE, which occurs regardless of whether any particular person knows it, accurately perceives it, etc. It is NOT, in any way, contingent upon perception. Questions of perception may be interesting, but they neither cause nor explain time dilation.
SR predicts that the travelling twin "really will" age less. Al HATED this consequence, but he was stuck with it. This is an asymmetrical, actual effect, according to the theory (the math). Length contraction and time dilation are built into the math, which, again, is advanced to explain physical reality, not subjective perception.
The speed of light could NOT be constant (or even be measured to be constant) without ACTUAL time dilation and/or length contraction. If such effects don't "really" happen, then the speed of light cannot "really" be constant, nor could it even be measured as "constant."
This is a matter of strict logical implication, whether you, personally, like to look at these changes as merely apparent, or not. If you have a different view, then you should merely repudiate SR rather than try to make your inconsistent hypothesis compatible with SR when it aint.
Again, one can just deny all validity to SR. But it would be much easier to blow off SR if the GPS clocks didn't ACTUALLY slow down. This is a real, lasting, and measurable fact, that does not "change with perspective."
One Brow said: "In our discussion, we have agreed that the second case will not be called unaccelerated motion, but geodesic motion. So, by our usage, the moon is accelerated and moves geodesically."
I didn't agree to this. GR IS different than SR, and I never tried to deny (or ignore) this difference. My complaint was about the equivocation involved in trying to equate "acceleration" in SR with "acceleration" in GR because they are completely different things. I objected to you trying to use GR's definition of "inertial motion" to explain "inertial motion in SR. I just asked that you not treat the two as identical. To keep things straight, we agreed to use "geodesic motion" when discussing GR concepts. At least that was my understanding.
To me it is very misleading to say, as you did, that "...the moon is accelerated and moves geodesically." This just reverts to the problem of failing to make a proper distinction between two different theories.
In his preface, the physicist I quoted earlier (David Hogg, from Princeton) elaborates on the difficulties people have distinguishing appearance from physical reality, as follows:
"A common confusion for students of special relativityis between that which is real and that which is apparent. For instance, length contraction is often mistakenly thought to be some optical illusion. But moving things do not "appear" shortened, they actually ARE shortened.
"How they appear depends on the particulars of the observation, including distance to the observer, viewing angles, times, etc. The observer finds that they are shortened only after correcting for these non-fundamental details of the observational procedure.
[Comment: Here he notes, as I was trying to say earlier, that matters of perspective are "non-fundamental details," and notes that AFTER correcting for such things, lengths REALLY ARE shortened]
I think these are very important aspects of special relativity, but from a pedagogical standpoint it is preferable to separate them from the basics, which are not dependent on the properties of the observer."
[Again, the basics ARE NOT "dependent on the properties of the observer."]
http://www.physics.nyu.edu/hogg/sr/sr.pdf
Eric, I tried to include a very explicit passage from the Princeton physicist about what is apparent and what is real with respect to time dilation, etc., but I don't see it. If it's not in the spam filter, let me know and I'll repost it.
The following "resolution" of problems is always readily available to one who doesn't really care to spend much time analyzing or "cross-checking" his beliefs, Eric.
Lets say I have good reason to believe A is true, and furthermore, that I have good reason to believe B is true. So, naturally enough, I believe A and B to both be true. If I go no farther than that, everything is fine.
But suppose I actually try to think about A & B in conjunction with each other, and not just accept their apparent truth solely on the basis of considering each in isolation from each other?
If I bother to do that (many people don't) some (real or apparent) inconsistencies may arise. This can be upsetting to some, because now their sense of "truth" may be undermined. In such circumstances, by far the easiest "resolution" would be along the following lines:
1. I have good reason to believe that A is true, and hence I do believe that A is true...
2. I have good reason to believe that B is true, and hence I do believe that B is true...
3. It is impossible for any true thing to be inconsistent with another true thing
4. For that matter, it is impossible for any true thing to be incompatible with known facts
5. Therefore both A and B are compatible with each other, and with all other known facts. Any "appearance," whether logical or empirical in origin, to the contrary MUST therefore be false.
End of story. All she done wrote. Very simple, actually. No need to think about it any more.
But they will not both actually BE slower, because it is NOT caused by "relative" motion, but rather by absolute motion."
One clock is really moving slower than the other one, according to you. Than has been clear. It does not answer my question.
Regardless of who is moving, certain visual effects will be mutual and reciprocal.
