For and Against the Copenhagen Interpretation

  • I
  • Thread starter Lynch101
  • Start date
  • #26
Lynch101
Gold Member
384
31
Please do not clutter the thread with further discussion of the mind-body problem. That is off topic for this discussion. Please focus on the OP question, which was about the pros and cons of the Copenhagen Interpretation of QM.
Thank you for your efforts in trying to keep this on topic.

My original thinking was to start a thread for each of the interpretations and see what arguments there are for and against each of them, but I recently discovered your insights article The Fundamental Difference in Interpretations of Quantum Mechanics and I think that frames the question I had in mind, in a much more concise manner. Would it be OK to start a new thread on the pros and cons of instrumentalist interpretations vs non-instrumentalist ones?

Your article gives great insight into the question but I would love to ask a few more questions in that direction. I don't want to spam the forum with multiple threads but the thread title of this wouldn't really capture the broader question.
 
  • #27
PeterDonis
Mentor
Insights Author
2019 Award
31,641
10,383
Would it be OK to start a new thread on the pros and cons of instrumentalist interpretations vs non-instrumentalist ones?
As long as you're specific about which interpretations fall into each category, that should be OK. Giving specific references to support your classification of the interpretations would also be very helpful; I'm not sure there is a single "standard" version of any interpretation, so it's always good to give a specific reference to whatever source you are using as a basis for your understanding.
 
  • #28
52
19
Regarding the pros, my feeling is the success, one way or the other, is the success of the Schrödinger equation. The problem with it, as I see it, is that the variable is ψ, which leaves open the question, what does it represent. Copenhagen takes the Born interpretation wherein ψ.ψ* represents probability, but while this is generally successful I dispute it is a pro because often it leads to the need for renormalization, and while I understand this need, I feel it is a bit of a fudge. I would be curious to know what others think of this. The fact it does not postulate hidden variables is an advantage but I still think there are uncomfortable aspects and I think every interpretation has the odd dead rat that must be swallowed. I don't see the fact that it complies with the mathematical formalism as an advantage because the formalism could be argued to be a means of carrying out calculations, and is therefore not really part of the interpretation. No formalism would be acceptable if it did not give correct answers.

As for the cons, I don't really see the measurement problem as a con, but rather just that - a problem. As I see it, measurement is not part of the interpretation - you cannot formulate an operator for ψ. However, the cat is a problem. To simplify the problem as I see it, and maybe someone can explain, if I see the cat alive and if A is an amplitude of ψ, and let me oversimplify, I can write P (probability)= (A^2) = 1. If I see a dead cat, I write P= (D^2) = 1. If I put the cat in the box, and oversimplifying to illustrate, classically I would write P = (A^2 + D^2)/2 =1, i.e. there is one cat and we don't know. But with this interpretation, it seems we write P = (A^2 + D^2 + 2AB)/x = 1. This is because we add amplitudes, not probabilities, and x renormalizes. What bothers me is, in this example, what does 2AB represent physically? Maths is clear, and in this oversimplified state I would assume x = 4, but it leaves the cat a quarter alive, a quarter dead and half something else. Which leaves two problems when I open the box. One is well-known - the so-called collapse of the wave function (where do the other probabilities go?), but what happens to the "something else"? It obviously disappears, but how does it know to disappear. If we replace cats with spin we have the question, what is the angular momentum contribution of the 2AB? If the wave interference is physical, then the total angular momentum "disappears" until measurement, although if it is statistical, it is, "before measurement we did not know, after, we did" which is the Einstein view, but that is not part of Copenhagen.

Just thinking. Maybe not clearly enough. Anyone care to help?
 
  • Like
Likes Lynch101
  • #29
EPR
236
39
These type of questions will likely not be resolved in the current framework.
'Particles' are a set of relationships in SR and QFT. Although we can make statistical predictions, we seem to be missing a huge part of the underlying mechanism which leads to definite outcomes. This isn't something minor that can be overlooked.
I doubt any interpretation is even close to how this comes about(and the Copenhagen rightly says almost nothing about it which i find it's not a real interpretation per se).
 
  • Like
Likes Lynch101

Related Threads on For and Against the Copenhagen Interpretation

Replies
45
Views
9K
  • Last Post
Replies
11
Views
1K
  • Last Post
Replies
5
Views
3K
Replies
1
Views
2K
Replies
8
Views
2K
Replies
8
Views
206
Replies
8
Views
3K
Replies
5
Views
3K
Replies
32
Views
7K
Replies
12
Views
1K
Top