Tuesday, April 9, 2013

Testability of many-worlds interpretation

I got this comment below:
You mention the many worlds interpretation, which is an untestable idea about the interpretation of quantum mechanics that pretty much nobody is working on. So I'm not sure that we need to "throw out" many worlds.
Here is Scott Aaronson plugging his new quantum computing book on Lumo's blog, of all places:
Why does David Deutsch (one of the originators of QC) think that a scalable quantum computer would be a powerful demonstration of the truth of the many-worlds interpretation? What are the counterarguments to Deutsch's position?
I haven't read the book yet, but I cite this to show that Deutsch believes many-worlds is testable. Furthermore, many-worlds appears prominently in popular explanations of modern physics, such as Brian Greene's latest book.

I agree that many-worlds is untestable, but it is worse than that, and should really be thrown out like yesterday's newspaper. It has no theoretical value and it explains nothing. It only causes confusion, largely because it makes probabilities meaningless.

I will probably buy the print edition of Aaronson's book, when it comes out in a couple of months. He is an expert on the subject, and explains things well, even if he has trashed me personally. He is a quantum computing enthusiast, and I am a skeptic, but he actually agrees with me that scalable quantum computing is an unproven concept. If you cannot wait for the book, some draft lecture notes are freely available. There is also a funny video commercial with models summarizing his opinion that quantum mechanics is "about information, probabilities, and observables, and how they relate to each other."

He likes to explain quantum mechanics in terms of negative probability. I don't find this view particularly helpful, but maybe I should reserve criticism until I see the book.

Update: It is funny how Aaronson cannot mention Motl without a digression into a denunciation of his politics:
“Let’s be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world. In science, consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus.” -Michael Crichton

That Michael Crichton quote is one of the dumbest things I’ve ever read. ...

What do you make of the fact that the two theoretical physicists alive today who are arguably the most “Feynmannian” — Murray Gell-Mann and Steven Weinberg — are both on record strongly supporting the current scientific consensus on AGW, as is Stephen Hawking and pretty much every other celebrated physicist you’ve ever heard of, with Freeman Dyson the sole semi-skeptic that I know about? ...

No, I don’t demand “proof” that a new technology is safe before anyone can use it: “proof” outside of pure mathematics is a concept for crackpots. ... it seems obvious to me that the burden should lie squarely with the deniers, to convince the scientific community that the current emissions levels pose merely an “acceptable” degree of risk. So far, they’ve noticeably failed to do so.
Aaronson is a left-winger, and seems very annoyed that Motl and Dyson do not conform to the so-called consensus.

None of these folks are climate scientists, so they are out of their expertise. Motl frequently posts climate data and arguments on his blog. But Aaronson does not address the substance of any of those posts. He just doesn't like Motl's politics, and complains about a view against the consensus.

Aaronson makes a similar argument for quantum computing. He says that there is a consensus in favor of scalable quantum computing, and the burden of proof should be on the skeptics. That is a weak argument.

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