This is the second in a series of posts that will be reviewing and responding to the arguments of Dr. Feser's The Last Superstition. This was part 1. I haven't read many books of philosophy, and none aimed at popular audiences, so when I note that Dr. Feser starts out with a list of claims that he promises to demonstrate later, I have no idea if that is standard procedure or not. It does make the first chapter, Bad Religion, devoid of meaningful content with regard to establishing Dr. Feser's claims. However, one of the things I want to do is to in this post is list all these promises Dr. Feser makes in Chapter 1. After I review the last chapter, I will return to this list and we will see what has actually been proven.
Claims Dr. Feser says he will demonstrate
Secularism is inherently immoral and irrational, only a specific sort of religious view can be moral, rational, and sane
On intellectual grounds, atheism can not be true
Secularism can never spring from reason; its true grounding is from a willfulness and desire for it to be true
The basic metaphysical assumptions that make atheism possible are mistaken
Secular propaganda is the source of fideism
It is as impossible to say nature has no meaning or purpose as it is to square a circle (more on that below)
Secularism is parasitic on religion for all its important ideas, it is strictly a negation
What is characterized as a war between science and religion is really a war between competing metaphysical systems
The classical metaphysical picture is rationally unavoidable, and thus so is the traditional Western religious view derived from it
Given atheism and naturalism, there is no persuasive argument that allows you to trust in either reason or morality
Edit on 2009-NOV-17 to add: The abandonment of Aristotle's metaphysics has led to the abandonment of any rational or moral standards that can be used to justify moral positions, and is responsible for the curent civilizational crisis of the West.
Dr. Feser allows himself a full 241 pages in the next five chapters to accomplish all this. Of course, with so modest an undertaking, he leaves himself plenty of space to continue to denigrate atheism, secularism, the New Atheists (Dawkins, Dennett, Harris, and Hitchens), Hume, and many more in those chapters as well.
I do have a few other comments on some of Dr. Feser's remarks in chapter 1. While I still intend to avoid responding to the mere demagoguery that he indulges himself in, there are a few points that reveal interesting and noteworthy aspects of both him and his opinion of his audience.
There is nothing particularly noteworthy or striking about his claim that the less people know, they less they realize their ignorance. In fact, I read similar thoughts from a variety of science books and scientists growing up, typically along the lines of 'The more you know, the more you realize how little you know'.
I do not agree that attempts to account for phenomena such as the mind without referencing God is a religious discussion. You might as well say that attempts to account for lightning without referencing God is a religious discussion. Then again, perhaps Dr. Feser would say that. I would not be surprised at all to see him claim that any discussion of any natural phenomenon is inherently religious.
One of the common hallmarks of purveyors of woo is a sense of persecution that results from being treated equally. This comes out twice in Chapter 1, where first Dr. Feser complains that some philosophical positions distasteful to him are considered still worth discussion even when they can't be demonstrated, while the subject of religion is considered not to have made its case. Of course, the second standard is a far higher hurdle than the first, and certainly not to be awarded lightly. To imply that religion must be granted the second when other positions are granted the first, or else the supporters of the second are receiving unfair treatment, sounds very much like a persecution complex. Shortly after that, he complains that the distasteful propositions are referred to as making people think, whereas in this context religion is apparently not worthy of a moment's notice. He acknowledges that most people are raised religiously, but somehow misses the point that immersing people in thoughts they already find comfortable will be doing the opposite of making them think, it is much more likely to lull them to stupor. However, the concern seems to be for some sort of time equality, not purpose, because otherwise religious ideas are just not being treated fairly.
Dr. Feser pulls out the old saw about the desire to disbelieve in hellfire being a motivation for atheism. Oddly, I have met very few Christians who believed they, personally, were going to hell. I certainly never did, back in the day. He doesn't seem to understand the human tendency for exceptionalism, or to be deliberately ignoring it.
Dr. Feser declares that the notions of a selfish gene, or design via natural selection, can only be true and interesting if by these terms we attribute some superhuman, literal intelligence to the gene and the process. I'm not sure what to make of this. Obviously he knows the terms are metaphors that describe the complex interactions of various feedbacks mechanisms. He doesn't think that the study of feedback mechanisms is interesting, that the feedback mechanisms are not true, or that the use of metaphor makes the concept untrue or uninteresting?
Dr. Feser complains about 'Easter Bunny comparisons to God', which he disdains. This is all fine for him, but the authors upon whom he heaps this disdain are do not have the audience of his peers in mind; their books are for the general public, and often specifically the religious members thereof. The Easter Bunny example actually strikes right at the heart of what many of these people believe. If the religious group doesn't have their followers trained in the ideas of Aristotle, why should it be the job of Dennett, et. al., to train them? Later on, Dr. Feser says that this is an example of these authors not being willing to take on the real issues against the formidable opposition. With all the diminutions hurled against these authors, you would think he believe this is the appropriate level of opposition for them, but I suppose he thinks even more poorly of his fellow believers in this regard. At any rate, while I might not have the training of a Dennett, I am happy to accommodate Dr. Feser by engaging his ideas directly. Having read through Chapter 4 so far, I have not found any reason to see his presentation of reason, faith, and religion as having a superior metaphysical basis to your typical Sunday preacher.
Finally, Dr. Feser likes to make great use out of the metaphysical absurdity of square circles. He is unaware that all circles are indeed squares, under the taxicab metric (I'll devote a separate post to that). This is a problem with his metaphysical analysis that we’ll cover in more detail later. For now, let’s just say that like any other formal system, Aristotle’s metaphysics will turn out to be founded on arbitrarily chosen premises that are inherently improvable and not obviously better than a variety of alternatives as a description of reality.
Monday, October 19, 2009
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«Oldest ‹Older 401 – 600 of 1677 Newer› Newest»1. I don't intend to "present a model," if that's what you're expecting. Research the matter yourself if you want one.
I've done a lot of reading on this material in this discussion. I haven't seen one. One may exist or be created at any moment, of course.
2. You refer to ether, but it's not still 1905, ya know? As I understand it, in the neo-lorentizian view what is sometimes called "ether" really just reduces to gravitional effects. I realize that "gravity" is a very suspect concept, all on it's own, but LR doesn't appeal to it any more than GR does.
At least in the case of Van Flandern, the reason for the altered path of light in the gravity well of the sun was refraction through an increased concentration of ether. Maybe he meant ether metaphorically, of course.
One clock stays stationary, one is accelerated and then returns. I trust that you agree that they will read differently, irrespective of the way the clock is designed.
Why should mere speed "cause" that? Did this happen by "magic?" Yeah, I spoze. I guess it just a question of whether you want to attribute "magical" powers to time or gravity.
Why not both? :)
Not sure I understand this, but I don't think I agree. As I see it, all time-keepers are based upon the presumed frequency of a consistently recurring event. Not sure how "delay" would be involved here, unless maybe you are referring to "duration."
Yes, duration between specific events that have been calibrated.
I would have to guess that any changing of the measurement of time therefore means a changing of that frequency (from what it was initially presumed to be to something else). The time-keeper would still be based on regularly recurring events, but the rate of the occurrence of those events has changed. Temperature can directly affect some types (ultimately even all types, I spoze) of clocks, but not because time itself has slowed down or speeded up.
Absolutely temperature will affect them all. However, temperature will affect them all *at different rates*. Purely electrical clocks will be relatively untouched campared to mechanical clocks.
But of course speed is merely distance/time. How do we determine these? I mean, we know the answer to the division problem (186,000 mps), in advance, and don't even have to think about that (given SR postulates), but how do we know how "far" something is from us or how much "time" it took the light to get to us? Does the doppler effect change the way we calculate the distance? The way we calculate the time? Both?
It changes the perceived wavelength of the light as well as how far apart we see different bursts of light.
I mean, like, do I know a star is 5 light years away from us (a measurement of distance) because I know it took light from it 5 years to get here? How do I know when the light I am seeing now left, exactly?
I believe many of those measurements are performed by parallax, as opposed to relativistically. At least, parallax can confirm any results withinn a few hundred light-years or so.
Does it matter if the star is approaching me, receding, or staying equidistant? If it matters, how do I know if it was doing that 5 years ago?
YOu can compare the parallax measurement every year to the prior year to see relative movement.
Or, in the case of distant stars, say 100 million years ago.
That far away, I don't know.I suppose if you make some assumptions about whether the star is burning a specific fuel, say hydrogen, since we know that fusing hydrogen emits a specific set of light frequencies, we can look for those frequencies. If they are blue-shifted (that is, a little bluer than we would expect), the star is moving toward us. If they are red-shifted, it is moving away. The error bars are probably fairly large.
Which is just another way of saying that only Einstien's formulation is Einstien's formulation, aint it? Kinda goes without sayin, I spoze.
Einstein's formulation, and understanding, is pretty much the modern concensus.
From what I understand, Einstien's derivation of e = mc2 (when he finally reached it after previous formulations) was mathematically erronous, but I guess that's neither here nor there, except to wonder how he can erroneously "derive" such a magnificent formula.
I did that once on a calculus test. I made two errors in arithmetic and came up with the right answer.
SR would explain this as being due in part to it's altitude (less gravity) and in part to it's increased rate of speed, as I understand it.
How does "time" cause the speed element? How does "gravity" cause the altitude element? How does a "dimension" effectuate an observable difference in the number of ticks made by each clock? How does "gravity" do it, for that matter?
Technically, the height part fo the explanation is GR, not SR.
My best response that the dimensions don't effectuate any change, and the clocks operate normally within that dimensional manifold.
It's the "time" thing I'm really curious to hear your response to, though. How does time, qua time, "cause" the clock to slow down?
By slowing down itself.
Now, if you were stationary on the surface of the star, the light hitting your eyes would have left earth 4 years ago. But if you are receding from the earth (and the "stationary" star), the light which left earth 4 years ago, and is "just now" hitting the surface of the star, cannot be seen by you because you have outran them. The only light from earth which you can "now" see had to leave earth MORE than 4 years ago. This situation reverses itself when you are approaching earth at a high rate of speed. So, as I said, I guess he is talking about the doppler effect, or some variation of it.
Is the claim that you see time running forwards and backwards, or just the that orbiting planet since widely varying shifts in the rate of time it observes on earth, but does not see a reversal? I would agree with the later. Or, is this a reference to the "time Slippage" calcuation made from the reference frame of the planet being stationary, the results of which calculation can not be seen from the planet?
One Brow said: "It does *not* say he had the model in hand to present. In fact, it says Bell only had the small bits that could be the beginning of the model."
Yes, it does say he had a model in hand. The original question was whether he had a model, which you denied. You seem to now want to change this to a discussion of his model's merits. We can do that, but let's not pretend that was the issue before, OK?
The author is question says: "Bell’s model has as its starting point a single atom built of an electron circling a much more massive nucleus....He went on to demonstrate that there is a system of
primed variables such that the the description of the uniformly moving atom with respect to them is the same as the description of the stationary atom
relative to the orginal variables—and that the associated transformations of coordinates are precisely the familiar Lorentz transformations. But it is important to note that Bell’s prediction of length contraction and time dilation is based
on an analysis of the field surrounding a (gently) accelerating nucleus and its effect on the electron orbit.12"
This same author concluded that Bell's model was not "truly satisfactory," but at the same time says Bell should not be "berated" for that: "Bell cannot be berated for failing to use a truly satisfactory model of theatom; he was perfectly aware that his atom is unstable and that ultimately only a quantum theory of both nuclear and atomic cohesion would do."
Not having a model that is "truly satisfactory" is not the same as not having a model, period.
Indeed, in the opinion of this author that particular deficiency lies with GR, not Bell's model: "[Bell wished to demonstrae that] a moving rod contracts, and a moving clock dilates, because of how it is made up and not because of the nature of its spatiotemporal environment. Bell was surely right. Indeed, if it is the structure of the background spacetime that accounts for the phenomenon, by what mechanism is the rod or clock informed as to what this structure is? How does this material object get to know which type of spacetime—Galilean or Minkowskian, say—it is immersed in?"
http://philsci-archive.pitt.edu/archive/00000987/00/Michelson.pdf
So, in his opinion, Bell is right, and his model was sufficient to achieve his (pedagogical) purposes. On the other hand, GR proposes no mechanism or model at all to explain why a moving clock will lose it's prior agreement with a non-moving one. It is GR that has no model, not LR, as I read this guy.
One Brow said: "Actually, the solution is that the question of who is younger at any given moment when the twins are not together will be observer-dependent."
I agree that this is the proper answer (rather than 10 pages discussing doppler effects, etc.), but I'm not sure it is the "solution" to the question posed. It is, in fact, that very answer which raises the question asked.
The proper answer, made more explicitly, would probably be more like: Whether one is "really" younger than the other, or, for that matter, whether they are "really" the same age in unknown and unknowable. There is a correct answer, but in order to know it we would need to know which one(s) is "really" moving, and at what rate(s). We cannot know that, so don't ask.
That answer is acceptable, but not when coupled with the claim that all views are "equally valid" (as opposed to equally unknowable).
In other words, as I have said before, it is the attempt to demonstrate than one twin "really" is older and one who "really" is younger, that is misguided and which betrays the very premises it supposedly adopts at the outset.
One Brow said: "So, since one twin undergoes 3-4 rounds of acceleration detectable from his own reference frame, ane the other twin does not, the equations treat the reference frames unequally."
Ya see, this is just another way of saying that it can, in fact, be determined that one twin "really" is older, and that claim contradicts your final statement to the effect that: "Atually, the solution is that the question of who is younger at any given moment when the twins are not together will be observer-dependent."
In this case it is not "observer-dependent" because there is a "true" answer (and therefore a false, or incorrect, answer) which exists independently of the observations of either twin. Keep in mind that even though one twin will "observe" the effects of acceleration/gravity, those are not phenomena which his observations control; he is merely sensing something "real" which exists whether he observes it or not.
One Brow said: "I believe many of those measurements are performed by parallax, as opposed to relativistically. At least, parallax can confirm any results withinn a few hundred light-years or so."
1. Wouldn't a parallax calculation entail a reliance on euclidean geometry, which, you say, doesn't apply to "real" space?
2. What good would it do to "confirm" something to "within a few hundred light-years or so?" This would not allow any reliable conclusions about distances used in calculating the speed of light, would it?
One Brow said: "I've done a lot of reading on this material in this discussion. I haven't seen one."
I said: "As I understand it, in the neo-lorentizian view what is sometimes called "ether" really just reduces to gravitional effects."
You responded: "At least in the case of Van Flandern, the reason for the altered path of light in the gravity well of the sun was refraction through an increased concentration of ether. Maybe he meant ether metaphorically, of course."
======
Below are two quotes from an article by Van Flandern, cited very early in this discussion, which addressed both of your comments, above:
"LR went in the opposite direction, specifying that the generalized, amorphous, universal aether of LET should in fact be identified with the local gravitational potential field, which is of course a different frame from place to place."
"The modern development of LR from the original LET theory published by Lorentz, specifically the identification of the preferred frame with the local gravity field, can be attributed to Tangherlini [[ix]], Mansouri & Sexl [[x]], Beckmann [[xi]], Hayden [[xii]], Hatch [[xiii]], and Selleri [[xiv]]."
http://www.metaresearch.org/cosmology/gravity/LR.asp
The original question was whether he had a model, which you denied. You seem to now want to change this to a discussion of his model's merits. We can do that, but let's not pretend that was the issue before, OK?
Having small bits that you might put into a model is not the same as having a model. Again, if you think he had a model to present as an alternative, and yet still could not achieve presenting it, you are casting upon Bell a high degree of incompetence as an instructor.
This same author concluded that Bell's model was not "truly satisfactory," but at the same time says Bell should not be "berated" for that: "Bell cannot be berated for failing to use a truly satisfactory model of theatom; he was perfectly aware that his atom is unstable and that ultimately only a quantum theory of both nuclear and atomic cohesion would do."
Not having a model that is "truly satisfactory" is not the same as not having a model, period.
If your purpose is to teach an alternative model to standard SR/GR, the difference is minimal. Subatomic elephants that compress atoms is also a model, but not a satisfactory one.
Indeed, in the opinion of this author that particular deficiency lies with GR, not Bell's model
A dislike for GR is not enough to say you have an alternative model.
How does this material object get to know which type of spacetime—Galilean or Minkowskian, say—it is immersed in?"
Under SR/GR, it would not know and there is no need for it to know.
It is GR that has no model, not LR, as I read this guy.
The change in rate at which time passes seems to be a passable model, regardless of his opinion.
One Brow said: "Actually, the solution is that the question of who is younger at any given moment when the twins are not together will be observer-dependent."
I agree that this is the proper answer (rather than 10 pages discussing doppler effects, etc.), but I'm not sure it is the "solution" to the question posed.
Since the question posed concerned differing inertial environments only (this was not a response to the twin paradox), it is all the solution that is available.
The proper answer ... We cannot know that, so don't ask.
This answer is based on the assumption that there can be an objective frame of reference.
In other words, as I have said before, it is the attempt to demonstrate than one twin "really" is older and one who "really" is younger, that is misguided and which betrays the very premises it supposedly adopts at the outset.
In the twin paradox, at the end of the situation both twins are back in the same inertial reference frame and not too distant spatially. This means we can discuss who has experienced a greater passage of time relatively coherently.
Ya see, this is just another way of saying that it can, in fact, be determined that one twin "really" is older, and that claim contradicts your final statement to the effect that: "Atually, the solution is that the question of who is younger at any given moment when the twins are not together will be observer-dependent."
I did not use the sentence you have in quotes, and that solution was not to the twin paradox, but to the situation of two people born near each other spatially but in different, unchanged inertial reference frames.
In this case it is not "observer-dependent" because there is a "true" answer (and therefore a false, or incorrect, answer) ...
In the case of the twin paradox, yes, and both twins arrive at the same answer.
One Brow said: "I believe many of those measurements are performed by parallax, as opposed to relativistically. At least, parallax can confirm any results withinn a few hundred light-years or so."
1. Wouldn't a parallax calculation entail a reliance on euclidean geometry, which, you say, doesn't apply to "real" space?
You can change using straight lines to using null geodesics in the presence of a sufficiently large gravitational mass.
2. What good would it do to "confirm" something to "within a few hundred light-years or so?" This would not allow any reliable conclusions about distances used in calculating the speed of light, would it?
If you can use parallax to confirm the effects of Doppler shifting of the hydrogen spectrum on several stars that are 100-200 light-years distant, that provides confidence in using it on stars too far to be meausred by parallax.
Below are two quotes from an article by Van Flandern, cited very early in this discussion, which addressed both of your comments, above:
Do those quotes mean gravity instead of ether, or gravity collects ether? They seem to fit either way.
One Brow said: "Do those quotes mean gravity instead of ether, or gravity collects ether? They seem to fit either way."
I haven't read any of it but I think the idea in at least some of these theories is that the gravity "collects" or "entrains" the ether, and that the slowing of clocks is explained by the gravitational effects, ultimately.
It is my understanding that SR would be totally unaffected whether or not an ether is postulated, i.e., that it's validity would in no way be undercut by the existence of an ether. I also think many LR advocates do not even seek to demonstrate absolute motion, but believe that even an arbitrarily-designated "rest frame" would provide theoretical advantages.
One Brow said: "A dislike for GR is not enough to say you have an alternative model." Are you saying that this is all Bell did?
If your objection to theory "a" is that it provides no model, then model "b"should be rejected on the same grounds. If theory "a" has a model, and theory "b" doesn't then theory "a" would be preferred if that is your main criterion, eh? Which is it? Do you demand an adequate model to gain your allegiance, or is that just a post hoc objection to OTHER theories (but excluding your favorite) AFTER you have made your choice on wholly independent grounds?
If you wish to stick to your black or white, arbitrary designations that a theory is either:
1. TRULY SATISFACTORY, or else
2. It consist of only "small bits,"
then I won't argue with you all day, because you can always ignore substance in favor of subjective characterization.
One Brow said: "If you can use parallax to confirm the effects of Doppler shifting of the hydrogen spectrum on several stars that are 100-200 light-years distant, that provides confidence in using it on stars too far to be meausred by parallax."
I really don't see what a doppler effect would tell you about how far away an object is, but I will note this:
Given the SR postulate about the necessary answer to the speed of light, then only one variable (time or distance) needs to be determined to "know" the other. As soon as I say that object x is a certain distance away, I "know" how long ago the light I am seeing now left it. I also "know," by postulate, that it's speed was constant during the course of it's million-year journey, and did not vary due to interaction with "dark matter," black holes, or any other factor.
