Many Worlds is like Superdeterminism

I posted this provocative comment on Scott Aaronson's blog:

MWI fails to resolve the measurement problem, as Fred #14 explains, but the problems are much worse. Scott has explained that superdeterminism is contrary to scientific thinking, and so is MWI, for somewhat different reasons.

Superdeterminism makes randomized controlled experiments impossible, because hidden dependencies control the outputs. MWI also rules out free will, and then makes it impossible to interpret outcomes. If you do an experiment with ten possible outcomes, and see one, you learn nothing because all of the other possibilities occur in parallel universes. MWI might be of some use if it were able to say that some universes were more probable than others, but it cannot do that. So MWI also makes experiments impossible.

MWI does not make any successful predictions, unless you add the Born rule and do Copenhagen in disguise. Just like the superdeterminists, the MWI advocates seems to be willful contrarians who do not actually have a quantitative theory to back up their ideas.

Aaronson says that he is mostly on board with the Many Worlds Interpretation. He says:

I already teach MWI in my undergrad quantum information class, in such a way that according to the poll we give at final exam time, roughly half the students end up as MWI proponents (with the others split among Bohm, Quantum Bayesianism, Penrose-style dynamical collapse theories, agnosticism, and rejection of the whole question as meaningless).

Deutsch is a big believer in quantum computing, and says it would prove many-worlds, as the extra worlds could explain where the magic computation takes place. My view is the contrapositive. I think many-worlds is nonsense, and that makes me skeptical about quantum computing.

I will be interested to see what pushback I get. Surely the MWI believers will say that I am wrong.

Update: Not much response so far. One guy has a link to a paper arguing for the Born rule, but that's all.

A video interview of Deutsch on many-worlds, which he prefers to call the multiverse, was just posted. He claims great importance to the concept, but when asked to quantify the universes, he cannot give a good answer.

Update: Still no serious defense of MWI. Weird. Maybe they only believe in it to the extent that they do not have to defend its inadequacies. Finally, the thread is being hijacked by "Feminist Bitch" who complains that "we get a pseudo-intellectual rationalist-tier rant about whatever’s bumping around Scott’s mind right now." Not enough about her favorite leftist feminist causes. Sigh.

Update: And now Aaronson has been shamed into donating to feminist causes:

I stayed up hours last night reading Alito’s leaked decision in a state of abject terror. I saw how the logic of the decision, consistent and impeccable on its own terms, is one by which the Supreme Court’s five theocrats could now proceed to unravel the whole of modernity.

So the whole of modernity depends on imposing illogical rulings on the people?

Update: Aaronson has closed the thread after detailing how he was bullied as a child. He is annoyed that feminists and others demand special oppression status, while no one has any sympathy for nerds like him.

Maybe a Monkey Threw the Paradigm-Shifting Ashtray

I mentioned how a famous documentary film maker wrote a book trashing the famous paradigm shift professor.

The professor is now dead, and his archivist published a defense. The filmmaker got the professor's brand of cigarettes wrong. And maybe a monkey threw the ashtray, not the professor. And reports that the professor had multiple monkeys in his office were exaggerated.

I post this to help complete the record.

The real problem with Professor Paradigm Shift is not his ashtray, or even his philosophy, but how his famous book convinced much of academia that science is just a system of following faddish beliefs, with no theory being objectively better than any other.

Topological Quantum Computer Progress Retracted

One of the more exciting approaches to quantum computing is the topological quantum computer. This is the approach that Microsoft is betting on. If possible, it would solve some error correction problems.

If possible. Advances in the field keep getting announced, and retracted.

Retraction Watch reports:

A year after retracting a Nature paper claiming to find evidence for the elusive Majorana particle that many hope would have paved the way for a quantum computer, a group of researchers have retracted a second paper on the subject from the same journal.

