What is "time"

[MattMars]

Three questions, Matt:

What's a record?
What's a turntable?
How old are you?

Is it a wonder that a geezer like you denies the existence of time? (Oops. That's four questions)

Hi Landau,
v funny , though consider, even if there is time, the the stuff that makes me up, and you up , and even your pc etc, must basically be the same age. just becasue some material is or is no part of a persons body doesn't mean its not doing something. So the matter that makes up a body we might say is 20, must be the same age as the matter making up a baby, or a toy. just becasue some collection of matter looks and interacts differently, or is active or inert, doesn't mean it is older or younger than anything else, or that a thing called time is passing. (imo)

But the point re the record is of course to simplify things. my point being if we want to understand something it is usually best to first understand it with the simplest examples, ( that's why einsteinien thought experiments are so simple and so useful).

So the position of a needle at a specific location on a circular disc, can be seen for what it is, a specific place, and not 2 'minutes' into something.
do you see what i mean?
mm

 

[PhysBang]

Well said that man.

NB: as far as SR is concerned, a frame is little more than "a state of motion".

If you accelerate, you change your state of motion, and you have a different reference frame. That apart, a frame is a rather abstract thing. It's not as if you can point up to the clear night sky and say "look, there's a reference frame".

This is stupidly untrue.

According to SR, a reference frame is a system of coordinates in which one Newtonian mechanics provides a good approximation to physical systems.

http://www.fourmilab.ch/etexts/einstein/specrel/www/

This is not something that should be in dispute.

Many people often use a shorthand to speak of a reference frame that belongs to some observer and object. This is useful shorthand, often, but it can lead to mistakes. All objects are always in all reference frames that we could imagine. We can always use whatever reference frame we wish to do physics. The standard example is driving a car and determining our speed: we always use a reference frame in which the road is at rest rather than the reference frame in which we are at rest.

We can, with care, speak of reference frames as being "in motion" to one another. We can't, however, say that reference frames are merely states of motion.

 

[Farsight]

This is a fascinating discussion that ignores something very important that Einstein wrote about clocks, and in plain language.

It doesn't ignore what Einstein said. Read your own quote. He talked about clocks and the law of motion and the definition of time. And look at what you wrote, but insert the word "light": a claim about light clocks is a claim about the way that a physical system behaves in a location and about the way that system behaves when in a different location. There's no time flowing inside a light clock. When the light clock goes slower it's because light goes slower. Hence Einstein saying a curvature of rays of light can only occur whene the speed of light varies with position. Understand time, and you understand gravity.

 

[Billy T]

This is a fascinating discussion that ignores something very important that Einstein wrote about clocks, and in plain language.

In Relativity, Einstein writes, 'Clocks, for which the law of motion is any kind, however irregular, serve for the definition of time. We have to imagine each of these clocks fixed at a point on the non-rigid reference-body. These clocks satisfy only the one condition, that the “readings” which are observed simultaneously on adjacent clocks (in space) differ from each other by an indefinitely small amount.' The important thing about clocks is not their reading, but the idea that we have, in principle, some physical system that have "readings" (identifiable properties and changes of state between those properties) and that behaves in the same way in the same location. A claim about clocks is a claim about the way that a physical system, effectively any possible physical system, behaves in a location and about the way that system behaves when in a different location/circumstance or when moved away from a location/circumstance (using location in any sort of spatial geometry). It is about the behavior, in principle, of every possible kind of physical system (hence the Equivalence Principle in its various forms); it is about the timing of these systems. It is a commitment that in understanding the cause and effect within physical systems and between them, we need to include some account of timing.

I agree with all that & can illustrate with simple example: Candle A (fatter that candles B) stops burning when the second of two candles B goes out if they are in the same content of air no matter where in the same G they are.

 

[PhysBang]

2) I.e. state it again (without reference to human skills.) Also I did not see any that was not an unproven assertion such as "Time is that which does X." as I think the assertion that time does anything causal is false. For example it is O2 that makes /causes iron to rust. - Take away the O2 and the rusting stops.

Without time, one cannot adequately explain things like time dilation and the failure of simultaneity. So it seems to be a necessary thing to adequately describe the causal structure of the universe.

At the quantum level time if it flows at all, flows either way.

This is a matter of interpretation. If there are collapse events, then these provide a clear direction in time.

 

[Farsight]

This is stupidly untrue. According to SR, a reference frame is a system of coordinates in which one Newtonian mechanics provides a good approximation to physical systems.

It isn't stupidly untrue. Space is not divided into little squares, there are no markers dotted throughout it, that system of coordinates is an abstract thing. And you typically use a different abstract system of coordinates when you're moving fast relative to me. You use a different reference frame, only it isn't something that's actually there.

