There is no end to the practical jokes we can pull on the poor electron! But with a weary smile, it always shows that the joke is on us. The electron appears to be a strange hybrid of a wave and a particle that’s neither here and there nor here or there. Like a well-trained actor, it plays the role it’s been called to perform. It’s as though it has resolved to prove the famous Bishop Berkeley maxim “to be is to be perceived.”

Is nature really this weird? Or is this apparent weirdness just a reflection of our imperfect knowledge of nature?

The answer depends on how you interpret the equations of quantum mechanics, the mathematical theory that has been developed to describe the interactions of elementary particles. The success of this theory is unparalleled: Its predictions, no matter how “spooky,” have been observed and verified with stunning precision. It has also been the basis of remarkable technological advances. So it is a powerful tool. But is it also a picture of reality?

Here, one of the biggest issues is the interpretation of the so-called wave function, which describes the state of a quantum system. For an individual particle like an electron, for example, the wave function provides information about the probabilities that the particle can be observed at particular locations, as well as the probabilities of the results of other measurements of the particle that you can make, such as measuring its momentum.

Does the wave function directly correspond to an objective, observer-independent physical reality, or does it simply represent an observer’s partial knowledge of it?

If the wave function is merely knowledge-based, then you can explain away odd quantum phenomena by saying that things appear to us this way only because our knowledge of the real state of affairs is insufficient. But the new paper in Nature Physics gives strong indications (as a result of experiments using beams of specially prepared photons to test certain statistical properties of quantum measurements) that this is not the case. If there is an objective reality at all, the paper demonstrates, then the wave function is in fact reality-based.

What this research implies is that we are not just hearing different “stories” about the electron, one of which may be true. Rather, there is one true story, but it has many facets, seemingly in contradiction, just like in “Rashomon.” There is really no escape from the mysterious — some might say, mystical — nature of the quantum world.