[Bill S (OP)]

I think the idea that 'reality' is a bad starting point is very important.

Would it be fare to paraphrase/extend this to say something like:

     “Reality” is not the best starting point for thinking about the quantum world.  This would not be because the quantum world is “unreal”, but because our concept of reality is founded in our perception of the macroscopic Universe. 

[Bill S (OP)]

Instead of  trying to think about a discrete point particles, consider two intersecting infinite (but not evenly distributed) blobs that are going to interact somewhere within their intersection. "Before" the interaction occurs, the best we can do is offer up a probability distribution of where the most likely times and places of the interaction will be, based on information we have about the histories or environments of these blobs. The "time" and "location" of this interaction do not mean that two point particles collided at that precise time and place. No, it merely means that this is when and where the two blobs interacted--no more, no less.

I’m impressed.  Even I can visualise this.  I’m struggling with one aspect, though.  It has a ring of familiarity to it. 

By “infinite blobs” do you mean:

1. They occupy the entire Universe, or
2. They might occupy the entire Universe, but we don’t know, until an observation is made?

If 1, do we run into the problem of FTL communication when an observation is made?
If 2, do we not have the same problem of mutual location that we had with particles, just on a different scale?

[Bill S (OP)]

I view Copenhagen as a set of rules for using a methodology that gives amazingly accurate answers, but like most analogies and methodologies these rules can be overextended to give even greater confusion.

Would you consider that maintaining that the Copenhagen interpretation holds that there is no “reality” before observation is an “overextension”?   It seems to have been fundamental to Bohr’s original concept.

[Bill S (OP)]

Heisenberg's indeterminacy is mathematically obvious, and no more than a correct formulation of Zeno's paradox. Speed is Δx/Δt, position is x. The larger we make  Δx and Δt, the more precisely we can measure their ratio, but the less meaning we can assign to either x or t. The clever bit is mixing in mass, then guessing that ΔpΔx ≥ h, so whilst we might have a very good idea of the position of a cannonball at any given moment, it becomes very difficult to locate an atom or an electron as m decreases. Ultimately this explains why the hydrogen atom has a finite (but fuzzy) diameter instead of collapsing, and to everyone's surprise h turns out to be a universal constant.

Heisenberg’s example of the photon hitting the electron seems to suggest that it is the inadequacy of the measuring device that “creates” the uncertainty.  My understanding is that uncertainty is more fundamental to QM, and that however much we might improve our measuring instruments, we will never achieve "certainty".  Would I be right in interpreting your post as agreeing with that?

[chiralSPO]

Instead of  trying to think about a discrete point particles, consider two intersecting infinite (but not evenly distributed) blobs that are going to interact somewhere within their intersection. "Before" the interaction occurs, the best we can do is offer up a probability distribution of where the most likely times and places of the interaction will be, based on information we have about the histories or environments of these blobs. The "time" and "location" of this interaction do not mean that two point particles collided at that precise time and place. No, it merely means that this is when and where the two blobs interacted--no more, no less.

I’m impressed.  Even I can visualise this.  I’m struggling with one aspect, though.  It has a ring of familiarity to it. 

By “infinite blobs” do you mean:

1. They occupy the entire Universe, or
2. They might occupy the entire Universe, but we don’t know, until an observation is made?

If 1, do we run into the problem of FTL communication when an observation is made?
If 2, do we not have the same problem of mutual location that we had with particles, just on a different scale?

I would say statement 1 is more in line with my understanding. I suspect that statement 2 runs afoul of "hidden variables," which have been shown to be highly improbable by several experiments, known collectively as Bell tests (https://en.wikipedia.org/wiki/Bell_test_experiments).

I don't think that we need to worry about FTL communication, though... the information gained from the interaction will propagate no faster than c.

[Bill S (OP)]

I don't think that we need to worry about FTL communication, though... the information gained from the interaction will propagate no faster than c.

If the "blobs" occupy the entire Universe until they interact.  Then, at the instant of impact, they cease to occupy the entire Universe, how does the distant part know that it should no longer occupy that space?

[guest4091]

Some of these points were mentioned, but I'll elaborate.

The Copenhagen Interpretation of quantum theory holds that there is no reality at a quantum level, without observation

.
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This is true at all levels of observation.
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Heisenberg, in developing his case for the uncertainty principle, used the example of “observing” an electron by hitting it with a gamma ray photon.  This act established the location of the electron, at the instant of contact, but gave no information about its velocity.

