Time.

[roosh]

 

It is odd how all mechanisms are affected by exactly the same amount though ...

is it the same amount or the same ratio? the answer might lie in the effect gravity has at the sub-atomic or quantum level.

 

it is also odd, however, how the alternative could give rise to reative motion; as was mentioned by someone else, the idea of objects, or particles, as frozen strings, relative motion would not result from that.

 

 

 

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

 

Then discover what these mechanisms are. Physics has a model, and the model works. If you want to replace it, come up with something at least as successful.

I don't doubt the model works, but it is, currently, incompatible with an equally successful theory. From what I have gathered a timeless theory would probably be more compatible with quantum theory.

 

For now though, I'm content just to question it.

Edited November 12, 2013 by roosh

[swansont]

By real I simply mean physical as in a part of the universe. The universe is real, or perhaps it might be more definitive to say that the universe exists; what form it exists might be a separate question.

To say that time is not real is simply to say that it does not make up part of the universe.

 

Then you're in luck with your straw-man. Nobody is claiming time is a physical object. Then again, neither are length, height or width, or many other concepts in physics, like energy, momentum, field lines, etc. They're all concepts that we use as a framework to understand how nature behaves. (That's not the same as claiming to know what nature is.)

 

 

No, but it does require measurement or detection. It can't be demonstrated that time is measureable, unlike the 3 spatial dimensions.

You should Google "clock" and learn about this amazing technology.

 

Although they persist, they only ever exist in the present moment, hence they are not extended in time, or do not have a temporal dimension. There is no circularity in that.

They "don't exist" only because of how you have defined time as not existing. Using that to show that time doesn't exist is circular.

 

The point is that objects are extended in 3 spatial dimensions but not in a temporal one.

 

Which is not true, with the standard definition of time.

 

 

 

It's not to say that the past didn't happen, it's that it no longer exists. We have records and memories of it, but it is no longer physically real, or physically exists - in the manner that it used to exist.

And you need a fourth orthogonal coordinate to refer to them. Thus, time.

 

In order for time to be considered a dimension of the universe, then past and/or future have to physically persist, otherwise there is no dimensionaly quality to time.

No fair making up requirements. A distance between points is still a length, even though the empty space between them need not have anything that physically persists. So that's not a reason that works.

 

 

[roosh]

 

That is dissapointing. Do you think it is too late for me to ask for my money back on this expensive watch?

 

On the other hand, maybe we can measure time. And we can measure the effects of velocity and gravitation on time, exactly as predicted by theory.

You can always ask, or you could accept what the watch actually does and it's usefulness.

 

 

How do we measure time, or more specifically, how is the physical property we call "time" measured by a clock?

[Endy0816]

Without a temporal dimension you'd lack the ability to observe events.

 

 

 

Likening the universe to a frozen tangle of threads is essentially the block universe concept, but it requires the assumptions that both past and future are real, as well as the assumption that time is real/physical and can be measured. Part of the latter assumption requires the assumption that clocks measure this property called "time", even though this cannot be demonstrated.

 

Further, in a universe where the worldlines of objects are like frozen threads i.e. static and unmoving, there would be no relative motion, without some other mechanism to explain it, which in itself would require a further assumption.

 

We can drop all of those assumptions, however, and investigate the concept of time and the idea that clocks measure this property called "time" and realise that nowhere in the process of a clock is something called "time" ever actually measured. In an atomic clock, for example, what is actually measured is the microwave emissions from the electrons of a caseium-133 atom, say; these emissions are measured and counted and this count is used as a standardised unit of comparison. Nowhere is a secondary, physical property, or dimension, measured.

 

 

It would only appear frozen from a 5th dimensional view.

 

Difficult to explain properly but you can't observe an object having a temporal distance of 5 seconds, because you yourself are using time to observe.

 

In theory you could pull it off, but only via sacrificing one of your spacial dimensions or somehow gaining an extra dimension. In either case you still have one dimension you can't traverse freely.

[Strange]

How do we measure time, or more specifically, how is the physical property we call "time" measured by a clock?

 

I think you need to explain first, in what way you think a clock doesn't measure time. What is it measuring? And when we measure the effects of graviational time dilation, what exactly are we measuring?

 

I get the impression you are using the word "time" to refer to something other than the normal sense (in both normal life and phsyics). But I have no idea what that thing is. Perhaps because it doesn't exist.

