Time

[fredrik]

I know but I think you have me confused. I am not saying time is this or that, I am trying to ask a question on what time is, and I guess from what you are saying that its general relative to whom you are asking. I think its important that we can correctly define the physical world around us also.

 

I agree with you that we want to understand the world we live in but I think one may need to decide about a starting point.

 

I'm not suggesting that the concept of time is completely arbitrary.

 

I suggesting that the choice of units of time is a convention or choice but that the direction of time so to speak, can be given a probabilistic interpretation. In this interpretation time is defined in a context, which means there is a specific observer which possess a specific set of information about the world. Without this "context", time is ill defined as far as I understand.

 

*This is formally speculative* but in my personal opinion, by a similar token, space can probably be built as well. Starting with one dimension, the second may evolve, and finally the third dimension can evolve as a way to resolve noise in the lower dimensions. In this respect, time and space can be said to have similar origins.

 

Unfortunately it's hard to explain this without starting out with alot of definitions and constructs. I personally think it's a bit intuitive, but it all depends on your philosophy. It is fundamentally incompatible with the old deterministic ideals. Everything I have tried to explain is based on probability theory and the world on microscopic levels is sort like just chaos.

 

Anyway, good luck in your quest. I sometimes think we all have to find our own asnwers to our own questions. Keep looking and the progress is unavoidable.

 

/Fredrik

[Klaynos]

Fredrik the thing with good science is that it doesn't depend on your philosophy at all.

[fredrik]

Fredrik the thing with good science is that it doesn't depend on your philosophy at all.

 

I was mainly referring to intuitive human understanding beeing dependent on philosophy, and evolution of science in a certain sense beeing philosophy dependent. Not that a certain philosophy is required, but rather that the philosophy can make it more, or less, natural.

 

Perhaps we disagree here?

 

Of course, it is possible to define the terms better, and use a highly formal and less ambigous language here. But then it gets cumbersome for a forum and not everyone would follow the abstractions anyway. Sometimes the main message can be propagated without math. Then calculations have nothing to do with philosophy of course, which is why computers can successfuly do it.

 

But devising the calculations is another story IMO.

 

/Fredrik

[Farsight]

That's how we define time. That's not necessarily the representation of what time actually is. Without a meterstick, we'd still have spatial dimensions. They exist regardless of how we measure them. You cannot argue the nonexistence of a time dimension based on the ways it is measured.

 

The word dimension originally meant "to measure out", Cap'n. Temperature used to be considered a dimension, when the word was used to talk about anything you could measure. But there's a huge difference between this sort of dimension and the sort that offers freedom of movement.

 

If you have no freedom of movement within a "dimension", you really shouldn't put it in the same camp as those where you do. Hence people talk about 3+1 dimensions rather than 4 dimensions.

 

I'm not arguing for the nonexistence of time. Time exists like heat exists, as a derived effect of motion. We talk about heat flowing, and that's reasonable because there's a spatial motion going on. But there's no actual height to a high temperature, there's no motion through heat. In similar vein there's no actual length to time, and no motion through time. These are just concepts we grew up with, and find difficult to analyse.

 

If you boil down what I'm saying, my view is basically that Time Travel is impossible. But sadly my full explanation is rather dismissed as speculation.

[Klaynos]

If you boil down what I'm saying, my view is basically that Time Travel is impossible. But sadly my full explanation is rather dismissed as speculation.

 

You know I can't imagine why?

 

In the 4-vector why would you consider that time appears along side the 3 space dimentions?

[Edtharan]

If you have no freedom of movement within a "dimension", you really shouldn't put it in the same camp as those where you do.

In a black hole you will always fall into the centre, that is you have no freedom of movement in the direction away form the centre of the black hole (by the way, if you had freedom of movement in that direction, then you could leave the black hole). So, does this mean that the dimension that points away form the centre of the black hole doesn't exist?

 

Lack of freedom of movement is not the criteria that determines if a dimension is physical or not and it never has been.

 

You can not just arbitrarily redefine what constitutes a physical dimension just to make your theories fit.

 

A physical dimension is one that is effected by physical phenomena and can in turn effect physical phenomena.

 

Time exists like heat exists, as a derived effect of motion.

But to measure motion you need time.

 

If we take Time as a non physical dimension (that is derived from motion like heat is derived from atomic motion), then how can we measure motion.

 

Without Time as a physical dimension, then every thing must occur simultaneously. If I have a ball, then where it starts and where it stops (and every point in between) are simultaneous.

 

Imagine photographing this with balls on a pool table. If you take a long exposure, you will get the equivalent. You will effectively remove time and make the position of the ball simultaneous along it's entire path.

 

Now, solely from the photo, can you determine the velocity of that ball? No. You can work out how far it moved (displacement). However, you need to know how much time the ball took to move the distance shown. You need time. You can not have motion without time. Time can not be derived from motion.

