Frame of Reference as Subject in Subjective Idealism

[Iggy]

Feel free to specify fractions down to 1/32nd of the track if you like

Someone already did that for you in post #280.

 

With an IQ of 200, or whatever you said, you should be able to answer questions like "if light goes twice as far as a ship then what fraction of their distances combined does light go?" while playing a banjo and juggling three cats.

[Schrödinger's hat]

With an IQ of 200, or whatever you said, you should be able to answer questions like "if light goes twice as far as a ship then what fraction of their distances combined does light go?" while playing a banjo and juggling three cats.

 

To be fair, one would either have to be incredibly intelligent or incredibly, belligerently stupid to keep this many physicists/physics students/etc responding for this long when it clearly hasn't achieved anything so far.

[Iggy]

or the forum has an unending supply of unrequited helpfulness and assistance... yeah, let's go with that

 

In any case, I took us off topic. Sorry. What was the velocity of light relative to one of the ships in the last thought experiment? If a rod stuck out of the nose of one of the ships that was 2/3rds of an AU long would it take 2/3rds of 8.3 minutes for the light to reach the end? I do hope so for realism's sake.

[owl]

This thread is appropriately in the philosophy section because it contrasts realism with idealism vis-a-vis relativity theory, specifically the concept that frame of reference, as in “there is no preferred...” determines “reality” in the same sense as subjective perception, with the difference that no actual person or subject need be present at any given frame of reference (FOR). My primary illustration of FOR as such a qualified “subject” in subjective idealism has been relativity’s claims about of length contraction.

 

Since thought experiments are well accepted in relativity theory, I proposed one in support of realism as debunking length contraction. I was told that length contraction is irrelevant to this thread's argument, by a physicist. I replied it was very relevant, but the Cap ‘n (admin.) supported the physicist as a valid arbiter of such relevance or lack theerof. Though I did teach university level (undergraduate) “Logic and the Scientific Method” as part of a “Philosophy of Science” curriculum, I am told that basically physics trumps philosophy here even in the philosophy section, so, therefore length contraction is irrelevant here because a physicist says so.

 

The above physicist (Schrodinger's hat) had previously said that my above thought experiment made no sense to him.

It is really very simple. If there were no intelligent life measuring things and the distances between them, would they still have an objective existence and intrinsic properties or not? An idealist will claim that reality depends on how it is perceived, while a realist will grant that “the world” in most general terms exists “as is” with or without perception and measurement of it from different FORs.

 

So, the realist will (and I did) disagree with the relativity theorists who claim that the shapes of things, for instance, depend on the FOR from which they are observed or measured. Cap ‘n R presented some thought experiments of his own to illustrate that a severely oblate spheroid describing the shape of Earth is just as valid as a nearly spherical Earth, because of length contraction as observed from an extremely high speed FOR, since “there is no preferred FOR." Another of his arguments was a metaphor of Earth as a statue seen from different angles (backside vs frontal view), like Earth as seen from the above extreme FOR.

 

Then we have the distances between objects in the cosmos, starting close to home with our solar system. A realist like me say that the distance between Earth and Sun, for instance, does not actually vary with the FOR from which it is observed, but only with Earth’s position in its elliptical orbit. I also say that Earth’s atmosphere does not actually vary in depth (distance through it) with the FOR of an incoming muon, for instance, an often cited argument for length contraction, as in “for a muon... it’s way less than the standard 200 or so miles.”

And, btw, all the above “realism” does not require that the speed of light be variable. My last thought experiment in that regard kept lightspeed constant even as the observers proceeded at 1/2 lightspeed with their lasers going ahead at ‘C.’ The velocity of light does not increase when fired ahead from a rocket going 1/2 lightspeed. Light can not be “pushed” faster than ‘C,’ and the one Au “track” hosting the experiment does not change lengths (contract) during the 5+ minutes each observer travels before seeing the other’s light. (Iggy constantly misrepresents me... I don’t know whether intentionally or because he almost always misunderstands what I am saying. I think the latter, from past experience.)

 

My objection to the relativity of simultaneity is also based on realism. Regardless of clocks and clocking all things everywhere are happening now, regardless of location or who sees what and when from different FORs. “Now” still means “the present.” Now IS the present. Location of events/objects does not dictate what “now” means, as relativity insists.

 

Anyway, I hope this helps to clarify what this thread is intended to be about.

Ps: All snide remarks about me recently degrade the quality of this site into the "personal attack" mode, rather than respectful exchange of ideas about science and the philosophy thereof, however much we disagree. Just sayin'.

Edited September 23, 2011 by owl

[Cap'n Refsmmat]

My objection to the relativity of simultaneity is also based on realism. Regardless of clocks and clocking all things everywhere are happening now, regardless of location or who sees what and when from different FORs. “Now” still means “the present.” Now IS the present.

How do you know?

 

Location of events/objects does not dictate what “now” means, as relativity insists.

No, it doesn't. Relative location has nothing to do with it. Where did you get that idea?

[owl]

This is an afterthought on Iggy’s intentions, aside from the content of science debate here, and before reading replies since my last post. (Soon)

I gave him the benefit of the doubt, that he simply does not understand what I am saying here. But then I realized that I had given him my exact IQ scores*, since he seemed to think I was exceptionally stupid. (*SBIS; 170 and WAIS 178.) So he intentionally exaggerated the above as a 200 IQ. As a psychologist I can only assume that he was misrepresenting my IQ intentionally to influence readers to believe that I am a liar.

 

Malice is quite different than stupidity. I would appreciate the administration’s attention to this kind of harassment.

Thanks.

[Schrödinger's hat]

Ps: All snide remarks about me recently degrade the quality of this site into the "personal attack" mode, rather than respectful exchange of ideas about science and the philosophy thereof, however much we disagree. Just sayin'.

I apologise, I was a bit frustrated, my comment was out of line. Glad that you refused to rise to it.

 

 

This thread is appropriately in the philosophy section because it contrasts realism with idealism vis-a-vis relativity theory, specifically the concept that frame of reference, as in “there is no preferred...” determines “reality” in the same sense as subjective perception, with the difference that no actual person or subject need be present at any given frame of reference (FOR). My primary illustration of FOR as such a qualified “subject” in subjective idealism has been relativity’s claims about of length contraction.

You're conflating a couple of different ideas again. There are more than two concepts that apply here.

