[Totient]

I think this article is side-stepping an important philosophical point as to what randomness is.

Suppose we lived in a deterministic universe (e.g. one that actually ran on Newtonian mechanics and classic electromagnetism).

If you're of a mildly Bayesian persuasion, you 'believe' in randomness - even in a deterministic universe - because probability represents your knowledge. Sure, all the rules for the universe's evolution over time are deterministic, but you don't know the initial conditions, so you consider some probability distribution over initial conditions. Thus, the results of future events are 'random.'

The counterargument might go something along the lines of "that's not really random the way quantum mechanics is, because Bell's inequality demands violating either hidden-variables or locality and violating locality is worse. Without local variables, you can't meaningfully talk about having a 'underlying' deterministic universe."

Except you (sort of can). Bell's inequality implies that we can't have a theory with local laws of physics for single universe. But we can have a theory with local laws of physics for a multiverse which is the approach many-worlds takes.