If only two points exist does time flow?

[argo]

 

Calling the points A and B and considering established physics always applies then A and B move through time according to relativity. Point A stands still as B moves from A’s perspective and point B stands still as A moves from B’s perspective, if A and Bs’ perspectives can be considered a microcosm of the real universe then, if only in this relative way, we have a static universe where every point considers itself fixed at point 0,0.

A spacetime graph is a concept of relativity that works only AFTER the perspective is chosen, choosing A as 0,0 on the graph I can then show how B is moving m/s, and choosing B as 0,0 needs to be done first before A can be shown to move, the 0,0 point is always fixed relative to both A anb B and must exist before the concept of spacetime can.

I think there is a question here as to how two points that consider themselves fixed move in relation to one another, I think, and please correct me if I am wrong, the established view is A and B exist at the same time allowing A and B to flow through time together BUT if they both exist at the spacetime 0,0 point at the same time how is this possible? Ever?    No really how is this possible, please give an answer?

If A and B MUST ALWAYS exist at different times as I suggest then every spacetime graph that exists is at a different time and is effectively just a 0,0 point making up a relative universe.

There is clearly something wrong with the established model saying A and B exist together at the same time which allows the perception of time flow THEN also saying A and B exist at different times which allow relativity. Perhaps this is my fundamental mistake, perhaps the established view of relativity is NOT about different times at all and I just don’t understand the science properly.

 

[Markus Hanke]

19 minutes ago, argo said:

There is clearly something wrong with the established model saying A and B exist together at the same time which allows the perception of time flow THEN also saying A and B exist at different times which allow relativity. Perhaps this is my fundamental mistake, perhaps the established view of relativity is NOT about different times at all and I just don’t understand the science properly.

I’m having trouble understanding your point, I’m afraid. There is no absolute time nor is there absolute space, so it is irrelevant just where you place your point of origin. Either observer can choose any suitable coordinate system he/she likes, as this makes no difference to the physics. What is important is only the relationship between the observers, and this is something they both agree on. Specifically, and assuming they are inertial observers in flat spacetime, their two reference frames are related by a simple hyperbolic rotation about some angle, and the spacetime interval AB is the same as the spacetime interval BA. So there are no contradictions. More generally, you can actually prove that no matter how you set up your observers, there are never any inconsistencies.

It should be mentioned also that spacetime is the collection of all events, i.e. of all points in space at all instances in time; there is not actually any concept of “flow of time”, there are only geometric relationships between events in spacetime. The theory of relativity cannot answer the question as to why we experience a “flow” from past to the future, as this is outside its scope.

[Strange]

1 hour ago, argo said:

Calling the points A and B and considering established physics always applies then A and B move through time according to relativity.

Things don't "move through time" in relativity.

And, in particular, "points" don't move at all. A "point" is coordinate in space. In relativity, you need to consider the space-time coordinates of objects or observers (that may be moving relative to one another).

1 hour ago, argo said:

if A and Bs’ perspectives can be considered a microcosm of the real universe then, if only in this relative way, we have a static universe where every point considers itself fixed at point 0,0.

That doesn't really make any sense. Points are defined with reference to a coordinate system (think of a sheet of graph paper, for example) which will have an origin (0,0) with all other points having non-zero coordinates (x,y). In reality, you need to deal with the (x,y,z,t) coordinates of each event. The Lorentz transform then gives us a way of converting between those coordinates measured by observer A to those measured by observer B in relative motion (x',y',z',t').

1 hour ago, argo said:

I think, and please correct me if I am wrong, the established view is A and B exist at the same time allowing A and B to flow through time together

If A and B are in relative motion, then there is no "same time".

1 hour ago, argo said:

BUT if they both exist at the spacetime 0,0 point at the same time how is this possible?

They don't exists at the same point (or at least, not for long if they are in relative motion). 

And, "0,0" is not a spacetime coordinate, it is a 2D coordinate.