It's really not that hard to "know" things which you assume a priori.
The problem, of course, is that I must rely on the light I am seeing to help determine the distance, so it all becomes rather circular. Furthermore, it would seem to make a difference how "distance" is to be "measured" (deduced is the real word here). In "straight lines," or would a curved line be longer than a straight one?
I haven't read any of it but I think the idea in at least some of these theories is that the gravity "collects" or "entrains" the ether, and that the slowing of clocks is explained by the gravitational effects, ultimately.
I didn't read Van Flandern, in particular, that way, but I may have misunderstood.
Are you saying that this is all Bell did?
I beleive my response, and quote, was of the author of the paper, not of Bell.
If your objection to theory "a" is that it provides no model, then model "b"should be rejected on the same grounds. If theory "a" has a model, and theory "b" doesn't then theory "a" would be preferred if that is your main criterion, eh? Which is it?
I need to choose and draw clear bright lines? I need to a have one supreme criterion? I need to make absolute declarations on worthiness? No, I don't think so.
I really don't see what a doppler effect would tell you about how far away an object is,
You're right, but it can tell you the rate at which an object is approaching or receding.
I also "know," by postulate, that it's speed was constant during the course of it's million-year journey,
Unless it was slowed by passing through a medium of some sort, of course.
Again, the constancy of the speed of light is only true until it isn't. When some observation or experiment proves truly incompatible with this notion, it will be dropped. For now, since light moves at the same rate against a current and with that current (for example), we treat it as being unchanged.
The problem, of course, is that I must rely on the light I am seeing to help determine the distance, so it all becomes rather circular. Furthermore, it would seem to make a difference how "distance" is to be "measured" (deduced is the real word here). In "straight lines," or would a curved line be longer than a straight one?
The null geodeisic would be the shortest path between two points, regardless of how curved it is.
In response to: "How does this material object get to know which type of spacetime—Galilean or Minkowskian, say—it is immersed in?"
You said: "Under SR/GR, it would not know and there is no need for it to know.
Apparently you don't understand the question, which I take to be along the lines I have already raised, i.e.:
"What you seem to be suggesting is that there is in fact an absolute, independently existing thing called "time," which clocks sense and respond to. It's like a clock somehow knows what a "real" second is (because time tells it) and changes its rate of mechanical operation to comply with the dictates of time (rather than to the springs, gears, etc. contained within it). If time slows, then the clock makes internal changes to slow it's own ticking rate because time has "told" it to."
One Brow said: "The null geodeisic would be the shortest path between two points, regardless of how curved it is."
The question wasn't about the "shortest path," though, it was about distance. The "shortest path" tells you nothing about the distance. If I tell you that the "shortest path" to London from New York is over the ocean waves (which go up and down) what does that tell you about how far they are from each other? Nothing, right?
One Brow said: "since light moves at the same rate against a current and with that current (for example), we treat it as being unchanged."
Of course LR would say that it doesn't "move at the same rate." In SR the "same rate" is merely postulated, not measured. And it will not "change" unless and until the postulate is changed. Again, you are just claiming that you "know" what you assume.
Suppose I tell you that there are 3 balls in an urn, one white, one blue, and one green. I take out two balls, one blue and one white, and ask you the color of the ball left it the urn. You tell me green, not because you have seen it, but because you are accepting my premises and deducing it's color. It could be red, or any other color, for all you really "know."
And, of course, there may be no ball at all left in the urn, or 20 balls, or whatever, based on what you actually "know" by way of observation.
One Brow said: "If your purpose is to teach an alternative model to standard SR/GR, the difference is minimal. Subatomic elephants that compress atoms is also a model, but not a satisfactory one."
I guess I didn't read far enough to see that Bell's model was based on subatomic elephants.
Most, if not all, particle physicists will tell you that QM, etc., is not "truly satisfactory" in every conceivable aspect. I guess that means the entire body of theoretical work done by physicists over the last century provides merely "small bits," eh?
One Brow said: "In the twin paradox, at the end of the situation both twins are back in the same inertial reference frame and not too distant spatially. This means we can discuss who has experienced a greater passage of time relatively coherently."
It would not make any difference whether they were back in the same place; that's not the essential element here. As long as you knew which one(s) was (were) "really" moving at what rates of speed, you could say which one was "really younger" even if they had now travelled to a distance of 30 light years apart and NEVER came back together.
The essential thing, insofar as being able to give an answer, is that one has turned around, and, for that reason, you can posit that one is "really" moving and the other isn't (relative to the moving one, at least). In other words, the essential thing is that you have detected, by way of intertial changes, "real" motion.
"What you seem to be suggesting is that there is in fact an absolute, independently existing thing called "time,"
Except, I am suggesting no such thing, unless in the sense you mean length is also some independently existing thing.
If time slows, then the clock makes internal changes to slow it's own ticking rate because time has "told" it to."
If time itself slows, all the mechanisms that use time-oriented durations to slow would follow along without being told anything.
In SR the "same rate" is merely postulated, not measured.
If you limit yourself strictly to the theoritcal constructs of SR, divorced from the science, sure.
Again, you are just claiming that you "know" what you assume.
You don't think the speed of light has been tested?
Most, if not all, particle physicists will tell you that QM, etc., is not "truly satisfactory" in every conceivable aspect. I guess that means the entire body of theoretical work done by physicists over the last century provides merely "small bits," eh?
To some degree, but it has also been fruitful, providing for new ideas, new experiements, etc. Just as SR led directly to E=mc^2 and then GR, while LR has not done so.
One Brow said: "In the twin paradox, at the end of the situation both twins are back in the same inertial reference frame and not too distant spatially. This means we can discuss who has experienced a greater passage of time relatively coherently."
It would not make any difference whether they were back in the same place; that's not the essential element here.
If you want to intelligently discuss who has seen more time pass, they need to be in the same place and the same intertial reference frame. Otherwise you get different answers in different places.
As long as you knew which one(s) was (were) "really" moving at what rates of speed, you could say which one was "really younger" even if they had now travelled to a distance of 30 light years apart and NEVER came back together.
Really younger from who's point of view?
The essential thing, insofar as being able to give an answer, is that one has turned around, and, for that reason, you can posit that one is "really" moving and the other isn't (relative to the moving one, at least). In other words, the essential thing is that you have detected, by way of intertial changes, "real" motion.
Actually, the one that accelerated from the initial shared reference frame is the one that is "really" moving.
One Brow said: "Again, if you think he had a model to present as an alternative, and yet still could not achieve presenting it, you are casting upon Bell a high degree of incompetence as an instructor."
Heh, this is unbelievable. After about 5 posts back and forth on this, you are still reverting to your presumption that Bell had no model and "could not achieve presenting it."
My last post quoted portions summarizing Bell's model, and summarizing what he demonstrated (achieved) when he presented it. I have not suggested that Bell was incompetent anywhere.... well, except maybe when I indicated that his model might have been subatomic elephants, I guess.
One Brow said: "You don't think the speed of light has been tested?"
Yeah, it has, and the "tests" confirms all the predictions made by LR, ya know?
One Brow said: "If time itself slows, all the mechanisms that use time-oriented durations to slow would follow along without being told anything."
More magical mysticism, eh? How and why would a clock do any such thing? Why wouldn't it just keep on ticking at the rate it's designed to and then show the "wrong" time?
One Brow said: "Really younger from who's point of view?"
From the absolute point of view afforded by real motion, of course.
Observers, and what they see, has nothing to do with it. They both "see" the other as younger, but one is wrong, and one is right.
One Brow said: "Actually, the one that accelerated from the initial shared reference frame is the one that is "really" moving."
Yeah, that's what I said, eh?
One Brow said: "One Brow said: "If time itself slows, all the mechanisms that use time-oriented durations to slow would follow along without being told anything."
If I forget to wind a clock and it starts slowing down and then eventually stops, is this because time slowed down, then stopped? Do you really think clocks "measure time?"
"The dilation of every periodic process (like a clock function) at motion is an immediate consequence of the internal oscillation of elementary particles. The constituents of elementary particles are mass-less and orbit each other at the speed of light.
This behaviour of elementary particles was basically found by Louis de Broglie in 1923 when he detected the wave properties of elementary particles. A quantitative description was given by Paul Dirac in 1928 when he developed the famous Dirac Function of the electron. Erwin Schrödinger called this motion “Zitterbewegung.
There are good reasons to assume that elementary particles are built by two constituents. These constituents have no mass and orbit each other at the speed of light. If such an elementary particle is set into motion, but its constituents still have to maintain the speed of light in relation to a fixed reference frame, then the orbital frequency is reduced in the way predicted by the theory of relativity. This behaviour propagates to every higher structure at motion.
This means also that every clock will go slower at motion."
Well, there ya have it then, eh?
http://www.ag-physics.de/
Kinda interestin:
"The verification of Einstein’s additional bending angle of 0.87” led to instant fame and blind acceptance of his relativity theories...One serious problem with Einstein’s bending of light theory is the assumption that light will accelerate and fall closer to a gravitating body according to the equivalence principle, which would account for the first 0.87 arc secondof bend, while the rest, or 0.87 arc second, is due to the obscure warping of space. The main objection is that since light is mass less it does not accelerate but, on the contrary, slows down in a gravitational field in accordance with observations....
The bending of light in gravitational fields is better explained by Snell’s law of refraction (see Fig. 7) which is a law that was experimentally established by Willebrod Snell and theoretically by René Descartes over three hundred years ago. Snell’s law is based on the discovery that when light enters a medium which retards its velocity of propagation, such as a piece of glass or a gravitational field, it will bend at an angle determined by the combination of its change in velocity and angle of incidence. The advantage of using Snell’s law is that it eliminates both the idea that light weighs and the notion of curved space.
Light is a wave and will bend when it enters the refracting medium at an angle and if the velocity of propagation from one medium to the other varies.... The solar gravitational deflection ofelectromagnetic waves has been accurately measured during the last decade for both light and radio waves. One of the latest measurements, which was reported by Lebach et al. (1995), and which claims a precision of 0.1% agrees with Equation (35). In fact, Equation 35 yields about 1´10-5 arc second less bending angle for the Sun than Einstein’s Equation (31)."
http://www.colutron.com/download_files/chapt4.pdf
Heh, this is unbelievable. After about 5 posts back and forth on this, you are still reverting to your presumption that Bell had no model and "could not achieve presenting it."
I'm still waiting for you to present an alternative explanation for the use of the phrase "hoped to achieve" as opposed to "achieved" in the passage you asked me to examine.
My last post quoted portions summarizing Bell's model, and summarizing what he demonstrated (achieved) when he presented it.
You demonstrated Bell had some bits and pieces. AFAICT, they had not been assembled into a coherent model.
Yeah, it has, and the "tests" confirms all the predictions made by LR, ya know?
LR does not predict the speed of light in a vacuum is c. LR assumes the spped of light in a vacuum is c, just like SR, except it claims this can only be known for some "2-way speed". Were you trying to be ironic?
More magical mysticism, eh? How and why would a clock do any such thing?
You mean, not change its behavior? Because I am saying the clock does not change its behavior.
Why wouldn't it just keep on ticking at the rate it's designed to and then show the "wrong" time?
It does keep ticking at the rate it's designed to and shows the correct time that it has experienced.
One Brow said: "Really younger from who's point of view?"
From the absolute point of view afforded by real motion, of course.
When both items are in inertial environments, there is no rational basis to prefer and point of view to determine "real motion", much less an absolute one.
Observers, and what they see, has nothing to do with it. They both "see" the other as younger, but one is wrong, and one is right.
Actually, both are correct.
Yeah, that's what I said, eh?
Again, conservation of energy allows us to select a preferred inertial frame when one frame is accelerated.
Do you really think clocks "measure time?"
As much. and to the same degree, that rulers measure distance.
"The dilation of every periodic process (like a clock function) at motion is an immediate consequence of the internal oscillation of elementary particles.
I find that to be a poor description of how mechanical clocks work. The internal oscillation of elementary particles would have little effect on springs and sinning gears.
One of the latest measurements, which was reported by Lebach et al. (1995), and which claims a precision of 0.1% agrees with Equation (35). In fact, Equation 35 yields about 1´10-5 arc second less bending angle for the Sun than Einstein’s Equation (31)."
One measurement, out of all that have been done? Did Lebach's numbers disconfirm Einstein?
Lebach et al. (1995, PRL, 75, 1439) find a deflection of 0.9998 +/- 0.0008 times Einstein's prediction.
http://www.astro.ucla.edu/~wright/deflection-delay.html
One Brow said: "I'm still waiting for you to present an alternative explanation for the use of the phrase "hoped to achieve" as opposed to "achieved" in the passage you asked me to examine."
I've already given it about 4 times.
You're a teacher....you hope that method x or method y will teach object lesson z, but you know it's not always gunna work, at least not for everyone. Needless to say, it's not a guaranteed thing.
One Brow said: "You demonstrated Bell had some bits and pieces. AFAICT, they had not been assembled into a coherent model."
Wrong, absolutely wrong, but just keep tellin yourself that.
One Brow said: "LR does not predict the speed of light in a vacuum is c. LR assumes the spped of light in a vacuum is c, just like SR, except it claims this can only be known for some "2-way speed". Were you trying to be ironic?"
No, I wasn't, and we've already made a number of posts on this topic. If you think it has been proven that the speed of light is invariably c to all observers, then think again.
SR doesn't "predict" this, it POSITS it. It then "tests" it on the assumption that it's true (the very "test" presupposes the conclusion it purports to prove).
I guess you still don't see this.
One Brow said: "You mean, not change its behavior? Because I am saying the clock does not change its behavior."
Wrong
One Brow said: "It does keep ticking at the rate it's designed to and shows the correct time that it has experienced."
Wrong.
I'm inclined to think that you will never see the point or understand the question.
One Brow said: "As much. and to the same degree, that rulers measure distance."
So, then, Distance (proper noun for an existing entity), properly reified and hypostatized, who is a brother to Time, takes his powerful hands and smashes rulers closer together when Distance decides he wants to get shorter, too?
Say I have 4 clocks: 1 is accurate, best I know. 2 runs 5 minutes per hour fast. 3 runs 5 minutes slow, and one hasn't been wound. I set them up, side by side.
Does TIME then step in and force them all to measure it correctly? Does Time wind the stopped clock and force the two wrong clocks to step in line and read the "correct" time?
Or are they all just responding to mechanical internal actions involving moving gears, tightened springs, etc.? Does a clock ever even "know" if it is giving the accurate time? If it does know it, and it knows it is incorrect, does it then wind itself up, slow down its gears, or do whatever it takes to correct itself? Or does Time do all that?
One Brow says: There is a thing, called "TIME" which explains why clocks slow down when moving.
I say: There is a thing, called "DILATION" which explains why clocks slow down when moving.
Do you see the problem with my "explanation?" If so, do you see why your's has the same problem.
One Brow said: "When both items are in inertial environments, there is no rational basis to prefer and point of view to determine "real motion", much less an absolute one."
I didn't say there was. That wasn't the issue.
I said: Observers, and what they see, has nothing to do with it. They both "see" the other as younger, but one is wrong, and one is right.
You responded: Actually, both are correct.
So each twin actually is younger than the other, eh? Thank you for reintroducing the "real" twin paradox by this self-contradictory insinuation.
Now go back and tell me why all the wiki pages on the topic have to be wrong, because that's not what they say.
One Brow said: "I find that to be a poor description of how mechanical clocks work. The internal oscillation of elementary particles would have little effect on springs and sinning gears."
But time would have that effect, eh? How?
Hi, I'm from the Distance tribe, my name is True Yard.
Nice to meet you, my name is Yardstick. My purpose is to measure you.
True Yard: I hope you're flexible, because sometimes you're gunna have to shrink to half your current size, and sometimes expand to twice you size to keep up with me, because I change a lot.
Yardstick: OK, I'll watch you, and I'll just keep changing to match whatever size you become, how's that? But, wait a minute? How can I just become half my size, or twice my size?
True Yard: Don't worry, I'll squeeze and stretch your sorry ass around, as needed, kinda like my brother, True Time, does with clocks. We take care of everything.
My car has an odometer. It assumes that each time my wheel revolves once, my car will move 8 feet, because it is calibrated to assume I have a tire with a diameter of about 2.5 feet. It counts my revolutions. When I have made 660 revolutions, it tells me I have gone one mile.
For decades now, it has always been exactly 10 miles from my trailer to the front of the Post Office in Muscatel. Then, last week, I put bigger tires on my car. Then my odometer told me it was only .93 miles to the front of the post office.
So, I asked myself: Has the distance to the Post Office changed? I was puzzled at first, but then the answer became obvious:
Of course the distance changed.
Why, you ask?
Because odometers measure distance, just like clocks measure time, that's why!
My homey said: "aint, if the distance determined what your odometer would read, then the distance would have shortened the diameter of your tire so that it would still say it was 10 miles to the post office."
I said: Fool! Why would it do that? The distance has changed, caincha see? If it told me it was 10 miles, it would be wrong.
I'll leave it to you to judge who's right here. It seems that either (1) my wheel made less than 6600 revolutions to get me to the courthouse, or it didn't, and that either the number of revolutions determines what my odometer will measure to be a mile, or the distance itself tells my odometer what a mile is. Gotta be one of them things, don't it?
I decided to conduct one more empirical test on this question. I went down to my mechanic and had him put my car up on a rack, with me in it. Then I mashed down on the throttle for a spell, until my odometer said I went 10 miles. I looked down, and I was still on the same rack, in the same garage. So I told my mechanic: "Hey, guess what. Your garage just moved 10 miles, that's what!"
He said: "aint that odometer aint measurin motion, and it aint measurin miles, it's simply measurin the number of revolutions your wheel makes, that's all"
I said: Fool! The odometer measures distance, just like clocks measure time.
...you hope that method x or method y will teach object lesson z, but you know it's not always gunna work, at least not for everyone.
If I fail to get a particular student to understand a concept, the failure may be in the mind of the student or in me. If I fail to get a whole class to understand a concept, the failure is almost certainly in me. But at least know I know how you attribute the phrase. I disagree, but I don't see much prospect for either of us convincing the other.
Wrong, absolutely wrong, but just keep tellin yourself that.
Until I see something Bell developed that is described as a coherent model, I will.
If you think it has been proven that the speed of light is invariably c to all observers, then think again.
Since this is science, of course that can't be proven. It can only be observed.
SR doesn't "predict" this, it POSITS it.
As does LR, for the two-way speed. If you keep bringing this up as a reason to support LR over SR, you're just wrong, because it is as much as part of LR as it is SR.
It then "tests" it on the assumption that it's true (the very "test" presupposes the conclusion it purports to prove).
Yes, this is standard scientific procedure. You assume your generalizations are true, and try to design novel environments in which to test them. You would do this when teh paradigm is SR, LR, or something else..
I guess you still don't see this.
You mean, because we have agreed on all this before, I don't understand it? Interesting conclusion.
One Brow said: "Because I am saying the clock does not change its behavior."
Wrong
One Brow said: "It does keep ticking at the rate it's designed to and shows the correct time that it has experienced."
Wrong.
You can say "wrong" as often as you like, but that is the interpretation of SR/GR as best I understand it.
So, then, Distance (proper noun for an existing entity), properly reified and hypostatized, who is a brother to Time, takes his powerful hands and smashes rulers closer together when Distance decides he wants to get shorter, too?
Depending on who's looking at them? Distance smashed the same ruler in the same instant by 90% to one observer, 25% to a different one, and not at all to a third? No.
Or are they all just responding to mechanical internal actions involving moving gears, tightened springs, etc.?
Yes.
Does a clock ever even "know" if it is giving the accurate time?
No.
One Brow says: There is a thing, called "TIME" which explains why clocks slow down when moving.
I say: There is a thing, called "DILATION" which explains why clocks slow down when moving.
Do you see the problem with my "explanation?" If so, do you see why your's has the same problem.
Except, I'm not saying clocks slow down when moving, I'm saying clocks don't slow down when moving. *LR* says clocks slow down when moving.
You responded: Actually, both are correct.
So each twin actually is younger than the other, eh?
When referring to the twin paradox, I'll use twins. Here, as before when I don't call them twins, I was referring to two observers born near each other spatially in very different inertial environments. To aviod future confusions, I'll call them a Pat and Chris. The Pat sees Chris as being younger, Chris sees Pat as being younger, both are correct.
