Question on Spacetime

roosh

antiselfdual wrote: »

What property of electron emissions is being measured?

is it the microwave emissions as they change energy levels?

roosh

Morbert wrote: »

If we suppose that a specific interaction between the clock's mechanism and its environment is responsible for slower "ticking", then that effect depends specifically on that interaction. Introducing a clock with a different mechanism (say photons and mirrors), would invoke a different interaction, and hence a different effect. This means that, if physical interactions are responsible for time dilation, there is no reason why clocks which employ different mechanisms should incur the same amount of time dilation, as they are both being affected by their environment differently. Yet time dilation is independent of what clock we use. It's a massive coincidence if interactions between an environment and different clocks slow them all down to the same extent. Instead, it implies an underlying structure to what we call the passage of time.



Everyone would agree that time is not directly measured by clocks. This is what Prof. Fink meant when he said time is not an observable. But if time is assumed to be a dimension of spacetime, then clocks quantitatively indicate distance "dt".

OK, but if time is assumed to be a dimension of spacetime, then it doesn't really have any inherent existence, it is a manmade concept.

Turtwig

mangaroosh wrote: »

OK, but if time is assumed to be a dimension of spacetime, then it doesn't really have any inherent existence, it is a manmade concept.

Sorry now magaroosh, but what exactly isn't a man made concept?

antiselfdual

mangaroosh wrote: »

is it the microwave emissions as they change energy levels?

Well no - so what I was trying to get at was that you're not just measuring "microwave emissions" - you observe microwave emissions, but measurement refers to recording some property of the emission. In this case you're observing distinct occurences of microwave emissions at different moments in time and taking those moments as a measurement of time (or else observing distinct occurences of microwave emissions and taking the interval between those occurences as signifying that time has passed and using that as a time measurement). If you argue that there is no such thing as time then what are we actually measuring?

It's similar to saying that if say you're using a pendulum to measure time, then no you're not measuring time, you're just measuring the position of a pendulum. But if you say there's no such thing as time it makes no sense as to what you're measuring the position of the pendulum against. You can't say that the pendulum is at its highest point, and then at the other highest point, because the "then" implies that there has been an interval in something we choose to call time (and if I keep thinking along these lines I get confused about what the argument is actually about so I can't tell if what I'm trying to say makes sense).

What Morbert said at the end of the last page

Morbert wrote: »

Everyone would agree that time is not directly measured by clocks. This is what Prof. Fink meant when he said time is not an observable. But if time is assumed to be a dimension of spacetime, then clocks quantitatively indicate distance "dt".

is probably the most succint and elegant answer about what time is you're probably going to get.

Morbert

mangaroosh wrote: »

OK, but if time is assumed to be a dimension of spacetime, then it doesn't really have any inherent existence, it is a manmade concept.

Your conclusion (time has no inherent existence) doesn't follow from the assumption (time is a dimension of spacetime).

Kevster

Morbert wrote: »

Everyone would agree that time is not directly measured by clocks. This is what Prof. Fink meant when he said time is not an observable. But if time is assumed to be a dimension of spacetime, then clocks quantitatively indicate distance "dt".

Eureka!... ...I now get it just from these 4 lines. I'm not being sarcastic here either, because I genuinely have now grasped what we've been talking about. I won't be putting up my silly argument any longer

mangaroosh, your reply to my post really helped too.

Cheers guys.

Kevin

Morbert

del88 wrote: »

So everyone is in their own now and if i was to meet you then we woulds share a now for now and then go our seprate ways.....then if we're all in our own now that would mean time is actually running backwards just like a pole stuck in the bed of a river with the water flowing past.....we're the pole and time is the river.....(this is going to get interesting)

Simultaneity is related to your velocity. Special relativity says that if we are standing still with respect to one another, we would share the same "now". However, if we have different velocities with respect to one another, then our spacetime "axes" will be contracted with respct to one another.



(This figure shows two sets of axes, with the blue set contracted. Notice how a single moment in the blue axes [say, the blue "space line" running through the origin] actually extends across several values of the white time axis).

A moment/"now" in one set of axes is smeared across several time values in another axes. No travelling backwards needs to be supposed.