1 hour ago, argo said:

There is clearly something wrong with the established model

It is far more likely that you simply don't understand it.

You might find the following useful:

https://www.khanacademy.org/science/physics/special-relativity#minkowski-spacetime

https://ocw.mit.edu/courses/physics/8-20-introduction-to-special-relativity-january-iap-2005/

[argo]

7 hours ago, Markus Hanke said:

There is no absolute time nor is there absolute space,

I am not saying there is am I? If A and B ALWAYS exist at different times or exist at the same time how does that then invoke either way that A or B is a preferred frame? I don’t see how you came to that conclusion and therefore don’t see how this has anything to do with the question.

The question is specifically about time flow in relativity and I agree there is not actually any concept of “flow of time” in relativity which is specifically why I can ask the question. There is more than one line of inquiry so is there any reason to bar how I am asking this question because you have not provided any.

It is irrelevant where you decide A is but you can’t know if B is moving until that decision is made first. Again I am not saying it is relevant WHERE A is but the decision to say it is ‘at a certian 0,0 point’, wherever that may be, is completely relevant if you wish to know the geometric relationships between events in spacetime, so again this has nothing to do with the question of whether A and B exist at the same time or not.

 

The Lorenz transformation is a brilliant piece of mathamatics that converts the measurements from different observerses,in a 4 dimensional continuum, it is outstanding work but it does not have anything to do with my question that asks if there even is a 4 dimensional continuum. Don’t you think this question should come first?  

Yes a spacetime graph is xyzt of course, 0,0 is just a 2D shorthand for the intersection which had no consequence to the question. Good point though.

If A and B are in relative motion, then there is no "same time".  You mean absolute time which has nothing to do with my question, you refer to the fact that there is no privileged reference frame and I totally agree, please explain how saying A must always exist at a different time to B invokes absolute time or please refrain from using the argument, It’s just a play on words and misrepresents what I am asking as far as i can see.

 

wiki

These notions imply that absolute space and time do not depend upon physical events, but are a backdrop or stage setting within which physical phenomena occur.

 I am not remotely talking about a fixed backdrop just two points but I understand that if I first think about a 4 dimensional continuum that saying the ‘same time’ invokes the idea of a backdrop. Try not assuming anything because until you have an answer to the base question im asking first then how can you assume this version of spacetime even exists?  

Why is it so unreasonable to ask if A and B exist at the same time or not? There is a chronological order to things, you ask if there is cake before you ask to eat it.

Thanks heaps for your responses, i am trying to falsify everything i say and everything helps.

[Strange]

3 hours ago, argo said:

It is irrelevant where you decide A is but you can’t know if B is moving until that decision is made first.

You could tell that object B is moving even without defining a coordinate system. But that isn't really relevant. You do need to define the coordinate system of A and B in order to make any measurements.

3 hours ago, argo said:

The Lorenz transformation is a brilliant piece of mathamatics that converts the measurements from different observerses,in a 4 dimensional continuum, it is outstanding work but it does not have anything to do with my question that asks if there even is a 4 dimensional continuum.

Asking if there "really is" a 4D space-time is a question for philosophy, not science. We model the world using that concept and it gives us the right answers. That is all you can ask science to do.

3 hours ago, argo said:

wiki

Are you quoting something from Wikipedia? If so, please make clear what you are quoting and where from.

3 hours ago, argo said:

These notions imply that absolute space and time do not depend upon physical events, but are a backdrop or stage setting within which physical phenomena occur.

Which notions?

And there is no absolute space and time.

[Markus Hanke]

14 hours ago, argo said:

I am not saying there is am I?

No, but you are tacitly assuming it in the way you are thinking about the situation. For example in your next sentence:

14 hours ago, argo said:

If A and B ALWAYS exist at different times (...)

Different times according to who? Since time in relativity is a purely local concept, simultaneity becomes relative too. The same is true for “always” - it’s an observer-dependent concept.

