michel123456

23 hours ago, vexspits said:

I think it might be more a matter of some “idea of time” being inside your thinking.

Which is perhaps why you add, “at the same time” to “all the parts are present together” which to me adds nothing. 

Just for the hell of it, as an experiment, you might try throwing the word “time” out the window (and all its accompanying baggage), and focus on relationships that persist (such as distances between positions on a cup) and the inherent structure as a whole that arises out of those persisting relationships. Instead of thinking “the inherent structure exists at a time” just think: “the inherent structure exists”. Or “it persists”, not “it persists through time”. 

Now if you cry fowl here and say, “The only way the structure can persist is through time”, I submit to you that you’re adding something vague and extraneous in the sense that it doesn’t contradict the notion of change as presented by Marcus. We have to be clear that we are talking about a parameter, not some other notion of time which you or I might espouse.

PS. Although I have to admit, I’m very curious as to how you would define “time” outside the time of physics. Maybe a new thread in the philosophy sub forum. 
 

 

Foul.

To me (but that might be only me) in order for something to be, time must be there. Either time arises from the existence, or time is a necessity prior to existence, I don't know. But you cannot "be" out of time. You cannot "persist" in something that you want to cancel. It is a wrong concept. IMHO.

To be more pragmatic and step out of pure philosophy, I have the feeling that in the frame of GR it should be possible to show that Time & Space are inseparable. That one cannot establish the concept of Space without Time. That the concept of 3D space "existing" or "persisting" without the concept of time intertwined  to it does not represent anything close to anything.

1 hour ago, Markus Hanke said:

There is of course no observer in such a universe, since no act of observation is possible - but does that imply that the tea cup cannot exist? Does existence (in the ontological sense) require a temporal dimension? I think not.

Interesting how we disagree. Please explain your concept.

22 hours ago, studiot said:

 

You have missed the crux of my discussion with Marcus and Michel about the teacup.

 

 

 

 

 

I understand what you mean.

Yes, your tea cup has different curves, and it happened that I didn't know why I should argue against your argument. It makes sense. The curve changes in relation with the spatial coordinates. No time involved.That seems OK

But after more thinking when you are stating "when all the parts are present together", I suspect that you mean "all the parts are present together at the same time". Or maybe (I don't know to say otherwise) that your cup somehow is existing there in space "out of time". As if the concept of a cup "existing" could be understood without the concept o time. But the concept of "together" has already the idea of time inside it. When the bus hits you, it is because you shared the same space together at the same time.

Because together at different times makes no sense. If you share the same space at different times, you are not "together".

And after more profound thinking, in your statement, there is time 4 times: when all the parts are present together

_when

-are

_present

-together

20 hours ago, studiot said:

Good examples of other running variables are temperature and composition.

Good point.

Maybe inside the concept "variable" there is also time hidden.

Test walking

18 hours ago, joigus said:

Do you know I have this same gut feeling? I would love to discuss this point, whenever you have the time.  +1

I'm currently involved in a discussion with a mathematician friend of mine who says it doesn't. I, on the contrary, always have the feeling that in mathematics there's always a sequence of operations, if nothing else, which foreshadows time. Doesn't it?

He says no, and I'm not convinced.

Edit: That not to mention the concept of probability on a purely mathematical basis, which I think is heavily impregnated with a notion of time by construction.

You're welcome.

I have to admit that I am quite surprised because the last time I suggested that time could  inherently be inside mathematics I was hit by Zeus thunderbolt.

14 hours ago, studiot said:

Let us return to Marcus' cup for a moment. ()

Now for there to be a cup, all the parts (handle, bowl, base etc) all have to happen all at once.

It is the archetypal 'block universe' where all parts of the universe happen or exist, even when the 'focus' is not upon them.

So the 'change' can be thought of as a comparison of the properties (eg curvature) from once place to another.

So we can compare the curvature of the handle to that of the bowl and draw the conclusion that it must exceed the curvature of the bowl since it goes round the outside of the bowl.

Time is not needed or involved in this comparison.

 

IMHO what is described as a "change" is in fact a "difference".

Another example: you walk in the desert an then enter the savanna, then the jungle. You can eventually say that the land changes (like the cup curvature) but what you are describing is not a "change in the environment", what you are describing is yourself traveling.

I my mind for change to appear you need a before/after relation.

In the spatial tea cup example,  how do you change spatial coordinates? Or how do you hover over the cup in order to notice the curve change?

On 7/22/2020 at 11:22 AM, Markus Hanke said:

You got it
That being said, our hypothetical tea cup system here is a stationary system, since nothing else is possible in a 3D universe. Meaning, if the cup is empty, it cannot ever be filled, since that would necessarily require a change with respect to some coordinate other than a spatial one. This would be a pretty boring universe  

You can even say that the cup cannot have been created, it was always there. It is a mathematical cup-universe in which nothing can happen.

