The reality of time, Lee Smolin lecture.

[vlaiv]

23 minutes ago, andrew s said:

I have been trying to understand time since the 1970s. I have read numerous books taking a philosophical, scientific and biological approaches and am yet to find consensus across them.

In modern physical theory time is a parameter on a continuous curve defined on the space-time manifold. In QM and SR this is flat Minkowski space-time and in GR curved Riemannian/Einsteinian space-time which in small enough regions conforms to flat space-time. " Now for an event" is well defined as the point at which the event occurs (space and time) as viewed in a particular co-ordinate system. What is invariant between frames it that they agree on the past and future light cones of the event.

The idea of time came about as we observed things changed and our own perceptions of that change. Our physiological sense of time and now is just that and is far removed from the abstraction of time and now in the description I gave above. I doubt we will be able to reconcile them here as they are fundamentally different perspectives. They are the same words having very different meaning in the two contexts - not uncommon with technical language v everyday usage.

Regards Andrew

I believe this is the key for whole discussion. "Now for an event" - can coincide with perceived now, but also be located in past or in future. So "Now for an event" is not correct "now" in this context.

Whole point of the presentation was, as far as I understand it, to include perceived now as real physical phenomena, not just psychological phenomena and see what it can contribute to theory. But in order to do so, we need a good definition what "real now" is - and it is not point in space-time.

I don't think it is the the case - we perceive it, therefore it must be true, but rather - it is true and this is why we perceive it in the first place. But in order to devise either true experiment or thought experiment that will either support or disprove this, we really should understand what is it that we are trying to work with - so we do need better definition of phenomena rather than - it is psychological, or perception.

[Rodd]

1 hour ago, vlaiv said:

Saying that without game there would be no change is equivalent to saying without life in environment there would be no change of birds - quite true, but still does not imply that there is third party involvement in either.

No, what I said was your game insists that every action results in either something good or bad (defined by the parameters of the game).  This is not so, as you know.  Most mutations are neutral--neither good nor bad.  

Back to time.     When the universe was expanding, expansion did not move through the universe, expansion happened at every point simultaneously (not counting on small irregularities that may have existed).  Now pertains to everywhere.  the clock is a good example...12:00 here is 5:00 in Australia.  So we can't use the clock--but now can happen at both places--just entangle two particles and send one to Australia.   How to define "now"?  I will leave that to those of you who can write equations!

Rodd

[vlaiv]

5 minutes ago, Rodd said:

No, what I said was your game insists that every action results in either something good or bad (defined by the parameters of the game).  This is not so, as you know.  Most mutations are neutral--neither good nor bad.

Not sure that I ever mentioned good or bad, and these labels are context sensitive - I just mentioned fitness function, without prejudice. Fitness function is case of particular game mentioned randomly chooses which chains are removed and which ones are "kept in the game". For particular fitness function - remove shorter chains with higher probability, result of evolution is that most of population is longer chains. I know that this looks kind of straight forward, but if we want more complexity we can define fitness function to include color of paper clips for example.

Try thinking in abstractions. We have one example of evolution that is ever present around us - biological evolution on earth. But that does not mean that it is only evolution based on these premises that we have identified. Think of it this way: you have 3 apples. From this you deduce that there is such a thing as grouping of things - let's call it a set. From properties of set of elements containing 3 elements, via reasoning you deduce that such set can be split in two sets, but resulting sets will always be different in count (it can only be split like 1:2 or 2:1), if we are not allowed to split elements them selves. This rule will hold regardless if we observe 3 apples, 3 cars or 3 planets. Now comes important thing - set is not 3 apples, set is an abstraction that behaves in certain way - according to some rules, and any grouping of 3 items that obey those rules is instance of a set.

Evolution is not biological evolution, evolution is equivalent of a set - it is abstraction that follows certain rules - actually rules represent evolution (entities and relationships). All things that behave exactly by that rules is instance of evolution.

[andrew s]

1 hour ago, vlaiv said:

But in order to do so, we need a good definition what "real now

Good luck with that I have no idea even to approach it. As I said what seems ages ago I was not convinced by Lee Smolin's book.

