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The electron is a theory we use; it is so useful in understanding the way nature works that we can almost call it real.

Great quote by Feynman

Now is real but i don't think then is and here is real, but again i don't think there is. i experience here and now exclusively is this not real enough?

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relativity  Compartment 1 What do you mean no one said that ? Do you and I exist at the same time, NOW? Spacetime SAYS THAT we do. Compartment 2 Relativity, which you keep asking

of course  Relativity is not wrong, it says now is relative which is the point- now at different times- means the spacetime model is wrong, it is just a time model. The different times now exis

Clever compartmentalization, but there is no time flow in realtime it is always now, so you are nullifying realtime by saying in the context of spacetime, same dumb argument every time. In the c

2 hours ago, pavelcherepan said:

As MigL has correctly pointed, there is another way of looking at it. Is it likely that our understanding of space-time or electric fields will change significantly in time?

Since electromagnetism or GR are both theories, we are meant to update and change those if conflicting evidence shows up. Therefore, our understanding of what those phenomena are can, and most likely will change over time. New theories based on new observations can show it in completely different light. At the same time observable effects of space and time or electric fields, or electrons, will still stay the same. Therefore, I would consider those as 'real', but any theory or model can only be 'real' at one particular point in time.

I'd rather say our resolution of what any particle really is improves with the development of our theories. After all, any better theory won't simply replace but rather incorporate what we already know. After all it has to account for the observations we've already made

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45 minutes ago, YaDinghus said:

After all it has to account for the observations we've already made

Of course but space in classical mechanics and GR are radically different even though GR accounts for same observations plus some on top.

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12 hours ago, beecee said:

Throwing in my $2 worth, if a model is successful and widely used, I believe it can logically be referred to as real.  Newton told us that gravity is the attraction between masses, but that he did not have any clue why. Einstein came along and informed us that the background metric against which we locate events and call spacetime is curved and warped in the presence of mass, and this curvature is why masses attract and which we call gravity.

Classical E&M says EM radiation is a wave. QM says it's a photon. Both are successful and widely used.

Similarly for sound. Are phonons real? Is vibration actually a particle?

 

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19 hours ago, argo said:

The electron is a theory we use; it is so useful in understanding the way nature works that we can almost call it real.

Great quote by Feynman

Now is real but i don't think then is and here is real, but again i don't think there is. i experience here and now exclusively is this not real enough?

Better punctuation - Now is real but i don't think then is. Here is real, but again i don't think there is. i experience here and now exclusively, is this not real enough?

Point B- there and then- is the abstraction, this point is not real but it is so useful to say it does when it comes to measuring time and distance we can almost call it real, the only point that does exist is the one we experience, point A- here and now. SR is key to understanding that all point have the point A perspective here and now,  the point B perspective -there and then- is what another point has of you.

You don't need a point B to be able to measure space and time it is just more convenient than having only point A's. Point A is a moment in time therefore at different times there can be different points. Check this against QM and SR if you like.

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Soooooo...

Reality is subjective ?
Everyone experiences a different reality ?
There is no reality unless someone is there to experience it ?

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4 hours ago, MigL said:

Soooooo...

Reality is subjective ?
Everyone experiences a different reality ?
There is no reality unless someone is there to experience it ?

I half addressed that earlier to say that I didn't think this  but gave no reason... apart from bias.

https://www.scienceforums.net/topic/115336-time-and-space/?do=findComment&comment=1061119

 

Perhaps it might be the case that  a reality can be understood as both subjective and objective. The world does indeed continue indifferent to our observing  it  but is a different place for our doing so (observing it) .

 

We do all observe a different reality  but  we also share (and are a facet of) the same objective reality without a contradiction. 

 

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20 hours ago, MigL said:

Soooooo...

Reality is subjective ?
Everyone experiences a different reality ?
There is no reality unless someone is there to experience it ?

no, no and no

didn't say this at all

whats real and whats not was the subject i was tying to add to.

Every point in the universe must exist here and now, dismiss it if you want.

