12 replies to this topic

[Mark]

The other month I had a question buzzing around in my head, so I'll pose it, and see what you guys think.

its a bit of a warp on the twin paradox.

Imagine Bill and Ben, two twins on earth.
of these two twins one of them (Bill) travels to the moon at near luminal speed.
now according to Special Relativity (SR) time slows for the traveling twin, so that when the two twins meet back on Earth the traveled one is younger.

Now, whether or not you're an A-Theorist or B-Theorist we can both happily agree that every person suffers the appearance of experiencing a present moment that advances in time (that is whether or not the 'present' or its advancement is real).

NOTE:
A-Theory (aka. 'Tensed theory of time') implies believing that the present is Real and privileged over other moments of time
B-Theory (aka. 'Tenseless theory of time') implies believing that the present isn't privileged

let us call the rate at which our 'present moment' does (or does appear) to advance the 'rate of appreciation of time' or just the 'appreciation'.

so lets have Bill experiencing (or suffering the appearance of experience) of his 'present moment' at his rate of appreciation, and Ben the same for his 'present moment' and his rate of appreciation.

now intuition should tell us that before they leave their 'present moments' will coincide (that is that Bill will experience the same moment as Ben) and that their rates of appreciation will be the same (they will continue to experience the same moment).

however when Bill sets off from Earth, SR will tell us that every one of Bills physical processes will slow down relative to Ben's.

Note in all of this I assume that Earth is the reference frame.

there are 3 possibilities:

1. Bill and Ben's moments advance at the same rate
(Ben's appreciation = Bill's appreciation)

2. Bill's moment will advance slower than Ben's
(Bill's appreciation < Ben's)

3. Bill's moment will advance faster than Ben's
(Bill's appreciation > Ben's)

Here is an illustration (although it is a slightly skewed representation)



now here is what I think can be said for all 3 possibilities:

1. if Bill and Ben's moments advance at the same rate, then when they meet back on earth they will again be experiencing the same moment together (which is what most of us want), yet there is a slight absurdity in believing that every physical process literally slows down its rate of progression with speed, yet the rate of our appreciation of time should not.

Also, if we try to imagine it (if Bill were 99.999% of c), we would have to imagine Bill waiting for his nervous system to respond to his wishes - because every process would slow down around him.

2. this seems to be the most natural position if one wants to be a Materialist about the Mind, if all of the Bodies processes literally slow then so would every Mental process.
This however would make Bill and Ben's experience different moments when they return back to earth.

but if we try to imagine it we would have to imagine Bill getting Even more bored than in our imagined scenario in 1.
because every physical process would be slowed around him and his appreciation of then would also be slowed.
this would give the appearance that the things around him were twice slowed.

3. if time advances faster for Bill, then he would remember his experience as if it took a short time (which may be common to all possibilities) and would have experienced it as if it did indeed take a short time (uncommon).

in this case our scenario could have Bill experiencing the physical things around him just as if he were stationary.
This is kind of what you'd expect in any Relativity. (ie. that you cant tell the difference about whether you're moving or not)
In this case all the processes around him would slow down but his rate of appreciating them would speed up to compensate.

this one would also have Bill and Ben experience different moments when they return to earth.

Yet this one is the strangest options, as every Bodily process would slow down, yet the mental process would speed up!


I think that these are the possibilities if one is willing to acknowledge the appearance of experiencing a present moment which advances. (which I suppose is possible to deny!..)
I particularly want this question to be independent of whether or not we believe in A-Theory or in B-Theory.

note however that if we accept either of 2 or 3, then we must concede (with near certainty) that no one of us is experiencing the same moment - for each one of us has traveled at a different net speed throughout their time than the rest; This is VERY counter intuitive!

yet on the other hand if we accept 1, then I think we may have well have sunk a major objection against A-Theory from SR.
thus we should probably be A-Theorists, especially since most of us will acknowledge its intuitive value.

Yet believing a process that proceeds at the same rate regardless of reference frame and velocity seems to fly right into the face of SR itself!


The question that I want to pose is what to do with this kind of dilemma.

