Does the Block Universe of Physics Mean Time is an Illusion?

[MacCrimmon]

Sunil, I am impressed. That reply seemed so complete to the point
It must be most of the answer in condensed form. I had trouble trying to copy it with the quotes to take time to study it or hang it on a wall. Better than a Picasso. And with the math too. It will take me some einfulung and time (pun intended) to understand it. It makes me feel like I'm trying to learn the violin on-line. I had to say this. If I am pointed on this it was worth it.

 

[PeterDonis]

The Schrödinger equation works fine in the relativistic field theory too.

If you pick a particular inertial frame, yes. But the time parameter in the equation is not "absolute time" as it is in the non-relativistic case.

This is essentially how realistic interpretations explain the violations of the Bell inequalities.

Discussion of this belongs in the quantum interpretations forum, not the relativity forum. It is off topic for this thread.

This is obviously not in contradiction with SR, but simply the Lorentz ether interpretation of SR which has a preferred frame.

This is also out of bounds for discussion here. Discussion of Schmelzer's theory, to the extent it is within bounds at all, belongs in the Beyond the Standard Model forum or the QM interpretations forum.

 

[PeterDonis]

That reply seemed so complete to the point

It is a reference to a particular proposed extension to current theories which is not mainstream. It is not a description of what mainstream relativity (or QM, but QM is off topic in this thread) says.

 

[bhobba]

I am referring to the use of an absolute time used by Schrödinger as being used in the manner of an inertial frame being the absolute beginning position.
But my comparison or conceptualisation of these two uses may be incorrect hence the question.

We now know Schrodinger's equation can be derived from the symmetries of an inertial frame and the Principle Of Relativity. See Chapter 3 Ballentine - Quantum Mechanics - A Modern Development. The time it uses is the time as I explained it in an inertial frame. No character is ascribed to it - it's simply a way of assigning a number to it - the shorthand of which is time in an inertial frame is what a clock measures.

This brings us to one of the key ideas of QM - what is the physical significance of Schrodinger's Equation. It is this - one uses Ehrenfest's Theorem to show it is exactly the same as the hamiltonian in classical physics. Such strongly suggests how to quantise a classical system - simply take the classical hamiltonian and replace the classical quantities with their quantum equivalents. Investigating this further however should be done over on the QM forum - not here. In the derivation of Schrodinger Equation in Ballintine, the Galilean Transformations are used, so when one takes the expectation values and notes it is the same as the hamiltonian in classical mechanics, it must be the hamiltonian in non-relativistic classical mechanics, because only in the non relativistic region are the galilean transformations valid:
http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/schr.html.

How to extend it to include relativity (ie the Lorentz Transformations) again should be discussed on the QM forum. For example one can make progress by assuming the same principle - using operators to replace quantities in relativistic hamiltonians.

Thanks
Bill

 

[PeterDonis]

We now know Schrodinger's equation can be derived from the symmetries of an inertial frame and the Principle Of Relativity.

Just to be clear, this is a Newtonian inertial frame and the Galilean principle of relativity, not the corresponding concepts in SR.

 

[Sunil]

How to extend it to include relativity (ie the Lorentz Transformations) again should be discussed on the QM forum.

But where to discuss the question if it is quantum theory which has to be extended, and not GR? Or how to extend SR/GR to make it compatible with quantum theory?

The name given for the not yet existing solution is "quantum gravity", suggesting a quantum theory, but no relation to GR. If there are problems of GR which prevent the use of standard quantum theory with the Schrödinger equation, and they can be solved in a modified interpretation of relativity (say, using the neo-Lorentzian interpretation of SR or the field theory version of GR or a neo-Lorentzian interpretation of it) to discuss it in the Special and General Relativity sounds appropriate. Not?

If you pick a particular inertial frame, yes. But the time parameter in the equation is not "absolute time" as it is in the non-relativistic case. Discussion of this belongs in the quantum interpretations forum, not the relativity forum. It is off topic for this thread.

How you name it is an interpretational issue. It fits into the definition of absolute time as given by Newton in this case too. Why would one discuss interpretational questions of SR/GR in the quantum interpretations forum (except if it is an aside from a question about quantum interpretations, given that some of them have to presume a preferred frame interpretation of SR/GR)?

This is also out of bounds for discussion here. Discussion of Schmelzer's theory, to the extent it is within bounds at all, belongs in the Beyond the Standard Model forum or the QM interpretations forum.

