Somewhat related to the previous post, I just saw this video from Matt O’Dowd discussing why the block universe is such a compelling concept.
The second video in the series discusses the effect quantum mechanics might have on this concept. It reminds me why cosmologists seem to be more comfortable with the Many Worlds Interpretation rather than the orthodox Copenhagen one. The idea of uncollapsed wave functions in the future is complicated by the relativity of simultaneity.
What’s interesting about this is that, while the Many Worlds Interpretation definitely leads to an overall block universe, or block multiverse if you prefer, it still has each of us living in an emergent classical world with the experience of randomness in it. So in the block universe, not only does all the past, present, and future have an eternal existence, but every possible variation of that past, present, and future does as well.
Whether you find that comforting, alarming, or merely interesting, it seems to neatly split the difference between a rigid universe and one with an evolving future.
There are plenty of other interpretations of quantum mechanics out there, but it’s not clear that any of them fit quite as nicely with overall cosmology as Many Worlds. Of course, many, like Copenhagen, are anti-real interpretations, in that rather than attempting to describe reality, they merely describe our interactions with the quantum realm, and so aren’t necessarily expected to reconcile with cosmological models. The problem is they provide little help with cosmological questions.
Anyway, the rest of this series looks like it’s going to be interesting.