In other words, why was it necessary for Everett to propose an hypotheses comprising the apparently radical speculation of ‘infinitely branching universes’? If it turned out not to be tenable, what would we be obliged to accept? — Wayfarer
You misrepresent what Everett proposes. To quote a paper on this point:What problem is the Many Worlds Theory of Hugh Everett a solution to? In other words, why was it necessary for Everett to propose an hypotheses comprising the apparently radical speculation of ‘infinitely branching universes’? — Wayfarer
• EVERETT POSTULATE:
All isolated systems evolve according to the Schrodinger equation d/dt |ψ> = - H|ψ>
.
Although this postulate sounds rather innocent, it has far-reaching implications:
1. Corollary 1: the entire Universe evolves according to the Schr¨odinger equation, since it is by definition an isolated system.
2. Corollary 2: there can be no definite outcome of quantum measurements (wavefunction collapse), since this would violate the Everett postulate.
• What Everett does NOT postulate:
At certain magic instances, the the world undergoes some sort of metaphysical “split” into two branches that subsequently never interact. This is not only a misrepresentation of the MWI, but also inconsistent with the Everett postulate, since the subsequent time evolution could in principle make the two terms in equation (2) interfere. According to the MWI, there is, was and always will be only one wavefunction, and only decoherence calculations, not postulates, can tell us when it is a good approximation to treat two terms as non-interacting.
In Bohmian Mechanics the wave function describes quantum potential at both slits - which are the "potential" worlds or branches that are in superposition. Zeh describes them as "empty" wave components since they don't specify where the actual particle is (this is instead specified by the Bohmian guiding function). — Andrew M
No proposal of new universes. It is not an ontological assertion. — noAxioms
You misrepresent what Everett proposes — noAxioms
The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse. Many-worlds implies that all possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In layman's terms, the hypothesis states there is a very large—perhaps infinite[2]—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes.
The quantum-mechanical "Schrödinger's cat" theorem according to the many-worlds interpretation. In this interpretation, every event is a branch point; the cat is both alive and dead, even before the box is opened, but the "alive" and "dead" cats are in different branches of the universe, both of which are equally real, but which do not interact with each other.
John Wheeler, Everett's thesis adviser, made him cut out about half the stuff in his original 137 page thesis and tone down the language so it didn't sound like he thought all those other universes were equally real when in fact he did. For example, Wheeler didn't like the word "split" and was especially uncomfortable with talk of conscious observers splitting, most seriously he made him remove the entire chapter on information and probability which today many consider the best part of the work. His long thesis was not published until 1973, if that version had been published in 1957 instead of the truncated Bowdlerized version things would have been different; plenty of people would still have disagreed but he would not have been ignored for as long as he was.
Byrne writes of Everett's views: "the splitting of observers share an identity because they stem from a common ancestor, but they also embark on different fates in different universes. They experience different lifespans, dissimilar events (such as a nuclear war perhaps) and at some point are no longer the same person, even though they share certain memory records." Everett says that when a observer splits it is meaningless to ask "which of the final observers corresponds to the initial one since each possess the total memory of the first" he says it is as foolish as asking which amoeba is the original after it splits into two. Wheeler made him remove all such talk of amoebas from his published short thesis.
hypothesis of scientific realism at all costs. — Wayfarer
A lot of it is indeed misrepresented. The people updating the wiki perhaps have not actually read the thesis. The first half of the first sentence is a different wording of what I quoted, that closed systems evolved according to the Schrodinger's equation. The rest is implications of that one presise, not additional premises. Wave function collapse violates the premise, but is not explicitly stated. They put "universe" in quotes there, and that's OK, because they mean 'worlds', which most laymen take for 'planets' instead of the mathematical meaning. There is no implication of actual multiple universes. It is one wavefunction with multiple solutions.You misrepresent what Everett proposes
— noAxioms
Well, perhaps the Wikipedia entry on the topic needs to be updated, because it begins:
The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse. Many-worlds implies that all possible alternate histories and futures are real, each representing an actual "world" (or "universe"). In layman's terms, the hypothesis states there is a very large—perhaps infinite[2]—number of universes, and everything that could possibly have happened in our past, but did not, has occurred in the past of some other universe or universes.
The quantum-mechanical "Schrödinger's cat" theorem according to the many-worlds interpretation. In this interpretation, every event is a branch point; the cat is both alive and dead, even before the box is opened, but the "alive" and "dead" cats are in different branches of the universe, both of which are equally real, but which do not interact with each other.
So - this is all wrong? — Wayfarer
There is no implication of actual multiple universes. — noAxioms
The people updating the wiki perhaps have not actually read the thesis — noAxioms
Not sure how copenhagen interprets the cat thing — noAxioms
A "potential world" (what we see in our minds as virtual action) does not entail an actual world (the MWI) solution. — Rich
Yet despite not being actual, it has actual effects. — Andrew M
It came to be called ‘the many worlds theory’ because according to it there are an infinite number of universes which allow all possible observations to be realised in one of those universes. — Wayfarer
So, in line with the principle that ‘drastic problems call for drastic solutions’, the question I asked is, if as drastic a solution as ‘many universes’ is warranted, what is the drastic problem that it is responding to? ‘If the many-worlds formulation were found to be impossible in principle, then we would be obliged to accept that: ...’ — Wayfarer
To begin with, I find that there is ambiguity with "self" which I think I should try to expose to some extent... — Metaphysician Undercover
Special relativity explicitly denies that there is such a thing as absolute rest, and by replacing absolute rest with the constant, the speed of light, it produces a condition in which the "correct" way of representing motions is in relation to light. However light is itself a thing in motion, and this assumes that time is necessarily passing. The constant, or fundamental premise is the activity of light, and activity assumes that time is passing. So this is fundamentally different from the premise of absolute rest, which assumes the immaterial soul to be at a point where no time is passing. The difference being that absolute rest provides a viewpoint for the observation of time passing and therefore all motions, while special relativity ties "time passing" to the activity of light. So special relativity provides no viewpoint to observe the activity of light, and if there is any inaccuracy in the assumed relationship between time passing and the activity of light, then there is a tinted glass problem.