[edit]-Urg, after reading this again and I'm not being terribly clear.

roosh

antiselfdual wrote: »

Well no - so what I was trying to get at was that you're not just measuring "microwave emissions" - you observe microwave emissions, but measurement refers to recording some property of the emission. In this case you're observing distinct occurences of microwave emissions at different moments in time and taking those moments as a measurement of time (or else observing distinct occurences of microwave emissions and taking the interval between those occurences as signifying that time has passed and using that as a time measurement). If you argue that there is no such thing as time then what are we actually measuring?

the emboldened above is circular reasoning, time is assumed to exist and then somethingis taken as a measurement of it

antiselfdual wrote: »

It's similar to saying that if say you're using a pendulum to measure time, then no you're not measuring time, you're just measuring the position of a pendulum. But if you say there's no such thing as time it makes no sense as to what you're measuring the position of the pendulum against. You can't say that the pendulum is at its highest point, and then at the other highest point, because the "then" implies that there has been an interval in something we choose to call time (and if I keep thinking along these lines I get confused about what the argument is actually about so I can't tell if what I'm trying to say makes sense).

No need to worry, you are making perfect sense.

This example may be easier to explain. With regard to the pendulum, what is being measured is the position of the pendulum with regard to itself.

The "then" that is referred to is something which no longer exists in reality, it is only a memory of the location of the pendulum. it might be helpful to imagine the pendulum. There is only one pendulum, and it only exists in one place "at a time".

So if the details of the pendulum are recorded, or its position is noted, as soon as it moves from that position, the original position (for which we have the details) no longer exists in reality, so what is being compared is non-reality to reality (or our perception of reality).

It is the measurement of the observed change that gives rise to the conept of time. In a similar way the metric system was arrived at by taking an imaginary line around the earth and dividing it into uniform parts.
What Morbert said at the end of the last page

roosh

Morbert wrote: »

Your conclusion (time has no inherent existence) doesn't follow from the assumption (time is a dimension of spacetime).

my bad, it may not be derived from that assumption, but that is not how it was originally derived.

EDIT: that is the assumption however that is being questioned

Morbert

mangaroosh wrote: »

my bad, it may not be derived from that assumption, but that is not how it was originally derived.

EDIT: that is the assumption however that is being questioned

It's fine to question the assmuption. But you seem to have concluded that the assumption is false. Time could very well be as real as length or height.

roosh

Morbert wrote: »

It's fine to question the assmuption. But you seem to have concluded that the assumption is false. Time could very well be as real as length or height.

it is only through questioning the assumption that the conclusion has been reached.

examination of the evidence would suggest, that time does not exist.

Turtwig

mangaroosh wrote: »

it is only through questioning the assumption that the conclusion has been reached.

examination of the evidence would suggest, that time does not exist.

So if we assume "time's" existence is false (which it may well be) have you got any practical way of using that assumption?

Morbert

mangaroosh wrote: »

it is only through questioning the assumption that the conclusion has been reached.

examination of the evidence would suggest, that time does not exist.

How would examination of the evidence suggest that time does not exist? Relativity, which has a vast amount of experimental evidence, assumes that time exists as a dimension of spacetime.

"The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality." –Hermann Minkowski, 1908

Effective formalisms, such as the stuff Julian Barbour is working on, is interesting but not yet there, and not as developed as other Quantum Gravity approaches that do not remove time.

roosh

Morbert wrote: »

How would examination of the evidence suggest that time does not exist? Relativity, which has a vast amount of experimental evidence, assumes that time exists as a dimension of spacetime.

"The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality." –Hermann Minkowski, 1908

Effective formalisms, such as the stuff Julian Barbour is working on, is interesting but not yet there, and not as developed as other Quantum Gravity approaches that do not remove time.

Unfortunately I haven't read Barbour's book yet (think it's waiting at home for me), but whether or not there has been an accurate formalism within the world of science, has no bearing on whether or not time exists.

One would presume that before an accurate formalism can be formulated, that it must first be realised that time doesn't exist.

As mentioned above, relativity assumes that time exists as a dimension of spacetime. This is why the assumption is questioned.

Examining the evidence shows that clocks don't actually measure a phenomenon called time.

On this basis, what evidence is there for the existence of time?

roosh

Malty_T wrote: »

So if we assume "time's" existence is false (which it may well be) have you got any practical way of using that assumption?

That would be a different discussion, although I'm sure there would be plenty of applications for the truth (if it is indeed true - which it is).

Podge_irl

mangaroosh wrote: »

Examining the evidence shows that clocks don't actually measure a phenomenon called time.

On this basis, what evidence is there for the existence of time?

