Yeeeeeah, but. There’s always a ‘but’, isn’t there?
Up until last year, the proposition of a multiverse was simply that: a proposition. But then a few physicists decided to go meet Wigner’s Friend:
Last year, however, 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.
The article was obviously “dumbed down” for non-scientists like myself (here’s the paper in all its full-blown arcana), but it does seem to give the multiverse argument a bit of experimental veracity. In fact, their work goes so far as to suggest that there is no such thing as “objective reality”, that it is impossible for two observers to see the exact same result.
In other words, there now seems to be more experimental evidence for a multiverse than against it.
But if they’re right, reality really will be like opinions: everybody’s got one, they’re all at least a little different, and they all stink.