Its big and long, and yes SR screws with everyone's head i think - so perhaps I'm missing something.

what do you think.

Edited by Mark, 12 January 2010 - 07:38 AM.

[Steel Samurai]

As far as I can tell what you're asking about is the perception of time, i.e. whether bill, during his lunar journey, is actually conscious of a change in the rate his body experiences time. One part of the question, at least, can be answered simply. When Bill returns to earth he will no longer be traveling at a faster rate than Ben, and thus the temporal effects of special relativity will be null. Ben will be older, but he and Bill will be sharing the same moment again, if indeed they were sharing it to begin with. As to Bill's perception during his actual journey, I am of the opinion that both his perception of time and his physical processes would be altered so that time would be experienced just as on earth. i.e. if a mechanical clock was on board his ship, the tick of a second would seem as though it took the same time on earth. Should an observer from earth be able to see the same clock, however, the tick of a second would take much longer than the same clock if watched on earth.

[Mark]

As far as I can tell what you're asking about is the perception of time, i.e. whether bill, during his lunar journey, is actually conscious of a change in the rate his body experiences time. One part of the question, at least, can be answered simply. When Bill returns to earth he will no longer be traveling at a faster rate than Ben, and thus the temporal effects of special relativity will be null. Ben will be older, but he and Bill will be sharing the same moment again, if indeed they were sharing it to begin with. As to Bill's perception during his actual journey, I am of the opinion that both his perception of time and his physical processes would be altered so that time would be experienced just as on earth. i.e. if a mechanical clock was on board his ship, the tick of a second would seem as though it took the same time on earth. Should an observer from earth be able to see the same clock, however, the tick of a second would take much longer than the same clock if watched on earth.

Good answer, but not sure it works.
you've said:

"Ben will be older, but he and Bill will be sharing the same moment again, if indeed they were sharing it to begin with."

so your saying that the 'net present Moment shift' between the two throughout their journey will be zero. (bad way of putting it, I know)

you've also said:

"I am of the opinion that both his perception of time and his physical processes would be altered so that time would be experienced just as on earth. i.e. if a mechanical clock was on board his ship, the tick of a second would seem as though it took the same time on earth."

So if I understand you, your saying that although the clock actually slows down (relative to earth), his experience of the slowed clock must correspondingly speed up (relative to earth), such that there is no experiential difference for him.

yet if his experience actually has been sped up throughout his whole journey (relative to the observer on earth), surely when he comes back to earth he will have experienced more time than the twin who stayed on Earth.
And so the 'net Moment shift' will not be Zero.

[arunma]

Hi Mark. This is a most interesting topic you've brought up. Just the thing to breathe some new life into the Science forum!

First, I think we need a better definition of appreciation of time. I detect a possible underlying fallacy here (but correct me if I'm misunderstanding). The fallacy is that the question assumes that time somehow transcends the reference frame. One of the philosophical implications of SR is that time is not absolute. Someone's "appreciation of time" depends entirely on the reference frame in question. Note that in SR, the idea of absolute simultaneity is lost. No two events can be absolutely simultaneous. Two events that are simultaneous in one reference frame will not be simultaneous in another frame.

Second, there seems to be an assumption here that the human brain is somehow special in terms of perception of time. But it isn't. Like everything else, it operates via physical processes, and these processes take time. So Bill will appreciate every second on his spaceship in the same way that Ben does on earth. The only difference is that when the twins reunite, Bill will have appreciated fewer seconds than Ben.

What we need here is a mathematical definition of appreciation of time. Is it simply the derivative of the transformed time with respect to the untransformed time? If so, this is simply the reciprocal of the relativistic gamma factor. But we can't go much further than this, because the transformed time and untransformed time are the only times that there are. There's no absolute time that these two times can be compared to, and this is something that must be kept in mind when considering the philosophy of time in SR.

[Mark]

Arunma, very awesome and essential questions.

I think it may be easier if try to answer your questions in reverse order.

Point 3
"What we need here is a mathematical definition of appreciation of time. Is it simply the derivative of the transformed time with respect to the untransformed time?"