14 hours ago, argo said:

but the decision to say it is ‘at a certian 0,0 point’, wherever that may be, is completely relevant if you wish to know the geometric relationships between events in spacetime

Actually, it isn’t. The metric is a tensorial quantity, so the relationship between events in spacetime does not depend on your choice of coordinates. In the specific case of Special Relativity, you don’t even need to pick any coordinate system at all - you need to know only that the metric is constant.

15 hours ago, argo said:

it does not have anything to do with my question that asks if there even is a 4 dimensional continuum

This is a valid question, but it is not how I understood your OP. So I may have misunderstood you. Perhaps you can clarify again exactly what it is that you are asking, maybe in more general terms?

15 hours ago, argo said:

Why is it so unreasonable to ask if A and B exist at the same time or not? There is a chronological order to things, you ask if there is cake before you ask to eat it.

In relativity there is a causal order to things, but not a chronological one (i.e. one that is based on clock readings), because time is a relative concept that not all observers agree on. The notion of “at the same time” is thus not shared by all observers. What is shared between all observers is the spacetime interval between events, specifically whether it is a timelike, spacelike, or null interval. This imposes a causal structure on spacetime, which everyone agrees on.

[argo]

16 hours ago, Strange said:

You could tell that object B is moving even without defining a coordinate system.

By the bulging center of a rotating mass due to centrifugal force I think, would point A bulge if it were the only point that existed, I don’t think such a fundamental point could bulge.

16 hours ago, Strange said:

You do need to define the coordinate system of A and B in order to make any measurements.

Yes and you need to have an original point to have a universe unless that universe just always was

16 hours ago, Strange said:

Asking if there "really is" a 4D space-time is a question for philosophy, not science. We model the world using that concept and it gives us the right answers. That is all you can ask science to do.

Invoking a 4D universe then adding points of origin within it is not the only line of inquiry, this is the Stephen Hawkins philosophy that the universe just always was, I understand that a lot of work has been done to model the world using that concept and come up with answers that fit but it is far from perfect and there are glaring inconsistencies, wave –particle duality for example.

Markus i understand the arguments your making as a line of inquiry in 4D spactime, it is a legitimate line of inquiry but this is not about that line of inquiry, this is a new line of inquiry that i think fits the evidence in a completely different version of spacetime, there is a different way to explain things and adherence to the original way only blocks any new inquiry. I am talking about a hypothetical 2 point universe and asking if the two points exist at the same time as the basis of this new line of inquiry. 

 

A different line of inquiry may be the universe didn’t always just exist, but only a single point exists at a time and one by one they make up a quite different timespace universe. If all science can do is make inquiry and see if the evidence fits then I think this is what I am trying to do.

From what I see from all the posts you all think this is not a legitimate line of inquiry simply because it does not have the philosophy that the universe just always existed, every argument invokes this version of spacetime to dispel any other versions conveniently stopping any further inquiry. I don’t know if it’s right or wrong, I only bought it up because it seems to fit the evidence from relativity and explain wave-particle duality all in one and I wanted to discuss it with approximately educated people. I have consistently explained why this is not an excuse to not answer the question but I’m just being ignored.

I think I’m done

[Strange]

2 minutes ago, argo said:

Yes and you need to have an original point to have a universe unless that universe just always was

What does that mean? We can define an coordinate system without considering the origin of the universe (if that is what you are implying).

4 minutes ago, argo said:

this is the Stephen Hawkins philosophy that the universe just always was, I understand that a lot of work has been done to model the world using that concept and come up with answers that fit but it is far from perfect and there are glaring inconsistencies, wave –particle duality for example.

This doesn't seem to have anything to do with your question. I think you need to focus on one subject at a time. If you want to discuss whether the universe has always existed or not, start a thread on that. If you want to discuss quantum theory, then start a thread on that. (There are no "glaring inconsistencies" in quantum theory.)