1 hour ago, Rodd said:

 When the universe was expanding, expansion did not move through the universe, expansion happened at every point simultaneously

This is true and continues to be true for a frame of reference co-moving with the expansion (from my lecture last night the odds against anisotropic  expansion are 121,000:1) However, for any other frame of reference i.e. not co-moving moving with the expansion it did not and is not. You can see this in the CMB data collected on earth where the "raw" data has to have the dipole signal due to this motion removed. Each inertial frame picks out a specific time like slice from the 4D space-time this is the lesson of relativity. However, even in a given frame you still need a way to pick out a specific instant " a now"

1 hour ago, Rodd said:

Now pertains to everywhere.  the clock is a good example...12:00 here is 5:00 in Australia.  So we can't use the clock--but now can happen at both places--just entangle two particles and send one to Australia.   How to define "now"?  I will leave that to those of you who can write equations!

I have tried but I am not sure what you are trying to say here. Local Cock time round the world is a third use of the term time. Taking the world as being in a single reference frame then UCT (Universal coordinated time) is close to the time used as a parameter in physics.

"Now pertains to everywhere." possibly as a specific time like slice of space-time but it is frame dependant and you need a way to pick it out.

"but now can happen at both places--just entangle two particles and send one to Australia. " I need some hint by what you intend to convey by this. We discussed above that entanglement can violate naive causality but not signal causality.

I am happy with good old standard time as currently used so will leave it to others to develop the new "real time and real now"

Regards Andrew

[vlaiv]

19 minutes ago, andrew s said:

I am happy with good old standard time as currently used so will leave it to others to develop the new "real time and real now"

Are you happy with it in terms that it serves a purpose for calculations, or you are happy with it in broader terms?

I mean, problems that we are facing with explaining certain things could be a valid point that we don't understand something correctly.

For example probability - fact that there is only certainty in the past, but only probability in the future?

By broader terms I mean that you are happy with time as we currently understand it and also think that answers to questions like above will be found in different domain?

[andrew s]

12 minutes ago, vlaiv said:

Are you happy with it in terms that it serves a purpose for calculations

Yes

 

12 minutes ago, vlaiv said:

you are happy with it in broader terms?

This would be a qualified yes.

I have no problem with the current causal structure of space-time as say in SR. I don't have any issue with Probability and the transition to certainty when the results are in.

I am aware of issues in the foundations of many areas of science and mathematics e.g probability theory, statistical mechanics and QM. 

It also puzzles me that time has no operator in QM but position does but then again there is no position operator for the photon.

I am unclear if a reevaluation of what we mean or understand by time, now etc. has any role to play in this.

I am strongly prejudiced (careful choice of words) to believe that we or any other conscious entity have no role in bring about the Universe or its laws. I believe in an objective world  that exists and that we are just a part of it and have no specific importance.  (This is a personal philosophy not science. I hope stating it does not violate the forum rules.)

As a parting shot I would offer the following quote "Time is defined to make the description of motion as simple as possible" but I can't put my hand on the reference right NOW.

Regards Andrew

[Rodd]

2 hours ago, vlaiv said:

Not sure that I ever mentioned good or bad, and these labels are context sensitive - I just mentioned fitness function, without prejudice. Fitness function is case of particular game mentioned randomly chooses which chains are removed and which ones are "kept in the game". For particular fitness function - remove shorter chains with higher probability, result of evolution is that most of population is longer chains. I know that this looks kind of straight forward, but if we want more complexity we can define fitness function to include color of paper clips for example.

Try thinking in abstractions. We have one example of evolution that is ever present around us - biological evolution on earth. But that does not mean that it is only evolution based on these premises that we have identified. Think of it this way: you have 3 apples. From this you deduce that there is such a thing as grouping of things - let's call it a set. From properties of set of elements containing 3 elements, via reasoning you deduce that such set can be split in two sets, but resulting sets will always be different in count (it can only be split like 1:2 or 2:1), if we are not allowed to split elements them selves. This rule will hold regardless if we observe 3 apples, 3 cars or 3 planets. Now comes important thing - set is not 3 apples, set is an abstraction that behaves in certain way - according to some rules, and any grouping of 3 items that obey those rules is instance of a set.

Evolution is not biological evolution, evolution is equivalent of a set - it is abstraction that follows certain rules - actually rules represent evolution (entities and relationships). All things that behave exactly by that rules is instance of evolution.