OK, I wrote a lot of interesting stuff here, but I found that I sort of half answered it myself in the next part.
feel free to skip all of the stuck-through stuff. (*smacks self in head*)

I think its good stuff especially if you need clarification about what this 'appreciation' business is anyway. but hey.
if you want to read it, simply highlighting the text makes it clearer, or you could copy it into notepad to get rid of the lines completely. your choice

Ok, I'm not sure if there can be much of one. I'll try to explain why.

If I have a description of my height in terms of my age,
say: Height = 80cm * (1 - e^(-1 * Years_old / 10)).
and that: Years_old = time - time_of_birth

This mathematical description doesn't answer the question of how high I am now. right?

now equally so, if I know the space-time positions of every event in the universe, it still will not answer the question of how high I am now.

To answer the question "how high am I now?" we need to define 'now'
ie. something like: 'it is now' => 'time=2010.0489...'

what is 'now'?
This is one of the bigger differences between A and B theory, is that the A theorist believes that a privileged moment - 'now' - is real and advances in time, whereas the B theorist denies this.

The A-theorist's world view features things that 'come to be', things that 'are', and things that 'cease to be'. (or at least 'come', 'are', and 'cease' to be in the 'now')
whereas B-theory will only acknowledge things that 'are'

notice that the B-theorist's worldview feels totally 'static' where the A-theorist's isn't.

The A-theorist believes in an essential difference between the past and the future - the set of things in the past are the things that have happened, and the set of things in the future are the things that will happen.

however the B-theorist doesn't believe in any difference - ie. the set of things in the 'future' are events that occur at a time later than when the referring sentence was uttered, and the 'past' are the set of events that occur at a earlier time.

So a B-theorist will read the question "Is it 3:00 Now?" as "Is this sentence uttered at 3:00?"

Thus I've heard people use the process of entropy as the defining difference between a greater and lesser time index and thus between the future and past.

eg. the A-theorist will say: "the cat WAS on the mat" where the B-theorist will say "the cat is on the mat on the 12th Jan 2010 but not on the 13th"


Now, in any Mathematical discourse, you simply declare things that 'are', ie. the static facts. eg. '1+1=2', 'a = b', 't=2010', 'dx/dt=5'
notice however that you NEVER declare the 'coming to be' of anything.

all that is ment by 'x=t' is that 'if t=5 then x=5', and 'if t=50 then x=50' etc.
and all that is ment by 'dx/dt=5' is that 'x=5t+C' and wah-la, another static fact.
and again, all that is ment by 'df(2)/dx=3' is a static fact about a relation between two infinitely close points on f(x) about x=2.

in this way the essential feature of A-theory will be missing from any total mathematical description of time

OK, the 'appreciation of time', is the rate at which things 'come to be', the rate at which 'now' advances, or 'the rate at which the seconds tick by'.

I don't have anything against the possibility of 'the appreciation of time' either increasing or decreasing.
imagine if suddenly the seconds literally began to tick by twice as fast. and why not?
(try to describe that mathematically! - "time passes at 2 seconds per second..." => dt/dt=2 )

now B-theory seems to be in vogue at the moment, so here's the disclaimer, even if 'now' dosnt exist, and even if 'the rate at which now advances' is total bosh, we (i think) still agree that it appears that we occupy a moment, and it appears as if it changes (even if a total illusion) so all we need to do is work with the the illusory moment, and its illusory change.

it seems that the 'appreciation of time' would have to be some kind of variable.
I cant see any reason to think that the 'appreciation of time' must be the same for everyone, and no reason to think that everybody must have a coinciding 'now' moment.

So my question sets up Bill and Ben, and assigns each the same 'now' moment and each a rate of 'appreciation' and then asks what happens when Bill hits 99.999% of c.

I don't think that the 'appreciation of time' has any necessary relationship between transformed or untransformed time.
all of these concepts could work just as well for a 3+1D space time as it does for relativistic space time.

Phew. ok, next point.