5 minutes ago, argo said:

I am talking about a hypothetical 2 point universe and asking if the two points exist at the same time as the basis of this new line of inquiry. 

You can define two "points" (events) that exist at the same time, for example (x₁, y₁, z₁, t) and (x₂, y₂, z₂, t) but they must be in the same frame of reference (ie. not in relative motion).

It really isn't clear what you are asking, or what you are trying to say. You need to develop a mathematical model instead of relying on such vague statements.

8 minutes ago, argo said:

From what I see from all the posts you all think this is not a legitimate line of inquiry simply because it does not have the philosophy that the universe just always existed

I don't see how that is relevant. (And in General Relativity, the universe has not always existed; if you go back to t=0 you end up at a singularity; a single zero-sized point. But that is irrelevant to special relativity, which is what your question seemed to be about.)

9 minutes ago, argo said:

I don’t know if it’s right or wrong, I only bought it up because it seems to fit the evidence from relativity and explain wave-particle duality all in one and I wanted to discuss it with approximately educated people.

You have just introduced wave-particle duality, which wasn't part of your OP, with no explanation of how it is relevant. SR says nothing about wave-particle duality.

[Markus Hanke]

18 hours ago, argo said:

I have consistently explained why this is not an excuse to not answer the question but I’m just being ignored.

I honestly don’t understand what it actually is you are asking - could you reformulate your question in a different way? At the moment you are bringing up many different concepts which are not really related, for example SR mixed with wave-particle duality, or the evolution of the universe.

[argo]

17 hours ago, Strange said:

18 hours ago, argo said:

Yes and you need to have an original point to have a universe unless that universe just always was

What does that mean? We can define an coordinate system without considering the origin of the universe (if that is what you are implying).

If only two points exist does time flow? 

this is what i am talking about above, is there a universe or is there just two points, or in this case an original point.The hypothetical question you are supposed to be focusing on and the cause and effect issue where you use an established timespace effect without having a cause for it. You say the question doesn't make sense because you are using this model.

i need you to focus on the question, give an answer or an explanation why not would be nice ty very much.

18 hours ago, Strange said:

You can define two "points" (events) that exist at the same time, for example (x₁, y₁, z₁, t) and (x₂, y₂, z₂, t) but they must be in the same frame of reference (ie. not in relative motion).

You are using the established spacetime model. I am not disagreeing with you if this is the model we are using but as far as the hypothetical 2 point universe question is concerned that has not been established yet.

 

[Strange]

1 hour ago, argo said:

this is what i am talking about above, is there a universe or is there just two points, or in this case an original point.

It is not clear what you mean.

Are you defining a 2D "universe" which consists entirely of two points, for example (0,0) and (1,1). That isn't much of a universe and there are only spatial dimensions so there is no time to "flow".

(There would actually be four points in such a universe: 0,0 0,1 1,0, 1,1)

I suspect that is not what you are asking, but I don't know how else to interpret what you are saying. Do you mean two "points" or do you mean two objects (of insignificant size and mass)?

1 hour ago, argo said:

You are using the established spacetime model. I am not disagreeing with you if this is the model we are using but as far as the hypothetical 2 point universe question is concerned that has not been established yet.

OK. So you do mean a model that isn't described in terms of space-time. In which case, how are you modelling time in order to allow it to "flow" or not?

1 hour ago, argo said:

i need you to focus on the question, give an answer or an explanation why not would be nice ty very much.

This is your model. Only you can define what "time" means in this model. 

Edited August 17, 2018 by Strange

[Markus Hanke]

2 hours ago, argo said:

If only two points exist does time flow?

If you have only two points that are not part of the same manifold, then there is no spacetime, and it is not possible to establish any relationship between those points. Notions of space and time are thus meaningless in such a scenario.

[argo]

Point A and B are physical points or a reference frame containing exactly one physical point each. Such a point would be a fundamental point of unknown composition as far as i know. Being of unknown origin i cant really say how many dimensions the point is that gives rise to a fundamental  physical point. I should have been clearer.