Edited November 12, 2013 by Strange

[roosh]

Then you're in luck with your straw-man. Nobody is claiming time is a physical object. Then again, neither are length, height or width, or many other concepts in physics, like energy, momentum, field lines, etc. They're all concepts that we use as a framework to understand how nature behaves. (That's not the same as claiming to know what nature is.)

Time is treated as a physical property of the universe, unless physics deals with measuring the non-physical.

 

 

You should Google "clock" and learn about this amazing technology.

I am familiar with it, thanks; I use it on a daily basis. You should, perhaps, question what a clock does, and precisely where in the processes of a clock the physical property called "time" is actually measured, or how a clock demonstrates that the universe has a temporal dimension.

 

They "don't exist" only because of how you have defined time as not existing. Using that to show that time doesn't exist is circular.

I'm sure you will agree that the universe exists, indeed, all that exists is the universe. The question is whether or not time is a property of the universe. Objects appear to be spatially extended and separated, hence the 3 spatial dimensions. Only a single moment ever exists, the present moment, and the configuration of the universe that corresponds to "now". Hence, there is no temporal dimension to the universe.

 

 

Which is not true, with the standard definition of time.

Regardless of how time is defined, unless past and future exist, then the universe does not have a temporal dimension. Defining "time" into existence is circular reasoning and doesn't make it a physical property of the universe.

 

 

And you need a fourth orthogonal coordinate to refer to them. Thus, time.

But the universe is not temporally extended, hence no dimension.

 

 

No fair making up requirements. A distance between points is still a length, even though the empty space between them need not have anything that physically persists. So that's not a reason that works.

A distance between points might be a length, but it is this spatial distance between them that means that the universe has a spatial dimension; the lack of such with regard to time means that the universe doesn't have a temporal dimension.

 

Also, I would question the idea of "empty space" not having anything physical which persists. There has to be something empty space because there cannot be nothing, as in absolute nothing, becuase absolute nothing implies non-existence and the universe is only made up of that which exists.

[Endy0816]

So if there was an object without any spacial dimensions you would expect it not to exist?

[swansont]

Time is treated as a physical property of the universe, unless physics deals with measuring the non-physical.

As I said already, physics deals with many things that are conceptual rather than being physical objects. You earlier said you meant physical in the context of time being a dimension, which is not an object. More like it's a property, which applies to spatial dimensions. In that sense momentum and energy are physical, too.

 

 

I am familiar with it, thanks; I use it on a daily basis. You should, perhaps, question what a clock does, and precisely where in the processes of a clock the physical property called "time" is actually measured, or how a clock demonstrates that the universe has a temporal dimension.

Time is most easily measured by noting that oscillatory systems return to the same state periodically, and we count the oscillations. The phase of the oscillation is what we call time. The phase at any point of the oscillation has a repeatable relation to the earlier phase.

 

I'm sure you will agree that the universe exists, indeed, all that exists is the universe. The question is whether or not time is a property of the universe. Objects appear to be spatially extended and separated, hence the 3 spatial dimensions. Only a single moment ever exists, the present moment, and the configuration of the universe that corresponds to "now". Hence, there is no temporal dimension to the universe.

"Only a single moment ever exists" is an assertion, and can't be used to conclude that only a single moment ever exists. That's why your argument is circular.

 

Regardless of how time is defined, unless past and future exist, then the universe does not have a temporal dimension. Defining "time" into existence is circular reasoning and doesn't make it a physical property of the universe.

 

 

But the universe is not temporally extended, hence no dimension.

The past existed. Are you contending otherwise? I have pictures.

 

 

A distance between points might be a length, but it is this spatial distance between them that means that the universe has a spatial dimension; the lack of such with regard to time means that the universe doesn't have a temporal dimension.

 

Also, I would question the idea of "empty space" not having anything physical which persists. There has to be something empty space because there cannot be nothing, as in absolute nothing, becuase absolute nothing implies non-existence and the universe is only made up of that which exists.

What physically exists to make up length, then? What is length made of?

 

How do we measure time, or more specifically, how is the physical property we call "time" measured by a clock?

 

Time is what a clock measures, by definition. Time is the phase of an oscillation.

 

How is length measured by a ruler?

[Strange]

Defining "time" into existence is circular reasoning

Defining time out of existence by asserting that only "now" exists and therefore the universe has no temporal extent is circular reasoning; specifically, begging the question.

How do you know that only "now" exists? Because the universe is not temporally extended.

How do you know the universe is not termporally extended? Because only "now" exists!