I have even the gut feeling that mathematics have inherently time inside it. How can you make any calculation without time?

2 hours ago, Markus Hanke said:

so you can have time without any process of change happening

But can you have change without time?

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?

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.

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?

So that puts us back to square zero.

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"?

And here another star vanished: (the headline of the article is funnily close to the title of this thread)

https://astronomynow.com/2020/07/02/now-you-see-it-now-you-dont-a-massive-star-disappears/

That is out of my knowledge. The only thing I can say is that trying to change the elements (river, sea, land) in a specific way most of the times drive to unexpected results. I have the experience where a hotel constructed a small dock in the sea for his single inflated boat sportcraft had the result to erase completely its sandy beach.

19 hours ago, Ken123456 said:

Anyone interested?

Maybe, but as stated above your pictures are not showing.

Ans some more explanation maybe?

What do you mean with "wash away"? transformed in open sea, or transformed in agriculture? or what else?

10 minutes ago, swansont said:

You must have a problem with archaeology and paleontology then, too. Some natural event wipes out evidence, and now we have no clue about some bit of history. 

There is no cosmological principle in archaeology, AFAIK

25 minutes ago, swansont said:

No, they will not infer different physics, if you mean that the physics will be contradictory. They may not have enough data to construct some physics (should knowledge be lost), but the physics they have will be the same.

There again, according to your reasoning, we must consider ourselves as the lucky ones that have access to all the information while the other observers in the far future will not have that chance.

Doesn't that ring a bell to you? Do you accept that idea without an inch of scepticism?

1 hour ago, pzkpfw said:

Because the Universe is changing and they are observing at different times, yes, that's possible.

Will you answer my questions?

1. Do you think an observer of the Universe 1 hour after the BB would see the same thing we do now?

2. In your scenario, how would the hypothetical me be asking the other about the BB? Where did I get information from that he didn't have?

1. No, he will not see the same thing as we do now. But he would know about the BB. So no problem to me.

2. Good question: he would live in a universe without the BB.  He would not get any information about the BB. He may suspect that his galaxy has been created woof just like that by some kind of magic, or that his galaxy was always there & will remain forever. Anyway he would have no clue about the BB & thus should base his physics on some other Theory. So that is a problem to me.

2 minutes ago, swansont said:

No, they will not infer different physics.

Please explain.

They will live in a world without CMB

8 hours ago, pzkpfw said:

NB: that observers in the future might observe a "different" Universe than observers today, is not a violation of the cosmological principle.

Even if these observers infer different physics?

1 hour ago, zapatos said:

How is that not fair? It will look exactly the same to observers from any of those other billions of galaxies as it looks to us.

That means it will be unfair for everybody.

Just now, swansont said:

Strange already asked you not to steer this thread in that direction. I agree with that request.

But that is related. If you believe in Universal Now or not. One must be consistent: if you are refuting Universal Now you cannot invoke it for another explanation. You cannot cherry picking explanations that contradict the other in order to explain the universe.

And i am glad that you feel uncomfortable about it.

24 minutes ago, swansont said:

As an analogy, a set of twins will look the same. But compared to each other, at the same age, not comparing different ages.

Oh. Does that mean that the entire Universe is now?

32 minutes ago, pzkpfw said:

Nope, I'm saying that because the universe is changing the Universe will look different at different times.

Your quote from wiki that you based the above on was: "the universe looks the same whoever and wherever you are" ... note that that does not say "whenever".

 

Question: do you accept the "big bang theory"?

Follow-up: do you think an observer of the Universe 1 hour after the BB would see the same thing we do now?

Indeed the whenever has been introduced by me.

It does not bother me that the universe is changing, expanding, faster. it bothers me when the Theory predicts a silly situation where the universe becomes incomprehensible. Imagine yourself as an observer in this future krauss galaxy. You are observing the sky and no trace of the BB. You are discussing with another guy and ask him if accepts the BB Theory. The other guy answers: What are you talking about? (He knows nothing about the BB Theory because he is observing a single Galaxy inside a huge void.) Isn't that complete bogus? Similarly, if this situation is possible, why would I accept that the universe is playing fair with me today? Why would I accept the cosmological principle today if it does not count tomorrow?

6 minutes ago, zapatos said:

No, I do not disagree with the cosmological principle. It does however appear that you don't understand the cosmological principle. The cosmological principle does not state that everyone will see the same thing at all times. Which should be obvious to anyone who recognizes that things change over time.

Read again the cosmological principle: from wiki

Quote

The cosmological principle is usually stated formally as 'Viewed on a sufficiently large scale, the properties of the universe are the same for all observers.' This amounts to the strongly philosophical statement that the part of the universe which we can see is a fair sample, and that the same physical laws apply throughout. In essence, this in a sense says that the universe is knowable and is playing fair with scientists.^[1]

The "is playing fair with scientists" part is the reason of the title of this thread.