5 hours ago, Markus Hanke said:

If you have only two points that are not part of the same manifold, then there is no spacetime

Well not the established concept of spacetime.

If every point is its own geometry this seems to satisfy relativity; i,e. every point existing at a different time. This is the model i have been describing all along i thought.  

5 hours ago, Markus Hanke said:

and it is not possible to establish any relationship between those points

Two possible relationships, firstly if every point exists at a different time then we could be talking about just one point existing with itself at different times, there is no need to have a second point in this concept and secondly as they are just single points they would need to exist somewhere. This version of spacetime  may be all these points if different time also means different place. There is no background manifold to be part of, each point is its own manifold.

i don't know if its true nor do i have math skill to prove it, but when i look at the evidence from relativity it seems to fit.

[Strange]

6 minutes ago, argo said:

Two possible relationships, firstly if every point exists at a different time

IF you are using time as a dimension (as in relativity) then you no longer have just two points.

IF you are using a different model of time, then you need to say what it is.

You refer to relativity but then reject "the established spacetime model". So which is it: do you want to discuss relativity, or do you want to discuss another model that you have made up?

9 minutes ago, argo said:

Such a point would be a fundamental point of unknown composition as far as i know. Being of unknown origin i cant really say how many dimensions the point is that gives rise to a fundamental  physical point.

As you are the one who has invented this "two pint mode" only you can answer these questions.

If anyone else attempts to answer them (which can only be attempted based on known science) you say you don't want to talk about "the established spacetime model".

10 minutes ago, argo said:

this seems to satisfy relativity; i,e. every point existing at a different time

Relativity doesn't say anything like that.

[argo]

if only two points exist is a hypothetical question as stated, i asked it to highlight that in a universe where you only have two points you must make a choice whether the points exist at the same time or not.

in this answer to markus-

19 hours ago, Markus Hanke said:

If you have only two points that are not part of the same manifold, then there is no spacetime

when asked about being part of the same geometric manifold i explained that every point may be existing at the different time , i am sorry if i didn't make this clear enough.

14 hours ago, argo said:

If every point is its own geometry this seems to satisfy relativity;

15 posts in and still no clear answer from you on the original question, no wonder the original  question is hanging around getting mixed in with a question that requires i move on to answer. 

14 hours ago, Strange said:

IF you are using time as a dimension (as in relativity) then you no longer have just two points.

ok moving on from the question you dont want to answer, yes i am using time as a dimension containing exactly one fundamental point, this spacetime model just happens to be different from the established one, i am not just making it up out of nowhere.

Using time as a dimension (as in relativity ) every point in this model would always be in its own dimension always at different times, this is not the case with the established model of spacetime, that can group some or all points together in  reference frames or to put it another way, a common time for multiple points. 

I am not sure how the established model of spacetime allows a point to exist at different times on one hand and together in reference frames at the same time on the other hand, in my version a point is exclusively at different times. This is the ONLY distinctions i am making between the two models, the question-if only two points exist does time flow- should have been answered long ago, i hope you understand its design purpose was to see if you simply invoke the abilities that established spacetime has to manipulate time.

its science, things need to be picked apart and i wouldnt have it any other way but im not the enemy either.

[Strange]

42 minutes ago, argo said:

15 posts in and still no clear answer from you on the original question

That is because your question is so poorly defined. You don't like the answers you get (they don't seem to fit with the model in your head) and yet you are unable to clarify the question.

42 minutes ago, argo said:

ok moving on from the question you dont want to answer,

Don't be silly. It has nothing to do with "wanting" to answer. I am trying to understand what you are asking; and I am trying to answer based on what I can understand of your question.

42 minutes ago, argo said:

yes i am using time as a dimension containing exactly one fundamental point

Then it isn't a dimension.

It is not clear if you mean something non-standard by "dimension" or by "point".