Point 2:
"here seems to be an assumption here that the human brain is somehow special in terms of perception of time. But it isn't. Like everything else, it operates via physical processes, and these processes take time. So Bill will appreciate every second on his spaceship in the same way that Ben does on earth. The only difference is that when the twins reunite, Bill will have appreciated fewer seconds than Ben."

I think previous rant about 'appreciation' above should clear this up.
but lets imagine another scenario to get the feel.

Bill and Ben stay on earth (nothing relativistic) and Bill has a shot of 'NeuroStimulant' that makes his brain immediately go twice as fast, and makes his 'appreciation' immediately double that of Ben's.
this is to say that Bill will literally experience time passing twice as fast as Ben.
and lets imagine that they share the same moment before Bill takes the shot at time 0.

now when Bill experiences time 1s, Ben will be experiencing time 0.5s.
and when Ben is experiencing time 1s, Bill will be experiencing time 2s.
alas, their present moments no longer coincide.
note that all this can happen even if they share the same clock on Earth and there is no SR involved.

MATH

perhaps we could have a unit of 'Experiential Time' T, and experienced times t1 (Bill's) and t2 (Ben's).
thus:

dt1/dT = 2 * dt2/dT (Bill's time passes twice as quickly as Ben's)
=> t1 = 2 * t2 + C
if t1 = 0 then t2 = 0 thus C = 0
=> t1 = 2 * t2
if t2=1s then t1=2s

therefore if Ben is experiencing second 1, Bill will be experiencing second 2.

END MATH

Now I suppose the invention may seem a bit ridiculous, but is the result and what it codifies reasonable?

Does this situation seem plausible if we allow the possibility of such a NeuroStimulant?

infact the the original twin paradoxish situation is very much like this, except with the relativistic spanner.

Most people (i think) would simply deny the possibility of such a NeuroStimulant, and say that everyone's appreciation is allays the same and equal with everyone else's, but if you follow my twin paradoxish thingo, then that would lead you to odd conclusions. - about Bill waiting for his body to respond etc.

I hope you can see that in our twin experiment its hardly just simply a question about how much they've aged when they reunite, or about the seconds of time difference between their two clocks at any point in time, or about the number of seconds on anyone's clock, on earth, in a spaceship, or otherwise.

Do our twins experience the same moment when they return? Do their 'appreciation' rates change when their brains slow down? - or not?


Point 1:

"The fallacy is that the question assumes that time somehow transcends the reference frame. One of the philosophical implications of SR is that time is not absolute. Someone's "appreciation of time" depends entirely on the reference frame in question. Note that in SR, the idea of absolute simultaneity is lost. No two events can be absolutely simultaneous. Two events that are simultaneous in one reference frame will not be simultaneous in another frame."

No hassles with the simultaneity.
As far as i understand it, any inertial reference frame is equally valid, and thus the choice is arbitrary.
so for my twin quizzer, I'm under the impression that I've taken the earths reference frame.
basically I think I've asked "does Bill's appreciation of time speedup, slowdown, or stay constant with respect to earth seconds? (taking the earth as the reference frame)"



This kind of thing feels more like philosophy+physics than strait physics+math. but I still think its probably good to have a handle on how to imagine SR and to ask what it would be like to be Bill.


Dang good questions Arunma, sorry it took so much writing to answer; good questions can be like that.

Edited by Mark, 13 January 2010 - 08:11 AM.

[Showsni]

I think, when the travelling twin gets back, he'll be experiencing the same moment, but calling it something different.

Let's say they count out loud how many moments they've experienced. Whilst Bill is travelling, time slows down; so you get the following:

(On earth, before take off)
Ben Bill
0 0
1 1
(launches ship; let's say Bill's time is half as much as Ben's)
2 (1.5)
3 2
4 (2.5)
5 3
(returns to earth)
6 4
7 5

The "present time" on earth is still the same; but Ben thinks it's moment 7 and Bill thinks it's moment 5. As far as Bill's concerned his trip only took 2 moments, though from Ben's point of view it took 4 moments. Since all time on Bill's spaceship is slowed down, his brain is slowed down exacrlt as much as everything around him; so time just appears to be passing at the normal speed.