QFT is 99.99999% accurate, and time being a dimension much like space (though with opposite signature) is inherent in QFT. It is, by far, the most successful theory we possess today.

If you want to suggest there is no such thing as time then feel free, but you're going to have to come up with a formalism more accurate than QFT which doesn't naturally encode a time dimension before I take you seriously.

roosh

Podge_irl wrote: »

QFT is 99.99999% accurate, and time being a dimension much like space (though with opposite signature) is inherent in QFT. It is, by far, the most successful theory we possess today.

If you want to suggest there is no such thing as time then feel free, but you're going to have to come up with a formalism more accurate than QFT which doesn't naturally encode a time dimension before I take you seriously.

that is a false dilemma. The existence of time is not dependent on whether a formalism more accurate than QFT is devised, just as the orbit of the earth around the sun was not dependent on an accurate theory.

as mentioned, the issue is a reversal of cause and effect, to the extent that any measurements taken would remain, however what exactly is being measured is the assumption that needs to be questioned

EDIT: apologies, the above obviously isn't a false dilemma, because whether or not you take the contention seriously, is up to yourself.

the false dilemma would be suggesting that a new theory is required, accounting for old results, before time can be deemed to be non-existent.

As mentioned however, the issue is that time is taken to be something real, as opposed to a manmade measuring system (ala the metric system). This means that the predictions will not change as such, as the measurement system would remain, and therefore any experiment results would not change, so no new theory would be required to interpret the results.

What would be required is to change the assumption upon which the theory is based.


Of course, you don't have to take anybody's word for it, simply question the assumption yourself.


The issue however, is that in all of these theories, time is assumed to exist, but not expressly tested. It is assumed that a clock measures time, which is effectively circular reasoning (assume that time exists and that a clock measures it).

Morbert

mangaroosh wrote: »

that is a false dilemma. The existence of time is not dependent on whether a formalism more accurate than QFT is devised, just as the orbit of the earth around the sun was not dependent on an accurate theory.

as mentioned, the issue is a reversal of cause and effect, to the extent that any measurements taken would remain, however what exactly is being measured is the assumption that needs to be questioned

I still don't think you understand what we are saying. In three dimensional space, there are (obviously) three directions (call them x,y, and z). The distance between points is determined by a "metric" that looks like pythagoras's theorem:

ds^2 = dx^2 + dy^z + dz^2

This says if you want the distance "ds" between two points, the square of that distance is equal to distance in the x direction squared plus distance in the y direction squared plus distance in the z direction squared.

Now consider a four dimensional space where

ds^2 = dx^2 + dy^2 + dz^2 + dt^2

We have four spatial directions here. Now what's strange is that, if the signature of one of these directions is reversed, it behaves exactly like a temporal direction. The local "metric" of spacetime is

ds^2 = dx^2 + dy^2 + dz^2 - c^2dt^2

Now, electromagnetism tells us that the speed of light is the same for all observers, so scientists look at the group of spacetime transformations that preserve the speed of light. When they do this, not only can they predict time dilation effects , they can also use this spacetime structure to predict and understand particle interactions. From an elegant spacetime structure comes a wide range of predictable physical phenomena. The existence of time is therefore inferred.

Now you are saying "oh QFT and relativity are only effective theories, and that we have cause and effect reversed, and that spacetime doesn't exist", which is all well and good. But you have to produce an argument as to why we should accept that. Because, all things being equal, the existence of a spacetime structure is a much simpler and more elegant explanation than the existence of a plethora of new but unobserved and unexplained physical effects and dynamics that all happen to come together to create the appearance of spacetime.

roosh

Morbert wrote: »

I still don't think you understand what we are saying. In three dimensional space, there are (obviously) three directions (call them x,y, and z). The distance between points is determined by a "metric" that looks like pythagoras's theorem:

ds^2 = dx^2 + dy^z + dz^2

This says if you want the distance "ds" between two points, the square of that distance is equal to distance in the x direction squared plus distance in the y direction squared plus distance in the z direction squared.

Now consider a four dimensional space where

ds^2 = dx^2 + dy^2 + dz^2 + dt^2

We have four spatial directions here. Now what's strange is that, if the signature of one of these directions is reversed, it behaves exactly like a temporal direction. The local "metric" of spacetime is

ds^2 = dx^2 + dy^2 + dz^2 - c^2dt^2

I won't challenge the above, because I don't have the knowledge required to do so.