Scott Aaronson reports:

Last month, Microsoft announced on the web that it had achieved an experimental breakthrough in topological quantum computing: not quite the creation of a topological qubit, but some of the underlying physics required for that. This followed their needing to retract their previous claim of such a breakthrough, due to the criticisms of Sergey Frolov and others. One imagines that they would’ve taken far greater care this time around. Unfortunately, a research paper doesn’t seem to be available yet. Anyone with further details is welcome to chime in.

One imagines. Okay, I can imagine.

Carroll Attacks Libertarian Free Will

Sean M. Carroll claims that he defends free will, but on his latest podcast, he says that libertarian free will violates the laws of physics, and is therefore impossible.

He says he believes in compatibilist free will, where all our actions are determined by past events, but we have an illusion of making choices.

Here is a recent philosophy paper on free will. It also defends free will only in some contrived sense.

If free will violates the laws of physics, then what law is violated? Where is the scientific paper that made this discovery? Who got the Nobel Prize for this scientific breakthrough that resolved millennia of philosophical arguments?

None of this can be explained, of course. Carroll is just relying on his peculiar prejudices.

He has a few, if you listen to him. The biggest is that he subscribes to many-worlds theory. That really is contrary to a scientific understanding of the world. Just listen to him try to explain how he might be split into an identical copy who is then wiped out by a vacuum decay in a parallel world. And how probabilities have no meaning in many-worlds, but we try to be good Bayesians anyway, and probability is how we like to think of the world. It is all the same as if he lives in an imaginary simulation where anything can happen.

Why Goedel was Important to Mathematics

Jordan Ellenberg is a genius mathematician who wrote this 2005 Slate essay:

Goldstein calls Gödel’s incompleteness theorem “the third leg, together with Heisenberg’s uncertainty principle and Einstein’s relativity, of that tripod of theoretical cataclysms that have been felt to force disturbances deep down in the foundations of the ‘exact sciences.’ “ ...

In his recent New York Times review of Incompleteness, Edward Rothstein wrote that it’s “difficult to overstate the impact of Gödel’s theorem.” But actually, it’s easy to overstate it: Goldstein does it when she likens the impact of Gödel’s incompleteness theorem to that of relativity and quantum mechanics and calls him “the most famous mathematician that you have most likely never heard of.” But what’s most startling about Gödel’s theorem, given its conceptual importance, is not how much it’s changed mathematics, but how little. No theoretical physicist could start a career today without a thorough understanding of Einstein’s and Heisenberg’s contributions. But most pure mathematicians can easily go through life with only a vague acquaintance with Gödel’s work. So far, I’ve done it myself.

He has this backwards. He thinks Einstein invented relativity!

If numbers are real things, independent of our minds, they don’t care whether or not we can define them; we apprehend them through some intuitive faculty whose nature remains a mystery. From this point of view, it’s not at all strange that the mathematics we do today is very much like the mathematics we’d be doing if Gödel had never knocked out the possibility of axiomatic foundations. For Gödel, axiomatic foundations, however useful, were never truly necessary in the first place. His work was revolutionary, yes, but it was a revolution of the most unusual kind: one that abolished the constitution while leaving the material circumstances of the citizens more or less unchanged.

No, Goedel did not knock out the possibility of axiomatic foundations. He showed, more than any other single person, that mathematics could be founded on axioms.

He showed that first order logic was strong enough to prove statements that are true in every model. He showed how set theory axioms could help answer questions like the continuum hypothesis. Before him, we did not know that first-order logic would suffice for math foundations. After him, there was a consensus that ZFC works.

Before ZFC, we did not have rigorous constructions of the real number line, or a good concept of a function. And certainly not manifolds or vector fields or Banach spaces. Mathematicians take these things for granted today, but only because of foundational work done in the early XX century. Logicism did not fail.

It is not true that the axiomatic foundations are not necessary. It was not true for Goedel, and not true for the rest of Mathematics. Perhaps Ellenberg has managed to avoid logical subtleties in his papers, but that is only because others have done the foundational work that he built on.

Another way in which Goedel's work has transformed Math is that he invented computability for his famous theorem. It depends on the axioms being recursively enumerable. This became a core concept for theoretical computer science. It is important for math also. I would say that all pure mathematicians should have a basic understanding of first-order logic, ZFC, and computability.