You exist here and now, a rock exists here and now, empty space exists here and now, i didn't mean to imply here and now needs to be experienced.

If you pick any random point in the universe and call it point A and it exists here and now, then you must have a better explanation than it exists at a different time to all the other points that also exist here and now, soooooo what is it?

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I disagree, let’s have a look and see if relativity does allow now to be defined, again just because the spacetime model is very useful does not automatically mean it’s true.

Imagine now is granular, not universal and here emerges at each point as a necessity to exist. Two points that are the same cannot exist at the same time so in this model every point exists at a different time.

Generally speaking then all points would actually be the original point, not only does relativity allow for this it could be said this is the cause of relativity.

SR

As an accelerated point speeds up toward itself at the next time it would get closer reducing the length of the line therefore accounting for length contraction, time dilation and an eventual speed limit. The relative space between points is actually smaller not just shorter so all values of that space such as mass and energy must also be actually smaller accounting for mass-energy equivalence. The relativistic mass is observed/measured from the accelerated point’s perspective where it is the stationary object and everything else is accelerating hence the universe gets smaller or vice-versa the relativistic mass of the point increases and finally as there is only one point that exists at a time there can be no such thing as simultaneity.

QM

Here and now is a point but because this is purely a time model and not a spacetime model here and now is also a wave.

Conclusion

Spacetime has a flow of time from past to future but in this purely time based model it is always now and what clocks measure would be the movement between individual points only.

Your not wrong, you cannot define a universal now but perhaps now isn't universal, just a thought.

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58 minutes ago, argo said:

Two points that are the same cannot exist at the same time

Why not? 

58 minutes ago, argo said:

Generally speaking then all points would actually be the original point, not only does relativity allow for this it could be said this is the cause of relativity.

Can you

(a) show mathematically how relativity allows for this

and

(b) derive relativity from this (in mathematical detail)

58 minutes ago, argo said:

As an accelerated point speeds up toward itself

How can something move towards itself?

58 minutes ago, argo said:

The relative space between points is actually smaller not just shorter so all values of that space such as mass and energy must also be actually smaller accounting for mass-energy equivalence.

I don’t see how this explains mass-energy equivalence. Please show the mathematics. 

58 minutes ago, argo said:

finally as there is only one point that exists at a time there can be no such thing as simultaneity.

Simultaneity is relative, not nonexistent. 

But if there is no such thing as simultaneity, then there is no universal now. Which is what you disagreed with initially. 

58 minutes ago, argo said:

Here and now is a point but because this is purely a time model and not a spacetime model here and now is also a wave.

Another assertion with no theoretical basis or evidence. 

Edited by Strange
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12 hours ago, Strange said:

Why not? 

because they are the same point, can you exist in two places at once? No but you can exist in two places at different times.

 

12 hours ago, Strange said:

Can you

(a) show mathematically how relativity allows for this

and

(b) derive relativity from this (in mathematical detail)

No but i have explained the idea, you have to start somewhere, right? Better to see if an idea is worth the trouble first and nonsense is always easy to shoot down, go ahead make my day.

12 hours ago, Strange said:

How can something move towards itself?

Time based model, one point at different times

12 hours ago, Strange said:

I don’t see how this explains mass-energy equivalence. Please show the mathematics. 

100% of the universe = 100% of the mass and energy, 1/2 the universe and you half the mass and energy. The math is not difficult here.

12 hours ago, Strange said:

Simultaneity is relative, not nonexistent. 

But if there is no such thing as simultaneity, then there is no universal now. Which is what you disagreed with initially. 

Another assertion with no theoretical basis or evidence. 

Every point exists at a unique time, every point is relative to the time it exists in. No two points exist at the same time simultaneously in this model, yes simultaneity is relative but to time.

Its a time model, now is not universal i.e. time is not an overlaying dimension it is a timewave of the original point. i thought i was disagreeing that relativity ONLY allowed a universal  now.

You give no reason why this is not a viable alternative and seem unable to grasp the basic idea, probably in part how i explain things, i will try to be more careful. 

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2 hours ago, argo said:

because they are the same point, can you exist in two places at once? No but you can exist in two places at different times.