Morbert wrote: »

Now, electromagnetism tells us that the speed of light is the same for all observers, so scientists look at the group of spacetime transformations that preserve the speed of light. When they do this, not only can they predict time dilation effects , they can also use this spacetime structure to predict and understand particle interactions From an elegant spacetime structure comes a wide range of predictable physical phenomena. The existence of time is therefore inferred.

the thing is, time is not actually inferred, it is assumed to exist at the outset, and the subsequent inference is based on this assumption.

time is not tested in any of the theories, it is assumed to exist, and it is assumed that a clock measures time. This is a self-contained system, which breaks down when the question is asked, does a clock actually measure time.

Morbert wrote: »

Now you are saying "oh QFT and relativity are only effective theories, and that we have cause and effect reversed, and that spacetime doesn't exist", which is all well and good. But you have to produce an argument as to why we should accept that. Because, all things being equal, the existence of a spacetime structure is a much simpler and more elegant explanation than the existence of a plethora of new but unobserved and unexplained physical effects and dynamics that all happen to come together to create the appearance of spacetime.

indeed, and the argument is that a clock does not actually measure a phenomenon called time, rather, a clock is the "measuring tape", of the measurement system, known as time.

the thing is that the experiment results would not be altered, because the measurement system would remain. It is the assumptions of the theory that would need to be changed.

as for spacetime being simple and elegant, that has no bearing on the existence, or otherwise, of time.

Morbert

mangaroosh wrote: »

the thing is, time is not actually inferred, it is assumed to exist at the outset, and the subsequent inference is based on this assumption.

time is not tested in any of the theories, it is assumed to exist, and it is assumed that a clock measures time. This is a self-contained system, which breaks down when the question is asked, does a clock actually measure time.

Time is very much inferred. Yes, Quantum Field Theory and Relativity assume time exists as a facet of spacetime. Without this assumpion (i.e. If time did not exist as a part of spacetime), then these theories would not be formulated. The inferrence that these assumptions are true stems from the fact that these theories are not only consistent with a set of observations, but have predicted and been affirmed by new observations.

indeed, and the argument is that a clock does not actually measure a phenomenon called time, rather, a clock is the "measuring tape", of the measurement system, known as time.

Do you have the same objections to the idea of spatial position?

the thing is that the experiment results would not be altered, because the measurement system would remain. It is the assumptions of the theory that would need to be changed.

This is why I presented the stuff on metrics. The theories do not rely on time in a superficial way. Remember that, according to QFT and Relativity, time not only exists, but exhibits geometrical properties and interrelationships with space. If you reduce time to a tape measurer, you lose these connections, and the entire theory falls apart.

as for spacetime being simple and elegant, that has no bearing on the existence, or otherwise, of time.

The thing is, if we do not assume spacetime exists, then we must assume a bunch of unobserved and unexplained hidden physical processes exist. These unobserved processes would draw the same criticism have against time, only much more so.

onq

mangaroosh wrote: »

<snippage has occurred>
I suppose what I am trying to get at, is, if time is unbundled from spacetime, would the equations still show us to be in an expanding universe?

How could any expansion occur without a time element?

ONQ.

Professor_Fink

mangaroosh wrote: »

The issue however, is that in all of these theories, time is assumed to exist, but not expressly tested. It is assumed that a clock measures time, which is effectively circular reasoning (assume that time exists and that a clock measures it).

This is getting silly, particularly since you have now asserted in a previous post that time does not exist. I can no more prove that time exists than that I exist, but given the working assumption that I do in fact exist, as I perceive myself to ("cogito, ergo sum" and all that), then time exists. We all experience a changing universe (in fact "cogito" implies a time ordered process), and we label the variable with which we parameterise this change "time". To say time does not exist is to say that we do not have this experience, which is essentially saying that we do not exist. But, since we're here to debate the point, time exists.

I suspect that you have confused yourself by loading this notion of time with some additional baggage, but I have no idea where you picked that up. Time is simply the variable with which our universe changes in our perception. Since change occurs, such as a clock ticking away, this change is a measure of time.

Podge and Morbert seem to be trying to give you the benefit of all possible doubts, trying to infer some sensible stance from your statements, but I fear they are doomed to failure, if you truely believe this time I describe does not exist. If that is the case then there is really no reasoning with you since I cannot prove to you that I experience a changing universe (which, clearly, I do).

