But is it science?: Theoretical physicists who say the multiverse exists set a dangerous precedent: science based on zero empirical evidence (Jim Baggott, 10/07/19, Aeon)
There is no agreed criterion to distinguish science from pseudoscience, or just plain ordinary bullshit, opening the door to all manner of metaphysics masquerading as science. This is ‘post-empirical’ science, where truth no longer matters, and it is potentially very dangerous.
It’s not difficult to find recent examples. On 8 June 2019, the front cover of New Scientist magazine boldly declared that we’re ‘Inside the Mirrorverse’. Its editors bid us ‘Welcome to the parallel reality that’s hiding in plain sight’.
How you react to such headlines likely depends on your familiarity not only with aspects of modern physics, but also with the sensationalist tendencies of much of the popular-science media. Needless to say, the feature in question is rather less sensational than its headline suggests. It’s about the puzzling difference in the average time that subatomic particles called neutrons will freely undergo radioactive decay, depending on the experimental technique used to measure this – a story unlikely to pique the interests of more than a handful of New Scientist’s readers.
But, as so often happens these days, a few physicists have suggested that this is a problem with ‘a very natural explanation’. They claim that the neutrons are actually flitting between parallel universes. They admit that the chances of proving this are ‘low’, or even ‘zero’, but it doesn’t really matter. When it comes to grabbing attention, inviting that all-important click, or purchase, speculative metaphysics wins hands down.
It would be easy to lay the blame for this at the feet of science journalists or popular-science writers. But it seems that the scientists themselves (and their PR departments) are equally culpable. The New Scientist feature is concerned with the work of Leah Broussard at the US Department of Energy’s Oak Ridge National Laboratory. As far as I can tell, Broussard is engaged in some perfectly respectable experimental research on the properties of neutrons. But she betrays the nature of the game that’s being played when she says: ‘Theorists are very good at evading the traps that experimentalists leave for them. You’ll always find someone who’s happy to keep the idea alive.’
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.