Why does the Copenhagen interpretation assert randomness if this cannot be tested?

Question

Why does the Copenhagen interpretation of QM assert that random events occur if such a claim cannot ever be proven or disproven?

A related question:

How to tell if QM is really random?

Edit On second thought it could certainly be disproven. It couldn't, to my understanding, be shown that randomness as Copenhagen asserts is provable in any sense of statistical significance. Is this true? If it is, why does Copenhagen assert randomness instead of asserting that no non-disprovable deterministic rules are known?

Edit 2: I've created a proper place for arguing about what an interpretation is:

What is an interpretation of quantum mechanics?

Answer 1

We do experiments and come up with distributions of the variables that can be measured.

There exists a very deterministic theory, Quantum Mechanics, that predicts accurately probability distributions for our measurements and the theory is continuously validated.

Probabilities exist in the classical physics regime and mean exactly the same thing as the probabilities measured and fitted with quantum mechanical solutions.

Assuming randomness is on the lines of KISS (keep it simple stupid). If there were not all these people trying to find a classical framework underneath the quantum mechanical probabilities there would be no need for the assertion of randomness, it would be self evident, as it is for the throws of dice.

So it is the theories that assert the existence of deterministic underlayers for quantum mechanics that, by contrast, force an "assertion" of randomness. If quantum mechanical probabilities could be shown to be biased (the way a dice can be biased by cleverly weighting it) then new standard models and theories would be developed. At the moment as far as I know deterministic underlayer theories have problems with Lorenz invariance, which is another well validated theory of particle physics.

Answer 2

I must contradict anna v and acouriousmind.

Firstly, I agree: The physical everyday work is determined by experiments and calculation and not by interpretation.

But we sent out physicists to come back with results. Certainly they shall calculate, apply rigor, but do not forget the reason why you are working! The KISS-(keep-it-simple-stupid)-argumentation confesses incapacity and seems to be an attempt to dispense physics from its initial task.

Knowledge is not only the physical experiment and the physical calculation but also their corresponding interpretation. If you would remove interpretation (and in particular: Copenhagen interpretation) there would be left a gap. Interpretation is not only needed for the public but also for other physicists which are working on other topics. A gravitation specialist needs an idea about quantum nonlocality, even if he is not following the same physical concept.

Copenhagen, many worlds, hidden variables and guide wave are more than simple speculation. Each of them is one view of one aspect of quantum nonlocality, and they are probably complementary, each of them including one part of the truth, which we are not able to find by experiments. They have been developed by the most competent physicists, and they have been maintained for many decenniums. To say with a handwave that they are not part of physics seems to be rather shortsighted. Without these interpretations no substantial knowledge about nonlocality would be left.

In short: Sometimes we can say "B follows from A". But sometimes our knowledge is only: "B seems to follow from A" or even, in the worst case "One possible explanation of A might be B". These are no empty phrases. They are part of physical knowledge.

Answer 3

[Disclaimer: this is a personal view. It is not necessarily reflective of what physicists at large think, nor is it accepted canon]

Interpretations are what happens when people forget what science is all about. With all that we know, with all that we have found out to predict the world, we tend to assign reality to concepts like operators or wavefunctions. But at the end of the day, all that matters is predicting what is observed. And none of the interpretations of QM differ about that. They muse endlessly about what is real and what may be derived, but there is no empirical way to distinguish between a world with non-local hidden variables and a world that is random, but local. And Bell's theorem tells us that there is no deterministic theory that could ever reproduce quantum behaviour from locality and determinism.

In that spirit

"Shut up and calculate"

is really what it is all about. Science is empty if it doesn't produce testable results. And if two approaches generate the same results, they are equivalent. Quibbling over which may be right or wrong misses the whole point. There is no need to interpret anything. All these interpretations, be they Copenhagen, or Many Worlds, or Bohmian, commit the same, basic mistake: They ascribe reality to things which are not measurable, they want to explain where there is really nothing left to explain. There is nothing more than predicting all the outcomes of all measurements. And that is where all these interpretations falter, and give in.

All "interpretations" of QM must necessarily predict the same outcomes for experiments. Otherwise, they would have been shown to be false. But as they do not make different predictions, it is moot to discuss them. They are the same.

Intuition is a not a good master once you begin to seriously deal with phyiscs. Rigor is.