What is time?

[Little Bang]

Suppose we have a magic ship that can hover at the event horizon of a Bh. When I look back out into space and see photons approaching me I notice they are blue shifted. Their wavelengths are getting shorter. Their clocks ( the distance between peaks ) is getting shorter and that is the ultimate way in which time dilates because the wave will fall toward the center forever and will approach an infinitely short wavelength

[AnssiH]

Michael, I have the feeling you didn't think about anything I said.

Originally Posted by Michael Mooney

I agree with HB, and you, AnssiH have once again avoided the question, "Is time only in our minds, only a semantic debate?"... or is there a difference between clocks keeping time differently under different conditions (forces of acceleration bringing them to different velocities) and "time itself" speeding up and slowing down?

You can do a full page of circumlocution around this question (and you have done several), but you have managed to completely dodge the challenge of "time reification" as a product of subjective idealism.

I would have thought my statement "...yes it does point out explicitly that relativistic spacetime is an ontological concept that is just a matter of defining the data in such and such ways." was pretty explicit.

A rainbow is an observable phenomenon, regardless of what you call it. And science has a very good understanding of the spectral refraction which causes a rainbow. It is not an unknown but a very well understood phenomenon, regardless of the semantics.

It is "very well understood" because there exists a lower-level explanation to it, which is an explanation working in terms of other defined entities, that are also a matter of spotting a familiar pattern. Spacetime is exactly the same; the point is, it is a familiar pattern that has got a name to it. Since you can recognize that its validity does not entail its ontological existence, I would think you could understand the same argument is valid for absolutely any "supposedly ontological thing".

"Time" is a very different ball-o-wax in that clocks obviously "keep time" differently under different and very well understood conditions, yet the jump to "time slowing down and speeding up" is a fallacy derived from the clocks keeping time differently.

You do not, in all your verbosity, address this issue, and as I see it, you don't even realize that you are not addressing this issue.

I think my statement "...But that reading on those clocks is what people usually take as "time", i.e. people take it that the best information we have about time is via measuring it with clocks. And that leads to the idea that "time dilates". Oops." was pretty explicit, but I don't think you even read it.

And I don't expect anyone to understand where that statement is coming from, when it is standing all by itself like that. You have to first understand few underlying epistemological issues (exactly the issues I am discussing prior to that statement)

See, the thing is that I am not talking about an "opinion" about how reality is. I am talking about tautologies, i.e. things that are true by definition, and as such do not tell us what reality is like either. It is just that we have chosen to see things that way.

And the only way for you to actually understand where that issue is coming from, is to actually follow the logical deduction, and there are far too many logical steps involved there for you to be able to comprehend it all at once just by me stating the issue. (Think about scientific deductions in general; they lead to relationships that are not at all obvious from the premise)

I just really would not like people to think I am stating another opinion. See, tautologies between definitions are nice in that they are either logically true or logically false. The problem that people have at seeing this tautology is in that they bluntly skip the issues posed by epistemology and ontology. You are doing exactly that when you insist that we talk about this in terms of the entities that physics has already defined.

So, to "rewind" to a direct challenge you have completely avoided...
please respond to my baseline challenge above :

The only gripe I have with your challenge is that when you let yourself to think about the issue in terms of defined things like "sounds", you will be working with an arbitrary (albeit valid) set of definitions and at that point you have lready missing the circumstance where relativistic time relationships arise.

I am NOT saying world actually is idealistic, try to get around that interpretation.

Is it all semantics and "in our minds" or are there observable "rainbows" (excuse the label... what would you call the phenomenon?).

The issue is not what you call it. The issue is that your definition of a pattern does not mean there is an object with real identity to it over there.

How about a brief and to the point reply for a change.

If you just want a snappy one-liner, I'm afraid I can't help you with that.

-Anssi

[ldsoftwaresteve]

Michael and Hydrogen, we have at least 3 different worldviews coming into this discussion. All of us think ours is correct and that is as it should be.