The consequence of this difference is that the premise of the non-dimensional point, absolute rest provides a position to view all motions in relation to each other, including the motion of light. The premise of special relativity does not allow this, because it sets as the viewpoint, the activity of light. So the soul's perspective, from special relativity, is as moving light, a photon or some such thing, and all other motions are viewed from this perspective. If we had a complete understanding of the activity of light, and how other activities related to it, then we could use this as an accurate viewpoint. But we do not, so we have created for ourselves, a tinted glass problem. We have assumed a perspective, the activity of light as a constant, without properly understanding that perspective, and what it adds to (how it tints) our observations. — Metaphysician Undercover
I would disagree. Opponents take a distinction that arises naturally in everyday experience and then their conclusion generally involves denying that same distinction. For example, "How do you know everything isn't an illusion?" or "We don't perceive things as they really are, because illusions". — Andrew M
Perhaps so, but his "primary qualities" and "secondary qualities" isn't a natural distinction. Trying to draw a line regarding which qualities the apple "primarily" has is to misunderstand the nature of language abstraction. — Andrew M
I find Rovelli's RQM very intriguing as well, but it is a realism of sorts. Its difference to MWI is that only interactions of other systems with the system in question define what is real for that system. So you can't compare accounts between systems until they interact, in which case their respective accounts will always be found to be consistent. — Andrew M
It seems only as many as is necessary. Note that the vast size of Hilbert space is the same under all interpretations. If it is not interpreted physically, then where do the unitary transformations happen? — Andrew M
In my view the universe just is quantum mechanical at base. If decoherence emerges from QM, then perhaps gravity does as well. For a possible explanation along these lines, see Sean Carroll's recent talk entitled "Extracting the Universe From the Wavefunction". The main idea starts at 29:49. — Andrew M
However all "universes" are in fact an "aspect" of the same "thing" in MWI! — boundless
However there are still two possible (very inelegant, but possible) solutions, maybe. — boundless
The first is this: "c" is the speed limit of relativity. Strictly speaking relativity does not imply that light moves as fast as "c". Interestingly you can read this article https://www.sciencealert.com/heavy-light-could-explain-dark-energy . This solution is very inelegant, especially due to Gauge symmetry problems. But IMO it is possible. If indeed no particle is massless, then IMO the tinted glass issue can be circumvented. — boundless
However all "universes" are in fact an "aspect" of the same "thing" in MWI! — boundless
Everett was disappointed at the poor reception his doctoral dissertation received and never published anything on quantum mechanics again for the rest of his life; instead he became a Dr. Strangelove type character making computer nuclear war games and doing grim operational research for the pentagon about armageddon. He was one of the first to point out that any defense against intercontinental ballistic missiles would be ineffectual and building an anti-balistic missile system could not be justified except for "political or psychological grounds". Byrne makes the case that Everett was the first one to convince high military leaders through mathematics and no nonsense non sentimental reasoning that a nuclear war could not be won, "after an attack by either superpower on the other, the majority of the attacked population that survived the initial blasts would be sterilized and gradually succumb to leukemia. Livestock would die quickly and survivors would be forced to rely on eating grains potatoes and vegetables. Unfortunately the produce would be seething with radioactive Strontium 90 which seeps into human bone marrow and causes cancer". Linus Pauling credited Evert by name and quoted from his pessimistic report in his Nobel acceptance speech for receiving the 1962 Nobel Peace prize.
Hugh's daughter Liz Everett killed herself a few years after her father's death, in her suicide note she said "Funeral requests: I prefer no church stuff. Please burn me and DON'T FILE ME. Please sprinkle me in some nice body of water or the garbage, maybe that way I'll end up in the correct parallel universe to meet up with Daddy". And so she was.
In the new paper, three scientists argue that including “potential” things on the list of “real” things can avoid the counterintuitive conundrums that quantum physics poses. ... At its root, the new idea holds that the common conception of “reality” is too limited. By expanding the definition of reality, the quantum’s mysteries disappear. In particular, “real” should not be restricted to “actual” objects or events in spacetime. Reality ought also be assigned to certain possibilities, or “potential” realities, that have not yet become “actual.” These potential realities do not exist in spacetime, but nevertheless are “ontological” — that is, real components of existence. [In my heuristic: real but not existent.]
“This new ontological picture requires that we expand our concept of ‘what is real’ to include an extraspatiotemporal domain of quantum possibility,” write Ruth Kastner, Stuart Kauffman and Michael Epperson.
By expanding the definition of reality, the quantum’s mysteries disappear. In particular, “real” should not be restricted to “actual” objects or events in spacetime. Reality ought also be assigned to certain possibilities, or “potential” realities, that have not yet become “actual.” These potential realities do not exist in spacetime, but nevertheless are “ontological” — that is, real components of existence. [In my heuristic: real but not existent.]
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