More about Time Definition

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  • #26
maumer
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Reading previous posts:


Antiproton 07-08-2003:

"Instead, consider more regular phenomina like the period of atomic radiation."

Russ_watters 10-07-2003:
"Transit of the sun (sundial), vibration of quarz chrystals (typical watch), vibration of cesium atoms (atomic clock)."

Antiproton 10-10-2003:
"However, if in this universe you have a ball NOT at 0k, then one can assume the molecules of the ball move in some fashion. One can therefore distinguish between 1 state and another state."
In these posts you (Anti&Russ) use the motion of something to define time: atomic radiation period, cesius atom vibration, etc. In this way, you make a close correspondence between one vibration and one unit of time. But Antiproton said: "First, time is not measured relative to motion... motion is measured relative to time. v=dx/dt."
I will believe you when you will give me a time definition without starting from motion. You are using motion to define time that measures motion. A snake eating it's tail.
Reading last Antiproton post 10-10-2003:
You've made an example using two systems: A and B. Each one has two events inside: a(A), b(A), a(B), b(B). I suppose A and B are isolated one from the other, otherwise A and B are the same system and your example is untrue. Now i'm asking myself in wich system do you take your "reference frame"? Inside system A? Staying in A you cannot see B system and viceversa. Staying in A you don't know a(B) and b(B) and their order in reference of a(A) and b(A) because the two systems are isolated. Are you creating a C system in wich put A and B and looking them from C? In this case you choose an external "reference frame" and C links A and B, because if you are looking them, you interact whith them and they aren't still isolated.
Returnig in my "artificial example": in my system there is a ball. It exists, and it makes gravity field and it is surrounded by space. You haven't still answered: could you experiment gravity, space, time in my system?
 
  • #27
russ_watters
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Originally posted by maumer
In these posts you (Anti&Russ) use the motion of something to define time...
No, we use the motion of something to MEASURE time. Huge, huge, huge, huge difference. The fact that certain events do occur at regular intervals in time is a fundamental piece of evidence for time's existence. And not all of those examples depended on motion. Periodic atomic radiation (for example) isn't necessarily motion.
I will believe you when you will give me a time definition without starting from motion. You are using motion to define time that measures motion.
It doesn't have to be motion, it just has to be an observable, repeating event. In fact, even in the examples I gave, motion isn't what is measured, its electrical signals produced by motion or apparent motion in the case of the shadow on the sundial.
Now i'm asking myself in wich system do you take your "reference frame"?
Your reference frame can be wherever you wish.
...could you experiment gravity, space, time in my system?
Not a complete sentence but if you mean could you experiment on those things, the answer is yes, though you'll have to clarify what you mean by "space". You also may need to clarify what type of experiments you want to perform. Planets for example are balls surrounded by space (for the purpose of some experiments) and a great deal can be learned about their properties just by observing them and how they interact with other nearby objects. But what does this have to do with time?

Your arguement here has been very much like arguing against the concept of "shoes." You gave clear examples of how to measure and observe it, described the definition, and then said it doesn't exist. Huh? Sorry, but if something exists that fits the definition, then its axiomatic. Shoes exist. Maybe you are arguing that "shoes" aren't "sandals" but if so, you're mis-applying the definition of "sandals" to disprove "shoes." You can't do that.
 
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  • #28


Originally posted by maumer
Reading previous posts:


In these posts you (Anti&Russ) use the motion of something to define time: atomic radiation period, cesius atom vibration, etc. In this way, you make a close correspondence between one vibration and one unit of time. But Antiproton said: "First, time is not measured relative to motion... motion is measured relative to time. v=dx/dt."
I will believe you when you will give me a time definition without starting from motion. You are using motion to define time that measures motion. A snake eating it's tail.
Reading last Antiproton post 10-10-2003:
You've made an example using two systems: A and B. Each one has two events inside: a(A), b(A), a(B), b(B). I suppose A and B are isolated one from the other, otherwise A and B are the same system and your example is untrue. Now i'm asking myself in wich system do you take your "reference frame"? Inside system A? Staying in A you cannot see B system and viceversa. Staying in A you don't know a(B) and b(B) and their order in reference of a(A) and b(A) because the two systems are isolated. Are you creating a C system in wich put A and B and looking them from C? In this case you choose an external "reference frame" and C links A and B, because if you are looking them, you interact whith them and they aren't still isolated.
Returnig in my "artificial example": in my system there is a ball. It exists, and it makes gravity field and it is surrounded by space. You haven't still answered: could you experiment gravity, space, time in my system?
Hello there.
What do exactly we consider? Whether time does exist or it doesn’t? What is time? Whether is time a dimension of space, enclosing us, or is it part of metrics?
Generally, time is not illusion, but motion is. Maybe, the problem is to define time. However, this problem can also be solved. If we define time by using the quantum field theory, we solve this problem. Within the framework of quantum field theory time does exist as ordering of various states of the different physical systems. Be sure - time does exist, but motion doesn’t. However, we can use the motion to measure (not to define) time.
 