A mutual and reciprocal effect does not suffice. For example, clock A is really slowed, to the point where it ticks of 45 seconds for every 60 from clock B. That means that A sees the clock of B tick off 45 seconds for each of it's 60. If B has a mutual and reciprocal visual effect, he will see A tick off some 33.25 seconds to his 60. There has to be some effect to A which causes him to see Bs clock as being slower, but does not apply to B, for your position to work.
Do you deny SR's conclusion about the matter:? "But they will not both actually BE slower, because it is NOT caused by "relative" motion, but rather by absolute motion."
I don't deny SR's conclusion, because SR's conclusion does not rely on absolute motion. I just your interpretation of that conclusion, which does.
Do you think both must actually BE slower?
I think all the ways to determine an "actually slower" rely on selections that, from the standpoint of SR specifically (and not necessarily other physical notions), are arbitrary.
Do you think such effects can only be caused by "relative motion," but would not occur with absolute motion?
You say that as if there was some non-conceptual difference between relative motion and absolute motion.
Eric, you are describing this as a pure matter of perspective, with no "real" physical effect.
You have already acknowledged that the different shadows being cast was in fact a real, physical effect. Can a change of perspective enact a real, physical effect?
Your suggestions are incompatible with the theoretical aspects of SR.
You are incorrect.
They are also incompatible with the reports of certain finding and practical applications, like GPS.
You are extemely amusing.
First, a few quotes:
Your first and third agree with me that this is a real effect. The middle quote comes from a paper that seems to agree with your position (the wording seems a little fuzzy on this), but it was written by a student who shares your misunderstanding, not by a physicist.
Why does this physicist emphasize that "the predicted e ects are real,not just apparent?"
Because they are real.
This is a matter of strict logical implication, whether you, personally, like to look at these changes as merely apparent, or not.
I just posted two long paragraphs last night in which I explained they were real, not apparent.
I didn't agree to this.
Sorry, I had thought you agreed. What is your suggestion for terminology that properly desinguishes between the defintion of acceleration used in SR and the version in GR?
My complaint was about the equivocation involved in trying to equate "acceleration" in SR with "acceleration" in GR because they are completely different things.
They are similar concepts that wind up with different expressions. In both SR and GR, acceleration is the deviation from a path by an external force. GR just removes gravity from the list of external forces.
But they are different enough that I think different terms will help avoid confusion.
To keep things straight, we agreed to use "geodesic motion" when discussing GR concepts. At least that was my understanding.
That comports to my understanding.
To me it is very misleading to say, as you did, that "...the moon is accelerated and moves geodesically." This just reverts to the problem of failing to make a proper distinction between two different theories.
So, what would you consider the proper phrasing to say that under SR, the Moon accelerates, but under GR, it moves geodesically? Would you prefer to write to simply write out "under SR" and "under GR" for each usage?
Some quotes from Mr. Hogg, whose pdf you provided:
"As much as possible, the term 'to observe' will be used to mean 'to measure a real effect with a correct experimental technique,' while 'to see' will be reserved for apparent effects, or phenomena which relate to the fact that we look from a particular viewpoint with a particular
pair of eyes.'
So, with this very careful distinction:
"How it can be that both observers measure slower rates on the other's clock? The fact is, there is no contradiction, as long as we are willing to give up on a concept of absolute time, agreed-upon by all observers."
So, when using correct experimental technique, each measure the other's clock as being slower.
"Note that because there are no length changes perpendicular to the direction of motion, we cannot explain away time dilation and length contraction with length changes in the light-clock perpendicular to the direction of motion."
"That is, both observers find that the other's clock is going slow. There is no contradiction."
It's not because one person is wrong.
As long as you try to make point ouot that the effects of SR are not just a matter of perception, your points will be moot, because I already agree they are not matters of perception, but of observation.
One Brow said: "That is, both observers find that the other's clock is going slow. There is no contradiction."
One person IS WRONG. That fact, however, certainly does not contradict the fact each can "observe" each to be slower. It just can't be that they are each slower. You may be reading too much into the way he is trying to define "observation."
Elsewhere, he says, for example: "When Kepler first introduced a heliocentric model of the Solar System, it was resisted on the grounds of common sense. If the Earth is orbiting the Sun, why can't we "feel" the motion? Relativity provides the answer: there are no local, observational consequences to our motion."