A dimension consists of an infinite number of points: roughly it is a measurement of "distance" (which can be spatial or temporal). If there is only one point, then there is no measurement possible.

42 minutes ago, argo said:

Using time as a dimension (as in relativity ) every point in this model would always be in its own dimension always at different times

Why? 

And what does "in its own dimension" mean? 

Are you now referring to points in a single (spatial dimension)? Are you trying to say that every point along one dimension (e.g. every point along x) is at a different time? Why would that be the case?

In this case, these don't seem to be "dimensions" in the usual meaning of the word; one of the defining characteristics of dimension is that they are independent. But if you are making the position in the time dimension dependent on the position on one of the time dimensions, then they are no longer independent.

42 minutes ago, argo said:

I am not sure how the established model of spacetime allows a point to exist at different times

I'm not sure it does. You seem to back to thinking of time as some sort of universal thing independent of space.

If by "point" you mean a location in 3D spatial coordinates, then you cannot talk about that as if it were independent of time.

In relativity, things are defined in terms of 4D space-time coordinates ("events"). When you make measurements from different frames of reference, then both the time and the time coordinates change. So to take about "a point to exist at different times" doesn't really make sense.

When viewed from another frame of reference, an event will be at a different time (as you put it) but it will also be at a different place.

Basically, the coordinate system as seen from one frame of reference is rotated when seen from another frame of reference.

 

Edited August 18, 2018 by Strange

[jajrussel]

If I tried to figure out every thing said in this conversation it would probably take me days if not a whole lot longer to unravel my confusion. A good starting point for me might be if I actually knew that time flows.

I move, things around me move. How can I take an accurate measure of time if time also moves. Unless, when you say time flows you don't actually mean it moves. Which to me would mean time is considered static, and if time is static how does flow apply to time?

In an expanding universe both point A and point B move. My assumption is that time is relative, so unless I want to account for, or need to account for an expanding universe my measure should be reasonably suitable to my purpose.

I may be wrong but it seems that to my understanding of relativity that in order for me to get a reasonably accurate measure of time, if, it is required that time is said to flow, then it must flow at the same rate I do, so my position seems to require that time be static, or at least appear to be static, initially. Wouldn't the rate of change being consistent with my velocity be considered to be static?

Still, I reach a point of confusion? At C, does time stop, or is it me that stops? 

Assuming, that this is a theoretical thought and C is allowed?

Well, assuming theoretical, I guess time flow is okay, even if confusing.

Still, using my imagination I can Invision time flowing in a wave like pattern throughout the universe due to relativity. It speeds up it slows down, it speeds up it slows down, etc. But then the annoying part of me steps in and says, okay, but is time actually flowing, or am I the one actually speeding up and slowing down?

[Strange]

24 minutes ago, jajrussel said:

If I tried to figure out every thing said in this conversation it would probably take me days if not a whole lot longer to unravel my confusion.

I wouldn't bother trying!

24 minutes ago, jajrussel said:

A good starting point for me might be if I actually knew that time flows.

This is a common metaphor used in daily life. It has nothing to do with relativity.

25 minutes ago, jajrussel said:

In an expanding universe both point A and point B move.

In some frames of reference, maybe. But expansion of space between objects is not the same as those objects moving relative to one another.

[Markus Hanke]

20 hours ago, argo said:

i don't know if its true nor do i have math skill to prove it, but when i look at the evidence from relativity it seems to fit.

The basic problem is that if you only have two isolated points which do not belong to any underlying manifold of at least dimension 1, then it is not possible to establish any kind of meaningful relationship between them. You can consider a point as being a 0-dimensional topological space, but such spaces are fully disconnected.

[MigL]

I know what you mean Jajrussel.
Very hard to read thread.

I get the impression there is a misunderstanding on Argo's part.
A dimension is not a 'place' that can contain points.
Simply put, it is an axis of a co-ordinate system.
And his 'points' don't seem to correlate to space-time events.
I'm not sure what they are.