 

No known preferred reference frame (experiments done to determine the laws of physics on a moving space-ship are just as valid as, or at least indistinguishable from those on earth)

Presentism (ie. the universe is 3d and defined only in the now)

Speed of light that will be measured as unchanging between different reference frames (ie. it's a law of physics).

Realism

 

These four concepts are incompatable. You are assuming the second, and projecting that assumption onto us. This leads you to conclude that we are not realists, or are being logically inconsistent.

 

 

With the laser jousters thought experiment, and Capn's earlier attempts we were hoping to show you some of the logical consequences of takin

 

Since thought experiments are well accepted in relativity theory, I proposed one in support of realism as debunking length contraction. I was told that length contraction is irrelevant to this thread's argument, by a physicist. I replied it was very relevant, but the Cap ‘n (admin.) supported the physicist as a valid arbiter of such relevance or lack theerof. Though I did teach university level (undergraduate) “Logic and the Scientific Method” as part of a “Philosophy of Science” curriculum, I am told that basically physics trumps philosophy here even in the philosophy section, so, therefore length contraction is irrelevant here because a physicist says so.

Philosophy, or rather philosophy that pertains to reality, must be compatable with physics.

Capn and I have been trying to guide you towards a logical conclusion that follows from the assumption that the speed of light is measured as the same by all experimenters (moving or non-moving).

This conclusion is incompatable with (my understanding of) the assumptions you have stated.

 

The reason I was trying to take the discussion away from length contraction is that it is a logical consequence of non-simultaneity. If you do not accept relativity's version of simultaneity then any discussion over length contraction is completely moot. Again, the thought experiments were intended to show you how it is derived, and provide an opportunity for you to query the assumptions on which it's based.

 

The above physicist (Schrodinger's hat) had previously said that my above thought experiment made no sense to him.

...

 

...

And, btw, all the above “realism” does not require that the speed of light be variable.

None of that addressed the speed of light in different frames of reference. All I can gather from that is 'here is a description of some things happening'. The cases where the logic behind SR (agreement between observations in different frames of reference) were not included.

 

Also I would not (yet) consider the title of physicist as entirely appropriate in all contexts, as I have not finished my degree.

 

My last thought experiment in that regard kept lightspeed constant even as the observers proceeded at 1/2 lightspeed with their lasers going ahead at ‘C.’ The velocity of light does not increase when fired ahead from a rocket going 1/2 lightspeed. Light can not be “pushed” faster than ‘C,’ and the one Au “track” hosting the experiment does not change lengths (contract) during the 5+ minutes each observer travels before seeing the other’s light. (Iggy constantly misrepresents me... I don’t know whether intentionally or because he almost always misunderstands what I am saying. I think the latter, from past experience.)

 

My objection to the relativity of simultaneity is also based on realism. Regardless of clocks and clocking all things everywhere are happening now, regardless of location or who sees what and when from different FORs.

I tried to respond to that. See the diagram in #399. It is intended to represent this scenario.

 

In case it's still a bit unclear, read it by imagining a thin horizontal slice, each slice represents a different moment in time, as if someone was observing the rockets (and knew exactly where they were at each moment in time -- by maths or magic or whatever.) and just recording the positions of things at each moment of time.

 

The blue dots will be our jousters, the red is where the front of the beams of lights are.

 

Is this clear? Does it match what you were trying to explain?

 

“Now” still means “the present.” Now IS the present. Location of events/objects does not dictate what “now” means, as relativity insists.

This is the philosophy of presentism. In relativity 'now' is simply a name for a set of events. Much like 'yesterday', and similar in many respects to 'left' (note that spatial position has nothing to do with it).

 

 

At any rate. Ignore this issue, and everything else I've said for the moment and focus on the jousters scenario. I just want to examine the logical consequences of this thought experiment. I am not assuming anything about length contraction or simultaneity, just trying to describe the situation you outlined.

[tar]

Iggy,

 

Perhaps I should have run with it, but that would have been disingenuous, which would be unhelpful to the discussion, and unhelpful to my goal of actually having the insights required to understand what is "meant" here.

 

And I like Schrodinger's hat's idea of "figuring out" the puzzle, rather than pretending there is none. And I would be happy to accept the findings of all the 180 IQ folks that have been working this for the last century plus, if I knew what the heck they "meant".

 

So I read your link, and pulled a book off my shelf (that I actually think I had read or attempted to read 15 years ago) called The Principle of Relativity, with collected original papers on the subject by Einstein, Lorentz, Weyl and Minkowski.

 

Still...as clear as mud.

 

Know a little more than I did yesterday about Gausian coordinates, Minkowski four space, Lorentz transforms and Einstein's thoughts on the matter, but still consider time a different sort of thing than space.

 

There is something I have noticed about "now" that I cannot readily see is woven into the assumptions and equations.

 

That is, that other "me"s seem to be always in the same one that I am in. Today, I am at a different t coordinate than I was yesterday...but look at that...so are you. Your t coordinate was at 0 yesterday, and so was mine. And look here, we are both at t0 again today. We never leave t0. It's always now. Yet time passes, and there is no going back.

 

Space on the other hand sticks around. I can go to work, come home, go to work again. The earth can rotate on its axis and face the sun then the stars then the sun again. The sun can orbit the center of galaxy the galaxy can merge with or dance around or away from its neighbors.

 

Years ago I passed under a train bridge and thought about the cement of the abuttment having been there for years, even though it was made up of mostly empty space...orbiting electrons and neutrons made of quarks and spins and fields and forces, yet undoubtably a solid cement and steel structure.

 

Its still there. I saw it the other day.

 

However, the other day is at -t now. It no longer exists.

 

Regards, TAR2

Edited September 24, 2011 by tar

[Iggy]

As a psychologist I can only assume that he was misrepresenting my IQ intentionally to influence readers to believe that I am a liar.

Malice is quite different than stupidity. I would appreciate the administration’s attention to this kind of harassment.

Thanks.

If you appeal to your own authority, like so:

 

Finally, as to what "puts me in" such a position to criticize time dilation, length contraction and spacetime curvature... Heredity. Inherited genes.

I am a free thinker with a measured IQ of 170 (SBIS); 178 (WAIS.)

you put yourself in the position of having that authority debunked. I'm sorry if debunking it feels malicious. I actually think it is helpful for you because if you realized that you don't understand the basic concepts of relativity then nothing would prevent you from amending misconceptions like you repeated again today...