Bill and Ben stay on earth (nothing relativistic) and Bill has a shot of 'NeuroStimulant' that makes his brain immediately go twice as fast, and makes his 'appreciation' immediately double that of Ben's.
this is to say that Bill will literally experience time passing twice as fast as Ben.
and lets imagine that they share the same moment before Bill takes the shot at time 0.

now when Bill experiences time 1s, Ben will be experiencing time 0.5s.
and when Ben is experiencing time 1s, Bill will be experiencing time 2s.
alas, their present moments no longer coincide.

If it doubles the speed of his brain then he'll observe time as going half as fast as usual; you should really give it to the other twin to match the above plan... But, yes, you'll get:

Bill Ben
0 0
1 1
(Bill quaffs drink)
2 (1.5)
3 2
4 (3.5)
5 3
(effects wear off)
6 4
7 5

Again, they're still experiencing the same moment, they're just calling it something different. As above, one of the twin notices two moments that the other twin doesn't notice at all.

[Mark]

Right

So lets see if I understand your walk through of the situation.

you've given the following:

Bill Ben
0 0
1 1
(Bill quaffs drink)
2 (1.5)
3 2
4 (3.5)
5 3
(effects wear off)
6 4
7 5

now, I understand what you mean by this is: when Bill remembers experiencing 3 seconds of time he will yell out '3', at this point Ben will have remembered experiencing 2 seconds of time and he will respond '2' etc.
So that when the effect of the drink wears off, then they will still be experiencing the same moment together but they will remember the passed time as if it took different durations.

please correct me if I'm wrong.

It seems that your analysis of the situation assumes that both twins have a single 'now' moment that advances at a constant rate. but that one twin will remember the past time as if it were shorter.
eg. so when Bill experiences the shouting out of '3', Ben will be experiencing what Bill calls 'second 3' even though he will think it is 'second 2' and when Bill experiences the shouting of '6' Ben will be experiencing the moment that Bill thinks is 'second 6'.
in this way their present 'now' moments always coincide.

This seems to be a pretty good answer if you believe that everyone must continuously share a 'now' moment, but I think it ducks the crux of the question.

In the drinking experiment I've assumed the existence of the 'NeuroStimulant' that:

makes his 'appreciation' immediately double that of Ben's.
this is to say that Bill will literally experience time passing twice as fast as Ben.

and then I've asked whether or not it follows that their present moments will split.

notice that i haven't said:

this is to say that Bill will literally remember time as if it were passing twice as fast as Ben.

now I gather that most people will feel that this kind of 'Neurostimulant' is unrealistic, but unless there is any kind of logical inconsistency in positing such a thing then I don't see why I should refrain from it.


Ok, here is why it matters.

if in our twin experiment (the one with Relativity) both our twins continuously share the same 'now' moment, and this 'now' moment changes at a constant rate.
If our twins experience this 'now' moment and its change, then it follows that Both Bill and Ben will experience Earth seconds as if they were Earth seconds regardless of whether or not one of them was traveling at 99.999% of c.
in this case the clock on board the ship traveling will have slowed relative to earth seconds, and if Bill (the traveler) experiences Earth seconds as if they were Earth seconds, then he should experience the slowing of his own clock. (this is regardless of how he remembers anything)
and if his clock slows, then so too must his body, and its processes, and so we are left with a Bill experiencing himself in slo-mo.

Edited by Mark, 15 January 2010 - 07:59 PM.

[arunma]

Mark, I think I understand what you mean by "appreciation of time." Ultimately, as evidenced by the evoking of the neurostimulant, this depends on the human consciousness. Effectively it depends on the processing power of the brain. Would you object to renaming the "appreciation of time" with another quantity, such as the "clock speed" of the brain?

[Mark]

Mark, I think I understand what you mean by "appreciation of time." Ultimately, as evidenced by the evoking of the neurostimulant, this depends on the human consciousness. Effectively it depends on the processing power of the brain. Would you object to renaming the "appreciation of time" with another quantity, such as the "clock speed" of the brain?

would this help?