Following Krauss argument, in accordance to todays paradigm, in the future the universe will not "play fair". It will show a single galaxy in a huge void with no evidence at all for the existence of billion galaxies or the BB. Something does not sound good here.

If the part of the universe which we can see is a fair sample, then the dinosaurs should have taken the same conclusion. And a future astronomer will make the same strong philosophical statement. If our model of the universe does not allow to some observer to make this statement, then most probably our model is wrong.

34 minutes ago, swansont said:

Can you point to the evidence that this “central position in time” is the paradigm?

Well, the paradigm states that we are not close to the beginning: the BB supposedly happened 13,8 BY ago.

And as far as I know, not any one of existing Theories about the fate of the universe states that the time Now is close to its end.

On 6/22/2020 at 5:46 PM, zapatos said:

They are NOT the exact same things.

You are confusing the word "special" with the word "preferred".

We don't laugh at the the idea of the Earth being in a special place, we laugh at the idea that the Earth might be in a preferred place.

When you were but a wee child and your mother said you were "her special boy", she simply meant you held some significance for her. You were 'neat', or 'cool'. She wasn't implying that the universe was centered on you.

Similarly, we live in a special time and place. We witnessed the first time humans detected gravity waves and the invention of the autostereogram. If we weren't at this location (on Earth) at this time, we could not have seen that with our own eyes. Unfortunately we did not exist at that special time when the four fundamental forces were combined, but we are lucky to live at the special time when all these superclusters can be detected. And that is really neat.

 

In this case you must disagree with the cosmological principle. The dinosaurs were living on the other side of the galaxy, in another location & another time & thus witnessed a different universe because the universe is changing.

The only one who is observing the same universe than we do is some E.T. on another planet somewhere else in the universe, right Now. But Universal Now does not exist. Or am I wrong?

2 hours ago, joigus said:

+1.

I think I speak for most everybody here (although I cannot be sure) if I say that there seems to be a kernel of anthropocentrism in your argument. Am I right?

That's what's making me uncomfortable, anyway. Please, correct me if I'm wrong.

Against anthropocentrism.

The current paradigm is that we the humans are the lucky ones in the middle of the time line of the universe. To me it is highly unlikely.

We know that we are not in the center of the Universe: our position is totally random. We are "lost in space". But we (you) believe that we are in a central position in time. I disagree. My opinion is that we  should consider space & time in exactly the same way: we are lost in space & we are lost in time. Our observation of the universe has nothing special, it is a representative image of the universe and almost identical for any observer in space & in time.

That shouldn't be so difficult to accept, it is simply a slightest extension of the cosmological principle.

I understand that it may be difficult to swallow, since it goes against the "life of the Universe" accepted Theory. But when a Theory gives you the result that in a few billion years, the future scientists will live in a middle age universe made up of one single galaxy inside a huge void, I think that the least one should do is to raise some doubt.

21 minutes ago, joigus said:

Please, stay away of ad hominem.

OK. I am sorry. And I was wrong: I have no doubt about his intellectual abilities.

55 minutes ago, Strange said:

And we see that they were different in the past. (Ultimately, we see all the way back to when the universe was uniformly full of hot plasma)

No it doesn’t. It is only talking about locations in space. (Please don’t turn this into yet another thread on your inability to understand the finite speed of light)

I am starting to wonder about your intellectual abilities.

8 hours ago, pzkpfw said:

Pick a random spot on Earth. Maybe you pick a desert. Or a mountain top. Or the arctic. Or a rain forest.

A single random choice does not have to match any other.

 

The Universe is changing. The particular time we happen to be observing it - we simply see what we see.

Your idea that "all random points should observe roughly the same thing" relies on the Universe being static and unchanging.

But then, if you are correct, it goes again the cosmological principle.

From Wiki https://en.wikipedia.org/wiki/Cosmological_principle

Quote

The cosmological principle is usually stated formally as 'Viewed on a sufficiently large scale, the properties of the universe are the same for all observers.' This amounts to the strongly philosophical statement that the part of the universe which we can see is a fair sample, and that the same physical laws apply throughout. In essence, this in a sense says that the universe is knowable and is playing fair with scientists.

What means "fair sample" in the above statement, when you seem to be confident that nature does not play "fair"?

Do not forget that a difference in space means a difference in time. Objects that we are currently observing in the sky are in a different time than we are. The far away ones are in a long past.

The cosmological principle depends on a definition of "observer," and contains an implicit qualification and two testable consequences.

From wiki again

Quote

"Observers" means any observer at any location in the universe, not simply any human observer at any location on Earth: as Andrew Liddle puts it, "the cosmological principle [means that] the universe looks the same whoever and wherever you are.

At any location in the universe means also "spread over time", because each location is at a different time.

What you seem to say is that "the universe looks DIFFERENT whoever and wherever you are because the universe is CHANGING" (sorry for putting words in your mouth).