 

Location of events/objects does not dictate what “now” means, as relativity insists.

You wouldn't be bound to these idées fixes that persist even after you've been corrected on them about a dozen times. That would just be swell.

 

Iggy,

 

Perhaps I should have run with it, but that would have been disingenuous, which would be unhelpful to the discussion, and unhelpful to my goal of actually having the insights required to understand what is "meant" here.

 

Amen! I admire your intellectual honesty.

 

And I like Schrodinger's hat's idea of "figuring out" the puzzle, rather than pretending there is none. And I would be happy to accept the findings of all the 180 IQ folks that have been working this for the last century plus, if I knew what the heck they "meant".

 

Understood.

 

So I read your link, and pulled a book off my shelf (that I actually think I had read or attempted to read 15 years ago) called The Principle of Relativity, with collected original papers on the subject by Einstein, Lorentz, Weyl and Minkowski.

 

Still...as clear as mud.

 

Know a little more than I did yesterday about Gausian coordinates, Minkowski four space, Lorentz transforms and Einstein's thoughts on the matter, but still consider time a different sort of thing than space.

 

I'm glad to hear you read the link and sorry to hear it isn't coming together for you more.

 

There is something I have noticed about "now" that I cannot readily see is woven into the assumptions and equations.

 

That is, that other "me"s seem to be always in the same one that I am in. Today, I am at a different t coordinate than I was yesterday...but look at that...so are you. Your t coordinate was at 0 yesterday, and so was mine. And look here, we are both at t0 again today. We never leave t0. It's always now. Yet time passes, and there is no going back.

 

Space on the other hand sticks around. I can go to work, come home, go to work again. The earth can rotate on its axis and face the sun then the stars then the sun again. The sun can orbit the center of galaxy the galaxy can merge with or dance around or away from its neighbors.

 

Years ago I passed under a train bridge and thought about the cement of the abuttment having been there for years, even though it was made up of mostly empty space...orbiting electrons and neutrons made of quarks and spins and fields and forces, yet undoubtably a solid cement and steel structure.

 

Its still there. I saw it the other day.

 

However, the other day is at -t now. It no longer exists.

 

Regards, TAR2

 

You might compare time in relativity to a calendar. Nowhere on a calendar do you see "now" written. Would this mean to you, I'm asking honestly and I'm curious, that the calendar is somehow at fault or is misleading in how it represents time? I'm just trying to get a grasp on what you mean.

[md65536]

(*SBIS; 170 and WAIS 178.) So he intentionally exaggerated the above as a 200 IQ. As a psychologist I can only assume that he was misrepresenting my IQ intentionally to influence readers to believe that I am a liar.

I searched for those values to ascertain their meaning and I came across another user on various forums who has the exact same IQ scores.

 

This other user has been banned from scienceforums.COM, sciencechatforum.com aka philosophychatforum.com, and possibly the Genius Forums and myspace.

 

I found this post from a staff member of one of the sites especially interesting:

The fact that you have multiple "stalkers" roaming the Internet, warning the innocent of your checkered past is not at all surprising. I'm even considering the possibility of becoming a "stalker" myself, such as the one who informed us of you. I would certainly have the satisfaction of knowing I was helping to build a better world, opposing the agents of superstition, ignorance and delusion. I would also like to put together a "training" presentation that I can take from website to website, showing the newbies and the innocent how to spot TWATs -- Trolls, Whackos and Thumpers. I have a vision that in a few years, I might help educate the SCILLs (Scientifically Curious, Intelligent and Logically Lucid) to recognize the signature behavior of TWATs, and to band together so that no foothold is allowed for their contagion.

This other user seems to roam from site to site over the years, pissing off a lot of people trying to "enlighten" them with the same crap over and over, wasting a lot of people's time getting into similar closed-minded arguments. He, too, is also a psychotherapist, but only with "a private practice by word of mouth with no advertising and no listing", so I assume no license or doctoral training.

 

My point is that high IQ is not credentials.

[Schrödinger's hat]

Know a little more than I did yesterday about Gausian coordinates, Minkowski four space, Lorentz transforms and Einstein's thoughts on the matter, but still consider time a different sort of thing than space.

Well we do distinguish between timelike things (which can carry causality, although forward and backward causality are not really distinct) and spacelike things (which don't involve causal links).

There is something I have noticed about "now" that I cannot readily see is woven into the assumptions and equations.

 

That is, that other "me"s seem to be always in the same one that I am in. Today, I am at a different t coordinate than I was yesterday...but look at that...so are you. Your t coordinate was at 0 yesterday, and so was mine. And look here, we are both at t0 again today. We never leave t0. It's always now. Yet time passes, and there is no going back.

 

I don't think the concept of 'now' is really present as a first class entity in SR. As I said, we have to look to other scientific theories (thermodynamics, quantum etc) to gain insight here.

Relativity, much like classical mechanics has nothing to say on the matter.

 

Once you bring entropy into the picture there's a good reason why the me from yesterday doesn't remember today, but it still doesn't really answer why I perceive being this me rather than yesterday's me.

This issue is still well within the realm of philosophy, and somewhat tangled with the problem of measurement.

 

One thing that may be a good starting point is to imagine some kind of 3d steady-state computer that can only carry information east.

If you were to construct an AI on such a computer, then wander east for a while until you reach a point where it has learned a bit about itself.

At that position you can set up some input so as to ask it a question about what 'moment' (amount of east-ness) it perceives itself to be at.

It won't remember anything further east so it will form answers based on that position and things further west.

 

This is somewhat of a distinct concept, so perhaps a new thread might be appropriate if you want to discuss this further.

[Iggy]

I don't think the concept of 'now' is really present as a first class entity in SR. As I said, we have to look to other scientific theories (thermodynamics, quantum etc) to gain insight here.

I agree, and I think an important point is that the concept isn't incompatible with relativity -- just isn't necessary.

