I said: "since we can't distinguish MWI and Copenhagen." That's the exact opposite of what you're claiming I said.
You've omitted a very important part of your original sentence - the word "yet". Let's see the definition of that word:
Definition of yet
1
a : in addition : besides gives yet another reason
b : even 2c a yet higher speed
c : on top of everything else : no less
had wells going dry. Between two large lakes, yet — J. H. Buzard
2
a (1) : up to now : so far hasn't done much yet —often used to imply the negative of a following infinitive have yet to win a game (2) : at this or that time : so soon as now not time to go yet
b : continuously up to the present or a specified time : still is yet a new country
c : at a future time : eventually may yet see the light
Definition (2, c) seems to be the most appropriate here. This implies that you firmly believe that there is a point at a future where the Copenhagen's Interpretation and the Many-Worlds Interpretation would be distinguished by an experiment. Since laws of physics don't change over time, this means that you believe that Copenhagen and MWI are not just interpretations at any point of time, including the present.
"Everything but QM is deterministic!"
"No, that's wrong. QM is probabilistic."
"Everything but QM" only
looks deterministic, because the probabilities involved are usually too small for detection, but that doesn't change the fact that they are, actually, probabilistic. Anything that interacts with a probabilistic thing inevitably becomes probabilistic itself, and there's nothing physical that doesn't come into contact with QM.
You're not looking at it the right way. Configuration space and complex amplitudes and whatnot, those are the fundamental thing of reality. And they act deterministically, not probabilistically. The only probabilistic part is the Born rule.
I don't think it's really fair to say "the only probabilistic part", when almost any interaction between two objects in QM involves it happening.
That's cheating. The rest of physics takes, perhaps, a probabilistic input, but they act deterministically on that input.
As abovementioned, that's an illusion.
And the other worlds can observe themselves. The analogy holds.
Except for the part where you've claimed that Copenhagen's interpretation makes the ship disappear, but sure, whatever.
But why would some parts of the wave-function go away just because they've been looked at?
They don't. First, it's interaction and not "looked at", second, if I may so ask a counter-question, why does gravity attract things together and not, say, repel them? The only possible answer here is, ultimately, "that's how universe works". All interpretations are simply artificial explanations we make in order to try and make "logical" sense out of what we observe, and to me, an interpretation that doesn't require to store an infinite number of fundamentally unobservable states of the world, even if it involves axiomatically introducing probability into the system, is much simpler than the one that does.
But as long as they are just interpretations, they're all technically equally valid, nullifying my point that you can't calculate stuff with it. I guess I was wrong there.
Of course, since you've made that fateful "yet" and claimed that it was "better", that means that you believe that it's more than just an interpretation, which is probably the part which I was against at in this argument.
No, you're just saying "it's random". That's a statistical law, not a mechanism.
What do you mean by "mechanism", then? No, really, what is a mechanism? Is it supposed to be something inherently deterministic?
You're misrepresenting me. You're claiming that I said that there was an experimental difference between the two, but I actually said that there wasn't an experimental difference.
If you've meant that, then you've not managed to convey it properly.
I mean, with spin, it's always discrete, but with, for example, position of a particle in a one-dimensional world where the potential field's energy is zero in the range of [-1,1] and equals U outside of it, it's discrete if it doesn't have sufficient energy to escape to infinity (i.e. if its kinetic energy is lower than U), and continuous otherwise. Same with wave-function - without interactions, it continues to propagate and expand in a continuous manner, but with interactions, it discretely collapses into a different form.
I'm a little confused here.
Oh right, sorry, I've seriously confused some things here. I meant the possible energies for an electron in a hydrogen-like atom. The energy spectre is discrete where the total energy of the system is below zero, and continuous when it's above zero.
Something like that. It's both discrete and continuous at the same time.
You see the wave-function as a probability-determiner for the basic stuff of the universe, I see the wave-function as the basic stuff of the universe.
I guess you could do that, but then you'd have to work with a wave-function in an infinitely-large state space defined with an infinitely-long number of arguments. Starting from a limited quantity of particles and then going to wave-functions as determined by their parameters and, when necessary, their interactions, seems much simpler to me.
But if that's what is simpler for you, then sure. Just don't claim that it's objectively better.