 

A distance between points might be a length, but it is this spatial distance between them that means that the universe has a spatial dimension; the lack of such with regard to time means that the universe doesn't have a temporal dimension.

 

I'm not sure what "the lack of such" refers to. Are you trying to say that time doesn't exist because you can't measure it with a ruler?

 

Of course there is the exact equivalent of events being separated spatially (ie. not being in the same place): it is called not-happening-at the-same-time.

[roosh]

@Endy

Without a temporal dimension you'd lack the ability to observe events.

I don't think we would. We are part of and observe a dynamical system; there is no need for a temporal dimension to observe events. Events occur, some preceding others, we have memory of "past" events and can imagine "future" events, which is what gives rise to our idea of time as a dimension. Just events occuring and the power of observation is necessary to observe events.

 

 

 

It would only appear frozen from a 5th dimensional view.

That doesn't really explain how relative motion can arise from "frozen strings".

 

Difficult to explain properly but you can't observe an object having a temporal distance of 5 seconds, because you yourself are using time to observe.

 

In theory you could pull it off, but only via sacrificing one of your spacial dimensions or somehow gaining an extra dimension. In either case you still have one dimension you can't traverse freely.

Indeed, we don't and we can't (observe objects having a temporal distance).

 

 

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

 

 

 

 

 

I think you need to explain first, in what way you think a clock doesn't measure time. What is it measuring? And when we measure the effects of graviational time dilation, what exactly are we measuring?

 

I get the impression you are using the word "time" to refer to something other than the normal sense (in both normal life and phsyics). But I have no idea what that thing is. Perhaps because it doesn't exist.

What a clock measures, an atomic clock for example, is the mircrowave emissions of electrons of a caesium atom, say, as it changes energy; these microwave emissions are detected and counted and that is what is displayed on the counter. There isn't a secondary, physical, property measured nor is it the measurement of a dimension. What clocks of old measured was the rotation of the earth with respect to the sun.

 

Clocks are essentially just repetitive cycles which are used as a unit of comparison. If we imagine someone who bounces a basketball with amazing regularity, that could be used as a clock, but nowhere in that process is a physical property called "time" measured, nor is it a measure of any dimension. We could express other processes in terms of that bouncing basketball and then compare them to each other. But it doesn't represent a temporal dimension.

 

That is essentially how I refer to "time", as a man-made system of measurement - using naturally occurring processes as a means of comparing different processes in a meaningful manner. We need a standardised unit otherwise we would be comparing apples and oranges.

 

 

 

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

So if there was an object without any spacial dimensions you would expect it not to exist?

if the universe had no spatial dimensions, then I would say that spatial dimensions do not exist.

Edited November 13, 2013 by roosh

[swansont]

 

What a clock measures, an atomic clock for example, is the mircrowave emissions of electrons of a caesium atom, say, as it changes energy; these microwave emissions are detected and counted and that is what is displayed on the counter. There isn't a secondary, physical, property measured nor is it the measurement of a dimension. What clocks of old measured was the rotation of the earth with respect to the sun.

 

Clocks are essentially just repetitive cycles which are used as a unit of comparison. If we imagine someone who bounces a basketball with amazing regularity, that could be used as a clock, but nowhere in that process is a physical property called "time" measured, nor is it a measure of any dimension. We could express other processes in terms of that bouncing basketball and then compare them to each other. But it doesn't represent a temporal dimension.

 

That is essentially how I refer to "time", as a man-made system of measurement - using naturally occurring processes as a means of comparing different processes in a meaningful manner. We need a standardised unit otherwise we would be comparing apples and oranges.

 

 

 

Now answer my question about a how we measure length with a ruler.

[roosh]

 

As I said already, physics deals with many things that are conceptual rather than being physical objects. You earlier said you meant physical in the context of time being a dimension, which is not an object. More like it's a property, which applies to spatial dimensions. In that sense momentum and energy are physical, too.

Spacetime is treated as a physical entity in physics isn't it? Essentially, it's a question of whether or not time is a dimension of the universe. For it to be a dimension of the universe the universe and/or the objects within it must be extended in that temporal dimension; this would require "past" and/or "future" states to exist and persist. This isn't supported by empirical observation.

 

 

Time is most easily measured by noting that oscillatory systems return to the same state periodically, and we count the oscillations. The phase of the oscillation is what we call time. The phase at any point of the oscillation has a repeatable relation to the earlier phase.