 

I recalled reading a good augmentation to what Tar was saying and it wasn't hard to find so I'll post it:

 

It is all very well saying that all that exists is what is happening at the present instant, what exactly do you mean by that? Presumably you mean ‘me reading this book in this particular location’. Fair enough. But I imagine you would also include what is happening elsewhere (literally elsewhere) at the present instant. For example, there might be a man in New York climbing some stairs. At the present instant he has his foot on the first step. So, you will add him, with his foot on that step, to your list of existent entities. But now suppose there is an astronaut flying overhead directly above you. Because of the loss of simultaneity of separated events, he will disagree with you over what is happening simultaneously in New York while you are reading this book. As far as he is concerned, the man in New York, at the present instant, has his foot on the second step – not the first step. Moreover, a second astronaut flying in a spacecraft travelling in the opposite direction to the first arrives at a third conclusion, namely at the present instant the man in New York hasn’t even reached the flight of stairs yet. You see the problem. It is all very well saying that ‘all that exists is what is happening at the present instant’, but nobody can agree as to what is happening at the present instant. What exists in New York? A man with his foot on the first step, or a man with his foot on the second step, or one who has not yet reached the stairs? As far as the block universe idea is concerned, there is no problem: all three alternatives in New York exist. The argument is merely over which of those three events in New York one chooses to label as having the same time coordinate as the one where you are. Relative motion means one simply takes different slices through four-dimensional spacetime as representing the events given the same time coordinate, ‘now’.

 

But of course, the block universe idea also has its problems. Where does the perceived special nature of the moment ‘now’ come from, and where do we get that dynamical sense of the flow of time? This is a big unsolved mystery, and might remain that way for all time. It does not seem to come out of the physics – certainly not from the block universe idea – but rather from our conscious perception of the physical world. For some unknown reason, consciousness seems to act like a searchlight scanning progressively along the time axis, momentarily singling out an instant of physical time as being that special moment we label ‘now’ – before the beam moves on to pick out the next instant to be so labelled.

 

But now we are venturing into the realms of speculation. Let’s get back to relativity.

 

Relativity - A Very Short Introduction

 

The last line is excellent advice But I would add that I believe philosophy and psychology are currently quite well suited to answer the question of why 'now' seems so important to human consciousness.

[tar]

Iggy and Schrödinger's hat,

 

My argument is not that my now is the only now that exists. Indeed quite the opposite. Each of us has our own, and we get it because we are at one place and one time.

 

Where this conception or understanding relates to this thread, is that we also have the ability to put ourselves in the shoes of another experiencing a different here, or a different now, or indeed remember ourselves in a past here and now, or even project ourselves or others into possible future moments and locations, and even impossible or made up moments and places.

 

Relativity attempts to describe the way that reality IS. In this, what t0 means, is of utmost importance. To say SR does not have this as a primary concern is somewhat why I have difficulty understanding what SR is using as t0. Is it the now of a human, on Earth?

 

I have no doubt that the equations and matrices "work out". Where I have difficulties is in carrying out the analogies, without understand the exact nature of each of the enities being represented by the variables. If I am not sure of, or do not agree with, or do not understand what exactly is being considered, how am I to know what it would mean to take the derivitave of it, or cut it in half, or multiply it, or indeed if these operations can even be carried out with the entity, much less imagine what it would mean.

 

Many things work out in one's mind, but don't work out when tried in reality.

 

After all, you can take the square root of 4 cows and get 2 cows. But if you take the square root of 2 cows you get 2 dead cows or a lot of hamburger and squaring the result will not get you two live cows back.

 

Some of the operations with x,y,z,t and x',y',z',t' can only be done if you use the the square root of -1, which is an "imaginary" number that means absolutely nothing, or anything you want. I would venture to say that this operation can only be done in the mind of a mathematician, and need not, indeed does not reflect anything really happening in objective reality. Objective reality is rather certain about what it does and it always works out, and fits together flawlessly.

 

So back to relativity. The order of the events of me sitting down, and the man taking the first step would not have to have an astronaut or two to be variously determined. We need only take the vantage point of a stationary woman tieing her sneaker, halfway between me and the man on the stairs. My conception of now determines the order she sees. If my conception of simultaneous is "when the man and I are as old as the universe" then she will see me sit and the man step simultaneously, but sometime after we both do the deeds. If I conceive of now as the moment we are both seen by her, I would have to put myself in her shoes, sometime in the future and concede that the now I am considering now depends not on the motion of the nows I am putting myself in the shoes of, but on their distance from me.

 

Nobody's subjective now "actually" coincides from an objective point of view. We (each here and now) achieve the age of the universe simultaneously, but what the rest of the universe did at that moment does not arrive here til some time later, depending on the distance and the speed of light.

 

So there is this now and there is that now, and they both exist but if you ever consider them equal, and put them both in an equation as t0, you are already off, by the distance between them. If the distance between two nows is not considered in the equation then the equation is not going to reflect reality. The mere "speed of moving" should not change the relationship. What should change the relationship, is movement toward or away.

 

And both the now of the object and the now of the subject proceeds "simultaneously" so that the here and now of each must be reassesed not only with each tick of each clock, but with any change of position and distance between them, based on an understanding that the nows will get closer in time as they near, and farther away in time as they receed.

 

So it depends mightily on what now we are considering, or any equation involving time is suspect.

 

Iggy,

 

A calender on the wall of the spaceship would look exactly the same to the traveling twin on her way to Alpha Centuri, as it did when she took it off her brother's wall at home. According to me, she could still use it. According to SR, it wouldn't work.

 

Regards, TAR2

 

P.S. She could use either her watch and mark off every 24 hrs, or she could watch the Earth and mark off every time her home town went from dark to light. The two methods would not coincide, should she have taken two calanders, one for each method, until her return. Her home town would take much more than 24 to make the transitions on the way out and much less than 24hrs on the way back.

[Schrödinger's hat]

Tar, I think you might still be getting hung up on the idea that light delay is linked to the definition of now.

The non-simultaneity does not come from signal delay, it comes from the assumption that there is a speed (whatever entity travels at that speed) that does not change when measured in different frames.

I am trying to get to this derivation in my present discussion with Owl.

The equations that are derived only have the t coordinate changing between different frames for events that are far away, but this is not linked to light delay.

As an analogy, imagine a table or flat plane. This defines a set of positions at a constant z (or up) coordinate.

Merely moving along the table will not change your z coordinate, or your perception of the z coordinate of other points, but if you tilt the table, then different points in space will be different coordinates.

 

As you see, if you tilt to your right, things to your right will become higher (or later for the Lorentz transform) than they were before, depending on how far away they are.

This is almost exactly how the lorentz transform works, but the geometry is a little bit different (you wind up with a minus sign in some places).

 

It might help to play with this for a little bit. Select the demo Han and Greedo to get one with some stuff at different positions.

