I have read that Nobel prize winner physicist Eugene Paul Wigner rejected Many Worlds Hypothesis for being unfalsifiable.
But I have seen a lot of papers and books that seem to contradict this: Specifically, Wigner's Friend experiment yields the existence of multiple realities and that Wigner in fact believed that multiple incompatible realities exist simultaneously:
Finally, Wigner and his friend can meet and discuss what they will get if they measure the qubit in the computational basis. Believing in Many-Worlds, Wigner says that they will see the result 0 with certainty.
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. In other words, it ought to be possible to create different realities and compare them in the lab to find out whether they can be reconciled. And today, Massimiliano Proietti at Heriot-Watt University in Edinburgh and a few colleagues say they have performed this experiment for the first time: they have created different realities and compared them. 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.
Besides I found a question in Quora that, although it does not cite any references, it seems to indicate that Wigner proposed some kind of version of Many Worlds Interpretation.
So, what is happening here? Did Wigner believe or propose that multiple alternate realities exist?