Uhh? Duh! — tom

Exactly.

So, in order to single out one of those (philosophical) theories from all the rest and make it valid, you'd need to perform testing and falsifying that it passes. Philosophy goes nowhere without science.

In a nut shell: scientific claims must necessarily relate to the physical (or actual) world we live in, in such a way that it is somehow conceivably observable, or else it's predictions can never be tested, and therefore can never be falsified, which would render us unable to determine if it is a predictively reliable belief or not — VagabondSpectre

I suppose that means that various interpretations of quantum mechanics are not scientific?

I suppose that means that various interpretations of quantum mechanics are not scientific? — Michael

Most interpretations of quantum mechanics are in fact alternative theories, which in the end make different predictions. Some interpretations however can be dismissed as emblematic of bad philosophy, e.g. Copenhagen and "Shut Up and Calculate".

What's the difference between a philosophical belief and a scientific belief? — Martian From Venus

Science is a method within a theory of knowledge.
Science relies upon empirical evidence and/or logic to support claims of knowledge.

Essentially belief is irrelevant to science, it is about what evidence you can demonstrate and whether or not the logic you use is valid.

If a hypothesis cannot generate or be used to assist in generating any testable predictions then we are unable to test it by observing the outcomes of experiments; it cannot be falsified.

So if we have a given hypothesis which cannot generate any predictions whatsoever, it will never be scientifically reinforced through experimental confirmation. If a hypothesis does generate predictions, but we are (as yet) unable to test those predictions (due to being unable to control the required experiment, or to observe the results), then at that time a given hypothesis likewise cannot be considered scientifically reinforced/accurate/valid/confirmed/tested/etc...

Keep in mind that when experimental results agree with our modeled predictions we do not instantly take the predictive hypothesis to be "confirmed", instead we ascribe it a degree of confidence; confidence in predictive power; reliable predictive power. The more accurately and reliably a model can make successful predictions, the more confidence points we give it. When a hypothetical model results in incorrect predictions, we do not instantly throw it out (we check to make sure we conducted the experiment and recorded the results correctly) and then we try to modify the model (especially if the model has some predictive power to begin with) but if a model continues to generate inaccurate predictions, then we consider it falsified.

So what does this mean for some of the more esoteric hypothetical models of the quantum world?

Well, let's start with the double slit test; the wave-life function of quantum particles enable them to interact with possible versions of themselves when unobserved (forgive me Einstein, I know not what I say!). Even though we're not yet where we want to be with our grasp of how or why this happens, we still are able to set up meticulously regulated experiments in order to see if this model holds true (the wave pattern it creates after interacting with itself). So long as this model remains unfalsified through experimentation and so long as it's predictions remain true, it is "scientific" simply by virtue of being the most predictively reliable, and as yet unfalsified, explanation we have (remember the changing or relative "standards" of science and it's various fields). The model itself is going to be modified (perhaps greatly) in the future in order to expand it's predictive power and then to refine the reliability and accuracy of those predictions, but for now it's a part of one of the best quantum models we have. It might turn out to be totally wrong one day, sure, but that's always a risk inherent in science. There's no ultimate certainty, only degrees of confidence in reliability; science is a wager.

When it comes to some other hypotheses, like the many worlds interpretation of QM phenomenon, we are not yet and may never be able to use it to make any predictions or run any experiments to see if it holds true with what is observable. That's why the wave function description of quantum mechanics is said to be scientific while the MWI and many other hypotheses are not; experiments, predictions, and observable results..

When it comes to some other hypotheses, like the many worlds interpretation of QM phenomenon, we are not yet and may never be able to use it to make any predictions or run any experiments to see if it holds true with what is observable. — VagabondSpectre

Except that it is testable:

https://arxiv.org/pdf/1508.02048v3.pdf