Originally Posted by dr wu23
The existence of an alternative reality/universe proves by definition that the many worlds theory is true so how could anyone in one of the alternate worlds prove it not true?
Have you read the Superman comics? One of the villians is Bizarro, an evil version of Supernman from a universe that is opposite to Superman's in every way. That's not something that would be impossible in real life and there just might be a polarity between one universe and another as one of the anything can happen happening things that happen. So, the day one physicist proves the existence of parallel worlds in one universe, his Bizzaro counterpart would prove the nonexistence of parallel universes. It all comes down to perception and what the data the physicists are receiving tells them is a law of their home universes' physics. Reality is the sum of what each universe's objective reality is perceived to be.
A Bizarro version of every universe is one where wave function collapsed in the opposite way every time, which is one of the outcomes of every quantum equation. Polarity of universes is not an impossibility.