I tend to think that Richard Feynman got this right by calling it philosfuzzy. Physics from its inception has had funny elements to it, starting with my observation about F = ma and the singularity in 1/r^2 forces. Yet progress can still continue. The important thing is whether we can calculate things which reflect the observable world.
Cheer LC
Even progress is a fuzzy concept. We never know if we are just swimming against the tide.
Dear John
Motion (not time) runs in NOW, means in present moment, means in timeless space. We are born, we live and we dy in timeless space.
With cloks/time we measure motion in timeles space. Do not mix change in present with time. Change (motion) is natural physcal event.
Measuring change (motion) with cloks is man made physical event.
The diffrence is essential.
Time is not part of the universe. Time/clock run is a man made device to measure motion in the universe.
yours amrit
amrit,
I think we have a difference of opinion there. The perception of change is conscious, but the effect of change isn't.
Does measuring temperature create the scale of hot/cold?
Admittedly without conscious perception, it is all rather mindless happenstance, but events occur, whether they are seen or not. It would be irrational to assume otherwise.
John
Change cannot produce time.
Time/clock is a measuring tool.
The problem is that we "project" neuronal linear time in the physical world. We see time outside we are not aware that our experience of motion is through time that is inside.
Physics to understand real nature of physical time has to deal with neuronal time first.
Physical time/clock run is a measuring reference system. Not more and not less.
yours amrit
amrit,
I understand you are saying we have a perception of events which inanimate reality is not aware of and it is simply present.
My point is that there are physical processes at work and the effect of time is a consequence of them. If a rock rolls down a hill, it certainly has no material existence outside of the present. There is no metadimension in which it is at the top of the hill and at the bottom of the hill, but there is a process, a continuum of presents, or presence, so that at one point in the past, it was at the top of the hill and now it is at the bottom of the hill.
Let me paraphrase the old Tao koan; If a clock is ticking and no one hears, or sees it, does it still move?
Keeping in mind that the rock does not move into the future, the event of it being at the top of the hill recedes into the past.
Dear John
Yes, great insight. This is the point. Rock rolls and clock "thick" in space only. With clocks/time we measure rolling of the rock.
I need 20 years to get that....there is no time behind motion. Time is only describing motion.
I'm quite emotional in a way peaceful seeing that you got the point. This my vision cost me a lot. For years I was treated as a "strange guy". No one was ready to take me as a student on PhD: "Physical Time is Run of Clocks".
I feel now things are comming ready.
yours amrit
PS
Let me paraphrase the old Tao koan; If a clock is ticking and no one hears, or sees it, does it still move?
If no one sees it or hears it, clocks still move but time not. For time to exist observer is needed.
The problem I see is that physics is not in the business of determining whether model structures exist. In this case geometrical structures such as space and time. Yet, if we are to assume space exists and time does not, then a Lorentz transformation rotates time (which does not exist) and space (which we (or I) am presuming exists) into each other. So some element of something which does not exist gets transformed into something that does. That is a bit silly IMO.
Barbour is of course on the vangaurd of the idea time does not exist. This is due to the Wheeler DeWitt equation, which acts as a timeless contraint. Yet to be honest I think the WD equation has some problems. Also a lot of theory developed along these lines is now in trouble with the Germi Gamma Ray observation of equal speeds of light for different frequencies of radiation.
Cheer LC
I meant Fermi, not Germi LC
amrit,
"If no one sees it or hears it, clocks still move but time not."
Time is just a word. The effect it symbolizes is the changes due to motion. They exist, so time exists as a consequence of motion, not the basis for it. I can understand why you want to say time doesn't exist, because you/we are taught it is that elementary dimension and you realize that doesn't exist. Your problem is that this effect of change is still elemental to the function of life, so people will look at you funny, if you say "time" doesn't exist. If you want them to even think about what you are trying to say, then you have to argue it is different from what they think it is, not that it doesn't exist.
As an effect of motion, it is much more like temperature than space.
Lawrence,
"The problem I see is that physics is not in the business of determining whether model structures exist."