Others do say similar things about Goedel, such as this 1915 book:

John von Neumann, who was in the audience immediately understood the importance of Gödel's incompleteness theorem. He was at the conference representing Hilbert's proof theory program and recognized that Hilbert's program was over.

Hilbert's program was to axiomatize mathematics. That was not over. It had just gotten started. Only a very narrow and unimportant part of it was over. That is, self-consistency could not be proved, and would not help even if it could be.

New Video on Entanglement

Brian Greene leads a video discusssion on Einstein and the Quantum: Entanglement and Emergence.

Everyone seems to accept that entanglement is the big mystery of quantum mechanics. I do not agree.

The favorite example of entanglement is when two identical particles get emitted from the same source, and then the spin of one is correlated with the spin of the other, even if they are far apart.

This by itself is not so strange, as the same thing happens classically. Because of conservation of linear and angular momentum, a similar classical particle ejection would also yield distant correlations.

Greene would day that the quantum correlations work differently. Okay they do. But then you have to be talking about that difference as being the quantum mystery, because if you just talk about the distant correlation, there is no quantum mystery.

The quantum spins work differently because of the uncertainty principle. The measured spin depends on how the measurement is made. Classical mechanics allows modeling position, momentum, and spin without saying how they are measured.

Okay, yes, that is an important difference, but what does it have to do with entanglement? The entanglement is just a smokescreen added to confuse you.

I did learn one thing. I always thought that the EPR paradox was named after the initials of that 1935 paper. It also stands for Element of Physical Reality. The central claim of that paper is a complete theory must represent every element of physical reality. If a measurement outcome is determined by another distant measurement, then that is such an element, but quantum theory uses wave functions instead for the dynamical theory.

Again, the real mystery here is the uncertainty principle, which implies that the measurement outcome depends on how the measurement is done. The fact that there is a distant correlation would be true about any theory.

Nobody thought that 1935 paper was any big deal until Bell showed in the 1960s that the quantum correlations could be quantitatively distinguished from the classical correlations. He also renamed the elements of physical reality as beables. He wanted to follow Einstein's dream of having a theory based on beables, like classical physics, instead of wave functions. The Bell test experiments proved this to be impossible.

Recent Postings against Free Will

Here are a couple of recent postings against free will. Sam Harris argues in a podcast that he does not even have the feeling of making free choices.

I think he suffers from a mental disorder.

Physicist Coel Hellier argues Human brains have to be deterministic (though indeterminism would not give us free will anyhow).

It appears to me that his main argument is that no one can give a mechanistic deterministic account of how free will works.

I say that it would not be free will, if that were possible.

I am particularly baffled that any scientist would make this argument. We cannot give a mechanistic deterministic account of how quantum mechanics works. Bell's theorem shows that is impossible. All physicists know this. So why should anyone expect such an explanation of free will?

Mathematician Gil Kalai is a well-known quantum computer skeptic, and a believer in free will. He has a new paper relating these views, Quantum Computers, Predictability, and Free Will. He denies that quantum supremacy has been achieved.

Philosophy of Quantum Mechanics

This new survey is pretty good:

Wallace, David (2022) Philosophy of Quantum Mechanics. [Preprint]

This is a general introduction to and review of the philosophy of quantum mechanics, aimed at readers with a physics background and assuming no prior exposure to philosophy. It is a draft version of an article to appear in the Oxford Research Encyclopedia of Physics.

It is a little too favorable towards many-worlds:

Among physicists, the (more operationalist versions of the) probability-based approach, and the Everett interpretation, are roughly as popular as one an- other, with different sub-communities having different preferences. (The mod- ificatory strategies are much less popular among physicists, although they are probably the most common choice among philosophers of physics.) But more popular than either is the ‘shut-up-and-calculate’ approach [154]: the view that we should not worry about these issues and should get on with applying quan- tum mechanics to concrete problems.