Indeed, and these regularly occurring oscillations provide us with a very useful standard unit, in which we can express all other processes; using this standard unit allows us to meaningfully compare different processes to each other. However, as with the processes or objects measured by a clock, the clock itself is not temporally extended; it is, however, spatially extended, that is, extended in 3 spatial dimensions. Hence, time is not a dimension.

 

"Only a single moment ever exists" is an assertion, and can't be used to conclude that only a single moment ever exists. That's why your argument is circular.

The present moment (not to be confused with the present moment in time) is all that is ever empirically observable, so that is the only position that can be supported empirically. For it not to be true, "past" and "future" must exist, and indeed they might, but to arrive at the conclusion that they do one must assume those conclusions, which is where the true circularity lies.

 

It might be more helpful to think in terms of configurations of the universe, or the matter in the universe, instead of "moments" - bcos we tend to think in terms of "moments in time", which is part of the issue. The configuration is constantly changing. Only a single configuration ever exists and that is the configuration that corresponds to the present moment. The "past" configuration has changed and so, no longer exists; the "future" configuration doesn't exist yet.

 

 

The past existed. Are you contending otherwise? I have pictures.

We are in complete agreement on this; the past existed, past tense, but it no longer exists.

 

 

What physically exists to make up length, then? What is length made of?

Again, it might be more helpful to talk in terms of dimensions; objects are extended in 3 spatial dimensions and objects are spatially separated in 3 spatial dimensions; objects and events are not extended temporally and are not separated in a temporal dimension, because the past has ceased to exist and the future doesn't exist yet; only the present configuration exists, hence no temporal dimension.

 

 

Time is what a clock measures, by definition. Time is the phase of an oscillation.

I agree, but I would say that "time" is a system of measurement (not necessarily like the systems of measurement used to measure the spatial dimensions of an object, or the spatial separation of objects) and the phase of an oscillation provides a useful standardised unit which we can use to compare different systems/processes, in a meaningful manner. The phase of an oscillation doesn't, however, demonstrate a temporal dimension.

 

 

How is length measured by a ruler?

The ruler is placed beside the object it is measuring, for arguments sake, but the ruler is also spatially extended. A clock is just a counter which is not temporally extended, just like the object or system it measures. Hence, no temporal dimension.

 

 

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

 

 

p.s. does anyone know how to stop individual replies from getting lumped in together?

Edited November 13, 2013 by roosh

[Strange]

 

Clocks are essentially just repetitive cycles which are used as a unit of comparison. If we imagine someone who bounces a basketball with amazing regularity, that could be used as a clock, but nowhere in that process is a physical property called "time" measured, nor is it a measure of any dimension. We could express other processes in terms of that bouncing basketball and then compare them to each other.

 

Yes, that regularity is what is technically known as "time" (I realise that might be a tricky concept).

 

So, having defined time, you say it doesn't exists. Hmmm....

 

 

But it doesn't represent a temporal dimension.

 

And yet, when used in that way it provides us with a remarkably successful (arguably, the most successful) model of the universe. Not bad for something that doesn't exist.

 

 

 

if the universe had no spatial dimensions, then I would say that spatial dimensions do not exist.

 

You weren't asked if the universe had no spatial dimensions. Do you want to answer the question asked? (I think it is a good one.)

 

I think this sort of petty hair-splitting over the meanings of words like "time", "exist", etc belongs more in philosophy than physics. In physics, time is a dimension. You might not like that but ... <shrug> ... I don't suppose either physicists or the universe care that much.

I am curious why, in another thread, you don't seem to object to what you call the "block universe" (1) which appears to rely on time existing (2). But in this thread you claim that time doesn't exist. Are these views inconsistent?

 

(1) not a term I have come across before, but it seems to be pretty much equivalent to "space-time manifold"

(2) whatever "existing" means

 

A clock is just a counter which is not temporally extended

 

You keep making this assertion: "X is not temporally extended". You have yet to provide any support for it.

 

A clock, very obviously, is temporally extended because it keeps making those regular cyclic chnages you used to define time. It made them in the past and will continue to make them in the future. That is what temporally extended means.

Edited November 13, 2013 by Strange

[Endy0816]

 

@Endy

I don't think we would. We are part of and observe a dynamical system; there is no need for a temporal dimension to observe events. Events occur, some preceding others, we have memory of "past" events and can imagine "future" events, which is what gives rise to our idea of time as a dimension. Just events occuring and the power of observation is necessary to observe events.

