In other words, claiming other universes exist but we can’t observe or detect them is like saying I always dream in Latin: it’s something that’s impossible to prove or disprove, leaving it beyond science and of little practical use.
Smolin isn’t averse to the idea of other universes. He’s even developed a theory of “cosmological natural selection”, where universes give rise to offspring universes with slightly different properties which may make them more or less likely to in turn spawn further universes. But this is different from the popular multiverse idea of all these universes existing alongside each other.
So what about these findings from the Planck Observatory, described by – of all things – Catholic Online as the “first solid proof of other universes beyond ours”? There’s no mention of the multiverse in the latest official European Space Agency data or analysis from Planck. The inference comes from Laura Mersini-Houghton, a theoretical physicist at the University of North Carolina at Chapel Hill, who I met when she spoke recently at a philosophy and music festival in Wales. For years, she’s argued that anomalies in Planck’s map of cosmic microwave background radiation – the aftermath of the Big Bang – can be explained by another universe pulling on our own. Perhaps they can, and some of Planck’s findings do fit strikingly with her predictions. And perhaps in another reality that would be all that’s needed to convince the scientific community that ours is not the only universe. But in this one, for a theory like that to be taken as “solid proof”… that would be, well, unparalleled.