Theoretical astrophysicist Ethan Siegel may be sure that it exists but perhaps that’s just a private revelation:
The ‘mirrorverse’ is just one more in a long line of so-called multiverse theories. These theories are based on the notion that our Universe is not unique, that there exists a large number of other universes that somehow sit alongside or parallel to our own. For example, in the so-called Many-Worlds interpretation of quantum mechanics, there are universes containing our parallel selves, identical to us but for their different experiences of quantum physics. These theories are attractive to some few theoretical physicists and philosophers, but there is absolutely no empirical evidence for them. And, as it seems we can’t ever experience these other universes, there will never be any evidence for them. As Broussard explained, these theories are sufficiently slippery to duck any kind of challenge that experimentalists might try to throw at them, and there’s always someone happy to keep the idea alive.
Is this really science? The answer depends on what you think society needs from science. In our post-truth age of casual lies, fake news and alternative facts, society is under extraordinary pressure from those pushing potentially dangerous antiscientific propaganda – ranging from climate-change denial to the anti-vaxxer movement to homeopathic medicines. I, for one, prefer a science that is rational and based on evidence, a science that is concerned with theories and empirical facts, a science that promotes the search for truth, no matter how transient or contingent. I prefer a science that does not readily admit theories so vague and slippery that empirical tests are either impossible or they mean absolutely nothing at all.
Jim Baggott, “But is it science?” at Aeon
He doesn’t like ID either but he also doesn’t appear to understand it:
And, no matter how much we might want to believe that God designed all life on Earth, we must accept that intelligent design makes no testable predictions of its own. It is simply a conceptual alternative to evolution as the cause of life’s incredible complexity. Intelligent design cannot be falsified, just as nobody can prove the existence or non-existence of a philosopher’s metaphysical God, or a God of religion that ‘moves in mysterious ways’. Intelligent design is not science: as a theory, it is simply overwhelmed by its metaphysical content.
Jim Baggott, “But is it science?” at Aeon
Intelligent design could certainly be falsified if it could be shown that complex, specified information arises all the time naturally from nothing. And no one has shown that. The presence of vast amounts of information in life forms that exceed random walks is evidence, provided one is willing to look at it.
Incidentally, anyone familiar with Darwinism (popularly called “evolution”) will know that it cannot be falsified. But that’s not a barrier to it forming part of compulsory public education.
What Baggott doesn’t seem to see is that the multiverse and Darwinism are accepted for ideological reasons and ID is rejected for those same reasons. None of it has anything to do with either evidence or falsification.
The multiverse fans will either proceed without evidence or make it up.
See also: Astrophysicist Ethan Siegel tells us why a multiverse must exist Siegel: “… if the theory of inflation is a good one, and the data says it is, a multiverse is all but inevitable.” Our physics color commentator Rob Sheldon writes to offer a response.