I believe you have 'time' as the driver of all change. If not, what is your driver?

I partially understand AnsiH's and DoctorDick's and in this discussion they're dealing with the part that time plays in their work with DoctorDick's mathematics. My gut tells me that someday DoctorDick's work will be standard curricula for those who call themselves mathematicians.

My own worldview is radically different from yours. It envisions a Universe that has a single mechanical explanation for all events and if you want more than that, read McCutcheon's book. That book provides a single driver for all events. The conclusion that I came to after understanding what he was talking about is that Time has to be a mental construct and cannot be anything else. I then found that conclusion already in his book although I missed it the first time round.

If he is correct, the universe is much stranger than you might think. I don't claim true knowledge here, I just have a worldview and am expressing one part of it. I also think it is quite self coherent. For one thing, it allows the existence of many worldviews with the understanding that the quality of the worldview is only as good as it works.

[Michael Mooney]

Idsoftwaresteve:

I believe you have 'time' as the driver of all change. If not, what is your driver?

I have always (see "Spacetime" thread) said that time is only the concept of event duration, erroneously reified into being some kind of entity/medium/agent with properties of its own.
This certainly precludes "it" being an actual agent of change, the "driver" you falsely attribute to me (and HB.)

I like a Bang/Crunch cosmology in which all cosmic material/energy/plasma (MEP) actually explodes out into empty space (which *must* be infinite, as any supposed boundary would simply have more space beyond... no "end of space"... an ill-conceived concept.) Then, finally, after gravitational reversal, it all implodes back into the primordial ball of cosmic stuff (MEP) and again explodes in a perpetual great cycle of oscillation.

All this, and all movement (events) in between bangs and crunches happens according to the principles/laws of physics without an agent "time" involved, though, of course, in common language, it all "takes time"... unimaginable billions of years per full cycle.

In all of this we can forget about what our clocks measure, though the whole cycle can be said to "take a very long time" or "have an extremely long 'event duration.'"
The dynamics of each crunch and immediate bang, i.e., the laws of physics involved, are not relevant to this thread (see my "Bang/Crunch Revisited" thread), but "time" is certainly not an agent of change... the "driver" you suggest above.
Michael

[Michael Mooney]

AnssiH:

I would have thought my statement "...yes it does point out explicitly that relativistic spacetime is an ontological concept that is just a matter of defining the data in such and such ways." was pretty explicit.

The basis of my "spacetime" thread was that "it" is falsely assumed to be an "it" with various properties in that "it" expands, contracts, curves,has shape ("flat, curved, etc.) From the git-go, since Einstein/Minkowski, every presentation on relativity makes the above assumptions... "Gravity bends spacetime... etc., etc.

The same error is constantly made regarding "time" and "its" "dilation" etc.
A:

It (a rainbow) is "very well understood" because there exists a lower-level explanation to it, which is an explanation working in terms of other defined entities, that are also a matter of spotting a familiar pattern. Spacetime is exactly the same; the point is, it is a familiar pattern that has got a name to it. Since you can recognize that its validity does not entail its ontological existence, I would think you could understand the same argument is valid for absolutely any "supposedly ontological thing".

"Spacetime" as above is *not* ontologically equivalent to rainbows and sound. What is "lower level" about the laws of physics as applied to the visible spectrum of light as refracted by water droplets at an exact angle of observation relative to the source light? Ditto sound waves. Both are observable (visual and auditory) phenomena... the proper subject of science. "Spacetime" is not. The question "what curves or dilates?" has never been addressed to my knowledge in this forum.
Language simply *denotes* the observable phenomena in each case ("rainbows and sound.") The observable phenomena which "spacetime" presumes to denote is that the trajectory of "objects" (real masses and actual light) bends around gravitational generators (masses.) The latter is true without "inventing" a mythological "fabric" which bends/curves. This was my constant assertion throughout the "spacetime thread.

A:

"I think my statement "...But that reading on those clocks is what people usually take as "time", i.e. people take it that the best information we have about time is via measuring it with clocks. And that leads to the idea that "time dilates". Oops." was pretty explicit, but I don't think you even read it."