This is a matter of interpretation. If there are collapse events, then these provide a clear direction in time.

Then point in that direction. When you can't, you may finally appreciate that some things you take for granted just aren't there. They are abstractions, and they are not to be confused with reality.

 

[PhysBang]

It doesn't ignore what Einstein said.

Yes, and now you;re doing it again.

Why do you ignore Einstein?

Read your own quote. He talked about clocks and the law of motion and the definition of time.

Why do deny what he actually wrote. He writes, 'Clocks, for which the law of motion is any kind, however irregular, serve for the definition of time.' [My emphasis.] You think of clocks as only regular, pseudo-SR things. Einstein was able to move past this.

And look at what you wrote, but insert the word "light": a claim about light clocks is a claim about the way that a physical system behaves in a location and about the way that system behaves when in a different location. There's no time flowing inside a light clock. When the light clock goes slower it's because light goes slower. Hence Einstein saying a curvature of rays of light can only occur whene the speed of light varies with position. Understand time, and you understand gravity.

You want to write into Einstein your own idea that everything is made of light. Sadly for you, but great for us, Einstein did not write this. He wrote about any physical system, regardless of its composition.

You are welcome to demonstrate that your crazy idea can possible produce a usable physics. So far, we all know that you can't do physics and so your ideas are only your own fantasy.

 

[PhysBang]

It isn't stupidly untrue. Space is not divided into little squares, there are no markers dotted throughout it, that system of coordinates is an abstract thing.

Farsight, you are performing a fallacy known as a "Straw man" argument.

It is sad that you have never learned physics. Nonetheless, a system of coordinates is no less abstract when it is called "a system of coordinates" than when it is called "a reference frame" or "a frame of reference". At no time did I claim that it wasn't abstract. Please read the link I provided.

And you typically use a different abstract system of coordinates when you're moving fast relative to me.

Again, this is a bonkers thing that someone who has never done a physics problem might believe. I use whatever system of coordinates is convenient given the measuring apparatus available to me.

Then point in that direction. When you can't, you may finally appreciate that some things you take for granted just aren't there. They are abstractions, and they are not to be confused with reality.

You see, overly concerned with restricting the use of valuable metaphor. If I were you, I would spend my time learning physics.

 

[Farsight]

Yes, and now you;re doing it again. Why do you ignore Einstein? Why do deny what he actually wrote. He writes, 'Clocks, for which the law of motion is any kind, however irregular, serve for the definition of time.' [My emphasis.] You think of clocks as only regular, pseudo-SR things. Einstein was able to move past this.

I don't ignore Einstein. I'm always referring to him to back up what I say. You should read this:



http://www.amazon.co.uk/World-without-Time-Forgotten-Einstein/dp/0465092942

You want to write into Einstein your own idea that everything is made of light. Sadly for you, but great for us, Einstein did not write this. He wrote about any physical system, regardless of its composition. You are welcome to demonstrate that your crazy idea can possible produce a usable physics. So far, we all know that you can't do physics and so your ideas are only your own fantasy.

It isn't my idea, pair production is not some fantasy, and abuse is no substitute for evidence and references. Especially when you're losing the argument.

Now, can you point in that time direction?

Don't think you can evade answering this question with abuse. It will be noticed.

 

[PhysBang]

I agree with all that & can illustrate with simple example: Candle A (fatter that candles B) stops burning when the second of two candles B goes out. is their in the same content of air no matter where in the same G they are.

Yet this doesn't address how we assign systems of coordinates when one candle is in motion relative to the other. Nor what happens when we move one candle away from another, through a gravitational potential, and then back again.

 

[PhysBang]

I don't ignore Einstein. I'm always referring to him to back up what I say.

YEs, you cherry-pick him and you just demonstrated that you ignore him by ignoring that direct quotation.

You should read this:

View attachment 58

http://www.amazon.co.uk/World-without-Time-Forgotten-Einstein/dp/0465092942

What makes you think that I haven't read it? You wave it around like a talisman, but it doesn't seem to have nay support for any of your claims. Have you read it?

It isn't my idea, pair production is not some fantasy,

Your interpretation of it it your fantasy. You know that physicists do not share your interpretation and you know that you can't do any physics with your interpretation.

and abuse is no substitute for evidence and references.

So when will you give us evidence? When will you show us an example done with your physics?

 

[krash661]

this topic is now officially destroyed.
it has become like the rest,
nothing more than,
" no it is not, yes it is " nonsense.

 

[Billy T]

Without time, one cannot adequately explain things like time dilation and the failure of simultaneity. So it seems to be a necessary thing to adequately describe the causal structure of the universe. ...