Let's name the twins, as well. Say Bob on the ship and Rob on the planet.
But time would have that effect, eh? How?
Time has no effect, except for passing more slowly compared to a different reference frame. The odometer stuff was completely off the point I'm trying to make, so I'm just ignoring it. Yes, I know it is the point you have been makling ad naseum, but your point is still not addressing what I understand SR to say, so its really not relevant to the SR/LR discussion.
One Brow said: "Yes, this is standard scientific procedure. You assume your generalizations are true, and try to design novel environments in which to test them. You would do this when teh paradigm is SR, LR, or something else."
No, that's not what I'm talking about. I'm talking about designing a test which presupposes your premise, and then claiming that the results prove you premise. Kinda like when you use computer simulations of probable outcomes to "prove" the assumptions you programmed into it, ya know?
One Brow said: "As does LR, for the two-way speed. If you keep bringing this up as a reason to support LR over SR, you're just wrong, because it is as much as part of LR as it is SR."
I never brought it up as a reason to prefer one over the other. These tests don't (and can't) do that.
One Brow said: "I disagree, but I don't see much prospect for either of us convincing the other."
The passages says what it says. Bell was simply trying to "achieve" the development of an open mind in his students, one which would forestall premature philosophizing about space and time.
One Brow said: "your point is still not addressing what I understand SR to say, so its really not relevant to the SR/LR discussion."
Maybe you can what SR says, and then show why my odometer point is not relevant, eh? The guy who wrote the paper on Bell (and virtually everyone else, I figure) saw the question. Do you?
You have complained about SR having no model. What is SR's model? It has none, whatsoever, it just posits magical powers to "time" and "space." But it's all purely mathematical, and senseless, except in a platonic way.
From another view, SR adopts a simplistic, "operational" definition, that is empty and tautological. It, in essence, says: A minute is what a clock measures it to be, and a yard is what a yardstick measures it to be.
They then add in the absurdity that the observer plays a role in what a yard is. If each observer "sees" the other's yardstick as foreshortened, the and his own as being the correct length, then each is right (or so you claim).
The hallucinations of a schizophrenic are, of course, "real" to him, but....
One Brow said: "Except, I'm not saying clocks slow down when moving, I'm saying clocks don't slow down when moving."
Then why would you consider it a "confirmation" of SR that two clocks will no longer agree if one has been moving? Why would they ever show different times, if one, the other, or both, didn't "slow down?" If the mechanical devices which control a clock's ticking don't change frequency, then there is no reason to think it will "keep time" at a different rate than it did yesterday.
On the other hand, if I forget to wind a clock, there is every reason to expect it to slow down and "keep time" at a faulty rate. But that has nothing whatsoever to do with "time itself." It only affects the rate at which it's internal mechanisms operate.
Likewise, why would one twin have a single less wrinkle or grey hair than his twin who is fifty years "older" if indeed his rate of aging has not slowed down?
Some aspects of this discussion are similar to an ancient debate between Protagorus, the sophist, and Socrates. Protagorus said perception is truth, because whatever a person perceives must, by definition, be true (for him at least).
Socrates claimed that perceptions can be deceiving and therefore that all perceptions could not be accepted as true.
Protagorus was right, if tautology is your sole criterion for truth, I spoze.
No, that's not what I'm talking about. I'm talking about designing a test which presupposes your premise, and then claiming that the results prove you premise.
Any results, or only a specific set of results? Are you saying that experiemnets coming from SR were claimed to support SR no matter what happened? Otherwise, I astill don't see teh difference.
Give me an example of two experiments, one in SR and one in a different field, that shows how the premise in SR is used in some different, more corrupting fashion that in, for example, biology or even Newtonian mechanics.
Bell was simply trying to "achieve" the development of an open mind in his students, ...
With regard to a particular way of interpreting relativity, for which he needed two ways of interpretation of relatively equal explanatory power.
What is SR's model?
That less time has passed for Bob than for Rob.
I never brought it up as a reason to prefer one over the other.
Then why bring it up at all? The speed of light in a vacuum is only constant until it isn't. If it is ever found not to be, SR (and LR) will e dropped.
They then add in the absurdity that the observer plays a role in what a yard is. If each observer "sees" the other's yardstick as foreshortened, the and his own as being the correct length, then each is right (or so you claim).
The hallucinations of a schizophrenic are, of course, "real" to him, but....
Reality has a way of not looking like we want it too on a regular basis.
Then why would you consider it a "confirmation" of SR that two clocks will no longer agree if one has been moving?
It means one experienced less time.
Why would they ever show different times, if one, the other, or both, didn't "slow down?"
Because the time they experience is not the same.
If the mechanical devices which control a clock's ticking don't change frequency, then there is no reason to think it will "keep time" at a different rate than it did yesterday.
I agree.
Likewise, why would one twin have a single less wrinkle or grey hair than his twin who is fifty years "older" if indeed his rate of aging has not slowed down?
By experiencing less time in which to age.
Protagorus was right, if tautology is your sole criterion for truth, I spoze.
If that is the sole criteria.
I asked: So each twin actually is younger than the other, eh?
You responded: When referring to the twin paradox, I'll use twins. Here, as before when I don't call them twins, I was referring to two observers born near each other spatially in very different inertial environments. To aviod future confusions, I'll call them a Pat and Chris. The Pat sees Chris as being younger, Chris sees Pat as being younger, both are correct.
Let's name the twins, as well. Say Bob on the ship and Rob on the planet.
It is so typical of you to completely ignore the substance of an argument and then dwell at length on some semantical quibble or technical "correction." Can you just answer the question? To wit: [Can you] now go back and tell me why all the wiki pages on the topic have to be wrong, because that's not what they say."
One Brow said: "Give me an example of two experiments, one in SR and one in a different field, that shows how the premise in SR is used in some different, more corrupting fashion that in, for example, biology or even Newtonian mechanics."
Such examples have already been given (by Van Flandern and others), based upon the method used to "synchronize" clocks. Do it one way, and you get one answer, as "predicted" by SR. Do it another way, and you get a different answer, as "predicted" (presupposed by) LR.
On the other hand if my mathematical calculations determine that the next number to come up on the keno machine will be "37," that will either happen or it won't, but it won't come up because the experiment was rigged by prearrangement (unless I set the machine to only be capable of displaying the number "37," or something).
Needless to say, the foregoing prediction is of a whole different variety than a "prediction" that adding 9 to 28 will give you 37.
What is SR's model?
That less time has passed for Bob than for Rob.
Heh, that's a "model", eh? Kinda like me sayin:
"That time has dilated more for Bob than for Rob."
Really "explains" it all, sho nuff!
One Brow said: "Then why bring it up at all? The speed of light in a vacuum is only constant until it isn't. If it is ever found not to be, SR (and LR) will e dropped."
1. LR would not necessarily be, because it doesn't posit that the speed of light is constant.
2. Once I have defined all the terms, it is logically impossible to ever "find" that 2 + 2 = 4. You cannot "find" that within SR. If you're using SR to find it, you can't, no matter how strongly certain phenomena might suggest otherwise. Bell said SR is incompatible with QM, but that this could be resolved by resorting to LR. So what? As long as you presume (and I do mean PRESUME) SR to be accurate, then any alternative solution is discarded as "impossible" a priori.
One Brow said: "It means one experienced less time."
Now, tell me, what is "time," and how is it observed, measured, etc.? You have said it is a "dimension," but that doesn't tell me anything, it just assigns a different linguistic terminology to this mysterious thing called time.
Why would they ever show different times, if one, the other, or both, didn't "slow down?"
Your answer: "Because the time they experience is not the same."
Question: Why do people change with age?
Answer: Because they get older.
Question: That's the only reason?
Answer: Yes, that's the full and complete explanation.
Question: Why do they get older?
Answer: Because time passes.
Question: That's the only reason?
Answer: Yes, that's the full and complete explanation.
Question: So time passing causes people to get older, to get wrinkles, grey hair, etc.
Answer: Exactly.
Question: So you get older because time passes, and time passes because you get older, that the idea?
Answer: You got it. Next question?
I find it somewhat ironic that you claim Feser has not convinced you of the validity of realism, but nonetheless claim that a pure abstraction like "time" has an independent existence in it's own dimension and that it "causes" clocks to keep "true" time in accordance with it.
I also hope you see that SR has not been proven, nor has the geometry associated with it. I find it strange that you reject euclidean geometry as "false," while presenting the minkowski model as true.
"If we follow Einstein’s principle about the constancy of the one-way speed of light, then we have no other choice than to assume such a kind of a 4-dimensional space-time, which is even curved in the general case....Einstein has based his theory of relativity on the assumption that the one-way speed of light is a universal constant. This speed, however, cannot be measured independently. Einstein has called his assumption a “principle”.
The philosopher Hans Reichenbach, who was one of Einstein’s best friends and a strong promoter at the early time, has stated about the assumption of a constant one-way speed of light: "This definition is essential for the special theory of relativity, but it is not epistemologically necessary."
http://www.ag-physics.de/
LR presupposes flat space and euclidean geometry, which you disparage as based upon "arbitrary" premises. But the same criticism would apply to the geometry you present as representing "reality."
In other words, I hope you are becoming more aware of how your philosophical inclinations pre-dispose you to claim x is true while z is false, and more aware of the premises upon which your assertions are based (which I don't think you have really seen when it comes to your claim that time changes clocks, and distance changes yardsticks).
It is so typical of you to completely ignore the substance of an argument and then dwell at length on some semantical quibble or technical "correction." Can you just answer the question? To wit: [Can you] now go back and tell me why all the wiki pages on the topic have to be wrong, because that's not what they say."
aintnuthin requesting directness? Will wonders never cease.
To be direct: the wiki pages do *not* say that Pat is older than Chris, nor that Chiris is older than Pat, nor that they are the same age, nor any other such nonesense. The wiki pages do say Rob will be older than Bob, which is also what I have been saying. So, I don't claim the wiki pages have to be wrong, I am afirming they are correct.
Do it one way, and you get one answer, as "predicted" by SR. Do it another way, and you get a different answer, as "predicted" (presupposed by) LR.
Actually, SR and LR give identical results to all experiments. Did you forget that?
Heh, that's a "model", eh? Kinda like me sayin:
"That time has dilated more for Bob than for Rob."
Really "explains" it all, sho nuff!
What type of mechanism should there be? What physical effect did you want to explain?
1. LR would not necessarily be, because it doesn't posit that the speed of light is constant.
LR in fact posits that the two-way speed of light is a constant. If you don't understand that, you don't understand LR at all. Whatever slows light down in one direction must speed it up in teh other direction of travel.
You cannot "find" that within SR.
That's what the experiments are for.
As long as you presume (and I do mean PRESUME) SR to be accurate, then any alternative solution is discarded as "impossible" a priori.
There is a reason to prefer SR: it has led to other findings that have also held. LR does not have this to its credit. When LR can lead to the same results, it can earn an equal place.
Now, tell me, what is "time," and how is it observed, measured, etc.?
If you can explain why this would be different in the competing theories, or relevant to an SR/LR discussion in another way, we can discuss it.
... a pure abstraction like "time" has an independent existence in it's own dimension ...
No, not independent, not in its own dimension. Is a dimension in our existence, woven into the very fabric of it.
Of course SR has not been proven, it's a scientific proposition.
LR presupposes flat space and euclidean geometry, which you disparage as based upon "arbitrary" premises. But the same criticism would apply to the geometry you present as representing "reality."
Except for the difference that SR was the lead point to many other theories that have also bveen validated, while LR has lead to nothing beyond itself.
In other words, I hope you are becoming more aware of how your philosophical inclinations pre-dispose you to claim x is true while z is false, and more aware of the premises upon which your assertions are based
I have always been aware of my preference for fruitful propositions over those that lead nowhere. I have no intention of changing that.
(which I don't think you have really seen when it comes to your claim that time changes clocks, and distance changes yardsticks).
Since you are inventing claims for me, why not something dramatic?
One Brow said: "I am afirming they are correct."
Then you are affirming that the one who is "really" moving is "really" younger, notwithstanding that each one sees the other as being younger. I.e., one is right, and one is wrong, which is all I said. Your response was that both are correct--not what wiki was sayin.
One Brow said: "LR in fact posits that the two-way speed of light is a constant. If you don't understand that, you don't understand LR at all. Whatever slows light down in one direction must speed it up in teh other direction of travel."
Who said anything about the two-way speed? Certainly not you, in the post I responded to.
One Brow said: "Actually, SR and LR give identical results to all experiments. Did you forget that?"
According to Van Flandern (and others I have read):
"Technical note: Measuring the one-way speed of light requires two clocks, one on each end of the path. If the separation of the clocks is known, then the separation divided by the time interval between transmission and reception is the one-way speed of the signal. But measuring the time interval requires synchronizing the clocks first. If the Einstein prescription for synchronizing clocks is used, then the measured speed must be the speed of light by definition of the Einstein prescription (which assumes the speed of light is the same in all inertial frames). If some other non-equivalent synchronization method is used, then the measured speed of the signal will not be the speed of light. Clearly, the measured signal speed and the synchronization prescription are intimately connected."
http://www.metaresearch.org/cosmology/gps-relativity.asp
This has not been, and so far as we know, cannot be directly tested, so, right, it isn't a "test result." But what any given tests "shows" (i.e., how the results are interpreted) is dependent upon the premises. Using a synchronization method which dictates a given conclusion (because it is presupposed in the experiment design itself) does not "test" anything.
"
Then you are affirming that the one who is "really" moving is "really" younger,
Are you referring to Pat and Chris (in which case the article says nothing that can even be interpreted that way) or Bob and Rob (in which case you can at least pull that meaning out of the article, by interpreting changing inertial frames as "really moving")?
notwithstanding that each one sees the other as being younger. I.e., one is right, and one is wrong, which is all I said.
At no time is one "right" and the other "wrong" unless you assume some fictional simultaneity. Each sees what is correct from their point of view.
Your response was that both are correct--not what wiki was sayin.
The wiki pages do not identify either Bob or Rob as being "correct" or "wrong" at any time. It just describes what they see. Neither sees the other exactly as they are in the fictional simultaneity.
Who said anything about the two-way speed? Certainly not you, in the post I responded to.
Not in that particular post? Shall I mention it in every post for you?
According to Van Flandern
Nothing in that disputed that LR posits c as the two-way speed of light or that no experiemnt can distinguish SR and LR directly.
One Brow said: "There is a reason to prefer SR: it has led to other findings that have also held."
Such as? And in what way does it "lead" to them in a way that LR would not?
LR does not have this to its credit. When LR can lead to the same results, it can earn an equal place.
According to Bell, LR would be compatible with QM while SR is fundamentally incompatible. Is this a "result?"
One Brow said: "Each sees what is correct from their point of view."
Like Protagoras said many centuries ago, eh? But what is that sayin? It just says, tautologically, that "I see what I see," best I can tell.
One Brow said: "Except for the difference that SR was the lead point to many other theories that have also bveen validated, while LR has lead to nothing beyond itself."
For about the 20th time in this discussion (forget all our others) you make broad, absolute claims that are based upon nothing more than your prejudices. Your air of cocksure assertion may suffice to convince some, but I look for a little more than that.
To begin with, LR led to SR. Einstein "stole" the Lorentz-Fitzgerald transformations whole cloth.
One Brow said: "I have always been aware of my preference for fruitful propositions over those that lead nowhere. I have no intention of changing that."
You may be kidding yourself about your grounds for deciding what is "fruitful." It could just come down to whatever theory you have been assured in favored by most scientists.
At times you insist that only a model with a mechanisms can satisfy your refined tastes. Next thing I know, you call the word "time" a model and a mechanism. I have my own mechanism, ya know? Wherever you use the word "time" to explain it all, I just use "the power." Works just as well.
One Brow said: "Nothing in that disputed that LR posits c as the two-way speed of light or that no experiemnt can distinguish SR and LR directly.
OK, and? Nothing I said disputed either of those propositions either, and that had nothing to do with my reason for quoting him.
"Now, tell me, what is "time," and how is it observed, measured, etc.?
One Brow said: "If you can explain why this would be different in the competing theories, or relevant to an SR/LR discussion in another way, we can discuss it."
Feel free to discuss or refrain from discussing anything you want, but this question is really my only reason for getting into this SR/LR discussion to begin with. This is where the ontological and philsophical elements come in, and that was where this thread actually started (with Feser, ya know?).
One Brow said: "Are you referring to Pat and Chris (in which case the article says nothing that can even be interpreted that way)..."
Says nuthin? Really? How ya figure? Because they don't explicitly refer to "Pat" and "Chris," that it?
"...Bob and Rob (in which case you can at least pull that meaning out of the article, by interpreting changing inertial frames as "really moving")?"
Exactly. "Changing reference frames" is just an obscure and roundabout way of saying one is really moving. And it is the one who is "really" moving that is "really" younger, whether there has been any change of reference frames or not.
One Brow said: "LR in fact posits that the two-way speed of light is a constant. If you don't understand that, you don't understand LR at all. Whatever slows light down in one direction must speed it up in teh other direction of travel."
Do you even realize that you contradict yourself with this post?
Just in case you don't, your original statement was this: "The speed of light in a vacuum is only constant until it isn't. If it is ever found not to be, SR (and LR) will e dropped."
Assuming the light is "in a vacuum" on each leg of the trip, it is definitely not "constant" according to LR.
I think this guy poses the choice pretty clearly:
"Special Relativity comprises three phenomena occurring at fast motion:
(1) Physical objects contract
(2) Clocks change their speed (and so their time indications)
(3) Masses increase
And: Every measurement of the speed of light ‘c’ has the same result. This can be taken as the origin of the above phenomena (Einstein). Or, the other way around: The measured constancy of the speed of light is the consequence of the these phenomena (Lorentz).
1. The measurment (constancy) is the "origin" of the phenomena,
versus
2. The constancy of measurement is the "consequence" of the phenomena.
http://www.ag-physics.de/
The paper this is excerpted from below is rather long and somewhat technical. I haven't read it all, and don't pretend be able to understand it all even if I did. That said, among it's claims are:
"As we approach the twenty-first century, the tools are becoming readily available to test directly the concepts of time dilation versus clock retardation and length contraction. These tools come in three varieties: extremely stable periodic cosmological sources such as millisecond pulsars, sophisticated earth-orbit timing and relay equipment such as the Global Positioning Satellite (GPS) system, and ultra-sensitive astrometric resolution systems such as....
Thus we see that an atomic clock that has been placed in motion is susceptible to a lower frequency, and thus accumulates less time, than a clock that remains stationary for any initial rest frame of reference we choose...It is extremely important to realize that time does not actually slow down due to this motion. Since cesium atoms of a given velocity require a specific frequency to reach the excited state, so atoms accelerated to a different velocity relative to the first require a different frequency, as measured in the reference frame of the first; shifted to the red according to the magnitude of the velocity by the factor g-1. Since the frequency is lower, it takes more time for a fixed number of cycles to occur. With seconds in these clocks being defined as the length of time required for a specific number of cycles to occur, the moving clock slows down--more physical time is required for a given "second" to pass in the moving clock...
Most importantly, however, it must be stressed again that time itself has not slowed down. Only the arbitrary units of measure with which we choose to mark time have slowed, whether atomic processes, frequency changes or molecular reactions. The distinction is important. In the relativistic model, clocks slow down because time itself slows down. No "mechanical" description is provided as to why the clocks slow, and, if it were, the effect would be additive. Quentin Smith has argued at length and quite successfully in Language and Time from a philosophical standpoint that "metaphysical time is the only time in the actual world and that it is the only time in any possible world in which there is time."...
[continued in next post]
...another round-the-world clocks experiment is currently in progress, the Global Positioning Satellite System (GPS). In this system of satellites and earth stations, the timing differential between clocks is compared real time, and is, in fact, the basis of the system...We first note that, since all these satellites have the same velocity with respect to the hypothetical earth centered clock, all will have received the same velocity pre-correction prior to launch, thus all claocks have been calibrated identically prior to launch. After launch, it is found that all clocks are keeping synchronous time as anticipated, and they are able to signal each other accordingly. But now let us consider the special relativistic view on a clock to clock basis, not reflecting through the hypothetical earth center frame...
