Originally posted by Bosse de NageNo, not neccesarily, no.
OK, so two-dimensional doesn't mean 'flat'.
The question is - How many coordinates do you need to point out every point on the surface. Two is enough. Thus two dimensional.
This is the easy answer. I'm sure things could be far more complicated...
Originally posted by Bosse de NageNo, I'm addressing the easiest issues first. As the article didn't clarify the context of those quotes I'm having trouble following it up. Was it an interview? Taken from a paper?
De Witt's letter dates from 2001, Folger's article 2007. Things may have moved on in the interim. Besides, no physicist owns their equations.
Apart from all that, you specifically said you would look into Rovelli before.
I get the sense you're just trying to shut this whole thing down in a fairly close-minded way. Do me the favour of proving me wrong.
Originally posted by AThousandYoungHere is a summary of Rovelli's views, by Rovelli:
No, I'm addressing the easiest issues first. As the article didn't clarify the context of those quotes I'm having trouble following it up. Was it an interview? Taken from a paper?
'Forget Time', by Carlo Rovelli
http://fqxi.org/community/forum/topic/237
Enjoy the read! I hope you get something from it. Never mind about this thread ...
I suspect that the significance of time "disappearing" in the WdW equation is that the time is irrelevant; the equation holds for all times.
Energy divided by force is mass. Force is defined partially in terms of time, but in the equation time "disappears" (cancels out). Does this mean time doesn't exist because of the relationship between energy and force? Of course not. The relationship is simply irrelevant to what time it is.
I suspect it's something similar.
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Originally posted by Bosse de NageThe notion of time
Here is a summary of Rovelli's views, by Rovelli:
'Forget Time', by Carlo Rovelli
http://fqxi.org/community/forum/topic/237
Enjoy the read! I hope you get something from it. Never mind about this thread ...
familiar to us may then be reconstructed in special physical situations, or within an approximation, as is the case for
a number of familiar physical quantities that disappear when moving to a deeper level of description (for instance:
the “surface of a liquid” disappears when going to the atomic level, or “temperature” is a notion that makes sense
only in certain physical situations and when there are enough degrees of freedom.
This implies time does exist, but only as one manifestation of some deeper law. Basically what I said earlier with respect to Newton's Laws and temperature.
In the formalism of general relativity, we can distinguish different notions of time. In particular, we must distinguish
the coordinate time t that appears as the argument of the field variable, for instance in gμ(x, t), from the proper
time s measured along a given world line
A big hint that the confusion here likely results from the Fallacy of Equivocation, where definitions are carelessly swapped in the middle of an argument.
the evolution equation predicts all the possible events, namely all the allowed
correlations between the observables, in any subsequent measurement.
Notice that this language makes no reference to a special “time” variable.
I'm boggled by the concept of making predictions while saying time doesn't exist.
I think this guy is fascinated with the fact that there is no "correct" frame of reference, that there are infinite possible frames of reference which all experience time differently. However simply because no one frame of reference has the "correct" time doesn't mean time doesn't exist. The time of any frame of reference has a specific relationship to the time of any other that can be mathematically calculated; this reality does not mean that there is "no time" but rather that equations will give the correct answers no matter which frame of reference's time you choose to use for the calculation - as long as you keep the frame of reference consistent.
The time of our experience is associated with a number of peculiar features
that make it a very special physical variable. Intuitively (and imprecisely) speaking, time “flows”, we can never “go
back in time”, we remember the past but not the future, and so on. Where do all these very peculiar features of the
time variable come from?
I think that these features are not mechanical. Rather they emerge at the thermodynamical level. More precisely,
these are all features that emerge when we give an approximate statistical description of a system with a large number
of degrees of freedom.
Yep, like I thought. He's defining time as something requiring statistical analysis of large systems. Well of course it won't exist in small systems in that case.
Therefore, in a statistical context we have in principle an operational procedure for determining which one is the time
variable: Measure 0; compute H0 from (16); compute the hamiltonian flow s(t) of H0 on : the time variable t is
the parameter of this flow.
Well there you go. The time value exists; it is "the parameter of this flow".
Later on he makes other references about what time really is in his mathematical model.
The thermal time hypothesis. In nature, there is no preferred physical time variable t. There are no
equilibrium states 0 preferred a priori. Rather, all variables are equivalent; we can find the system in an
arbitrary state ; if the system is in a state , then a preferred variable is singled out by the state of the
system. This variable is what we call time.
I can't say I deeply analyzed the math here, though I do have some familiarity with this level of math. However I am not convinced that "time does not exist" is in any way an accurate description of what Rovelli is saying in this paper.
Originally posted by Bosse de NageNo it doesn't. In fact it is interesting to note that under General Relativity, three dimensional space is not 'flat' either.
OK, so two-dimensional doesn't mean 'flat'.
There are a number of consequences to a proper understanding of dimensions:
1. A finite single dimension can be continuous.
2. A circle is also a straight line.
3. Straight lines may cross at more than one point.
Originally posted by AThousandYoungAs I said, 4.a. is more general and includes 5.
No, mass does not in any way define a point. You were using Definition 5.
I know what a space is. I've studied quite a lot of physics and math.
But you clearly don't understand what is meant by 'a space' in 4.a
The set of all possible masses is 'a space'.
Are you suggesting "southness" is one of the two polar coordinates needed to define a point on a sphere of fixed radius?
Yes.
