What is time? (Again)

[The victorious truther]

Dear scienceforum.net, 

I once tried to include myself in a discussion topic that went under the label of "what is time?" in which many individuals entered with various perspectives either championing the non-existence of time with respect to change (including me) and others who took rather standard interpretations of relativity (special or general) to describe what they mean. I felt that given some of the resources or knowledge i've attained perhaps the discussion could actually go somewhere or be somewhat more productive. 

Over the course of those four years I had realized that philosophy had already been discussing this with already predefined terminology which greatly simplified the discussion so it was easier to see the distinctions being made. Those who were proponents of material/physical change being above time/space (perhaps even making it non-existent or its structures mere abstractions) go under the label of spacetime relationism. Those who are proponents of the distinction of change to time or the existence of time without change  (check out the original Sydney Shoemaker thought experiment) went under the label of substantivalists. A good resource for this discussion can be found here and I also thought the John Earman book "world enough and space-time" outlines the discussion surrounding the philosophical interpretational difficulty of general relativity. 

I'll also note that in the context of special relativity while there is an interpretation of the theory popularized by Minkowski (I believe) and a Lorentz-ether perspective these are both substantivalist interpretations. Ignoring the vagueness surrounding the concept of the ether, the Minkowski interpretations basically amounts to saying that the symmetries we see dynamically come from our one-way interaction with a real existent spacetime that contains said symmetries inherently. The other perspective basically distinguishes between the symmetries inherent in the spacetime itself (in this case i've seen people go with Galilean or Newtonian spacetime) while the transformations dynamically of forces/fields follows special relativistic equations. Basically Loretz-ether theory here could be that newton was only partially wrong about spacetime but especially incorrect about his dynamics. I'm mentioning this because when people try to emphasize change over time they seem to either be under the impression or think they are required to assert that there is some unique simultaneity relation when in reality while you could build one up (a global time in certain solutions of general relativity) it's not required to hold relationism. 

Further, I know this includes philosophy (didn't know exactly where to put it), however, this discussion is fairly close in line with modern forms of physics investigations. Including forms of quantum gravity such as LQG, string theory, or other recent perspectives on quantum mechanics such as relational quantum mechanics. 

So. . . what is time then? What are thoughts given this context? 

Sincerely, college freshman going on sophomore year

[swansont]

22 minutes ago, The victorious truther said:

Further, I know this includes philosophy (didn't know exactly where to put it), however, this discussion is fairly close in line with modern forms of physics investigations.

!

Moderator Note

You posted this in physics, so please confine your discussion to physics. If you want to discuss philosophy, post in philosophy.

 

[MigL]

So far your comments have been mostly Philosophical in nature.
Physicists don't care whether time is 'real' or not.

It is a useful variable, like extension in the spatial dimensions, linear and angular momentum, etc., that helps us define rates of change, and other aspects of the models we build to account for observations, and make predictions regarding 'reality' ( whatever that may be ).
Without it we could not build our models, so it is certainly useful.
We leave whether it's 'real' or not, to the Philosophers.

[michel123456]

9 hours ago, MigL said:

Physicists don't care whether time is 'real' or not.

 

IMHO it is an error, they should care.

Beginning with something simpler: Is space "real"?

[Strange]

32 minutes ago, michel123456 said:

IMHO it is an error, they should care.

Why?

”real” is not measurable or testable so it is irrelevant to science.

 

33 minutes ago, michel123456 said:

Beginning with something simpler: Is space "real"?

You need to define what you mean by “real” and by “space”. In other words, that is philosophy and therefore off topic.

[swansont]

!

Moderator Note

Yes, off-topic. This is victorious truther’s thread. 

michel123456, you have literally dozens of threads where you’ve raised similar objections. Stick with those, and stop hijacking other members’ discussions. 

 

[StringJunky]

Why do people overthink time when it is merely another parameter of the universe?

[Phi for All]

2 hours ago, StringJunky said:

Why do people overthink time when it is merely another parameter of the universe?

I think lots of folks believe there is some fundamentally game-changing yet blindingly simple physical explanation that all of science is overlooking, an explanation that will shed light on all the things we still don't understand. I also think pop-sci authors often try to make time seem enigmatic and baffling, perhaps in an effort to say, "Hey, not even the experts understand this stuff, so you should take a shot and keep reading!" Time might seem like a good place to start for someone without a lot of science background to easily make a massive contribution to humanity. 