But that is not what you said.

2 hours ago, argo said:

Time based model, one point at different times

A single point can move away from where it is, or it can move towards something else. It can't move towards itself; it is already there

2 hours ago, argo said:

100% of the universe = 100% of the mass and energy, 1/2 the universe and you half the mass and energy. The math is not difficult here.

I assumed by "mass-energy equivalence", you were referring to the equation e=mc2 and that mass can be converted to energy. Just saying that the whole universe contains all the mass-energy in the universe (which is trivially true, even if the universe is infinite) doesn't really explain anything.

2 hours ago, argo said:

Every point exists at a unique time, every point is relative to the time it exists in.

So by "point" do you mean the same as what is called an "event" in relativity (ie. a set of x,y,z,t coordinates)?

2 hours ago, argo said:

No two points exist at the same time simultaneously in this model

I don't see why not. And it would seem to limit the usefulness of the model because it implies nothing can ever interact with anything else (because they can never be at the same place and time).

2 hours ago, argo said:

i thought i was disagreeing that relativity ONLY allowed a universal  now.

There is no universal "now" in relativity. Time is relative to the observer. The time between events, and even the ordering of events, depends on who measures it.

2 hours ago, argo said:

You give no reason why this is not a viable alternative and seem unable to grasp the basic idea, probably in part how i explain things, i will try to be more careful

It is very vague and not very useful until you can show that it produces practically useful results (ie the same results as relativity).

Edited by Strange
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On 21/7/2018 at 3:59 AM, MigL said:

Reality is subjective ?

Yes of course.

On 21/7/2018 at 3:59 AM, MigL said:

Everyone experiences a different reality ?

Obviously. 

On 21/7/2018 at 3:59 AM, MigL said:

There is no reality unless someone is there to experience it ?

I think that question is ill posed, since the very notion of “reality” is inherently dualistic, and thus dependent on the observer. If you remove all observers, the question no longer makes any sense. I think it is rather more interesting to turn things around - given a particular observer with particular physical and mental structures, what kinds of realities can be experienced? 

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1 hour ago, Markus Hanke said:

 

I think that question is ill posed, since the very notion of “reality” is inherently dualistic, and thus dependent on the observer. If you remove all observers, the question no longer makes any sense. I think it is rather more interesting to turn things around - given a particular observer with particular physical and mental structures, what kinds of realities can be experienced? 

 Are the observer and the observed  two facets of a same dynamic continuum?

 

Does the observed change the observer and the observer change the observed?

 

As someone (Ophiolite ) said we are the universe looking at itself (philosophy or physics?)

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2 hours ago, geordief said:

Are the observer and the observed  two facets of a same dynamic continuum?

There are probably many different philosophical stances towards this, so this is just my own opinion. I think the answer is yes, they are both part of the same “continuum” (if you so will), and “reality” is given by the relationship between subject and object. There is then again the question of how fundamental that duality actually is. But this is not a discussion that belongs on this thread.

2 hours ago, geordief said:

Does the observed change the observer and the observer change the observed?

That’s a good question. It’s a definite yes to the first part, but I’m not so sure how to answer about the second. I would tentatively say “yes” to the latter also, since we don’t experience raw sense data, but rather our mind’s interpretation of it. In that sense, we do perceptually “alter” the observed in quite radical ways. 

3 hours ago, geordief said:

As someone (Ophiolite ) said we are the universe looking at itself (philosophy or physics?)

We are a physical system subject to all the usual laws of physics, so this is manifestly (and trivially) true, so long as you don’t add other elements that are not part of physics, such as a soul, or some kind of non-physical form of consciousness that is separate from the physical body. So this issue is somewhere on the interface of physics, philosophy, and spirituality.

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More philosophy than physics, but from a practical point of view, we can never know reality other than through our interactions with it ( as Swansont has noted ).
These interactions both limit our understanding of 'reality', and, yes Geordy, affect our reality.
All we have are mathematical descriptions of 'reality' modelled on the observed interactions, and so our perceived reality changes with our models.

