What is meant by the universe being non locally real? I'm pretty sure physics doesn't really have anything to say about realism, anti-realism, or idealism, but that hasn't stopped folks from trying. — Darkneos
You're right, it's not about the *philosophical* concept of realism, it's a physics concept.
In short, what quantum mechanical experiments, especially Bell's Test, give extremely strong evidence for, is that a classical physics type view of reality is incorrect. That's what "local realism" means.
In classical physics, for any given proerty you could measure, every object in existence has distinct values for that property - all the time, whether you're measuring it or not. Momentum, location, rotational velocity - everything has a distinct value for all measureable properties.
That's local realism, and *that* is what's not true, at least for the things we are generally inclined to think of as 'objects' at the fundamental level ie protons neutrons electrons.
Bell's Theorem demonstrates that you have to give up on at least one of locality or realism. In either words, either you have to choose to believe that causality can be non-local, faster than light, and contradict special relativity, OR you have to believe that measurable properties don't have singular distinct values when not being measured. Or both.
There is a third option, but... we don't talk about the third option.