Summary of “A quantum experiment suggests there’s no such thing as objective reality”

Back in 1961, the Nobel Prize-winning physicist Eugene Wigner outlined a thought experiment that demonstrated one of the lesser-known paradoxes of quantum mechanics.
The experiment shows how the strange nature of the universe allows two observers-say, Wigner and Wigner’s friend-to experience different realities.
Physicists have used the “Wigner’s Friend” thought experiment to explore the nature of measurement and to argue over whether objective facts can exist.
That’s provided some entertaining fodder for after-dinner conversation, but Wigner’s thought experiment has never been more than that-just a thought experiment.
Last year physicists noticed that recent advances in quantum technologies have made it possible to reproduce the Wigner’s Friend test in a real experiment.
Their conclusion is that Wigner was correct-these realities can be made irreconcilable so that it is impossible to agree on objective facts about an experiment.
Wigner has no information about his friend’s measurement and so is forced to assume that the photon and the measurement of it are in a superposition of all possible outcomes of the experiment.
In other words, the experiment suggests that one or more of the assumptions-the idea that there is a reality we can agree on, the idea that we have freedom of choice, or the idea of locality-must be wrong.

The orginal article.