Below is my answer to a different question, but I think most of the points I make there are relevant here as well. My answer can be summarised as "there might not be an underlying theory, but then again there might, and if we don't look for it then we'll never find it." Not everybody has to participate in such a search, but it would be foolish not to take the chance of having a few people working on it.

My answer to the other question follows:

Edwin Jaynes argued that Niels Bohr's original version of the copenhagen interpretation was exactly that: a theory that only makes epistemological statements and refuses to say anything about an ontological world. However (according to Jaynes) most people didn't really understand what Bohr was saying, so what we normally think of as the Copenhagen interpretation is a misinterpretation of the interpretation, in which Bohr's epistemological statements become ontological facts about the world.

In any case, it is certainly possible to interpret the formalism of quantum mechanics that way. In fact I would say that it's the only reasonable way to interpret the mathematical formalism. Quantum mechanics is basically a formalism for predicting the outcomes of experiments. Everything you calculate is an operationally defined probability of the form "if you do this experiment, these are the outcomes that can occur". However, the mathematical formalism has nothing to say about any ontological process that would cause those particular outcomes to occur with those particular probabilities. This is exactly why there is so much room for "interpretation" of the equations.

However, I would argue (along with Jaynes) that this doesn't mean we should throw ontological thinking out the window just yet. It might be that, for some reason, we live in a Universe that (in some yet-to-be-clearly-stated sense) fundamentally has no ontological reality. But then again, there *might* be an underlying ontological reality, and if there is then knowing about it would lead to new fundamental physics. We know from Bell's theorem and similar results that if this underlying reality does exist then it must have certain (arguably counterintuitive) properties, but its existence cannot be ruled out entirely at this point. Depending on your philosophical outlook you might consider the existence of such a thing to be more or less unlikely, but you'd have to be pretty hard-line to discount it entirely. If we don't look for it we'll never find it, so it seems wise to have at least a few smart people thinking about the possibility.

As an analogy, the Lorentz transforms were already worked out (by Lorentz) before Einstein, but their interpretation was unclear. We could just have stopped there - we had the equations after all, and so why not remain content to interpret them operationally? But Einstein's ontological interpretation led not only to a more elegant way of understanding the mathematics but also to matter-energy equivalence and ultimately to general relativity. It would be hard to argue in that case that the search for an ontological interpretation was a useless concept leading down a philosophical rabbit hole to nowhere.

It is my hope (not belief, just hope) that one day something similar will be done for quantum mechanics, enabling us to see, if not *the* underlying ontological reality then at least one level further down. This requires more than just an interpretation of the equations - it requires a new theory that makes testable predictions, while also reducing to quantum mechanics in some appropriate limiting case. It is my suspicion that many of the biggest unsolved issues in physics (and in particular the unification of quantum mechanics with general relativity) will not be fully resolved unless we can accomplish this.

This post imported from StackExchange Physics at 2014-05-12 15:02 (UCT), posted by SE-user Nathaniel