> I don't think it's even been settled that quantum mechanics are truly, for sure probabilistic.
Since you can never prove or disprove the existence of "God" or some other hidden global variable deterministically moving the universe, yes, nothing can ever be settled. Scientists don't find that line of reasoning particularly interesting or compelling to dwell on.
You're right, I didn't mean to add so much emphasis on 'knowing'. I meant settled in the sense of 'settled science', or being as reasonably sure as we can--barring any flying spaghetti monsters. Far from being uninteresting to scientists, I'd argue that this question of whether quantum mechanics is truly probabilistic or hides deeper deterministic mechanisms is one of the most profound topics in physics
Since you can never prove or disprove the existence of "God" or some other hidden global variable deterministically moving the universe, yes, nothing can ever be settled. Scientists don't find that line of reasoning particularly interesting or compelling to dwell on.