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  • #29
jcsd
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Motion does exist, if you don't think it does your using a far too stringent defintion of exists that rules out even easily observed phenomena.
 
  • #30
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Any argument proving time does not exist may likewise be used to disprove the existence of space. For instance, try proving that we live in a 2-D space, rather than 3-dimensional.
 
  • #31
Originally posted by jcsd
Motion does exist, if you don't think it does your using a far too stringent defintion of exists that rules out even easily observed phenomena.
Within the framework of quantum field theory secondary quantization implies that motion doesn't exist, i.e. time is defined as transition of a physical system with one set of observable values (say, A1-state) to another set of observable values (say, A2-state). If A1-state differs from A2-state by generalized coordinates, then it seems to us that we observe motion, nothing else.
 
  • #32
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I would go so far as to say time is axiomatic. You couldn't prove the non-existence of time any more than you could disprove the communtivity of the integers under addition. It's there, and we have to deal with it. Instead, we should be discuss the nature of time, i.e. is it discrete or continuous and so on.
 
  • #33
jcsd
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Originally posted by Antiproton
I would go so far as to say time is axiomatic. You couldn't prove the non-existence of time any more than you could disprove the communtivity of the integers under addition. It's there, and we have to deal with it. Instead, we should be discuss the nature of time, i.e. is it discrete or continuous and so on.
Yes indeed; I was going to post, pretty much the same thing: the existance of time is just as axiomatic as the existance of the x, y and z directions.
 
  • #34
jcsd
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Originally posted by Anton A. Ermolenko
Within the framework of quantum field theory secondary quantization implies that motion doesn't exist, i.e. time is defined as transition of a physical system with one set of observable values (say, A1-state) to another set of observable values (say, A2-state). If A1-state differs from A2-state by generalized coordinates, then it seems to us that we observe motion, nothing else.
But surely if you have time and a spatial axis then you have dx/dt.
 
  • #35
Originally posted by Antiproton
I would go so far as to say time is axiomatic. You couldn't prove the non-existence of time any more than you could disprove the communtivity of the integers under addition.
Originally posted by jcsd
Yes indeed; I was going to post, pretty much the same thing: the existance of time is just as axiomatic as the existance of the x, y and z directions.
Not exactly that way. The system of axioms (of a specific physical theory) may content time as axiom, and may not... time can be only a theorem (e.g. there are axioms of three-dimensional linear space and four-dimensional invariant, such as four-dimensional interval in the Minkowski space-time).
Originally posted by Antiproton
It's there, and we have to deal with it. Instead, we should be discuss the nature of time, i.e. is it discrete or continuous and so on.
If we agree with time definition within the framework of quantum field theory, then time is exactly discrete.

Originally posted by jcsd
But surely if you have time and a spatial axis then you have dx/dt.
Not exactly that way. Even if A1-state differs from A2-state by generalized coordinates and linear component of four-momentum is not equal to zero (of course it isn't) you can't observe motion, because you can't observe trajectory. You can localize it with a relative exactitude, nothing else.
 
  • #36
russ_watters
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Originally posted by jcsd
Yes indeed; I was going to post, pretty much the same thing: the existance of time is just as axiomatic as the existance of the x, y and z directions.
Ditto.
 