Thus even though the GPS clocks are able to be synchronized using the so-called special relativistic time dilation formula as referred through the center-of-earth frame, once in their actual orbits the pre-correction should not work consistently regarding signals passed between any two relatively moving clocks...This indicates that, while the equations of special relativity produce correct results to a large variety of problems to which they are applied, there is something fundamentally wrong with the underlying assumptions that were used to develop those equations and with their assumed realm of validity of application.
http://renshaw.teleinc.com/papers/london1/london1.stm
I don't post this as a prelude to debating the physics involved. This guy seems to do a fair job of contrasting the difference in the SR and LR views by reference to their underlying assumptions. The question remains: Are the phenomena in question the "origin" of the measurements, or are the measurements the consequence of the phenomena?
Meant to say: The question remains: Are the measurements in question the "origin" of the phenomena, or are the measurements the consequence of the phenomena?
One Brow said: "There is a reason to prefer SR: it has led to other findings that have also held."
Such as?
The correct calculation for mass-energy equivalance and GR, for starters.
And in what way does it "lead" to them in a way that LR would not?
You can find the details on the web, if you so desire. I have forgotten a few of them and am not inclined to look them up right now.
According to Bell, LR would be compatible with QM while SR is fundamentally incompatible. Is this a "result?"
I believe he thought LR might be compatible, not would be, and yes, that is an important consideration as well.
To begin with, LR led to SR. Einstein "stole" the Lorentz-Fitzgerald transformations whole cloth.
If LR is nothing by the transformations, it would not be a different metaphysical interpretation. Einstein developed a theory where the accepted equations are derivable.
You may be kidding yourself about your grounds for deciding what is "fruitful." It could just come down to whatever theory you have been assured in favored by most scientists.
If LR is nothing but the transformations, it would not be a different metaphysical interpretation. Einstein developed a theory where the accepted equations are derivable, but it was not based in LET (which later became LR). The transformations also exieted before LET.
Next thing I know, you call the word "time" a model and a mechanism.
"Time" in and of itself is neither the model nor the mechanism. Experiencing less time is the model.
OK, and? Nothing I said disputed either of those propositions either, and that had nothing to do with my reason for quoting him.
So, you brought in the impossibility of testing the one-way speed of light just for fun? OK.
"Now, tell me, what is "time," and how is it observed, measured, etc.?
Since you feel this questions is important after all, fine.
Time is a dimension, in the same way that length is. We exist in spacetime, which has three length dimensions that are "free" in a particular way (you can express this freedom mathematically with tensors, but I have not looked at them in 25 years or so)., and another time dimension that is not "free", so that nothing is ever in the same time twice. However, because of the way that time is not free, you can travel along it differently, just like you take different physical paths, and unlike the physical paths, the time paths do not need to sum up equally to have an equal change in coordinates. Any talk of time slowing or dilating is metaphorical/relative, and refers to what one observer sees of another observer. Using the geometrical interpretation of GR, you would say that Bob uses a path that travels less in the time dimension than Rob to arrive at the same spacetime location. It's not that time nor travel change the clocks (that would be an LR interpretation), there is simply less time experienced.
Says nuthin? Really? How ya figure? Because they don't explicitly refer to "Pat" and "Chris," that it?
Because there are fundamental differences between the Pat/Chris situation and the Bob/Rob situation, and the twin paradox is not remotely applicable to Pat/Chris.
Exactly. "Changing reference frames" is just an obscure and roundabout way of saying one is really moving.
I understand you interpret it that way, and this is not fundamentally opposed to what the article says, but the article does not make that interpretation.
One Brow said: "LR in fact posits that the two-way speed of light is a constant. If you don't understand that, you don't understand LR at all. Whatever slows light down in one direction must speed it up in teh other direction of travel."
Do you even realize that you contradict yourself with this post?
You think describing what LR says is contradicting myself? Or, are you saying I gave a description of LR previously that contradicts this description?
Just in case you don't, your original statement was this: "The speed of light in a vacuum is only constant until it isn't. If it is ever found not to be, SR (and LR) will e dropped."
Assuming the light is "in a vacuum" on each leg of the trip, it is definitely not "constant" according to LR.
The two-way speed of light in LR is c, and this is as fundamental to LR as it is to SR. If light travels at a speed of c + k in one direction, it must travel at c(c+k)/(c+2k) (no, *not* at c-k) in the other direction to preserve the two-way speed as c. Anything that effects light in one direction effects it to a different magnitude in the opposite direction.
I think this guy poses the choice pretty clearly:
Yes, but imprecisely.
"Special Relativity comprises three phenomena occurring at fast motion:
(1) Physical objects contract
(2) Clocks change their speed (and so their time indications)
(3) Masses increase
It's not really clocks changing their speed, physical objects contracting, or mass increasing. That is the LR interpretaton, not SR.
Thus even though the GPS clocks are able to be synchronized using the so-called special relativistic time dilation formula as referred through the center-of-earth frame, once in their actual orbits the pre-correction should not work consistently regarding signals passed between any two relatively moving clocks...
Unless there is also a programmed computer on board to adjust for the effects.
The question remains: Are the measurements in question the "origin" of the phenomena, or are the measurements the consequence of the phenomena?
Or perhaps is there a fundamental idea that encompasses both?
One Brow said: "The correct calculation for mass-energy equivalance and GR, for starters."
As I have already pointed out, the proposition that e=mc2 preceded Einstein. It is also my understanding that the notion of "spacetime" in GR is significantly different from the notion of "spacetime" in SR. In what sense did one "lead to" the other? In the same sense that LR led to SR?
I have seen it claimed, many times, that relativistic "mechanics" can be replaced with "relational" mechanics, based on traditional notions of relativity, without losing any explanatory power. It is dubious to assume that one, and only one, particular interpretation of a purely mathematical formulation can (or will) lead to necessary consequences that an alternate interpretation would/could not lead to. Whether you tell me that "x" + 7 = 10 or that 3 + x = 10 is irrelevant. The solution will be the same, as will all the relevant terms.
One Brow said: "Because there are fundamental differences between the Pat/Chris situation and the Bob/Rob situation, and the twin paradox is not remotely applicable to Pat/Chris."
Such as? And how do these things change the fundamental underlying principles involved? I can say that a bulldog is fundamenally different from a labador retriever, but they're both still dogs, ya know?
One Brow said: "It's not that time nor travel change the clocks (that would be an LR interpretation), there is simply less time experienced."
Very easy to say, and very easy to treat time as a dimension for mathematical purposes, but what does it mean? I don't think you answered these questions"
1. What is time? Is it "real," having an independent existence in some "realm," or is it merely an abstract concept?
2. Is time observable?
3. How is time meaured?
If I say it take "one year" for the earth to make one complete revolution around the earth, then what is "one year?" Is that time? If not, what is it?
Meant to say "around the sun" (not earth), of course. If the earth could somehow be speeded up in its orbit, would "one year" be shorter? Yeah, it seems so. Would that now be a "real year," because time has changed? Or does what I calculate the year to be depend on the speed of the earth, rather than "time itself?"
One Brow said: "The two-way speed of light in LR is c, and this is as fundamental to LR as it is to SR."
Agreed, but how does that make the speed of light in a vacuum "constant?"
If I say a student "constantly" get a B grade, and if, in fact, he gets a B in every class he takes, that would be accurate.
But if I take another students who gets a variety of grades in different classes, some A, some B, some C, some D, and so on, it would be inaccurate to say he "constantly gets B's" just because he has a B average, all said and done.
As I have already pointed out, the proposition that e=mc2 preceded Einstein.
Actually, you pointed out: "I have read that E = 3/4 MC2 was formulated in 1882". This seems to have been almost correct.
From wiki:
"Following Thomson and Searle (1896), Wilhelm Wien (1900), Max Abraham (1902), and Hendrik Lorentz (1904) ... The formula of the mass–energy-relation given by them was m = (4 / 3)E / c2. ... In July 1905 ... Poincaré was able to explain the reason that the electromagnetic mass calculations always had a factor of 4/3."
http://en.wikipedia.org/wiki/Mass-energy_equivalence
It is also my understanding that the notion of "spacetime" in GR is significantly different from the notion of "spacetime" in SR. In what sense did one "lead to" the other? In the same sense that LR led to SR?
There are basically two defining metaphysical ideas in SR: arbitrariness of intertial basis choice and constancy of light. GR adopts both of these, and adds in not being able to tell the difference between acceleration and gravity.
It is dubious to assume that one, and only one, particular interpretation of a purely mathematical formulation can (or will) lead to necessary consequences that an alternate interpretation would/could not lead to.
Unless, between the two theories, one has a metaphysic that ties directly to the consequences that the alernate interpretation does not share.
One Brow said: "Because there are fundamental differences between the Pat/Chris situation and the Bob/Rob situation, and the twin paradox is not remotely applicable to Pat/Chris."
Such as?
Neither Pat nor Chris undergoes acceleration.
And how do these things change the fundamental underlying principles involved? I can say that a bulldog is fundamenally different from a labador retriever, but they're both still dogs, ya know?
Pat and Chris will, at most, be within a reasonable spatial separation one time only. As their spatial separation increses, any notion of simultaneity becomes increasingly relativistic. Bob and Rob start and end not only in the same intertial environments, but also in about the same location, so simultaneity is more meaningful.
One Brow said: "Or perhaps is there a fundamental idea that encompasses both?"
Well, I suppose there is, if you want to become monistic and extremely general about it. One cannot imagine a coin without two different sides (3 if you count the edge as a "side"), but I can still say one concept ("coin") encompasses all 3.
Likewise, I can say that without "time" there is no motion, no change, no anything, and that therefore time causes all things and is the ultimate source of all things. Time is God. This would be meaningless as a practical matter, but perhaps true as a conceptual matter--so long I insist on maintaining a very rigid and extremely general perspective.
One Brow said: "Poincaré was able to explain the reason that the electromagnetic mass calculations always had a factor of 4/3."
Yes, I have already quoted that very passage myself. When I did, I also quoted earlier physicists who said E = mc2
Very easy to say, and very easy to treat time as a dimension for mathematical purposes, but what does it mean? I don't think you answered these questions"
1. What is time? Is it "real," having an independent existence in some "realm," or is it merely an abstract concept?
Is length real? If I say Deron Williams is 6'3" tall, does that have independent existence in a realm, or is it merely an abstract concept?
Length and time are distances between points in spacetime.
2. Is time observable?
It has no visual manisfestation.
3. How is time meaured?
As the distance between two points.
If I say it take "one year" for the earth to make one complete revolution around the sunthen what is "one year?" Is that time?
Yes.
Or does what I calculate the year to be depend on the speed of the earth, rather than "time itself?"
Much like meters are different from inches.
Agreed, but how does that make the speed of light in a vacuum "constant?"
The two way speed is constant.
But if I take another students who gets a variety of grades in different classes, some A, some B, some C, some D, and so on, it would be inaccurate to say he "constantly gets B's" just because he has a B average, all said and done.
Here, the student does not have a B average, his average is 85 exactly. If you check his grade on the first day of class, the second day, the third day, etc., all the way through the semester, it is exactly 85, never higher or lower. That's pretty constant.
One Brow said: "Neither Pat nor Chris undergoes acceleration."
And how would that change the proposition that whoever is "really" going faster is the one who is "really" aging? As you yourself have noted, acceleration is not necessarily important to the wiki answer (depending on whether you want to use a GR or SR answer).
Of course "acceleration" is important to both answers, in the sense that it gives an answer to the question of who is "really" moving. If you can't determine that, you can't give the answer you do (or any other answer). But none of my statements were conditioned on being able to empirically determine which was moving. I simply said that whoever was "really" moving (or really moving faster than the other) would be younger, which is exactly what both SR and GR would predict, best I can tell.
We've been through this before, but again, what one knows is not the equivalent of what is.
Suppose I tell you (truthfully) that I have a jar in the next room with jelly beans in it. I then ask you how many jelly beans are in the jar. You say (honestly) "I have no idea."
Or you can guess 12, or 783, it wouldn't have any affect on how many jelly beans are actually in the jar, whether you "know," or have any way of determing, that number or not.
One Brow said: "Here, the student does not have a B average, his average is 85 exactly. If you check his grade on the first day of class, the second day, the third day, etc., all the way through the semester, it is exactly 85, never higher or lower. That's pretty constant."
What do you mean by "here?" The case where light travels at one speed on one leg, and at a different speed on the other? A two-way speed is nothing more than an average (even if the two legs are identical). Are you just playing words games, or do you really not understand the difference between an average result and a single result?
One Brow said: "3. How is time meaured?
As the distance between two points.
So time is now a distance, eh? You mean in the sense that a "lightyear" is a distance, or what?
I asked: "Or does what I calculate the year to be depend on the speed of the earth, rather than "time itself?"
You answered: "Much like meters are different from inches."
I have no idea how this even addresses, let alone answers, the question. Can you be more specific?
One Brow said: "There are basically two defining metaphysical ideas in SR: arbitrariness of intertial basis choice and constancy of light. GR adopts both of these, and adds in not being able to tell the difference between acceleration and gravity."
Well, I wasn't limiting it to "metaphysical" ideas, although you can call a lot of things "metaphysical" if you want. SR was based upon Euclidean geometry (flat space) and a newtonian idea of a "straight line." Even within the mathematics of GR there is room for different, though equally valid, interpretations (geometrical vs field, for example). My point was simply that GR was in no way implied by (deduced from) SR, and it didn't "lead" to it in that sense.
If I call one complete revolution around the sun a "year," what am I measuring? Time itself? Or just a change in apparent motion (relative to the fixed stars)?
If I assume that every year is of the same duration, and hence that every year is equal in that respect, then I might lean toward calling it a unit of time. Then, when I talk about 3 years, or a decade, or a century, I am talking about multiple occurences of an event based on motions which happen, I think, with a constant frequency.
On the other hand, if, due to comparison with other events, I am convinced that the duration of each revolution is irregular and arbitary (one revolution make take 12 months, the next 3 months, the next 6.73 months, etc.), I am unlikely to call one revolution a measurement of duration. I will call it what it really is, a change in my observations of relative motion. I will call it a "revolution," rather than a "year."
But either way, I am not measuring "time itself" (whatever that is). Like the odometer on my car, I am merely counting revolutions, a motion-based phenomenon, whether of regular duration and/or regular "distance" or not.
I guess if I take the SR approach, then I say a year is a year, regardless of distance travelled or duration consumed, and that one revolution is "time itself."
Likewise, I can assume my odometer simply measures "distance" without regard for consistent duration (time). Whether I am travelling 1 mph or 60 mph, it will still tell me when I have gone 1 mile. But this conclusion is itself a deduction, based on certain premises, because, even then, my odometer merely counts revolutions (again, a motion-based phenomena), not distance per se. If I change my tire diameter, the distance which my odometer formerly told me was a mile will be different that the distance it thereafter tells me is a "mile." It is counting revolutions, not measuring miles.
Again, if I take the SR approach to distance, then I guess I would say that one revolution of my wheel "is distance itself," and that a mile is therefore whatever my odometer tells me it is, irrespective of tire diameter.
A little elaboration on the euclidean geometry of SR, which, in GR, is merely local, rather than "global."
"The postulates of special relativity -- The Existence of Globally Inertial Frames"
Statement: "There exist global spacetime frames with respect to which unaccelerated objects move in straight lines at constant velocity".
A frame in which unaccelerated objects move in straight lines at constant velocity is called an inertial frame.
Implicit in the assumption of the existence of globally inertial frames is the assumption that the geometry of spacetime is flat, the geometry of Euclid.
The postulate that globally inertial frames exist is carried over from classical mechanics (Newton's first law of motion)."
Contrasted with GR:
"A globally inertial frame is an inertial frame that covers all of space and time....In general relativity, this postulate is replaced by the weaker postulate that local (not global) inertial frames exist. A locally inertial frame is one which is inertial in a `small neighbourhood' of a spacetime point. In general relativity, spacetime can be curved."
http://casa.colorado.edu/~ajsh/sr/postulate.html
One Brow said: "There are basically two defining metaphysical ideas in SR: arbitrariness of intertial basis choice and constancy of light. GR adopts both of these, and adds in not being able to tell the difference between acceleration and gravity.""
According to this same guy, the "constancy of light" is not "carried over" to GR:
"In general relativity, arbitrarily weird coordinate systems are allowed, and light need move neither in straight lines nor at constant velocity with respect to bizarre coordinates (why should it, if the labelling of space and time is totally arbitrary?). However, general relativity asserts the existence of locally inertial frames, and the speed of light is a universal constant in those frames."
One further observation about what's Einstien's principle of special relativity "leads to" (and what leads to it):
"It is to be noted that the Principle of Special Relativity does not imply the constancy of the speed of light, although the postulates are consistent with each other. Moreover the constancy of the speed of light does not imply the Principle of Special Relativity, although for Einstein the former appears to have been the inspiration for the latter."
And how would that change the proposition that whoever is "really" going faster is the one who is "really" aging?
It means there can be no single answer to the question without specifying a reference frame first. "Really" is not a reference frame.
As you yourself have noted, acceleration is not necessarily important to the wiki answer (depending on whether you want to use a GR or SR answer).
True, for Bob and Rob it does not especially affect the answer in terms of the size of the difference. It is important only to the notion that Bob is moving.
Of course "acceleration" is important to both answers, in the sense that it gives an answer to the question of who is "really" moving. If you can't determine that, you can't give the answer you do (or any other answer).
No, even if you assume Rob is moving and Bob is stationary, the answer is still that Bob will be younger. This comes from a "time slippage" in the not-conserving framework, remember?
But none of my statements were conditioned on being able to empirically determine which was moving. I simply said that whoever was "really" moving (or really moving faster than the other) would be younger, which is exactly what both SR and GR would predict, best I can tell.
In SR (and GR, as I understand it), the question of whether Pat or Chris is "really" moving does not even make sense.
Suppose I tell you (truthfully) that I have a jar in the next room with jelly beans in it. I then ask you how many jelly beans are in the jar. You say (honestly) "I have no idea."
Or you can guess 12, or 783, it wouldn't have any affect on how many jelly beans are actually in the jar, whether you "know," or have any way of determing, that number or not.
In SR, the number of beans will change when you move to different points in the next room, in the doorway, standing by the jar, etc.
What do you mean by "here?" The case where light travels at one speed on one leg, and at a different speed on the other? A two-way speed is nothing more than an average (even if the two legs are identical). Are you just playing words games, or do you really not understand the difference between an average result and a single result?
As you have read and quoted over and over, there is no single result. We have no way to measure the one-way speed of light. Every grade we see in an 85. Further, if light is exceeds c on one direction, it must be slowed by a smaller amount in the opposite direction to make this average of c happen. So, whatever supposedly affects the speed of light does so unequally in the two directions.
One Brow said: "'3. How is time meaured?' As the distance between two points."
So time is now a distance, eh? You mean in the sense that a "lightyear" is a distance, or what?
A lightyear would be a distance in length dimension, not a time dimension. Time is measured by the distance between two points in the time dimension.
I asked: "Or does what I calculate the year to be depend on the speed of the earth, rather than "time itself?"
You answered: "Much like meters are different from inches."
I have no idea how this even addresses, let alone answers, the question. Can you be more specific?
A year is defined as the distance in time is takes for the earth to circle the sun. If yo ushorten that distance in time, you change the length of the year by definition, just as a meter is a different length than an inch by definition.
My point was simply that GR was in no way implied by (deduced from) SR, and it didn't "lead" to it in that sense.
In that sense, OK.
If I call one complete revolution around the sun a "year," what am I measuring? Time itself?
If you measure the distance from your stove to your refrigerator, are you measuring length itself?
Or just a change in apparent motion (relative to the fixed stars)?
Are you measuring motion when you measure the distance from the stove to the refrigerator?
I guess if I take the SR approach, then I say a year is a year, regardless of distance travelled or duration consumed, and that one revolution is "time itself."
Actually, that is much more of an LR approach. It's funny how you keep doing that.
Again, if I take the SR approach to distance, then I guess I would say that one revolution of my wheel "is distance itself," and that a mile is therefore whatever my odometer tells me it is, irrespective of tire diameter.
Doesn't sound like SR.
Implicit in the assumption of the existence of globally inertial frames is the assumption that the geometry of spacetime is flat, the geometry of Euclid.
Actually, this works equally well in Minkowskian space. Inertial frames aren't straight lines anymore, but they work just fine.
According to this same guy, the "constancy of light" is not "carried over" to GR:
If you choose arbitrarly weird coordinates for SR, the same thing happens. The global inertail frames are not essential to SR. GR is an extension of SR, there is nothing allowed in GR and forbidden to SR.