[StringJunky]

3 minutes ago, Phi for All said:

I think lots of folks believe there is some fundamentally game-changing yet blindingly simple physical explanation that all of science is overlooking, an explanation that will shed light on all the things we still don't understand. I also think pop-sci authors often try to make time seem enigmatic and baffling, perhaps in an effort to say, "Hey, not even the experts understand this stuff, so you should take a shot and keep reading!" Time might seem like a good place to start for someone without a lot of science background to easily make a massive contribution to humanity. 

Yes. It is also as though some think it has an autonomous existence.

[Phi for All]

1 minute ago, StringJunky said:

Yes. It is also as though some think it has an autonomous existence.

We've already landed probes on asteroids hundreds of millions of miles away using our "flawed" concept of time. I'm not sure that's possible if we have it wrong, not even by a little bit.

6 hours ago, michel123456 said:

IMHO it is an error, they should care.

I think the kind of "care" you're talking about is far too subjective for science. We observe that our models using spacetime coordinates are accurate to an astonishing degree, so to argue against our own best observations suggests we aren't viewing the problem with an objective eye. 

 

[Area54]

21 hours ago, The victorious truther said:

So. . . what is time then?

I go with Professor Wheeler's position: Time is what prevents everything from happening at once.

[iNow]

“[Time] is one of those concepts that is profoundly resistant to a simple definition."  ~C. Sagan
 

[michel123456]

So that puts us back to square zero.

 

[Eise]

1 hour ago, michel123456 said:

So that puts us back to square zero.

I think you should have written: this puts me back to square zero.

Why do you think the concept of time is a problem, given the reaction of Phi for All, or to add some relativistic examples: particles running in the LHC with near light speed, GPS in which they must account for time corrections for the speed of the satellites and for the difference in gravity between the satellites and the earth's surface?

Given all the empirical proofs of special and general relativity, why should physicists go back to square zero?

The only topic I see where physicists have no definite (i.e. no consensus) answer concerning time is the arrow of time. Not all physicists seem to accept the explanation of 'the direction of time is the direction of increasing entropy'. But that has no impact of the practical use of the concept of time in all our technologies.

[michel123456]

42 minutes ago, Eise said:

I think you should have written: this puts me back to square zero.

Why do you think the concept of time is a problem, given the reaction of Phi for All, or to add some relativistic examples: particles running in the LHC with near light speed, GPS in which they must account for time corrections for the speed of the satellites and for the difference in gravity between the satellites and the earth's surface?

Given all the empirical proofs of special and general relativity, why should physicists go back to square zero?

The only topic I see where physicists have no definite (i.e. no consensus) answer concerning time is the arrow of time. Not all physicists seem to accept the explanation of 'the direction of time is the direction of increasing entropy'. But that has no impact of the practical use of the concept of time in all our technologies.

So why is it so difficult to answer the OP's question?

[Eise]

1 hour ago, michel123456 said:

So why is it so difficult to answer the OP's question?

Because physicist don't bother, as long a they have perfect operational definitions of time. The question 'What is time?' is, as already remarked, a philosophical question. Not a question about physics. I think even you have no problem to understand what the traffic sign '50 km/h' means. Really, physicists have no problem with their 'dx/dt', or whatever changes according to t. And there are already several threads about time, and I think most of them in the philosophy-forum, where it belongs.

[swansont]

7 hours ago, michel123456 said:

So that puts us back to square zero.

 

!

Moderator Note

It tells you that you are on the wrong playing board.

If you aren't discussing physics in this thread, you are off-topic.

 

[joigus]

10 hours ago, Eise said:

Because physicist don't bother, as long a they have perfect operational definitions of time. The question 'What is time?' is, as already remarked, a philosophical question. Not a question about physics. I think even you have no problem to understand what the traffic sign '50 km/h' means. Really, physicists have no problem with their 'dx/dt', or whatever changes according to t. And there are already several threads about time, and I think most of them in the philosophy-forum, where it belongs.

I was about to talk about operationalism and how important it is and how many speculators forget that. Connection with what you would do in a laboratory is essential. You saved me some work. +1.