  • #37
jcsd
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Originally posted by Anton A. Ermolenko
Not exactly that way. The system of axioms (of a specific physical theory) may content time as axiom, and may not... time can be only a theorem (e.g. there are axioms of three-dimensional linear space and four-dimensional invariant, such as four-dimensional interval in the Minkowski space-time).

If we agree with time definition within the framework of quantum field theory, then time is exactly discrete.


Not exactly that way. Even if A1-state differs from A2-state by generalized coordinates and linear component of four-momentum is not equal to zero (of course it isn't) you can't observe motion, because you can't observe trajectory. You can localize it with a relative exactitude, nothing else.
Most physical theories DO have the existance of time as an axiom, infact I'm struggling to think of theory in which time is an emergant property (though I'm not saying there isn't one, I remeber years ago reading a book by Paul Davies in which he suggests time may of been an emergant property from the properties of the initla conditons in the universe).

Also, I will not claim to be an expert on QFT but I've yet to hear of a widely accepted physical theory which quantizes time.
 
  • #38
maumer


Russ
No, we use the motion of something to MEASURE time.
Antiproton
First, time is not measured relative to motion... motion is measured relative to time. v=dx/dt.
Decide what you are doing!!
 
  • #39
maumer
Originally posted by Anton A. Ermolenko


Not exactly that way. Even if A1-state differs from A2-state by generalized coordinates and linear component of four-momentum is not equal to zero (of course it isn't) you can't observe motion, because you can't observe trajectory. You can localize it with a relative exactitude, nothing else.
Hello Ermolenko,
are you talking about the evanescent behaviour of particles? If yes, i agree with you that we can't see motion. But you see time in the transaction betweem two states. The transaction, at the end, is a result of a sort of a motion. Something has moved and you define time with a transaction; a sort of motion.
I can conlude that fluffy bunny is in right when he says that time is axiomatic. But an axiom is what you keep true although it could not be. What i was trying to explain is that time is an artificial creation to link some movement, that we use to set regular intervals like cesius atom vibration, to an other motion. I'm trying to say that you call time a motion. But time really doesn't exist. We can count how many vibrations cesius does and say: "three vibrations ago i was.....". O.K.!! I can accept it. But we are referring our lives to a motion of an atom. Not to time. You are calling time the atom vibration.
O.K. fluffy bunny, you're in right.
 
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  • #40
Originally posted by jcsd
Most physical theories DO have the existance of time as an axiom, infact I'm struggling to think of theory in which time is an emergant property (though I'm not saying there isn't one, I remeber years ago reading a book by Paul Davies in which he suggests time may of been an emergant property from the properties of the initla conditons in the universe).

Also, I will not claim to be an expert on QFT but I've yet to hear of a widely accepted physical theory which quantizes time.
Actually you take one quantization of continuous time for descrete nature of time. Within the framework of QFT the time is discrete. The secondary quantization concept allow to sustitude the time with indexes, because the main difference A1-state from A2-state is the index. We need the time only for synchronization of different physical systems. But it really is discrete.
Originally posted by maumer
Hello Ermolenko,
are you talking about the evanescent behaviour of particles? If yes, i agree with you that we can't see motion. But you see time in the transaction betweem two states. The transaction, at the end, is a result of a sort of a motion. Something has moved and you define time with a transaction; a sort of motion.
Of course not. Transaction from A1-state to A2-state not always implies a modification of localization in three-dimensional space, e.g. A1-state may differs from A2-state by number of virtual photons. And where is motion?
 
  • #41
russ_watters
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Originally posted by maumer
Decide what you are doing!!
You took my quote out of context. You can do both depending on the type of events/motion being observed.
 
  • #42
maumer
Originally posted by Anton A. Ermolenko
We need the time only for synchronization of different physical systems.

So time is the difference between two states?
 
  • #43
Originally posted by maumer
So time is the difference between two states?
Bingo! If we agree with the concept of secondary quantization within the framework of QFT, then of course yes - the (local) time is only difference between two nearest states of the same physical system.
 
  • #44
maumer
Originally posted by Anton A. Ermolenko
Bingo! If we agree with the concept of secondary quantization within the framework of QFT, then of course yes - the (local) time is only difference between two nearest states of the same physical system.
Mr. Bingo, could you assert time is axiomatic, too? A human mean?
 
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