These strange to humans things are not realy "explained." They are described by equations, that as post 28 shows, do not need to mention time. What one ALWAYS DOES, IS COMPARE ONE (or more) processes to another. In my fat vs thinner candle example that is obvious. Clocks are a convenient way to compare every things to their tick process I. e. I could have said (as we usually do) the fat candle burns for 2x and the thin one for x ticks of the clock making no direct comparison between the candles which can always be done for ALL comparisons with no reference to time, as proved in post 28.

 

[PhysBang]

These strange to humans things are not realy "explained." They are described by equations, that as post 28 shows, do not need to mention time.

Your post shows nothing. It, charitably, applies to a certain limited set of circumstances. No math is addressed in enough detail to establish the grand claims that you have been making. It certainly doesn't address the claims about how processes are different due to relativistic effects.

 

[OnlyMe]

Most of this discussion has degraded to the point of talking past one another. No one it seems has taken the time to work out any common definition of time itself, which makes answering the question in the OP or reaching any consensus in the pursuing discussion, near impossible. Many here are talking past one another or simply arguing against the argument(s) of others.., without providing any clear definition of time, as a basis for any discussion. Or so it seems from someone attempting to follow the discussion as it jumps 10 to 20 posts in a session.

Time is an abstract construct we use to describe our experience and measurement of change, usually within the context of a previously agreed upon standard.., designated as a clock... Itself no more than a mechanism measuring some regular, systematic and uniform rate of change.

• Is time real? Yes, but in what context is it real?
• Does time flow? Again the answer is yes! But in what sense or manner does it flow?

Both of these questions can be answered by analogy, or comparison with the following.

• Are ideas real?
• Is consciousness real..? Does it flow?
• Is awareness real and does it flow?
• Are numbers and the mathematics based on numbers and abstract symbols real?

To all of the above the answer is yes, and yet none of the above have any direct physical existence in reality. Though they are all descriptive of reality in some way.

Time is an abstract concept we use to describe our experience of change in the world around us, and to our credit, even change in how we imagine the world beyond our direct observation, to take place. Time t in mathematics, is as real as the numbers 1, 2, 3,... and the symbols we use to communicate sometimes complex ideas. However, within the context of experience, only as it describes change or the potential for change, is it real in itself.., and still even then without that change there is no time to discuss.

Is there a past, present and future? Certainly! Is it time from which the past and future emerge? No, it is change.., and change is sometime we measure and communicate through the abstract concept we call time.

We use time to describe both changes in physical systems and things, which though they may emerge from physical processes, have no independent physical substance.

• Ideas
• Dreams
• Consciousness and awareness
• And the logical extension of what we know from direct experience, to how we imagine what we cannot touch and/or measure directly...

Time is both real and an abstract concept used to describe change. It is a necessisary concept and component in understanding the world around us.., and in the mathematics we use to communicate, describe and explore aspects, of the world which would otherwise be beyond description and understanding.

One side comment, that is almost never considered, is that the world we see and experience is already the past. Even setting aside the fact that different forms of sensory information about our environment reaches us at different speeds.., it takes between 300 and 400 microseconds (or is it milliseconds?), to assemble that information into what we experience as NOW. We all live in the past, even as we believe it to be the present.

 

[MattMars]

Without time, one cannot adequately explain things like time dilation and the failure of simultaneity. So it seems to be a necessary thing to adequately describe the causal structure of the universe.


This is a matter of interpretation. If there are collapse events, then these provide a clear direction in time.

Hi PB,

First, to all, can we tone it down a bit again pls. I thought we all had a basic agreement to be polite. Just my opinion.

PB, with respect, Re "Without time, one cannot adequately explain things like time dilation and the failure of simultaneity. So it seems to be a necessary thing to adequately describe the causal structure of the universe",

I may be wrong, but I think I can adequately explain those things.
mm

 

[paddoboy]

(1) Ok give your alternative, If better than "anything I can infer for data is real." I object to definitions that depend on human's mental abilities and conventions. Definitions should apply before there were humans.

I have given my definition, as simplistic as it is.....
"TIME: That which stops everything from happening together."
Now as much as you will dismiss that with claims of just mental conventions and conciousness it holds true in many other respects also, that have been mentioned again and again in this thread.
And along with the many other furphies such as clocks, Unicorns and whatever, just because there were no humans about in the first 99% of the history of the Universe, does not for one minute invalidate the reality of time, in my opinion.
A few other points......Your request for a reference to Principia and the mention of time has been forthcoming in post 293...Since you have failed to acknowledge it, I will presume you have missed it.
And of course that one reference is not the be all and end all of this debate about the reality or otherwise of time.

Then we have the fact that our ignorance of the true nature of time, means that the opinions expressed here, both positive and negative are just that....In reality, we cannot really say.
Yet only one person of all the naysayers has acknowledged this fact...Matt M, the initiator of the thread, and the one person who has written a book about the subject.
He certainly has my respect in that regard, noting of course that I have not ventured away from my own positive opinion re time for the many reasons already stated and the many references confirming my stance.