If however you accept that this notion of time does exist, then your problem is not with the existence of time, but rather of some property ascribed to it by a physical theory. However both General Relativity and QFT have been verified to high accuracy, and so there exists substantial evidence for the role of time in these theories.

roosh

Morbert wrote: »

Time is very much inferred. Yes, Quantum Field Theory and Relativity assume time exists as a facet of spacetime. Without this assumpion (i.e. If time did not exist as a part of spacetime), then these theories would not be formulated. The inferrence that these assumptions are true stems from the fact that these theories are not only consistent with a set of observations, but have predicted and been affirmed by new observations.

Have all of these observations been reliant on a clock to measure time? If not, then how has "time" been directly measured?

Morbert wrote: »

Do you have the same objections to the idea of spatial position?

That would be a separate thread, and something that I would probably have to look into more.

Morbert wrote: »

This is why I presented the stuff on metrics. The theories do not rely on time in a superficial way. Remember that, according to QFT and Relativity, time not only exists, but exhibits geometrical properties and interrelationships with space. If you reduce time to a tape measurer, you lose these connections, and the entire theory falls apart.


The thing is, if we do not assume spacetime exists, then we must assume a bunch of unobserved and unexplained hidden physical processes exist. These unobserved processes would draw the same criticism have against time, only much more so.

That is entirely irrelevant to the question on the existence of time. The same argument could have been made for the ptolmaic system, or indeed any incorrect theory that had the sun orbiting around the earth.


Just a simple question. If time exists then how is it measured?

roosh

onq wrote: »

How could any expansion occur without a time element?

ONQ.

how does expansion infer time?

roosh

Professor_Fink wrote: »

This is getting silly, particularly since you have now asserted in a previous post that time does not exist. I can no more prove that time exists than that I exist, but given the working assumption that I do in fact exist, as I perceive myself to ("cogito, ergo sum" and all that), then time exists.

that is a non-sequitur.

One can at least meet you and see that you manifest yourself in reality in a similar manner to themselves.

Professor_Fink wrote: »

We all experience a changing universe (in fact "cogito" implies a time ordered process), and we label the variable with which we parameterise this change "time". To say time does not exist is to say that we do not have this experience, which is essentially saying that we do not exist. But, since we're here to debate the point, time exists.

holy non-sequiturs batman!

indeed we live in what we perceive as a changing universe, and it is due to this perception that we believe that time exists. However, change does not mean that time exists, it is change that has lead us to create time in order to measure change.

To say that time does not exist is not to say that we do not have this experiecne, rather that we have misinterpreted that experience, in a similar, to how people perceived the sun to orbit the earth and the earth to be flat. The issue of time is however, a bit trickier, hence the difficulty in pinning it down.

Professor_Fink wrote: »

I suspect that you have confused yourself by loading this notion of time with some additional baggage, but I have no idea where you picked that up. Time is simply the variable with which our universe changes in our perception. Since change occurs, such as a clock ticking away, this change is a measure of time.

Indeed I could be loading it with some extra baggage, I could be completely mistaken in assuming that time is considered to be anything other than a human concept.

The issue is that saying that change is a measure of time, is a non-sequitur. It is the measurement of change which gives rise to the concept of time. It is ultimately the comparison of non-reality to [what quickly becomes non-] reality.

Professor_Fink wrote: »

Podge and Morbert seem to be trying to give you the benefit of all possible doubts, trying to infer some sensible stance from your statements, but I fear they are doomed to failure, if you truely believe this time I describe does not exist. If that is the case then there is really no reasoning with you since I cannot prove to you that I experience a changing universe (which, clearly, I do).

I fully believe that you experience a changing universe, but the point is that it is this perception of change that gives rise to the manmade concpet of time. It is based on our subjective perception of the earths orbit around the sun, which gives rise to the concepts of day and night, which give rise to the concepts of hours and minutes, and clocks.

Professor_Fink wrote: »

If however you accept that this notion of time does exist, then your problem is not with the existence of time, but rather of some property ascribed to it by a physical theory. However both General Relativity and QFT have been verified to high accuracy, and so there exists substantial evidence for the role of time in these theories.

Indeed, the role of time in these theories is something quite different to attributing inherent existence to the concept of time.


If time exists then how is it measured?

Professor_Fink

mangaroosh wrote: »

that is a non-sequitur.

One can at least meet you and see that you manifest yourself in reality in a similar manner to themselves.