Notice that even there are no "observational consequences" to our motion, he is clearly stating that the earth really is moving. Therefore, "observational consequences" do not dictate the underlying reality"
Eric, you just keep contradicting yourself insofar as you purport to accept SR, yet continue to make claims which contradict it. In the twin situation, which is true:
1. Each twin really is younger than the other
2. Each twin ages exactly the same, notwithstanding the travelling twin's trip
3. The travelling twin is "really younger."
4. The stay at home twin is "really younger."
5. Other answer (please specify)
One Brow said: "As long as you try to make point ouot that the effects of SR are not just a matter of perception, your points will be moot, because I already agree they are not matters of perception, but of observation."
You described it as a perception, but whatever. Now you need to make the distinction between an "observation" (as Hogg defines it) and physical reality.
For example, Hogg says:
"...D measures a shorter distance than E. D is moving relative to the planets A and B, while E is stationary. Planets A and B can be thought of as being at the ends of a ruler stick which E is holding, a ruler stick which is moving with respect to D. We conclude that moving ruler
sticks are shortened; this effect is length contraction, or sometimes Lorentz contraction."
He does not say all rulers are shortened, he explicitly says: "We conclude that MOVING ruler
sticks are shortened; this effect is length contraction, or sometimes Lorentz contraction." Prior to that he says: "D measures a shorter distance than E. D is moving relative to the planets A and B, while E is stationary."
The one who is moving will measure the shorter distance, and the stationary one (E) measures a longer distance. This is what SR tells you.
It is a pure non sequitur to claim, like our physicist friend, that "You can NEVER tell who is really moving!!" That changes nothing, for two reasons:
1. It is irrelevant. Whoever is moving faster (whether you can tell it or not) will measure the shorter distance and whoever is stationary will not.
2. In some cases you clearly can tell who is moving faster, and it is clearly a mistake to pretend otherwise.
Hogg makes this same point in a footnote (to the passage I already quoted about the lack of "observational consequences" of a moving earth:
"Actually, there are some observational consequences to the Earth's rotation (spin): for example, Foucault's pendulum, the existence
of hurricanes and other rotating windstorms, and the preferred direction of rotation of draining water. The point here is that there are no consequences to the Earth's linear motion through space."
One Brow said: "I don't deny SR's conclusion, because SR's conclusion does not rely on absolute motion. I just your interpretation of that conclusion, which does."
What do you think "absolute" means, I wonder? For it's predictions, SR relies on absolute acceleration, which results in "increased" speed. The "increase" is also absolute. In other words, when we blast Pioneer 1 off into space it REALLY IS going faster than we are.
That's what I mean, by absolute. I don't mean absolute in the sense that you can say the Pioneer is travelling "through space" at the rate of 20,000.06 miles per hour. I mean that it is "absolutely" going faster than us, and is moving away from, say, the Sun, at a speed that is absolutely (not relatively, not just "apparently") greater (hence faster) than we are.
Is that what you mean by absolute? Or do you have some other (irrelevant to my points) definition of "absolute" that you apply to my points, whether applicable or not?
I said: "Regardless of who is moving, certain visual effects will be mutual and reciprocal"
One Brow said: "A mutual and reciprocal effect does not suffice.... There has to be some effect to A which causes him to see Bs clock as being slower, but does not apply to B, for your position to work."
Does not suffice for what? For "my position to work" for what?
I simply said certain (meaning some, not all) VISUAL effects (as opposed to real effects) will be mutual and reciprocal, and there is no mystery in that, nor does it tell you that reciprocal "visual" effects must be real, objective, physical effects. You seems to think that what it MUST tell you ("There has to be some effect to A which causes him to see Bs clock as being slower, but does not apply to B, for your position to work."). Why MUST that be true? Because perception is reality, that the idea? Look....
1. Both can see the other as slower, but
2. Both cannot actually BE slower.
Is there a point you're driving at here? If my position "doesn't work," what does?
Are you claiming SR is wrong?
Are you saying each clock REALLY IS slower than the other?
Are you back to your claims that it is all unreal and illusory ("nothing changes with the clock, nothing changes with the rod").
What are you trying to prove, and how do you intend to prove (as opposed to just endlessly repeat) it?
One Brow said: "One clock is really moving slower than the other one, according to you."
How does that work according to YOU, exactly? That's what I'm trying to get you to spit out, and then justify. Simply telling me ad infinitum that you are right and that I am wrong doesn't cut it (for me, I mean--it obviously does for you).
