They aren't paradoxes of quantum mechanics.
They are a paradox between how we intuitively expect the world to work and reality. Our intuition is wrong.
They are a paradox between how we intuitively expect the world to work and reality. Our intuition is wrong.
That very common view is a paradox because different observers can have different notions of "measurement" and they are incompatible.
plus, our intuition is just as much a part of reality as your "reality".
"Proof by contradiction" is a proof that the opposite is true, and is constructed so that if the thing you try to disprove would be true, you could create a paradox/contradiction.
that is the critique at hand, is it not? my understanding of the paradoxes in quantum mechanics stem from things, like measurement, being unspecified or at least being specified or interpreted without consensus.
Also the emergence of an apparently paradox is a great heuristic that raises the question of whether our intuition and understanding is wrong or correct.
> Quantum mechanics will work the way it does regardless of what your intuition on how it should work thinks.
i didn't say otherwise, although i think what you've stated is debatable.
So the real problem isn't in quantum mechanics, it's in what the hell consciousness is and why it works the way it does.
However, note that you can have observations performed by a computer which e.g. counts events, and the counter will exist in all "worlds" (branches of the universal wave function, really), while each incarnation of it only "perceives" one such "world". So the physics works just fine even while we don't fully understand consciousness.
I never see a definition of measurement, or observation.
If there are many worlds, how is it decided which one we are in?
MWI is scientifically equivalent to collapse, it's just imagined as a branching instead of a selection among alternatives.
So MWI goes from "That's random and we don't know why" to "That's random, we don't know why, but now we've added a universe too, although we can't prove it exists."
Something about this doesn't seem entirely convincing.
My layman's understanding was that MWI doesn't postulate multiple universes. Rather, it posits that all particles are always in superpositions of states. What looks like a collapse to a single state is actually the particles under observation getting entangled with the particles that compose the observer: so, in the case of the double-slit experiment, you have a combined particle-observer system in a superposition of the states (particle goes through left slit / observer sees left detector activated) and (particle goes through right slit / observer sees right detector activated). Nothing has actually changed other than that entanglement: nothing is created or appears, certainly not an entire new universe.
ETA: like I say, I'm a layman, so I'd welcome any correction.
Unsurprisingly, these experiments with "partial collapse" produce exactly the predicted results of QM. And are exactly in line with, "And if the system gets more complicated still, collapse becomes irreversible." (Where "more complicated still" is very simple compared to ordinary macroscopic objects.)
The Many-Worlds interpretation is nice and fun to talk about, but it hasn't done any heavy lifting in terms of reducing the number of postulates required to describe quantum mechanics.
The two most promising ideas (IMO) are the idea that the "wave function collapse" is a non-physical event describing a change in our knowledge, the quantum informatics approach as per Philip Ball's recent RI lecture,[1] and the "Relational" interpretation[2] which observes that a measurement always entangles the measuring system with the measured system, and is best treated as such - i.e. as an entanglement relationship; though it seems that this leads to an "entanglements all the way down" view in which these relationships are the ultimate physical reality, rather than the conventional picture of the relationships being secondary to the things which are so related.
The "measurement as entanglement" view is, I know, notably supported by at least one HN poster[3], who I hope will be on hand to correct my no-doubt erroneous rendition :)
1: https://www.youtube.com/watch?v=q7v5NtV8v6I
2: https://en.wikipedia.org/wiki/Relational_quantum_mechanics
No.
For a start, there is no evidence that the ones you are calling "not quite so actual" are any less actual than the one we share an experience of.
Continuing on, the interpretation does not attempt to explain the phenomena of perceived consciousness. That is as much out of its remit as abiogenesis is out of the remit of Darwin's theory of evolution. Those problems are different in kind, much harder, and have to be addressed by very different theories.
Everett addressed a precise problem. That problem is explaining why, to the extent that QM describes an observer, the act of observation must turn that observer into a superposition of observers. Each of which has observed an apparent collapse, and none of which can interact further in any meaningful way.
Well, there is evidence of the one I'm calling "actual" - if it's evidence you want, there's no evidence at all of the "not so actual" ones - citing the MW interpretation as evidence of these is purely circular.
Regards not explaining perceived consciousness.. If MW is shunting off questions of actuality into something to be resolved by a theory of consciousness isn't it leaving behind centuries of consensus belief in the objective observer-independent existence of a physical world ontologically prior to consciousness?
The existence of such a proof would provide a genuine scientific basis for not continuing to address the problem.
Without that proof, the problem remains open.
There is a list of axioms of quantum mechanics, Copenhagen and MWI disagree only on how you get to them. (And also on their conceptual interpretation). That's why they're called interpretations of quantum mechanics, not theories of quantum mechanics.