Time Travel... the fly in the ointment

[skepticalbip]

That was my point. Nor do the models describe how the past exists in order to be able to 'rewind' time, or return to past states of the world, other than vague mentions, such as worm holes, etc.

There are two very different things here. The past existing is one thing. Being able to return to the past is quite another. Models can only describe... they can't demonstrate. Demonstrating can only be accomplished with testing and only if someone can figure out a way to design a test and the model is right. However, an interpretation of the model is that the past exists.

You have to take Brian Greene with a large dose of salt, just as with Michio Kaku when they are on programming aimed at the general public. Their public persona tends to present the fringes of speculative interpretation on science because it makes for more interesting TV than a lecture on generally accepted understandings in science.

True, but that doesn't mean the scientific principles they are referring to are not valid, even if some of it is not testable such as string theory. If you have access to a plausible description for a return to past states of matter/energy, I'd interested in seeing it.

The principles can not be said to be valid until they have been verified through testing. Most proposed models don't make it. Relativity has done damned well so far in its extensive testing.

I once had great hopes for string theory but lost most confidence in it when they gave up trying to find unique solutions and declaired that all their solutions were valid (somewhere, even if not in our universe). Many string theorists now remind me of the Pathagarians who derailed progress for several hundred years because they were so enamored with the beauty of their mathematics, believing that it was so beautiful that it had to be descrobing reality. Will string theory eventually contribute something useful? I hope so.

No I don't have access to a plausible description for a return to past states of matter/energy. I don't think it is possible and don't think it will ever be possible but I wouldn't absolutely say "never". The universe is too fucking strange and we know so little.

 

[skepticalbip]

Now you reject it to give your Newtonian analysis of where the sun is rather than Einstein's analysis of where/when the sun is.

Nonsense.

You simply have muddled thinking.

You think you are looking at the past when you are looking at light hitting your eye in the present.

And you think the light that leaves the sun is the same light that hits your eye, but it has been altered by it's journey.

This has nothing to do with a dichotomy between Newtonian understanding and current understandings.

Here is a simplified (no math) explanation for you. If you accept Einstein's rather than Newton's vision of reality then the past, present, and future are.

And remember, we already know that Newton didn't get it quite right even if there was no Einstein. Did Einstein get it "righter"?

 

[Archimedes]

True enough. And at any point your experience of the river is only of the bit you are currently in. But only a total idiot would suggest that the rest of the river, from headwaters to estuary, did not exist.

And it seems to me that untermensche's repeated question of where the past is, is like asking when upstream in the river you're travelling down is. It seems to be a bit of a category error asking people to point at a location in space in order to identify a location in time (or entire continuum or locations) is.

Like insisting upon a point on the X-axis of a graph to identify a point on the Y-axis.

 

[untermensche]

Here is a simplified (no math) explanation for you. If you accept Einstein's rather than Newton's vision of reality then the past, present, and future are.

And remember, we already know that Newton didn't get it quite right even if there was no Einstein. Did Einstein get it "righter"?

This is pretty bad.

They simply assume their conclusions.

They start by saying there is a big loaf of space time that can be cut in different ways.

And of course they conclude there is a big loaf of space time that can be cut in different ways.

It doesn't prove anything.

 

[skepticalbip]

Here is a simplified (no math) explanation for you. If you accept Einstein's rather than Newton's vision of reality then the past, present, and future are.

And remember, we already know that Newton didn't get it quite right even if there was no Einstein. Did Einstein get it "righter"?

This is pretty bad.

They simply assume their conclusions.

They start by saying there is a big loaf of space time that can be cut in different ways.

And of course they conclude there is a big loaf of space time that can be cut in different ways.

It doesn't prove anything.

Is that you Isaac?

 

[untermensche]

This is pretty bad.

They simply assume their conclusions.

They start by saying there is a big loaf of space time that can be cut in different ways.

And of course they conclude there is a big loaf of space time that can be cut in different ways.

It doesn't prove anything.

Is that you Isaac?

Laugh all you want.

In that video all they did was say a loaf was possible and then assumed it was possible.

The error I see is the narrator starts by talking about a "slice of now" and then switches to a "slice of light".

The now doesn't change, the light does.

This goes to the comment about seeing the past by seeing the sun. It is the same error. Confusing an event with the light coming from that event.

The event is the instant the light leaves the sun.

We do not see that event when we see the sun. We do not see the past.

Time is a moving "wave", as is so much in the universe, and we all move within it.

There is some flexibility on where we ride the wave based on our speed, but that is all.

And this is based on evidence not speculation.