So, without clocks (as in my often repeated thought experiment) what is time? The cosmos still moves the same without "clocks measuring time."
This is the difference between "what exists," ontologically speaking,... the cosmos in constant motion... and the concept of event duration... as in "How long (in arbitrary units of time) does it take this or that *designated* event to happen?" Surely you can't equate the above *concept of time* with the actual observed events (stuff moving around in space.) No doubt that clocks keep time differently under different circumstances. The error is in the leap to reifying time as an entity "itself" with the property of malleability we call "dilation."

A:

"And I don't expect anyone to understand where that statement is coming from, when it is standing all by itself like that. You have to first understand few underlying epistemological issues (exactly the issues I am discussing prior to that statement)

See, the thing is that I am not talking about an "opinion" about how reality is. I am talking about tautologies, i.e. things that are true by definition, and as such do not tell us what reality is like either. It is just that we have chosen to see things that way."

...Like the issue of the ontological difference between the concept of event duration and the perpetual movement of "all things" (observable phenomena) in the world/cosmos... an issue which you have not yet addressed since you lump it all together as all about definitions related to patterns of perception.
That the trajectory of moving "objects" (not the word but the masses it denotes) curves around other massive objects is "true" in a sense that "spactime is curved by massive objects" is not established as true... the latter being a mental invention and the former being directly observable. Do you see the difference? The latter is a theory/opinion as to what makes such trajectories curve. That they curve is directly observable, not opinion or theory.

A:

"And the only way for you to actually understand where that issue is coming from, is to actually follow the logical deduction, and there are far too many logical steps involved there for you to be able to comprehend it all at once just by me stating the issue. (Think about scientific deductions in general; they lead to relationships that are not at all obvious from the premise.)

Do you see the logical consistency in what I have just written. I think you are creating a smokescreen of complication which effectively obfuscates the issue at hand... "what is time?"
(I do get that "perceived patterns" get labeled according to ones focus and perspective and different perceptions and contexts get different labels as "objects" and all manner of confusion arises then in communication about whatever subject.)

A:

"I just really would not like people to think I am stating another opinion. See, tautologies between definitions are nice in that they are either logically true or logically false. The problem that people have at seeing this tautology is in that they bluntly skip the issues posed by epistemology and ontology. You are doing exactly that when you insist that we talk about this in terms of the entities that physics has already defined."

That "objects" are all about perceived patterns, definitions, and internal consistency of related epistemology *is* "your opinion!"

Science *does* understand "sound" and "rainbows" in a very "sound" way, unlike all this confusion involved in reifying "time." Yet you paint it all with the same broad brush.

A:

"The only gripe I have with your challenge is that when you let yourself to think about the issue in terms of defined things like "sounds", you will be working with an arbitrary (albeit valid) set of definitions and at that point you have lready missing the circumstance where relativistic time relationships arise.

I am NOT saying world actually is idealistic, try to get around that interpretation."

Like I said, "sound" simply *denotes* an actual compression of air into "waves." I'm speaking of the actual manifest phenomenon. If you deny that, we can not do science and "idealism" *does prevail* as a philosophy which precludes meaningful science. You can not ontologically equate that phenomenon (or the actual spectral refraction... *called* a rainbow... call it what you will)... with malleable time and space and "spacetime."

There is an ongoing debate in science on "the ontology of spacetime" but none on "What is sound... or spectral refraction, really?"

A:

"The issue is not what you call it. The issue is that your definition of a pattern does not mean there is an object with real identity to it over there."

When a rainbow *appears* the dynamics of spectral refraction, at a precise angle to the sun *is happening* regardless of anyones definition of it as a subjectively perceived "pattern." A whole group of people often pause to admire "the same rainbow" and they have no problem with its "identity" as an object, and we all know that "the ends of the rainbow" touch down on the ground at different places according to different points of observation... or as we drive along.

