[ExI] Is the wave function real?

[Stuart LaForge]

Jason Resch wrote:

<The wave function is a standard assumption of all QM
theories/interpretations that accurately describes the evolution of any
isolated system. The universal wave function just treats the entire
universe as an isolated system, and applies the regular rules of QM to
determine how it evolves.>

When I took college chemistry, I was taught the Copenhagen "shut up and
calculate" interpretation of QM. This was back in 90's. One of the things
I noticed was my professors were hesitant to discuss anything to do with
the implications QM might have for the nature of reality.

Because of this, I tended to regard QM as an accurate-as-possible
epistemic model of the behavior of entities on the lower limit of what we
can, with sensitive instrumentation, measure. I suspected that the wave
function itself was a statistical compromise for hidden variables that we
just didn't have the ability to detect.

Over the years, I have resisted thinking of the wave function as a real
entity. To my mind, it simply organized and quantified our ignorance about
the system and its degrees of freedom sort of like Boltzmann entropy. In
my opinion, to think otherwise would smack of platonism and a dualistic
world view.

The reason I bring this up is that MWI posits an ontologically real
Universal Wave Function that I capitalize because, like the Internet, it
is unique. It represents the wave function of every wave-particle in the
universe, including those that comprise the observer, entangled into a
giant wave function with a possibly infinite number of terms.

Infinity sitting somewhere out there in Hilbert space, doling out entire
universes to observers who roll the quantum dice. I thought it was a bit
much to swallow. On the flip side, I have always admired MWI for its
deterministic nature, the fact that it is a better fit with GR,
decoherence, etc.

So this was all until just yesterday when I found this paper:

http://www.nature.com/nphys/journal/v11/n3/full/nphys3233.html

For those of you trapped behind a paywall, here is the arxive version:

https://arxiv.org/pdf/1412.6213v2.pdf

So now apparently we have empirical evidence suggesting the wave function
really is real and published in nature, no less. So that rules out about
one third of the extant interpretations of QM out there, including
Copenhagen.

Stuart LaForge