 

 

 

That doesn't really explain how relative motion can arise from "frozen strings".

 

Indeed, we don't and we can't (observe objects having a temporal distance).

 

 

 

 

It is a case of perception vs reality.

 

If we rendered instances of a "2D" flatland next to each other you could walk along and see past, present and future for the little world. Something existing within the world would observe relative motion. You outside of it observe frozen frames.

 

Their time is your distance.

 

 

if the universe had no spatial dimensions, then I would say that spatial dimensions do not exist.

 

 

 

I was mainly getting at black holes. Spacial expansion is another one.

 

The dimensions exist on their own terms, best not get too attached.

[roosh]

So, having defined time, you say it doesn't exists. Hmmm....

Not as a dimension anyway.

 

 

And yet, when used in that way it provides us with a remarkably successful (arguably, the most successful) model of the universe. Not bad for something that doesn't exist.

A remarkably successful model which is, at present, not reconciled with the other, arguably, most successful physical theory. From what I can gather, that reconciliation could be made easier if relativity had a more absolute notion of time. Incidentally, non-existent time is very similar to absolute time.

 

"Time" wouldn't be used any differently, clocks would still be employed. The idea of reciprocal (two-way) time dilation would, however, be removed, something for which there is no empirical evidence of - there is only evidence of one-way time dilation.

 

 

You weren't asked if the universe had no spatial dimensions. Do you want to answer the question asked? (I think it is a good one.)

The question, of whether or not objects without spatial dimensions exist, was not representative of the issue. It would have been more representative to ask, if objects didn't have spatial dimensions would I say spatial dimensions didn't exist. If the neither the universe nor the objects within it were not spatially extended, then I would say that spatial dimensions do not exist.

 

 

I think this sort of petty hair-splitting over the meanings of words like "time", "exist", etc belongs more in philosophy than physics. In physics, time is a dimension. You might not like that but ... <shrug> ... I don't suppose either physicists or the universe care that much.

Questions such as, what is time in physics is a question of physics; the word "exist" can prove to be a stumbling block but we can circumvent that by asking if time is actually a dimension, as opposed to questioning the existence of time. By demonstrating that neither the universe, nor the objects within it, are temporally extended we can highlight that "time" does not have any dimensional quality.

 

While it might be considered a dimension in contemporary physics, that doesn't necessarily mean that it is, just as Newtons contemporaries believed that time was absolute but our contemporaries no longer accept that.

 

It doesn't really bother me that much tbh, it's just something I have an interest in and enjoy discussing.

[swansont]

We are in complete agreement on this; the past existed, past tense, but it no longer exists.

 

 

You can't have or talk about a past without time.

 

 

Again, it might be more helpful to talk in terms of dimensions; objects are extended in 3 spatial dimensions and objects are spatially separated in 3 spatial dimensions; objects and events are not extended temporally and are not separated in a temporal dimension, because the past has ceased to exist and the future doesn't exist yet; only the present configuration exists, hence no temporal dimension.

All one can conclude from this is that the temporal dimension doesn't behave exactly the same as the spatial dimensions. But we already know this. Things exist from one moment to the next. That's how "temporal extension" works. You seem to be trying to narrow this and claim that because it doesn't work in a certain way that it doesn't exist, yet you need to have a fourth dimension, because three does not account for the phenomena we observe. Things change, the past is not an illusion, and there are things about the future that are predictable.

 

 

 

I agree, but I would say that "time" is a system of measurement (not necessarily like the systems of measurement used to measure the spatial dimensions of an object, or the spatial separation of objects) and the phase of an oscillation provides a useful standardised unit which we can use to compare different systems/processes, in a meaningful manner. The phase of an oscillation doesn't, however, demonstrate a temporal dimension.

The phase changes. You can't account for that with only three dimensions.

 

The ruler is placed beside the object it is measuring, for arguments sake, but the ruler is also spatially extended. A clock is just a counter which is not temporally extended, just like the object or system it measures. Hence, no temporal dimension.

You compare it to a calibrated standard, which is what you are doing with a clock; the phase is calibrated to the time. Circular reasoning aside.

 

p.s. does anyone know how to stop individual replies from getting lumped in together?

It happens automatically with the board software. Which is one reason why one is encourage to learn how to use the quote tags with attribution. (quote name="whatever", etc. which you can copy/paste in the editor if you're in the correct edit mode)

[Strange]

A remarkably successful model which is, at present, not reconciled with the other, arguably, most successful physical theory. From what I can gather, that reconciliation could be made easier if relativity had a more absolute notion of time.