Nonsense. I suspect you fancy yourself rather the philosopher, but you keep using language that has time implicit in it. Meeting someone implies a change from a state where you are not in contact with them to a state where you are. Meeting me would indeed imply the existence of time.

mangaroosh wrote: »

However, change does not mean that time exists, it is change that has lead us to create time in order to measure change.

No, change occurs with respect to some variable. That variable we call time.

mangaroosh wrote: »

The issue is that saying that change is a measure of time, is a non-sequitur. It is the measurement of change which gives rise to the concept of time. It is ultimately the comparison of non-reality to [what quickly becomes non-] reality.

You're going off the rails here. Change is a measure of time, indeed that is how time is generally defined. You clearly have some entirely different definition of time in mind, but I have no idea what that may be.

mangaroosh wrote: »

I fully believe that you experience a changing universe, but the point is that it is this perception of change that gives rise to the manmade concpet of time. It is based on our subjective perception of the earths orbit around the sun, which gives rise to the concepts of day and night, which give rise to the concepts of hours and minutes, and clocks.

That is complete nonsense. Time is in no way dependent on the existence of the earth or the sun. Sure, seconds are a rather arbitrary unit for time, but that has nothing to do with the existence of the dimension. I think perhaps you are assuming that by the existence of time we are saying that only the present exists, or that the present has some special significance. We certainly don't mean that. What we mean is that there is a parameter (which we call time) relative to which change is measured.

mangaroosh wrote: »

If time exists then how is it measured?

With a clock. Note I don't define a clock to be something that measures time, I define time to be what is measured by a clock. A clock can be essentially anything which we perceive to change in a predictable manner.

Morbert

mangaroosh wrote: »

Have all of these observations been reliant on a clock to measure time? If not, then how has "time" been directly measured?

That is entirely irrelevant to the question on the existence of time. The same argument could have been made for the ptolmaic system, or indeed any incorrect theory that had the sun orbiting around the earth.

No. The structure of spacetime is used to infer expected particle interactions. Take a simple example: A real scalar field lagrangian.



Such equations can be used to derive equations of motion, and are essential in particle physics. Notice the term



in the equation. This term is the spacetime metric, and it is very important. Without it, we can't do quantum mechanics. We can't predict how particles will behave. Now what you are saying is "actually, even though quantum field theory, and the assumption that time exists as a facet of spacetim, is very successful in telling us what we will observe, time doesn't actually exist, and QFT is only an effective theory, like the geocentric model." I am asking you in what way is QFT effective. If what we call time is some man made illusion, then how is QFT effectively constructed? You seem to simply be assuming QFT is emergent from a timeless universe, without putting forth any argument as to how it is emergent. That is a massive assumption, a much larger one than the assumption that clocks measure time.

That would be a separate thread, and something that I would probably have to look into more.

Just a simple question. If time exists then how is it measured?

I think I see the problem here. Clocks measure time by recording change with respect to it. Now you seem to be claiming "that is just the measurement of change, and not with respect to time". But I put it to you that change without respect to anything makes no sense, as "with respect to" is implied. Take some examples: The speed limit changes with respect to where you are in the country. Radio stations change with respect to frequency. Laws change with respect to what country you are in, and velocity is change in position with respect to time. So if you say time does not exist, then what is the change that a clock measures? What is it with respect to?


[edit]- I am reminded of an xkcd comic that was recently posted in another forum

roosh

Professor_Fink wrote: »

Nonsense. I suspect you fancy yourself rather the philosopher, but you keep using language that has time implicit in it. Meeting someone implies a change from a state where you are not in contact with them to a state where you are. Meeting me would indeed imply the existence of time.

Indeed our language has time implicit in it, that does not mean however that time exists, as it is equally likely that the temporal nature of our language is as much attributable to our misperception of the universe.

The issue is, that a change of state does not necessarily imply the existence of time. Or if it does, then how does it?

Professor_Fink wrote: »

No, change occurs with respect to some variable. That variable we call time.

It is an assertion that change occurs with respect to some variable. What evidence is there to suggest that change occurs with respect to some variable?

Professor_Fink wrote: »

You're going off the rails here. Change is a measure of time, indeed that is how time is generally defined. You clearly have some entirely different definition of time in mind, but I have no idea what that may be.

How is change a measure of time?

Professor_Fink wrote: »

That is complete nonsense. Time is in no way dependent on the existence of the earth or the sun. Sure, seconds are a rather arbitrary unit for time, but that has nothing to do with the existence of the dimension. I think perhaps you are assuming that by the existence of time we are saying that only the present exists, or that the present has some special significance. We certainly don't mean that.