The discussion of the theory indeed. Simply mentioning it given that it is relevant for the issue discussed should be possible. The question I have answered was about the connection between absolute time and GR:

Could it be (and I am asking not speculating) that entangled particles seem to be influencing each other nonlocally because they are still sharing an absolute time reference. This would in no way be a contradiction or violation of GR or SR.

and to answer it it seems IMHO necessary (1) to point out that there is a conflict between absolute time and GR in the spacetime interpretation, and (2) that this is not a decisive argument against absolute time given that an alternative interpretation of the Einstein equations in harmonic gauge (as the limit of Schmelzer's theory) exists. Restricting the allowed answers here to (1) would obviously distort the answer against absolute time.

 

[PeterDonis]

where to discuss the question if it is quantum theory which has to be extended, and not GR? Or how to extend SR/GR to make it compatible with quantum theory?

Proposed extensions to current theories (GR and quantum field theory as it appears in the Standard Model), including proposed theories of quantum gravity, should be discussed in the Beyond the Standard Model forum.

 

[PeterDonis]

Why would one discuss interpretational questions of SR/GR

You have already been told, in another thread, that Lorentz Ether Theory, as an alternate interpretation of SR, is off limits for discussion at PF.

Theories such as Schmelzer's, considered as possible extensions of existing theories (i.e., possibly making different predictions in some domain), should be discussed in the Beyond the Standard Model forum.

 

[PeterDonis]

The name given for the not yet existing solution is "quantum gravity", suggesting a quantum theory, but no relation to GR.

Not at all. Most physicists who use the term "quantum gravity" mean finding a quantum theory that has classical GR as an approximation in some appropriate limit. Discussion of such proposed theories belongs in the Beyond the Standard Model forum.

 

[PeterDonis]

The question I have answered was about the connection between absolute time and GR

You didn't answer that question. You talked about how what you call "realistic" theories explain violations of the Bell inequalities. That has to do with quantum theory, not GR. This is the relativity forum, not the QM forum.

 

[MacCrimmon]

I am still learning how to speak "physics". But am learning fast.
Apparently this discussion may be addressed without QM or "proposed" theories.
In this way:
The name of this thread is "Does the Block Universe.of Physics Mean Time Is an Illusion?"
Since we are trying to approach this with a scientific mindset, we should accept (being rational not necessarily philosophical) that the answer we seek is an objective worldview synthesized from the sharing of experience hence the restriction to peer reviewed articles. This rule can be applied to answering the title of this thread because it implies a definition to "illusion". In this sense an idea may be an illusion if it has no evidence, it is self contradictory or is subjective without being objective. (as I interpret the Physics Forums rules.)
Since we agree by agreement to the rules to what illusion is, I ask about the Block Universe. Is it a model that for convenience removes seemingly nonessential factors including time? If so then time is not implied to be an illusion by Block Universe any more than ignoring factors such as energy in thought experiments of GR imply that energy is an illusion.
On the other hand if we are attempting to understand Block Universe as an objective reality then again it fails to present time as an illusion (that we have defined) since whether we view time as an absolute or relative, time remains a pragmatic consensus that we are relying on to share our experiences to form that scientific objective reality for peer review.

 

[PeterDonis]

Apparently this discussion may be addressed without QM or "proposed" theories.

In this forum, at least, yes, that's how it should be addressed.

I ask about the Block Universe. Is it a model that for convenience removes seemingly nonessential factors including time?

The Block Universe says that all of 4-d spacetime "exists" or "is real". Since "spacetime" includes "time", that would seem to indicate that the Block Universe does not "remove" time. However, all of these terms are vague so I'm not sure I mean by them the same thing that you mean by them. That's why physics uses math instead of vague ordinary language.

 

[MacCrimmon]

Thank you Peter.
The question is answered logically in that if we understand Block Universe as incorporating spacetime, and we accept Block Universe as not being self contradictory we must accept time as some objective reality.

 

[PeterDonis]

if we understand Block Universe as incorporating spacetime, and we accept Block Universe as not being self contradictory we must accept time as some objective reality

No, that's not what we must accept. All that we must accept is that the Block Universe not being self-contradictory means time might not be an illusion; we cannot say that the Block Universe not being self-contradictory requires time to be an illusion. But we also cannot say that the Block Universe not being self-contradictory requires time to not be an illusion, because the Block Universe might not be true; "not self-contradictory" is not the same as "true".