If so, you might want to consider that
Any spherical coordinate triplet specifies a single point of three-dimensional space. On the other hand,
every point has infinitely many equivalent spherical coordinates.
http://en.wikipedia.org/wiki/Spherical_coordinates
The equator is not just halfway to the south pole. It's also 3/2 of the way to the south pole, and 5/2 of the way, and 7/2 of the way, forever and ever...infinitely.
And your point is?
Originally posted by twhiteheadWhich is why I think it is bunk when it suggests such things.
No it doesn't. In fact it is interesting to note that under General Relativity, three dimensional space is not 'flat' either.
There are a number of consequences to a proper understanding of dimensions:
1. A finite single dimension can be continuous.
2. A circle is also a straight line.
3. Straight lines may cross at more than one point.
Kelly
Originally posted by KellyJayYou think it bunk because you don't understand it. You would do better to simply say you don't understand it. Your decision to think it bunk is equivalent to thinking Greek is bunk just because you don't speak Greek.
Which is why I think it is bunk when it suggests such things.
Kelly
Originally posted by twhiteheadI think it bunk when you have to do away with reality to make it work.
You think it bunk because you don't understand it. You would do better to simply say you don't understand it. Your decision to think it bunk is equivalent to thinking Greek is bunk just because you don't speak Greek.
If you can accept a straight line and a circle are the same thing you can
accept anything.
Kelly
Originally posted by KellyJayYou simply don't understand what I mean by 'straight line' and are convinced for some reason that only your understanding of the word is correct and all else is bunk.
I think it bunk when you have to do away with reality to make it work.
If you can accept a straight line and a circle are the same thing you can
accept anything.
Kelly
The problem you have that the only straight line you can accurately describe that fits your conception of it is the one in the Cartesian plane. The real world is not so nice. There is no reasonable way to define a straight line in the real world that does not result in the phenomena I listed. You don't like that, so you call it bunk rather than face reality.
Originally posted by twhiteheadKM ---Afterall , all that we really know is that the time we experience in this universe started 12 billions years ago.
Once again, it is [b]not an assumption it is by definition. I define time as a dimension and if anything can be placed in relation to anything else within that dimension then that object exists within the time dimension - not outside of it. But I don't know why I bother with this as you refuse to read up on dimensions and understand what they are all ...[text shortened]... . So no it is up to you to explain why you are so categorical about the bigger TIME.[/b]
WHITEY- How many times must I correct you on that? We do not know that. Not in the slightest. We can only speculate.
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Oh , come on , for the purposes of the debate are we not assuming as fact that the Big bang did happen the way science describes? My point is that assuming the Big Bang was proven then we would still only know about the time we experience in this universe and nothing else could be definitively said.
Originally posted by twhiteheadHowever, I am proposing a hypothesis in which time itself is finite ie it started at the singularity of the big bang. It is only a hypothesis and is not supported by any evidence, but neither is it ruled out by any evidence. Knightmeister claims it is illogical, but has not been able to explain why in a clear enough way for any of us to understand.
I am perfectly aware that observable time may be limited - I don't know if it is or not, I don't think we know enough to make that call.
However, I am proposing a hypothesis in which time itself is finite ie it started at the singularity of the big bang. It is only a hypothesis and is not supported by any evidence, but neither is it ruled out by any evid ...[text shortened]... gical, but has not been able to explain why in a clear enough way for any of us to understand.
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The reason why it's illogical to me is because it seems highly unlikely that time would just "start" for no reason whatsoever out of nowhere and nothing.
The philosophical question is why would time just......."start" ? It would be like finding a big tomato plant growing on a dry slab of marble in a sealed marble room. You would just think " how the hell did that tomato plant start in the first place?"
Infact it's much worse than that because it's not just time starting but EVERYTHING. Life just "gets going" somehow.
(BTW- I would be interested in what you mean by time "itself" - to me this suggests some kind of newtonian concept. Bear in mind that I don't think time exists in the way you do. Time to me is just a causal process of events that happen in some sequential order - and we express this as a concept called "time" - What actually exists is matter and energy , there are no dimensions - dimensions are just mathematical descriptions of reality. So to me it seems nonsense to talk about "time itself" beginning because time does not exist - only reality exists. Time to me is not finiyte or infinite - it just isn't anything )
Originally posted by twhiteheadKM SAID ----"For example , why couldn't the "time" in our universe just be surrounded by a larger reality of some sort with it's own "time". All that would be needed would be for our big bang to exist within a larger big bang of some sort. Or even several small big bangs (each with their own "time" ) encased within a large super bang."
Once again, it is [b]not an assumption it is by definition. I define time as a dimension and if anything can be placed in relation to anything else within that dimension then that object exists within the time dimension - not outside of it. But I don't know why I bother with this as you refuse to read up on dimensions and understand what they are all ...[text shortened]... . So no it is up to you to explain why you are so categorical about the bigger TIME.[/b]
WHITEY SAID -"Because it wouldn't be separate 'times' it would all be one large time. If they were separate, then once again, you could not place things relative to each other."
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Basically the universe is a causal sequence of events , yes? Think of it like a large mechanism like an old clock ticking. You can have two or three mechanisms in the same room running at different speeds. A person living inside the clock would experience time moving at a speed that was determined by the energy and efficiency of the mechanism. The clock would be experienced as a closed system of time. Another person in the clock next door might experience something else.
What you fail to see is that time is an expression of the experience we have of events happening in causal sequence. Because we are encased within and are part of causality itself we find it hard to imagine other realities.