I will tell you that I think you are contradicting yourself, I will tell just where I think the contradiction is, I will tell exactly why I think it is contradictory, etc., and I will invariably get only one response:
You will not address a word I said. You will invariably merely reply: "I am not contradicting myself?" Well, I shouldn't say invariably. Your alternative response it of course to tell me that I am a joke (again without trying to respond to and/or refute my points in any way and without offering the slightest bit of evidence or argument for your conclusions).
Very convenient, of course, and very common for those who can't or won't think or argue about anything. Assertion RULES!
One Brow said: "I just posted two long paragraphs last night in which I explained they were real, not apparent."
Really? Who knew? Was it whan you said this:?
"Because the inertial state where the contraction/dilation occurs is different from the inertial state where they do not occur."
Or was it when you called matters of perspective "real" and then said, that being mere matters of perception, time dilation and length contraction were real? What you say, Eric, is not simply the words you use. I look at your intended meaning, not your literal words (even though I know that you tend to think words define substance, rather than that substance indicates when one has made an inappropirate choice of words).
One Brow said: "Your first and third agree with me that this is a real effect."
Actually they disagree with you. You used the word "real" as something each of these quotes would REJECT as being "real." Everyone always seems to agree with you, Eric. If some stat guy says he likes pizza and that +/- stats are useless, and you say +/- stats are quite useful, you will insist that he agreess with you (because you like pizza too, but you don't disclose that).
Hogg says: "A common confusion for students of special relativityis between that which is real and that which is apparent. For instance, length contraction is often mistakenly thought to be some optical illusion. But moving things do not "appear" shortened, they actually ARE shortened."
You say: "Because the inertial state where the contraction/dilation occurs is different from the inertial state where they do not occur."
Your reference is SOLELY to different perspectives. Hogg makes it clear that different perspectives have NOTHING to do with it.
I said: " He does not say all rulers are shortened, he explicitly says: "We conclude that MOVING ruler sticks are shortened; this effect is length contraction, or sometimes Lorentz contraction."
It is called a Lorentz contraction for a reason. Al lifted the notion from Lorentz, wholesale. Lorentz contrived it precisely to explain why MOVING RULERS and ONLY moving rulers contracted. It does work any differently for Al than it did for Lorentz, and it doesn't work any differently today than it did over 100 years ago when Lorentz (perhaps more properly Fitzgerald, but...) conceived it. It is a formula which shows how length contracts WITH MOTION, and remains uncontracted in the absence of motion. I went over all of this not long ago in this thread.
Given it's nature, the formula works just as well to predict that INCREASED MOTION will necessarily result in INCREASED length contraction, assuming the unaccelered ruler was already in motion itself.
In similar fashion, Hoggs also says that "moving clocks" (not ALL clocks) slow down, and this is precisely the explanation he uses to explain the twin phenomenon:
"From M's point of view, the journey will
take time T = 2`=u 60 yr, so L will return when M is 80. How much will L have aged over the same period? In Section 2.1 we learned that MOVING CLOCKS [emphasis mine] go slow so L will have aged by T0 = T=, where
(1− 2)−1=2and u=c. For u = 0:99c,
= 7, so L will haveaged less than 9 yr. That is, on L's arrival home, M will be 80, but L will only be 28!"
Hoggs agrees with what I have been saying. If you don't agree with me, fine, then say why. But don't say he agrees with you. And don't say SR agrees with you, either, eh?
Parody skit of the day:
Eric: The claim that Obama spent 17 years in prison in an outright lie!
Aint: Well, Eric, the NYT reported today that Obama spent 17 years and prison and claims it is true.
Eric; See! The NYT agrees with me!
Aint: How ya figure? You said it was an outright lie, they said it was true.
Eric: Because an outright lie is true. If someone lies, it is true that they told a lie.
Aint: Yeah, so?
Eric: So the NYT agrees with me that it is true, see?
Aint: Yeah, I see, sho nuff.
A couple of things worth emphasizing about "observation" (I have pointed these out many times, but I doubt that they have sunk in yet). As Hogg defines it: "...it is important to distinguish between what an ideally knowledgeable observer observes and what an ordinary person sees...the term "to observe" will be used to mean "to measure a real e ect with a correct experimental technique."
So, basically, what we have is an "ideally knowledgeable observer" (would that be, like, God, I wonder?) who is correctly "measuring" something "real."
1. A "correct measurement" does not imply a correct conclusion about the import of the measurement. Many assumptions, some perhaps mistaken, intervene in the process of drawing a conclusion on the basis of a "correct measurement." I think you may be equating an "observation" with something like "discovery of an indisputable fact." Perhaps you're not, but if so, that is not what an "observation" is.