 

[MacCrimmon]

If we are using the math of Boolean 101 logic, then a self-contradiction cannot be true. If it is not true how may we make meaning from it? But if it contains no self-contradiction and employs an accepted more fundamental truth (time) in its construct then the more fundamental truth employed is also accepted. Then, it is accepted as not being illusion by the pragmatic purposes of peer review followed by the Forums.

 

[jbriggs444]

If it is not true how may we make meaning from it?

You may want to step over to the mathematics forum to debate this. Good work has been done in mathematics to establish a reasonable and useful definition for "true" that is independent of physical reality.

In mathematics, for instance, we have the Euclidean and non-Euclidean geometries. In Euclidean geometry we have the parallel postulate. In non-Euclidean geometries that postulate cab be falsified. Yet we can prove that if Euclidean geometry is consistent then so is non-Euclidean geometry.

We can prove theorems and do geometry either way.

Which is "true"? It depends on the model. There are useful models where Euclidean geometry is "true". There are useful models where non-Euclidean geometry is "true".

Similar for the continuum hypothesis and the axiom of choice. We can take them or leave them.

 

[MacCrimmon]

Any system of math using a set of postulates may express a contradiction to another system of math using a different set of postulates. (or may not) but any system of math used may not be valid if it contradicts its own postulates.
The math topic was introduced by the mentor.

 

[PeterDonis]

if it contains no self-contradiction and employs an accepted more fundamental truth (time) in its construct then the more fundamental truth employed is also accepted.

You are saying that, because time is "an accepted more fundamental truth", then it cannot be an illusion. But this argument (a) has nothing whatever to do with the Block Universe, and (b) is circular, since you are basically assuming your conclusion ("accepted more fundamental truth" is basically equivalent to "is not an illusion").

 

[jbriggs444]

Any system of math using a set of postulates may express a contradiction to another system of math using a different set of postulates.

Yes. I thought I'd just given an example of such.

(or may not) but any system of math used may not be valid if it contradicts its own postulates.

If you can prove a contradiction, you have an inconsistent system. That's a bit stronger than "may not be valid".

None of this has anything to do with "illusion", whatever that means.

 

[MacCrimmon]

Thank you Peter. I think your correction of my phrase "more fundamental truth" is justified. And from that point it is also becomes a circular argument. Is it better if I say simply that Block Universe employs some concept of time in its construct as you asserted it uses the concept of spacetime?

 

[PeterDonis]

Is it better if I say simply that Block Universe employs some concept of time in its construct as you asserted it uses the concept of spacetime?

That would be fine, yes.

 

[Sunil]

Not at all. Most physicists who use the term "quantum gravity" mean finding a quantum theory that has classical GR as an approximation in some appropriate limit. Discussion of such proposed theories belongs in the Beyond the Standard Model forum.

Ok, I have started a discussion at https://www.physicsforums.com/threads/will-qg-leave-gr-unchanged-or-qt.996228/

You have already been told, in another thread, that Lorentz Ether Theory, as an alternate interpretation of SR, is off limits for discussion at PF.

Theories such as Schmelzer's, considered as possible extensions of existing theories (i.e., possibly making different predictions in some domain), should be discussed in the Beyond the Standard Model forum.

Correct, but my question was not about discussing them, but simply referencing them if this is necessary to support simple existence claims with a reference to scientific literature. (I have no problem to add myself a remark where those referenced theories resp. quantum interpretations have to be discussed.

But not referencing papers which are relevant for the question discussed is a reason, say, for referees to ask for modifications of papers. Today in "publish or perish" physics it is quite common that the authors simply don't know all the relevant literature, so it is also common that they are asked to add some references. This does not mean that one is obliged to discuss them, one can simply write "we will not discuss here [...]", but a reference has to be given if it is relevant.

And even if postings in a forum are something quite different, I think that what would be obligatory in a scientific article should not be forbidden in a scientific forum. To give correct information about the alternatives is, last but not least, even a moral obligation.

You didn't answer that question.

I disagree, but I think this is a minor quibble not worth further consideration in detail.

You talked about how what you call "realistic" theories explain violations of the Bell inequalities. That has to do with quantum theory, not GR. This is the relativity forum, not the QM forum.

Given that realistic interpretations require absolute time, but other interpretations don't, I think it is obligatory to refer to them (but not to discuss them) if absolute time is considered.