Don't unpause it, press t to display some time information then scroll down to the x vs t diagram.

The horizontal white line in the middle represents what is happening 'now' in the frame that matches the stationary cross.

No matter where you are along this line you still see the same now. Unless you also accelerate.

To fall back to my table analogy you could move along the table as much as you liked, nothing would change height, but if you rotated the table about your new position things (far away from your new position) would change height.

Play with accelerating left and right (a and d, you still don't need to un-pause it). You'll see things that are a long way in time, but not in space wind up far away in space as well (because you are now moving away from them). In much the same way things that are far away in space (but at the same time) become far away in time.

 

The light delayed signal would be what is crossing the boundary between the red and blue regions.

You can press c (or click on the display apparent position button) to turn on the light delayed view. This represents what you could see if you were at the cross. You'll see a white/red/blue (depending on doppler shift) wire-frame objects in the top view, and some same-colored dots appear on the past light cone (bottom red-blue intersection).

One thing to note is that (while it is still paused) no matter what frame you change/accelerate to you are still seeing the same set of events.

The tau value displayed is what a clock on each of the objects would be displaying. If you un-pause it so -- say -- tau: 0s intersects with your light cone. Then re-pause it, you'll see that those events stay on your light cone. This is another way of saying 'you are seeing that event now' -- note that this definitely does not mean that this event happened now. Those would be the events that cross the horizontal white line and match the green wire-frame.

 

How long ago and how far away you see these depends on your position and matches what you seemed to be describing. Note that this is definitely not what we mean by now in relativity.

 

Also if you look at the light white lines that represent photons, they will never change angle (so they always go across the same amount for the same amount they go up, or have constant velocity). And this angle always matches your light cone.

Edited September 25, 2011 by Schrödinger's hat

[Iggy]

Iggy,

 

A calender on the wall of the spaceship would look exactly the same to the traveling twin on her way to Alpha Centuri, as it did when she took it off her brother's wall at home. According to me, she could still use it. According to SR, it wouldn't work.

 

I only meant that they are similar in the sense that neither accounted for the concept of 'now'. But, I don't think it is helping that SH and I are both explaining the same issue. I'll take the back seat while you consider his last post which was quite good.

[tar]

Schrödinger's hat,

 

I played with the link awhile. Not clear on the conventions, but there are a couple things I am having trouble translating into reality. One is the fact that the moving observer stays on the white present line. Fine in the sense that a second passes for both observers, so both are staying in the universal now's present, as events flow from top to bottom, but begs the question as to the existence of anything above the line, since it has not happened yet. And introduces my photon lag dilema in that in actuality as something moves away from me at a relativistic speed, it is getting farther away from my subjective now and I will not be able to witness its state 'til later. So while it may still exist similtaneously to me, from the God's eye view that is able to witness all current happenings at once, it is actually receding from me in time and if it where to reverse course and return to my location it would get closer to me in time and when it got back to my location, would again be in my now, and having never left the universe, nor the white x line, would be exactly as old as I am, regardless of the speed that it made the separation or the return.

 

I suppose the notion I can not shake, is more than a notion, it is a model of the world that I have been "building" for quite a while. Thinking things out. Taking into account my nature and history and connection with the universe, being both of and in it.

 

I am trying to understand the "meaning" behind language. That is the investigation I am on. And it involves science and philosophy, linguistics, neuroscience, sociology, psychology, religion, and well basically everything about the nature of humans, and our relationship to the world that there is to consider.

 

If we hold in our brains an analog representation of the universe, it is by definition, both correct and representative AND subject to limitation and error.

 

Analogies, maps, transforms, diagrams and such, where one thing stands for another, is very much what we do, considering the situation. An analogy can be perfectly internally consistent, and "work" perfectly well in our minds, but not completely describe the actual state of things, or "work" if we attempt to put it into practice and test it against the actual world.

 

As SwansonT points out. What we think does not determine reality. It is quite the other way around.

 

Now if people with quite obviously more grey matter than I have, have been working this situation, and come up with quite logical analogies and agreed upon what they mean, where they apply and how they help us predict and work with, and take advantage of the "way it is", I would say that we indeed have a certain handle on objective reality, and understand to a certain degree, "the thing as it is".

 

But when a paradox arises, it is not the world at fault. It is up to us to figure out where we are looking at it wrong, and carrying our analogy to far, or inappropriately.

 

Take the way the sky looks at night. Everything is "RIGHT HERE", "NOW". Stars look very small, but we have come to know they are huge and distant beyond comprehension. We see it immediately, but know it happened long ago. We know we are small and shortlived and mortal, but lay claim to it all, anyway, justly.

 

It remains important that we honestly assess when we are discussing the map, and when we are discussing the territory.

 

Regards, TAR2

[Schrödinger's hat]

Schrödinger's hat,

 

I played with the link awhile. Not clear on the conventions, but there are a couple things I am having trouble translating into reality. One is the fact that the moving observer stays on the white present line. Fine in the sense that a second passes for both observers, so both are staying in the universal now's present, as events flow from top to bottom, but begs the question as to the existence of anything above the line, since it has not happened yet. And introduces my photon lag dilema in that in actuality as something moves away from me at a relativistic speed, it is getting farther away from my subjective now and I will not be able to witness its state 'til later. So while it may still exist similtaneously to me, from the God's eye view that is able to witness all current happenings at once, it is actually receding from me in time and if it where to reverse course and return to my location it would get closer to me in time and when it got back to my location, would again be in my now, and having never left the universe, nor the white x line, would be exactly as old as I am, regardless of the speed that it made the separation or the return.

I don't quite understand what you're trying to say here. One thing that might help is distinguishing carefully between 'things' which are a series of events (the lines on that x/t diagram) and exist over time and events, which exist at a specific time.

Another distinction is between:

The white/red/blue stuff that appears when you turn apparent positions on. This represents what someone at the cross would see -- and events that ocurred in the past and,

The stuff represented by green lines/dots, this is only visible to our godlike being and represents what is happening in the now of the cross.

 

Also regarding stuff above the line. If we introduce concepts such as free will or (the traditional view of) non-determinism then things above the line certainly are distinct in their reality from things below the line (or at least things above the past-cone are distinct from those below it), but special relativity does not contain this distinction on its own.

Not only this, the bit below the white line or in the cone is different for each observer.