For us, 'reality' is the model, and so is subjective, Markus.
But reality would still be there without a model/interaction/observer.

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35 minutes ago, MigL said:

More philosophy than physics, but from a practical point of view, we can never know reality other than through our interactions with it ( as Swansont has noted ).
These interactions both limit our understanding of 'reality', and, yes Geordy, affect our reality.
All we have are mathematical descriptions of 'reality' modelled on the observed interactions, and so our perceived reality changes with our models.

For us, 'reality' is the model, and so is subjective, Markus.
But reality would still be there without a model/interaction/observer.

Thinking about this: 'reality' can only ever be how things interact with other things. As a macro-analogy: how you interact with me will be different to how you interact with somebody else. Which interaction of the two reveals your true nature?

Edited by StringJunky
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Relativity of simultaneity is the relativity of a now that exists at different times, how else could you possibility be imaging it?

If you were to say, “from the perspective of…” then you are talking about the perception of now. A comparison between perspectives is a comparison between two different times when now exists.

Now on a platform can be shown to be different from now on a train but by some compartmentalization of the mind this doesn’t equate to there being more than one now?

I don’t understand, how can anybody say there is only one universal now if there is more than one perspective?

compartment 1

spacetime with one universal now is seen to be the basis for relativity 

On 7/22/2018 at 1:25 PM, MigL said:

You may be able to define 'here'; but you cannot define a universal 'now'.
relativity doesn't allow for that.

compartment 2

There is no universal "now" in relativity.

On 7/23/2018 at 9:16 AM, Strange said:

There is no universal "now" in relativity. Time is relative to the observer. The time between events, and even the ordering of events, depends on who measures it.

Am i missing something? If simultaneity of relativity is based purely on time then what i am saying produces the exact same results as relativity.

Edited by argo
QUOTE was in wrong compartment
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On 23/7/2018 at 6:14 PM, MigL said:

For us, 'reality' is the model, and so is subjective, Markus.
But reality would still be there without a model/interaction/observer.

I think that very much depends on how you define “reality”. If you take it to be a subjective model, as you state above, then it is necessarily dependent on the presence of a subject who experiences and creates it. Without such a subject, the notion no longer makes any sense.

I am not trying to claim that nothing exists without an observer, it’s just that we might perhaps need to broaden our understanding of what “reality” really means. To bring this back a bit more towards physics, refer to the concept of counterfactual definiteness in quantum physics.

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8 hours ago, argo said:

Am i missing something? If simultaneity of relativity is based purely on time then what i am saying produces the exact same results as relativity.

Relativity of simultaneity depends on relative velocity. 

You can claim your idea gives the same results as relativity but you need to prove that mathematically. And if it does, then what is the point ?

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From your last post, Argo, you seem to have the impression that my quote ( compartment 1 ) justifies a common universal now.
If you re-read it, I'm sure you'll realize I stated the exact opposite.
Relativity DOES NOT allow for a universal now

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On 7/22/2018 at 1:25 PM, MigL said:

You may be able to define 'here'; but you cannot define a universal 'now'.
relativity doesn't allow for that.

9 hours ago, MigL said:

From your last post, Argo, you seem to have the impression that my quote ( compartment 1 ) justifies a common universal now.
If you re-read it, I'm sure you'll realize I stated the exact opposite.
Relativity DOES NOT allow for a universal now

hummm

First

You're saying i cannot define now like the many points that are here and here and here....i.e..there is only one universal spacetime now. 

then

You're saying relativity DOES NOT allow for a universal now...every now is relative...i.e. there are many relative nows.

 

compartment 1

Spacetime - many here, one now

compartment 2

Spacetime- many here, many now

I cant make a constructive argument with compartmentalized minds that allow a switch of stance whenever it suits.

Strange

The point is that relativity insists on many points that are now, spacetime on the other hand DOES NOT, it insists on one now.

The evidence for relativity must outweigh the idea of spacetime and no matter how useful spacetime may be it is only a speculation.

Spacetime belongs in the trash but instead the whistle blower is.

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