[The victorious truther]

On 7/11/2020 at 6:31 PM, MigL said:

So far your comments have been mostly Philosophical in nature.
Physicists don't care whether time is 'real' or not.

It is a useful variable, like extension in the spatial dimensions, linear and angular momentum, etc., that helps us define rates of change, and other aspects of the models we build to account for observations, and make predictions regarding 'reality' ( whatever that may be ).
Without it we could not build our models, so it is certainly useful.
We leave whether it's 'real' or not, to the Philosophers.

Physicists should care whether their exists time without change as this would seem to influence what sorts of quantum gravity/spacetime they are desiring to investigate (background independent vs. dependent). Though, it's not as simple as declaring it's 'real' or not as a mirage is certainly a rather 'real' experience to those who experience it and only an eliminative materialist would deny that you were having said experiences. Nobody would or does deny this but it's the conclusions we would make from such an observation that would play into deciding the truly important physical background that gave rise to it. In this case there aren't palm trees and a lake out there in the distance but this is merely a perceptual effect that tricked your brain which has been devoid of proper hydration to short cut even rather distant imagery to something familiar. 

I would think that to develop newer models and relay such ideas to the greater public they would make sure to choose their words rather carefully. 

On 7/11/2020 at 5:22 PM, swansont said:

!

Moderator Note

You posted this in physics, so please confine your discussion to physics. If you want to discuss philosophy, post in philosophy.

 

If it's possible to move this to that section please feel free to do so. 

On 7/12/2020 at 10:30 AM, StringJunky said:

On 7/12/2020 at 10:25 AM, Phi for All said:

I think lots of folks believe there is some fundamentally game-changing yet blindingly simple physical explanation that all of science is overlooking, an explanation that will shed light on all the things we still don't understand. I also think pop-sci authors often try to make time seem enigmatic and baffling, perhaps in an effort to say, "Hey, not even the experts understand this stuff, so you should take a shot and keep reading!" Time might seem like a good place to start for someone without a lot of science background to easily make a massive contribution to humanity. 

Yes. It is also as though some think it has an autonomous existence.

I think much of this thought comes straight from pop-science authors and possibly even mainstream textbook interpretations of special relativity which exclaim the separate existence of this Minkowski spacetime from matter that bends or warps depending on your particular frame of reference. 

On 7/13/2020 at 5:51 AM, Eise said:

On 7/13/2020 at 4:31 AM, michel123456 said:

So why is it so difficult to answer the OP's question?

Because physicist don't bother, as long a they have perfect operational definitions of time. The question 'What is time?' is, as already remarked, a philosophical question. Not a question about physics. I think even you have no problem to understand what the traffic sign '50 km/h' means. Really, physicists have no problem with their 'dx/dt', or whatever changes according to t. And there are already several threads about time, and I think most of them in the philosophy-forum, where it belongs.

Certainly some physicists do not. Such as Mach who tried to give an operationalist but failed abandonment of mass in classical physics by using the time integrated newtonian third law. Though, I find it rather strange we would shove such discussion far away from physics as in terms of certain theories (such as special relativity) its the pet philosophical interpretation popular with news organizations or well known physicists that got me interested in researching the philosophy here behind it. It's the philosophical interpretations that books, media, or even introductory material on the subject don't (pardon my language) shut up about that concerns me and yet were going to discuss it far away from physics?

Edited July 15, 2020 by The victorious truther

[jajrussel]

I have always liked this question. The challenge seems to be in being as succinct as possible, and leaving no doubt that as defined it is not a Philosophy, so for the umpteenth and hopefully final time, I’ll try again. 🤔

Time is a physical dimension where all aspects defined by an observer reveal a rate of change.

[Eise]

2 hours ago, The victorious truther said:

Physicists should care whether their exists time without change as this would seem to influence what sorts of quantum gravity/spacetime they are desiring to investigate (background independent vs. dependent).

I think every science has periods of reflection on their basic concepts. But the need for that should normally come from, in this case,  the physicists themselves. If they get stuck in the progress of understanding of nature, if they are confronted with anomalies or inconsistencies in (or better between) their theories, or get stuck in trying to encompass more phenomena in one single theory, it is time to reflect on what they are doing, which includes reflecting on fundamental concepts they use, like time. Some might feel the urge earlier than others (justified or not). Compare with two different 'cultures' in physics concerning QM: there is the camp of 'shut up and calculate', and look at what technology was developed on that basis! On the other side there is the camp that asks fundamental questions, e.g. the Bell theorem and experiments that are based on it. For the shut-up-and-calculators such experiments seem to be at most interesting, but of no use. But look what happened afterwards: from there we have now quantum cryptography, maybe one day we will have useful quantum computers.