Bohr used this same example in defending complementarity; arguing that it supported the contention that “observation” created reality, in the quantum realm. The reasoning seemed to be that the electron had neither position, nor velocity, until an observation was made.

---
Back to basics for a minute. Position and velocity are not properties of a particle. They are relations/descriptions used in human observations for the purpose of understanding the behavior of the world we inhabit, in terms of the model the mind has formed. I.e. they are part of perception, reality confined to the mind. Determining velocity requires two observations to establish a time and space interval, for calculation. One observation gets you an historical position, with no velocity information. The second observation gets you a 2nd historical position. The velocity calculation is made. Now you know where the particle was, and what the velocity was.

There must be a distinction made between a thing as it exists in the physical world, and the perception of that thing, just as with Claude and an image of Claude. The mind is an  image processing system. Looking at the rings of Saturn through a telescope, we know we aren't 'really' that close, but the images have been manipulated to simulate being closer.
There must also be a distinction made between a thing as it exists in the physical world, and our knowledge of that thing. At the moment, I don’t know with certainty if the Eiffel Tower is still standing, unless the media informs me of a terrorist plot to bring it down. Our knowledge is always historical and with a degree of uncertainty.

I would expect the predictive accuracy of quantum physics to be accurate, since it's based on actual historical events or statistics. Similar to what the weather people do.
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This must raise the questions: What was the gamma ray photon aimed at?  And, what did it hit, if the electron was not there before it was hit?

---
These type of experiments involve selective targeting of samples. You can research CERN, which has multiple projects in process.

[Bill S (OP)]

The Copenhagen Interpretation of quantum theory holds that there is no reality at a quantum level, without observation.

This is true at all levels of observation.

Are you saying that without observation, there is nothing there; or that without observation there is no way of knowing what, if anything, is there?

Back to basics for a minute. Position and velocity are not properties of a particle. They are relations/descriptions used in human observations for the purpose of understanding the behavior of the world we inhabit,

Should this be interpreted as saying that Heisenberg was not justified in drawing the conclusion he did from his analogy?

[alancalverd]

Heisenberg’s example of the photon hitting the electron seems to suggest that it is the inadequacy of the measuring device that “creates” the uncertainty.  My understanding is that uncertainty is more fundamental to QM, and that however much we might improve our measuring instruments, we will never achieve "certainty".  Would I be right in interpreting your post as agreeing with that?

Not "inadequacy" but  an entirely inescapable consequence of measurement. Actually I'm not sure this example is correctly attributed to WH, whose appreciation of indeterminacy was a lot deeper.

Certainty is undefined. What we know (with absolute certainty!) is that either ΔpΔx ≥ h, or the universe would collapse to a singular point. It hasn't, and we have a pretty good idea of the value of h. 

[Bill S (OP)]

Actually I'm not sure this example is correctly attributed to WH, whose appreciation of indeterminacy was a lot deeper.

Your doubts may be well founded.  I understand it was Bohr who brought this to "public" attention at a Physics Conference in about 1928.  Bohr was notoriously easily misunderstood, so the whole thing may be apocryphal.   

Certainty is undefined. What we know (with absolute certainty!) is that either ΔpΔx ≥ h, or the universe would collapse to a singular point. It hasn't, and we have a pretty good idea of the value of h. 

Thinks for clarifying that.  All I have to do now is work out why the Universe would collapse. 

[guest4091]

Bill S;

Are you saying that without observation, there is nothing there; or that without observation there is no way of knowing what, if anything, is there?

Knowledge is dependent on sensory input which is analyzed by the brain/mind. Sensory input is predominately visual. Photons are often referred to as 'messenger particles'  since that is one role they play on behalf of the observer. Observation does not cause a material object to exist, but It does make you aware of it's presence. 

Should this be interpreted as saying that Heisenberg was not justified in drawing the conclusion he did from his analogy?

No scientist should expect to get velocity information from one observation/probe. That is basic physics.
When lasers reflect off the moon, informing them it is creeping away at 1 inch/year, the observation does not alter the state of the moon in any significan/detectable manner.
At the quantum scale of events, the energy of the probes is on an equivalent scale as the object being probed. Like swinging at a baseball with a bat vs a fly swatter The reality he speaks of is our knowledge of the state. The particle has a state, no one knows what it is.
It's not confined to the quantum level.
When you insert a thermometer into a liquid, the device temperature adjusts to the liquid.
Flip a coin. In the air it's H and T, until it lands and becomes H or T. You still have to look to know the outcome.
The uncertainty is not in Schrodingers cat, but in the radioactive sample.
I added that because it seems there is a confusion between things and the perception of things. Science is moving toward more abstract ideas.