 

So one second is circa nine billion little atomic events' date=' and the word "radiation" tells you these events are associated with light. If these events didn't happen, and nothing changed, you'd have nothing to count, and there would be no time. The only distance associated with these event is the distance travelled by something electromagnetic within the caesium atom during the event interval. It's a spatial distance, not a time distance. Hence a light year is a spatial distance, not a time distance. When you realise this you realise that

 

The metre is the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second.

 

..is circular. Both seconds and metres are defined using the distance travelled by light, which is why we always measure c to be the same value. When you say "apart" there's no actual time distance in there. It's just what you grew up with, and it's difficult to think any other way. Really, really difficult.[/quote']

This is a false dichotomy.

 

What you use to measure is not the thing you are measuring.

 

Your first line almost gets it right. IT is measured by around 9 billion events. But it would not matter what those events are. They might be the wobble of the atom, they might have been the decay rate of the electron into a lower shell and not been the count of radiation. Therefore it is not dependant on the light/radiation.

 

The speed of light here is irrelevant. The light might travel 100km/h, but we still could use the 9 billion detected events, it wouldn't make a difference to the number of counts we measure in a period of time.

 

You have created a false argument by implying that the speed of light makes a difference to the number of counts we would receive.

 

Also, what you use to measure is not the thing being measured.

 

The counts of radiation are not time, but the events occur regularly within time. Because the events are regular we use them to signal that a certain period of time has passed.

 

It is the regularity of events that is important. Whether they are pulses of light, the swinging of a pendulum, the bounce of a spring, the rotation of the Earth, etc. It is the regularity of them, not what they are made of. If you get hung up on what the mechanics of the regularity are, then you are making the mistake that what you use to measure is the thing you are measuring.

[fredrik]

But to measure motion you need time.

 

If we take Time as a non physical dimension (that is derived from motion like heat is derived from atomic motion), then how can we measure motion.

 

Without Time as a physical dimension, then every thing must occur simultaneously. If I have a ball, then where it starts and where it stops (and every point in between) are simultaneous.

 

IMO, both time and motion can be devised from the slighly more abstract "change" or uncertainty which is also a connected thing. Because event without time the status quo may be uncertain. The relative change of the clock device to other changes would be a measure of time. Then this can be used to define motion. A valid question is also where the heck does this clock device come from? I imagine that it as a more or less well distinguished substructure.

 

Consider a series of snapshots of our information of reality(fuzzy I know) - can the time ordering be recovered in case someone permuted the shots?

 

Usually the arrow of time reveals itself in that the entropy increases(*). In the case of periodic phenomena

 

So that is a basis for the "direction of change", then we only need to define the units that parametrise our world line along the "direction of change", that's what the clock device is for.

 

One may not object that, like is well known from chemistry, due to kinetical reasons, reactions does not always proceed in the direction of maximum global entropy increase. But what prevents us from entending this statistical reasoning to include the kinetic prior?

 

The state of the system can be considered diffusing into a new state. Diffusion of what within what is the obvious question? But I think of this diffusion as beeing random disturbances in our information state - constrained by our prior informaton (kinetic constraints included).

 

This is an extension to the similarities between of QFT and statistical mechanics, but it seem the full exploit remains to be seen. As has been noted long time ago the QM equations look like diffusion equations, and usually there are some lame supposedly appealing argumentations that suggest you just "replace the Temperauture T in the for 1/it" in he partition function and there you go. This is IMO not convincing. But I think there is a proper way to find the formal connection. I do not have a thourough background in those details to know if someone has worked out this connection satisfactory, but so far I have not see a full treatise.

 

(*) One may wonder, how is it that the macroscopically obvious arrow of time seems to be hard to find in the microscopic scale? A possibility is that at this noisy level, we are unable to see the arrow of time. The arrow of time is just not not distinguishable, and what isn't distinguishable can by definition not have any impact. Accordingly the notion of time at this scale, is either completely random/chaotic, or pointless, which is effectively the same thing.

 

It's hard to explain properly and I wish I had some proper links to supply but I have not seen a single paper that IMO makes a fundamental treatise of this. Some of the modern research papers in quantum gravity tangent on this but it's often unclear for the outsider because a single paper tend to be a small piece belonging to a research program. Which is presented elsewhere. Often the papers also come out at mathematical exercises to someone who isn't deeply involved inthe the specific research program, which I am not either.

 

I have just recently started to attempt a fundamental treatist of this from scratch but it will sure take me some time.

 

Meanwhile I suggest searching "random dynamics". http://www.nbi.dk/~kleppe/random/qa/qa.html is one site which attempts to line out a research program... not the best but OTOH pretty decent overview, that is also clearly a young project.