So I would say: just give physicists time (pun intended).

2 hours ago, The victorious truther said:

Certainly some physicists do not. Such as Mach who tried to give an operationalist but failed abandonment of mass in classical physics by using the time integrated newtonian third law. Though, I find it rather strange we would shove such discussion far away from physics as in terms of certain theories (such as special relativity) its the pet philosophical interpretation popular with news organizations or well known physicists that got me interested in researching the philosophy here behind it. It's the philosophical interpretations that books, media, or even introductory material on the subject don't (pardon my language) shut up about that concerns me and yet were going to discuss it far away from physics?

Don't understand me wrong. The question 'what is time' is surely interesting, but for the biggest part, in 'daily physics', the question is not relevant. But it is a philosophical question through and through. So I am inclined to say that the relationship is the other way round. If somebody wants to philosophise about time, one better first gets an understanding about what physicists have to say about time, just to avoid that one is discussing time loose from any operational definition of time that has proven to be extremely useful.

[michel123456]

Time is a constituent element of Spacetime. The world we live in is (at least) 4D.

Geometrically, you can imagine a moving marble cube. It is a 4D object. If you take it to halt, it is still a 4D object because for some other observer it may be moving, and there is no preferred observer.

For the other observer it is a cube traveling in spacetime. For you it is a still standing cube: a cube at halt is "traveling in time".

An orthogonal projection of this cube on a surface reduces it as a 3D object (2D spatially+1D temporal)

An orthogonal projection of the surface makes it a line, which is a 2D object (1D spatially+1D temporal)

An orthogonal projection of the line makes it a point , which is a 1D object (zero spatially, 1D temporal)

And you just found what time is: it is a geometrical point that "travels in time".

It corresponds to the vertical line of a spacetime diagram.

Which seems maybe not very much helpful.

It only shows that in order to draw a point on a sheet of paper, you need time first. Without time you can't even think of standard geometry. The concept that we may have of a 3D space somehow "existing" independently of time is wrong.

You cannot construct some kind of 3D geometry and then add time in order to "turn the engine on" and create change. It is conceptually wrong. Time was there at the beginning prior to anything else.

Edited July 15, 2020 by michel123456

[swansont]

8 hours ago, The victorious truther said:

If it's possible to move this to that section please feel free to do so.

!

Moderator Note

Possible but not practical. As I said, if you want to discuss philosophy, open a thread in philosophy 

 

[Markus Hanke]

On 7/11/2020 at 10:57 PM, The victorious truther said:

Those who were proponents of material/physical change being above time/space (perhaps even making it non-existent or its structures mere abstractions) go under the label of spacetime relationism. Those who are proponents of the distinction of change to time or the existence of time without change  (check out the original Sydney Shoemaker thought experiment) went under the label of substantivalists.

How about if space and time are simply methods of the mind to structure information? Essentially, the mind takes certain raw data and uses this to continuously construct a model of reality, which we then become aware of as an object of consciousness. It is difficult to imagine what such a mental model could look like without some method to introduce spatial relationships and causal structure between its constituent parts. In that view, spacetime is quite real, just not necessarily as an attribute of the ‘world an sich’ (to paraphrase Kant, not that I necessarily agree with all his ideas), but rather as a function of the mind - which, interestingly, is itself part of the created model.

[michel123456]

On 7/16/2020 at 7:48 AM, Markus Hanke said:

How about if space and time are simply methods of the mind to structure information? Essentially, the mind takes certain raw data and uses this to continuously construct a model of reality, which we then become aware of as an object of consciousness. It is difficult to imagine what such a mental model could look like without some method to introduce spatial relationships and causal structure between its constituent parts. In that view, spacetime is quite real, just not necessarily as an attribute of the ‘world an sich’ (to paraphrase Kant, not that I necessarily agree with all his ideas), but rather as a function of the mind - which, interestingly, is itself part of the created model.

In this case, how do you explain space expansion & time dilation?