Physics certainly should! Presumably it's about the physical. Blame it on the mathematicians claiming purity of form over messy reality.
"Barbour is of course on the vangaurd of the idea time does not exist."
Then he goes and tries to deduce some unit of time "worthy of the name" from a theory of least action. How can one claim it's an illusion and then, in the next breath propose an irreducible unit of this illusion?
"Also a lot of theory developed along these lines is now in trouble with the Fermi Gamma Ray observation of equal speeds of light for different frequencies of radiation."
That does seem to be significant. It really seems to blow a hole in the effort to quantize everything, including space.
Lawrence, you wrote: Barbour is of course on the vangaurd of the idea time does not exist. This is due to the Wheeler DeWitt equation, which acts as a timeless contraint. Yet to be honest I think the WD equation has some problems. Also a lot of theory developed along these lines is now in trouble with the Germi Gamma Ray observation of equal speeds of light for different frequencies of radiation.
WD equation can be without sign "t". Newton equation for gravity has also no "t". This simply means that gravity is immediate phenomena. Recent research shows they are few phenomena in physics that are immediate, see ma essay.
.......................
John, if you think that motion produces time than you have to prove that. Where is time produced by motion. I do not see it. There is no evidence of such a time. Barbour is right saying time in which events run does not exists.
I do not know exactly his statement regarding "physical time/clocks run".
I see clocks/time fundamental in physics.
yours amrit
Newton's law of gravity has not time, but it has little utility unless used with Newton's second law of motion F = ma. So you have
F = -GMm/r^2
and
a = d^2r/dt^2
put them in F = ma and voila you have a dynamical equation that involves time.
This is different from the WD equation, which is really a constraint equation with Lagrange multiples imposed as the choice of lapse functions.
Cheers LC
Lawrence
In equations "t" is number of numerical order of motion.
For example 5 second, means that clock did 5 thicks.
v = d/t
if you move on distence of 10 metters and clocks thich 5 times this means that you move with velocity of 2m per second.
1. you move in space only
2. clock runs/thicks in space only
3. velocity v happens in space only, time t is only a device to measute it
we measure with clocks numerical order of motion, through inner neuronal time we experience numerical order as duration, but physical events has no duration on its own.
yours amrit
3.
PS At Planck level events happen without clock thicking. They are immediate. As gravity and EPR experiment.
Save it to say I am not convinced of your argument. It might sound "hip" to say that time does not exist but frankly physics is not in the business of saying what model or geometric entity exists or not.
As for the Planck distance, there is lots of confusion about this. It does not mean that space or spacetime are sliced up into these units. It is a length scale which gives a limit on the quantum information available to any experiment.
Cheers LC
amrit,
"Barbour is right saying time in which events run does not exists."
That's right, because the events are not running in time, they are creating time.
"we measure with clocks numerical order of motion"
Exactly. One tick happens and then is no more. Next tick happens and then it too is gone. The only constant reality is the clock.
The linear dimension theory is that somehow, this clock is traveling along the fourth dimension on which these ticks exist, much like pages of a book exist before and after we read them. The reality is that the ticks only exist as they are happening.
Rovelli propose that there is no time on Planck level. How time dissapear at Planck level ? There is no time in the whole universe om micro and macro level.
Time/clock is measuring devivce. Some phemonena happens in time zero. They are immediate. Clock cannot "thick" even a nano second or less and event happens.
This cleraly shows that event does not happen in time as a medium.
This clearly shows that time/clock is a measuring device merely.
For me: TIME = CLOCK RUN
CLOCK RUN = TIME
yours amrit
Again lots of confusion here. The Planck length, or Planck time, and their recirpocal or conjugages as Planck momentum and energy, just represent a cut off in scale beyond which one can't access information. It is the scale where a black hole deBroglie wavelength is equal to the horizon radius or circumference. That is all folks, there is nothing really about time not existing or any such stuff. There is nothing here about any Platonistic idea about things existing or not. Just stick to the basic stuff and not read between the lines of equations to draw philosophical inferences.
Cheers LC