Ah...but Darwinian evolution, which is what I thought we were talking about, is different than other forms of evolution because in other forms of evolution the results do not depend on survival.  The reason why this type of evolution works is because certain traits that tend to allow a species to out perform other species are propagated through selection (breeding).  In nature (not counting modern homo sapiens), the number one cause of not propagating one's species (not mating) is death (I suppose some mutations will make one being look less attractive to another and that will stifle propagation--but that is rare in and of itself  ie. attractiveness in nature usually follows traits that make individuals stronger, or faster, or more or less colorful....all things that affect success from a living/dying perspective ).   The reason why a species evolves is that a particular trait (gene or system of genes), caused by mutation or an existing structure turning advantageous due to a change in environment, provides an advantage to live (so there can be propagation).  In a non living system, there is no death, so "bad" traits can't ever really be eliminated.  besides, I still have a problem with your software.computer analogy.  In order for evolution to work there has to be propagation (either by sexual or asexual means).  I do not see how the software/computer can do this (mere replication is not good enough--otherwise crystals would be counted in, and they are not)

Rodd

[vlaiv]

8 minutes ago, Rodd said:

Ah...but Darwinian evolution, which is what I thought we were talking about, is different than other forms of evolution because in other forms of evolution the results do not depend on survival.  The reason why this type of evolution works is because certain traits that tend to allow a species to out perform other species are propagated through selection (breeding).  In nature (not counting modern homo sapiens), the number one cause of not propagating one's species (not mating) is death (I suppose some mutations will make one being look less attractive to another and that will stifle propagation--but that is rare in and of itself  ie. attractiveness in nature usually follows traits that make individuals stronger, or faster, or more or less colorful....all things that affect success from a living/dying perspective ).   The reason why a species evolves is that a particular trait (gene or system of genes), caused by mutation or an existing structure turning advantageous due to a change in environment, provides an advantage to live (so there can be propagation).  In a non living system, there is no death, so "bad" traits can't ever really be eliminated.  besides, I still have a problem with your software.computer analogy.  In order for evolution to work there has to be propagation (either by sexual or asexual means).  I do not see how the software/computer can do this (mere replication is not good enough--otherwise crystals would be counted in, and they are not)

Rodd

Let's take this one step at a time, and first let's see if we agree on following abstraction of evolution - Darwinian or other, and settle what sort of evolution are we talking about (my stance on this is that there is but one evolution as in above example with set of 3 things, and all evolutions, including Darwinian are instances of that evolution).

Evolution consists of:

- Population of entities with certain traits.

- Mutations - change in traits of any given entity that happens randomly (including formation of new traits).

- Reproduction of entities by mixing of traits in a certain way - two entities produce number of "offspring", each offspring having traits from both "parents" (this is a bit of specialization, in general case you can have any number of parents and any number of offspring).

- Fitness function that assigns probability given set of traits that any entity is able to participate in further reproduction. This function can be dynamic (change probability distribution for certain list of traits). Note that this does not include survival directly, as entity can: "die" before getting chance to reproduce, be unable to reproduce because of certain trait, or even choose not to reproduce. All of that is encapsulated in fitness function.

Is Darwinian evolution instance of above abstract evolution?

- There is population of creatures, having certain genes - traits

- Mutations happen randomly - genes get altered

- Reproduction and offspring - yes this is how it happens, we have cases of single parent, and we have cases of two parents mixing genes (traits) to provide offspring. Not sure if there is case for three or more (it might be).

- And Earth as environment produces fitness function. Creatures can be eaten - before they reproduce, they can be sterile and unable to reproduce, they can be unable to find mate in time to reproduce, they can choose not to reproduce (mostly associated with humans).

I would say, yes, Darwinian evolution is an instance of Evolution as defined above.

[humblepigeon]

On 29/11/2018 at 13:44, Rodd said:

the clock is a good example...12:00 here is 5:00 in Australia

This is only subject to the fact we set our lives based around the daylit side of the planet. There is no reason why Australia cant have the same value on their clock , its just the system we have in place to suite our biological and productiveness requirements as a species.
The problem is the speed of communication between two points at distance, which comes back to speed of information and observable events.

I think times equations may fall into place if/when particle duality is solved, as they have a number of technical similarities.

[Rodd]

9 minutes ago, humblepigeon said:

This is only subject to the fact we set our lives based around the daylit side of the planet. There is no reason why Australia cant have the same value on their clock , its just the system we have in place to suite our biological and productiveness requirements as a species.
The problem is the speed of communication between two points at distance, which comes back to speed of information and observable events.