"It is to be noted that the Principle of Special Relativity ...
Is one of four postulates mentioned.
One Brow said: "No, even if you assume Rob is moving and Bob is stationary, the answer is still that Bob will be younger. This comes from a "time slippage" in the not-conserving framework, remember?"
This isn't right. If you reverse the presumption about who is moving, then the earth-twin will be the one who is involved in the "turn-around."
"The issue in the general relativity solution is how the traveling twin perceives the situation during the acceleration for the turn-around. This issue is well described in Einstein's twin paradox solution of 1918.[7] In this solution it was noted that from the viewpoint of the traveler, the calculation for each separate leg equals that of special relativity, in which the Earth clocks age less than the traveler. For example, if the Earth clocks age 1 day less on each leg, the amount that the Earth clocks will lag behind due to speed alone amounts to 2 days. Now the accelerated frame is regarded as truly stationary, and the physical description of what happens at turn-around has to produce a contrary effect of double that amount: 4 days' advancing of the Earth clocks. Then the traveler's clock will end up with a 2-day delay on the Earth clocks, just as special relativity stipulates."
It is the "traveler's" clock which is adjusted.
One Brow said: "Actually, this works equally well in Minkowskian space. Inertial frames aren't straight lines anymore, but they work just fine."
Read it closely (and the contrast between the geometry of SR and that of GR). I think you are confusing the geometry (euclidean) used by minkowski to create a model for SR with the riemannian geometery developed in connection with GR.
But here's the part I'm really interested in exploring. I can't comprehend what you're saying about time now being a "distance" in the "time dimension."
You say: "A year is defined as the distance in time is takes for the earth to circle the sun. If yo ushorten that distance in time, you change the length of the year by definition."
Using the notion of "distance" to "define" time just makes it all the more incomprehensible. Does "distance in time" just mean "duration," here, is that it? You must be taking some intermediate mental steps, which you are not disclosing" to reach your conclusions. Nobody I know defines a year in terms of distance (whether in time, or otherwise).
It is essentially one revolution. What that revolution says about "time" is strictly a secondary notion. The question is (and was): what are we measuring? We are simply observing our relationship to the fixed stars and comparing recurring positions. One revolution is one year. If we count 365 1/4 rotations of the earth (another phenonemon involving relative motion) during the same period then we have 365 days in a year, etc.
We are observing and counting periods of recurring positions resulting from motion, not time. Time is a conceptual construct which we derive from the experience of motion.
As I said: "If I assume that every year is of the same duration, and hence that every year is equal in that respect, then I might lean toward calling it a unit of time. Then, when I talk about 3 years, or a decade, or a century, I am talking about multiple occurences of an event based on motions which happen, I think, with a constant frequency.
On the other hand, if, due to comparison with other events, I am convinced that the duration of each revolution is irregular and arbitary (one revolution make take 12 months, the next 3 months, the next 6.73 months, etc.), I am unlikely to call one revolution a measurement of duration. I will call it what it really is, a change in my observations of relative motion. I will call it a "revolution," rather than a "year."
Do you disagree with this statement?
One Brow said: "In SR, the number of beans will change when you move to different points in the next room, in the doorway, standing by the jar, etc."
So SR affect quantities of objects now, too?
One Brow said: "In SR (and GR, as I understand it), the question of whether Pat or Chris is "really" moving does not even make sense."
I thought we had explicity agreed otherwise in prior posts. The question "makes sense," it just can't be answered. The fact that you don't have an answer to a question doesn't make the question itself "senseless," sorry if that disappoints you.
One Brow said: "GR is an extension of SR, there is nothing allowed in GR and forbidden to SR."
Really?
"Special relativity is founded) on the basis of the law of the constancy of the velocity of light. But the general theory of relativity cannot retain this law. On the contrary, we arrived at the result that according to this latter theory the velocity of light must always depend on the co-ordinates when a gravitational field is present." (Albert Einstein)
GSR also allows for faster than light travel, eh?:
"General relativity was developed after special relativity to include concepts like gravity. It maintains the principle that no object can accelerate to the speed of light in the reference frame of any coincident observer. However, it permits distortions in spacetime that allow an object to move faster than light from the point of view of a distant observer. One such distortion is the Alcubierre drive, which can be thought of as producing a ripple in spacetime that carries an object along with it...General relativity also agrees that any technique for faster-than-light travel could also be used for time travel. This raises problems with causality. Many physicists believe that the above phenomena are in fact impossible, and that future theories of gravity will prohibit them."
http://en.wikipedia.org/wiki/Faster-than-light
One Brow said: "... there is no single result. We have no way to measure the one-way speed of light."
I have no way to measure the size of the universe. Does that mean the universe "has no size?" I have no way to know the exact number of people in the state of Illinois at this very moment. Does that mean there are no people here, or that there is no such number? You seem to consistently equate what you can or do know to what can possibly be. A fundamental fallacy.
One Brow said: "if light is exceeds c on one direction, it must be slowed by a smaller amount in the opposite direction to make this average of c happen."
Exactly, in which case the speed of light would not be constant, which was the only issue in question.
It's kinda funny how one's assumptions are so quickly percieved as indisputable fact on the basis of circular reasoning, eh?
"the meter was intended to equal 10-7 or one ten-millionth of the length of the meridian through Paris from pole to the equator. However, the first prototype was short by 0.2 millimeters because researchers miscalculated the flattening of the earth due to its rotation...in 1983 the CGPM replaced this latter definition by the following definition:
"The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.""
So, what has happened here? When it started out, speed was time divided by distance. In other words, you had to know the distance (and the time) in order to determine the speed.
Then Einstien simply "posited" that the speed of light is constant in a vacuum. Since this quotient MUST (by postulate) be constant, then we know longer need to know both the time and distance to know speed. But, funny thing is, we needed to know the distance to calculate the speed to begin with, so it all gets circular---to the point where now there are trying to define distance in terms of a concept (speed) which presupposes that distance has already been defined and determined.
It's also kinda funny that this was supposedly done in order to "reduce the uncertainty with which the meter may be realized." Is there "certainty" about what a "second" is? Doesn't that measure of time itself constantly change with speed according to SR? Of course we always have ABSOLUTE CERTAINTY about what distance/time is, because we have assumed it, a priori.
I'm really surprised that they didn't just go ahead and define what a "second" is by stating it's relationship to a meter with respect to the ABSOUTELY CERTAIN speed of light (as defined above).
"The unit of time, the second, was defined originally as the fraction 1/86 400 of the mean solar day. The exact definition of "mean solar day" was left to astronomical theories. However, measurement showed that irregularities in the rotation of the Earth could not be taken into account by the theory and have the effect that this definition does not allow the required accuracy to be achieved." So, now what?
"The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom."
Well, that clears everthing up, and provides certainty, I expect. Nothing presupposed there about how the "the transition between the two hyperfine levels of the ground state of the cesium 133 atom" occurs, I'm sure.
Either way, they are defining a "second" as a "duration" also said to be a "unit of time." I don't see anything in there about dimensions or distances, for some reason.
"However, measurement showed that irregularities in the rotation of the Earth could not be taken into account by the theory and have the effect that this definition does not allow the required accuracy to be achieved."
I guess these fools don't even know that "irregularities" are totally irrelevant to time, eh? If the earth rotates irregularly, that just means a second is changing, why can't they see that?
Does it concern you at all, Eric, that you scoff at Feser for thinking that euclidean geometry, (a "formal system") can tell you anthing about truth, but then proceed yourself to proclaim the "truth" about space, based upon the application of riemannian geometry?
I asked: "It's also kinda funny that this was supposedly done in order to "reduce the uncertainty with which the meter may be realized." Is there "certainty" about what a "second" is?"
For that matter, is there any certainty about fast light will travel in a vacuum? Once again, the definition of a "meter" is now: The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second."
But I just quoted Einstein himself as sayin: "On the contrary, we arrived at the result that according to this latter theory the velocity of light must always depend on the co-ordinates when a gravitational field is present."
Where's the certainty about that definition then? The definition ignores the "co-ordinates when a gravitational field is present." Of course we all know exactly what a gravitational field is, and just how it operates, so that's no problem at all, but, still.....
Hmm, now what's a second again? Sumthin like "The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition..."
Over 9 billions "periods," eh? I wonder who's counting those periods, exactly? If you could count one a second....well, hold on, if you could only count 1 a second, then over 9 billion would have already occurred....let's start over...
If you could put those periods on a slow motion tape, and then count one a second, it would take...lemme see here....over 291 years, I figure, just to count the number of periods in one second. Whover counted them musta started sometime before 1720, even if he never slept a wink, it seems.
Mebbe someone came up with the number 9,192,631,770 by way of some fancy-ass mathematical calculation, but I doubt it. Formal systems like math are simply fictitious and can't be relied upon to tell you anything about reality.
If, during those 291 years of counting, the earth's rate of rotation became irregular, and if the guy stopped counting right then and there, and filmed a new atom to start countin, all over again, would he still count 9,192,631,770, I wonder? Or would be maybe count only 9,192,631,760 or sumthin?
So, now, we synchronize two celsium clocks. Then we put one in orbit. Let's say the one in orbit runs slower, and shows that only 59 seconds have passed in the same time the earth clock shows 60 seconds have passed.
Does that mean we would count 9,192,631,700 less "periods" for the orbiting clock? Or would they both continue to tick at the same rate and show an equal number of periods having passed, but just less time?
I will attempt to answer my own question here, because this seems, to me, to be the crux of the matter. According to Van Flandern:
"Cesium atomic clocks operate by counting hyperfine transitions of cesium atoms that occur roughly 10 billion times per second at a very stable frequency provided by nature. The precise number of such transitions was originally calibrated by astronomers, and is now adopted by international agreement as the definition of one atomic second.
GPS atomic clocks in orbit would run at rates quite different from ground clocks if allowed to do so, and this would complicate usage of the system. So the counter of hyperfine cesium transitions (or the corresponding phenomenon in the case of rubidium atomic clocks) is reset on the ground before launch so that, once in orbit, the clocks will tick off whole seconds at the same average rate as ground clocks. GPS clocks are therefore seen to run slow compared to ground clocks before launch, but run at the same rate as ground clocks after launch when at the correct orbital altitude."
http://www.metaresearch.org/cosmology/gps-relativity.asp
I will take Van Flandern's word for this at this point, but if you have information that he has mis-stated the situation, say so.
Let's start here and see what he is saying: "the counter...is reset on the ground before launch so that, once in orbit, the clocks will tick off whole seconds at the same average rate as ground clocks. GPS clocks are therefore seen to run slow compared to ground clocks before launch."
The counter of the clock intended for orbit is reset to tick off whole seconds at a rate which makes it "seen to run slow compared to ground clocks before launch," he says. Let's quanitify this.
Let's assume that, once in orbit, time will run at a rate which is only 90% of the earth clock. Instead of huge numbers, let's say the earth clock runs at a rate of 10 periods per second and 600 "periods" per minute. So what is done to the clock which will be put in orbit?
It is reset to make the clock tick off whole seconds tick off less frequency and therefore seems to run slower. In other words, it is adjusted to require 11.11 periods to record a second. It now records time at a slower rate than the earth clock, but it does NOT tick any slower. After 600 periods, the earth clock will show 1 minute as having elapsed, while in the same time the (to be) orbiting clock shows only 54 seconds passed (600/11.11). While both are on earth, each will have recorded 600 periods, it's just that one clock thinks it takes 11.11 periods to equal one second, and the other only 10. Sound right, so far?
OK, now what? Once in orbit, we have assumed the clock will run at a rate which is only 90% of the earth clock. So, if the earth clock "counts" 60 periods, the orbiting clock will record only 54 periods. But, because one has been calibrated differently in advance, both will agree on what one minute is:
earth clock: 10 periods = 1 second; 600 periods = 60 seconds
orbiting clock: 11.11 periods = 1 second =54 periods = 60 seconds (54 x 11.11 = 600).
Agree so far?
Assuming you do, what has happened here? The rate of "ticking" of the orbiting clock has slowed, that's what. On earth the orbiting clock counted 600 periods in one earth minute, but in orbit it counts only 54 periods in one earth minute.
So, contrary to your earlier claim, the orbiting clock does not run at the same rate that it did on earth. The rate has slowed down. "Time" has not slowed down, the ticking of the clock has. The slower ticking rate makes the counter "show" or "record" less time passing, but this is only because the ticking rate itself has actually slowed down.
Agree?
You asserted, without saying why, that my odometer analogies were "irrelevant," but they are not. They just illustrate the same principle as the clock situation as it pertains to distance. If I put on a tire with a diameter that is 11.11% bigger, then I need to adjust my odometer because what is was formerly calibrated to "assume" was one mile will now be wrong.
Once adjusted properly, it too will show that the distance to the post office is exactly 10 miles. That distance has not changed. The only thing that changed when I changed my tires was the proper calibration of my odometer.
Put another way, my odometer never did, and never will, measure distance, per se. It simply counts revolutions of my wheel, which it then translates into distance travelled.
Edit: In the post above, I said: "orbiting clock: 11.11 periods = 1 second =54 periods = 60 seconds (54 x 11.11 = 600)."
This was wrong, I got confused.
What I intended to convey was this: After having been re-calibrated, on earth it would take the (to be launched) clock 666.66 periods to record one full minute (11.11 x 60 = 666.66).
Once orbiting, and "ticking" at only 90% of it earth rate, it will record one full minute in only 60 periods. This is because it's rate of ticking has slowed from 666.66 per (earth) minute to 600 per (earth) minute, and therefore from 11.11 per second to 10 per second. So I should have said:
orbiting clock: 11.11/sec x .9 = 10 periods per second; 666.66/minute x .9 = 600 periods per minute, so 600 periods = 60 seconds.
The conclusion is the same, i.e., the ticking rate of the orbiting clock has slowed down and for that reason it agrees with the earth clock. Time (in some abstract sense) has not slowed down. The rate of the ticking has slowed down and, because it was set to run fast to begin with, the ticking rate of the orbiting clock now agrees with the ticking rate of the earth clock and hence their respective assumptions of how much time has elapsed (deduced from the periods counted) now agree.
As Van Flandern said: "GPS atomic clocks in orbit would run at rates quite different from ground clocks if allowed to do so..."
So, to take another perspective, we can ask what would happen if we did NOT pre-adjust the clock to be launched into orbit.
On earth, it was calling 600 periods one minute. In orbit, it will continue to call 600 periods one minute. But in orbit, it will run faster, because the "periods" it is counting will occur more frequently, i.e., it is ticking at a faster rate.
If it continues to call 600 periods "one minute," it will say a minute has passed after only 540 periods have passed. It will therefore equate 54 earth seconds to what is in fact one earth minute, i.e. it will run "faster."
In either case, the same phenomenon is responsible for the difference: the FREQUENCY with which the "periods" occur has changed. This is not "time itself." The clock still keeps time by merely "counting" periods, and it is the frequency of those periods which has changed.
In the odometer/distance analogy there is the same parallel. When I change my tires to a larger diameter size, the distance I go with each revolution of my wheel increases. My odometer continues to merely count the number of tire revolutions, not the "distance" itself, which has been pre-programmed into it. The pre-programming is now based on erroneous assumptions, but the distance itself has not changed.
Edit: Should have said: "If it continues to call 600 periods "one minute," it will say a minute has passed after only 540 periods have passed [ON EARTH]."
That is because, due to a slowing in frequency, 600 periods in orbit will occur in only 54 earth seconds instead of in 60 earth seconds.
Once again, the point is simply that clocks in motion to not simply continue to "run at the same rate" as they did when not moving. They run at a slower rate because the frequency of the occurences which they have been calibrated to measure has actually changed.
Because time is such an abstract, derivative (from motion and/or "change" in general), and slippery concept, I think the underlying point is more easily understood in terms of distance.
I can't see two different "points in time" at all, let alone see them both "at the same time." But I can see two points in space at the same time. Let those two "points" be the center of two telephone poles, 100 yards apart. I can see them both, and I can stretch a calibrated rope between them. If I calibrate one rope so that it calls 1.5 feet one yard, then it will measure 50 yards between them while a (properly calibrated) rope will say the distance between them is 100 yards.
Neither is moving with respect to the other (so the distance is not changing with time) and therefore "time" is not a factor in this measurement. However far apart I may measure them to be with ropes which are calibrated differently (i.e., whether 100 yards, 50 yards, 10 yards, or whatever) they remain the same distance apart. One should not confuse the readings given by instruments of measurement of distance with the actual distance itself.
I'm careless in my writing, and non-existent as an editor (pre-posting). I think you know what I meant, but I should have said:
"If I calibrate one rope so that it calls 1.5 feet one yard, then it will measure 200 [not "50"] yards between them while a (properly calibrated) rope will say the distance between them is 100 yards."
Trying to change this fact with counter-arguments based on tautology and definitions will be unsuccessful. I can, of course say, that if the calibrations on the rope call 30 feet one yard, and I therefore measure the distance between the poles to be 10 yards, then, for me, according to my own arbitrary definitions, the distance actually "is" only 10 yards. The same argument would apply if it measures 50 yards, 100 yards, 1000 yards, or whatever.
The problem with that argument is that, no matter how many different number of "yards" you assign to it, it is still the same distance. Only the names have changed, not the substance.
To carry this point to it's conclusion relative to SR, let's assume that someone stole my 100 yard rope and replaced it with a 10 yard rope. Let's assume that they also calibrated it on a 1/10 scale. It other words, my measuring instrument has "shrunk." Now I measure 1000 yards, not 100 yards, between the two poles if I use that rope to measure the distance.
How could it measure 100 yards yesterday, and 1000 yards today? Well, I guess there're only a few apparent explanations:
1. My "yardstick" has changed,
2. The distance between the poles has changed, or
3. Both have changed.
If I put faith in yardsticks, then I must say the distance has changed. If I put faith in the notion that telephone poles don't just magically move an additional 900 yards apart overnight with no apparent explanation, then I must say the yardstick has changed.
In the second case, I assume that the two poles are still only "really" 100 yards apart, notwithstanding the fact that I now measure them to be 1000 yards apart, because changing my yardstick does not change the distance.
Lets say I have a yardstick which I consider to be an "absolute" yard, and a clock which I consider to give a measure of "absolute" time.
Now say I have two telephone poles, one of which is 1 mile away, and one of which is two miles away (each measured by by absolute yardstick). Now say a beam of light is emitted from each pole at the exact same time (as measured by my absolute clock).
Now let's say both beams reach me at the exact same time. What am I to conclude? I can only conclude that the light beam from the pole 2 miles away travelled twice as fast. But why should one travel twice as fast? I dunno, but it does.
Why not just say that your so-called "absolute" yardstick and/or your so-called "absolute" clock changed for each measurement and that the speed of light remained the same for both? Why should light always travel at the same speed? I dunno, but I posit that it does.
That's fine, you go on ahead and posit that it does, I will continue to posit that it doesn't, how's that?
That's no good, because you have no way of proving that your yardstick and clock are absolute.
Oh, yeah? Well, you have no way of proving that the speed of light is constant, so there.
One Brow said: "if light is exceeds c on one direction, it must be slowed by a smaller amount in the opposite direction to make this average of c happen."
You say this as though it is inherently unreasonable, but why should it be? If I repeatedly throw a rubber ball against the same spot on a wall 100 feet away at the same speed (when it leaves my hand), it will always come back to me in the same amount of time. It's average speed will always be the same. But that hardly means it comes back to me at the same speed with which it left my hand, or that it travelled at the same rate of speed over every inch of it's journey, does it?
If I am moving 100 mph in the direction of the wall when I throw it, it will also have to travel farther to get to the wall that it does to get back to me, so it should take longer to hit the wall than it does to get back to me. If I insist that it has to do so with a constant speed, then I better start shortening my measuring rods and/or slowing my clock to make that happen, mathematically.
People get confused by averages sometimes. Try this one on someone you know sometime:
A car goes 2 miles. The first mile is uphill, the second mile is downhill. If it travels the first mile uphill at 30 mph, then how fast does it have to go downhill to average 60 mph over the whole 2-mile trip?
A common answer is: 120 mph, as is 90 mph
If I bounce a photon off a mirror and then it comes back to me, at what speed is it travelling when it hits the mirror and is about to reverse directions? It would seem to be zero, right? It has to at least temporarily stop before it can reverse directions, don't it?
