# Resolving the measurement problem with mathematical theorems? [closed]

The key debate, around the measurement problem is whether collapse should be interpreted as a physical process(Bohmian Mechanics) or as an immaterial process(e.g. Copenhagen Interpretation, Consciousness causes collapse, etc.). It has been confirmed that wave function collapse happens instantaneously. I think one way to resolve this issue could be to construct a mathematical theorem which demonstrates that physical causality always takes time to occur or at a finite speed. By determining that it is impossible for physical causation to take place instantaneously, one could then infer that the process of wave function collapse is non physical and one can thus eliminate interpretations with a physical mechanism for collapse. Do you think that it is possible to construct such a mathematical theorem?

• quantamagazine.org/… Apr 18 '20 at 11:54
• Consciousness causes collapse The Copenhagen Interpretation does not say this. Apr 18 '20 at 12:49
• I was trying to say that Copenhagen and consciousness causes collapse are different interpretations. Apr 18 '20 at 12:53
• You do not need any such theorem. That causality is limited by the speed of light if already a thing in physics: en.wikipedia.org/wiki/… Apr 18 '20 at 15:26
• "It has been confirmed that wave function collapse happens instantaneously." Please provide a reference for that claim, because literature with superconducting circuits in the last ten years seems to prove that this is not true. Apr 18 '20 at 16:37

One does need to specify a bit more about what one means by the Copenhagen interpretation. There is the form involving Bohr's notion of complementarity, in which some form of physical reality is ascribed to wave functions (this is so vaguely expressed that might even include Bohmian mechanics), and there is what Jeffrey Bub calls the the orthodox interpretation, or Dirac-Von Neumann interpretation, in which the wave function is only an expression of probability, and, like any probability, exists only in the mind of the observer.

I think one way to resolve this issue could be to construct a mathematical theorem which demonstrates that physical causality always takes time to occur or at a finite speed.

This theorem already exists in quantum electrodynamics (and by implication in quantum mechanics generally). It is the locality, or microcausality condition, and it is necessary to obtain unambiguous probabilities.

There are other approaches too. It is an undeniable principle that in many repetitions of an experiment, we should expect a certain relative frequencies for each possible result. From this one can construct the whole mathematical structure of quantum mechanics as a probability theory for indeterminate processes, including the principle of superposition and the derivation of the Schrodinger equation from which apparent interference effects arise. This shows that there is nothing more mysterious to wave function collapse than the change to probability when information becomes known.

In my view, this means that the measurement problem has already been resolved by mathematical theorems; we already have a unique consistent interpretation. The continuing argument is not resolved by mathematics any more than the deniers of relativity recognise Einstein's mathematical arguments, and is not different in principle than e.g. argument over Dingle's fallacies. If there is a difference it is that the mathematical foundations of quantum mechanics involves more advanced mathematics and is accessible to fewer people.

I have given a complete treatment to clarify the orthodox interpretation in The Hilbert space of conditional clauses

• “ the wave function is only an expression of probability, and, like any probability, exists only in the mind of the observer.” Nice not only to think it, but to say it out loud. Einstein would be proud of that. Apr 19 '20 at 8:00
• @HolgerFiedler, Not really. It is the accepted view of most statisticians, and was expressed by James Clerk Maxwell "... the true logic for this world is the calculus of Probabilities, which takes account of the magnitude of the probability which is, or ought to be,in a reasonable man’s mind". Apr 19 '20 at 8:26