I am getting bored with your denial of the above, and the whole principle involved. Can we meaningfully identify what we see as a rainbow? Yes, of course. And the tree falling as a "sound", likewise.
But how 'bout that magical fabric "spacetime?" Well, there the debate begins.

A:

"If you just want a snappy one-liner, I'm afraid I can't help you with that."

No, not a one liner... just direct reply to the issues/challenges I have raised. Since it has not happened yet, I doubt that it will.

I call stalemate.
Michael

[Erasmus00]

Originally Posted by Michael Mooney

From the git-go, since Einstein/Minkowski, every presentation on relativity makes the above assumptions... "Gravity bends spacetime... etc., etc.

Not an actual development of the theory! Popular descriptions of the theory, which don't assume a mathematical background of the reader, do not start with any assumptions about time. They start with physical postulates (laws of physics are the same regardless of coordinate choice, the speed of light is constant) and the implications for the nature of time follow from those.

You have never studied the theories you are criticizing and as a result, you are arguing against a straw man.

[AnssiH]

Originally Posted by Michael Mooney

"Spacetime" as above is *not* ontologically equivalent to rainbows and sound. What is "lower level" about the laws of physics as applied to the visible spectrum of light as refracted by water droplets at an exact angle of observation relative to the source light? Ditto sound waves. Both are observable (visual and auditory) phenomena... the proper subject of science. "Spacetime" is not. The question "what curves or dilates?" has never been addressed to my knowledge in this forum.
Language simply *denotes* the observable phenomena in each case ("rainbows and sound.") The observable phenomena which "spacetime" presumes to denote is that the trajectory of "objects" (real masses and actual light) bends around gravitational generators (masses.)

"real masses" and "actual light" is just a statement of faith upon certain defined patterns existing "for real" exactly how you have defined them. If one assigns identity to a wave on a water, you would take that as a confusion. But the definition that yields a way to point at a water molecule, you'd take to be ontologically correct, without objective proof.

That is common mistake, but also commonly discussed on the field of ontology and epistemology, and if you don't know what I am talking about I guess there's no need to push this topic further. (If you did, you would come to see the parallels to definition of time, and certainly to "reification of time")

So, without clocks (as in my often repeated thought experiment) what is time? The cosmos still moves the same without "clocks measuring time."

Indeed, but there is much more to it (to the issue of "what clocks actually do", as oppose to measure "time"), if you cared to look.

The reason people fight you on that point is that they don't see an alternative explanation, and indeed no trivial explanation exists. But, there is an explanation that just requires some thinking from the reader. (And it is not an argument about hypothetical ontology)

I do not understand your reluctance to look at it, since it would explicitly prove your argument (albeit via very different route than you expect)

The latter is a theory/opinion as to what makes such trajectories curve. That they curve is directly observable, not opinion or theory.

There is no such thing as "directly observable", as each person interprets the same pattern differently. What you see is what you've defined; that is why people fight you on that issue about "what curves"; they simply interpret it differently (and as far as I can see, their interpretation is more self-coherent, mind you, unless there is something else you've defined differently in your worldview to yield self-coherence, but I have not seen you communicate that difference, AND it would be very painful for me try and figure out whether all your definitions together are valid... that is not as simple ordeal as you might think... :P )

EDIT: Note that the reply from Erasmus just above this post is a result of him being able to trivially see that the definitions you've given, as an explanation to so-called "time dilation", are not enough to "make the ends meet"; i.e. it's not that he's absolutely decided that spacetime exists (I think), it's just that your definitions don't yield the results they'd need to, at least not the way you've stated them (at least not as far as I can interpret your statements).

If you are not able to state a self-coherent set of definitions, that yield the necessary relationships, then you cannot convince a thinking person of your beliefs. (And I call them beliefs because I'd still take that as "yet another self-coherent model about the same raw data"; quite many already exists!)

That "objects" are all about perceived patterns, definitions, and internal consistency of related epistemology *is* "your opinion!"

