All of Edith's Comments + Replies

Ah, nice catch - I see your point now, quite interesting. Now I'm curious whether this bomb-testing setup makes trouble for other quantum foundation frameworks too...? As for QD, I think we could make it work - here is a first attempt, let me know what you think (honestly, I'm just using decoherence here, nothing else): If the bomb is 'live', then the two paths will quickly entangle many degree of freedom of the environment, and so you can't get reproducible records that involve interference between the two branches. If the bomb is "dud", then the two paths remain contained to the system, and can interfere before making copies of the measurement outcomes.  Honestly, I have a bit of trouble arguing about quantum foundation approaches since they all boil down to the same empirical prediction (sort of by definition), most are inherently not falsifiable - so ultimately feel like a personal preference of what argumentation you find convincing. I just meant that good-old scientific method is what we used to prove classical mechanics, statistical mechanics, and QM. In either case, it's a matter of anyone repeating the experiment getting the same outcome - whether this outcome is "ball rolls down" or "ball rolls down 20% of the time".  I'm trying to see if we can say something in cases where no outcome is quite reproducible - probabilistic outcome or otherwise. Knightian uncertainty is one way this could happen. Another is cases where we may be able to say something more than "I don't know, so it's 50-50", but where that's the only truly reproducible statement. 

Thanks for your comments! I'm having a bit of trouble clearly seeing your core points here - so forgive me if I misinterpret, or address something that wasn't core to your argument. To the first part, I feel like we need to clearly separate QM itself (Copenhagen), different Quantum Foundation theories, and Quantum Darwinism specifically.  What I was saying is specifically about how Quantum Darwinism views things (in my understanding) - and since interpretations of QM are trying to be more fundamental than QM itself (since QM should be derived from them), we can't use QM arguments here. So QD says that (alive, dead) is the complete list because of consensus (i.e., in this view, there isn't anything more fundamental than consensus).  I don't think I agree with (or don't understand what you mean by) "including the superposition of dead and alive leads to actual physical consequences" - bomb-testing result is consequence of standard QM, so it doesn't prove anything "new."   To the second part, I implicitly meant that reproducibility could mean wither deterministic (reproducibility of a specific outcome), or statistical (reproducibility of a probability of an outcome over many realizations) - I don't really see those two as fundamentally different. In either case, we think of objective truth (whether probabilistic or deterministic) as something derived from reproducible - so, for example, excluding Knightian uncertainty.