You have it absolutely backwards.

You claim that all is permanent.

The truth is, change is permanent. The burnt paper does not become paper again. To think it is always the paper somehow is to have a delusion.

 

[bilby]

Is that you Isaac?

Laugh all you want.

In that video all they did was say a loaf was possible and then assumed it was possible.

The error I see is the narrator starts by talking about a "slice of now" and then switches to a "slice of light".

The now doesn't change, the light does.

This goes to the comment about seeing the past by seeing the sun. It is the same error. Confusing an event with the light coming from that event.

The event is the instant the light leaves the sun.

We do not see that event when we see the sun. We do not see the past.

Time is a moving "wave", as is so much in the universe, and we all move within it.

There is some flexibility on where we ride the wave based on our speed, but that is all.

And this is based on evidence not speculation.

You have it absolutely backwards.

You claim that all is permanent.

The truth is, change is permanent. The burnt paper does not become paper again. To think it is always the paper somehow is to have a delusion.

You need to learn that there is a difference between "I cannot understand this" and "This is delusional nonsense". The possibility that the problem is your lack of understanding, rather than other people's, never seems to cross your mind, and that is a big failure.

IF this idea were delusional or nonsensical, THEN you would be able to present an argument showing this. Instead, all you have presented is assertions that it cannot be so, and arguments that rely on flawed understanding of what is being proposed - all of which tells us nothing about reality; It is just your avowed belief.

You claim "... this is based on evidence not speculation." But you provide no evidence; apparently your word is sufficient.

You are too quick to rule out the possibility of a four dimensional spacetime, in favour of a three dimensional space that is subject to a totally different phenomenon called time; You have not presented a shred of evidence as to why either one of these must be true, or must be untrue. We know your opinion; now it is time to back that opinion with some evidence.

 

[skepticalbip]

Is that you Isaac?

Laugh all you want.

In that video all they did was say a loaf was possible and then assumed it was possible.

The error I see is the narrator starts by talking about a "slice of now" and then switches to a "slice of light".

The now doesn't change, the light does.

This goes to the comment about seeing the past by seeing the sun. It is the same error. Confusing an event with the light coming from that event.

The event is the instant the light leaves the sun.

We do not see that event when we see the sun. We do not see the past.

Time is a moving "wave", as is so much in the universe, and we all move within it.

There is some flexibility on where we ride the wave based on our speed, but that is all.

And this is based on evidence not speculation.

You have it absolutely backwards.

You claim that all is permanent.

I have claimed nothing. I have only offered what Einstein's model of spacetime is. The simplified video that was made on a level that even eighth graders can grasp was only a description of what the model is. It wasn't trying to prove anything. It was only describing spacetime. That model is necessary for Einstein's General Relativity and General Relativity has withstood almost a hundred years of testing by critics trying to disprove GR who know a hell of a lot more about physics than either of us.

The truth is, change is permanent. The burnt paper does not become paper again. To think it is always the paper somehow is to have a delusion.

Physics models require a lot more than just pulling erroneous beliefs out of your arse.

You are, of course, welcome to say that Einstein was a idiot to think that time was a dimension when actually "time is a moving 'wave'" if you wish but to be taken seriously you will have to tie that assertion with a model that is better at explaining events we observe in the universe than General Relativity which has proved to be damned precise.

 

[untermensche]

I have claimed nothing. I have only offered what Einstein's model of spacetime is.

You presented a video where some theorists went from saying something is possible to immediately saying it is absolute truth, despite any evidence.

You haven't explained a damn thing.

But again the position I have trouble with is the idea that the past has permanent existence and if you are not claiming this then you have nothing I care about.

 

[bilby]

I have claimed nothing. I have only offered what Einstein's model of spacetime is.

You presented a video where some theorists went from saying something is possible to immediately saying it is absolute truth, despite any evidence.

You haven't explained a damn thing.

But again the position I have trouble with is the idea that the past has permanent existence and if you are not claiming this then you have nothing I care about.

'Permanent' isn't really a sensible word to use; it implies that the objects in the past continue unchanged into the future, which is not correct.

The past is real; it existed. From some points of view, things we call 'the past' are in 'the future'; and according to Einstein, there is no reason to consider our point of view to be special or preferred.

There are no preferred reference frames; the perception of time is not absolute, but is determined by the choice of reference frame; what in my reference frame I call 'the past' is therefore 'the present' in some valid reference frames, and is 'the future' in other valid reference frames.

Of course, Einstein may be wrong about all this; but so far you have presented no reasons to think that he is. Or was. Or will be.