That is very thoughtless statement from you. I have stated many times, that I do not claim any specific ontology. What I am doing is grant the possibility that our definitions are not aligned with ontological nature of reality, even when they lead to valid predictions. I.e. I am saying I'm not certain that my worldview is ontologically correct, while you are of the opinion that certain entities in your worldview are also ontological things.

I.e. if I state "You cannot be absolutely certain about your beliefs regarding reality", is that an opinion, or a statement of fact? Think about that.

If you grant that is a valid statement, all the additional assertions that I've said to be consequential to that premise, are entirely tautological to it; whether those assertions are valid are not a matter of opinion either, they are a matter of logical consequences being valid (and that can be investigated)

I call stalemate.

Well I don't find it in any way important to drive this point home to you, I just thought I'd give a little helping hand if you are interested of actually looking at the issue in exact scientific means. (and none of that is meant to defend spacetime ontology, or any ontology)

-Anssi

[Michael Mooney]

More tomorrow... it is late.
but, re:\

(and none of that is meant to defend spacetime ontology, or any ontology)

Is any of your contribution to this thread meant to address the topic question as if there were a "definitive" answer to whether "time" exists in nature or only in human minds, i.e., as an artifact of "clocking" the 'flow of now?'

I challenge the assumed "reality" of "spacetime" and the "time" component itself, as the subject of this thread, as a supposed "entity"... ontologically existing as something with certain properties in and of itself.

Are you aware that this is the question at hand in this thread? You are so into your (paraphrasing) 'it's all subjective... we can't know anything for sure' philosophy (just short of absolute idealism) that the discussion of evidence for and against "time as an independent entity" can not even carry on here.
Do you see why I call this a stalemate?
I'd still like others to join in, not intimidated by your philosophy.
Michael

[dkv]

Time is like an explosion which slows down on observation.

[Boerseun]

"Space", "Time" and "Spacetime" is in no way analogous to "light" or "sound". Neither light nor sound can exist or propagate in the absence of space and time. Sound waves are pressure waves of particles bumping against each other and making your ear drum vibrate. It is not possible without space to vibrate in, or time in which to propagate.

But you know this. I'm not talking down to you, I'm just illustrating the point that space and time is fundamental, and cannot be described in any other way but saying "space is space" and "time is time".

A traveller taking off with a clock and a measuring tape takes off after having synchronized his timepiece with his friend. He goes flying at relativistic speeds around the sun a few times, and does very careful measurements of the inside of his spaceship, and the ticking of his clock. His buddy on Earth does exactly the same in his absence. In all the time he's away, the inside of his spaceship measures exactly the same according to his measuring tape. It changes not with an inch. His clock ticks away, at a perfect one second per second. He does not measure any change in the flow of time nor the length of a centimeter. Same with his buddy on Earth. Now, once he gets back on Earth, there's a problem. His clock is out of whack with his buddy's clock. How did this happen?

But you know that, too.

So - once again, this brings us back to what the essence of time and space might be that is malleable. Easy. It is "time", and "space". And no, this is not a cop-out, nor is it smoke and mirrors of any kind or degree. The clocks clearly show that time has passed slower for the guy in the spaceship. Yet, he was not aware of that fact. Any "clock" he had with him would read the same thing, be it a wind-up Timex or a piece of radioactively decaying material. He was as well not aware of any relativistic dimensional contraction, because he was in the frame of reference of what contracted. If his dimension contracted to 1mm in the direction of travel, he would not have noticed it. He would look as perfectly shaped as he ever was, because everything that he uses to measure that contraction, have contracted too, because they exist in that space that contracted.

But you know this, too.

It just seems important to re-state the obvious. Because there is no way in which to define space or time other than in terms of itself.

Space is fundamental.

Time is fundamental.

If you're dead-set on defining space and time other than in terms of itself, then you are looking for the underlying elements of space and time, which would be even more fundamental. But I figure you'll end up running in circles around your own argument, because both space and time is fundamental.

Good hunting, Mike.