The emboldened would be part of the contention that time does not exist.

Professor_Fink wrote: »

What we mean is that there is a parameter (which we call time) relative to which change is measured.

Change is not measured against an [inherently existent] parameter. How change is measured is against a phenomenon that is taken to be a standard unit of measurement.

For example, the atomic clock uses the microwave radiation of electrons as they change energy as the standard unit, against which other things are measured, while a muon clock uses the lifetimes of muons as the standard against which things are measured.

When an atomic clock is used to measure the length of "time" it takes for change to occur, what is actually being compared, is the change of state relative to the number of times the measuring device registers the microwave emissions.

In simple, hopefully not too basic, terms, if the distance light travels per second were to be stated, it would be the distance relative to the number of microwave emissions.

The assumption that the number of microwave emissions is a measure of something else is a non-sequitur.

Professor_Fink wrote: »

With a clock. Note I don't define a clock to be something that measures time, I define time to be what is measured by a clock. A clock can be essentially anything which we perceive to change in a predictable manner.

the contention is that "Time" is a manmade system of measurement, alá the metric system, where a naturally occuring phenomenon is [arbitrarily] taken as a standard unit, against which other things e.g. changes of state, are compared.

Podge_irl

mangaroosh wrote: »

the contention is that "Time" is a manmade system of measurement, alá the metric system, where a naturally occuring phenomenon is [arbitrarily] taken as a standard unit, against which other things e.g. changes of state, are compared.

That doesn't make sense. "Seconds" are a man-made measuring system just like the metric system, but time is perfectly equivalent to distance. You may as well be arguing that distance doesn't exist either.

What evidence is there to suggest that change occurs with respect to some variable?

How else do you quantity what you mean by change? Its the very definition of the word.


I'm sorry, but you're just not making an awful lot of sense.

roosh

Morbert wrote: »

No. The structure of spacetime is used to infer expected particle interactions. Take a simple example: A real scalar field lagrangian.



Such equations can be used to derive equations of motion, and are essential in particle physics. Notice the term



in the equation. This term is the spacetime metric, and it is very important. Without it, we can't do quantum mechanics. We can't predict how particles will behave. Now what you are saying is "actually, even though quantum field theory, and the assumption that time exists as a facet of spacetim, is very successful in telling us what we will observe, time doesn't actually exist, and QFT is only an effective theory, like the geocentric model." I am asking you in what way is QFT effective. If what we call time is some man made illusion, then how is QFT effectively constructed? You seem to simply be assuming QFT is emergent from a timeless universe, without putting forth any argument as to how it is emergent. That is a massive assumption, a much larger one than the assumption that clocks measure time.

The issue is that the "time" that is used is based on a self contained system, that has an incorrect assumption inherent in it. Mathematical equations are based on certain assumptions, and these assumptions will be inherent in any equations that are based on the assumptions.

If a clock is assumed to measure time, then its use in any experiment will appear to support the assumption that time exists. This however, is a self-contained system.

This is may be how QFT is effectively constructed. The assumption that a clock measures time is a fundamental assumption, and the proposition that QFT emerges from a timeless universe is, to an extent, based on it.

Morbert wrote: »

I think I see the problem here. Clocks measure time by recording change with respect to it. Now you seem to be claiming "that is just the measurement of change, and not with respect to time". But I put it to you that change without respect to anything makes no sense, as "with respect to" is implied. Take some examples: The speed limit changes with respect to where you are in the country. Radio stations change with respect to frequency. Laws change with respect to what country you are in, and velocity is change in position with respect to time. So if you say time does not exist, then what is the change that a clock measures? What is it with respect to?

A clock does not necessarily measure change, what a clock does is provide a standard unit, against which change is measured, just as a metre provides a standard unit against which distance is measured.

If we use the example of the atomic clock again (apologies for the overuse), then we can see that the microwave emissions of electrons is taken as the standard unit, against which change is measured.

If we take the simple equation of speed being equal to distance over time, and assume the distance traveled is, say, 1 metre.

The speed would then be worked out as the 1 metre [the object moved, with respect to its original position.], divided by the number of microwave emissions that occured.

This would give a speed of 1 metre per x number of microwave emissions.

Morbert wrote: »

[edit]- I am reminded of an xkcd comic that was recently posted in another forum

I must admit I chuckled at that one!