The usual way this is taught is to discuss this simplified map, and only later add these other features. Filling in detail, but being careful not to involve any contradictions.

 

If we hold in our brains an analog representation of the universe, it is by definition, both correct and representative AND subject to limitation and error.

 

Analogies, maps, transforms, diagrams and such, where one thing stands for another, is very much what we do, considering the situation. An analogy can be perfectly internally consistent, and "work" perfectly well in our minds, but not completely describe the actual state of things, or "work" if we attempt to put it into practice and test it against the actual world.

 

As SwansonT points out. What we think does not determine reality. It is quite the other way around.

 

Now if people with quite obviously more grey matter than I have, have been working this situation, and come up with quite logical analogies and agreed upon what they mean, where they apply and how they help us predict and work with, and take advantage of the "way it is", I would say that we indeed have a certain handle on objective reality, and understand to a certain degree, "the thing as it is".

 

But when a paradox arises, it is not the world at fault. It is up to us to figure out where we are looking at it wrong, and carrying our analogy to far, or inappropriately.

 

...

 

It remains important that we honestly assess when we are discussing the map, and when we are discussing the territory.

 

Unless I state otherwise, or perhaps such a time comes that we are all on the same page with regards to SR, you can usually¹ assume I am talking about the map. Physicists in my experience very rarely discuss the territory because anything our tiny little minds can have the slightest inkling of is almost definitely completely wrong.

The territory is more the domain of philosophy and ontology. This is where we should discuss what is not on the map, but any discussion must be consistent with the map where it says anything².

So you can't say something like 'only the bits below (or perhaps on) the white line exist'. Because different frames of reference have a different white lines, and without some reason to single out one frame of reference as special (a preferred frame -- note again that this isn't the preferred frame for some experiment, but for all observations and experiments everywhere) such a statement makes little sense.

 

¹When I say things like 'the universe is four-dimensional' this is a bit ambiguous. I very definitely mean that our measurements (in flat space) will be consistent with hyperbolic 4D geometry in the strictest mathematical sense -- barring any interpretation of what that might mean ontologically.

I also might mean that my philosophy considers time to be the same entity as space (but I don't know what type of thing that is) and that the cup beside past-me full of hot coffee 5 minutes ago has the same ontological status as the cup beside me now, half-full of cold coffee.

You are most welcome to dispute the latter if you have an internally consistent replacement (or even if you don't, I suppose), but the former would require you to have some experiment overturning relativity.

 

²This is not quite true, there is another map you can use, but it's somewhat hirsute and needs a jolly good shave.

Edited September 26, 2011 by Schrödinger's hat

[owl]

To my:

My objection to the relativity of simultaneity is also based on realism. Regardless of clocks and clocking all things everywhere are happening now, regardless of location or who sees what and when from different FORs. “Now” still means “the present.” Now IS the present. Location of events/objects does not dictate what “now” means, as relativity insists.

Cap 'n R asked:

"How do you know?"

 

How do I know that now is now regardless of location? If the lightspeed limit has nothing to do with the relativity of simultaneity, then distance doesn't matter and the present IS the present everywhere, one universal "now" rather than an infinite number of local "nows."

Even considering different FORs, I know that the past is no longer present and that the future is not yet present, so that leaves us with the reality that what IS happening now IS the present. How can this be wrong?

 

Here is my post (edited) 404 again (to save going through the last page). It could stand as my last post if no one will engage the philosophy of it or my thought experiment contrasting a real as is world with one dependent on frames of reference.

(I will finish with unfinished business with Schrodinger's hat. and a note on a witch hunt.))

This thread is appropriately in the philosophy section because it contrasts realism with idealism vis-a-vis relativity theory, specifically the concept that frame of reference, as in “there is no preferred...” determines “reality” in the same sense as subjective perception, with the difference that no actual person or subject need be present at any given frame of reference (FOR). My primary illustration of FOR as such a qualified “subject” in subjective idealism has been relativity’s claims about of length contraction.

 

Since thought experiments are well accepted in relativity theory, I proposed one in support of realism as debunking length contraction. I was told that length contraction is irrelevant to this thread's argument,....

that basically physics trumps philosophy here even in the philosophy section, so, therefore length contraction is irrelevant here because a physicist says so....

 

It is really very simple. If there were no intelligent life measuring things and the distances between them, would they still have an objective existence and intrinsic properties or not? An idealist will claim that reality depends on how it is perceived, while a realist will grant that “the world” in most general terms exists “as is” with or without perception and measurement of it from different FORs.

 

So, the realist will (and I did) disagree with the relativity theorists who claim that the shapes of things, for instance, depend on the FOR from which they are observed or measured. Cap ‘n R presented some thought experiments of his own to illustrate that a severely oblate spheroid describing the shape of Earth is just as valid as a nearly spherical Earth, because of length contraction as observed from an extremely high speed FOR, since “there is no preferred FOR." Another of his arguments was a metaphor of Earth as a statue seen from different angles (backside vs frontal view), like Earth as seen from the above extreme FOR.

 

Then we have the distances between objects in the cosmos, starting close to home with our solar system. A realist like me say that the distance between Earth and Sun, for instance, does not actually vary with the FOR from which it is observed, but only with Earth’s position in its elliptical orbit. I also say that Earth’s atmosphere does not actually vary in depth (distance through it) with the FOR of an incoming muon, for instance, an often cited argument for length contraction, as in “for a muon... it’s way less than the standard 200 or so miles.”

And, btw, all the above “realism” does not require that the speed of light be variable. My last thought experiment in that regard kept lightspeed constant even as the observers proceeded at 1/2 lightspeed with their lasers going ahead at ‘C.’ The velocity of light does not increase when fired ahead from a rocket going 1/2 lightspeed. Light can not be “pushed” faster than ‘C,’ and the one Au “track” hosting the experiment does not change lengths (contract) during the 5+ minutes each observer travels before seeing the other’s light.

 

Schrodinger's hat:

...relativity which posits that length contraction is a

phenomenon caused by measuring things without taking the time coordinate into account.

me:

So you are now saying that length contraction does not reflect an accurate measurement of objects or distances in "the real world" but rather an error of omission in calculation?

S.h.:

Similar, but without conflating measurement of objects and measurement of distances. Contracted length reflects an accurate measurement of distances, which are only an accurate representation of objects to the same degree angular size is.