 

Citation needed.

 

 

"Time" wouldn't be used any differently, clocks would still be employed. The idea of reciprocal (two-way) time dilation would, however, be removed, something for which there is no empirical evidence of - there is only evidence of one-way time dilation.

 

You can't have one without the other.

 

 

The question, of whether or not objects without spatial dimensions exist, was not representative of the issue. It would have been more representative to ask, if objects didn't have spatial dimensions would I say spatial dimensions didn't exist. If the neither the universe nor the objects within it were not spatially extended, then I would say that spatial dimensions do not exist.

Why not just answer the question? It would have taken less words than waffling about why you don't want to answer it,.

 

 

Questions such as, what is time in physics is a question of physics; the word "exist" can prove to be a stumbling block but we can circumvent that by asking if time is actually a dimension, as opposed to questioning the existence of time. By demonstrating that neither the universe, nor the objects within it, are temporally extended we can highlight that "time" does not have any dimensional quality.

 

a) You haven't demonstrated anything; you have just asserted it.

 

b) We have evidence (a working theory) that time is a dimension

 

c) We have no evidence (beyond your assertions) that time is not a dimension

 

d) Hoping that a future theory might change that is just wishful thinking, not science or rational argument.

 

If it is a subject you enjoy thinking about and discussing, I would have thought you might have come up with something other than an assertion.

Edited November 13, 2013 by Strange

[roosh]

I am curious why, in another thread, you don't seem to object to what you call the "block universe" (1) which appears to rely on time existing (2). But in this thread you claim that time doesn't exist. Are these views inconsistent?

 

(1) not a term I have come across before, but it seems to be pretty much equivalent to "space-time manifold"

(2) whatever "existing" means

The purpose of the other thread was to see what the generally accepted status of the "block universe" is, within the field of physics, not to question it's validity. The reason for it was bcos I thought it was a widely accepted concept, due to it's prominence in the mainstream, pop-science documentaries, and bcos physicists such as prof. Greene seem to champion it.

 

Personally I don't agree with it, but as I said, that wasn't the purpose of the thread.

 

 

The term "exist" (and it's variants) tends to cause a bit of consternation, but it needen't, bcos we can ask a simple question: is there existence? The answer is unquestionably yes; that we can pose the question is verification of that. It sounds like a philosophical question but it isn't really. Existence is just a label we apply to our experience of the universe.

 

 

You keep making this assertion: "X is not temporally extended". You have yet to provide any support for it.

We only ever experience the present moment; empirical observation is only possible in the present moment. We can't observe "the past", nor can we observe "the future". For an object, X, to be temoporally extended it's "past" and "future" states would have to be physical. The lack of empirical evidence that this is the case means that there is no empirical support for a temporal dimension.

 

 

A clock, very obviously, is temporally extended because it keeps making those regular cyclic chnages you used to define time. It made them in the past and will continue to make them in the future. That is what temporally extended means.

Indeed, it made them in "the past", but "the past" is no longer exists, and "the future" doesn't exist - "past" and "future" are not physical - so the clock is not extended temporally; it only ever operates in the present moment.

[Strange]

 

We only ever experience the present moment

 

Ah, I see where you are coming from now. You are basing your belief on the vagaries of human perception rather than objective evidence. That makes sense (as in, that explain why it is a personal belief rather than science).

 

Not that I think it is relevant, but it seems fairly clear that even the human perception of a single "now" is an illusion.

 

 

Indeed, it made them in "the past", but "the past" is no longer exists, and "the future" doesn't exist - "past" and "future" are not physical - so the clock is not extended temporally; it only ever operates in the present moment.

 

No, you only perceive it in the present, which isn't the same thing at all. Your use of words like past and future indicates that, really, you know that time exists (even if you try and pretend it doesn't by putting them in scare quotes). Give it up: you've been rumbled.

 

 

Existence is just a label we apply to our experience of the universe.

 

That is a very limited definition of existence. There are all sorts of things we consider to exist that we have no direct experience of.

 

All of which explains why science relies on objective tests rather than personal opinions, which can be so flawed.

Edited November 15, 2013 by Strange

[decraig]

There are no decidable propositions, so the question whether or not 'time' is an illusion is also undecidable.

 

The usual assumption in the study of physics is that there exists some sort of objective reality, and go on from there.