I think times equations may fall into place if/when particle duality is solved, as they have because technical similarities.

7

My point was that even if the clock says 12 here and 5 there, there is simultaneity between the two places.  "now" is "now" regardless of what the clock says.  The event happens at 12 here and 5 there, but it happened at the same time.

Rodd

[andrew s]

2 hours ago, Rodd said:

My point was that even if the clock says 12 here and 5 there, there is simultaneity between the two places.  "now" is "now" regardless of what the clock says.  The event happens at 12 here and 5 there, but it happened at the same time.

Rodd

If you approximate the earth as an inertial frame then yes to anyone stationary on the earth. However anyone in motion relative to the earth will have a different view of what is "now". This was the key insight of Einstein which resulted in his theory special relativity. 

SR has been validated by many experiments.

Regards Andrew 

[Rodd]

8 minutes ago, andrew s said:

If you approximate the earth as an inertial frame then yes to anyone stationary on the earth. However anyone in motion relative to the earth will have a different view of what is "now". This was the key insight of Einstein which resulted in his theory special relativity. 

SR has been validated by many experiments.

Regards Andrew 

One could argue that the universe is a single reference frame.  Or the galaxy--depends on where the boundary is drawn.  Conversely, it could be said that every atom is a reference frame, as motion is different for all.   Come to think of it, every Planck length/volume fragment of the universe (the smallest possible distance/volume?) might be its own reference frame. I suppose what we should gather from Einstein is it is ALL relative.  

Rodd

[andrew s]

2 hours ago, Rodd said:

One could argue that the universe is a single reference frame.  Or the galaxy--depends on where the boundary is drawn.  Conversely, it could be said that every atom is a reference frame, as motion is different for all.   Come to think of it, every Planck length/volume fragment of the universe (the smallest possible distance/volume?) might be its own reference frame. I suppose what we should gather from Einstein is it is ALL relative.  

Rodd

We could start several new threads on this but basically yes.

But...

What makes up a suitable inertial frame is not that simple...

What the Plank length means is not settled as many would argue it's just a unit of length of no proven physical significance beyond that...

Not everything is relative.  Uniform motion is but real acceleration is not..

Regards Andrew

[Rodd]

15 minutes ago, andrew s said:

We could start several new threads on this but basically yes.

But...

What makes up a suitable inertial frame is not that simple...

What the Plank length means is not settled as many would argue it's just a unit of length of no proven physical significance beyond that...

Not everything is relative.  Uniform motion is but real acceleration is not..

Regards Andrew

I was under the impression  that the Planck length is the smallest definable length.  Its down in the quantum foam realm.  The smallest definable volume is called the Planck volume, and the smallest definable moment of time is the Planck time,. etc.  I am pretty sure I read this somewhere.  Its based, of course, on the speed of light.  The Planck length is the scale at which classical ideas of gravity and space-time break down and quantum effects (foam ) dominate.  About 1x10 -20 the size of a proton.  The Planck time is the time it would take a photon travelling at the speed of light to cross the distance equal to the Planck length.    The Planck length is definitely a real l;length--there is a formula which I am sure you know.

Rodd

[andrew s]

As I said it is not settled. Some feels as you set out above but others don't. It is speculation as we have no experimental evidence to support the quantum foam idea. I do recall some attempt to detect it via the predicted time of flight of different frequency light across large tracts of the Universe but the result was negative.

Units in physics can be quite confusing. Physicist's combine fundamental constants to give all kinds of units. As an example one book I am reading has the mass of the Sun in cm!

Regards Andrew 

[Rodd]

36 minutes ago, andrew s said:

As I said it is not settled. Some feels as you set out above but others don't. It is speculation as we have no experimental evidence to support the quantum foam idea. I do recall some attempt to detect it via the predicted time of flight of different frequency light across large tracts of the Universe but the result was negative.

Units in physics can be quite confusing. Physicist's combine fundamental constants to give all kinds of units. As an example one book I am reading has the mass of the Sun in cm!

Regards Andrew 

Not really--the Planck length is based on the principles of quantum mechanics.  At some pint, as you go downward, you will reach a size where quantum fluctuations make measurement impossible.  Beyond that point the idea of length has no meaning.  That is the Planck length.   The quantum fluctuations make it impossible to measure.  This point can be mathematically defined.  We do not need experiment.  Quantum mechanics, gravity and the speed of light define the Planck length.  None of these are questioned.