2. Hogg doesn't always seem to follow his own advice. An "ideally informed" observer would know if he has been accelerated (or more accelerated) with respect to other objects and, likewise, whether they had been (more) accelerated than him. Hogg doesn't explicitly say it, but Hogg means that an "ideally knowledgeable" observer would use his knowledge to correct/refine the import of his measurements (he makes this clear in his examples of how one converts what he "sees" into an "observation").
Given that definition, no observer would EVER think that the clocks on an object less accelerated than him were running slower than his. On the contrary, he would realize, under those circumstances, that his clocks were the ones running slower. Likewise, such an observer would always know that the clocks on an object more accelerated than him were running slower than his.
This whole thing about how "each observes the other's clock as running slower" is strictly conditional. That can only be true when BOTH assume that they are less accelerated. In such a case ONE of them is NOT "ideally knowledgeable."
I asked: Do you think both must actually BE slower?
One Brow said: I think all the ways to determine an "actually slower" rely on selections that, from the standpoint of SR specifically (and not necessarily other physical notions), are arbitrary.
The typical, evasive, non-answer given by one brainwashed by the already brain-washed. Until you understand certain things, Eric, we'll never rescue you.
1. Do you understand that SR is a mathematical theory? Do you understand that the math dictates certain cold, hard, inescapable conclusions which have nothing to do with my (or your) "interpretation" or "philosophy?'
2. Do you understand that SR is a theory about the nature of the physical world, and not the observers in it? Do you understand that's it's necessary implications would hold EVEN IF every observer in the world died off, i.e., do you understand that the consequences of the theory are completely independent of each and every possible observer?
3. Do you understand that the predictions that SR makes are completely independent of what YOU, or anybody else, knows about any particular moving object(s)?
4. Will you just answer the question asked, rather than evade it?
One person IS WRONG.
According to Mr. Hogg, whose tract you offered as authoritative, that is incorrect. The Way he uses terminology, what you see can be wrong. What you observe will be correct, because when you observe, as opposed to see, you are using correct experimental technique to adjust for what you see.
I do laugh a little when you offer something as an authority and then proceed to say they are wrong on the very point you are trying to cite them for.
Notice that even there are no "observational consequences" to our motion, he is clearly stating that the earth really is moving. Therefore, "observational consequences" do not dictate the underlying reality"
Standard relativity theory is that correctly performed, identical experiements will have identical results in different inertial states. So, that fits precisely with the usage of "observe" I noted earlier.
Eric, you just keep contradicting yourself insofar as you purport to accept SR, yet continue to make claims which contradict it. In the twin situation, which is true:
I have said many times the travelling twin is really younger. At the end of the journey they are standing right next to each other, and it is obvious one if younger.
You described it as a perception, but whatever.
You objected to the definition of perception I used for that, so I changed it to "angle of incidence".
He does not say all rulers are shortened, he explicitly says: "We conclude that MOVING ruler
sticks are shortened; this effect is length contraction, or sometimes Lorentz contraction." Prior to that he says: "D measures a shorter distance than E. D is moving relative to the planets A and B, while E is stationary."
"Indeed this is true; after all, all of the above arguments are equally applicable if we swap D and E. This is the fundamentally counterintuitive aspect of relativity. How it can be that both observers measure slower rates on the other's clock? The fact is, there is no contradiction, as long as we are willing to give up on a concept of absolute time, agreed-upon by all observers."
Do you really think Hogg holds this is true of the clocks, but not the rulers? Seriously?
It is a pure non sequitur to claim, like our physicist friend, that "You can NEVER tell who is really moving!!" That changes nothing, for two reasons:
1. It is irrelevant. Whoever is moving faster (whether you can tell it or not) will measure the shorter distance and whoever is stationary will not.
So, the person that is moving will observe the person that is stationary to have a longer ruler?
2. In some cases you clearly can tell who is moving faster, and it is clearly a mistake to pretend otherwise.
You can set up the traveling twin scenario so that on one leg of the journey, the travelling twin is moving slower than the "stationary twin". the answer does not change.
What do you think "absolute" means, I wonder?
That there is some inertial state that represent "really" not moving, and all other inertial states are really moving.
For it's predictions, SR relies on absolute acceleration, which results in "increased" speed.
SR only needs changed speed, not increased speed. The effects are the same if the speed is decreased.