 

[untermensche]

You presented a video where some theorists went from saying something is possible to immediately saying it is absolute truth, despite any evidence.

You haven't explained a damn thing.

But again the position I have trouble with is the idea that the past has permanent existence and if you are not claiming this then you have nothing I care about.

'Permanent' isn't really a sensible word to use; it implies that the past continues into the future.

The past is real; it existed. From some points of view, things we call 'the past' are in 'the future'; and according to Einstein, there is no reason to consider our point of view to be special or preferred.

There are no preferred reference frames; the perception of time is not absolute, but is determined by the choice of reference frame; what in my reference frame I call 'the past' is therefore 'the present' in some valid reference frames, and is 'the future' in other valid reference frames.

Of course, Einstein may be wrong about all this; but so far you have presented no reasons to think that he is. Or was. Or will be.

This is not Einstein.

This is speculation beyond Einstein.

And if the universe is as that video purports then there is a preferred reference frame. The view from the outside as they portray.

 

[bilby]

'Permanent' isn't really a sensible word to use; it implies that the past continues into the future.

The past is real; it existed. From some points of view, things we call 'the past' are in 'the future'; and according to Einstein, there is no reason to consider our point of view to be special or preferred.

There are no preferred reference frames; the perception of time is not absolute, but is determined by the choice of reference frame; what in my reference frame I call 'the past' is therefore 'the present' in some valid reference frames, and is 'the future' in other valid reference frames.

Of course, Einstein may be wrong about all this; but so far you have presented no reasons to think that he is. Or was. Or will be.

This is not Einstein.

This is speculation beyond Einstein.

And if the universe is as that video purports then there is a preferred reference frame. The view from the outside as they portray.

I haven't watched the video due to bandwidth constraints - I might look at it later.

There is nothing in the post of mine, to which you replied here, that goes beyond what Einstein described.

If the video does say that there is a preferred reference frame, then it is wrong about that. Of course, you have demonstrated your inability to understand this topic, so I am going to reserve judgement on whether the video is in error, or whether it is your interpretation of it that is in error; at least until I have the chance to see it for myself.

 

[DBT]

There are two very different things here. The past existing is one thing. Being able to return to the past is quite another. Models can only describe... they can't demonstrate. Demonstrating can only be accomplished with testing and only if someone can figure out a way to design a test and the model is right. However, an interpretation of the model is that the past exists.

The models that I've seen appear to me to be too sketchy in terms of both the nature of a time dimension (block time/eternalism) and the possibility (and means) of returning to the past...to say the least (the wormhole model for example).

The principles can not be said to be valid until they have been verified through testing. Most proposed models don't make it. Relativity has done damned well so far in its extensive testing.

I once had great hopes for string theory but lost most confidence in it when they gave up trying to find unique solutions and declaired that all their solutions were valid (somewhere, even if not in our universe). Many string theorists now remind me of the Pathagarians who derailed progress for several hundred years because they were so enamored with the beauty of their mathematics, believing that it was so beautiful that it had to be descrobing reality. Will string theory eventually contribute something useful? I hope so.

String theory appears, to me, to allow all possible worlds to be realized (many worlds interpretation), but not necessarily a return to past states within any of these worlds.

No I don't have access to a plausible description for a return to past states of matter/energy. I don't think it is possible and don't think it will ever be possible but I wouldn't absolutely say "never". The universe is too fucking strange and we know so little.

Fair enough.

 

[untermensche]

This is not Einstein.

This is speculation beyond Einstein.

And if the universe is as that video purports then there is a preferred reference frame. The view from the outside as they portray.

I haven't watched the video due to bandwidth constraints - I might look at it later.

There is nothing in the post of mine, to which you replied here, that goes beyond what Einstein described.

If the video does say that there is a preferred reference frame, then it is wrong about that. Of course, you have demonstrated your inability to understand this topic, so I am going to reserve judgement on whether the video is in error, or whether it is your interpretation of it that is in error; at least until I have the chance to see it for myself.

Disagreeing with interpretations is not having an inability to understand.

It does not follow logically that simply because the universe is a 4 dimensional universe that the past is "recorded" somehow and "stored" somehow for eternity.

A 4 dimensional universe is simply a universe where 3 dimensional objects can move and change. There is nothing hidden or invisible about a 4th dimension. It is the freedom to change not a recording device.