Rodd

[andrew s]

1 hour ago, Rodd said:

Not really--the Planck length is based on the principles of quantum mechanics.  At some pint, as you go downward, you will reach a size where quantum fluctuations make measurement impossible.  Beyond that point the idea of length has no meaning.  That is the Planck length.   The quantum fluctuations make it impossible to measure.  This point can be mathematically defined.  We do not need experiment.  Quantum mechanics, gravity and the speed of light define the Planck length.  None of these are questioned.

Rodd

 QFT is based on the continuum space-time of Special Relativity.  I assume you are referring to the Heisenberg Uncertainty principle but that puts limits on measuring pairs of non commuting "variables"  not on a specific variables measurement.  There are of course experimental errors which currently are way above the Plank scale but see blow.

There are speculative theories of Quantum Gravity which propose space-time is not a continuum at the smallest scale.  None of these has any experimental support  and/or attract broad acceptance outside of the competing groups.

This is a reasonable summary on the Quantum Foam https://en.wikipedia.org/wiki/Quantum_foam . This https://www.openu.ac.il/personal_sites/yoni-granot/papers/LIV_NaturePhysics2015.pdf is one of the references that sets experimental constraints on the scale of any Quantum Foam below the "Plank scale" but I need to read it more closely to make sure I fully understand it. 

Regards Andrew

PS Do you have a reference to support this "At some pint, as you go downward, you will reach a size where quantum fluctuations make measurement impossible." as I would like to follow it up?

[George Jones]

2 hours ago, andrew s said:

PS Do you have a reference to support this "At some pint, as you go downward, you will reach a size where quantum fluctuations make measurement impossible." as I would like to follow it up?

 

I think that there is a hand-waving argument for this, and the argument does involve non-commuting operators. Annihilating the vacuum and then trying to produce a quantum particle is different than creating a quantum particle from the vacuum and then annihilating that particle. Tentatively, my project for tomorrow morning is to see whether I can make heads or tails of this argument.

Time for a groan.

Q: Why don't matrices live in the suburbs?

A: They don't commute.

 

[Rodd]

1 hour ago, George Jones said:

 

I think that there is a hand-waving argument for this, and the argument does involve non-commuting operators. Annihilating the vacuum and then trying to produce a quantum particle is different than creating a quantum particle from the vacuum and then annihilating that particle. Tentatively, my project for tomorrow morning is to see whether I can make heads or tails of this argument.

Time for a groan.

Q: Why don't matrices live in the suburbs?

A: They don't commute.

 

Just google Planck length.  That statement is born out of the Planck length being defined at the size where quantum fluctuations are greater than any possible measurement.  I know this....the Planck length is defined in physics and is accepted to be real by all.  It even has a numerical number associated with it.  I am paraphrasing.  

Rodd

 

The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate. This is the �quantum of length�, the smallest measurement of length with any meaning. And roughly equal to 1.6 x 10^-35 m or about 10^-20 times the size of a proton.

What is Planck length? What is Planck time? - PhysLink.com

 

https://www.physlink.com/education/askexperts/ae281.cfm

[Rodd]

6 minutes ago, Rodd said:

A: They don't commute.

They Transmute!

[andrew s]

5 hours ago, Rodd said:

Just google Planck length.  That statement is born out of the Planck length being defined at the size where quantum fluctuations are greater than any possible measurement.  I know this....the Planck length is defined in physics and is accepted to be real by all.  It even has a numerical number associated with it.  I am paraphrasing.  

Rodd

 

The Planck length is the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate. This is the �quantum of length�, the smallest measurement of length with any meaning. And roughly equal to 1.6 x 10^-35 m or about 10^-20 times the size of a proton.

What is Planck length? What is Planck time? - PhysLink.com

 

https://www.physlink.com/education/askexperts/ae281.cfm

I have, I have looked at this and other links did you look at mine?

The fact remains there is no evidence for these assertions being true. It is a widely held belief by Physicists but is just that.

I don't think I will convince you or you me so I propose we leave it here.

Regards Andrew 

[andrew s]

6 hours ago, George Jones said:

 

I think that there is a hand-waving argument for this, and the argument does involve non-commuting operators. Annihilating the vacuum and then trying to produce a quantum particle is different than creating a quantum particle from the vacuum and then annihilating that particle. Tentatively, my project for tomorrow morning is to see whether I can make heads or tails of this argument.