 

Ariel Caticha http://www.albany.edu/physics/ariel_caticha.htm also have written a series of relevant papers also thouching the subject.

 

For those who don't like that math, the above pages are comparatively readable.

 

I feel like I have written the same thing several times now Do the posts come out as annoying? too much words? to little math? or fuzzy?

 

/Fredrik

[Cap'n Refsmmat]

The word dimension originally meant "to measure out", Cap'n. Temperature used to be considered a dimension, when the word was used to talk about anything you could measure. But there's a huge difference between this sort of dimension and the sort that offers freedom of movement.

I don't care what "dimension" used to mean.

 

If you have no freedom of movement within a "dimension", you really shouldn't put it in the same camp as those where you do.

That's your distinction, not mine.

 

I'm not arguing for the nonexistence of time. Time exists like heat exists, as a derived effect of motion. We talk about heat flowing, and that's reasonable because there's a spatial motion going on. But there's no actual height to a high temperature, there's no motion through heat. In similar vein there's no actual length to time, and no motion through time. These are just concepts we grew up with, and find difficult to analyse.

Right.

 

The concept of time being a dimension fits the data well. So does your idea, but you have no more evidence than the rest of us. You cannot claim to be right more than we can.

[lakmilis]

A good question. Indeed I am in principle agreeing with a seemingly unpopular stance of Farsight, but with perhaps more profound reasons for it. However, this is a physics forum, so the metaphysics of time is bound to be unpopular when one disagrees with the essence of time according to Einstein's adopted Minkowski space and realising time is a dimension.

 

The question though is of paramount importance still and just to state where I am standing; Time is not a quality, it is an observation of one.

 

Having said that, mathematical models work with many things. For example, often people 'explain' here how logical geometry is due to inherent properties of our reality which we observe and deduce from. However, points are mathematical entities, so are lines with no width, our reduction of n-1 dimensions when we try visualising 4-d space , etc. They work, yet it is perfectly legit to also state that they don't exist in real life. (All , ABSOLUTELY ALL *REAL* OBJECTS we are aware of, are [at least] 3 dimensional). 0-2D objects only exist as subsets in our minds (expressed in mathematics on good ol paper

 

I have in my metaphysics a postulate stating a disagreement with the semantics of time in contrary to its quality as a dimension in physics aka GR for example:

 

"Time is the perception of movement".

 

Thus, I say it [time] is an observation of one [a quality] (hardlinking perceptory senses and minds as such) to physical reality rather than being a quality.

 

Here, I am pretty sure this will meet some resistance (and flaming hihi ) but initially and foremost is because it seems like it is saying GR is wrong. Not at all, but I saw one of the admins severin or something, refer to people here as the odd philosophical nut passes by and makes comments. I believe that was a very unhealthy comment as we know that paradigmes in metaphysics often will lead to readjustment of physics, etc. Anyway, giving the benefiot of the doubt it might of been caused by some other heated argument or so.

 

What I am saying to initial poster is that indeed, time is secondary to movement (rejuvenating Aristotle and the old Greek philosophers immensely advanced precognition of principles).

 

So how would this translate in possible 'practical or useful' considerations in current GR for example?

 

I personally am not gifted enough with abilities in maths (yet by all means I still am learning and have some skill) to fly out a revision hypothesis on the topic, how to incorporate this 'rejection' of time as a quality and how it would possibly affect our physical formulas to deal and predict events in space.

 

I am sorry I am being somewhat digressive but this is exactly the work I am involved in on a private and personal level, I call it Epistemological Physics.. But from reading certain threads I believe this forum is more suited for 'current scientific thought' and explanations of these rather than a forum for trying to search for paradigmes

 

I was looking into a 5-D alteration of GR to incorporate this so called postulate of there is movement only, and a substance of sensory capabilities can react ot movement, conceiving duration and displacement, thus perceiving 'time'.

 

I did not manage to derive if a 5-element metric was necessary or not and I due to life commitments, stopped working in philosophy several years ago.

 

This maybe does not help too much, certainly not compared to word count, but I do think that it is healthy to not necessarily take time as a quality (dimension) even if you should employ that understanding in the framework of 3+ D manifolds as today. Like many pointed out, to understand the limitations of a theory , certainly needs understanding of the theory itself.

 

Final note, if I state time is not a dimension but a perception of one, yet talk about 5-D reality, what could the other 2 be?

 

lakmilis

[lakmilis]

Oh I failed to see that post before mine. You two are discussing the semantics of the word dimension, discussing freedom of movement and if temperature is a dimension etc. It seems like it is just a matter of tensor ranks and scalar and vector properties. I am assuming the people involved at least know vector calculus enough to already be able to agree on yoru distinctions..if not, have a look into tensor ranks.