 

[Speakpigeon]

Assume, to make us able to even properly imagine this, that space-time consited of only two space coordinates (x,y) and time. Its the space-time pf flatland. Now let space origo be at the center of the sun then the earth will be a very thin pasta spiral spiralling in the direction of time. Let us view time as up and we will see the circling earth as a spiral around the vertical rod that is the sun. Now think of a flatland being on the flatland earth. (Assume it is a circle) then its movements on the earth will result in a complicated swirl around this spiral that is the earth. But how about the flatlanders "now"? That is at each position of the flatlanders life curve. But why then do we only experience a short now? Because we perceive locally: at each time we only perceive what is at that position in space time.

But how/why do we move in time?

If time exists (as opposed to just the present "now") then we are back to this idea of a block space-time, in your example a three-dimensional one. If so then we are not moving (see bilby's remark on this). Rather, there is a continuous, one-dimensional collection of points (a curve) in this block space-time that coincide with our experience of the universe. At each point as you said we perceive the local patch yet in fact this is not the same us. Each me is different from the previous and the next ones and each has its own perception of the local bubble. So the question is not exactly of how we move in time (we don't) but how we come to experience one particular space-time point and not others.
EB

 

[Speakpigeon]

A 4 dimensional universe is simply a universe where 3 dimensional objects can move and change. There is nothing hidden or invisible about a 4th dimension. It is the freedom to change not a recording device.

A four-dimensional universe is just a reality in which there are four degrees of (apparent) freedom, meaning only that any particular state of this reality is only constrained by having only these four degrees of freedom. There is some evidence but no hard proof that time exists and that we somehow travel along with it or in it. All we really know is a particular point in what only seems to be a three-dimensional space together with what seems to be our memory of past events. If we accept that our memory is evidence at all, then we can go a bit further and say that time seems to exist and that there seems to be a distinction between time and space. However, this distinction is only based on this appearance that the universe now seems to be a consequence of the universe just before now accroding to our memory. Yet, the geometry of space and the furniture of space (basically, the distribution of energy throughout space) appear to be no less continuous than time appears to be. It seems to me that the distinction between space and time is a distinction given by our native cognitive model of reality. Science (Relativity) seems to support a similar distinction with the speed of light as a fundamental relation between different space-time locations (while there is no similar relation between different space locations). Yet, even if that distinction is real, it does not follow that time or space as we think of them are real. They may instead be just degrees of apparent freedom that our basic coginitve model of reality represent as space and time and that science represents as space-time with a constraint on the speed of interactions.
EB

 

[untermensche]

Yet, the geometry of space and the furniture of space (basically, the distribution of energy throughout space) appear to be no less continuous than time appears to be. It seems to me that the distinction between space and time is a distinction given by our native cognitive model of reality.

Our consciousness is the consciousness of an ever moving "now".

If the past and future are equally as real as this "now" the question is; why is consciousness at this now and how does it move along?

 

[bilby]

Yet, the geometry of space and the furniture of space (basically, the distribution of energy throughout space) appear to be no less continuous than time appears to be. It seems to me that the distinction between space and time is a distinction given by our native cognitive model of reality.

Our consciousness is the consciousness of an ever moving "now".

If the past and future are equally as real as this "now" the question is; why is consciousness at this now and how does it move along?

Why is that the question?

Take a rock in interstellar space. Why is it at the particular location it is at, and how does it move?

The answers are 'because it has to be somewhere' and 'it remains in constant motion because no forces act on it'.

Not particularly important questions, with not particularly edifying answers. But perhaps the rock would think them important enough to describe them as the question.

 

[untermensche]

Our consciousness is the consciousness of an ever moving "now".

If the past and future are equally as real as this "now" the question is; why is consciousness at this now and how does it move along?

Why is that the question?

Take a rock in interstellar space. Why is it at the particular location it is at, and how does it move?

The answers are 'because it has to be somewhere' and 'it remains in constant motion because no forces act on it'.

According to you it is in no specific location. If the future is as real as the present then nothing has a specific location. And since we don't know the future we really have no idea where anything is because we don't know where it will be.

How is it we are able to stand in the middle of all this and see a rock in only one location?

How is the realness of the future and the past divided by us so we experience a now?

 

[Juma]

Why is that the question?

Take a rock in interstellar space. Why is it at the particular location it is at, and how does it move?

The answers are 'because it has to be somewhere' and 'it remains in constant motion because no forces act on it'.

According to you it is in no specific location. If the future is as real as the present then nothing has a specific location. And since we don't know the future we really have no idea where anything is because we don't know where it will be.

How is it we are able to stand in the middle of all this and see a rock in only one location?

How is the realness of the future and the past divided by us so we experience a now?

Why do we experience a here?