Time for a groan.

Q: Why don't matrices live in the suburbs?

A: They don't commute.

 

Hi George, I look forward to this. Can you provide a link when you come back on this, please.

I hope it is not the same hand waving that leads to an overestimation of the cosmological constant by 60 orders of magnitude! ?

Regards Andrew 

[Rodd]

7 hours ago, andrew s said:

I don't think I will convince you or you me so I propose we leave it here

Agreed.  I will end by saying that if you believe in quantum mechanics and quantum fluctuations, then there HAS to be a size where these dominate.  I don't think that can be argued.  Since quantum mechanics is accepted by everyone (even Einstein), I don't see the problem.  The theory has been correct, along with relativity) where it has been tested.  A bit of extrapolation is permitted.   After all--if we take the evidence thing to the end, we can say that there is no real evidence that subatomic particles exist.  All we have are trace lines in an accelerator print out that the computer tells us must be a boson, because of its shape and position.  We can't hold it, look at it, any more than we can hold a quantum fluctuation.  But we say "It is Real".  The evidence is in the mathematics, and the Planck length is strewn throughout physical computations.  In fact, I find it surprising that there is someone who does not believe in the Planck length.  Never heard of that before.  But hey, maybe your right.

Rodd

[humblepigeon]

Appologies Rodd, i thought it was a bit obvious
Fascinating subject, especially when you think in depth at what 'NOW' actually means.

22 hours ago, Rodd said:

Come to think of it, every Planck length/volume fragment of the universe (the smallest possible distance/volume?) might be its own reference frame.

Do you refer to Frame like a step of events rodd? a snapshot of a sequence? This i find interesting, as frame gives us a universe with a direction.

We could also think of 'NOW' as being a 'State', rather than as a Frame of time. Coming from a computer programming perspective here. If time was a State instead of a sequence, it has no inertia until the next given event triggers the new 'NOW' as it were.
If we have a State of time and not a single event occured in the universe (no measurements can be observed), therefore time would stop !?

Or, what if time is just a by product of our own self awareness. Is a Cow aware of time ?
Just some thoughts.

[George Jones]

16 hours ago, Rodd said:

Just google Planck length.

 

10 hours ago, andrew s said:

Hi George, I look forward to this. Can you provide a link when you come back on this, please.

While I certainly do use links found by Google, I also like to make extensive use of my own personal library of university-level (and beyond) physics and math books (more than 500). in this case, my plan (which may change)  is to learn the material in the first two sections of chapter 7 "Scalar Fields and the vacuum fluctuation" from the book "Cosmological Inflation and Large-Scale Structure" by Liddle and Lyth.

 

10 hours ago, andrew s said:

I hope it is not the same hand waving that leads to an overestimation of the cosmological constant by 60 orders of magnitude! ?

Largely the same argument. A quote by David Griffiths, whose books are used ubiquitously to teach physics courses (we use two of them): "In general, when you hear a physicist invoke the uncertainty principle, keep a hand on your wallet."

 

3 hours ago, Rodd said:

I will end by saying that if you believe in quantum mechanics and quantum fluctuations, then there HAS to be a size where these dominate.  I don't think that can be argued.

I think that you need to take some care, as you seem to have shouted this from on high without referencing any actual arguments.

 

3 hours ago, Rodd said:

We can't hold it, look at it, any more than we can hold a quantum fluctuation.  But we say "It is Real".  The evidence is in the mathematics, and the Planck length is strewn throughout physical computations.

No one is arguing that the Planck length does not exist as a mathematical quantity (i.e., there is a combination of c, G, and h that has units of length). Physicists eventually need more than mathematical evidence.

 

3 hours ago, Rodd said:

In fact, I find it surprising that there is someone who does not believe in the Planck length.  Never heard of that before.  But hey, maybe your right.

Over the last twenty-five years, I have worked with many physicists at several universities. Most professional physicists have never worked through a Planck scale argument, so they don't "believe" anything one way of the other; they are agnostic. High energy physicists constitute a (vocal) minority of professional physicists.

I have taught university lecture courses in quantum theory dozens of times (most recently, a first introduction to quantum theory in Sept. - Dec. 2017, and a course in advanced quantum mechanics for physics Master's students in Jan. - April 2018), and while I find Planck scale arguments to be interesting, I do not find them to be compelling.

Now to start reading.