 

If we assume that 'time' is something that is measured with a clock using some particular procedure then it immediately follows that 'time' does not exist. The past existed. The future might exist. But if we say time exists then everything happens all at once.

[swansont]

 

If we assume that 'time' is something that is measured with a clock using some particular procedure then it immediately follows that 'time' does not exist. The past existed. The future might exist. But if we say time exists then everything happens all at once.

 

I don't see how that follows, given that this is pretty much the opposite of what time implies. It's like saying if the three spatial dimensions exist, then all matter must exist at a single point.

[decraig]

 

I don't see how that follows, given that this is pretty much the opposite of what time implies. It's like saying if the three spatial dimensions exist, then all matter must exist at a single point.

 

That is something I've also considered, but the meaning is different. Something displaced at a distance can still be existent.

 

Our language(s) in it's verb tense has to be used carefully. You can point at a Minkowski diagram and say "here is the present", "below this line is the past", and similar statements. It serves well as a model of space-time. Equally true, the verb tense used to talk about the Minkowski diagram is not the correct verb tense to use for space-time.

 

Some insightful guy--I don't know who--once said "the map is not the territory".

 

One book of Brian Greene goes a long way in trying to convince us that that space-time is an existent whole. It's certainly good to think four dimensionally, but at the same time, it's simply not true. The repercussions from this book seem to have adversely tainted the accepted language.

[roosh]

It is a case of perception vs reality.

 

If we rendered instances of a "2D" flatland next to each other you could walk along and see past, present and future for the little world. Something existing within the world would observe relative motion. You outside of it observe frozen frames.

 

Their time is your distance.

That's not saying much though, it's just saying that we don't perceive the universe as frozen, but we would if we were looking at things from outside. It doesn't explain how relative motion can arise from "frozen strings", because it shouldn't, without some additional mechanism to explain it.

 

 

 

 

 

 

I was mainly getting at black holes. Spacial expansion is another one.

 

The dimensions exist on their own terms, best not get too attached.

I haven't really given much thought to it tbh, but as mentioned I don't think it represents the issue being discussed.

[roosh]

You can't have or talk about a past without time.

And you can't have a talk about unicorns without referring to a horse-like creature with a single horn protruding from it's forehead, but that doesn't make them real.

 

We could, potentially, have a talk about a "past" without reference to "time" though, if we investigate what a "past" actually is; when we do, we can see that it is just a former configuration of a previous present moment. "The past" only exists as a mental construct, or as a concept; it is a memory or a set of records which corresponds to the present moment before it changed to the current configuration. Even when our predictions of "future" configurations materialise, they will do so in the present moment. It is always the present moment, and it always will be - again, not to be confused with the present moment in time.

 

 

 

All one can conclude from this is that the temporal dimension doesn't behave exactly the same as the spatial dimensions. But we already know this. Things exist from one moment to the next. That's how "temporal extension" works. You seem to be trying to narrow this and claim that because it doesn't work in a certain way that it doesn't exist, yet you need to have a fourth dimension, because three does not account for the phenomena we observe. Things change, the past is not an illusion, and there are things about the future that are predictable.

I won't question what you mean by the term "exist", because I think we all have an understanding of it, even if the nature of that existence is open to question.

 

To be temporally extended, the "past" and "future" states of an object or system must exist, otherwise it isn't extended temporally. If objects exist from one moment to the next, but the previous moment ceases to exist as soon as the next one arises, then there is no temporal extension. Given that there is no empirical evidence to support that either past or future states exist, then the idea of time as a dimension, or that objects are temporally extended is unempirical.

 

Again, the idea of "moments" might be a bit misleading, not least because we associate them with "time"; it might be more helpful to think in terms of configurations of matter. When a configuration of matter changes, unless the "past" configuration persists in the overall structure of the universe, then the configuration of matter is not temporally extended.

 

We don't need a 4th dimension to account for what we observe, not least because we don't observe a 4th dimension, we assume it. Systems in the universe, and the universe itself, undergoes change; there is no need for a 4th dimension to account for this. We can acknowledge that the matter in the universe used to be configured in a certain way, but has subsequently changed and is continuously changing. Only if we assume that the "past" and/or "future" configuration exists do we arrive at the conclusion that the universe is temporally extended. That's not to say that "the past" is an illusion, the "past" was real, but it's not anymore, and the "future" isn't real. We can't make empirical observations of either, so the idea of the universe being temporally extended, or having time as a dimension is unempirical.