One Brow said: "No, even if you assume Rob is moving and Bob is stationary, the answer is still that Bob will be younger. This comes from a "time slippage" in the not-conserving framework, remember?"
This isn't right.
Except it is. The answer remains the same no matter what your viewpoint, even the one where Bob never moves.
It is the "traveler's" clock which is adjusted.
As an effect of the gravitational fields the shipboard twin sees the planet-bound twin experiencing, in the point of view where the shipboard twin is stationary.
Read it closely (and the contrast between the geometry of SR and that of GR). I think you are confusing the geometry (euclidean) used by minkowski to create a model for SR with the riemannian geometery developed in connection with GR.
http://en.wikipedia.org/wiki/Minkowski_space
Neither of us was quite correct. Minkowski space is not Euclidean, but not curved in the manner I thought.
Using the notion of "distance" to "define" time just makes it all the more incomprehensible. Does "distance in time" just mean "duration," here, is that it?
That would be one way of interpreting it, just like "length" would be a distance that is purely space-like. In space-time, a distance can be length, duration, or a combination of the two.
Nobody I know defines a year in terms of distance (whether in time, or otherwise).
It is fairly standard relativistic thinking.
Time is a conceptual construct which we derive from the experience of motion.
Does that differentiate it from length?
Do you disagree with this statement?
No, but a discussion about the appropriate way to determine units of time is not directly relevant to time being a dimension.
So SR affect quantities of objects now, too?
Was the metaphor extension really that hard? The answer of whether Pat or Chris ages faster is observer-dependent.
One Brow said: "In SR (and GR, as I understand it), the question of whether Pat or Chris is "really" moving does not even make sense."
I thought we had explicity agreed otherwise in prior posts. The question "makes sense," it just can't be answered.
The question of which is aging faster makes sense, and the answer is observer-dependent. The quesiton of which is "really" moving does not make sense.
One Brow said: "GR is an extension of SR, there is nothing allowed in GR and forbidden to SR."
Really?
"Special relativity is founded) on the basis of the law of the constancy of the velocity of light. But the general theory of relativity cannot retain this law. On the contrary, we arrived at the result that according to this latter theory the velocity of light must always depend on the co-ordinates when a gravitational field is present." (Albert Einstein)
Really. Even in SR light moves slower throught a medium, such as air, water, glass, etc. GR adds "gravitational field" to that list.
GSR also allows for faster than light travel, eh?:
In that it allows for distortions in space-time that can make slower-than-light travel move from one locaiton to another in what appears to be faster-than-light to an observer well removed from the distortion. Is Star Trek they called it "warp drive" as opposed to Alcubierre drive.
I have no way to measure the size of the universe. Does that mean the universe "has no size?"
It means if you tell me the universe measures x one day, y the next day, and x again the day after that, I'm not going to take your claims very seriously. After all, I'm not claiming light has no one-way speed.
One Brow said: "if light is exceeds c on one direction, it must be slowed by a smaller amount in the opposite direction to make this average of c happen."
Exactly, in which case the speed of light would not be constant, which was the only issue in question.
You still need something to explain not only the differing speed, but the reason for unequally differing speed.
So, what has happened here? When it started out, speed was time divided by distance. In other words, you had to know the distance (and the time) in order to determine the speed.
Then Einstien simply "posited" that the speed of light is constant in a vacuum.
The second defined without reference to speed or lenght, and the two-way speed of light, the only type that can be independently measured, is c in SR, LR, and any other currently proposed system. YOu can use them to deine a meter, to the degree a vacuum can be produced.
Is there "certainty" about what a "second" is?
There is a certain definition.
Doesn't that measure of time itself constantly change with speed according to SR?
No, it doesn't.
Either way, they are defining a "second" as a "duration" also said to be a "unit of time." I don't see anything in there about dimensions or distances, for some reason.
Since you quoted it and then didn't see it, I can only assume your vision is at fault. After, a meter is a "length" and a "unit of space".
Does it concern you at all, Eric, that you scoff at Feser for thinking that euclidean geometry, (a "formal system") can tell you anthing about truth, but then proceed yourself to proclaim the "truth" about space, based upon the application of riemannian geometry?
Euclidean geometry is no longer predictive of the universe we see, Riemannian geometry is predictive. Since Dr. Feser is claiming not that Euclidean geometry is internally consistent, but that is it true in the same sense "water is H2O" is true, I have no compunction scoffing.
Where's the certainty about that definition then? The definition ignores the "co-ordinates when a gravitational field is present." Of course we all know exactly what a gravitational field is, and just how it operates, so that's no problem at all, but, still.....
If you mean that we will never be able to measure light in a true vacuum, I agree.
Mebbe someone came up with the number 9,192,631,770 by way of some fancy-ass mathematical calculation, but I doubt it. Formal systems like math are simply fictitious and can't be relied upon to tell you anything about reality.
I expect it was more like that cesium was chosen because the behavior in question seemed regular and easy to measure, and the number was chosed to conform with a traditional second.
So, now, we synchronize two celsium clocks. Then we put one in orbit. Let's say the one in orbit runs slower, and shows that only 59 seconds have passed in the same time the earth clock shows 60 seconds have passed.
Does that mean we would count 9,192,631,700 less "periods" for the orbiting clock?
Yes, if we remained on earth.
I will take Van Flandern's word for this at this point, but if you have information that he has mis-stated the situation, say so.
Wouldn't the GPS clocks need to run faster on earth to account for time dilation in orbit?
Assuming you do, what has happened here? The rate of "ticking" of the orbiting clock has slowed, that's what. On earth the orbiting clock counted 600 periods in one earth minute, but in orbit it counts only 54 periods in one earth minute.
So, contrary to your earlier claim, the orbiting clock does not run at the same rate that it did on earth. The rate has slowed down.
From our point of view, the clock has slowed down. From its own point of view, it has not. The reason for the difference is not due to the clock slowing, but due to it's traveling less in the time dimension. As long as you think the phenomenon is that something is slowing, this will be a struggle for you.
Put another way, my odometer never did, and never will, measure distance, per se. It simply counts revolutions of my wheel, which it then translates into distance travelled.
I agree. The odometer is not measuring distance directly. The odometer is translating wheel rotations based on the assumed circumference of the wheel. However, clocks measure distance directly. If you don't think that, then answer what you think the equivalent of the metaphorical assumed circumference and wheel rotation count is when discussing time dilation.
I can't see two different "points in time" at all,
You do this continually. You look at the screen at two different moments, you will see the screen at two different points in time.
let alone see them both "at the same time."
This is like saying you can't see two different locations in space at the same location.
But I can see two points in space at the same time.
You can also see the same point in space at different times.
Lets say I have a yardstick which I consider to be an "absolute" yard, and a clock which I consider to give a measure of "absolute" time.
Now say I have two telephone poles, one of which is 1 mile away, and one of which is two miles away (each measured by by absolute yardstick). Now say a beam of light is emitted from each pole at the exact same time (as measured by my absolute clock).
Where is the absolute clock located inorder to see the emissions as simultaneous?
You say this as though it is inherently unreasonable, but why should it be? If I repeatedly throw a rubber ball against the same spot on a wall 100 feet away at the same speed (when it leaves my hand), it will always come back to me in the same amount of time. It's average speed will always be the same. But that hardly means it comes back to me at the same speed with which it left my hand, or that it travelled at the same rate of speed over every inch of it's journey, does it?
Of course, according to VFLR, you can throw the ball as fast as you want, but the faster you throw it, the slower it goes on the return journey.
People get confused by averages sometimes. Try this one on someone you know sometime:
A car goes 2 miles. The first mile is uphill, the second mile is downhill. If it travels the first mile uphill at 30 mph, then how fast does it have to go downhill to average 60 mph over the whole 2-mile trip?
A common answer is: 120 mph, as is 90 mph
No doubt, when the real answer is that it can't be done, of course.
If I bounce a photon off a mirror and then it comes back to me, at what speed is it travelling when it hits the mirror and is about to reverse directions? It would seem to be zero, right? It has to at least temporarily stop before it can reverse directions, don't it?
My understanding is that is shows a wave-like behavior if it bounces, and requires no period of acceeration.
Eric, which of these two ontological views would you say is right, or more right?
1. What I call something is what it is, and, conversely, what something is is what I call it, or
2. What something is does not depend on what I call it, and, conversely, what I call something does not make it what it is.
I said: This isn't right.
You responded: "Except it is. The answer remains the same no matter what your viewpoint, even the one where Bob never moves."
Eric, you need to really think this through rather than simply reassert your conclusion. Your answers are becoming more and more inconsistent with each other.
You are now saying, in effect, that if two people are moving relative to each other, then one will always be younger than the other, and that "one" will always be the same one, regardless of who is actually moving. This not only contradicts your own prior statements, but it also contradicts all the logic and premises set forth in the wiki explanation.
I said: Either way, they are defining a "second" as a "duration" also said to be a "unit of time." I don't see anything in there about dimensions or distances, for some reason.
You responded: Since you quoted it and then didn't see it, I can only assume your vision is at fault. After, a meter is a "length" and a "unit of space".
*My* vision is at fault, eh? Can you show me where the word "meter" is used in connection with the definition of a "second?"
http://physics.nist.gov/cuu/Units/second.html
Click on the "meter" tab at the top to get the definition of a meter.
"Special relativity is founded) on the basis of the law of the constancy of the velocity of light. But the general theory of relativity cannot retain this law." (Einstien)
I quoted this in response to your claim that GR does nothing that is prohibited by SR.
Einstein says the "law" about the constancy of light must be broken in GR. Then you come back with this:
One Brow said: "Really. Even in SR light moves slower throught a medium, such as air, water, glass, etc. GR adds "gravitational field" to that list."
Are you really trying to imply that Einstein himself had no clue about light changing in different media when he formulated the "law of the constancy of the velocity of light" which is the "basis" which special relativity is "founded on?"
The qualification "in a vacuum" was of course implied in his statement, so your profound insight into change of lightspeed with media is simply irrelevant.
The point Einstein made remains: SR prohibited the speed of light to vary in a vacuum. This prohibition must be broken in GR.
This is simply one more reason why the claim that SR "led to" GR is erroneous. Einstien struggled for years trying to make GR consistent with SR in this respect, but could not. He had to abandon SR to formulate GR. If anything, SR led him "away" from GR, not "to" it.
I said: "I can't see two different "points in time" at all..."
You responded: "You do this continually. You look at the screen at two different moments, you will see the screen at two different points in time."
No, I am seeing computer screens. The concept of time is derivative from that. I can't see "time."
You quoted me: "I will take Van Flandern's word for this at this point, but if you have information that he has mis-stated the situation, say so."
You asked: "Wouldn't the GPS clocks need to run faster on earth to account for time dilation in orbit?"
This all gets confusing with different time frames, I know. Van Flandern says: "GPS clocks are therefore seen to run slow compared to ground clocks before launch."
Once it is adjusted (assuming a 10% change once in orbit), the clock calls only 54 seconds "one minute." It is therefore running slower than the earth clock which call one minute one minute.
I said: "This all gets confusing with different time frames, I know. Van Flandern says: "GPS clocks are therefore seen to run slow compared to ground clocks before launch."
Once it is adjusted (assuming a 10% change once in orbit), the clock calls only 54 seconds "one minute." It is therefore running slower than the earth clock which call one minute one minute."
I can see where this doesn't sound right. It's all a matter of the perspective taken when interpreting the word "slow," I guess.
If the earth clock says an hour has passed, and the other clock says says 66.66 minutes have passed, then the adjusted clock is running "faster" in that sense.
From another perspective, the adjusted clock runs "slower" because it takes 11.11 periods to count a second whereas only 10 periods count as a second for the earth clock.
Let me think about it some more....
One Brow said: "However, clocks measure distance directly. If you don't think that, then answer what you think the equivalent of the metaphorical assumed circumference and wheel rotation count is when discussing time dilation."
OK. First of all, clocks don't measure "distance directly," so I'm assuming you mean they measure "time directly."
Clocks don't measure time directly either. Like the odometer, clocks merely count the number of recurring physical phenomena which they are calibrated to. In a cesium clock, they count the "periods" (fill in the rest of the definition for yourself).
The analogy would be this: Suppose I line up one million clocks, each calibrated to call a different number of periods one second. For example, one clock might be calibrated to call 9,555,555,555 periods "one second," the next might be calibrated to call 9,555,555,554 periods "one second," etc.
Now then, I have have them all calculate a "time" for a single event (say the time it takes me to get out of my chair once the doorbell rings). They then give me a million different answers to the question of "how long (how many seconds) did that take?"
If you want to take an operational definition as being the "true" one (i.e., if you want to put your faith in clocks), then the event did in fact take a million different durations to occur.
But, no matter how many clocks you have, or how many different readings you get from them, it is still only one event. It is a mistake to say that each of them is right, and/or that the event took one million different amounts of time to complete simply because there are a million clocks with different readings to somehow explain.
The clocks, like the odometer, "translate" a particular count of a particular phenomena (revolutions of a wheel, and cesium "periods," respectively) into a presumed "passage of time."
I said: "Let me think about it some more...."
OK, let me see if I can keep from confusing myself this time.
Assuming that, for the earth clock, 600 periods is called "one minute," then we will want the orbiting clock, once in orbit, to also call 600 periods "one minute." Then they will be synchronized from that point forward.
Assuming that the orbiting clock will "slow down" by 10% once it is in orbit, what do we have to do to it now? We have to have it call 540 periods "one minute" now, while on earth, right? In other words it will say 1 minute has passed after counting only 540 periods (which are actually occuring at the rate of 600 per minute of earth time). On the other hand, after it has actually counted 600 periods, it will say 66.66 seconds have passed.
So, like I said, it seems to be a matter of perspective as to whether is running "fast" or "slow" when compared to the non-adjusted earth clock.
In the sense that the instrument it is based on reads out more minutes in less time, the adjusted clock is running faster.
But from another perspective, since the earth clock requires 600 periods to read one minute while the adjusted clock only requires 540 periods to read one minute, the adjusted clock is "slower." 540 periods is less than 600 periods. So in that sense the earth clock is "faster," i.e., it records 600 periods in what it calls one minute, while the adjusted clock counts only 540 periods in what it call one minute. Since the earth clock has more periods per minute, it is "ticking faster."
Does that make sense (bona fide question, I'm not entirely sure it does, except from a certain perspective)?
I don't think it really matters, in terms of the princples behind the synchronization, which one you wish to call "faster."
One Brow said: "then answer what you think the equivalent of the metaphorical assumed circumference and wheel rotation count is when discussing time dilation."
The analogy is not as direct, but let's look at this in the context of the GPS clock and the Earth clock. After adjustment, and after being put into orbit, the GPS will call 600 periods one minute, even though one was running faster pre-launch. The earth clock will also call 600 periods one minute. So what does this "really mean?"
If we want to go by definitions, and if the international standard for a "true" minute is 600 periods, then each clock is giving you a "true minute."
If that is the case, then how could you possibly say that one is faster or slower than the other? In the definitional sense they are NOT running at different rates, and gravitation is not affecting either clock differently at all.
How would you disentangle this puzzle? For me, it would be answered in terms of the way time is defined and the way clocks are calibrated, which is not "time itself." Clocks, in my view, don't measure "time itself." The measure only what they are required to "count" and translate that into a "time duration" strictly in accordance with the way they are calibrated, not as dictated by "time itself."
One Brow said: "So, contrary to your earlier claim, the orbiting clock does not run at the same rate that it did on earth."
Where did I claim that "the orbiting clock run[s] at the same rate that it did on earth." I took this to be YOUR claim, not mine.
Of course the same clock changes it's rate of ticking when it is moving at a higher speed (or less gravity) than it formerly did, this is precisely what SR presumes, as does SR (except SR says only time is changing, which is simply a different way of looking at it).
In the examples we have been using, on earth an adjusted clock calls 600 periods 66.66 seconds Once in orbit it will call those same 600 periods one minute (60 seconds). It does not continue to call the same number of periods the same time duration because it's rate of ticking has slowed down.
In terms of cesium periods, the frequency with which the periods occur slows down. Whereas on earth 600 periods will occur in 60 seconds in orbit 600 periods will require 66.66 earth seconds to occur. The periods don't occur as frequently once in orbit.
Substituting "human heartbeats" for "cesium periods" the heartbeat would slow down in orbit. If 60 heartbeats occured in 60 seconds on earth, those same 60 heartbeats would require 66.66 earth-seconds to occur in orbit. The heartbeat has "slowed down."
One Brow said: "then answer what you think the equivalent of the metaphorical assumed circumference and wheel rotation count is when discussing time dilation."
One more way of looking at it:
My odometer is calibrated to call 660 revolutions 1 mile, because it assumes that every revolution moves me 1/660th of a mile (8 feet). Now, suppose I increase the circumference of my tire to 9 feet. Now I will go a mile in only about 587 revolution instead of 660.
It will now require more energy to move my car one revolution than it did before, so I won't save on gas, but it will still be 10 miles to the post office.
If I recalibrate my odometer to call 587 revolutions 1 mile, then it will tell me that it is still 10 miles to the post office with my new tires. If I don't, it will tell me it is only about 8.9 miles to the post office.
Let's assume that, regardless of what any particular odometer says, it is actually 10 miles to the post office, OK?
The point here is this: Having changed the circumference of my tire, it actually does take less revolutions of my wheel to get me to the post office. The odometer is simply calculating a revolution to distance ratio, whether based upon erroneous assumptions or not.
Likewise with clocks. If the frequency of an event upon which I am premising a clock does actually slow down or speed up, the reading which it gave me under different circumstances will change. The same odometer which told me it was 10 miles to the post office one day told me it was only 8.9 miles the next, but NOT because the distance changed.
Same deal with a clock put on a plane. If the frequency of the event the clock is designed to count (analogous to the counting of wheel revolutions which the odometer does) changes, then the clock will tell me that more (or less) time has passed than it did before. This is analogous to the change in tire circumference in the odometer example, which actually did change the distance travelled with each revolution.
The speedometer in my car works on the same principles as the odometer, of course. The difference is that it counts the frequency of revolutions, not the absolute number, and it translate that frequency into mph, not distance.
If my speedometer assumes that I move 8 feet with each revolution, and it counting the frequency of revolutions per minute to be 500, then it will tell me that I am moving at the rate of 4000 feet per minute (about 45 miles per hour). If I change my tires, it will STILL tell me I am going 45 miles per hour when I am racking up 500 rpm unless I recalibrate it. But in actuality I will be travelling 4500 feet per minute (500 x 9) or about 51 mph. Unless I re-calibrate it, I might git me a speedin ticket goin 51 in a 45 zone, ya know?
The point is the same. The "speedometer" is not calculating "true speed." One must know the distance, as well as the time, to calculate speed, and it is no more measuring distance than my odometer was. It is simply mechanically giving me a mph figure based upon certain assumptions regarding the frequency of wheel revolutions and the circumference of my tires.
One Brow said: "Minkowski space is not Euclidean"
Well, no not strictly, and I never claimed that is was, strictly speaking. I was simply referring to straight lines and flat space.
The only reason it is not euclidean, best I can tell, is because Minkowski added in a 4th dimension that Euclid never even thought about. Euclid's geometry has only 3 spatial dimensions--which Minkowski relied upon. Part of his proof depended on the dreaded, and woefully incorrect, pythagorean theorem as I understand it. From wiki:
"In theoretical physics, Minkowski space is often contrasted with Euclidean space. While a Euclidean space has only spacelike dimensions, a Minkowski space also has one timelike dimension....Strictly speaking, the use of the Minkowski space to describe physical systems over finite distances applies only in the Newtonian limit of systems without significant gravitation. In the case of significant gravitation, spacetime becomes curved and one must abandon special relativity in favor of the full theory of general relativity....In the realm of weak gravity, spacetime becomes flat and looks globally, not just locally, like Minkowski space. For this reason Minkowski space is often referred to as flat spacetime."
The middle part of that quote reinforces a point I made earlier, i.e., that "...one must abandon special relativity in favor of the full theory of general relativity."
One Brow said: "Of course, according to VFLR, you can throw the ball as fast as you want, but the faster you throw it, the slower it goes on the return journey."
No, I disagree, even though I'm not sure what VFLR is supposed to stand for.
Let's take a typical example where LR might differ from SR. Let's say I am moving apart from planet B at a rate which is .5c. Assume that planet B is currently one lightyear away from me. Now let's assume that I am stationary. That would mean that planet B is moving away from me at the rate of .5c. Now I "throw a ball" at it at the speed of light.