[mistermack]

44 minutes ago, MigL said:

A dimension is not a 'place' that can contain points.
Simply put, it is an axis of a co-ordinate system.

I don't think that's how most people use the word.

I always thought of dimensions as properties of space time, and the axes of co-ordinate system is just a way of modelling the actual dimensions.

If there is no space time, there is surely no dimensions. One thousand times nothing is still nothing. And pointing 90 degrees from nothing is still pointing at nothing. 

Edited August 18, 2018 by mistermack

[Strange]

52 minutes ago, MigL said:

A dimension is not a 'place' that can contain points.
Simply put, it is an axis of a co-ordinate system.
And his 'points' don't seem to correlate to space-time events.
I'm not sure what they are.

Very succinct. Hopefully, that might help clarify what is meant.

10 minutes ago, mistermack said:

I always thought of dimensions as properties of space time, and the axes of co-ordinate system is just a way of modelling the actual dimensions.

The "actual" dimensions are the just coordinate systems we use to measure time and distance. Whether "space-time" and the associated "dimensions" exist is a question for philosophy. (Or, to put it another way, one that can't be answered.)

11 minutes ago, mistermack said:

If there is no space time, there is surely no dimensions.

Obviously. As the dimensions are what define space-time.

On the other hand, you can have "empty" space-time; dimensions defining space-time but with no matter or energy in it. (This can be useful to test some concepts; for example, certain such empty universes will still expand, and so on.)

[jajrussel]

An Axis is a point singular, and xyz&t each define a single point in space rather than points. Is this what MigL means? When you say.

44 minutes ago, Strange said:

Very succinct. Hopefully, that might help clarify what is meant.

Actually, I would prefer a little more clarity. Pherhaps from Argos point because at one point I thought I was beginning to understand that he was attempting to lable two different points as zero in location and time which can not be. As an observer I can lable both times as zero starting a clock, but then it becomes location point A,0 or location point B,0. I don't know what he meant by 0,0 in relation to point A, and, 0,0 in relation to point B unless he was actually trying to define three difference points were one point is defined as 0,0

I am not that familiar with coordinate systems, but I would think that 0,0 would be the Axis. If that were the case then A,0 and B,0 would seem to define/label, 2 separate events starting at the same time. I think that it would be inaccurate to assume it means two objects occupying the same space in time, yet the way argo asks the question seems to imply that this is what he means. Actually, there is no implication he flat out states the objectional view rather than the one he rhetorically defined which is point A, time 0 and point B, time 0., and their relationship to 0,0. Basically two cars lined up at a starting line. The race hasn't started so they also have a starting time of zero in common. No end point is referenced. When you consider that standard usually implies A as a starting point, and B as a finish point it is no wonder that at least I was confused by what he said.

Now to figure out why some of the replies also seemed confusing.

[mistermack]

2 hours ago, Strange said:

On the other hand, you can have "empty" space-time; dimensions defining space-time but with no matter or energy in it. (This can be useful to test some concepts; for example, certain such empty universes will still expand, and so on.)

Yes. But empty space time isn't nothing. That's what I'm getting at really. The dimensions are dimensions of something, not nothing. 

In a universe of nothing, a metre is the same as a kilometre or a light year. In a universe of empty space time, a kilometre is still a thousand metres. Obviously, a universe of nothing is infinitely nothing, so you can say it doesn't exist. Infinitely nothing is as mysterious as a positive infinity. 

[Strange]

55 minutes ago, mistermack said:

Yes. But empty space time isn't nothing.

What is it then?

55 minutes ago, mistermack said:

The dimensions are dimensions of something, not nothing. 

Are you saying that metres and seconds are made of something? What are they made of? Wood, brass, sealing wax?

56 minutes ago, mistermack said:

In a universe of nothing, a metre is the same as a kilometre or a light year.

I don't know what you base that on. But if you define a metric then that defines how distances are measured.