 

 

 

 

The phase changes. You can't account for that with only three dimensions.

How does a change in phase demonstrate that it is temoporally extended? Only if the "past" and/or "future" states exist in the overall structure of the universe can it be said to be temporally extended; and there is no empirical evidence to support the contention that they do.

 

 

 

You compare it to a calibrated standard, which is what you are doing with a clock; the phase is calibrated to the time. Circular reasoning aside.

The conclusion that time is a dimension can only be arrived at by assuming the conclusions that "past" and or "future" are physically real, that they exist, or that they make up part of the overall structure of the universe, however you wish to phrase it.

 

 

 

It happens automatically with the board software. Which is one reason why one is encourage to learn how to use the quote tags with attribution. (quote name="whatever", etc. which you can copy/paste in the editor if you're in the correct edit mode)

ah, cheers. I think I have it now.

 

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Edited November 21, 2013 by roosh

[swansont]

And you can't have a talk about unicorns without referring to a horse-like creature with a single horn protruding from it's forehead, but that doesn't make them real.

 

Bad analogy. Horses are physical objects and unicorns don't exist as physical objects, but since nobody is claiming that time is a physical object, this is nothing more than a straw man you've knocked down.

 

We could, potentially, have a talk about a "past" without reference to "time" though, if we investigate what a "past" actually is; when we do, we can see that it is just a former configuration of a previous present moment. "The past" only exists as a mental construct, or as a concept; it is a memory or a set of records which corresponds to the present moment before it changed to the current configuration. Even when our predictions of "future" configurations materialise, they will do so in the present moment. It is always the present moment, and it always will be - again, not to be confused with the present moment in time.

Length only exists as a mental construct, too, but that doesn't seem to be a problem. You can only be in one place at a time — you can only be "here", you can never be "there". The same semantic games you play with time can also be played with space. Which is why such games are useless.

 

The thing is, physics doesn't bother with the semantic games. It doesn't discuss here, there, now or anything like that.

 

I won't question what you mean by the term "exist", because I think we all have an understanding of it, even if the nature of that existence is open to question.

 

To be temporally extended, the "past" and "future" states of an object or system must exist, otherwise it isn't extended temporally. If objects exist from one moment to the next, but the previous moment ceases to exist as soon as the next one arises, then there is no temporal extension. Given that there is no empirical evidence to support that either past or future states exist, then the idea of time as a dimension, or that objects are temporally extended is unempirical.

And this is the point where I once again ask how you can describe non-static systems with only three variables. Which I expect you once again to dodge.

 

 

Again, the idea of "moments" might be a bit misleading, not least because we associate them with "time"; it might be more helpful to think in terms of configurations of matter. When a configuration of matter changes, unless the "past" configuration persists in the overall structure of the universe, then the configuration of matter is not temporally extended.

 

We don't need a 4th dimension to account for what we observe, not least because we don't observe a 4th dimension, we assume it. Systems in the universe, and the universe itself, undergoes change; there is no need for a 4th dimension to account for this. We can acknowledge that the matter in the universe used to be configured in a certain way, but has subsequently changed and is continuously changing. Only if we assume that the "past" and/or "future" configuration exists do we arrive at the conclusion that the universe is temporally extended. That's not to say that "the past" is an illusion, the "past" was real, but it's not anymore, and the "future" isn't real. We can't make empirical observations of either, so the idea of the universe being temporally extended, or having time as a dimension is unempirical.

That implies if you're sitting in a chair at a desk you can never be anywhere else but sitting in a chair at that desk. If a pick a coordinate system here is a unique (x,y,z) that describes your state. Nobody can ever observe you at a different set of coordinates or sit in that chair, because you occupy it.

 

Which, of course, is BS. As is the claim that you can't "observe" the past. Your ability to observe the past is limited to data that was recorded. IOW, photos don't go blank.

 

 

How does a change in phase demonstrate that it is temoporally extended? Only if the "past" and/or "future" states exist in the overall structure of the universe can it be said to be temporally extended; and there is no empirical evidence to support the contention that they do.

 

The conclusion that time is a dimension can only be arrived at by assuming the conclusions that "past" and or "future" are physically real, that they exist, or that they make up part of the overall structure of the universe, however you wish to phrase it.

No, the conclusion that time is not a dimension is only true for your straw man version of time. And I don't disagree with that. Your version of time doesn't exist, but your version is not what everyone else is using.