Because it is moving away from me, it will approach (gain on) planet B at the rate of .5c. Without bothering with the math, it is easy to see that it's gunna take a good long while for the ball to catch up with planet B. Partly because it is already a good distance away, but even moreso because as the ball tries to catch up with it it keeps moving away.
One the ball hits it, and starts to return, it now has a definite, unchanging distance to travel back to me (remember, I have remained motionless all this time). Now the absolute distance required to reach me will NOT change with time was the case when the ball was trying to catch up with planet B. For that reason it will take less time to return to me than it did to reach planet B in the first place. Assuming that it was at all times travelling at the absolute speed of c, and continues to do so, it will return to me at the rate of c. Assuming that the ball continues to travel at c (relative to me), it does not go "slower" on the return trip, it approaches me at c, the same speed at which I threw it. It does, however, take more time to hit planet B than it does to return.
It's not that the ball is not travelling at a constant speed (c) with respect to me that varies, it's that it will not be seen that way from all inertial frames. Planet B will see it as approaching at .5c, and as receding at 1.5c, or whatever (I don't feel like messin with the math here--just call me one of those who would say the car has to go downhill at the rate of 90 mph to average 60 mph).
Sumthin like that, I think.
One Brow said: "From our point of view, the clock has slowed down. From its own point of view, it has not. The reason for the difference is not due to the clock slowing, but due to it's traveling less in the time dimension. As long as you think the phenomenon is that something is slowing, this will be a struggle for you."
I see now that I made a mistake earlier. I thought I was quoting you, when in fact I was just quoting you quoting me. Sorry, eh?
That apology having been made, you are first saying: "The reason for the difference is not due to the clock slowing, but due to it's traveling less in the time dimension."
It's this "travelling less in the time dimension" business which is simply fictitious, as I see it. I know that you were thinking (and perhaps still are) that a "second" (a unit of time) has been defined in terms of a "meter" (a unit of distance), but that's not the case. As I said originally, the definition of a "second" makes no reference whatsover to a "meter" or to "travelling." Nor does it refer to a "time dimension," whatever that is. So "travel in a time dimension" has nothing to do with the way I understand time as a practical (as opposed to geometrical) matter.
Then you say: "As long as you think the phenomenon is that something is slowing, this will be a struggle for you."
Yes, I agree, it will be. Don't get me wrong, I understand (more or less) what you are referring to in terms of a formal mathematical model, i.e., the new "dimension" added by Minkowski. It's just that, like you used to purport to believe, I don't take purely mathematical models as necessarily being "true" or having some exact correspondence to "reality."
Calling time a "dimension" for mathematical/geometrical purposes is OK, but it makes no sense to me a as "real world" concept or application. If it does to you, you may have a lot more in common with Feser than you think.
Eric, which of these two ontological views would you say is right, or more right?
1. What I call something is what it is, and, conversely, what something is is what I call it, or
2. What something is does not depend on what I call it, and, conversely, what I call something does not make it what it is.
I lean more toward the second, in matters of objectivity, and the first in matters of subjectivity/purpose. If I use a certain piece of metal to pounds nails and I call it a hammer, then its a hammer even if you might think it is scrap, or a wrench.
Eric, you need to really think this through rather than simply reassert your conclusion. Your answers are becoming more and more inconsistent with each other.
I have thought this through. More to the point, this is also how the wikipedia article presents it. Regardless of whether you interpret events to say that Bob is stationary or that Rob is stationary, Rob will age more.
You are now saying, in effect, that if two people are moving relative to each other, then one will always be younger than the other, and that "one" will always be the same one, regardless of who is actually moving.
I think you are confusing Pat and Chris with Bob and Rob, or at least my statements concerning Pat and Chris with those concerning Bob and Rob.
*My* vision is at fault, eh? Can you show me where the word "meter" is used in connection with the definition of a "second?"
That was offered as an analogy. A duration is a distance in space-time that occurs only in the time-like dimension.
Are you really trying to imply that Einstein himself had no clue about light changing in different media when he formulated the "law of the constancy of the velocity of light" which is the "basis" which special relativity is "founded on?"
Einstein formulated light was constant in a vacuum. He later had to correct this to say in a vacuum without gravity. Of course he knew about light chnging veliocity in some circumstances, he just added an additional circumstance with GR.
The point Einstein made remains: SR prohibited the speed of light to vary in a vacuum. This prohibition must be broken in GR.
The speed of light is only c until it isn't, remember?
This is simply one more reason why the claim that SR "led to" GR is erroneous. Einstien struggled for years trying to make GR consistent with SR in this respect, but could not. He had to abandon SR to formulate GR. If anything, SR led him "away" from GR, not "to" it.
GR did not abdon SR, it incorporated it with a small in what could affect the speed of light.
No, I am seeing computer screens. The concept of time is derivative from that. I can't see "time."
Of course you can't see time, any more than you can see length. However, when you lood at the screen after a small duration, you see the screen at different points in time, just like you can see the ends of a rope in different places.
I can see where this doesn't sound right. It's all a matter of the perspective taken when interpreting the word "slow," I guess.
Probably. I think your explanations are correct.
OK. First of all, clocks don't measure "distance directly," so I'm assuming you mean they measure "time directly."
Distnance in the time dimension.
Clocks don't measure time directly either. Like the odometer, clocks merely count the number of recurring physical phenomena which they are calibrated to. In a cesium clock, they count the "periods" (fill in the rest of the definition for yourself).
That's like saying a ruler doesn't measure directly, it counts the number of hashmarks between two points. I'm perfectly comfortable with this notion that length and time can not be measured directly. I only object to a claim one can be and other can not.
Now then, I have have them all calculate a "time" for a single event (say the time it takes me to get out of my chair once the doorbell rings). They then give me a million different answers to the question of "how long (how many seconds) did that take?"
If you measure a length in centimeters and in inches, you'll get two different numbers as well. That you can change the units being measured does not mean you can't measure something (although, again, I'm prefectly willing to accept a claim you can't measure length or duration directly, if that is your claim).
But, no matter how many clocks you have, or how many different readings you get from them, it is still only one event. It is a mistake to say that each of them is right, and/or that the event took one million different amounts of time to complete simply because there are a million clocks with different readings to somehow explain.
OK.
Likewise with clocks. If the frequency of an event upon which I am premising a clock does actually slow down or speed up, the reading which it gave me under different circumstances will change. The same odometer which told me it was 10 miles to the post office one day told me it was only 8.9 miles the next, but NOT because the distance changed.
Under GR/SR, the frequency of the clock does not change locally. It only changes in comparison to some non-local clock. The earth-bound obserbver see what he interprets as a slower clock, because the clock is moving less in the time dimension (again, this is the geometric interpretation of GR).
One Brow said: "Of course, according to VFLR, you can throw the ball as fast as you want, but the faster you throw it, the slower it goes on the return journey."
No, I disagree, even though I'm not sure what VFLR is supposed to stand for.
Van Flandern's version of Lorentzen relativity.
Let's take a typical example where LR might differ from SR. Let's say I am moving apart from planet B at a rate which is .5c. Assume that planet B is currently one lightyear away from me. Now let's assume that I am stationary. That would mean that planet B is moving away from me at the rate of .5c. Now I "throw a ball" at it at the speed of light.
Because it is moving away from me, it will approach (gain on) planet B at the rate of .5c. Without bothering with the math, it is easy to see that it's gunna take a good long while for the ball to catch up with planet B. Partly because it is already a good distance away, but even moreso because as the ball tries to catch up with it it keeps moving away.
One the ball hits it, and starts to return, it now has a definite, unchanging distance to travel back to me (remember, I have remained motionless all this time). Now the absolute distance required to reach me will NOT change with time was the case when the ball was trying to catch up with planet B. For that reason it will take less time to return to me than it did to reach planet B in the first place. Assuming that it was at all times travelling at the absolute speed of c, and continues to do so, it will return to me at the rate of c. Assuming that the ball continues to travel at c (relative to me), it does not go "slower" on the return trip, it approaches me at c, the same speed at which I threw it. It does, however, take more time to hit planet B than it does to return.
The ball travels the exact same distance to reach the planet as it does on the return trip. If you are 1 light-day from the planet when you throw the ball, it will hit the planet in two days, and take two days to make the return journey.
It's not that the ball is not travelling at a constant speed (c) with respect to me that varies, it's that it will not be seen that way from all inertial frames. Planet B will see it as approaching at .5c, and as receding at 1.5c, or whatever (I don't feel like messin with the math here--just call me one of those who would say the car has to go downhill at the rate of 90 mph to average 60 mph).
Even under LR, I'm don't think this is correct. This idea seems to run counter to the Lorentz transformations that LR accepts.
It's this "travelling less in the time dimension" business which is simply fictitious, as I see it. I know that you were thinking (and perhaps still are) that a "second" (a unit of time) has been defined in terms of a "meter" (a unit of distance), but that's not the case.
No, I don't think that.
So "travel in a time dimension" has nothing to do with the way I understand time as a practical (as opposed to geometrical) matter.
Whether you accept LR or SR/GR, the way we understand time as a practical matter changes.
It's just that, like you used to purport to believe, I don't take purely mathematical models as necessarily being "true" or having some exact correspondence to "reality."
That the model exists does not mean it correctly portrays reality. That no better model exists means we have little foundation to question the correspondence right now, but we should always keep an eye out for evidence that doesn't fit or an even better model, certainly.
This goes all the way to the managers's decision: on the basis of the evidence, even if you don't understand the reasons, do yo uhave a good reason to change your preference of which hitter to use? I don't think either of us is going to alter our decision.
Calling time a "dimension" for mathematical/geometrical purposes is OK, but it makes no sense to me a as "real world" concept or application. If it does to you, you may have a lot more in common with Feser than you think.
Perhaps so. I'm sure I do have more in common with Dr. Feser than I realize.
I said: "The speedometer in my car works on the same principles as the odometer, of course. The difference is that it counts the frequency of revolutions, not the absolute number, and it translate that frequency into mph, not distance...One must know the distance, as well as the time, to calculate speed, and it is no more measuring distance than my odometer was."
Needless to say, the exact same error could occur with respect to my speedometer even if I didn't change my tires, but if the clock the speedometer was relying on started running slow. If 67.5 seconds were actually passing in the time the speedometer caculated to be one minute, the distortion would be the same.
If I am going 8 feet with every revolution, then I will go 4000 feet at 500 rpm in a true minute about 45 mph). But I will travel 4500 feet (about 51 mph) in 67.5 seconds. Whatever the speedometer tells me, I am still travelling 4000 feet in sixty seconds; that hasn't changed. The clock simply needs to be recalibrated.
If my speedometer is off, it could be (1) because the assumption pertaining to distance travelled is mistaken, (2) because the assumption about minutes elapsed is mistaken, or (3) some combination of both, to a greater or lesser respective degree.
One primary point here is that any instrument which is designed to count and measure something which it will "translate" into the measurement desired (whether it be time, distance, or anything else), will be based on certain assumption. Once programmed with it's assumptions, it will simply continue to apply them, in a mechanical, non-cognitive fashion. It does not re-adjust itself because it somehow knows that .89 mile is not a "real" mile or that 67.5 seconds is not a "real" minute.
It will tell you that sumthin which aint a mile is a mile without compunction, remorse, or conscience. I don't trust them lyin bastards, my own damn self, ya know?
One Brow said: "The ball travels the exact same distance to reach the planet as it does on the return trip. If you are 1 light-day from the planet when you throw the ball, it will hit the planet in two days, and take two days to make the return journey."
Yes, I agree with you here. It should take the same time from my perspective, and I misstated that. The contrast with SR really comes with regard to the question of how fast the ball is travelling with respect to planet B, not me, the stationary observer.
One Brow said: "Even under LR, I'm don't think this is correct. This idea seems to run counter to the Lorentz transformations that LR accepts."
I think LR agrees with SR about what observers will measure, and is identical in that sense, so I wasn't careful enough in expressing the difference. LR simply takes the view that, regardless of how observers measure the same distance, it is still the same "real" distance. So, if they get different measurements, one, or both, of them is simply wrong.
One Brow said: "More to the point, this is also how the wikipedia article presents it. Regardless of whether you interpret events to say that Bob is stationary or that Rob is stationary, Rob will age more."
Well, if you ever change your mind about this, let me know. I don't see how you can possibly reach that conclusion, but you are doing it *somehow* I spoze. I will repeat myself (and wiki) one more time in an attempt to get you to re-evaluate your conclusions, then let it go:
"The issue in the general relativity solution is how the traveling twin perceives the situation during the acceleration for the turn-around."
They are not talking about either Bob or Rob, per se, here, they are talking about the "travelling twin" (which would be the earth twin if the rocket remained motionless on "blast-off" and simply pushed the earth away from it). And the whole explanation depends on who does the "turn-around," which would also reverse itself it the earth went away, then returned. Whoever is "travelling" and "turning-around" will be younger. It is not the circumstance of sitting in a spaceship instead of sitting on earth which determines this.
One Brow said: "This goes all the way to the managers's decision: on the basis of the evidence, even if you don't understand the reasons, do yo uhave a good reason to change your preference of which hitter to use? I don't think either of us is going to alter our decision."
Well, yeah, and of course "good reasons" depend on one's evaluations, which can be a very subjective thing.
I can easily understand why two clocks give two difference measurements of time if they are running at different rates. I may be utterly bewildered as to the reasons "why" they are running at different rates, but I can easily understand that maybe they are, and can easily see how that would explain the different readings they are giving me.
On the other hand, to say that two different clocks which are giving me different readings of time are running at the exact same rate and are only giving me different readings because "time itself" has changed is incomprehensible. Clocks are designed to measure time, whether they do so accurately or not. Time is not designed to "measure" clocks. To claim that "time itself" reaches out and calibrates the clocks to give the mechanical readings they give is just incomprehensible to me. "Time" is merely a notion, not a physical thing, as I see it, and I really can't see it as otherwise in a manner that makes practical (as opposed to theoretical) sense.
I have the same problem with Plato's "realm of forms," but many others see the claim of the "real" existence of such a realm as not only perfectly plausible, but as "necessarily true." It could be no other way, from their perspective. Each to his own, I guess.
Clocks are designed to measure time, whether they do so accurately or not. Time is not designed to "measure" clocks. To claim that "time itself" reaches out and calibrates the clocks to give the mechanical readings they give is just incomprehensible to me. "Time" is merely a notion, not a physical thing, as I see it, and I really can't see it as otherwise in a manner that makes practical (as opposed to theoretical) sense.
At no point have I tried to claim that time is reaching out to do anything. Let's try a simple, space-only illustration. I want to move from one corner of a square with sides of one mile to the opposite corner. If I move along the sides, I travel 2 miles. If I move along the diagonal, I travle less than .72 miles. This does not mean length has reached up adn affected my odometer, I just took a different path.
Bob (on the ship) takes a different path in spacetime than Rob (on the planet). Since spacetime is not flat, it is possible, by moving more in a spacelike fashion, to move less in a timelike fashion and arrive in the same space-time coordinates.
Whoever is "travelling" and "turning-around" will be younger. It is not the circumstance of sitting in a spaceship instead of sitting on earth which determines this.
I agree, and I don't think you can analyze the position of Bob being stationary in SR, because it has machinery to discuss what happens to Rob in this viewpoint. However, you can discuss this in GR. If you take the position of Bob being stationary in GR, then Bob's propulsion system actually activates tremendous gravitational fields that affect Rob and the rest of the universe. These fields cause, from Bob's point of view, time contraction for Rob, so that Rob still ages more than Bob. At least, that is how I interpreted the wiki article.
One Brow said: "when you lood at the screen after a small duration, you see the screen at different points in time, just like you can see the ends of a rope in different places."
No, it's not "just like" seeing two objects at once. You're leaving out an essential element here, viz., "change" (or differentiation in some sense, as when I look at two different objects simultaneously). I can look at the same screen continously for, say, one second, but if I have no sense of change during that second, I have no sense of time passing. I "see" changes, not time.
Theoretically, you could say that in that one second, I have seen 1,000,000 screens at "different" times (a different one each millionth of a second). Or one billion, one trillion, or whatever (again, all in theory). But I do not see, or in any other manner sense, the appearance and then disappearance of one trillion screens. For me nothing has changed if I don't move my head, hear a sound, think a thought, or experience some other thing that has changed in that one second duration.
I deduce a change in time, based upon my perception of change. I have no problem saying that time passes, whether I sense it, or not. Neither does LR. But if I sleep for 8 hours, I have no independent notion that 8 hours have passed. I can deduce that from looking at the sun, a clock, or some other thing that has changed since I last saw it, but it is strictly a deduction, not a perception or an observation of "time."
I said: "But if I sleep for 8 hours, I have no independent notion that 8 hours have passed."
I could, of course, say, and even understand in a metaphorical or theoretical sense, that time has stopped while I was asleep. But that would make no practical sense.
One Brow said: "If I move along the sides, I travel 2 miles. If I move along the diagonal, I travle less than .72 miles. This does not mean length has reached up adn affected my odometer, I just took a different path.
Bob (on the ship) takes a different path in spacetime than Rob (on the planet). Since spacetime is not flat, it is possible, by moving more in a spacelike fashion, to move less in a timelike fashion and arrive in the same space-time coordinates."
Heh, Eric, do you realize how obscure and abstract that second paragraph sounds? I swear that theoretical physicists are the modern-day metaphysicians. Their abstractions and mathematical proofs become "reality" for them and for the entire objective world, to hear them tell it.
Dark matter, 11 dimensions in string theory, gravitrons, what have you---if they can imagine it, they have no problem relying on it as a proper explanation. These are all deductions, some extremely tenuous, but they seem to think that their thoughts must dictate how reality is, at least if their thoughts are logically and mathematically consistent.
One Brow said: "At no point have I tried to claim that time is reaching out to do anything."
Not in so many words, no, but what else can you be implying? A cesium clock counts periods. 600 periods is 600 periods, and 9,832,357, 124 is that amount. It will count 600 when it counts 600, however far apart those periods may occur. If the frequency of those periods change, then the readings of the clock as far as time elapsed will change. Fine, I can understand that.
As one scientist I quoted said, the relativistic interpretation prohibits any such explanation (it would be duplicate of the built in assumptions, which are that time itself and distance itself changes). Since the speed of light has been posited to be constant, and since all inertial frameworks must have the same laws of physics, now one or both of the elements of speed (time and distance) must THEMSELVES change (and not just "appear" to change).
Ultimately this means that mechanically-based clocks always give the correct time and they somehow change their mechanical operations to conform to a "true" minute as such is determined by the particular time-frame they are in. All sounds kinda "spooky" ta me.
I have no problem with this claim:
1 hour = 60 minutes = 60 seconds = a unit of time
And, treated in a purely mathematical sense, the equal signs means that time "is" a second and that a second "is" time.
From there you can just as easily say that time makes a minute what it is and you can say that a minute makes time what it is. The two are, mathematically-speaking, mere equivalents.
Similarly you can say that 2 + 5 = 7, but they are equvialent only in an abstract sense. Furthermore 5 + 2 = 7, and there is no mathematical difference between the two statements.
But if the 7 represents my total bank accounts, the first number is the number of account in which I am overdrawn, and the second number represents the number of accounts which have in excess of $1,000,000, then 5 + 2 is clearly NOT equivalent to 2 + 5.
Meant to say this, of course:
1 hour = sixty minutes; 1 minute = 60 seconds; 1 second = a unit of time
LR: I now measure time and distance to be different because my instruments of measurement have changed. This explains why time and distance "appear" to change.
SR: I now measure time and distance to be different because time and distance have themselves changed. My instruments of measurement have not changed in the least, they take different measurements because the things they are measuring have actually, and not just apparently, changed, that's all.
Which one makes more sense? Well, it depends on what you put faith in, I guess. As I said before:
"How could it measure 100 yards yesterday, and 1000 yards today? Well, I guess there're only a few apparent explanations:
1. My "yardstick" has changed,
2. The distance between the poles has changed, or
3. Both have changed.
If I put faith in yardsticks, then I must say the distance has changed. If I put faith in the notion that telephone poles don't just magically move an additional 900 yards apart overnight with no apparent explanation, then I must say the yardstick has changed."
I can look at the same screen continously for, say, one second, but if I have no sense of change during that second, I have no sense of time passing. I "see" changes, not time.