Which brings us to your claim re your maths prove that time does not exist.
As a self admitted mathematical dunce, I'm not even going to attempt to try and disprove your proof. But I do have a couple of questions.....
How come if you have mathematical proof of time not being real, that you don't present it to a proper scientific review panel for evaluation and peer review?
How come that the likes of Carroll, Smolin, Kaku, Thorne and many many more have not recognised this mathematical proof?
Are you claiming that [1] they are incapable of fathoming your workings and methodology, [2] They are insidiously ignoring it and partaking in a conspiracy so often claimed by our Alternative hypothesis pushers here and elsewhere, or [3]No one yet in the halls of Acadamia and science has thought of this proof.
Or might it just be either that you have [1] made an error, or [2] The mathematics is not valid and just does not logically apply.

With the second law of thermodynamics and entropy, I again do not find anything of substance in your analogies to discredit it and the reference to the arrow of time.
On that same subject here is a series of questions put and answered by Sean Carroll.

http://preposterousuniverse.com/eternitytohere/faq.html

 

[paddoboy]

Most of this discussion has degraded to the point of talking past one another. No one it seems has taken the time to work out any common definition of time itself, which makes answering the question in the OP or reaching any consensus in the pursuing discussion, near impossible. Many here are talking past one another or simply arguing against the argument(s) of others.., without providing any clear definition of time, as a basis for any discussion. Or so it seems from someone attempting to follow the discussion as it jumps 10 to 20 posts in a session.

Time is an abstract construct we use to describe our experience and measurement of change, usually within the context of a previously agreed upon standard.., designated as a clock... Itself no more than a mechanism measuring some regular, systematic and uniform rate of change.

• Is time real? Yes, but in what context is it real?
• Does time flow? Again the answer is yes! But in what sense or manner does it flow?

Both of these questions can be answered by analogy, or comparison with the following.

• Are ideas real?
• Is consciousness real..? Does it flow?
• Is awareness real and does it flow?
• Are numbers and the mathematics based on numbers and abstract symbols real?

To all of the above the answer is yes, and yet none of the above have any direct physical existence in reality. Though they are all descriptive of reality in some way.

Time is an abstract concept we use to describe our experience of change in the world around us, and to our credit, even change in how we imagine the world beyond our direct observation, to take place. Time t in mathematics, is as real as the numbers 1, 2, 3,... and the symbols we use to communicate sometimes complex ideas. However, within the context of experience, only as it describes change or the potential for change, is it real in itself.., and still even then without that change there is no time to discuss.

Is there a past, present and future? Certainly! Is it time from which the past and future emerge? No, it is change.., and change is sometime we measure and communicate through the abstract concept we call time.

We use time to describe both changes in physical systems and things, which though they may emerge from physical processes, have no independent physical substance.

• Ideas
• Dreams
• Consciousness and awareness
• And the logical extension of what we know from direct experience, to how we imagine what we cannot touch and/or measure directly...

Time is both real and an abstract concept used to describe change. It is a necessisary concept and component in understanding the world around us.., and in the mathematics we use to communicate, describe and explore aspects, of the world which would otherwise be beyond description and understanding.

One side comment, that is almost never considered, is that the world we see and experience is already the past. Even setting aside the fact that different forms of sensory information about our environment reaches us at different speeds.., it takes between 300 and 400 microseconds (or is it milliseconds?), to assemble that information into what we experience as NOW. We all live in the past, even as we believe it to be the present.

Excellently put!

 

[MattMars]

These strange to humans things are not realy "explained." They are described by equations, that as post 28 shows, do not need to mention time. What one ALWAYS DOES, IS COMPARE ONE (or more) processes to another. In my fat vs thinner candle example that is obvious. Clocks are a convenient way to compare every things to their tick process I. e. I could have said (as we usually do) the fat candle burns for 2x and the thin one for x ticks of the clock making no direct comparison between the candles which can always be done for ALL comparisons with no reference to time, as proved in post 28.

Hi Billy,
You know I think your basically on the right track (though I always try to keep open minded about being wrong, because otherwise we are not being scientific), but can I politely request fewer CAPS,
mm

 

[MattMars]

Excellently put!

Hi Pad,
Yes there is some segregation, but maybe that's just par for the course and just a phase, you reference a lot of peoples works, but they must be one step away from the original source. So perhaps we can inject some fresh (and hopefully refreshing)direction to the conversation.

To which I suggest again you read the first 3 paragraphs of section 1 of on the electrodynamics of moving bodies,

Basically relativity 101, straight from the horse mouth (no disrespect to the great man )
Mm