It is generally believed that the early universe widely inflated. So, reporting on a recent article submitted to Journal of Cosmology and Astroparticle Physics, Stony Brook astrophysicist Paul Sutter points out:
First off, they found that eternal inflation wasn’t nearly as common as originally thought. Their explanation for why cosmologists had thought eternal inflation was generic was because those earlier cosmologists had studied only a limited set of models. They found that many viable inflation models (“viable” here means they didn’t obviously contradict observations) didn’t lead to an eternally inflating scenario.Paul Sutter, “How real is the multiverse?” at Space.com (December 16, 2021)
Cosmologists line up on both sides:
Prominent proponents of the multiverse have included well-known cosmologists such as Max Tegmark and Alexander Vilenkin, Brian Greene and Neil Turok, Alan Guth and Stephen Hawking, as discussed in online science magazines. But opponents include theoretical physicist Sabine Hossenfelder(“Why the multiverse is religion, not science”), cosmologist Paul Davies (“it also leads to a fake universe with fake physics”, which undermines arguments from physics) and cosmologist George Ellis(“beyond the domain of science”). Well-known science writer John Horgan considers the idea “bad for science” and mathematician Peter Woit thinks that it “has left conventional science completely behind.”
Maybe it is much easier for us to imagine an infinite number of ourselves than for nature to make it happen. Works the same with money…
You may also wish to read: In an infinity of universes, countless ones are run by cats… Daniel Díaz notes that most of the talk about the multiverse started to appear once it was realized that there was fine-tuning in nature. Robert J. Marks points out that even 10 to the 1000th power of universes would only permit 3,322 different paths. Infinity is required but unprovable.