Realism in QM: Existing Before Measurement?

In summary: Thread closed.In summary, the conversation revolves around the concept of realism in the context of the measurement problem and Bell inequality violations in quantum mechanics. While there are various definitions of realism, it generally means that a universe obeying physical laws continues to exist even after all observers have died. However, in the Copenhagen interpretation, the electron does not have a location until it is measured, which is an example of an anti-realist interpretation. In realist interpretations, the electron is believed to have a location before it is measured, but this is still an assumption with consequences that must be accepted. The conversation also discusses the importance of defining terms and doing research before discussing these complex concepts.
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I think it's the idea that things exist even before we measure them, correct?
 
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There are many different definitions, depending on who is using the word and in what context.

In the context of the measurement problem, "realism" usually means that a universe obeying physical laws continues to exist even after all observers have died.

In the context of Bell inequality violations,"realism" may mean "have a deterministic explanation", eg. http://arxiv.org/abs/0909.0015.
 
  • #3
Nick V said:
I think it's the idea that things exist even before we measure them, correct?

There are several related concepts floating around under the general name "realism", and if you search this forum for previous threads you'll find several of them. It's generally a bad idea to use the word without also stating exactly what you mean by it - and if you search this forum for previous threads you'll also find plenty of examples of this :)

The starting point has to be the discussion of "elements of reality" in the EPR paper, which we've already pointed you at several times. You should also find a precise definition of "counterfactual definiteness" (google and searches here will be helpful).

This thread will be summarily closed if your next post in it does not show some evidence that you have done this investigation and that you have also read any responses posted to the thread by the science advisors.
 
  • #4
atyy said:
There are many different definitions, depending on who is using the word and in what context.

In the context of the measurement problem, "realism" usually means that a universe obeying physical laws continues to exist even after all observers have died.

In the context of Bell inequality violations,"realism" may mean "have a deterministic explanation", eg. http://arxiv.org/abs/0909.0015.
Does it contribute to the idea that electrons have a location, even before we measure/observe them?
 
  • #5
Nick V said:
I think it's the idea that things exist even before we measure them, correct?
And how would you know "that things exist" if you don't observe them? I will be very disappointed with PF if this thread drags on.
 
  • #6
samalkhaiat said:
And how would you know "that things exist" if you don't observe them? I will be very disappointed with PF if this thread drags on.
In copenhagen interpretation, the electron literally has no location prior to measurement. This is an example of an anti realist interpretation.
 
  • #7
Nugatory said:
There are several related concepts floating around under the general name "realism", and if you search this forum for previous threads you'll find several of them. It's generally a bad idea to use the word without also stating exactly what you mean by it - and if you search this forum for previous threads you'll also find plenty of examples of this :)

The starting point has to be the discussion of "elements of reality" in the EPR paper, which we've already pointed you at several times. You should also find a precise definition of "counterfactual definiteness" (google and searches here will be helpful).

This thread will be summarily closed if your next post in it does not show some evidence that you have done this investigation and that you have also read any responses posted to the thread by the science advisors.
Ok,what I mean is, in realist interpretations of QM, does an electron have a location before it is measured? In copenhagen interpretation (anti realist) it doesn't have location until it is measured. But what about realist interpretations?
 
  • #8
Nick V said:
In copenhagen interpretation, the electron literally has no location prior to measurement. This is an example of an anti realist interpretation.
You asked about REAL THINGS, did you not? The coordinates of the electron (i.e. its location) IS NOT a real thing. Apples and chairs are real things.
 
  • #9
samalkhaiat said:
You asked about REAL THINGS, did you not? The coordinates of the electron (i.e. its location) IS NOT a real thing. Apples and chairs are real things.
Isn't that only according to the copenhagen interpretation?
 
  • #10
Nick V said:
Isn't that only according to the copenhagen interpretation?
That is according to PHYSICS. I don't talk "interpretation".
 
  • #11
samalkhaiat said:
And how would you know "that things exist" if you don't observe them?
You don't. Instead, the claim appears an assumption and the interpretations which make that assumption are classified as "realist". Of course this assumption has consequences that must be accepted along with the assumption. (This remark is for the OP - Samalkhaiat already understands this).

I will be very disappointed with PF if this thread drags on.

When it's dragged along enough to bother you... report it! We mentors are extraordinarily powerful, but our clairvoyance is still a bit weak compared with some of our other superpowers - If no one reports it, we may assume that no one is bothered by it yet.
 
  • #12
Nugatory said:
You don't. Instead, the claim appears an assumption and the interpretations which make that assumption are classified as "realist". Of course this assumption has consequences that must be accepted along with the assumption. (This remark is for the OP - Samalkhaiat already understands this).

But isn't that what realist interpretations of QM are? That electrons have a location before it is measured?
 
  • #13
Nick V said:
But isn't that what realist interpretations of QM are? That electrons have a location before it is measured?

I said "This thread will be summarily closed if your next post in it does not show some evidence that you have done this investigation".

We're there.
 

1. What is the concept of realism in quantum mechanics?

Realism in quantum mechanics refers to the idea that physical properties of objects exist independently of our observations or measurements. It suggests that a particle or system has definite properties, such as position or momentum, even when we are not observing or measuring it.

2. How does the concept of realism relate to the measurement problem in quantum mechanics?

The measurement problem in quantum mechanics arises when we try to explain the contradictory behavior of particles at the quantum level. Realism suggests that particles have definite properties even when we are not measuring them, but the act of measurement in quantum mechanics affects the state of the particle, making it difficult to reconcile with realism.

3. Is there evidence to support the idea of realism in quantum mechanics?

There is currently no scientific evidence to definitively prove or disprove the concept of realism in quantum mechanics. Some interpretations of quantum mechanics, such as the Copenhagen interpretation, reject the idea of realism, while others, such as the many-worlds interpretation, support it.

4. What is the role of consciousness in realism in quantum mechanics?

Some interpretations of quantum mechanics, such as the Copenhagen interpretation, suggest that the act of measurement or observation by a conscious observer is necessary for a particle to have definite properties. However, other interpretations, such as the many-worlds interpretation, do not require consciousness to play a role in the existence of properties.

5. Can realism in quantum mechanics be reconciled with other theories, such as relativity?

There is currently no widely accepted theory that can fully reconcile realism in quantum mechanics with other theories, such as relativity. This is known as the measurement problem and is one of the major challenges in the field of quantum mechanics.

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