 

So... again, still, whatever... how is a length contracted Earth diameter and a length contracted Au (or meter rod) "conflating" different concepts?

 

A final? note: I could reply to md65536's post 410 about 'that guy' with identical IQ scores to mine, who got banned from four forums; but, it would be way off topic, and it would require that I defend myself (why I got booted in each case, quite an interesting drama, really)) against the kind a witch hunt common in science forums when mainstream science is questioned or criticized.

 

(I have done my best to follow the rules here, and the forum has been better than average in tolerance* (aside from a few personal attacks) of my persistent criticisms, for which I thank you.)

* As in not banning me for my criticizing the mainstream.

 

How do you know?

 

 

No, it doesn't. Relative location has nothing to do with it. Where did you get that idea?

Sorry, I left out the timestamp and your second comment and question replying to my:

 

"Location of events/objects does not dictate what “now” means, as relativity insists."

"No", what doesn't...?

Relativity does not insist or agreeing that ""Location of events/objects does not dictate what “now” means...?"

 

If the present (now) does not depend on location ("here a now, there a now, everywhere another now, location specific") then what does the relativity of simultaneity mean?

Thanks.

[Schrödinger's hat]

So... again, still, whatever... how is a length contracted Earth diameter and a length contracted Au (or meter rod) "conflating" different concepts?

The difference is quite subtle. I could have two rods which are 1m long in a frame, one of them is moving at 0.866c in that frame, the other is still.

But if I switch to a frame where the first rod is still (according to SR) the formerly moving (now still) rod will now be 2m and the formerly still rod will be 0.5m. This is because the measure 'length' was not representitive of the true shape of the rod.

The rest length is a different concept, the rest length of one rod is and always will be 1m, and 2m for the other -- no matter the frame. Rest length is a similar concept to length, but it specifies a frame, ie. "The length in the frame where this object is still." For distances that aren't related to a single object, rest length is not defined.

 

A final? note: I could reply to md65536's post 410 about 'that guy' with identical IQ scores to mine, who got banned from four forums; but, it would be way off topic, and it would require that I defend myself (why I got booted in each case, quite an interesting drama, really)) against the kind a witch hunt common in science forums when mainstream science is questioned or criticized.

 

(I have done my best to follow the rules here, and the forum has been better than average in tolerance* (aside from a few personal attacks) of my persistent criticisms, for which I thank you.)

* As in not banning me for my criticizing the mainstream.

You are welcome to criticize science, but you have to do it in a scientific manner. If you are talking about philosophy of science, then your philosophy must be consistent with science. We have been trying to show you that (our reading of) your stated assumptions lead(s) to a contradiction.

 

Sorry, I left out the timestamp and your second comment and question replying to my:

 

"Location of events/objects does not dictate what "now" means, as relativity insists."

"No", what doesn't...?

Relativity does not insist or agreeing that ""Location of events/objects does not dictate what "now" means...?"

 

If the present (now) does not depend on location ("here a now, there a now, everywhere another now, location specific") then what does the relativity of simultaneity mean?

Thanks.

 

Things that have the same velocity as me, and are in my now share the same now as me no matter where they are. So do things that are at my here and share my now (regardless of their velocity). Things that are spatially distant and moving at a different velocity do not share my now.

 

If you could please respond to my diagram and outline of the jousters situation, I will show you the logic that leads to this conclusion from stated assumptions (which you will be welcome to challenge as they are stated).

Edited September 27, 2011 by Schrödinger's hat

[Cap'n Refsmmat]

How do I know that now is now regardless of location? If the lightspeed limit has nothing to do with the relativity of simultaneity,

But it does!

 

then distance doesn't matter and the present IS the present everywhere, one universal "now" rather than an infinite number of local "nows."

...although distance doesn't matter.

[owl]

Backing up for background clarity before addressing more recent posts, tomorrow (just another quickie):

Schrodinger’s hat:

 

Things that are spatially distant and moving at a

different velocity do not share my now.

 

I hope that you realize that this is a philosophical position you are *assuming.* (I know... based on the doctrine of relativity of simultaneity... the "teaching", as it were.)

 

So if you can not see their now, it isn’t happening now. Is that what you mean?

Would you mean that a solar flair is not now happening because we can not now see it? We will see it in a bit over 8 minutes, but that is 8 minutes from now-there-and-now-here,... same now.

[Cap'n Refsmmat]

So if you can not see their now, it isn’t happening now. Is that what you mean?

Would you mean that a solar flair is not now happening because we can not now see it? We will see it in a bit over 8 minutes, but that is 8 minutes from now-there-and-now-here,... same now.

Relativity of simultaneity has nothing to do with signal delay, or the time it takes for us to see something simply because it takes light a while to reach us.

[Schrödinger's hat]

I hope that you realize that this is a philosophical position you are *assuming.* (I know... based on the doctrine of relativity of simultaneity... the "teaching", as it were.)

 

So if you can not see their now, it isn't happening now. Is that what you mean?

Would you mean that a solar flair is not now happening because we can not now see it? We will see it in a bit over 8 minutes, but that is 8 minutes from now-there-and-now-here,... same now.

 

No this is a simple scientific statment. The definition of now I am using is simply a class of coordinates, it has the same ontological status as a line of longitude, or an altitude. Sadly I have no word for this concept which is distinct from the philosophical entity 'now' (whether we be talking about presentism or some extension of relativity to include the concept). We can discuss philosophy of science only once we agree on the science.

I did not state 'according to the model of relativity' in that sentence because I thought it was clear from the context.

 

At any rate, you're still conflating light delay and the simultenaety of relativity. These are distinct concepts.

Let's say I'm sitting here, typing on my computer, and there is a solar flare happening now, so I'll see it in eight minutes.

There's also an alien surfing the solar flare in its version of extreme sports, moving at a high fraction of c.

 

For the sake of this argument ignore the motion of earth relative to the sun, any contribution from this is insignificant.

According to relativity:

To me, the solar flare, the surfing, and the typing are happening now.

To some laboritory on the sun which is not moving relative to the sun, the solar flare, the surfing and the typing are happening now.

To the surfer, the solar flare is happening now, but the typing is not.

 

Note that the sun-lab and I measure the same now (everywhere in space) because we are not moving relative to one another.

The surfing and the solar flare always happen at the same time because they are in the same place.

But the surfer measures a different now to me.

 

This is a direct logical consequence of all observers measuring a constant speed of light.