So, time passes, but due to you limitations as a biological organism, you don't always see it? Why is this relevant to time actually passing and your observing two different positions in time, whether you are aware of it or not?
Heh, Eric, do you realize how obscure and abstract that second paragraph sounds?
Probably not to the same degree you do. I did train as a theoretical mathematician, so the abstract and obscure became my everyday vernacular. Nonetheless, it is a very good description of the behavior of objects in spacetime, under the geometrical interpretation of GR, to my understanding.
Not in so many words, no, but what else can you be implying?
That different paths in spacetime between point A and point B can arrive at the same spacetime point after traveling different distances in the time direction.
In order to better understand your position objecttions, could you tell me if you think distance can be measured with a degree or certainty or metaphysical clarity not available to the measuring of time, and if so, why you believe this to be the case?
But if the 7 represents my total bank accounts, the first number is the number of account in which I am overdrawn, and the second number represents the number of accounts which have in excess of $1,000,000, then 5 + 2 is clearly NOT equivalent to 2 + 5.
Absolutely, models only work until you find situations where they don't work.
One Brow said: "I agree, and I don't think you can analyze the position of Bob being stationary in SR, because it has machinery to discuss what happens to Rob in this viewpoint."
Of course SR "has the machinery." You simply treat Bob as the one who is "really" moving, instead of Rob. I can see that all that time I spent explaining why the twin paradox was no paradox so long as you were willing to abrogate the assumptions of SR itself was wasted.
One Brow said: "In order to better understand your position objecttions, could you tell me if you think distance can be measured with a degree or certainty or metaphysical clarity not available to the measuring of time, and if so, why you believe this to be the case?"
I inferred from one of your prior posts that you may have miscontrued my position on this topic, but I let it go at the time, because I wasn't sure. You said: "I'm perfectly comfortable with this notion that length and time can not be measured directly. I only object to a claim one can be and other can not."
Like you, I take the position that neither of them can be measured directly.
You may have misunderstood what I said about one being easier to understand to be a claim about certainty (which I wasn't making). I said:
"Because time is such an abstract, derivative (from motion and/or "change" in general), and slippery concept, I think the underlying point is more easily understood in terms of distance."
I meant no more than what I said. I think the point I was trying to make (which applies equally to both time and distance) is easier to understand in terms of distance. Mainly because the things we use to measure distance (objects in space) are directly perceivable, whereas time is not.
But I did not use "easier to understand" to mean that one is certain and one isn't, nor did I mean that distance is directly measured while time isn't. Distance, as distance, is no more and no less of an abstraction than is time, as time.
That said, no one can "see" a second. It is an intangible thing. On the other hand, one can see a yardstick.
Likewise, I can see two objects in space, but I cannot see two different point is time (I must infer them). But I can see both the keyboard and the monitor on my desktop.
I can't "see" the space in between my keyboard anymore than I can "see" the duration between two events. Nonetheless, the space has the illusion of being more tangible, because I can put a yardstick in it and "measure it." I can't physcially do that with a duration.
So, all in all, the components which go into the creation of the concept of distance are much more amenable to empirically-based manipulation and definition. In that sense you might say they are more "metaphysically" clear or more "certain." But that would only be if you thought empirical accessibility provided some special brand of clarity or metaphysical foundation, I spoze.
One Brow said: "One Brow said: "In order to better understand your position objecttions..."
All I'm sayin about the "position" of time is that it is an abstraction from an abstraction. Time itself has nothing to do with positions in space, at least not inherently, that I can see. I can take a simple piece of graph paper and plot time and occurences on a line. But the line axis on the graph reserved for time is hardly "time itself." You can take the concept of time and treat it geometrically, for analytical purposes, and I understand that. But when you start to talk about positions on a piece of graph paper as "reality" then I become a little confused.
The author who talked about Bell thought Bell was right and asked this question: "How does this material object get to know which type of spacetime—Galilean or Minkowskian, say—it is immersed in?"
I already gave my answer:
"One primary point here is that any instrument which is designed to count and measure something which it will "translate" into the measurement desired (whether it be time, distance, or anything else), will be based on certain assumption. Once programmed with it's assumptions, it will simply continue to apply them, in a mechanical, non-cognitive fashion. It does not re-adjust itself because it somehow knows that .89 mile is not a "real" mile or that 67.5 seconds is not a "real" minute.
It will tell you that sumthin which aint a mile is a mile without compunction, remorse, or conscience. I don't trust them lyin bastards, my own damn self, ya know?"
What's your answer, Eric?
Here's a guy who rejects SR on the basis of the thesis that so-called "matter" is actually a wave. Homepage is http://www.glafreniere.com/matter.htm
He may be right or wrong, but he has certainly put a lot of work into his website and seems to have a fair grasp on the physics concepts involved. After claiming that the doppler effect explains relativity, he claims that: "Lorentz's formulas just produce or correct a Doppler effect....The Lorentz transformations indicate that all this happens solely because of the Doppler effect. This strongly suggests that matter is undergoing the Doppler effect. Matter behaves like waves do. Lorentz's Relativity indicates that matter consists of waves propagating at the speed of light." http://www.glafreniere.com/sa_relativity.htm
I haven't read all this, but I wonder if this is accurate: "Lorentz's formulas just produce or correct a Doppler effect." If so, then the need for the transformations would seem to follow. In effect, they are needed to correct for the "optical illusions" created by other motion-based phenomena. I think this guy goes on to claim that "matter" (actually waves) creates its own doppler effect. He says:
"Relativity is all about mystification where the Doppler effect hides from our eyes what is really going on. This can easily be explained on the condition that matter and fields of force are made of standing waves, and that all forces such as light and gravity are also caused by waves. Clearly, any moving wave system should undergo the Doppler effect."
I'm not saying this guy is right (although many famous physicists have argued that matter consists of waves). But, either way, I wouldn't be the least bit surprised if the apparently unique behavior of light is ultimately found to be the result of misleading appearances created by some phenonemon which is currently overlooked or misunderstood.
I can understand why, if I rely on my watch once it starts running slow, I can readily be deceived into thinking that is 4:00 P.M. when it is actually 4:30. I can't understand the assertion that it really is 4:00 because my watch says so, and time is simply what my watch says it is.
Of course SR "has the machinery." You simply treat Bob as the one who is "really" moving, instead of Rob.
Which is not the point of view where Bob is stationary. I didn't say SR could not describe the situation, just that for one particular point of view, it did not have the tools needed. In particular, it has no theory regarding gravity, and gravity is what allows you to take the point of view that Bob is stationary (or at least inertial).
I can see that all that time I spent explaining why the twin paradox was no paradox so long as you were willing to abrogate the assumptions of SR itself was wasted.
That depends on your goal. I certainly understand your point of view better. I don't agree with your conclusions, so if that was your goal, then you probably won't get there.
Like you, I take the position that neither of them can be measured directly.
I find that to be a reasonable position, but it is not mine. I think rulers and clocks do measure distance (length and duration, respectively). However, I am willing to discuss using the assumption that they do not.
Distance, as distance, is no more and no less of an abstraction than is time, as time.
OK.
That said, no one can "see" a second. It is an intangible thing. On the other hand, one can see a yardstick.
A yardstick is not a yard. The movement of a second hand is not a second. You can see the yardstick and the movement, you can't see the yard or the second. Agreed?
Likewise, I can see two objects in space, but I cannot see two different point is time (I must infer them). But I can see both the keyboard and the monitor on my desktop.
Again, you can see different objects at the same time, and infer they are in different locations and separated by some length. You can see the same object at different times, and infer that some duration of time thas passed. That you need to make an inference in either case does not mean there would be no distance either case, absent your inference.
I can't "see" the space in between my keyboard anymore than I can "see" the duration between two events. Nonetheless, the space has the illusion of being more tangible, because I can put a yardstick in it and "measure it." I can't physcially do that with a duration.
That is what a clock does; it measures durations.
All I'm sayin about the "position" of time is that it is an abstraction from an abstraction. Time itself has nothing to do with positions in space, at least not inherently, that I can see. I can take a simple piece of graph paper and plot time and occurences on a line. But the line axis on the graph reserved for time is hardly "time itself." You can take the concept of time and treat it geometrically, for analytical purposes, and I understand that. But when you start to talk about positions on a piece of graph paper as "reality" then I become a little confused.
I agree that graphs like this are abstractions that allow you to model the behavior of time, and not time itself, much like they allow you to model space, and are not space itself.
It will tell you that sumthin which aint a mile is a mile without compunction, remorse, or conscience. I don't trust them lyin bastards, my own damn self, ya know?"
What's your answer, Eric?
I agree they will continue to operate as the always have, mechanically and without interruption. Further, the yardstick/clock doesn't need to know what sort of space it is in, it can and will operate the same locally regardless of any changed in inertial conditions.
Here's a guy who rejects SR on the basis of the thesis that so-called "matter" is actually a wave.
He could well be right. We like to think of particles and waves as being separate categories, but reality has a way of ruely correcting us.
But, either way, I wouldn't be the least bit surprised if the apparently unique behavior of light is ultimately found to be the result of misleading appearances created by some phenonemon which is currently overlooked or misunderstood.
Remove "misleading appearances created by", and I have no doubt the statement is true.
I can't understand the assertion that it really is 4:00 because my watch says so, and time is simply what my watch says it is.
No one is claiming that, AFAICT.
One Brow said: "Which is not the point of view where Bob is stationary. I didn't say SR could not describe the situation, just that for one particular point of view, it did not have the tools needed. In particular, it has no theory regarding gravity, and gravity is what allows you to take the point of view that Bob is stationary (or at least inertial)."
I have no idea what you're saying, in terms of the wiki examples. In the "solution" to the twin paradox, both the SR and GR explanations (as well as the one based on doppler effects) take the view the the spaceship twin is moving away, then returning. Without that assumption they cannot give the explanation they give. If you reverse the assumption (earth is moving, then returning; spaceship remaining motionless), the exact same explanation will apply, in reverse, and the earth twin will be younger. If the premise is that you cannot tell which one is moving, then the "answer" would have to be: "OK, then we can't tell you who is really younger."
Each "sees" the other as travelling, they wiki says, but in fact one is making a journey and one isn't. "A twin who makes a journey into space in a high-speed rocket will return home to find he has aged less than his identical twin who stayed on Earth."
Wiki goes on to say why all the "explanations" (GR, SR, or whatever) work: "there have been numerous explanations of this paradox, all based upon there being no contradiction because there is no symmetry — only one twin has undergone acceleration and deceleration, thus differentiating the two cases."
Only one (the moving one) has undergone acceleration and deceleration--and that one is the one who is "on a journey" (and is younger) and it is not the one who "stays home" (remains motionless, and is older).
Wiki simply misstates the nature of the paradox, and misrepresents the nature of the so-called "solution." They phrase the issue as "How can an absolute effect (one twin really does age less) result from a relative motion?" The "solutions" they give are not based on true relative motion. Even with absolute motion, each twin is moving relative to each other. The concept that "all" motion is relative goes way back to, as has been accepted as accurate since, Galilleo, when absolute time and space were presupposed.
The real "paradox" only arises when the claim is made (as you did) that both twin's observations are "correct," i.e. that each is younger than the other. It is not a paradox to say that one is younger than the other. Nor is "relative motion" being used to solve the problem in wiki's entry. They are saying one twin is "absolutely" moving relative to the other (non-travelling) twin.
Here is another "solution" of the problem which tries to cheat by equovicating:
http://mentock.home.mindspring.com/twins.htm
This guy freely concedes that if you reversed the situation the earth twin would be younger:
"Now, since special relativity lets us use either rest frame, we assume Bob is the at-home twin. Ann speeds away at 3/5c....If we allow Ann to return, we've only restated the problem with the names switched. In the first version, Ann stayed in an inertial frame, and she must stay in an inertial frame in this version. Bob zooms off after Ann at 15/17 light speed..."
"Ann" is the earth twin. This guy will NOT allow her to return, even if she moves away (so he requires the other guy to accelerate to catch up instead of truly reversing the situation. He won't allow her to return because then she would be younger, and that's not the result he wants to reach.
So in the "ann is the one moving" part of his "solution" both of the twins partake of "absolute motion," just at different speeds. Well, aint that special, eh?
I said: "The concept that "all" motion is relative goes way back to, as has been accepted as accurate since, Galilleo, when absolute time and space were presupposed."
To elaborate, "all" motion is relative to a frame of reference. For Galilleo if a guy threw a ball on a ship, the ball was "really" moving. That is what I'm calling "absolute motion" above--the ball is really is moving, relative to the ship, and it wasn't that the ball stopped when it left his hand and the ship started moving away from it.
An observer on the shore would (in virtually every case) also see that ball as moving. It's just that they would see the speed and trajectory of the the ball differently. That is what "relative motion" means in the traditional sense.
Relying on different frames of references to "explain" special relativity does not in any way distinguish it from LR or Galliean relativity. That is not what makes SR what it is.
I said: "He won't allow her to return because then she would be younger, and that's not the result he wants to reach."
The result that he wants to reach is the same one you want to reach--i.e., that either way the same twin is younger. But notice that he can't do that by relying on the wiki explanation. He has to change the whole hypothetical and denies your claim that, in the wiki example, the same twin would be younger even if you reversed the assumed patterns of absolute motion.
Yet another explanation of the twin paradox makes exactly the point I am making:
"Did time slow down for Stella, making her years younger than her home-bound brother? Or can Stella declare that the Earth did the travelling, so Terence is the younger? Not to keep anyone in suspense, Special Relativity (SR for short) plumps unequivocally for the first answer."
Why is this? Because: "Stella's frame is not inertial while she is accelerating. And this is observationally detectable: Stella had to fire her thrusters midway through her trip; Terence did nothing of the sort. The Ming vase she had borrowed from Terence fell over and cracked. She struggled to maintain her balance, like the crew of Star Trek. In short, she felt the acceleration, while Terence felt nothing."
In other words, because Stella is the one really moving, not Terence. Of course this was postulated when the guy set up the "problem" when he said: "Terence sits at home on Earth. Stella flies off in a spaceship at nearly the speed of light, turns around after a while, thrusters blazing, and returns."
http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_intro.html
Just so you don't once again miss the implications, let me repeat this part again:
"Or can Stella declare that the Earth did the travelling, so Terence is the younger?"
He is implicitly saying that IF the earth was moving, then Tereance (earth twin) WOULD be younger. He simply denies that the earth was (or could properly be considered to be) the thing which was "really" moving.
I said: "Wiki simply misstates the nature of the paradox, and misrepresents the nature of the so-called "solution." They phrase the issue as "How can an absolute effect (one twin really does age less) result from a relative motion?"
I am really just going to repeat what I said above, here, but in a slightly different and somewhat qualified way. Wiki say the issue is: "How can an absolute effect (one twin really does age less) result from a relative motion?"
I said wiki misstates the nature of the paradox, but let me retract that. I suppose this is one way to state the paradox, even if it isn't the one I would choose. Wiki does in fact misstate the nature of the "solution" it proposes, however.
To solve the problem, wiki would have to show how an absolute effect can result from a relative motion. They do NOT do this.
They merely show how an abolute effect can result from an absolute (not relative) motion, which is not a problem to do nor a paradox once solved.
Again, "relative" in the sense wiki uses it in formulating the problem is not mere "galliean relativity." They mean "special relativity," but that is not what they use in the "solution."
I said: "I can't understand the assertion that it really is 4:00 because my watch says so, and time is simply what my watch says it is."
You said: "No one is claiming that, AFAICT."
Of course no one is claiming that would be the case in the example I gave, and I didn't mean it literally in that particular case, just funnin. But I was making, in a fun way, legitmate point by analogy.
In my example, I have presupposed an inaccurate clock, which was inaccurate to do MALFUNCTION. SR does not say that a malfunctioning clock will be corrected by time. But it does, in effect, say that all properly functioning clock are accurate even if they give radically different readings of time in different "frames of reference." Likewise, in effect, it says that clocks from other intertial frames of reference would be "automatically" corrected to agree with the frame of reference it was moved to, so that it would agree (at least henceforth) with the clocks which previously gave a different reading than it did.
Underlying the whole thing is basically this (as I said at the beginning here): the "correct" time is what a (properly functioning) clock says it is. If that varies from what properly functioning clocks in other frames of reference say it is, then it is still right, as is the one which reads differently in another frame of reference.
This is what I have called "putting one's faith in yardsticks" in other posts.
Turning one last time to the "twin" paradox as it relates to Chris and Dis (or whatever you called them).
As I understand SR, time "really does" slow down for a moving object, and the more radically so the the closer it gets to the speed of light. So, with respect to Chris and Dis, the (conditional) answers, if consistent with the wiki premises, would be:
1. If Chris is moving faster than Dis, then Chris is younger
2. If Dis is moving faster than Chris, then Dis is younger.
3. If it cannot be determined who is moving faster, then it cannot be determined who is younger.
The "paradox" arises because SR wants to throw in the claim that:
4. The observations (of his measuring instruments) for each "twin" are correct. According to them, each sees the other as younger.
This leads to the paradoxical conclusion that each one "really is" younger than the other.
Meant to say: "In my example, I have presupposed an inaccurate clock, which was inaccurate due to [not "to do"] MALFUNCTION."
One Brow said: "A yardstick is not a yard. The movement of a second hand is not a second. You can see the yardstick and the movement, you can't see the yard or the second. Agreed?"
Yes, I agree, and said as much in my post. I wasn't trying to make the point that a yardstick is a yard.
From this sounds of this, it's not apparent that you yourself agree with your statements quoted in the prior post though:
One Brow said: "I think rulers and clocks do measure distance (length and duration, respectively)."
Either that, or you are changing my claims. The claim I made, and assumed you agreed with, was: "Like you, I take the position that neither of them can be measured directly."
So did you really mean: "I think rulers and clocks do [directly] measure distance (length and duration, respectively)." If so, in what sense are you calling the measurement "direct?"
By indirect, I merely meant that there are intermediate processes and assumptions involved in me laying a yardstick on a floor and then claiming that the distance it is covering is "one yard." It is direct in the sense that you just lay the thing on the floor and say "that's it, that's a yard," but that is not what I meant when I said it is not "direct." How do you mean that it is direct? Is there any sense in which you would say the measurements are not direct?
Heh, now we're back to Van Flandern's chiding about the absurdity of the GR "explanation" of the paradox, with a different physicist doing the explaining:
"Relativity puts an upper on speed, but no upper limit on acceleration. An instantaneous Turnaround Event is the limiting case of shorter and shorter turnarounds, and so the theory should handle it...The Turnaround Event is instantaneous. Total Terence ageing: less than 4 months, it would seem. Yet Terence is supposed to be over 14 years older when Stella returns! Where did the missing time go?
...The Outbound reference frame says: "At the same time that Stella makes her turnaround, Terence's clock reads about two months." The Inbound reference frame says: "At the same time that Stella makes her turnaround, Terence's clock reads about 13 years and 10 months." The apparent "gap" is just an accounting error, caused by switching from one frame to another."
http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_gap.html
Heh, no real gap, but just a mere "accounting error," eh? The guy supposedly ages almost 14 years in an "instant," and this is supposed make some practical (as opposed to mathematical) sense? I don't think so! Homey don't play dat.
And, in my book, anyone who does simply equates math with "practicality," the sure sign of a nerd without a lick of street cred, ya know?
Last night my great-great grandbaby, Pasty Gansta, asked me to look over his first grade math homework. Everything looked right, except question #7. It asked: 8 + 3 = ____. He put in "10" as the answer. After that it kinda went like this here:
Me: Pasty, look at #7 again. Ya sure that's right? He looked at it a spell...
PG: Yep. Absolutely, positively sure. 8 + 3 = 10, sho nuff. It's a lead pipe cinch.
Me: What is 8 + 1?
PG: 9
Me: What is 9 + 1?
PG: 10
Me: What is 1 + 1?
PG: 2
Me: So what is 8 + 2?
PG: 10
Me: what is 10 + 1?
PG: 11
Me: So what is 8 + 3?
PG: 10
Me: You don't understand what I'm saying then. You don't understand what you are saying.
PG: I understand perfectly what you are sayin. And don't even try to tell me I don't understand what I'm sayin. You're trying to say 8 + 3 = 10. I understand that, I just don't agree.
I thought on it a spell, and then it became obvious. Somebody needs to beat some damn sense into this little bastard. So I backhanded his sorry ass. Hard.
Pasty went runnin off, cryin, and my job was done. That oughta learn him, I figure.
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