The "increase" is also absolute. In other words, when we blast Pioneer 1 off into space it REALLY IS going faster than we are.
Aren't we moving around the sun? If we blast it off in the opposite direction, wouldn't you consider that to be slower than us?
I mean that it is "absolutely" going faster than us, and is moving away from, say, the Sun, at a speed that is absolutely (not relatively, not just "apparently") greater (hence faster) than we are.
If you can't put a number on the speed of Pioneer or on our speed, how do you know Pioneer is faster?
Why MUST that be true? Because perception is reality, that the idea? Look....
1. Both can see the other as slower, but
2. Both cannot actually BE slower.
Is there a point you're driving at here?
The point is you need to account for why the person who is slower observes the other person to be slower as well, instead of faster. Simply saying he is wrong (sorry, WRONG) does not explain why he makes a wrong observation.
Are you claiming SR is wrong?
No.
Are you saying each clock REALLY IS slower than the other?
Different inertial states will measure different cloaks as being slower, because the relative speed of the clock is dependent on the inertial state you are in. If you firmly commit to a particular inertial state, then in that inertial state you can say whether or not one clock is slower, but this does not carry over into every inertial state.
Are you back to your claims that it is all unreal and illusory
I did not make such a claim.
("nothing changes with the clock, nothing changes with the rod").
This is not a claim that the effects are unreal nor that they are illusory.
What are you trying to prove, and how do you intend to prove (as opposed to just endlessly repeat) it?
Proof is for mathematicians and alcohol. I am not even trying to provide evidence, we have seen plenty of references to it. I am trying to provide a description, nothing more.
Really? Who knew? Was it whan you said this:?
April 6, 2011 9:21 PM
"Now, without relaying on the shadow, if you have two people with yardsitcks, and the yardsticks are placed so that the extended lines would intersect in a 45-degree angle, then each person seens teh area of light intercepted by the other persons yardstick as being smaller than if the yardstick were parallel to his. This is not subjective, not an illusion, but a real physical trait which can cause other physical traits, like altered shadow. Note that each person sees the others yardstick as being shorter. Neither yeardstick is actually shorter, but the apparent shortness is a real, physical trait that has physcial effects (like altered shadows).
Similarly, an object moving in a different inertial state than I casts a different shadow than the same object moving in an identical inertial state. I see the changes as reduced length in the direction of movement and increased time, and those effects are as real. However, they are not due to a change in the object in a differentinertial state, but due to a difference in our inertial state. We are pointing away from each other, so to speak. Time dilation and length contraction are real, but not because anything changes the clocks and yardsticks. "
Actually they disagree with you. You used the word "real" as something each of these quotes would REJECT as being "real."
While it's nice of you to speak for them, you misunderstand them.
Everyone always seems to agree with you, Eric.
Hardly. I acknowledged the second paper did not seem to agree with me. However, I do try to accept the explanations of experts, so I agree with them not because I am so bright, because I alter my opinions when it is appropriate to do so. Once I alter my opinions to agree with them, by the reflexive property of agreement, they agree with me.
Hogg says: "A common confusion for students of special relativityis between that which is real and that which is apparent. For instance, length contraction is often mistakenly thought to be some optical illusion. But moving things do not "appear" shortened, they actually ARE shortened."
You say: "Because the inertial state where the contraction/dilation occurs is different from the inertial state where they do not occur."
Your reference is SOLELY to different perspectives. Hogg makes it clear that different perspectives have NOTHING to do with it.
Your error is to think that being in different inertial states is solely a matter of perspective, as opposed to a physical reality with physical consequences. Much like the same yardstick will cast different shadows at different angles, being in different inertial states means observing (as opposed to seeing) different aspects.
Given it's nature, the formula works just as well to predict that INCREASED MOTION will necessarily result in INCREASED length contraction, assuming the unaccelered ruler was already in motion itself.
Yet, you offer no evidence for length dilation when something is moving slower, nor a reason why the moving observer will observe contraction instead of dilation.
Hoggs agrees with what I have been saying. If you don't agree with me, fine, then say why. But don't say he agrees with you. And don't say SR agrees with you, either, eh?
"Indeed this is true; after all, all of the above arguments are equally applicable if we swap D and E. This is the fundamentally counterintuitive aspect of relativity. How it can be that both observers measure slower rates on the other's clock? The fact is, there is no contradiction, as long as we are willing to give up on a concept of absolute time, agreed-upon by all observers."
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