It is quite possible to argue that all but some special set of observers are mistaken in what they measure as 'now', but:

If all observers measure all light to be moving at 3*10^8m/s relative to them, then they MUST measure different sets of events to be happening at the same time if they move at different velocities.

Exactly how this measurement is reflective of reality is open to philosophical discussion.

Whether or not this measurement will be made is not, and would not be even if there were a preferred frame of reference or special relativity were wrong in a number of other ways.

 

If this is not obvious to you (and it is not obvious to most, I would possibly even say all, people), then respond to my post about the jousters and I will endeavour to show you why.

Edited September 27, 2011 by Schrödinger's hat

[Iggy]

Location of events/objects does not dictate what “now” means, as relativity insists.

So if you can not see their now, it isn’t happening now. Is that what you mean?

Would you mean that a solar flair is not now happening because we can not now see it? We will see it in a bit over 8 minutes, but that is 8 minutes from now-there-and-now-here,... same now.

 

Did you forget the following straightforward statements? And, whether you have forgotten or not, how many times more should they be repeated, and by how many people, for you to get rid of the strawman?

 

The non-simultaneity does not come from signal delay

Relativity of simultaneity has nothing to do with signal delay, or the time it takes for us to see something simply because it takes light a while to reach us.

Signal delay, or "photon lag" is not the cause of the relative nature of simultaneity.

Ignore signal delay. We're not talking about signal delay

Where did you get the idea that the time lag for information about events is what causes relativity of simultaneity, or even has anything to do with it at all?

You are still conflating light delay (the time it takes for us to see things) with relativity of simultaneity. The eight-minute delay in the travel of light from the Sun to the Earth has absolutely nothing to do with relativity of simultaneity as presented in special relativity.

I don't think you understand; signal delay -- the delay in "seeing the happening" -- is not relevant to my example.

 

moving to your recent and relevant question...

 

If the present (now) does not depend on location ("here a now, there a now, everywhere another now, location specific") then what does the relativity of simultaneity mean?

 

It means "relative to velocity". That's always what it means.

 

Time is relative to velocity. Distance is relative to velocity. Simultaneity is relative to velocity. There is a difference between "location" and "velocity". Even if you like the former and can't be bothered getting corrected on it, the latter is correct.

 

The difference between one frame of reference and another frame is velocity so when someone says "length depends on frame of reference" they are saying that the length between two things as it exists at one constant velocity (regardless of location) is different from the length between the same two things as it exists at another (relatively different) constant velocity.

 

The order of events anywhere in one frame is different from the order anywhere in another frame. Location, signal delay, and 'photon lag' is irrelevant.

 

This is why when you say "the sun-earth distance does not depend on the location from which it is viewed", the whole thread shakes their head and clinches their teeth.

 

Please realize that you aren't disagreeing with relativity -- you are presenting a strawman based entirely on your lack of knowledge of how relativity works. You are not alone in this confusion between location and velocity. You may well be alone, however, in your inability to be corrected on the misconception despite so many people telling you so many times that it is wrong and a misconception.

 

The trick you could try is to remember things from yesterday. There are enough statements correcting you that I quoted up there that you would be forced to abandon the misconception if only you could remember the statements. Just try remembering what people say -- even if they say it as much as a day ago.

Edited September 27, 2011 by Iggy

[owl]

Still begging for clarification of relativity of simultaneity as in how it can logically contradict presentism.

 

“Even considering different FORs, I know that the past is no longer present and that the future is not yet present, so that leaves us with the reality that what IS happening now IS the present. How can this be wrong?”

 

Since simultaneity means happening at the same time, on what basis does relativity’s lack of simultaneity (or “relativity of simultaneity”) deny/contradict the above?

Repeating that it doesn’t depend on light delay doesn’t answer the question.

 

This thread is on the philosophy of science, particularly relativity’s claims about frames of reference determining reality, or FORs as a qualified* subjective criteria for “reality” as a form of subjective idealism. *(No person or subject required to establish an abstract FOR, reality depends on FOR,... how you look at it.)

 

Here again is a summary of the above summary post:

An idealist will claim that reality depends on how it is perceived, while a realist will grant that “the world” in most general terms exists “as is” with or without perception and measurement of it from different FORs.

 

(My post 404)

...could stand as my last post if no one will engage the philosophy of it or my thought experiment contrasting a real as is world with one dependent on frames of reference.

See again the bolded portions of post 418, still not addressed.

 

Schrodinger’s hat:

You are welcome to criticize science, but you have to do it in a scientific manner. If you are talking about philosophy of science, then your philosophy must be consistent with science. We have been trying to show you that (our reading of) your stated assumptions lead(s) to a contradiction.

 

This thread poses a philosophical challenge to some of relativity’s most absurd assertions based on the theory of length contraction.... specifically, that Earth’s diameter, depth of atmosphere, distance from the Sun, and the actual length of a solid meter rod all depend on the frame of reference from which they are observed and measured.

 

See all versions of realism’s rebuttal above. Philosophy of science is appropriately presented in a philosophical “manner”, as above. We need not start with the “scientific” dictum “there are no preferred frames of reference” from which to describe “reality.” The "world" (let's stay concrete and say Earth) already had a reality of its own (and distance from the sun, varying only a bit in its orbit) before life evolved here, much less intelligent life with nimble minds, clocks, and measuring rods. You still have not acknowledged this fact, upon which realism is based.

Reality does not depend on frames of reference from which it is observed. So science must investigate “reality” and all of its intrinsic properties from the most reasonable frame of reference possible for each object of investigation, be it objects themselves or the distances between them in the real world.

 

Again, you say, “Things that are spatially distant and moving at a different velocity do not share my now.”

You (and the relativity of simultaneity in general) claim that there are different, spatially separate “nows” as if the claim itself debunks presentism’s claim that the present IS everywhere now, regardless of the space between locations. And the Cap ‘n repeats that it (relativity of simultaneity) is not about light delay between FORs, not about the distance between them. Which version is it?

You say:

If you could please respond to my diagram and outline of the jousters situation, I will show you the logic that leads to this conclusion from stated assumptions (which you will be welcome to challenge as they are stated).

 

There is no point in that if you continue to *assume* the primacy of frames of reference for describing reality in direct contradiction to my above arguments.

However, if you will “please” reply as above repeatedly requested, then I will again go ‘back to the drawing board’ with you.