[Bill S (OP)]

Flip a coin. In the air it's H and T, until it lands and becomes H or T. The coin has the “qualities” of H & T, throughout.

  Are you saying that, for example, an electron has position and momentum before observation?

This has some interesting things to say about wave/particle duality and the role of observation, which may be relevant to this thread.

https://www.sciencealert.com/reality-doesn-t-exist-until-we-measure-it-quantum-experiment-confirms

[PmbPhy]

There are two things to consider here (1) what does a measurement consist of and (2) what does the system being observed consist of.

Things like Compton scattering are often treated classically so there's no wave function or worry about when a measurement is made or what state the system is in. And when you do use quantum mechanics you have to use quantum electrodynamics.

The other thing to consider is what an observation/measurement is. An observation is made when a microscopic system interacts with a macroscopic system, the results of which can be recorded on/by the macroscopic system.

[yor_on]

Enjoy reading you Phyti

[guest4091]

The coin has the “qualities” of H & T, throughout.

That is not part of my post
.
If we assume an object persists unless it's destroyed (conservation principle) then it's somewhere, and has a position IF we choose measure it.
If it's not somewhere, the conservation principle is violated.
It still reduces to our knowledge about the object.

As to the article you cited, What is the definition of 'reality'?

[alancalverd]

Certainty is undefined. What we know (with absolute certainty!) is that either ΔpΔx ≥ h, or the universe would collapse to a singular point. It hasn't, and we have a pretty good idea of the value of h. 

Thinks for clarifying that.  All I have to do now is work out why the Universe would collapse. 

Easy. If ΔpΔx = 0, every electron will spiral in to the nucleus of its atom, emitting a continuous spectrum of electromagnetic radiation as it does so. That's just classical electrostatics and  electrodynamics, and is the Achilles heel of  the classical Bohr atom.

As h > 0, there are finite solutions to the Schrodinger equation and thus nonzero orbital dimensions and shapes, with quantised energy differences between them. Hence a noninfinitesimal universe, the hydrogen bond, stereochemistry, and us. Though the existence of politicians, philosophers and priests still baffles me. What are they for?

[Bill S (OP)]

Instead of trying to think about a discrete point particles, consider two intersecting infinite (but not evenly distributed) blobs that are going to interact somewhere within their intersection. "Before" the interaction occurs, the best we can do is offer up a probability distribution of where the most likely times and places of the interaction will be, based on information we have about the histories or environments of these blobs.

I like your "blobs", but have some questions.

According to Copenhagen; do they exist before you observe them?
If they don't; what is there to observe?
If they do; how do you know, if you have not observed them?

[chiralSPO]

My understanding is that they exist, they are just undefined (you don't have information about them).

I don't believe that anyone with a firm understanding of physics would claim that the universe ceases to exist when we close our eyes to it. Similarly, it is not that matter goes into and out of existence depending on whether we have our instruments turned on. But it is at least somewhat reasonable to claim that a particle is not located anywhere if there are no ongoing interactions with which to locate it.

Another important point, that has been mentioned in this thread, but not explicitly focused on is this: Nothing can ever be known exactly--there is always some uncertainty. And it is also rare that there is zero information available about something. So asking about the existence of something in the case in which nothing is known about it, is really an extreme case.

[Bill S (OP)]

.... Nothing can ever be known exactly--there is always some uncertainty. And it is also rare that there is zero information available about something....

 Wouldn't it be true to say that if nothing can ever be known exactly; it would not be "rare" to have "zero" information about something, as that would leave no room for uncertainty?

Pedants of the world, unite!  []

[chiralSPO]

.... Nothing can ever be known exactly--there is always some uncertainty. And it is also rare that there is zero information available about something....

 Wouldn't it be true to say that if nothing can ever be known exactly; it would not be "rare" to have "zero" information about something, as that would leave no room for uncertainty?

Pedants of the world, unite!  []

Indeed. I wanted to say it was impossible to have zero knowledge about something--on the other hand, my experience indicates that it is entirely possible for people (not you) to have zero knowledge...