I suppose we could name it whatever we wanted.

just that I'm not sure it does depend on the processing power of the brain.
suppose every one of the neurons in my head sped up their operation, I don't think it necessarily follows that time would pass faster for me.

but Ok, I accept... "Clock speed"... done.

As of now on:

"Clock speed" := rate that at which a person's present moment changes.

and I will assume:

Arunma's Thesis: Clock speed is proportional to the processing speed of the brain.

do you accept?

Edited by Mark, 16 January 2010 - 03:57 AM.

[Showsni]

if in our twin experiment (the one with Relativity) both our twins continuously share the same 'now' moment, and this 'now' moment changes at a constant rate.
If our twins experience this 'now' moment and its change, then it follows that Both Bill and Ben will experience Earth seconds as if they were Earth seconds regardless of whether or not one of them was traveling at 99.999% of c.
in this case the clock on board the ship traveling will have slowed relative to earth seconds, and if Bill (the traveler) experiences Earth seconds as if they were Earth seconds, then he should experience the slowing of his own clock. (this is regardless of how he remembers anything)
and if his clock slows, then so too must his body, and its processes, and so we are left with a Bill experiencing himself in slo-mo.

As far as Bill's concerned, everything will seem normal; that's because his body, brain, etc. will slow down exactly as much as his clock does.

We're assuming that each person experiences everything in a series of moments. That's the same as a television displaying 24 frames in a second; each person's eye/brain is only fast enough to pick up 24 frames per second, so each single frame is similar to a single moment of time. Then the neurostimulant has the effect of doubling the number of frames per second your eye can pick up; instead of seeing 24 per second, you're now watching 48. However, your brain doesn't know it's working faster; it just assumes that 24 frames = 1 second. So when 1 second of real time passes, you see 48 frames, your brain assumes 2 seconds have passed and the net result is everything appearing to be half as fast as it used to (taking 2 seconds to show what used to show in 1 second). With the relativity, your brain is slowed; so it can now only pick up 12 frames per second. However, the speed the frames are fed by is also slowed; a second's worth of footage will take two seconds to show, so you'll only get 12 frames per second. Then your brain will pick up 24 frames in 2 seconds, and assume it's taken 1 second; so everything will appear to be going at the normal speed, even though it's actually taking twice as long.

[Mark]

Showsni,

that's a really good way to illustrate stuff! - mind if I borrow your technique?

Alright I think we need to separate some very different notions: the rate at which time SEEMS to pass, the rate at which time ACTUALLY does pass, and the rate at which time will have SEEMED to have passed.

so for instance, if I say that "1 hour talking to a beautiful blond takes 5 minutes", I mean to say that 1 hour will have SEEMED to have taken 5 minutes (in my memory), but certainly not that Time itself ACTUALLY has sped up or that the experience itself actually went more quickly (SEEMS).

so a quick question about your last post:
If today (on earth) my 'frame rate' slows from 24 to 12, does that mean that time SEEMS, will have SEEMED or will ACTUALLY pass half/twice as fast?

because of this question I'm not sure how to interpret what you last said, however here is an analogy of how I interpret what you've said, correct me If I'm wrong:

Imagine there is a VCR playing a movie tape named 'events in time', and this tape plays and is recorded at, a billion frames per second.
Imagine there is a TV called 'bill's awareness' that is connected to this VCR, and it plays what the VCR outputs at a much lesser frame rate - of 24 frames per second.
and then imagine there is a computer (called 'Bill's memory') connected to the TV that sequentially captures every frame displayed on the TV, and names each new image "second 1", "second 2", "second 3" etc.

so that the rate the movie is playing in the VCR = rate at which time ACTUALLY passes
the rate at which the movie is displayed on the TV = rate at which time SEEMS to pass
and the images on the computer form the rate at which time will have SEEMED to have passed.

so ordinarily, the film plays, and the TV actively displays the point where the movie is upto (thus rate SEEMS = rate ACTUAL), the TV displays 24 of these frames per second, and each of those frames gets stored and labeled accurately on the computer (thus rate SEEMED = rate SEEMS = rate ACTUAL).

