Is your quote supposed to imply something on its own? Because as far as I can tell, it's merely explaining the position I'm arguing - Gisin hasn't commented on its viability in that section.
If experiments can't ever be finished, then how can they be done?
But no experiment is ever done by someone outside of the universe.
Every experiment entails a split history. Gisin explains why he is so "dismissive with this view" for this reason: empirical methods applied to build useful models (i.e., we can predict the behavior of systems using the model) in physics as with all sciences and the fact that the many-worlds view has none: "I do not see any explanatory power in the many worlds view: it seems to be made just to prevent one from asking (possibly provocative) questions.
Moreover, it has built into it the impossibility of any test: all its predictions are identical to those of quantum theory. For me, it looks like a “cushion for laziness” (
un coussin de paresse in French)."
Basically, the many-worlds explanations take the results of the assumption that similar systems prepared in this universe don't cause the splitting and therefore can be used to develop the formalisms we require in every single experiment, but throw out the assumption while leaving the results. Yet as there is no meaning to the results, all the many-worlds theories have accomplished is to take a developed model, remove how it was developed and therefore any validity to it, but treat it as if it were independently validated even though it is not, while at the same time providing nothing to offer except a convenient way of avoiding dealing with a measurement process that is difficult to explain. The formalisms were developed under the assumption that this splitting didn't occur. Imagine trying to determine the probability of obtaining an ace from a deck of cards when you don't know how decks of cards work; after repeatedly drawing from the deck and shuffling, you can reconstruct the number of suits and types of cards, all under the assumption that you are working with the same deck. That's how we obtained the quantum formalisms we use: assuming that when we pick from the deck (observe), we haven't created two new decks, and only one of which we can observe such that we can know nothing about the result of the draws from the other deck. The many-worlds theories takes the statistically developed formalisms which require the non-splitting, use these formalism but claim the splitting occurs, yet offer no reason for the formalism or evidence that the splitting occurs. The theories just avoid having to answer the measurement problem by saying there is no measurement and then refusing to offer any explanation for why the formalisms work or how the theory explains anything.
Things still interact inside the gigantic wavefunction, so any beings inside that structure can see "measurements" happen
Then there is no reason for the giant wavefunction. It's completely irrelevant and superfluous.
They're just not measurements in the sense that they do not collapse the wave.
They aren't measurements of anything. That's the point.
Hence, they conclude: quantum measurements are never finished, everything gets into an enormously complex state of superposition.
We don't measure, we just split universes and pretend that somehow we can relate the system transcribed to observables obtained under the assumption that the system doesn't split to talk about the states of systems we never actually really measured. And as for he "collapse" language- while is still around, it is largely replaced by coherence and decoherence, because the idealized isolation of early QM isn't held onto anymore.
So because we stick in kludges to make the calculations easier, that means the full-blown non-kludged theory is wrong somehow?
It doesn't make any calculations easier. It steals the calculations, erases how they were obtained, renders useless measurements in any way apart from vague notions of ongoing measurements which provide a very clear reason why measurements of a single system can result in system states that seem to describe different systems, but offer no predictive power and cannot explain how the observables were obtained to begin with (as this mathematical procedure assumes that similar systems can be statistically related because they do not split).
We still observe things in the everything's-a-WF model, it just shows up differently. The answer is now not "The wave collapses when you open the box and the cat is definitely alive or dead," it's, "The cat is both alive and dead, and your brain just got entangled with it."
That's the many-minds interpretation. It's the "observation creates reality" view of QM. And like the many-worlds interpretation, all it does is explain a measurement/observation without evidence and by removing what allows us to experiment at all.
Measurements only return single answers.
We can perform multiple measurements at the same time, and as "answers" can have multiple values, even if the above were true it wouldn't matter.
Doing lots of observations and then working backwards and realizing that the particle had to be in two states at once isn't the same thing as detecting it in two states at once.
Good thing we don't do that.
The observer does observe classical-esque results because the observer is superpositioned.
The -esque part shouldn't be there. There's no reason for it.
Once that superposition happens, the branches evolve indepdently
And thus we have no reason to assume that the methods we developed to relate measurements to anything at all in terms of quantum systems (which, again, assumed no splitting) should be used. We've been handed 52 cards, performed continued experiments with drawing and shuffling from the deck until we know what the deck is composed of (4 suits of every number and the face cards), and then pretended that every time we drew from the deck it was a different deck. Which means we have 0 reason for thinking that their are 13 of each suit, or 4 suits for each number up to 10, or any face cards, because we're now claiming we've been drawing from a different deck each time.
And minds are, magically, not systems built of quantum objects?
They are. Which would mean that your neurons are constantly splitting and again leaves us with nothing usable.
That's only a consequence of treating observers as independent things that cannot be modelled. Ontologically, that's wrong.
It's a consequence of developing formalisms which assume that observations cause micro-level processes to decohere. It presents a difficult problem when it comes to explaining how these processes decohere, but the "hey, what if we pretend we aren't measuring anything!" approach is great until we need measurements.
There are only wavefunctions and observable operators in QM. Since there are no magically external observers to use the operators, what else could possibly describe the universe except one big WF?
The observable operators were statistically developed under an assumption that similar systems were the same. In other words, even if we aren't dealing with the same deck of cards, every deck that we deal with has the same type of cards. Many-world interpretations throw that out, making observable operators useless.
Because every system was part of the universe. That was the point of Laplace's clockwork - every single object within the universe had these parameters, so if you could somehow know all of them, you could predict the future precisely.
It has little at all to do with every system being part of the universe and everything to do with deterministic mechanics. Nobody thought about multiple universes such that saying a system was a part of the universe meant anything.
Also, I'm not sure where you are getting the clockwork from: "Une intelligence qui, pour un instant donné , connaîtrait toutes les forces dont la nature est animée, et la situation respective des êtres qui la composent, si d'ailleurs elle était assez vaste pour soumettre ces données à l'analyse , embrasserait dans la même formule les mouvemens des plus grands corps de l'imivers et ceux du plus léger atome : rien ne serait incertain pour elle, et l'a venir comme le passé , serait présent à ses yeux."
Une Intelligence somehow became "demon" (Maxwellian influence?), but clockwork? That I've not heard of and it sounds more like Newton.
You're trying to argue that this principle of parameters and prediction doesn't apply to a quantum universe
No, I'm waiting for you to give me something that makes this at all useful, because we don't use any universal wavefunction. All you've provided is a way to equate the universe to quantum physics without any evidence or without any ability to be used. It's a universal wavefunction that we not only can't use, but is superfluous because we do need specific wave functions for quantum systems.
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