lets imagine that Bill has a VCR, TV and computer, and that Ben has his VCR, TV and computer, and lets imagine that both VCRs play identical copies of the same tape: 'events in time'.

now if the frame rate of Bill's TV doubles (to 48 fps), his TV will still accurately display the point where the movie is upto (Bill's rate SEEMS = Bill's rate ACTUAL), but the rate at which new images get loaded onto his computer increases, and as each is labeled 'second 1', 'second 2' etc, it will have SEEMED as if time were passing half as fast (rate SEEMED = 0.5 * rate SEEMS) and any duration will have SEEMED to have taken twice as long.

In this same way, your saying that when when Bill takes Neurostimulant his 'framerate' will double, and thus he will remember his time on the stimulant as if it were twice as long.
now if both Bill's and Ben's setup is identical before Bill takes the stimulant, then it follows that at no point do Bill's TV and Ben's TV display different points in the movie, because the framerate has nothing to do with it.
and since what is on their TV is what they are currently experiencing, then their time SEEMS to be passing at the same rate for both of them.
The only net result is that Bill will remember his time differently, it will have SEEMED to him differently.

If I understand you correctly then your answer seems like a good answer, it is coherent, and it preserves a universal present moment (everyone's TV displays the same point in the movie - regardless of framerate)

however the question that I wanted to pose by introducing the Neurostimulant experiment was this:
"Given that the Neurostimulant makes Bill's VCR speed up! (NOT his framerate) does it then follow that Bill and Ben will SEEM to experience different moments?"

(the answer I think is Yes, providing the TV is directly connected to the VCR)

it was the speed of the VCR that I was getting at by 'the appreciation of time' (which I assumed to be the speed at which the movie is played on the TV) - the rate at which time SEEMS to pass in their experience.

My origional question can be rephrased like this: "if Bill goes on his trip, will the rate the movie plays on his TV slow down, stay at constant speed or speed up?"

your answer seems to be that it will: stay at constant speed.

Now, if your right, if everyone SEEMS to experience the same moment continuously (regardless of how it will SEEMED to be) and if Bill is in space and everything slows around him, then to Bill it will SEEMS to be that everything is slowed, even if it wont SEEMED to have been that way.

(whopping bad grammar! - but if you understand me then thats enough)

Man, how do I write so much.

Edited by Mark, 17 January 2010 - 11:32 PM.

[arunma]

Sorry Mark, I've neglected this thread for 11 days! I was busy doing real physics research, which sadly isn't nearly as fun as these physics questions that screw with your brain.

Mark, I think I understand what you mean by "appreciation of time." Ultimately, as evidenced by the evoking of the neurostimulant, this depends on the human consciousness. Effectively it depends on the processing power of the brain. Would you object to renaming the "appreciation of time" with another quantity, such as the "clock speed" of the brain?

would this help?

I suppose we could name it whatever we wanted.

just that I'm not sure it does depend on the processing power of the brain.
suppose every one of the neurons in my head sped up their operation, I don't think it necessarily follows that time would pass faster for me.

but Ok, I accept... "Clock speed"... done.

As of now on:

"Clock speed" := rate that at which a person's present moment changes.

and I will assume:

Arunma's Thesis: Clock speed is proportional to the processing speed of the brain.

do you accept?

Hmm...I don't really know. But yes, let's accept that a person's present moment changes proportionately with the processing speed of the brain, and see where that leads us. This should be interesting!

[Mark]

Yeah, dont worry Arunma - there is only so much physics the brain can handle anyway.

allright:

let's accept that a person's present moment changes proportionately with the processing speed of the brain, and see where that leads us. This should be interesting!

lets take this slowly:

if my brain processing speed increases, then so too will the rate at which my present moment changes. (and conversely)
so if my brain processing speed doubles, then time will literally pass twice as fast for me.
so if we have two people who have experienced a present moment (t=0) together, one with brain at normal speed and the other at double speed, then for any greater time, they will no longer share the same moment.

does this make sense?